CZ38598U1 - Heat storage - Google Patents

Description

Heat storage

Technical area

The technical solution relates to a heat storage tank containing storage tanks filled with a heat transfer fluid.

State of the art

Heat is largely used for year-round water heating in apartments, industry and services, and for heating them in winter.

Heat is also used in cooling or air conditioning in the summer, as long as the heat transfer fluid has a low temperature.

Heating plants, which use fossil fuels that can be stored easily, are used to generate heat for large urban agglomerations. Their output can be regulated quite quickly and increased in winter according to the weather, but for ecological, economic and political reasons their operation must be limited.

Producing gas by electrolysis of water for storage and combustion during the heating season is uneconomical.

Solar and wind power is increasingly being produced more and more cheaply, but it is still erratic. In winter, the output of these power plants is insufficient and unreliable.

Thermal power plants for heating are powered by electricity, and its seasonal consumption places a significant burden on power plants and can therefore make heat production unpleasantly more expensive.

Nuclear power plants are also considered to be ecological energy sources, but for the purposes of heat supply they are distributed unevenly across the country and require constant energy consumption, otherwise the economics of their operation deteriorate. The planned small nuclear power plants or heating plants will also require constant energy consumption.

Also in summer, electricity production in thermal power plants increasingly faces major problems due to insufficient cooling of condensate, as they are increasingly burdened by the operation of air conditioning equipment.

Heat consumption and heat production from renewable sources is not uniform, it fluctuates during the day and in longer intervals. On the other hand, the production and regulation of heat from fossil fuels is not always very advantageous, which is why heat storage in heat storage tanks is increasingly used.

Heat storage tanks are also part of various technologies for long-term electricity storage with large outputs and capacities, such as compressed air energy storage systems (CAES), liquefied air systems (LAES) or Camot batteries (CB).

In heat storage tanks, heat is stored in a heat transfer fluid because heat is easily transported through it and the fluid ensures excellent contact with the heat exchange surface.

A fluid is a liquid or gas. A liquid is usually water, oil, salt solutions or liquefied salts or metals.

Water has the additional advantage of having a high specific heat, being easily available, safe and having good thermal conductivity over other liquids for heat storage.

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To store heat using a fluid, a heat storage tank usually uses storage tanks, which are placed separately next to each other and each is separately provided with thermal insulation, which is a relatively expensive, if not the most expensive, item in the total price of storage tanks.

For manufacturing and assembly reasons, these storage tanks are manufactured with a width or diameter of up to several meters.

The heat storage tank is usually placed on a solid base, i.e. on the subsoil.

A foundation can be concreted on the subsoil, on which the storage tank is placed.

However, most often, the heat storage tank is arranged so that a pedestal is placed on the foundation and the storage tank is placed on it.

With this arrangement of storage tanks, operation and maintenance have good access to the entire surface of the storage tank, but the surface of the storage tank is relatively large in relation to the volume of the storage tank, so the cost of insulation and heat losses through insulation are relatively high, which significantly increases the total cost of heat stored in the heat storage tank.

The amount of heat stored in the heat reservoir changes by changing the amount and/or temperature of the heat transfer fluid.

Short-term, i.e. daily, at most weekly heat storage can be economically ensured in existing facilities, but long-term - seasonal heat storage, i.e. heat storage for a period of at least 6 months to one year, is uneconomical, which is why heat storage tanks for large capacities do not actually exist.

Therefore, it is increasingly urgent to address long-term heat storage in a way that is cheap and available in large quantities, and that its production can be ensured as much as possible from ecological sources, preferably only from renewable sources, in order to limit atmospheric warming.

US patent application US2011146940A1 describes piping in a latent heat storage tank system, the system also including thermal insulation.

Japanese patent JP 6896532 B2 describes a heat storage device comprising two tanks, both of which are provided with foldable individual thermal insulation and the entire tank is covered by an open casing which is formed by a top wall and side walls, but not a bottom wall. The invention is directed to an arrangement of support legs for a heat storage device, where four legs are sufficient to support two tanks by screwing these tanks together.

Korean patent application KR 2022001098 A describes a heating system for heating a greenhouse with a series connection of heat storage tanks.

None of the above documents deals with the protection of the tank material and/or its thermal insulation.

The task of the technical solution is to solve a space- and structurally efficient device that will enable the long-term economical storage of heat in large quantities, especially for the purposes of seasonal heating or cooling of residential and non-residential spaces, while enabling the effective use of ecological energy sources with constant and variable production.

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The essence of the technical solution

The technical solution solves the above-mentioned problem with a heat storage tank, which includes a system of modules, wherein in the system of modules each module includes a storage tank filled with a heat transfer fluid. At least two modules have the same or different diameter, the same or different height, and their spacing is greater or smaller than their diameter or equal to their diameter. A separate circulation pipe is connected to each storage tank or a common circulation pipe is connected to at least two storage tanks. The system of modules is provided with thermal insulation. The essence of the above-mentioned heat storage tank is that the system of modules is provided with a gas-tight casing. The system of modules is placed on foundations with a gas-tight casing so that at least one module is built on a separate foundation formed in the subsoil or the entire system of modules is built on a common foundation formed in the subsoil. The gas-tight casing is made of corrugated, edged or thin-walled sheet metal, or of thin-walled laminated material, or of non-metallic materials, or is created by a gas-tight coating on the perimeter structure or on the perimeter thermal insulation of the module system.

Preferably, the module comprises a base positioned under one or more storage tanks.

The heat storage preferably includes a heat supply device and a heat extraction device, which are connected to the storage tanks preferably via a circulation pipe and a circulation unit.

All storage tanks contained in the heat storage system form a storage tank system.

A storage tank system may contain groups of storage tanks.

A group of storage tanks may consist of storage tanks that have a common base or a common circulation system, or another common element.

The heat storage tank preferably comprises a set of modules, each module comprising a storage tank.

The module preferably includes a base positioned below the storage tank.

The heat storage tank preferably contains energy modules in which circulation units and/or circulation pipes, or other energy equipment, are located.

All modules contained in the heat storage tank form a module system.

The module system may comprise a group of modules, preferably comprising a group of modules or a group of energy modules.

A group of modules may be formed by modules that also have a common base and/or a common circulation unit, or another common element.

The surface of the part of the heat storage containing the storage tanks is preferably provided with a gas-tight jacket.

The surface of the part of the heat storage containing the storage tanks and bases is preferably provided with a gas-tight jacket.

The circulation pipe can also be protected with a gas-tight jacket, either separately or together with the storage tanks.

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The gas-tight jacket allows the inner space of the gas-tight jacket to be filled with a suitable gas, preferably a dry gas, preferably an inert gas, to limit corrosion of the metal parts of the heat storage device and to protect the thermal insulation against weathering by atmospheric oxygen.

The heat storage tank preferably comprises a perimeter structure to which a gas-tight jacket is attached. This protects, in particular, the high modules in the heat storage tank against wind gusts; these modules and their anchoring or their possible interconnection then do not have to be dimensioned for strong crosswinds, which further reduces the costs of manufacturing the heat storage tank.

The surface of at least part of the heat storage tank is preferably provided with thermal insulation.

The surface of the part of the heat storage containing the storage tanks is preferably provided with thermal insulation.

Preferably, the thermal insulation is fixed to a perimeter structure that carries the gas-tight jacket.

The thermal insulation could be placed inside or outside the gas-tight casing.

Placing thermal insulation inside the gas-tight jacket ensures better protection against heat loss from the heat storage by preventing the escape of heated gas, especially inert gas, from the interior of the gas-tight jacket, and also protects the thermal insulation against weather conditions and solar radiation.

The gas-tight jacket itself is then protected by thermal insulation against the hot environment inside the heat storage tank and is not exposed to temperature fluctuations of the stored water.

Advantageously, this gas-tight jacket allows a slight gas overpressure to be maintained inside the jacket to increase security against the ingress of air from the outside environment and also to create a prestress in the gas-tight jacket that prevents its deformation due to atmospheric pressure changes, e.g. during gusts of wind.

The gas-tight casing is preferably made of corrugated or edged sheet metal so that it expands better due to temperature changes.

Parts of the heat storage tank, especially the storage tank, but also other structures, can thus be made of cheaper steel without reducing the service life of the heat storage tank.

Preferably, this gas-tight casing is made of thin-walled sheet metal, preferably stainless steel, preferably steel with increased corrosion resistance.

Advantageously, this gas-tight jacket can be made of a thin-walled laminated material, which is cheaper but has lower strength, therefore it will be advantageously fixed to the supporting structure at shorter distances.

Preferably, this gas-tight jacket is formed from non-metallic materials or even a gas-tight coating on the perimeter structure or on the perimeter thermal insulation of the module assembly. Such materials may be less expensive than metallic materials, but may have less resistance to ultraviolet radiation, thereby reducing their service life.

Individual storage tanks or individual modules can also be provided with thermal insulation and/or a gas-tight jacket. However, this embodiment of the heat storage is very expensive compared to insulating and jacketing the entire module system as described above.

The gas-tight casing is preferably provided with safety valves and/or fuses that prevent the safe overpressure or underpressure of the inert gas from being exceeded, so that the heat storage tank cannot be damaged.

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For access of inspection and maintenance personnel to the interior of the heat storage tank enclosed by a gas-tight casing, entrance openings with gas-tight doors are preferably made in the peripheral structure. Parts of the peripheral structure are preferably made removable or hinged to allow for the replacement of larger parts of the heat storage tank.

The heat transfer fluid for heat storage is preferably a liquid, preferably water, because it has the highest specific heat of common liquids, is easily available, safe and has good thermal conductivity.

Preferably, in the following text, the heat transfer fluid is water.

The water may advantageously be chemically treated to reduce corrosive aggressiveness and may also be treated to ensure biological safety.

Fresh water from a river or lake is preferably used, which provides better protection against corrosion, especially for the internal spaces of the storage tanks. This is also advantageous when the heat storage is located in the sea (which contains salt water).

Storage tanks can be open to the environment or closed.

In open storage tanks, ordinary or partially treated water, preferably treated by filtration, can be used as the liquid, so that the surrounding environment cannot be endangered in the event of accidental leakage of water from the storage tanks.

In a closed design of storage tanks, the water can be advantageously thickened with soluble or insoluble substances, thereby achieving higher transmitted power, and can be treated to reduce erosive or corrosive effects on heat storage components or to reduce the formation of mineral deposits.

In the closed design of storage tanks, water does not evaporate into the surrounding air and there is no need to refill it.

If the storage tank system is cubic in shape, where a is the width of the cube, then the volume of the storage tank system can be expressed by the relationship V=a ³ and the surface area of the storage tank system can be expressed by the relationship S=6.a ² .

The ratio of the surface area to the volume of a storage tank system is expressed by the relationship k=S/V=6/a, from which it is clear that this ratio decreases with increasing width of the cube.

As the dimensions increase, the surface area of the storage tank system and the cost of the necessary thermal insulation decrease relatively, resulting in a decrease in the specific costs of heat storage.

The larger the storage tank system, the longer and at a higher temperature it can retain heat.

The efficiency of the heat storage is therefore higher than in existing long-term heat storage facilities, in which the storage tanks are insulated separately, individually.

The storage cycle is the heating and cooling of water in the heat storage tank by a specified temperature difference, e.g. by 20 °C, in the range of e.g. 55 to 75 °C.

As the difference between the water temperature and the surroundings increases, heat losses increase and the cost of thermal insulation increases.

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The course of the storage cycle depends on the type and method of operation of the heat source and the type and method of operation of the heat consumer.

Water heating and water cooling can be operated in different ways:

- successively;

- simultaneously;

- independently of each other;

- with variable frequency, with variable intensity.

After the start of operation, heat is supplied to the heat storage tank, while the temperature of the stored water gradually increases until it reaches a set limit, at which time heat can be removed from the tank.

After the start of operation of the heat storage for the needs of the housing estate, heat will preferably be added to the heat storage gradually over 4 to 6 months and as soon as the water temperature reaches the required value, e.g. 55 °C, it is possible to start supplying heat to the housing estate, year-round for heating domestic water and in winter for heating apartments.

If heat is supplied to the heat storage tank throughout the year, albeit irregularly, it can also be withdrawn outside the heating season, e.g. to heat water in swimming pools.

Several storage cycles can take place in the heat storage tank throughout the year.

If the housing estate is not too far away, it is advantageous to maintain the water temperature in the heat storage tank within the range of 55 to 75 °C. If the water temperature rises above the specified maximum value before the start of the heating season, it is advantageous to also use the heat in recreational facilities, e.g. in public swimming pools.

The efficiency of heat utilization in a heat storage tank increases with increasing size of the heat storage tank, with better and stronger thermal insulation, and also with a greater number of storage cycles per year, i.e. with combined use not only in the winter period, but throughout the year.

The heat losses of the heat storage tank remain essentially the same with different numbers of storage cycles, but the total amount of heat supplied and withdrawn can be significantly higher with combined use, so that the total heat utilization can be, for example, up to 80%, within the range of temperatures suitable for heating.

The upper bottoms of storage tanks in an open design are preferably equipped with a short ventilation pipe, through which the internal air space above the water surface is preferably freely connected to the ambient air, thereby preventing an increase in internal air pressure when filling the storage tanks or the creation of air underpressure when draining the storage tanks, and the internal pressure in the storage tanks is caused only by the hydrostatic pressure of the water filling.

In the closed design of storage tanks, the gas space above the liquid level in the storage tanks is separated from the ambient atmosphere and the gas pressure in the base tank does not have to be equal to the ambient atmospheric pressure. Evaporation of the water filling in the heat storage tank is prevented and thus the formation of mineral deposits on the inner walls, especially of the storage tanks, is also limited. The water filling in the storage tanks then does not change its weight, it does not need to be topped up and it can be easily stabilized and its purity and chemical composition can be controlled.

An inert gas, preferably nitrogen, can be advantageously used here, which is more expensive but reduces corrosion of the components of the heat storage system, in particular the storage tanks and pipes.

A vent pipe branch is preferably located at the top bottom of each storage tank.

The vent pipe from each storage tank is preferably connected to a vent pipe network which is connected to the gas storage tank.

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Connecting the vent pipes of all storage tanks facilitates equalization of water levels in the event of uneven filling and emptying of storage tanks with water.

During repairs or in the event of a malfunction, when the filling of the storage tanks with water may change, and as a result of changes in the temperature of the water in the storage tanks, the saturated vapor pressure in the gas above the water level changes.

In order to avoid pressure overload of the storage tanks, especially for the reasons mentioned above, the gas pressure above the water level is preferably maintained at the ambient air pressure using control valves and/or safety valves.

To enable the storage of thermal energy in gas, the gas space of the heat storage tank is made up of connected gas spaces, gas tanks.

The heat storage tank can also be used to store gas pressure energy.

A tank filled with compressed gas is then called a pressurized gas tank or also a pressurized air tank if the compressed gas is air.

To be able to store the thermal energy of the liquid and the thermal and pressure energy of the gas at the same time, the storage tank can be filled with both liquid and gas, preferably compressed gas. Then the water tank is also a pressure tank.

The storage tanks are preferably placed on pedestals that create space for placing the circulation piping under the storage tanks and for work platforms for operating and maintenance personnel to walk on.

The heat storage tank requires a substrate of the required area for its placement. The substrate can have varying degrees of flexibility and strength - from solid earth to liquid.

The heat storage tank can be advantageously placed on bedrock, then it is a stable design, a stable heat storage tank.

The heat storage tank can be advantageously placed in a liquid environment, preferably in water, in a base tank, e.g. in a weir or in the sea, then it is a floating design, a floating heat storage tank.

The more load-bearing the subsoil or the greater the depth of water in the base tank, the greater the capacity of the heat storage tank.

The storage tanks and bases are placed on a supporting element in the heat storage system.

For a stable heat storage tank, the supporting element is the foundation.

For a floating heat storage tank, the supporting element is a float.

The base or float is therefore designed to support all other parts of the heat storage tank.

By immersing the float in the water in the base tank and under the influence of the external hydrostatic pressure of the water, it creates the buoyancy necessary for the floating heat storage tank to float in the water in the base tank.

The float is preferably located in the lower part of the floating heat storage tank.

The float must have a height that exceeds the water level in the base tank so as to ensure safe floating of the floating heat storage tank even at its maximum permissible inclination.

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The float and the storage tank are pressure vessels that are loaded by internal and/or external fluid pressure, therefore they are preferably provided with a lower and upper domed bottom that best withstands this load. They are preferably made of a corrosion-resistant material, preferably stainless steel.

The heat storage tank is preferably formed by a system of modules, then the heat storage tank can be called a modular heat storage tank.

The module includes a storage tank placed on a base, preferably designed so that the storage tank and the base occupy the same floor plan in the module space.

Preferably, at least two storage tanks in the storage tank system are connected by interconnecting the walls of the storage tanks using connecting components or using welds, or by connecting the storage tanks using vertical and/or horizontal stiffeners.

The interconnection of storage tanks by connecting their walls or by connecting the walls with vertical and/or horizontal reinforcements ensures, above all, sufficient cohesion, rigidity and elasticity of the storage tank system, as well as the even distribution of stress in the material.

The design of the storage tank system also allows for maximum use of the area and load-bearing capacity of the land on which it is located.

Preferably, at least two modules in the module system are connected to each other by interconnecting the module walls using connecting components or using welds or by connecting the modules using vertical and/or horizontal stiffeners attached using connecting components or using welds to the module walls.

The essence of this arrangement is that the modules, i.e. the storage tanks and the pedestals under these tanks, are placed next to each other in the module system and are always connected to each other in the same way, i.e. by connecting their walls or by connecting their walls using vertical and/or horizontal stiffeners.

The storage tank system is therefore part of the modular heat storage system.

Since the parts of the module, in particular the base, the float or even the storage tank, are loaded by the strut, the storage tank also by internal overpressure, the module for this type of load is preferably made of a cylindrical shape with a vertical longitudinal axis and a circular horizontal cross-section, preferably made of sheet metal. This shape of the module allows the highest load resistance and the best use of the structural material.

The modular design also simplifies and therefore reduces the cost of manufacturing and installing the heat storage tank.

Preferably, the module system comprises groups of modules.

In a stable modular heat storage tank, there are advantages:

- module built on a separate foundation;

- a group of modules built on a separate foundation;

- the entire system of modules is built on a common foundation.

In a floating modular heat storage tank with the advantage of:

- the module contains a float;

- the module group contains a float;

- the entire module system contains a float.

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Modules can be arranged into separate module groups.

In these module groups, the modules can be arranged advantageously:

- side by side and/or above each other;

- according to a specific shape, according to size, e.g. according to the height of individual parts, e.g. according to the dimensions or shape of storage tanks, or according to the height of pedestals;

- according to the method of interconnection by their walls and/or by means of reinforcements.

The groups of modules are preferably rigidly connected to each other, preferably in the axis of the center of gravity of each group of modules, preferably by means of vertical and/or horizontal stiffeners.

A group of modules, in which the modules are connected to each other, preferably by means of vertical and/or horizontal stiffeners, is preferably rigidly connected to some of the other modules, preferably by means of vertical and/or horizontal stiffeners.

The base reservoir may advantageously be formed by the sea or a river, an artificial water feature, a lake, e.g. at the site of an excavated surface mine, or it may be formed as a pit below the surface or as a pit open to the surface, advantageously it may be formed on the surface as a sunken base reservoir, whereby the rock excavated during the excavation of the base reservoir may advantageously be used to form an embankment or dam around the depression in order to increase the water level and thus the depth of the base reservoir.

The base tank should preferably be drainless to reduce the risk that the floating heat storage tank will be damaged when it lands on the bottom of the base tank if water is accidentally or intentionally drained from the base tank or if its dam or bottom is damaged, leaked or permeable.

Preferably, the heat storage tank is partially or fully immersed in water in the base tank, if the thermal insulation of the floating heat storage tank is sufficiently resistant to the hydrostatic pressure of the water.

Although it is technically feasible to also enclose the floats in a floating heat storage tank with a gas-tight jacket, it is more complicated and therefore more expensive.

The part of the storage tank system submerged below the water level in the base tank can function as a float.

In the submerged part, the hydrostatic pressure of the water inside the storage tanks is balanced with the hydrostatic pressure of the water outside the storage tanks, so that the storage tanks can have a reduced wall thickness.

The amount of heat stored in the heat reservoir changes by changing the amount and/or temperature of the heat transfer fluid.

If the amount of heat transfer fluid in the heat storage tank does not change, the heat transfer fluid only circulates between the heat source, the heat storage tank and the heat consumer, in which heat transfer takes place directly (i.e. by exchanging the heat transfer fluid) or via heat exchange surfaces.

The heat reservoir preferably includes a device for supplying heat from a heat source.

The heat supply device preferably comprises a heating circulation pipe with closures that connects the heat source to the heat storage tank.

Then, the heating of the heat transfer fluid in the heat storage tank is carried out by circulating the heat transfer fluid in the heating circulation pipe between the heat source and the storage tanks.

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The heat supply device preferably comprises a heat exchange surface which can be located inside or outside the storage tanks.

Then, the heating of the heat transfer fluid in the heat storage tank is preferably carried out by means of a heat exchange surface.

The heat exchange surface is preferably formed by the walls of a heating exchanger or heating element, e.g. an electric one.

An electrical line and a switchboard with an on/off switch are connected to the electric heating element.

If the heat exchange surface is located outside the storage tanks, then the heat supply device preferably comprises a heating circulation unit.

The heating circulation unit circulates the heat transfer fluid between the heat exchange surface and the storage tanks.

The heating circulation system consists of a drive motor and a pump for liquid circulation or a compressor or fan for gas circulation.

If the amount of heat stored in the heat storage tank changes by changing the amount of heat transfer fluid, the heating circulation unit can be part of the heat source, in which case an additional heating circulation unit in the heat supply device is not required.

The heat storage preferably includes a device for extracting heat to a heat consumer, which may be a heated object.

The heat extraction device preferably includes a collection circulation pipe with closures that connects the heat consumer to the heat storage tank.

Then, heat is extracted from the heat transfer fluid in the heat storage tank by circulating the heat exchange fluid in the extraction circulation pipe between the heat consumer and the heat storage tank.

The heat extraction device preferably comprises a heat exchange surface which can be located inside or outside the storage tanks.

Then, heat extraction from the heat transfer fluid in the heat storage tank is preferably carried out via a heat exchange surface.

The heat exchange surface is preferably formed by the walls of the intake exchanger.

If the heat exchange surface is located outside the storage tanks, then the heat extraction device preferably includes an extraction circulation unit.

Then, the circulation of the heat transfer fluid between the heat exchange surface and the storage tanks is carried out using a withdrawal circulation unit.

The intake circulation unit consists of a drive motor and a pump for liquid circulation or a compressor or fan for gas circulation.

The heating circulation pipe in the heat supply device is preferably fully separated from the withdrawal circulation pipe in the heat withdrawal device. Both devices can thus contain a different heat transfer fluid.

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The storage tanks can also advantageously contain a different heat exchange fluid. In such a case, the heat transfer between the heat exchange fluid in the heat storage tank and the fluids in the heat supply device or even in the heat extraction device is advantageously ensured by heat exchange surfaces.

If a modified liquid circulates in the heat storage tank, which, for example, increases the corrosion resistance of storage tanks, circulation pipes, circulation units and exchangers, it may be advantageous to protect it against losses in the event of heating system failures, which most often occur in the heated building or in the long-distance pipeline.

The collection circulation pipe in the heat collection device is therefore preferably fully separated by a collection exchanger from the object circulation pipe of the heated object. The heated object device preferably comprises an object circulation pipe, an object circulation unit and an object exchanger.

The location of the heat supply or removal equipment relative to the storage tanks also has an impact on operating costs and the price of the stored heat.

Inside the module system, there is an environment with a temperature that is not favorable for the operation of circulation units and pipeline closures or for operating and maintenance personnel, therefore it is advantageous to place circulation units and closures outside the module system.

Pipes, circulation units and closures located outside the module system are preferably thermally insulated to reduce losses of stored heat.

The stable heat storage tank is preferably equipped with a collection tank of the necessary volume for any possible leakage of liquid from some storage tanks.

The height of the water in the storage tanks determines the hydrostatic pressure of the water, which acts on the walls of the storage tanks, the circulation pipeline and the circulation unit.

The circulation unit can be placed at different heights relative to the water level in the storage tanks. This also changes the pressure load on the walls of the circulation unit.

In a floating heat storage tank, the circulation units and valves can be located at or above the water level in the base tank, making them easily accessible for installation, operation and maintenance.

During operation of the heat storage tank, the water filling level of the storage tanks is constant, therefore the main load on all parts of the heat storage tank is also constant.

In addition to the main load, it is necessary to add other, irregular loads, in particular the asymmetric load on parts of the heat storage tank caused by:

- by the action of wind;

- dynamic water surges in the circulation pipe;

- air overpressure in the ventilation pipes and storage tanks;

- temperature changes;

- in the case of a floating heat storage tank, also by tilting and swinging it on the water surface in the base tank;

- in the case of a stable heat storage tank, uneven subsidence of the subsoil.

The ground plan shape of the heat storage tank can be regular or irregular; for a stable heat storage tank, the area of suitable bearing capacity of the subsoil will need to be respected; for a floating heat storage tank, the shape of the base tank will need to be respected.

In the case of a stable modular heat storage tank, the height level of the partial surface parts of the foundation can advantageously copy the sloping relief of the subsoil on the land on which the stable modular heat storage tank will be built, while it is necessary to prevent landslides of the slope.

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In this stable modular heat storage system, it is advantageous that only storage tanks with the same construction height and the same elevation, i.e. along contour lines, are connected via circulation pipes and circulation units.

The floating heat storage tank has a simple design, its floats can advantageously copy the shape of the base tank with their walls and bottoms, in order to make the most of the base tank volume for heat storage purposes and, for example, to allow the floating heat storage tank to be placed on the bottom of the base tank during repairs. Furthermore, it can be made very voluminous, yet well balanced and with a large draft depending on the size of the base tank, especially if the base tank is formed by the sea.

It is advantageous to leave sufficient free water space around the floating heat storage tank, especially between the bottom of the floating heat storage tank and the bottom of the base tank, it is necessary to maintain a depth reserve to prevent damage to the floating heat storage tank or the base tank during lateral deflection or rocking of the floating heat storage tank in strong winds and waves or during an earthquake, when pressure surges from the base tank are better dispersed around the floating heat storage tank.

After subtracting the depth reserve from the total depth of the base tank, the usable depth remains available for submerging the floating heat storage tank.

One part of the usable depth is used for the float immersion when the floating heat storage tank is empty. The other part of the usable depth is used to increase the float immersion by initially pumping water from the base tank or another water source into the storage tanks in the floating heat storage tank. The corresponding volume of unused water must be displaced from the base tank if the total water depth in the base tank is to remain at the original value.

The capacity, weight and, consequently, the investment cost of a floating heat storage tank depend on the ratio of the water height in the storage tanks and the float's draft at a given usable depth, generally on the ratio of the weight of water in the storage tanks and the weight of the floating heat storage tank.

Due to evaporation, it is necessary to top up the water in the base tank to maintain the usable depth for safe operation of the floating heat storage tank.

Increased evaporation of water, clogging of the bottom of the base tank or increased loading of the floating heat storage tank with mineral deposits on the walls of the pipes, storage tanks or floats will reduce the usable depth of the base tank. If necessary, the floating heat storage tank can be lowered by draining water to prevent damage to the bottom of the base tank. This will reduce the capacity of the floating heat storage tank, but it will remain in operation until the usable depth in the base tank can be restored.

The bearing capacity of the subsoil in a fixed heat storage tank, as well as the buoyancy (subsidence) of the floats at the usable depth in a floating heat storage tank, are used to support the foundation, the self-weight of the heat storage tank and the weight of the water in its storage tanks.

The achievable weight of the heat storage tank is proportional to its depth or the bearing capacity of the subsoil.

The amount of heat in the heat storage tank also depends on the amount of stored water and therefore on its height in the storage tanks.

It is advantageous that the weight of the heat storage tank is used as best as possible to benefit the height of the storage tanks.

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A floating heat storage tank may have its center of gravity high above the liquid level in the base tank or above the foundation level and, especially if filled unevenly or if subjected to accidental lateral loading by strong winds, may become unstable if the design is not correct.

A tall floating heat storage tank with a slim shape therefore requires solid supports to ensure stability.

The stability of the heat storage tank can be advantageously ensured by having a sufficient width according to the bearing capacity of the subsoil. In the case of a floating heat storage tank, it is advantageous to ensure that it has, on the principle of a catamaran, a width as large as possible than its height above the water level in the base tank.

At a given height of the center of gravity of the heat storage tank, its width will be derived from the forces that can cause it to tilt, and in the case of a floating heat storage tank, also from the choice of the permissible tilt.

The height of the center of gravity of the heat storage tank depends mainly on the ratio of the weight of the water filling in the storage tanks to the weight of the heat storage tank.

By creating a connected system of smaller storage tanks in the heat storage tank, the overflow of a large volume of water in the storage tanks is slowed down or prevented, and the strength and stability of the heat storage tank is also improved.

Internal partitions and/or cavities in storage tanks have the same purpose, in addition, they are also advantageously used as reinforcements of the heat storage tank to increase its strength and dimensional stability and to reduce the wall thickness of other structural elements.

When calculating the stability of the module on the subsoil, it is necessary to consider the relevant part of the foundation.

The water circulation between the heat supply, storage tanks and heat removal must be as uniform as possible in order to minimize fluctuations in the water level in the storage tanks and thermal stress in the heat storage structure.

For a stable heat storage tank, it is important to ensure that the foundations are loaded evenly to prevent overloading and damage. For a floating heat storage tank, it is necessary to ensure that it does not tilt excessively and thus sink.

Uniform filling of storage tanks with water can be ensured by regulating the water flow rate using valves in the circulation pipe, regulating the output of the circulation units, operating the circulation units balanced to the center of gravity of the heat storage tank, operating the circulation units in groups of storage tanks and/or regulating the gas pressure above the water level in the storage tanks.

A larger number of smaller circulation units allows for better regulation of the performance of individual heat sources or consumers, while a smaller number of larger circulation units allows for better efficiency.

Regulation of water flow or air flow above the water surface is carried out by throttling their flow, and for storage tanks that are closer to the circulation system, the throttling intensity must be higher.

Increased water pressures and increased overpressure or underpressure of air in storage tanks place increased demands on the dimensioning of all parts of the heat storage tank.

Control valves can also be installed in the vent pipe branches to the storage tanks and/or in the vent pipe between the storage tanks.

The internal temperature of the heat storage tank will be elevated, which will not be a favorable environment for the reliable functioning of water and air seals.

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Water and air flow control valves will preferably be located above the storage tanks or on the side around the perimeter of the module system, i.e. in an outdoor environment, where temperatures will probably be much lower and therefore more favorable for the reliable operation of the valves.

Circulation pipe branches are preferably located in the lower bottom and/or upper bottom of each storage tank.

Preferably, each storage tank or each group of storage tanks is connected to the circulation unit by a separate circulation pipe with a closure, so that in the event of a failure of any storage tank or group of storage tanks, the operation of the other storage tanks or other groups of storage tanks does not have to be interrupted.

Although the storage tank system contains a large amount of hot water overall, if a storage tank or circulation pipe fails, only a limited amount of water will flow out through a separate circuit, so a smaller emergency sump is sufficient to capture it.

The status sensors of individual storage tanks must be located inside the storage tank system, but the evaluation meters will preferably be located outside the storage tank system, which will create more favorable conditions for their operation, service and maintenance.

The spacing of the storage tanks or modules is preferably greater than their diameter. The storage tanks or modules are then preferably connected to each other, preferably by means of vertical and horizontal stiffeners, which are attached by means of connecting parts or by means of welds to the walls of the modular tanks or modules.

Preferably, parts of the module are also reinforced with internal horizontal and/or vertical stiffeners.

Preferably, the stable or floating heat storage tank is reinforced at least at the level of the upper and lower edges of the storage tanks, the floating heat storage tank also at the level of the upper and lower edges of the floats, with horizontal flanges, which can significantly strengthen the rigidity of the module system in bending and limit the horizontal load on the pipeline.

The floats, storage tanks and pedestals in the modules are pressure vessels. As regards the main load, the floats and storage tanks are mainly loaded by internal and/or external overpressure and vertical axial force, the pedestals are mainly loaded by vertical axial force.

Modules can be manufactured advantageously with a diameter of up to 3.6 to 4.0 m, if it is necessary to transport their circular parts from the manufacturer to the assembly site by rail.

The horizontal distance between the modules, in relation to the stated diameters, should preferably be 0.4 m, generally so that the floor area of the module system is best utilized for the purposes of the heat storage, but at the same time so that bilateral inspection and maintenance of the module walls and reinforcements is enabled.

When repairing a storage tank of one of the modules, it is sufficient to empty only the given storage tank, e.g. by pumping water into another storage tank in the same module or into storage tanks in other modules. During the repair, only the storage tank being repaired will be out of operation, while all other modules can continue to operate. It is necessary to take into account an increase in shear stress between the modules.

The preferred layout of the modules in triangular formations is one that provides an optimal solution for the strength and rigidity of the module system, as well as for accessibility for inspection and maintenance of the modules.

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The system of interconnected modules is quite rigid and the individual modules are not vertically movable.

With a large width of the module system, its flexibility is still evident, and in order to make the best use of the bearing capacity of the subsoil and foundations and to prevent additional shear and bending stresses from arising in the construction of the module system, it is necessary that the pressure of the modules on their supporting elements, i.e. foundations or floats, is evenly and continuously distributed, i.e. that it corresponds to the bearing capacity of the relevant supporting element in each module.

The load-bearing capacity of the float in a floating heat storage tank is determined by hydrostatic buoyancy and will be constant throughout its service life.

However, the bearing capacity of the foundations of a stable heat storage tank may change over time. For example, due to long-term loading of the subsoil by the module system, the subsoil may become compressed and compacted.

If the subsoil under the module system is not homogeneous, especially in an undermined area, then the subsidence of the subsoil and foundations will not be uniform. The module system structure will not be evenly supported and additional shear and bending stresses will arise in it.

For this reason, it is advantageous to regularly measure and evaluate the settlements of the foundations and the entire module system.

The support of the module system must be repaired or rectified, if necessary, by changing the height of the gap between the module structure and the foundation, preferably by inserting or removing pads.

Rectification spaces are preferably formed in the modules for rectifying their position on the foundation, preferably so that the lower part of the module under the tank is provided with horizontal reinforcement and mounting holes in the walls of the module.

Lifting bags, preferably pneumatic, can be inserted into the rectification space between the horizontal reinforcement and the base through the mounting holes, and by filling the bags with air, the module can be lifted. A pad with a thickness determined according to the measurement results can be inserted into the resulting gap between the module and the base, and by releasing the air from the bags, the module can be lowered onto the pad again.

To reduce the required lifting force, it is advantageous to relieve the rectified module or adjacent modules for the duration of the rectification, preferably by pumping water into storage tanks in other modules. After the rectification is complete, the module can be loaded again by pumping water into its storage tanks.

If a stable heat storage tank is assembled from many modules, the probability of an accidental leakage of all the liquid is small.

A stable heat storage tank can therefore be built near a populated area without endangering the safety of people and property in the area.

The heat storage tank is preferably built in the area of an excavated open-pit mine that has no drainage. However, the water that flows into this area must be pumped out to prevent the heat storage tank from flooding. There may also be a risk of landslides.

The modular heat storage tank is preferably reinforced only with vertical stiffeners. The module system is then flexible in the horizontal plane.

In the case of a modular heat storage system, when rocking on the surface or when the subsoil subsides unevenly, the entire system of modules deforms like an accordion - the walls of the modules deform alternately so that the horizontal circular cross-section of the modules changes to elliptical, flattens or stretches.

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The pipeline below and above the storage tanks must be equipped with compensators to prevent stress from horizontal deformation of the storage tanks from being transferred to it.

The rigidity of the module system in the horizontal plane will be determined practically only by the rigidity of the den in the storage tanks or in the floats.

The system of modules of the stable heat storage will be particularly rigid in the area of anchoring the pedestals to the foundations.

Due to the large diameter of the modules, deformations of the module walls can be kept within the limits of the material's elasticity to prevent accidental damage.

Preferably, the perimeter modules in the floating heat storage tank are reinforced with horizontal stiffeners at a level above the water level in the base tank. These stiffeners will serve to transfer horizontal forces between the perimeter modules and the tensile anchorage of the floating heat storage tank on the shore of the base tank when the floating heat storage tank is loaded by crosswinds.

When the floating heat storage tank swings on the water surface in the base tank, the floating heat storage tank will oscillate cyclically, deforming in the horizontal plane both at the level of the floats and at the level of the storage tanks; in the first half of the cycle, it will compress in the upper plane and expand in the lower plane, in the second half of the cycle it will deform in the opposite direction.

Preferably, all modules in the module system are reinforced with connected horizontal stiffeners at a level above the water level in the base tank. The stiffeners will serve to transfer horizontal forces between the peripheral modules and the tensile anchorage of the floating heat storage tank on the shore of the base tank when the floating heat storage tank is loaded by crosswinds and will also prevent horizontal deformation of the modules at the level of the horizontal stiffener.

When the floating heat storage tank swings on the water surface in the base tank, the module system will sag, deforming horizontally slightly at the level of the floats and the vast majority of the deformation taking place at the level of the storage tanks. It will not deform horizontally at the level of the horizontal reinforcement. The advantage is that the pipes and the working platform will not deform horizontally at this level.

A stable modular heat storage tank will behave similarly.

When the subsoil subsides in a certain area within the area built up by the module system, the module system will sag, but will not deform horizontally at the level of the foundations, and the vast majority of the deformation will take place at the level of the storage tanks - in the area of subsidence of the subsoil and, consequently, the foundations, the modules will be compressed in the horizontal plane at the level of the upper edge of the storage tanks.

If the subsoil subsidence occurs at the edge of the module system, the modules will expand at the level of the upper edge of the storage tanks.

Similarly, when subjected to crosswind, the deformation of the module system is most evident at the level of the upper edge of the storage tanks.

The float is the lower part of the module, which is almost completely submerged in the base tank and its buoyancy determines the weight, and therefore the weight of all parts of the module. The float is a pressure vessel, preferably a closed pressure vessel, which is loaded primarily by the external water pressure and the weight of the supported parts of the module. The lateral external water pressure acting on the walls of the float increases linearly with the depth of immersion

- 16 CZ 38598 UI float. Floats may have internal rings to reinforce against external overpressure and to ensure dimensional stability.

The floats are preferably filled with a gas, preferably an inert gas, preferably nitrogen, preferably a dried gas, which limits corrosion of the float material.

In order to lighten the structure, the float is preferably filled with gas so that its internal overpressure is as much as possible equalized with the external overpressure of water when immersed in the base tank. The float therefore does not have to be as thoroughly reinforced against collapse as when loaded on one side by external overpressure and can be significantly lighter. The internal overpressure of the float is preferably equal to the greatest external overpressure of water, which corresponds to the full immersion of the float. The internal overpressure of the float is preferably higher than the external overpressure of water corresponding to their greatest specific immersion depth in the base tank, which increases the float's resistance to accidental external overload by hitting the bottom or to sabotage.

The horizontal stiffeners between the floats are preferably provided with openings to allow vertical flow of water around the floats, and the vertical stiffeners between the floats in the upper part of the floats are also preferably provided with openings to allow horizontal flow of air between the floats above the water surface during the vertical movement of the floats in the water when filling and emptying the storage tanks or when the floating heat storage tank is rocked on the surface of the base tank. The air space between the floats above the water surface in the base tank is loosely connected to the air space of the base tank through the ventilation openings. When the floating heat storage tank is rocked, the water in the base tank flows vertically around the floats. This limits the height fluctuations of the water level in the base tank.

During further operation, it is advantageous to close the ventilation openings to prevent water evaporation in this space and to limit the formation of mineral deposits on the outer walls of the floats. The closed space between the floats helps to compensate for the swaying of the floating heat storage tank; when the floating heat storage tank sways, the water in the base tank flows horizontally around the floats. As a result of the swaying of the floating heat storage tank, the water level in the base tank may fluctuate more in height. It is advantageous to check and possibly regulate the gas pressure in this closed space so that it does not cause the floating heat storage tank to tilt permanently. In this embodiment, it is advantageous to fill the space between the floats above the water level with an inert gas to limit corrosion of the affected part of the floats.

The foundation is preferably made of concrete, preferably reinforced concrete, preferably prestressed concrete.

When heating a system of modules, it can be expected that the foundations and steel structure of the modules will have different temperatures and therefore will exhibit different expansion.

The foundations under individual modules or groups of modules are therefore preferably separated from each other by expansion joints.

Storage tanks and floats, as well as circulation pipes and circulation units, are exposed to water, so it is advisable to make them from corrosion-resistant material, even if it is more expensive. It is advisable to protect their surface against the formation of mineral deposits.

The pedestals around the perimeter of the heat storage tank, or at least the peripheral parts of the pedestals, are preferably made of a material resistant to the corrosion of the outside air. The pedestals in the interior of the heat storage tank can then be made of a cheaper material, provided that the long-term reliability of the circulation pipe is ensured in order to prevent an increase in humidity in the pedestal area.

The modules are subjected to varying loads during operation due to changes in the water temperature in the storage tanks. Therefore, an expansion device must be installed in the pipe to continuously adjust its length.

- 17 CZ 38598 UI to temperature changes of the modules. The expansion devices are preferably bellows compensators, preferably arch compensators placed in the pipeline.

By using inert gas to fill the space above the water level in storage tanks, it is advantageous to prevent unwanted proliferation of flora and fauna in the heat storage tank, thereby increasing the density of water and wear and tear on hydraulic equipment and distribution systems.

For the above reasons, the need to clean the walls of storage tanks and pipes from organic and inorganic deposits is reduced.

The space between the storage tanks, as well as the entire space inside and outside the pedestals, may also be filled with nitrogen or another suitable inert gas, preferably dried gas, to increase corrosion protection.

The composition and pressure of the protective gas filling in the modules, in their parts and in the space between them is advantageously checked continuously using measuring instruments, which makes it possible to detect leaks in the structure in a timely manner and ensure the elimination of the defect promptly.

It is advantageous to install permanent inert gas distribution in the heat storage tank to allow for operational replenishment or replacement of the gas charge to ensure maximum reliability, safety and service life of the modules.

Pressure vessels, circulation pipes, and possibly also ventilation pipes, are preferably equipped with safety valves and/or fuses that prevent the safe overpressure or underpressure of the inert gas from being exceeded, so that parts of the heat storage tank cannot be damaged.

The outer surface or even the inner surface of the heat storage parts is preferably provided with an anti-corrosion coating.

The outer surface of the heat reservoir is preferably provided with a jacket to increase ballistic resistance.

Preferably, the bases are formed by a lattice structure, which is preferably made of a corrosion-resistant material and is preferably provided with a protective coating. The lattice structure offers less resistance to wind flow, so that the floating heat storage tank is not as prone to swaying on the water surface in the base tank.

The lattice structure is preferably provided with a peripheral shell, which allows the internal space to be filled with an inert gas to limit corrosion of the lattice structure. The peripheral shell is preferably made of a corrosion-resistant material and is advantageously provided with a protective coating. However, continuous peripheral walls of the heat storage increase resistance to wind flow.

At greater depths of immersion of the float in the base tank, it is advantageous to divide the float into multiple compartments in height, which are separated from each other by a pressure partition, preferably in the shape of a domed bottom.

Each float section, also known as a segment, is filled with gas, preferably to an internal overpressure that equals as much as possible the external overpressure of water corresponding to the greatest immersion depth of the segment in the base tank.

With increasing depth of placement, the segments are filled with gas to a higher internal pressure, which is balanced by the external water pressure, and the wall thickness of the segments can be significantly smaller than if there was a uniform internal pressure throughout the float corresponding to the maximum immersion depth of the float in the base tank. This further significantly reduces the weight of the float.

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It is advantageous to create transfer pressure chambers in the upper floors of the segments to allow maintenance workers to enter segments with different gas pressures. The chambers must be equipped with reliable closures that prevent the passage of gas with different pressure between the segments.

The depth of the basic reservoirs, especially those of natural origin, is not uniform. Since the bottom of the basic reservoir usually slopes gradually to the greatest depth in one or more places of its surface, the depth levels of greater depths occupy a smaller area than the depth levels of shallower depths.

Similarly, the bearing capacity of the subsoil will probably not be uniform over the entire area of the modular heat storage tank.

In order to achieve the greatest possible capacity, it is advantageous to make the best use of not only the area of the land of the modular heat storage facility, but also the depth of the base tank, or the bearing capacity of the subsoil, for the purposes of the modular heat storage facility.

The modular heat storage tank can be advantageously assembled from modules with a uniform height according to the smallest selected depth level in the base tank, or according to the smallest bearing capacity of the subsoil in the area of the modular heat storage tank.

The deeper the level chosen for deeper immersion of the floats, the smaller the floating modular heat storage tank will occupy in the base tank.

However, as the area of the floating modular heat storage tank decreases according to the selected depth level and the depth increases, the stability of the floating modular heat storage tank decreases, which must therefore have a smaller height, which can adversely increase the specific price and investment requirements of the floating modular heat storage tank in relation to the thermal capacity in CZK/kWh.

All circulation units in this modular heat storage tank have the same hydrostatic head and, if they are ideally of the same performance, can be replaced, for example, when regulating the total performance or in the event of a fault.

The modular heat storage tank can be advantageously assembled from modules with different heights according to the depth profile of the base tank, or according to the different bearing capacity of the subsoil in the area of the modular heat storage tank.

A heat storage tank with modules of different heights according to depth levels or according to the bearing capacity of the subsoil may advantageously comprise storage tanks of different heights according to depth levels or bearing capacity of the subsoil, with the bases having a uniform height.

In order to increase the capacity of the modular heat storage system, not only the area of the base tank or land is better utilized, but also the depth of the base tank or the different bearing capacity of the subsoil.

This design allows the axis of the center of gravity of the modular heat storage to always be identical to the axis of buoyancy of a floating modular heat storage, or to the axis of the center of gravity of the bearing capacity of the subsoil in the case of a stable modular heat storage.

This fact, together with the large width of the modular heat storage, makes it possible to ensure its stability even with a large module height.

In terms of ensuring stability against overturning, the module assembly for a fixed heat storage tank does not need to be as wide as for a floating heat storage tank, because the subsoil is much less pliable than water.

For each group of modules with the same height, a corresponding circulation unit or group of circulation units with the same hydrostatic height is preferably available.

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Preferably, in a floating modular heat storage tank, the height of the storage tanks in the modules is the same for all depth levels, but their horizontal cross-section is different, with the mutual ratio of the horizontal cross-sections of the storage tanks in the modules being equal to the mutual ratio of the float dips in these modules.

Similarly, in a stable modular heat storage tank, the height of the storage tanks in the modules is preferably the same for all subsoil bearing capacities, but their horizontal cross-section is different, with the mutual ratio of the horizontal cross-sections of the storage tanks in the modules being equal to the mutual ratio of the subsoil bearing capacities of these modules.

A heat storage tank of this design with modules of different heights according to depth levels or bearing capacity of the subsoil can advantageously contain storage tanks of the same height, while the base heights are the same and the hydrostatic head is the same for all modules. The modules differ only in the immersion depth of the floats or the bearing capacity of the foundations and the diameter of the storage tanks.

Therefore, all storage tanks in the entire heat storage system can be connected by a common circulation pipe.

Water circulation can be carried out using any circulation unit regardless of the diameter of the storage tank, a uniform type of circulation units can be used and the demands on coordination and regulation of their operation will be reduced.

Advantageously, the diameter of the pedestals can also be the same as the diameter of the storage tanks with a reduced diameter, thereby structurally simplifying the load transfer between them.

Since the diameter of the floats and the spacing between the modules remain the same, the reinforcements between the storage tanks, or between the bases of smaller diameter, must have a greater width and thickness in order to bridge the distance between the modules and to ensure the rigidity of the mutual connection of the modules.

The floating modular heat storage tank may advantageously comprise a continuous bottom of the float space.

Preferably, the continuous bottom of the floating modular heat storage tank is formed in such a way that the spaces between the floats of the individual modules are closed by domed bottoms at the level of their lower bottoms; preferably, the same material from which the floats are made is used to close the given spaces.

This modification uses the water space of the base tank between the floats of the floating modular heat storage tank to increase the volume of the gas space of the floats of the floating modular heat storage tank, thereby increasing the buoyancy of the float part of the floating modular heat storage tank.

The side walls of the module system in the area of the floats will preferably be protected against the effects of water in the base tank, where salt water in particular has particularly strong corrosive effects.

It is also advantageous to close the space between the floats, or possibly between their segments, at the level of their upper ends.

Then this single-part or multi-part space, i.e. segments, between the floats can be filled with the same internal pressure of gas, preferably inert, as the space inside the floats or segments, thereby equalizing the external and internal pressures on the side walls of the floats or segments and also on the bottoms of the floats.

The bottoms of the floats and the vertical walls of the floats in the peripheral modules can be advantageously made of a corrosion-resistant material, the walls of the floats in the modules in the interior of the floating modular heat storage tank can be made of a cheaper material, which reduces the price of the floating modular heat storage tank.

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In a system of modules, it is advantageous to create a continuous bottom for the storage tanks by closing the space between the storage tanks at the level of the lower bottoms and then using this space to fill with water.

It is advantageous to create a continuous bottom for storage tanks by closing the space between the storage tanks at the level of the upper bottoms. Then the space above the water surface can also be filled with a protective atmosphere, similar to the inside of the storage tanks.

It is advantageous to equip the spaces between the floats and storage tanks with ventilation pipes and further secure them like the floats and storage tanks themselves.

By using the space between the floats to increase their buoyancy and the space between the storage tanks to fill with water, the efficiency of using the bearing capacity of the subsoil or the space of the base tank on the surface of the heat storage tank will significantly increase, and thus the capacity of the heat storage tank for heat storage, without impairing its stability.

When using a structure of modules connected to each other by vertical stiffeners, the storage tanks must also be reinforced with internal vertical stiffeners and the vertical stiffeners between the peripheral storage tanks must be strengthened to withstand the one-sided load from the hydrostatic pressure of water between the modules.

In this design, individual modules or the gaps between them cannot be operated differently from other modules, e.g. in the event of a module failure, because inadmissible mechanical stress would arise in the module walls and vertical reinforcements with different loads due to hydrostatic water pressure.

The spacing of the storage tanks or modules is preferably equal to their diameter. The storage tanks or modules are preferably connected to each other directly by their walls. The connection of the walls is preferably carried out using connecting components, preferably using screws or rivets. The connection of the walls is preferably carried out using spot or line welds.

Compared to connecting modules with vertical stiffeners, the advantage here is better use of the heat storage space for heat storage purposes, better use of the bearing capacity of the subsoil and the space of the base tank on the surface of the heat storage, without impairing its stability.

This type of construction will allow for a reduction in specific material costs compared to the construction of modules with vertical stiffeners and can further simplify part production and assembly.

However, access to the joints is only possible from the interior of the modules. The interior surface of the module walls can be inspected over the entire area, the exterior surface of the module walls can only be inspected in part, because the module walls are close together in the joint area and access to the space between the modules is quite difficult.

Using the space between the storage tanks to fill with water is only possible at the cost of reinforcing the internal space of the storage tanks with vertical reinforcements across the entire diameter.

The spacing of the storage tanks or modules is preferably smaller than their diameter. The system of storage tanks or modules of the heat storage is then advantageously composed of vertical modules that are interconnected, intersecting each other in plan, thereby creating a mutual connection, preferably in a triangle, without the need for external or internal vertical stiffeners or other types of reinforcement of the vertical joints between the modules. The interconnected walls of the storage tanks or modules are connected by means of welds.

The connection of modules, or rather a system of modules, is carried out by welding lens-shaped segments assembled from curved sheet metal arcs. For example, when assembling modules into triangular connections, each arc is 1/6 of the circumference of the module cross-section.

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The entire space of the module system is used for heat storage purposes, the bearing capacity of the subsoil or the space of the base tank on the surface of the heat storage tank is fully utilized, without impairing its stability.

This type of construction will allow for a reduction in specific material costs compared to the construction of modules with vertical stiffeners and can further simplify the production of parts and the assembly of the heat storage.

Depending on the ratio of the diameter and pitch of the modules, the connection of the modules has a different shape and various advantages and disadvantages.

If the module walls intersect at one point, the module wall welds are concentrated at this one point, which is disadvantageous for ensuring the quality of the welds.

In order to reduce the thermal load on the welded area and improve the quality of the welds, it is advantageous to choose the module spacing so that only two module walls intersect at one point. This can be achieved by increasing or decreasing the module spacing. When the module spacing is increased compared to the diameter, the wall overlap decreases and the space between them is less accessible for inspection of the inner walls of the modules, the rigidity of the module system is lower, but the use of the module material per unit area of the module system is more advantageous. When the module spacing is reduced compared to the diameter, the wall overlap increases and the space between them is better accessible for inspection of the inner walls of the modules, the rigidity of the module system is higher, but the use of the module material per unit area of the module system is less advantageous.

There is the possibility of operating individual modules or shutting them down in the event of a failure independently of the other modules, without dangerous loads occurring in the walls of the other modules due to different lateral hydrostatic water pressure.

Preferably, each space created by connecting the modules is connected by a closable branch to the circulation pipe and thus to the circulation unit. In addition to connecting the internal space of the storage tank, it is necessary to create additional connections to the spaces created by connecting the modules. This increases the total number of branches of the circulation pipe.

In order to maximize the space utilization of a system of modules with different diameters of storage tanks, it may be advantageous to connect part of the storage tanks and entire modules with a larger diameter by connecting the walls and part of the storage tanks and entire modules with a smaller diameter by connecting the stiffeners.

The lower bottoms of the floats, or their segments, are preferably provided with openings with closures for the possibility of flooding the internal space of the floats to align the position of the floating heat storage tank, e.g. during module assembly, during repairs or when resolving a malfunction of the floating heat storage tank.

To quickly flood the floats in the event of an accident, the bottoms of the floats, or segments, are preferably equipped with pressure fuses.

For heat transfer by the heat transfer fluid in the heat storage tank, a circulation pipe with a circulation pump (for liquids) or a circulation compressor (for gases) is preferably used, which overcomes hydraulic resistance during the flow of the heat transfer fluid in the circulation pipe.

Liquid flows in a fluid pipe, water flows in a water pipe, gas flows in a gas pipe, and air flows in an air pipe.

Hot water has a lower density and therefore rises to the top of the storage tank. This fact is advantageously used in the arrangement of the circulation pipes to achieve the best possible heat transfer efficiency in the heat storage tank.

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The circulation pipe in the heat storage tank is preferably designed so that the ends of the circulation pipe are immersed in the heat transfer fluid in the storage tank. The circulation pipe connects the spaces of the storage tank containing the heat transfer fluid without interrupting the fluid column through space with another fluid (or immediately, directly, continuously), so that the fluid flow is continuous.

The circulation pipe for supplying heat to the storage tank is preferably arranged so that the branch of the circulation pipe for drawing off cooled water is located in the lower part of the storage tank, and the branch of the circulation pipe for supplying heated water is located in the upper part of the storage tank.

The circulation pipe for taking heat from the storage tank is preferably arranged so that the branch of the circulation pipe for supplying cooled water is located in the lower part of the storage tank, the branch of the circulation pipe for taking heated water is located in the upper part of the storage tank.

In the heat storage tank, the circulation pipe preferably has a rectangular configuration and thus has a vertical and a horizontal part.

The vertical part of the circulation pipe can be located inside or outside the storage tank.

Preferably, each storage tank is equipped with a separate circulation pipe. In this case, only one valve in the circulation pipe is sufficient to regulate the flow.

Preferably, a pipe branch is connected to the bottom of each storage tank to a horizontal part of the circulation pipe, i.e. to the collecting circulation pipe, which forms the pipe network below the storage tanks.

Preferably, storage tanks with the same hydrostatic head in a group of adjacent modules are connected in this way. The group of adjacent modules has one common circulation unit available. The pipe branch at each storage tank is preferably equipped with a shut-off valve so that the flow rate and water level in each storage tank can be reliably controlled.

Preferably, all storage tanks in modules with the same hydrostatic height are connected by a collecting circulation pipe, with the given horizontal network of collecting circulation pipes being connected to a circulation unit preferably located around the perimeter of the module system.

Here too, the pipe branch at each storage tank will preferably be equipped with a shut-off valve so that the flow rate and water level in each storage tank can be reliably regulated.

Preferably, from each separate liquid space, i.e. from each storage tank and from each space between them, a circulation pipe is led to the periphery of the heat storage tank and is equipped with a closure.

The vertical circulation pipe may advantageously be located at the circuit modules, preferably at each circuit module.

Preferably, the horizontal and/or vertical circulation pipe is formed from several parallel runs in order to reduce the diameter, wall thickness and weight of each run of the circulation pipe, which will increase the overall hydraulic losses but will facilitate the production, transport, installation and maintenance of the circulation pipe.

The vertical circulation pipe may have a wall thickness graded along its height according to the static and dynamic water pressure.

The spaces between the storage tanks created by connecting the modules can be connected to the spaces inside the modules using various pipe or hole options.

-23 CZ 38598 UI

However, due to the circular shape of the storage tanks, when draining or filling individual storage tanks, e.g. due to a malfunction, it is necessary to follow a procedure for shutting down or filling adjacent storage tanks so that all storage tanks are only loaded with internal overpressure.

In a heat storage tank, the walls of the storage tanks between the modules preferably contain flow openings that can serve as a supplement or alternative to the circulation pipe, which is particularly advantageous for storage tanks that have the same height.

When filled with water, the storage tank spaces form connected containers and for circulation pumping, a common circulation pipe, which is connected to the side of the storage tanks, is sufficient; a horizontal collecting circulation pipe does not need to be installed.

The common circulation pipe is then preferably connected to a circulation unit located on the periphery of the module system.

The flow openings are only accessible after all storage tanks have been emptied.

Preferably, these openings are equipped with valves, preferably control valves, preferably remotely controlled valves. The valves have control elements led into the space under the storage tanks so that they are accessible at any time. This is an advantage in the event of a failure of the storage tank, which can then be shut down without the need to empty the other storage tanks.

Due to the resistance of the pumped fluid when flowing between the internal spaces, the water will not circulate evenly in these spaces. The temperature equalization between the tanks at the center and at the periphery of the tank system is worse than when each tank or each group of tanks is connected to the circulation pipe separately.

Resistance in the flow openings and thus the uneven use of storage tanks increases with increasing water flow rate.

Uneven filling or draining of storage tanks with water can generally be reduced or eliminated by throttling the air flow in the vent pipe above the water level in the storage tanks. For storage tanks that are closer to the circulation system, the need for throttling the air flow is greater. For a design of a module system with flow openings, the unevenness of the water flow will probably be greater and therefore the need for throttling the air flow will also be greater.

For this purpose, it will probably be advantageous to equip the heat storage tank with a device, preferably control valves, for regulating the air pressure above the water level in the individual storage tanks.

However, due to the increased hydrostatic water pressure and air overpressure, the storage tanks must be significantly larger in size, which increases the cost of the storage tanks.

When repairing a damaged part of a storage tank with flow openings without closures, it is necessary to empty the entire heat storage tank and the entire heat storage tank is out of operation during the repair.

In the case of a heat storage tank with closures in the flow openings between the storage tanks, a damaged storage tank can be repaired by first emptying the damaged tank and possibly also the adjacent storage tanks, e.g. by pumping water from the shut-down storage tanks into the other storage tanks or into the emergency sump, and then repairing the damaged storage tank. The other storage tanks can be used for heat storage during the repair. After the repair, the water is pumped back into the empty storage tanks and the repaired storage tank can be used again.

For repair purposes, it is therefore advantageous to leave adequate free volume in the storage tanks.

-24 CZ 38598 UI

The design of storage tanks with flow openings is particularly advantageous when storing thermal or pressure energy of gas, given that gases have a significantly lower viscosity than liquids and therefore energy losses due to gas flow in the flow openings are significantly lower.

Preferably, a gas pipe is led from each separate gas space, i.e. the float and its segment, the storage tank and the base, and the space between them, to the perimeter of the heat storage tank.

Advantageously, the gas pipeline is equipped with a separate closure for each separate gas space.

This will extend the length of the gas pipeline, but the valves can be located in a cooler space, which will significantly increase the reliability of operation of these valves and improve working conditions for operation and maintenance even at increased temperatures in the module space.

When the circulating water temperature increases, the gas temperature in the gas spaces of the heat storage tank also increases and, if these spaces are closed, the gas pressure also increases.

In order to avoid the need to burden the gas pressure vessels and gas pipelines with this increased pressure, it is advantageous to equip the heat storage with a compressor station. Here, the excess gas from the gas spaces will be compressed or even liquefied and stored in tanks, from which the gas can be withdrawn again to replenish the gas spaces of the heat storage when the temperature and thus the gas pressure drop.

To prevent the modules from deforming differently and remaining aligned to the same height level, it is necessary to fill the storage tanks proportionally in all modules.

If the storage tanks in all separate modules or groups of modules are not filled proportionally, these modules or groups of modules will not be loaded proportionally according to their load capacity and their total height will differ from each other during the filling process. Their total heights will be equalized when the filling of all storage tanks is equalized so that it is proportional, e.g. when the filling is completely completed.

In embodiments where the circulation units are located around the perimeter of the module system, it may be advantageous to run a branch of the circulation pipe from each storage tank to the perimeter of the module system and to place the closure of the branch there.

Measuring and evaluation devices from sensors at individual storage tanks can also be advantageously brought into this space.

Although the water flow losses in the circulation pipe will increase, the areas with the valves in the circulation pipe located around the perimeter of the module system can be more easily air-conditioned to create favorable conditions for the operation of the valves and measuring instruments and for the operating and maintenance personnel. The reliability and safety of the heat storage tank will thus be ensured even with an increased temperature of the stored water.

Preferably, the circulation unit is mounted on the outside of the module assembly, so that it is more accessible for maintenance.

In a floating heat storage tank, the circulation unit preferably moves in line with the storage tank, and can preferably be connected to it.

Advantageously, the circulation unit can be located outside the module system.

In the case of a floating heat storage tank, the circulation unit is preferably located in a pontoon or other floating device. The circulation unit is connected to the module system preferably by means of a sliding or articulated device, with the circulation pipe in this part preferably

-25 CZ 38598 UI of a flexible, articulated or telescopic design, which allows to compensate for mutual movements between the circulation unit and the module system, especially when the floating heat storage tank swings on the water surface in the base tank. Preferably, the circulation pipe in this part is made of plastic, preferably it is reinforced.

Since the circulation unit moves at the water level, it is more easily accessible for assembly and maintenance. The disadvantage is longer and more complex paths for heat transfer, which is associated with energy losses and possibly a shorter service life of the flexible circulation pipe.

In this context, the circulation unit can preferably be firmly connected to the base tank, preferably placed on a structure attached to the bottom of the base tank, preferably in a hollow tube, or preferably placed on the bank of the base tank.

In a stable heat storage tank, the circulation unit does not have to be connected to the module system by a fixed circulation pipe, but the circulation pipe is preferably of a flexible, articulated or telescopic design, which allows to compensate for any, in particular, thermal expansion between the circulation unit and the module system.

By placing the circulation unit outside the module system, it is generally easier to access for assembly, operation and maintenance, and its size can also be better optimized. By increasing the capacity of the circulation units, their number could be reduced, of course taking into account the requirements for heat transfer control.

The heat storage tank is preferably arranged so that the circulation unit is located in the machine room outside the module system; its noise insulation can then be addressed more effectively than when placed in a sheet metal module system.

Further sound insulation can be achieved by partially or fully locating the engine room with the circulation system below ground level or below the water level in the base tank.

In a floating heat storage tank, the circulation units, preferably with the corresponding circulation piping, are preferably located in energy modules connected to the modules around the perimeter of the floating heat storage tank, so that balancing the modules and accessibility of the circulation units for assembly and maintenance can be more easily resolved.

The heat storage tank, in particular the circulation units and the circulation pipeline, preferably also includes other usual accessories, in particular devices for damping hydraulic shocks in the circulation pipeline.

The transmission of electrical energy between the circulating system and the electrical equipment on the bank of the base reservoir can be advantageously solved with a movable cable.

Tall storage tanks require a large wall thickness, which increases their price.

Therefore, it may be advantageous to create several storage tanks with a smaller construction height and thus a smaller wall thickness instead and place them one above the other, separated in height by a pedestal.

The heat storage tank can thus be arranged in several levels one above the other, with each level consisting of a layer of storage tanks or a layer of pedestals with storage tanks.

The heat storage tank may advantageously comprise a separate circulation unit or a set of circulation units for each floor.

This arrangement of storage tanks increases the required length of the circulation pipe, which may, however, have a smaller diameter due to the lower flow rate.

-26 CZ 38598 UI

The storage tanks on each floor are preferably ventilated by a separate ventilation pipe.

In floors without a base, the vertical circulation and ventilation pipes are routed through the space between the storage tanks or inside the storage tanks. In this arrangement, access to the pipes is somewhat complicated for maintenance and operation.

The floating heat storage tank preferably includes a device for defining the position on the water surface in the base tank.

The floating heat storage tank contains, for example, anchoring ropes or rods that are fixed to the shore of the base tank and allow for the necessary expansion to prevent parts of the floating heat storage tank and anchoring elements from being overloaded by uneven loading, for example due to strong winds while the floating heat storage tank is rocking.

The floating heat storage tank is preferably secured on the surface of the base tank by a guide frame that surrounds the floating heat storage tank around its entire circumference.

The guide frame preferably has a floating part and an anchoring part which are hingedly connected to each other. The anchoring part is preferably hingedly attached to the foundations on the bank of the base tank.

The guide frame serves primarily to stabilize the floating heat storage tank against horizontal movement on the water surface in the base tank, allows vertical movement and free swinging of the floating heat storage tank and is anchored to the bank of the base tank in such a way as to enable the proper functioning of the floating heat storage tank within the permissible height changes of the water level in the base tank.

The guide frame is preferably equipped with a spring-loaded wheel guide and a rigid guide to stabilize the floating heat storage tank against horizontal movement on the water surface in the base tank and to guide the floating heat storage tank during vertical movement.

The floating heat storage tank preferably includes at least one access path for walking of operating and maintenance personnel and for the associated transport of material, e.g. between the bank of the base tank and the floating heat storage tank, as well as for other purposes.

Preferably, the access path is formed on the anchoring part and/or on the floating part of the guide frame.

Preferably, the access road includes a connecting bridge.

The floating heat storage tank is preferably equipped with a working platform, which is preferably formed on a guide frame.

The access path is preferably part of the working platform.

A work platform has the advantage of serving multiple purposes:

- as an access route for service and maintenance personnel;

- as a transport route for transporting material using transport equipment during maintenance and repairs, especially of closures and circulation units;

- as an assembly platform during maintenance and assembly of the floating heat storage tank;

- for carrying and routing cables to circulation units, to control and regulating fittings, to measuring and safety instruments and devices;

- for carrying auxiliary electrical equipment and distribution (outdoor and indoor assembly equipment for lifting loads and transporting people, lighting, connections for powering electrical tools and devices, defrosting in winter);

- for carrying inert gas distribution for filling modules.

-27 CZ 38598 UI

The work platform is advantageously equipped with:

- a railing with edges at the floor to prevent people and objects from falling from the guide frame into the water;

- tracks for rail transport of cargo and materials;

- winches for pulling rail vehicles on rails;

- lighting;

- safety equipment and means for rescuing people from falling from the guide frame into the water (lifeboats and belts);

- anchoring, handling and access equipment for transferring material and people between the guide frame and watercraft.

The working platform is preferably firmly connected to the perimeter of the floating heat storage tank.

This working platform is preferably situated in height so that it exceeds the water level in the base tank during rocking even in strong winds, and is preferably created at the level of the circulation units.

This working platform is preferably connected by connecting bridges to the bank of the base reservoir.

The connecting bridge is preferably hingedly connected to the floating heat storage tank and slidably connected to the bank of the base tank.

The heat storage tank preferably includes access and transport routes, preferably work platforms, for the horizontal transport of people and materials for assembly, operation and maintenance, to the circulation units and to the pipelines.

Horizontal work platforms are preferably formed below and above the storage tanks.

The heat storage tank preferably includes access and transport routes for vertical transport of people and materials for assembly, operation and maintenance to the circulation units, to the vertical and horizontal circulation pipes and to the work platforms.

For inspection, cleaning and repair of modules from the inside and outside, it is advantageous to create closable inspection openings in the upper or lower bottoms, or in the side walls or horizontal reinforcement flanges or in platforms at storage tanks, pedestals and floats, which will allow workers to enter and use the necessary work equipment and devices.

In the pedestal area, elevated temperatures may occur despite the insulation of the tanks, therefore the pedestal area around the perimeter of the module system is preferably equipped with fans, which can be used to ventilate the necessary access routes so that they are accessible to operating and maintenance personnel.

For this purpose, it is advantageous to provide the inspection openings with closing partitions or doors with remote control. In the event of repairs at a certain point within the module system, only those inspection openings will be opened that create an access path to the repair point and this path can then be quickly ventilated by the nearest fans. After the repair is completed, the inspection openings will be closed again to prevent unnecessary heat loss from the heat storage.

For vertical transport, a rope or rack transport device is preferably used.

The rope transport device may preferably be a friction disc drive or a drum drive.

A device for vertical transport of people and goods is preferably installed inside and/or outside the peripheral modules, preferably this device is a suspended or climbing assembly platform.

A large multi-purpose work platform can then be created on a system of modules.

-28 CZ 38598 UI

This simplifies access to all modules and facilitates assembly and maintenance work on the module system.

Since a heat storage tank can generally have a large surface area and its structure can reach high above the surrounding terrain, a solar and/or wind power plant can be advantageously located on its upper platform or even on its vertical peripheral walls.

The electrical energy produced in this solar or wind power plant can be advantageously used to heat water directly in the heat storage tank.

The side walls and upper platform of the heat storage can also be used for other purposes, for example for housing, for sports and recreational activities, as an observation tower or for advertising purposes.

However, it is necessary to consider that any added load on the heat storage tank must also respect the load-bearing capacity of the foundations or floats and may therefore mean a partial limitation of the storage capacity of the heat storage tank.

The heat storage tank will change its volume due to changing temperatures.

Height changes of the heat storage tank are not a problem.

Surface changes in the dimensions of individual parts of both floating and fixed heat storage tanks due to temperature changes must be compensated for, as the storage tanks will usually be thermally insulated better than other parts of the heat storage tank.

Temperature changes without compensation will cause stress imbalances in the structure of the module system.

With a stable heat storage tank, horizontal movement of the foundations to ensure expansion of the module system can only be addressed with difficulty.

It will therefore be advantageous to create a stable modular heat storage system from groups of modules with separate foundations, these groups of foundations being preferably connected by expansion elements, these groups of modules being preferably connected by stiffeners that allow for thermal expansion between the groups of modules.

Individual groups of modules can then easily tolerate different subsidences of the subsoil and no mechanical tension will arise between them for this reason. However, in the event of uneven subsidence of the subsoil, the groups of modules will tilt and it will be necessary to rectify them in a timely manner.

The system of interlacing modules is relatively elastically compressible in the horizontal plane, so it will not be necessary to divide it into groups of modules or these groups can contain a larger number of modules. With a small change in temperature, the shape of the modules will then adapt elastically without damaging the mounting of the modules on the foundations.

In the event of major temperature changes in the module system, the modules can be lifted permanently or only when the temperature changes using lifting bags located in the rectification area. These lifting bags allow not only axial, i.e. vertical, deviations to be compensated, but also lateral deviations, so that they allow a prompt response to temperature changes in the modules and to compensate for dimensional changes in the module system in order to prevent deformations and collapse of the module walls.

When the water in the heat storage tank is heated evenly, the changes in the position of the modules will add up and therefore increase from the center of the module system towards its periphery. The module system must therefore be secured against unwanted overall one-sided shifting on foundations, for example

-29 CZ 38598 UI by securing the modules in the center of the module system against position changes. The other modules will be able to expand freely on the lifting bags around the center of the module system.

If the lateral change in the position of the modules during expansion of the module system is greater than the permissible lateral deviation of the lifting bags, the module system will be placed on the foundations by venting the lifting bags, the lifting bags will be released, thereby leveling them, and when the lifting bags are further pressurized, the module system will be lifted again and its expansion can continue.

The heat storage preferably includes a monitoring, measuring and control system that ensures safe operation of the heat storage based on the measurement of important operating variables and their comparison with permissible values. The system is preferably automatic and automatically makes the necessary changes to the heat storage parameters.

The heat storage tank can advantageously be assembled in layers, each layer by successive assembly and connection of individual module parts next to each other.

The floating heat storage tank can thus be assembled directly on the water surface in the base tank, i.e. without the help of an assembly dock.

Additional layers are gradually connected to the lowest layer of module parts so that the entire heat storage is balanced on the subsoil or on the surface of the basic tank during construction and no unnecessary additional mechanical stresses arise in it. First, the foundations, or rather floats, are assembled, then the bases are layered on them, and finally the storage tanks. Accessories are also continuously installed, especially the circulation and ventilation pipes and circulation units.

At the same time, it is necessary to build a water supply for filling the storage tanks of the heat storage, as well as equipment for supplying heat to the heat storage and equipment for removing heat from the heat storage to the consumer.

The floats in a floating heat storage tank assembled from modules of different heights are preferably assembled in such a way that the base layer of floats with the greatest immersion depth, which have the greatest structural height, is assembled first.

After the basic layer of floats is completed, the floats are immersed by connecting another layer of floats, or pedestals or storage tanks (only to the extent that the stability of the assembled part on the water surface in the basic tank is not impaired) or by partially filling the lower part of the floats or storage tanks with water so that floats with a smaller construction height can be connected to them at the required level. After the assembly of the new layer of floats is completed, the floats are further immersed using the same procedure so that floats with a smaller construction height can be connected to them at the required level. This continues until the floats with the smallest construction height are connected, after which the entire connected group of floats is further immersed so that further assembly can continue by evenly connecting the next higher layers, i.e. pedestals and storage tanks, proportionally so that additional mechanical stresses do not occur.

The upper part of the floats or their segments, which will not be flooded, will be gradually filled with compressed gas so that the external hydrostatic pressure of the water is constantly compensated in the floats and the floats do not collapse.

During further assembly, the weight of the floating heat storage tank will increase, as it will continuously submerge, gradually displacing water from the base tank in a volume that corresponds to the displacement of the empty floating heat storage tank.

The entire amount of water can be retained in the internal space of the floats during installation, which will be pumped into the storage tanks above the floats after the installation of the floating heat storage tank is completed, making it immediately available for heat storage, without the need to pump water.

-30CZ 38598 UI additional water from the base tank. Water transfer from the floats can be advantageously carried out via an auxiliary pipeline by suction using built-in circulation units and also by extrusion using compressed gas, which will compensate for the external hydrostatic pressure of water inside the floats against collapse of the floats or segments.

The construction of the heat storage tank is resistant to adverse weather conditions and earthquakes, especially with a greater usable depth or bearing capacity of the subsoil.

Despite its large dimensions, the floating heat storage tank does not increase the weight load on the base tank subsoil.

The load on the subsoil with a stable heat storage tank increases, but remains constant during heat storage.

Although steel production and transport during the construction of a heat storage tank are energy-intensive, due to the long service life of the heat storage tank, its carbon footprint is relatively insignificant.

Compared to previous solutions, the heat storage tank shows an all-round improvement in parameters and other useful properties.

In a floating heat storage tank, part of the heat is transferred to the water in the lake or to the subsoil through the walls of the heat storage tank, especially through the floats, which are heated by heat transfer from the supported storage tanks and pipes.

It is advantageous to strengthen the thermal insulation of the storage tank system to prevent unwanted heating of the water in the base tank.

The walls of the pedestals below the storage tanks of the heat storage tank floating in the base tank are preferably provided with additional heat exchange fins in the part above the water level in the base tank, through which the heat that passes from the insulated storage tank system is discharged into the ambient air, thereby reducing the amount of heat transferred to the water in the base tank.

The disadvantage of a floating heat storage tank is that heating the lake water can endanger the biological balance in the lake. In addition, there is increased evaporation and thickening of the lake water, which must be replenished at an increased rate from the flowing water stream.

On the other hand, heating the water in the base tank can be an advantage in winter, when it reduces the risk of freezing of the water in the base tank and in the surrounding terrain. It can also be advantageous to use the base tank for recreational purposes or for year-round production of fish or plants.

Since the heat storage tank does not have special requirements for the bearing capacity of the subsoil or the depth of water in the base tank, it can be advantageously located near the heated agglomeration or directly on its premises, which shortens the length of the heating circulation pipe and reduces the price of the supplied heat.

Land from former industrial enterprises can be used very effectively for the construction of a heat storage facility, also because they usually have a higher bearing capacity of the subsoil, which is advantageous for increasing the thermal capacity of the heat storage facility by increasing the height of its storage tanks.

Placing a stable heat storage tank partially or fully below ground level is advantageous in that it does not protrude so much above the surrounding terrain, so it does not cause a disturbance to nearby housing estates. The disadvantage may be the complexity of the excavation work.

The capacity and performance of the heat storage can be dimensioned according to the size and needs of the heated agglomeration.

-31 CZ 38598 UI

Heat can be supplied to the heat storage tank from any energy sources, e.g. from waste heat sources.

The heat storage tank can be heated by a heating element, preferably by solar or wind power plants, at times when they will not have a favorable consumption of electrical energy, which will increase the efficiency of their operation.

In particular, excess generated electrical energy can be stored in the heat storage tank.

A heat source that must be operated at a constant output all year round because its regulation is lossy, such as a coal-fired or nuclear power plant, can be used for a heat storage tank. The heat storage tank increases the efficiency of this heat source by increasing its base load. The heat source for the heat storage tank can then be built with a lower output, but will be operated evenly throughout the year, so that it will produce heat more cheaply and the overall cost of heat for heating will also be reduced.

A heat storage tank allows you to store heat cheaply for daily and seasonal use.

Clarification of drawings

The technical solution will be explained in more detail using examples of implementation according to the attached drawings, which show:

Fig. 1 shows a diagram of a single-storey module of a stable heat storage system;

Fig. 2 shows a diagram of a two-story stable heat storage module;

Fig. 3 shows a diagram of a single-storey floating heat storage module;

Fig. 4 shows a diagram of a two-story floating heat storage module;

Fig. 5a and 5b show a comparison of the floating of a floating heat storage module with a one-piece and a three-piece float;

Fig. 6 shows a diagram of a stable heat storage module with a rectification device;

Fig. 7a, 7b and 7c show a diagram of a system of interconnected heat storage modules in three variants;

Fig. 8a and 8b show a diagram of storage tanks in a system of interconnected heat storage modules;

Fig. 9 shows a diagram of a floating heat storage tank with a single-level module system;

Fig. 10 shows a diagram of a floating heat storage tank with a three-level module system;

Fig. 11 shows a diagram of a stable heat storage system with a three-level module system;

Fig. 12a, 12b and 12c show a diagram of a floating heat storage tank;

Fig. 13 shows a diagram of a planar system of interconnected modules;

Fig. 14 shows a diagram of a system of interconnected modules on a wavy subsoil;

Fig. 15 shows a diagram of a system of interconnected modules on a wavy subsoil and with the same height of pedestals;

Fig. 16 shows a diagram of a system of interconnected modules on a wavy subsoil and with the same height of tanks;

Fig. 17a and 17b show diagrams of two variants of a floating heat storage tank with a system of modules with different diameters;

Fig. 18a and 18b show diagrams of two variants of a floating heat storage tank with a system of modules of different diameters and with a gas-tight casing;

Fig. 19a and 19b show diagrams of two variants of a stable heat storage tank with a system of modules of different diameters and with a gas-tight casing;

Fig. 20 shows a diagram of a system of interconnected modules with parallel connection of the circulation pipe;

Fig. 21 shows a diagram of a system of interconnected modules with independent connection of the circulation pipe;

-32CZ 38598 UI Fig. 22 shows a diagram of a modular heat storage tank with a heat supply device and a heat withdrawal device;

Fig. 23 shows a diagram of a modular heat storage tank with a heat supply device and a heat withdrawal device;

Fig. 24 shows a diagram of a modular heat storage tank with a heat supply device and a heat withdrawal device;

Fig. 25 shows a diagram of a modular heat storage tank with a heat supply device and a heat withdrawal device;

Fig. 26 shows a diagram of a modular heat storage tank with a heat supply device and a heat withdrawal device;

Fig. 27 shows a diagram of a modular heat storage tank without pedestals, with thermal insulation and a gas-tight casing;

Fig. 28 shows a diagram of a modular heat storage tank with pedestals, thermal insulation and a gas-tight casing.

Examples of implementing a technical solution

A diagram of a single-storey module of a stable heat storage system is shown in Fig. 1. Module 7 has two basic parts:

- a storage tank 12. which serves to carry the water filling, is loaded mainly by the internal excess water pressure; and

- pedestal 11, which serves to support the storage tank 12, is built on a foundation 9 formed in the subsoil 3 and is loaded mainly by the vertical weight of the supported parts, i.e. mainly by the storage tank 12.

The storage tank 12 with a height of N is filled with water. The pedestal 11 must have a height M sufficient for the placement of the circulation pipeline with valves and the working platform and for the walking of the operating and maintenance workers. The floor is formed by the pedestal 11 and the supported storage tank 12. The foundation 9 serves to support the pedestal 11 with the storage tank 12 and is placed on the subgrade 3, it is loaded mainly by the vertical weight of the supported parts. The upper level of the foundation 9 is created above the terrain level 4, in order to be able to drain the space of the module 7 well in the event of a failure of the storage tank 12 or the circulation pipeline.

Fig. 2 shows a diagram of a two-storey module of a stable heat storage. A module 7 is built on a base 9, which consists of two floors above each other, each floor consisting of a base 11 and a supported storage tank 12. Due to the lower hydrostatic pressure of water in the storage tanks 12, the thickness of the walls of the storage tanks 12 may be smaller than that of the storage tank 12 in Fig. 1, the sum of the heights N of both storage tanks 12 may therefore be greater than the height N of the storage tank 12 in Fig. 1. When optimizing the use of material, it is necessary to consider the weight of the bottom of the storage tanks 12 and the weight of the bases 11.

A diagram of a single-storey floating heat storage module is shown in Fig. 3. Module 7 has three basic parts:

- a storage tank 12. which serves to carry the water filling, is loaded mainly by the internal overpressure of water;

- the pedestal 11, which serves to support the storage tank 12, is built on the float 10. It is loaded mainly by the vertical weight from the supported parts, i.e. mainly from the storage tank 12; and

- float 10. which serves to support the base 11 with the storage tank 12 and is immersed in water in the base tank 1, thereby creating the necessary buoyancy, is loaded mainly by the external excess pressure of water and the vertical weight of the supported parts. The storage tank 12, the base 11 and the float JO are made of thin sheet metal and their horizontal cross-section has a circular shape. The base 11 has a wall thickness t. The storage tank 12 with a height N is filled with water. The base 11 must have a height M sufficient for the placement of the circulation pipeline with valves and the working platform and for the walking of the operating and maintenance workers. The float JO is immersed to a depth H and has a total height P, which is higher than the depth H, in order to ensure the safety of the float 10 against sinking below the water level 13 in the base tank 1

-33 CZ 38598 UI under the influence of random static and dynamic loads and to enable good drainage of the module 7 space in the event of a failure of the storage tank 12 or the circulation pipe.

Fig. 4 shows a diagram of a two-storey module of a floating heat storage tank. The module 7 contains a float 10 which floats in the water in the base tank 1, so that the upper edge of the float 10 extends above the water level 13 in the base tank 1, two floors are placed on the float 10 one above the other, each floor being formed by a base 11 with a supported storage tank 12.

Fig. 5a and 5b show a comparison of the floating of the module of the floating heat storage tank with a one-piece and a three-piece float. Fig. 5a shows a diagram of the floating of the module of the floating heat storage tank with a one-piece float 10. The module 7 contains a storage tank 12. a base 11 and a one-piece float 10. which are made of thin sheet metal and their horizontal cross-section has a circular shape. The intermediate piece 11 has a wall thickness t. Fig. 5b shows a diagram of the floating of the module of the floating heat storage tank with a three-piece float. The module 7 contains a storage tank 12. a base 11 and a three-piece float 10. The float 10 contains sections 10a. 10b. 10c (segments) which are made of thin sheet metal of thickness t and their horizontal cross-section has a circular shape. The individual sections 10a. 10b. 10c of the float JO are filled with air with an overpressure equal to the greatest hydrostatic pressure of water to which the given section 10a. 10b. 10c of the float 10 is exposed when fully immersed in the base tank 1, i.e. the sections 10a. 10b. 10c of the float 10 located deeper are filled with air with a higher overpressure. The upper bottom of the lower section 10a serves as a pressure barrier between the lower section 10a and the middle section 10b. The upper bottom of the middle section 10b serves as a pressure barrier between the middle section 10b and the upper section 10c.

As a result of better balancing of the internal gas pressure with the external hydrostatic water pressure, this three-part float 10 can therefore have thinner walls and therefore less weight than a one-part float 10 with the same height, i.e. with the same buoyancy. The storage tank 12 can therefore be higher than in the module 7 with a one-part float 10 according to Fig. 5a. When optimizing the use of material, it is also necessary to consider the weight of the float 10.

Fig. 6 shows a diagram of a stable heat storage module with a rectification device. A foundation 9 is built in the subsoil 3, on which a pedestal 11 is placed. A storage tank 12 is placed on the pedestal 11. A rectification space 29 is created in the lower part of the pedestal 11 for rectifying the position of the module 7 on the base 9, in such a way that the lower part of the pedestal 11 under the storage tank 12 is provided with a horizontal reinforcement and mounting holes in the walls of the pedestal JI. Pneumatic lifting bags 30 are inserted into the rectification space 29 between the horizontal reinforcement and the base 9 through the mounting holes, and by filling the lifting bags 30 with air, the module 7 can be lifted. A pad with a thickness determined according to the measurement results can be inserted into the resulting gap between the module 7 and the base 9, and by releasing the air from the lifting bags 30, the module 7 can be lowered onto the base 9 with the pad again.

Fig. 7a, 7b and 7c show a diagram of a system of interconnected heat storage modules in three variants. The system of 6 modules contains modules 7 with a circular horizontal cross-section, which are interconnected into a triangle, while the pitch A of the modules 7 is smaller than their diameter D, therefore they overlap in plan view with an overlap B. In Fig. 7a, it is evident from detail C that the pitch A of the modules 7 is chosen so that the walls of all three modules 7 intersect at one point. In Fig. 7b, it is evident from detail C that the pitch A of the modules 7 is larger than in the variant according to Fig. 7a, therefore only two walls of the modules 7 intersect at one point. The overlap B of the modules 7 is smaller. In Fig. 7c, it is evident from detail C that the pitch A of the modules 7 is smaller than in the variant according to Fig. 7a, therefore only two walls of the modules 7 intersect at one point. The overlap B of the modules 7 is larger.

Fig. 8a and 8b show a diagram of the storage tanks in a system of interconnected heat storage modules. Fig. 8a shows a diagram of the storage tanks 12 in a system of modules 6 with a display of all the walls of the storage tanks 12. In order not to have to equip each space between the storage tanks 12 with a separate branch to the circulation pipe for the purposes of filling or draining the storage tanks 12. the spaces between the storage tanks 12 are created

-34CZ 38598 UI by connecting the storage tanks 12 connected to selected spaces inside the storage tanks 12. The area of the storage tanks 12, where the connection variants will be described, is marked with numbers 1 to 16. Fig. 8b shows a diagram of the storage tanks 12 with a display of three connection variants: - the storage tanks 12 marked with cross hatching and numbers: 1,5,8, 11, 14 and 15 have a fully circular shape;

- the storage tanks 12 have a circular shape with three convex arches and are marked with horizontal hatching and numbers: 4, 7, 10 and 13; and

- the storage tanks 12 have a shape with six convex arches, marked with vertical hatching and numbers: 2, 3, 6, 9, 12 and 16.

Due to the circular shape of the storage tanks 12, however, when individually draining or filling the storage tanks 12, e.g. due to their failure, it is necessary to follow such a procedure for shutting down or filling the adjacent storage tanks 12, so that all storage tanks 12 are loaded only by internal overpressure and so that the arched walls of the storage tanks 12 are not loaded by external overpressure. Before individually filling the storage tank 12 No. 8 with cross-hatching, it is not necessary to fill any adjacent storage tank 12. Before individually filling the storage tank 12 No. 4 with horizontal hatching, it is necessary to fill the storage tanks 12 No. 1, 5 and 8 with cross-hatching.

Before filling the storage tank 12 No. 9 with vertical hatching individually, it is necessary to fill the storage tanks 12 with cross hatching No. 1, 5, 8, 11, 14 and 15 and then the storage tanks 12 No. 4, 10 and 13 with horizontal hatching. Before draining the storage tank 12 individually, it is necessary to follow the inverse procedure. Before draining the storage tank 12 No. 9 with vertical hatching individually, it is not necessary to drain any adjacent storage tank 12. Before draining the storage tank 12 No. 4 with horizontal hatching individually, it is necessary to drain the storage tanks 12 No. 2, 3 and 9 with vertical hatching. Before draining the storage tank 12 No. 8 with cross hatching individually, it is necessary to drain the storage tanks 12 No. 2. 3, 6, 9, 12al6and then storage tanks 12 no. 4. 7 and 13 with horizontal hatching.

Fig. 9 shows a diagram of a floating heat storage tank with a single-level module system. The floating heat storage tank 5 primarily comprises a module system 6, in which there are modules 7 with the same height and the same immersion depth. In the floating heat storage tank 5, only the floats 10 are immersed in the base tank 1. The bases 11 and the storage tanks 12 are situated above the water level 13 in the base tank L. The floating heat storage tank 5, with its width, contains almost the entire width of the base tank 1 and has a uniform immersion depth, which corresponds to the used depth level of the base tank 1. The floating heat storage tank 5 also contains heating circulation units 16, withdrawal circulation units 17 and circulation pipes 14. Circulation units 16, 17 are built into energy modules 8 attached to modules 7 with storage tanks 12 around the perimeter of the system of modules 6. Thermal insulation and gas-tight casing are not shown here.

Fig. 10 shows a diagram of a floating heat storage tank with a three-level module system. The floating heat storage tank 5 contains three sets of modules 7, which have the same ratio of the height of the storage tanks 12 to the usable depth, so that each set of modules 7 has a different height of the storage tanks 12 and the floats 10. i.e. a different immersion depth. In the floating heat storage tank 5, only the floats 10 are immersed. The bases 11 and the storage tanks 12 are situated above the water level 13 in the base tank 1. The floating heat storage tank 5, with its width, contains almost the entire width of the base tank 1 and also uses almost the entire depth of the base tank 1, since the inner sets of modules 7 extend into larger depth levels of the base tank L. This floating heat storage tank 5 can therefore have a greater capacity for accumulated heat than the single-level floating heat storage tank 5 according to Fig. 9. The floating heat storage tank 5 also contains three sets of heating circulation units 16 and withdrawal circulation units 17 for the respective sets of modules 7 and circulation pipes 14. The circulation units 16, 17 are built into energy modules 8 attached to the modules 7 with storage tanks 12 around the perimeter of the module system 6. The thermal insulation and gas-tight casing are not shown here.

Fig. 11 shows a diagram of a stable heat storage tank with a three-level system of modules. The land on which the stable heat storage tank 5 is built has three levels of bearing capacity of the subsoil 3. Different

-35 CZ 38598 UI the bearing capacity of the subsoil 3 is shown by the different height of the foundations 9. The stable heat storage 5 contains three sets of modules 7, which have the same ratio of the height of the storage tanks 12 to the bearing capacity of the subsoil 3, so that each set of modules 7 has a different height of the storage tanks 12 according to the bearing capacity of the subsoil 3. The system of 6 modules fully utilizes the bearing capacity of the subsoil 3 on the entire plot. This stable heat storage 5 therefore has a greater capacity for accumulated heat than a single-level stable heat storage 5, which would be built according to the smallest bearing capacity of the subsoil 3 on the plot. The stable heat storage 5 also contains three sets of heating circulation units 16 and withdrawal circulation units 17 for the respective sets of modules 7 and circulation pipes 14. The circulation units 16, 17 are built into energy modules 8 attached to the modules 7 with storage tanks 12 around the perimeter of the module system 6. The thermal insulation and gas-tight casing are not shown here.

Fig. 12a, 12b and 12c show diagrams of a floating heat storage tank. Fig. 12a and 12b show a front view of a floating heat storage tank 5, Fig. 15c shows its plan view. The floating heat storage tank 5 floats on the water surface 13 in the base tank 1 and is formed by a system of 6 modules with a circular cross-section, which are interconnected by flat reinforcements into triangular shapes. The module 7 of the floating heat storage tank 5 has three basic parts: the storage tank 12, the base 11 and the float 10. The modules 7 are arranged inside the system of 6 modules. The energy modules 8 are arranged around the perimeter of the system of 6 modules. The width of the floating heat storage tank 5 is several times greater than its height, so that its stability against overturning is sufficiently ensured. The floating heat storage tank 5 is stabilized against horizontal movement in the base tank 1 by a guide frame 26, which has a floating part 27 and an anchoring part 28, which are hingedly connected to each other. The anchoring part 28 is also hingedly attached to the foundations on the bank 2 of the base tank 1. Fig. 12a shows the floating heat storage tank 5 with the storage tanks 12 filled with water to a height N and with the floats 10 fully submerged. Fig. 12b shows the floating heat storage tank 5 with empty storage tanks 12 and with the floats 10 partially submerged. When filling the storage tanks 12 with water from the base tank 1, the discharge head V must be overcome. The thermal insulation and the gas-tight jacket are not shown here.

Fig. 13 shows a diagram of a planar system of interconnected modules. In section A-A, a system of 6 modules interconnected in a stable heat storage tank is shown, which is built on a flat subgrade 3 with a uniform load-bearing capacity. Each module 7 in the system of 6 modules contains a storage tank 12 and a pedestal 11. In the pedestal 11 there is space for the circulation pipe and service platforms. For the stable heat storage tank, the supporting element is the foundation 9, which is built in the subgrade 3. Section B-B in the lower part of the figure is made in the area of the pedestals 11 and it shows the crossing of the modules 7, the spacing of which is smaller than their diameter. The storage tanks 12 and the circulation units can be arbitrarily connected via the circulation pipe in the system of 6 modules, since all modules 7 have the same height position and the height of the storage tanks 12 is the same for all modules 7. Thermal insulation and gas-tight jacket are not shown here.

Fig. 14 shows a diagram of a system of interconnected modules on a wavy subsoil. The diagram is essentially the same as in Fig. 13, differing only in the section A-A, from which it is evident that the system of 6 modules interconnected in a stable heat storage is built on foundations 9 formed in a wavy subsoil 3. All pedestals 11 and storage tanks 12 are of the same height, so that the upper surface of the system of 6 modules copies the slope of the subsoil 3. In this system of 6 modules, only groups of storage tanks 12 with the same height and with the same height position of the modules 7 can be connected to the circulation units via a circulation pipe, i.e. along contour lines, so that the circulation units have the same hydrostatic height. The thermal insulation and gas-tight jacket are not shown here.

Fig. 15 shows a diagram of a system of interconnected modules on a wavy subsoil and with the same height of the pedestals. The diagram is essentially the same as in Fig. 13, differing only in the section A-A, from which it is evident that the system of 6 modules interconnected in a stable heat storage is built on foundations 9 formed in the wavy subsoil 3. The upper surface of the system of 6 modules is horizontal, while the height level of the lower storage tanks 12 copies the slope of the subsoil 3. All pedestals 11 are of the same height. In this system of 6 modules, heat can be supplied by means of a circulation pump.

-36CZ 38598 UI piping with circulation units connected only groups of storage tanks 12 with the same height and with the same height position of the modules 7, i.e. along contour lines, so that the circulation units have the same hydrostatic height. Thermal insulation and gas-tight casing are not shown here.

Fig. 16 shows a diagram of a system of interconnected modules on a wavy subsoil and with the same height of the tanks. The diagram is essentially the same as in Fig. 13, differing only in the section A-A, from which it is evident that the system of 6 modules interconnected in a stable heat storage is built on foundations 9 formed in the wavy subsoil 3. The height of all storage tanks 12 is the same, while the upper surface of the system of 6 modules is horizontal and the height of the individual pedestals 11 is different, as the lower level of the pedestals 11 copies the slope of the subsoil 3. In this system of 6 modules, only groups of storage tanks 12 with the same height and with the same height position of the modules 7 can be connected to the circulation units via a circulation pipe, i.e. along contour lines, so that the circulation units have the same hydrostatic height. Thermal insulation and gas-tight casing are not shown here.

Fig. 17a and 17b show diagrams of two variants of a floating heat storage system with a system of modules with different diameters. The modules 7 have a pitch greater than the diameter and are interconnected by vertical stiffeners. The system of 6 modules contains three groups of modules 7 with different depth levels in the base tank L. In the upper part of Figs. 17a, 17b, vertical sections A-A through the systems of 6 modules are shown, the floor plans of which are in the lower part of the figures. Fig. 17a shows a diagram of the system of 6 modules, in which all modules 7 have the same diameter, but the heights of the storage tanks 12 are proportional to the immersion depth of the floats 10 in the base tank L Fig. 17b shows a diagram of a system of 6 modules with different diameters of storage tanks 12. In all modules 7 of this system of 6 modules, the floats 10 have the same diameter, since they use all the buoyancy that is available at a given depth level. The height of the storage tanks 12 and the pedestals 11 is the same in all modules 7 of all depth levels, but their horizontal diameter is different, while the ratio of the horizontal cross-section of the storage tanks 12 in the modules 7 of a certain depth level to the horizontal cross-section of the storage tanks 12 in the modules 7 of the greatest depth level is equal to the ratio of the draft of the floats 10 in the modules 7 of a certain depth level to the draft of the floats 10 in the modules 7 of the greatest depth level. Therefore, all the storage tanks 12 in the entire floating heat storage can be connected by a common circulation pipe. The circulation of water in all the storage tanks 12, regardless of their diameter, can be carried out using any circulation unit. Since the diameter of the floats 10 and the spacing between the modules 7 remain the same, the reinforcements between the storage tanks 12 or between the bases 11 of smaller diameter must have a greater width and thickness in order to bridge the distance between the modules 7 and to ensure the rigidity of the mutual connection of the modules 7. The thermal insulation and the gas-tight casing are not shown here.

Fig. 18a and 18b show diagrams of two variants of a floating heat storage tank with a system of modules with different diameters and with a gas-tight casing. The modules 7 have a pitch greater than the diameter and are interconnected by vertical stiffeners. The system of 6 modules contains three groups of modules 7 with different depth levels in the base tank 1. The surface of the part of the system of 6 modules, which contains the storage tanks 12 with bases 11. is provided with thermal insulation 31 and a gas-tight casing 32. In the upper part of Figures 18a, 18b, vertical sections A-A through the systems of 6 modules are shown, the plan views of which are in the lower part of the figures. Fig. 18a shows a diagram of the system of 6 modules, in which all the modules 7 have the same diameter, but the heights of the storage tanks 12 are proportional to the immersion depth of the floats 10 in the base tank L Fig. 18b shows a diagram of a system of 6 modules with different diameters of storage tanks 12. In all modules 7 of this system of 6 modules, the floats 10 have the same diameter, since they use all the buoyancy that is available at a given depth level. The height of the storage tanks 12 and the pedestals 11 is the same in all modules 7 of all depth levels, but their horizontal diameter is different, whereby the ratio of the horizontal cross-section of the storage tanks 12 in the modules 7 of a certain depth level to the horizontal cross-section of the storage tanks 12 in the modules 7 of the greatest depth level is equal to the ratio of the draft of the floats 10 in the modules 7 of a certain depth level to the draft of the floats 10 in the modules 7 of the greatest depth level. Therefore, all the storage tanks 12 in the entire floating heat storage can be connected by a common circulation pipe. The circulation of water in all the storage tanks 12, regardless of their diameter, can be carried out

-37 CZ 38598 UI using any circulating system. Since the diameter of the floats 10 and the spacing between the modules 7 remain the same, the reinforcements between the storage tanks 12 or between the bases 11 of smaller diameter must have a greater width and thickness in order to bridge the distance between the modules 7 and to ensure the rigidity of the mutual connection of the modules 7.

Fig. 19a and 19b show diagrams of two variants of a stable heat storage with a system of modules with different diameters and with a gas-tight casing. There are 7 modules in the system of 6 modules. The modules 7 are not firmly connected to each other. The spacing of the modules 7 is greater than their diameter. The system of 6 modules is provided with thermal insulation 31 and a gas-tight casing 32. The system of 6 modules is placed on foundations 9 with a gas-tight casing 32 so that each module 7 has a separate foundation 9 formed in the subsoil 3. The system of 6 modules is shown with storage tanks 12 filled with water. In the upper part of Fig. 19a, 19b, vertical sections A-A through the systems of 6 modules are shown, the floor plans of which are in the lower part of the figures. The system of 6 modules contains three groups of modules 7 with different bearing capacity of the subsoil 3. The different bearing capacity of the subsoil 3 is shown by different heights of the foundations 9. Fig. 19a shows a diagram of the system of 6 modules in which all modules 7 have the same diameter, but the heights of the storage tanks 12 are different, proportional to the bearing capacity of the subsoil 3. Fig. 19b shows a diagram of the system of 6 modules with different diameters of the storage tanks 12. In all modules 7 of this system of 6 modules, the foundations 9 have the same diameter, since they use all the bearing capacity of the subsoil 3 that is available in a given area of the land. The height of the storage tanks 12 and the pedestals 11 is the same in all modules 7 of all bearing capacities of the subsoil 3, but their horizontal diameter is different, proportional to the bearing capacity of the subsoil 3, while the mutual ratio of the horizontal cross-sections of the storage tanks 12 in the modules 7 is equal to the mutual ratio of the bearing capacities of the subsoil 3 in these modules 7, i.e. the mutual ratio of the heights of the storage tanks 12 in these modules 7. The system of 6 modules contains in all modules 7 of all bearing capacities of the subsoil 3 storage tanks 12 with a uniform height and pedestals 11 also with a uniform height. Therefore, all storage tanks 12 in the entire stable heat storage can be connected by a common circulation pipe. Water circulation with proportional filling of all storage tanks 12 regardless of their diameter can be carried out using any circulation unit.

Fig. 20 shows a diagram of a system of interconnected modules with parallel connection of the circulation pipeline. The upper part of the figure shows a vertical section A-A through a system of 6 modules, the lower part of the figure shows a horizontal section B-B through a system of 6 modules. The spacing of the modules 7 is smaller than their diameter. In all modules 7 of this system of 6 modules, the bases 11 have the same diameter. The height of the storage tanks 12 is the same in all modules 7 of all bearing capacities of the subsoil 3, but their diameter is different. The storage tanks 12 are connected in parallel by separate branches to a horizontal circulation pipe 14 located below the storage tanks 12. The storage tanks 12 are grouped into three groups by the circulation pipe 14, each group of storage tanks 12 is connected to a circulation unit 16. The groups of storage tanks 12 are interconnected by a closable circulation pipe 14 in the event of a failure of one of the circulation units 16 or to improve the possibilities of regulating the water circulation in the storage tanks 12. The storage tanks 12 are connected here to the circulation unit 16 in parallel, so that they can be filled and drained simultaneously. Each branch of the circulation pipe 14 is equipped with a closure 15, which allows the flow of water in the storage tank 12 to be regulated. The thermal insulation and the gas-tight casing are not shown here.

Fig. 21 shows a diagram of a system of interconnected modules with independent connection of the circulation pipe. The upper part of the figure shows a vertical section A-A of a system of 6 modules, the lower part of the figure shows a horizontal section B-B of a system of 6 modules. The spacing of the modules 7 is smaller than their diameter. In all modules 7 of this system of 6 modules, the bases 11 have the same diameter. The height of the storage tanks 12 is the same in all modules of all bearing capacities of the subsoil 3, but their diameter is different. Each storage tank 12 is connected by a separate circulation pipe 14 leading up to the circulation unit 16. All storage tanks 12 are connected to the circulation unit 16 completely independently. Each separate circulation pipe 16 is equipped with a valve 15, which allows the flow of water in the storage tank 12 to be regulated and which is located next to the circulation unit 16, therefore it is easily accessible for operation and maintenance. This arrangement is

-38CZ 38598 UI advantageous for increasing the reliability of the closures 15. because the water and all internal spaces of the 6-module system will be heated to an elevated temperature by heat storage. Thermal insulation and gas-tight jacket are not shown here.

Fig. 22 shows a diagram of a modular heat storage unit with a heat supply device and a heat extraction device. The heat supply device includes a heating circulation unit 16. which is connected via a circulation pipe 14 to the heat storage unit 5 and to a heating exchanger 19. which is powered from an external source. The heat extraction device includes a extraction circulation unit 17. which is connected via a circulation pipe 14 to the heat storage unit 5 and to the heated object 25, in which heat is extracted using an object exchanger 21. The circuits of both devices are interconnected. The circulation pipe 14 is common for both heat supply and heat removal and is connected to the lower ends of the storage tanks 12. The warmer water remains in the upper part of the storage tanks 12. Therefore, this embodiment is more suitable for smaller heights of the storage tanks 12. in which the water is better mixed throughout the entire height of the storage tank 12. No circulation pipe is located inside the storage tanks 12, maintenance is simpler. The ventilation pipe 24 is closed, a compressor 22 and a gas tank 23 are available to regulate the gas pressure above the water level in the storage tanks 12. The thermal insulation and gas-tight casing are not shown here.

Fig. 23 shows a diagram of a modular heat storage unit with a heat supply device and a heat withdrawal device. The circuits of both devices are interconnected. The branches of the circulation pipe 14 for heat supply and the circulation pipe 14 for heat removal, in which colder water is located, are connected to the lower days of the storage tanks 12 and the branches of the circulation pipe 14 for heat supply and the circulation pipe 14 for heat removal, in which warmer water is located, are connected to the upper days of the storage tanks 12. The warmer water is retained in the upper part of the storage tanks 12. Therefore, this embodiment is more suitable for larger heights of the storage tanks 12. in which the water does not mix throughout the entire height of the storage tank 12. Only a part of the circulation pipe 14 is located inside the storage tanks 12. Maintenance is almost as simple as in the embodiment according to Fig. 22. Thermal insulation and gas-tight casing are not shown here.

Fig. 24 shows a diagram of a modular heat storage tank with a heat supply device and a heat withdrawal device. The circuits of both devices are interconnected. The branches of the circulation pipe 14 for heat supply and the circulation pipe 14 for heat removal, in which colder water is located, are connected to the lower days of the storage tanks 12. The branches of the circulation pipe 14 for heat supply and the circulation pipe 14 for heat removal, in which warmer water is located, are also connected to the lower days of the storage tanks 12. but they continue inside the storage tanks 12 and end in the upper part of the storage tanks 12. The warmer water remains in the upper part of the storage tanks 12. Therefore, this embodiment is more suitable for larger heights of the storage tanks 12. in which the water does not mix throughout the entire height of the storage tank 12. The circulation pipe 14 is located inside the storage tanks 12. Maintenance is more demanding than in the embodiment according to Fig. 22 or according to Fig. 23. Thermal insulation and gas-tight casing are not shown here.

Fig. 25 shows a diagram of a modular heat storage tank with a heat supply device and a heat withdrawal device. The circuits of both devices are partially separated. The branches of the circulation pipe 14a for heat supply and the circulation pipe 14b for heat removal, in which colder water is located, are connected to the lower days of the storage tanks 12. The branches of the circulation pipe 14a for heat supply and the circulation pipe 14b for heat removal, in which warmer water is located, are also connected to the lower days of the storage tanks 12. but continue inside the storage tanks 12 and end in the upper part of the storage tanks 12. The warmer water remains in the upper part of the storage tanks 12. Therefore, this embodiment is more suitable for larger heights of the storage tanks 12. in which the water does not mix throughout the entire height of the storage tank 12. The circulation pipe 14a is located inside the storage tanks 12. 14b. Maintenance is therefore more demanding than in the design according to Fig. 22 or Fig. 23. Thermal insulation and gas-tight casing are not shown here.

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Fig. 26 shows a diagram of a modular heat storage tank with a heat supply device and a heat withdrawal device. The circuits of both devices are partially separated. In addition, in contrast to the embodiment according to Fig. 22, the circuit of the device (14b, 17. 20) for heat withdrawal is fully separated from the circuit of the heated object 25 by the withdrawal exchanger 20. The circuit of the heated object 25 includes the object circulation pipe 14c. object circulation unit 18 and object exchanger 21. This arrangement is suitable if a modified liquid circulates in the modular heat storage tank 5, which increases the resistance of the storage tanks 12. circulation pipe 14a. 14b. circulation units 16. 17 and exchangers (19. 20) against corrosion and it is necessary to secure it against losses in the event of malfunctions of the heating system in the heated object 25 and in the long-distance pipeline. Thermal insulation and gas-tight jacket are not shown here.

Fig. 27 shows a diagram of a modular heat storage without pedestals, with thermal insulation and a gas-tight casing. The upper part of the figure shows a section A-A of the lower part of the figure, the lower part of the figure shows a section B-B of the upper part of the figure. In a system of 6 modules, each module 7 contains a storage tank 12. All modules 7 have the same diameter, the same height and their spacing is greater than their diameter. The modules 7 are not rigidly connected to each other. A separate circulation pipe 14 is connected to each storage tank 12. Each separate circulation pipe 14 can be equipped with its own valve to regulate the flow of water flowing through it, which is not shown here. The system of 6 modules is provided with thermal insulation 31 and a gas-tight casing 32. The system of 6 modules is placed on foundations 9 with a gas-tight casing 32 so that each module 7 has a separate foundation 9 formed in the subsoil 3. The system of 6 modules is shown with storage tanks 12 filled with water.

Fig. 28 shows a diagram of a modular heat storage tank with a base, thermal insulation and a gas-tight casing. The upper part of the figure shows a section A-A of the lower part of the figure, the lower part of the figure shows a section B-B of the upper part of the figure. In a system of 6 modules, each module 7 contains a base 11 and a storage tank 12. All modules 7 have the same diameter, the same height and their spacing is greater than their diameter. The modules 7 are not rigidly connected to each other. A separate circulation pipe 14 is connected to each storage tank 12. Each separate circulation pipe 14 can be equipped with its own valve to regulate the flow of water flowing through it, which is not shown here. Above the upper network of the circulation pipe 14 there is a space with a height necessary to place a working platform for operation and maintenance. The system of 6 modules is provided with thermal insulation 31 and a gas-tight casing 32. The system of 6 modules is placed on foundations 9 with a gas-tight casing 32 so that each module 7 has a separate foundation 9 formed in the subsoil 3. The system of 6 modules is shown with storage tanks 12 filled with water.

Industrial applicability

The heat storage tank has the prerequisites for extensive use:

- the system of modules with storage tanks has a simple, relatively light, yet strong and flexible construction, which is the basis for its reliability, low price and long service life;

- modular design further reduces production costs;

- the relatively small surface area of the module system reduces the specific costs of thermal insulation;

- the surface of the storage tanks is easily accessible for corrosion protection;

- individual parts of the module system are easily accessible for operation and maintenance;

- optimally uses the space of the land on which it is located;

- they can be made stable on a solid base or floating in a base tank;

- it can use water, which has a high specific heat and is commonly available, to store heat;

- allows short-term and long-term heat storage;

- the heat storage cycle has very good energy efficiency;

- the upper platform and side walls of the module system can be used to accommodate a solar and/or wind power plant;

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- water in the base tank heated by waste heat from the floating device can be used for recreational or production purposes;

- simple concept allows for automation of operation.

The technical solution will enable:

- significantly reduce heat storage costs;

- significantly expand seasonal heat storage;

- effectively use ecological energy sources with constant or variable production for heat storage;

- increase the efficiency of promising technologies for large outputs and long-term electricity storage capacities (CB, LAES, CAES).

Claims (2)

PROTECTION CLAIMS 1. A heat storage device (5) comprising a system (6) of modules, wherein in the system (6) of modules each module (7) comprises a storage tank (12) filled with a heat transfer fluid, wherein at least two modules (7) have the same or different diameter, the same or different height, and their spacing is greater than or smaller than their diameter or equal to their diameter, wherein a separate circulation pipe (14) is supplied to each storage tank (12) or a common circulation pipe (14) is supplied to at least two storage tanks (12), and wherein the system (6) of modules is provided with thermal insulation (31), characterized in that the system (6) of modules is provided with a gas-tight casing (32), wherein this system (6) of modules is placed on foundations (9) with a gas-tight casing (32) such that at least one module (7) is built on a separate foundation (9) formed in the subsoil (3); or the entire system (6) of modules is built on a common foundation (9) formed in the subsoil (3), wherein the gas-tight shell (32) is made of corrugated, edged or thin-walled sheet metal, or of thin-walled laminated material, or of non-metallic materials, or is formed by a gas-tight coating on the peripheral structure or on the peripheral thermal insulation (31) of the system (6) of modules. 2. Heat storage tank (5) according to claim 1, characterized in that the module (7) comprises a base (11) for supporting at least one storage tank (12).