DE3312329A1 - Ground heat store - Google Patents

Abstract

The purpose of year round, economic heating of buildings by means of heat sources which supply thermal energy only at times and with sizeable interruptions, e.g. solar collectors, is served by a ground heat store in which both the storage medium and the thermal insulation consist of ground covered with vegetation. In order to avoid excessive thicknesses of insulating layers, the storage medium and the insulation are dried out, and renewed soaking by precipitation is prevented by covering with a water-tight layer. The introduction of the heat exchanger elements into the storage medium is performed with the aid of bores using an earth-displacing hammer, followed by laying outgoing and returning pipes for a heat transfer medium, in particular water. In order to improve the energy budget, the core of the store is surrounded by one or more shells at a relatively low temperature, which are also used at times for heating. A particularly centrally arranged buffer store having temperature stratification in an installation shaft permits a particularly simple arrangement of all assemblies. In the case of new buildings, the ground heat store can be arranged below the house and the solar collector on the roof of the house. In the case of old buildings, the ground heat store can be constructed next to the building together with a solar collector on top.

Description

DESCRIPTION

Heat underground storage

The invention relates to a heat underground storage, the Storage medium consists of natural soil and predominantly has a temperature that is significantly above the temperature of the surrounding soil, for Use in such building heating systems and domestic water heating systems, where the heat source is only temporarily is effective with longer interruptions (up to several months), especially with solar collectors. Grown soil is understood to mean soil that was not moved during the construction of the heat storage tank.

The thermal underground storage is to provide the thermal energy at a temperature level that is used for direct Heating buildings without the interposition of a heat pump is sufficient all year round. He should be excess absorb generated thermal energy and release it again during the interruptions in energy generation can, whereby these two processes must be feasible with the required performance.

It is known that one for heat underground storage, their temperature level is permanently or at least predominantly above that of the surrounding soil, as a storage medium use natural soil "(German patent application 29 10 77 * 0 ·

It is also known to have the necessary heat exchanger elements generate in the storage area by driving jacket pipes into the ground can be inserted into the pipes by a heat transfer medium be flowed through, by means of a

Filling compound, the heat exchange between the jacket tube and door the internal pipes is taken care of (German patent application 30 16 456).

In addition, it is theoretically evident that a subdivision of the heat storage underground in shells, the temperatures of Remove shell to shell towards the outside, both reducing the heat loss of the heat storage system to the outside, as well as to reduce the temperature drop that occurs during charging and discharging of the heat storage tank allowed (reduction of irreversible, i.e. entropy-increasing heat transports).

O The developments and inventions to date have

§ has not yet led to a temporary effect-

_w the heat sources, such as solar collectors, a storage

X 15 cherkonzept can be placed side by side, withstands economic ^-scientific requirements. That goes for everyone

^m previously proposed heat storage, which is used

is intended for building heating systems where the heat source only works temporarily with longer interruptions (up to 2 © for several months), regardless of the storage medium is used: water, filling base, latent heat transfer medium or other, but also for heat storage with the cheapest storage medium, namely with natural soil.

The invention is based on the object of the low temperature requirement of buildings solely through solar energy (or through other, only intermittent heat sources) economically worthwhile to satisfy. The problem lies essentially in finding a heat storage device with the following properties:

- Storage tank temperature year-round at least k ^ ° C (The comparatively high temperature level makes the use of a heat pump unnecessary, which contrary to the task

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position would require external energy).

- Storage capacity (available amount of heat above k5 C) about 2/3 of the annual energy requirement

- Annual energy loss is significantly smaller than the storage capacity

- Storage medium is grown soil (for economic reasons)

- essentially one loading and unloading process per year

- the maximum charging power corresponds to the maximum

Output of the solar collector (or another heat source)

- the maximum discharge power corresponds to the maximum required heating power (including additional Consumer)

This object is achieved according to the invention in that the heat-underground storage is created in such a way that the surrounding grown soil dries out and acts as thermal insulation the heat storage tank is used.

The advantage that can be achieved with the invention is that, for the first time, a heat accumulator is produced in such a cost-effective manner It can be that the economically sensible heating of buildings exclusively by solar energy is made possible. Grown soil is the cheapest possible thermal insulation, because only in this case significant earth movements during the construction of the heat storage tank can be avoided.

In this geothermal heat storage system, the thermal energy stored for the first time is used in the storage area and then also the natural soil moisture in the heat-insulating soil layer in to drive away the wider area. Evaporation and condensation processes of the water in the earth

Soil plays an essential role, the temperature will increase only increase noticeably when the moisture in the respective area has been almost completely expelled «That Driving away the moisture causes a decrease in thermal conductivity of the grown soil by a factor e.g. 3 Thermal insulation required thickness of the earth layer of e.g. 15 meters by the mentioned factor 3 to e.g. 5 meters, The figures mentioned for example are strong depending on the type of soil. It is necessary to have a sufficient distance to the water table to include,

Appropriate refinements and developments of the invention Heat geothermal storage results from the 15 claims 2 to 5.

Q According to a further embodiment of the invention (claim 6)

O heat exchanger elements are installed in the storage area

{= brought, which are produced as follows: generate

N of elongated cavities of approximately circular

Cross-section with an earth displacement hammer, inserting Pipes for the heat transfer medium flowing back and forth, filling the cavities with material that conducts heat well.

This embodiment of the invention ensures that a compacted zone is created in the vicinity of the feed hole which conducts the heat considerably better than the natural soil. That is why the displacement well is superior to conventional boreholes with excavated earth. In contrast to the German patent application War. 30 16 456 is not rammed with casing pipes because they are costly and impractical at greater depths.

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According to a further embodiment of the invention (claim 7) the heat exchanger elements can have an angled or curved shape. An angled shape can be created by multiple Attachment of the displacement hammer can be achieved. A curved shape can be achieved after a slight change in conventional displacement hammers.

This further embodiment of the invention divides the heat-geothermal storage volume into different Partial areas enabled, whereby the temperature of the external sub-areas is lower than the temperature of the Sub-areas further inside (see the example shown in the drawing).

According to a further embodiment of the invention (claim 9), the heat exchanger elements belong to different groups on, with the properties mentioned in the claim.

This further embodiment of the invention ensures that the thermal energy loss of the memory is substantial is reduced so that heating energy can be taken from the partial area at the time has a temperature just sufficient for this and that thermal energy is fed into the sub-area whose temperature is just below the temperature of the thermal energy generated (e.g. in the solar collector) lies. These measures represent a particularly economical way of handling the available energy.

According to a further embodiment of the invention (claim 10), a buffer memory is assigned to the memory as a whole with further characterizing features mentioned in the claim.

^ ₀ Through this further development of the invention it is achieved that an intermittently occurring energy supply

(ζ.B * from the solar collector when the sky is clear and high Position of the sun) as well as an intermittent energy demand ('e.g. domestic water heating) initially collected by the buffer storage tank and balanced over time to the heat storage tank is passed on, whereby an average smaller temperature drop on the heat exchanger θlementen occurs. In addition, it is achieved that an energy supply occurring in winter directly via the buffer storage can be used as short-term storage without switching on the ¥ poor earth storage.

From the claims 11 to 18 result further functional _ moderate refinements and developments of the invention Heat geothermal storage.

According to a further embodiment of the invention (claim J5 15 19) is / are the buffer tank (s) or an additional - rather equalizing tank able to store the heat transfer medium

take up dium from the solar collector as long as this cannot perform due to insufficient irradiation and should therefore be emptied.

This further embodiment of the invention ensures that the solar collector without antifreeze and can be operated without a heat exchanger in the buffer tank can and that the night-time cooling of the heat transfer medium in the solar collector is avoided.

Appropriate refinements and developments of the invention Ground heat storage system result from claims 20 to 22.

An embodiment of the invention is shown in the drawing and is described in more detail below. The drawing shows an underground heat storage system in

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connection with a solar collector K on the roof and with underfloor heating F for a new single-family house, which works exclusively with solar energy and without any other alternative equipment such as a heat pump, is heated.

The heat exchanger elements belong to two groups: the enforce radially arranged heat exchanger elements the inner part I of the heat storage tank with the higher temperature, while the enveloping, kinked Heat exchanger elements pass through the outer sub-area A. The displacement wells will be made from the excavation, which is then to accommodate the installation shaft. For the heat exchanger elements the earth displacement hammer is in the outer section a second time from a ring trench to be filled in later. All tubes of the heat exchanger elements are led individually into the installation shaft, which means that a repair attempt or shutdown in the event of leaks in individual pipes. They all flow into one of four manifolds are led around horizontally in a ring inside the installation shaft. The buffer memory P works with Temperature stratification, which is stabilized by built-in perforated sheets. Boiler feed water is used as filling.

Four circulation pumps take care of the exchange of the water in the buffer tank

- With the heat exchanger elements of the inner sub-area of the heat storage tank

- With the heat exchanger elements of the outer sub-areas of the heat-Erdspelchers

- with the roof collector and
with the underfloor heating

A microcomputer receives temperature readings from the various compartments of the buffer tank, from the T5 partial areas of the heat storage tank from the return of the Underfloor heating, from the return of the solar collector, from

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a radiation absorber, from the outside air and room air and thus controls the four circulation pumps and the valves, which connect the circuits with the most favorable sections of the buffer tank. When the temperature on the return of the solar collector is lower than the temperature of the heat storage in the outer area, the The water cycle through the solar collector is shut down and emptied with a fifth pump. The waterproof cover W allows the storage tank to dry out. rich and especially the 5 m thick thermal insulation layer from the ground around the heat storage tank.

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Claims (1)

Applicant Dr. Georg Schultze, Solartechnik Erikaweg 5, 2111 Handeloh Description? Heat underground storage PATENT CLAIMS Π »1 underground heat storage, the storage medium of which consists of natural soil and predominantly has a temperature which is significantly above the temperature of the surrounding soil, for Use in such building heating systems and domestic water heating systems where the heat source is only at times with longer interruptions (up to several Months) is effective, especially with solar ) collectors, characterized } that the heat storage is created in such a way that the ^s 15 surrounding natural soil dries up \ and serves as thermal insulation for the heat storage tank. 2. Heat underground storage according to claim 1, characterized in that the drying out in the area of thermal insulation by means of supplied heat in connection with a waterproof cover of the entire storage area including an additional edge zone is reached. 3 »WäOTie-Erdspeicher according to claim 2, characterized characterized in that the cover by structures that serve other purposes or by a The only layer introduced for this purpose is carried out at any convenient depth below the surface of the earth can be arranged, e.g. to enable plants to grow above it. •••••• ι · - .. " 4. heat earth reservoir according to claim 3, characterized characterized in that the waterproof cover is provided with a drainage and water drainage system is drained so that the collected water is sufficient is continued far from the memory area. 5. heat underground storage according to claim 1, characterized characterized in that the thermal insulation is partially carried out by other insulating materials. 6. heat geothermal storage according to claim 1, characterized characterized in that the storage area is interspersed with heat exchanger elements ^ the following are produced: creating elongated cavities with an approximately circular cross-section with an earth displacement hammer, inserting pipes for the heat transfer medium flowing in and out, fill the cavities with material that conducts heat well. 7. heat-underground storage according to claim 6, characterized in that the tubes for the Heat transfer medium Y-shaped at the lower end ' with the downward-facing and closed branch serving as a dirt trap. 8. heat underground storage according to claim 6, characterized in that the heat exchanger elements partially have an angled and / or curved shape. 9. heat underground storage according to claim 6, characterized in that the heat exchanger elements belong to different groups, whereby - each group belongs to a certain sub-area of the Heat storage unit belongs to, - the sub-areas generally differ in terms of temperature. - the sub-areas with low temperature continue to expand located outside, - the heat exchanger elements of each group are connected in parallel with regard to the flow, - di © flow through each group can be generated individually by a circulation pump, 10. heat-geothermal storage according to claim 6, characterized in that the heat-Erdspei » rather as a whole, a buffer memory is allocated to the o Contains a heat transfer medium that it communicates with the heat exchanger elements of the heat storage tank, with the energy generator, e.g. solar collector, and the energy consumer, ζ, B. Building heating, can replace. 11. heat geothermal storage according to claim 6, characterized Section 15 indicates that each group has a ^ a separate buffer memory is assigned to the preferred wise in the associated sub-area of the heat storage tank Co lies and has thermal contact with this sub-area and EVERY which contains a heat transfer medium, which it communicates with the heat ^ j 2o exchange elements of the associated sub-area of the Heat earth storage, with the energy generator, e.g. solar collector, and the energy consumer, i.a. Building heating, can replace. 12, "heat-ground storage of claim 1o or 11, characterized GEK & ■ η η is characterized in that not the heat transfer medium itself, but by interposing of heat exchangers is only exchanged the heat energy whereby different in the various circuits pressures and / or different chemical compositions of the heat transfer medium, e.g. antifreeze additive, are made possible. 13. heat-geothermal storage according to claim 10 or 11, characterized in that a buffer memory a preferably standing container is in the OO several horizontal perforated sheets are built in, which stabilize an existing temperature stratification and that the container has a plurality of pipe sockets at different heights, preferably one between each two perforated plates as well as above the top and bottom perforated plate, for the inflow and outflow of the heat transfer medium, in order to be able to create and maintain a temperature stratification in the buffer storage, ■ fif, ¥ ärme-Erdspeicher according to claim 13 »thereby characterized in that the buffer storage is set up in a preferably cylindrical shaft, enables all-round external access to the container and entry into the container. 15. Värme-Erdspeicher according to claim 14, characterized characterized in that the shaft serves as the starting point for the heat exchanger elements. 16. Värme-Erdspeicher according to claim "\ h, characterized in that the shaft contains all installations such as pumps and valves and in particular the manifolds for the individual groups of heat exchanger elements in the form of ring lines. 17 · Heat underground storage according to claim 10, characterized in that the domestic water heating takes place in a heat exchanger tube that mainly rises the buffer tank in the direction of flow and is provided with its own pipe penetrations through the buffer tank wall. 18. Heat underground storage according to claim 11, characterized in that the domestic water heating takes place in a heat exchanger tube, which in the flow direction the buffer tank in increasing order Temperature and each buffer tank essentially 33Ί2329 - 5 chen runs through increasing. 19 »Heat underground storage according to claim 10 or 11, characterized characterized in that either the buffer tank (s) or an additional expansion tank are able to remove the heat transfer medium from the solar collector record; as long as this because of a lack of radiation cannot perform and should therefore be emptied. 20 _β heat underground storage according to one of claims 1 to 19 »characterized in that it is arranged below a solar collector forming the heat source, the solar collector partially performing the function ι the waterproof cover according to claim 1 takes over and jj being the rear thermal insulation of the solar collector ] 15 at the same time represents a thermal insulation of the heat storage tank according to Z above. 21. Heat underground storage according to one of claims 1 to 19, characterized in that it is below of a building (new construction) is arranged, the foundation of the building due to expected temperature fluctuations the earth must be designed reinforced. 22. Heat underground storage according to one of claims 1 to 21, characterized in that the (partially) Heating of buildings, built-in swimming pools or outdoor swimming pools through direct thermal contact with the Heat underground storage happens.