DE102011000655A1 - Heat transporting method, involves changing volume of chambers, so that total capacity of chambers is constant, and connecting chambers with connection pieces, such that filling and draining of chambers takes place temporarily at same time - Google Patents

Abstract

The method involves transporting a heat storage medium in a transportable container (101) from a heat source to a heat sink, where the container has connection pieces for loading and discharging the medium. The container is used with chambers for receiving hot and cooled water. Volume of the chambers is changed in such a manner that the total capacity of the chambers is constant. The chambers stay in fluid communication with the connection pieces, such that the filling and draining of the chambers takes place temporarily at the same time. An independent claim is also included for a transportable container for transporting heat from a heat source to a heat sink.

Description

The invention relates to a heat transport system. In particular, the invention relates to a heat transport system, which without predetermined, installed transport routes, z. B. lines and the required mobile heat storage and the process for loading and unloading.

Rising energy prices as well as the anthropogenic greenhouse effect caused by the burning of fossil energy sources mean that existing energy needs to be used more efficiently and energy sources that have not yet been exploited. With the help of the mobile heat storage described here, it is possible to transport previously unused waste heat from the source (heat source) to heat consumers (heat sinks) to use them there. As a result, other energy sources can be substituted in the heat sinks and thus the environment can be relieved.

In principle, it is possible to transport this waste heat from the source via a wired local or district heating network to heat sinks. In many cases, however, the construction of such a wired heat network is difficult or uneconomical. This is especially the case if there are difficult terrain situations such. B. the crossing of rivers or railways to overcome.

There are generally three physical processes available for storing thermal energy without conduction: sensitive, latent and thermochemical heat storage. The first systems that use latent heat storage to transport them without line binding are already available on the market. In the case of these latent heat accumulators based on sodium acetate, the temperature which can be released is limited to approximately 50 ° C. due to the process.

The object of the invention is to make available existing waste heat potentials in a simplified and favorable manner and thus to contribute to resource conservation and climate protection.

This object is achieved by methods according to claims 1 and 6 and by the heat transfer systems according to claims 5 and 9.

The invention is based exclusively on the sensitive heat storage. The temperature of the heat carrier (the heat storage medium) is thus changed to absorb or release heat energy. The charged heat carriers are then transferred from the location of a heat source to a heat sink where the heat is discharged.

The invention is particularly intended for the mobile use of waste heat from industrial, commercial and agricultural sources. The use of waste heat, as obtained in many industrial processes, but also in power plants and biogas plants, can be stored and transported according to the invention. This waste heat is currently only partially used and usually passed through cooler into the atmosphere, as often no direct heat demand in the necessary magnitude at the place of origin is present.

An essential aspect of the invention is, in contrast to known methods of heat storage and the transport of stored heat, to propose methods and devices which are particularly simple in construction and particularly advantageous in use.

In general, waste heat can be generated as low-temperature heat (below 100 ° C, eg cooling water from cogeneration plants of biogas plants) as well as high-temperature heat (above 100 ° C, eg process steam or waste gas from combined heat and power plants). Therefore, two concepts are proposed, one of which allows the storage of low-temperature heat (T <100 ° C) and another allows the storage of high-temperature heat (T> 100 ° C).

According to the invention, low-temperature heat is stored in a heat storage fluid and high-temperature heat in a solid heat storage medium. As a heat storage fluid, water is used because of its high specific heat capacity and easy handling. Optionally, this water additives to reduce corrosion, frost resistance, etc. are added.

In both cases, low-cost storage media are used, which are also available almost everywhere.

According to the invention, containers with the storage medium are transported on the available transport paths between heat sources and heat sinks. The concepts are particularly geared to road transport, but other transport systems are conceivable. Storage media with a mass of 5 to 50 tons are used. For easier integration into existing logistics concepts, the storage tanks can be designed in container-like design.

The transfer of low-temperature heat is carried out according to the invention to heat source and heat sink by rapid pumping of the Heat storage fluids from the mobile storage in the stationary storage. In the method according to the invention, the discharged storage medium is taken from the stationary storage in the same container, which supplies the loaded storage medium. It is crucial that a mixing of hot and cold heat storage fluid is prevented. This is realized by several chambers in the container, which are each variable in size. The total volume of the chambers, however, remains constant. A chamber can thus be increased / decreased at the expense of another chamber by the chamber separation is moved.

According to the invention, the insulating piston or tube separations described below can be used for this purpose. To increase the reliability during refilling can leak-free quick-closing valves, as z. B. for the handling of chemicals application can be used. Even if the disconnection of the coupling occurs accidentally during the transfer process under pressure, the leak rate is only a few milliliters (example: www.waltherpraezision.de, series CN).

The diameter of the connecting piece of the low-temperature accumulator is to be dimensioned sufficiently due to the high Umpumpraten the heat storage fluid. At a pumping rate of, for example, 5 m ³ / min, the connecting pieces should be designed in DN 150 or DN 200. The diameter of the connecting pieces is usually the same as that of the connecting pipes or hoses. When choosing too small diameter, the pressure loss increases disproportionately high. The choice of large diameter is uncritical from a purely technical point of view, but it leads to high costs z. B. for the shut-off valves.

The amount of low temperature heat that can be transported by a truckload is highly dependent on the temperature level. At the top, the temperature is limited to 95 ° C for safety reasons. Thus, above all, the minimum temperature required for the heat sink determines the energy storage density per truck load. If this, for example in swimming pools, is 40 ° C, a temperature difference of 55 Kelvin can be used, and in a storage mass of 23 tonnes, about 1,500 kWh can be transported.

The high-temperature storage according to the invention is of particular interest for the utilization of the waste gas waste heat from generators for power generation or combined heat and power plants. There are currently about 5,000 biogas plants with a total electrical output of around 1.7 GW installed in the Federal Republic of Germany, which are operated with an average availability of 8,000 hours per year. The usable by biogas plants thermal power corresponds approximately to their electrical power output. The proportion of usable high-temperature heat is just under half of the thermal power. The vast majority of biogas plants do not have sufficient heat utilization, which is mainly due to the sites in rural areas.

The high-temperature heat accumulator according to the invention is a variation of the operating principle of the kiln heater of the blast furnace process (so-called Cowper), in which fireclay-based bricks are used as heat storage material and in which the heat transfer also takes place by direct gas-solid contact without additional heat exchanger. For mobile heat storage, however, the use of fireclay bricks is eliminated because they have too low a mechanical strength. In addition, their high thermal capacity is not required in the storage of engine exhaust. It is inventively a solid, porous, preferably mineral storage material used. According to a preferred embodiment, a gravel filling represents a suitable combination of mechanical and thermal stability with simultaneously low material costs.

With a storage density of about 100 kWh per ton of storage mass, the economically induced transport radius for high-temperature heat is greater than that for low-temperature heat. In addition, the storage of high-temperature heat opens up further fields of application, which scarcely occur with the storage according to the invention of low-temperature heat or first commercially available mobile latent heat storage units based on sodium acetate (see www.latherm.de) in which the decoupled temperature is limited to about 50 ° C. let realize. These other fields of application include, for. As the steam generation, the operation of Adsorptionskälteanlagen for low temperature applications as well as for drinking water hygiene reasons required to kill legionella hot water heating to about 60 ° C. Even if a part of this field of application could theoretically be opened up by the use of other latent heat storage media, this would be done at the expense of higher costs for controlling corrosion problems and a possible classification in the dangerous goods regulation. For the method of thermochemical mobile heat storage, z. As with zeolites, were able to establish today no method on the market.

The loading and unloading with high-temperature heat is done by direct gas-solid contact, as this the best heat transfer can be achieved. In addition, omitted here Due to the process, the costs for heat exchangers. The envelope of the heat storage material is carried out according to the invention by exchanging transport units, which may be designed, for example, as a container.

Short transport and turnaround times are of particular economic importance for the realization of the invention. Depending on the technology used, the agreed prices for the waste heat and the transported storage mass, the value of a storage load ranges from 50 to over 100 euros. With a future increase of the permissible total weight for truck transports this value would increase accordingly.

At the current operating costs for trucks or larger tractors of about 60 to 80 euros per hour (including drivers) is the economically acceptable transport radius in the range between 5 and 15 kilometers and is thus significantly larger than the supply radius of most local heating networks.

The advantage of the mobile high-temperature heat storage according to the invention consists in the extremely simple and robust construction. The heat accumulator can, if it is loaded with the exhaust gases of internal combustion engines whose temperature is usually 400-500 ° C, charged, neither overheat nor can it be overloaded. In this temperature range z. B. gravel can be used as a heat storage material, since a thermal transformation of the material, the so-called quartz crack, would take place only at 573 ° C and can be safely excluded. With the reference price of gravel, which is implemented in gravel factories on the order of several thousand tons per day and is in the range of about 10 euros per tonne, no other known heat storage material can compete. In addition, gravel is commercially available in many particle size distributions, can be easily res screened and has compared to many other rocks a relatively round structure, which has a positive effect on the flow of gas and a loosening process necessary gravel bedding.

To increase the heat transfer from the hot exhaust gas to the colder gravel, the highest possible turbulence of the gas flow is required, which leads to an increased gas-side differential pressure or pressure loss over the gravel bed. This pressure loss is limited on the engine side upwards by the rising exhaust gas temperatures. Different engine types allow different maximum exhaust back pressures. As a general upper limit, however, 10 mbar maximum exhaust gas back pressure can be considered. Thus, the high-temperature accumulator is to be dimensioned so that a maximum back pressure of about 7 mbar can not be exceeded.

The calculation of the pressure drop in the flow of bedding can be calculated according to Ergun's equation, which includes the empty tube flow velocity of the gas, its temperature, density and viscosity, and the ball diameter of the bed and its void ratio.

With increasing temperature, with constant gas flow, due to the increase in the viscosity of the gas, the pressure drop across the bed increases. Therefore, the high-temperature accumulators are designed so that the pressure loss remains at a fully heated storage and a given exhaust gas flow safely below, for example, 7 mbar.

The control of reinforced edge flows that occur when flowing through solids in solid geometries, is comparatively easy by attaching a temperature-resistant soft layer, such. B. glass wool, to reach the container walls. Glass wool also has the advantage that it is chemically resistant to a process-related below the water and acid dew point (eg in biogas plants from the combustion of hydrogen sulfide). The gas-contacting parts of the high-temperature heat storage should therefore be made of higher quality stainless steels such. B. 1.4571, be made. For parts which are also subject to high mechanical stress, such as the lower support bar and possibly also the gas-permeable carrying system below the support bar, it is also possible to resort to steels which are particularly resistant to sulfuric acid, such as 1.4539.

The main challenge is to control the thermal stresses that arise during heating and cooling of the bed. The linear expansion of individual pebbles is approximately in the range of one percent with a temperature change of 400 Kelvin. As the bed cools, it contracts and there is a risk of individual stones sliding into a deeper level, causing the bed to collapse and compact in the lower part. Upon renewed heating thereby occur in the lower part ever stronger forces due to the thermal expansion of the storage material. After a larger number of alternating cycles, this can lead to a mechanical destruction of the container surrounding the storage mass in stationary heat accumulators.

In mobile heat storage, which are filled, for example, with rather round gravel, it is due solely by transport-related vibrations a continuous loosening of the storage material. Due to the optional conical container walls that expand upwards, the thermal stresses can be dissipated during the heating process upwards, and the loosening caused by transport shocks is favored.

The following example illustrates a variant embodiment of the high-temperature heat accumulator according to the invention: Three conical containers made of stainless steel (eg 1.4571) with a height of 2,300 mm, an upper diameter of 2,000 mm and a lower diameter of 1,500 mm are installed in a thermally insulated container on the inside and filled with a total of 23 tons of gravel. With a load up to an average temperature of 450 ° C and a discharge up to 50 ° C, about 2,300 kWh of heat can be stored. In the event that truck transports of up to 60 tonnes (so-called gigaliners) are approved in the future, the scope of application of all mobile heat storage methods will increase considerably.

The metal construction of mobile high-temperature heat storage after o. G. Example is the same for all sizes of biogas plants and engine types used. Depending on the respective exhaust gas volume flow and the maximum permissible exhaust backpressure different gravel packings are used.

The storage density of the high-temperature heat storage per container charge according to the invention is about 100 kWh per ton of storage mass, regardless of the legally permissible limit of transport tonnage, about 50 percent higher than the low-temperature heat storage according to the invention, and thus in the range of market-available latent heat storage on sodium acetate basis.

The principle of mobile sensitive heat storage according to the invention will be explained in more detail with reference to the drawings.

1 and 2 show the charging and discharging with a mobile low-temperature heat storage according to the invention;

3 to 5 show alternative embodiments of a low-temperature heat accumulator with separating piston according to the invention;

6 to 9 show the construction and the arrangement of a separating piston in a low-temperature heat storage according to the invention;

10 to 12 show an embodiment of a low-temperature heat accumulator with hose separation according to the invention, wherein different filling states are shown;

13 to 15 show the arrangement of a separation tube in a low-temperature heat storage according to the invention;

16 to 23 show alternative embodiments of a low-temperature heat accumulator with hose separation according to the invention;

24 to 27 show the loading and unloading of a mobile storage with solid mineral storage mass according to the invention;

28 and 29 show an embodiment of the mobile storage with solid mineral storage mass according to the invention;

30 to 34 show alternative embodiments of the mobile storage with solid mineral storage mass according to the invention;

In 1 is the loading process of a mobile heat storage for low-temperature heat at a heat source ( 102 ).

At the heat source ( 101 ) is always at least one stationary storage for warm ( 104 ) and cold ( 105 ) Heat storage fluid installed. The cold heat storage fluid is removed from the cold stationary storage tank ( 105 ), at the heat source ( 101 ) and the warm stationary storage ( 104 ). Alternative to the two stationary memories shown here ( 104 . 105 ) with variable levels could z. B. also a stationary storage with a separation, similar to that of the mobile storage ( 101 ) be used. The description of the charging and discharging process is exemplary based on two stationary storage at the heat source ( 102 ) and the heat sink ( 108 ) and also includes other versions of the stationary storage, without these being explicitly mentioned.

A memory ( 101 ) for receiving cold and warm heat storage fluid is mounted on a chassis and loaded with cold heat storage fluid. For charging, the storage at the heat source is connected to the two stationary storage tanks. About the port A is through the pump ( 109 ) cold heat storage fluid from the mobile storage ( 101 ) into the stationary storage for cold fluid ( 105 ) pumped. As a result, the insulating piston ( 113 ) to the suction side (in 1 to the left) and draws warm heat storage fluid from the stationary storage ( 104 ) over the port B in the mobile storage. The pump ( 109 ) is mounted on the cold side for material protection. The charging process is completed when the insulating piston on Closing bottom of the mobile storage has arrived and is completely filled with warm heat storage fluid.

In 2 is the unloading process of the mobile heat accumulator at the heat sink ( 108 ). For this purpose, from the stationary storage ( 107 ) pumped the cold fluid through the port B in the mobile storage. The inflowing cold fluid pushes the insulating piston ( 113 ) to the left and thus displaces the warm fluid from the mobile storage, so that this via the port A in the warm stationary storage ( 106 ) is pressed. At the end of the unloading process, the insulating piston is in the end position on the left-hand end of the floor and the mobile storage tank is completely filled with cold fluid. Even when discharging the pump ( 109 ) for material protection on the cold side. From the heat sink ( 108 ) is warm heat storage fluid from the stationary storage ( 106 ) and after removal of the thermal energy in the cold stationary storage ( 107 ) to hand over.

In 3 to 5 Three variants of the memory are shown with different insulating piston. The profile of the insulating piston ( 113 ) corresponds to that of the end plates of the inner container ( 110 ), so that in the end position of the insulating piston remains only a minimal residual volume between the piston and the end floor. The profile of pistons and trays can z. B. be executed as a cone, dished bottom or flat. As a preferred variant, the in 3 shown type with flat conical bottoms and piston sides viewed as these cones are both inexpensive to manufacture and pressure-stable. At the top of the inner container ( 110 ) is a vent pipe ( 116 ) to prevent accumulation of air in the storage tank. At the bottom of the inner container ( 110 ) is a drain connection with a frost protection ( 117 ), which prevents during winter breaks, that the memory freezes and is damaged by the volumetric expansion of the ice.

3 : Representation of the memory for holding cold and warm heat storage fluid. The inner container ( 110 ) with thermal insulation ( 111 ) has at least two openings A and B, for filling or for removing the heat storage fluid. The insulation is covered by a panel ( 112 ) protected. The heat-insulated storage is by the sliding and sealed against the storage wall indented insulating piston ( 113 ) divided into two thermally decoupled chambers. The total volume of the two chambers is always the same, so that the heat storage fluid can be removed through the one opening and passed through the other opening back into the memory. Is the piston z. B. far left, the left chamber is empty and the right has its maximum volume. Now, if heat storage fluid is pumped through opening A in the memory, the heat storage fluid exits the right chamber through opening B. The indented shape of the insulating piston has the advantage that at comparatively small piston volume, the contact surface to the inner container ( 110 ) is large, so that a wedging of the piston can be counteracted by the movement.

4 : Representation of the memory analog to 3 , but with bulged insulating piston ( 114 ) and corresponding end plates of the inner container ( 110 ). The vaults can z. B. cone-shaped or formed as a dished bottom.

5 : Representation of the memory analog to 3 , but with flat insulating piston ( 115 ) and flat bottom plates of the inner container ( 110 ).

In 6 is the left part of the mobile memory of 3 shown in more detail. The indented insulating piston ( 113 ) consists of a cylindrical piece of pipe ( 141 ) and preferably from flat cones ( 142 ). Preferably, the piston is made of stainless steel and can be stabilized with stiffening ribs not explicitly shown here. The piston can alternatively also plastic, z. B. GFK be made with foam core. The through the pipe section and the cones ( 142 ) formed interior of the piston ( 113 ) may be both hollow and foamed, for example, with polyurethane. In order to minimize the forces that the insulating piston on the centering ( 155 ) on the inner container ( 110 ) and impede the movement during charging, the insulating piston has weights ( 143 ). By these weights, the average density of the piston can be adjusted so that it corresponds to the density of the heat storage fluid. Ie. at a density of about 1,000 kg / m ^3, the piston does not float within or fall within the reservoir so that it can easily move during loading.

7 illustrates the disassembly of in 6 illustrated components. After removing the side insulating cap ( 159 ), the flange connection ( 150 . 152 ) and so the flanged end floor ( 150 ) with the conical filler ( 151 ) are removed.

In 8th is the side view from the left of 7 (viewed from the direction Z). The isolation of the cylindrical storage part ( 158 ) protrudes beyond the sealing surface of the open housing flange ( 152 ). Within the housing flange ( 152 ), the bolted outer circumferential seal ( 159 ) visible, noticeable. The circumferential bearing ring, which transmits the screw forces on the seal, is not shown here for clarity in the diagram. This seal consists of a temperature resistant flexible material, such as NBR. At least three points (here: at six points) on the circumference are spring-mounted centerings ( 155 ), which the insulating piston even in production-related Unrundheiten of inner container ( 110 ) and cylindrical tube piece of the piston ( 141 ) in the middle. The circumferential seals are designed with such a large oversize that they also compensate for the discontinuities and minimize the leakage rate of the heat storage fluid between the warm and cold sides.

In 9 is the in 7 illustrated spring-guided centering ( 155 ) in detail. Shown are the insulating flask ( 113 ) with cone ( 142 ), Balance weight ( 143 ), cylindrical tube piece ( 141 ) and the outer circumferential seal ( 159 ) by screws ( 167 ) is attached. In addition to the outer seal ( 159 ) can also inner seals ( 166 ) by screws ( 168 ) be attached. The insulating piston ( 113 ) is replaced by roles ( 160 ), which are exemplified here as a spring-mounted ball rollers (see also: www.tretter.de) out. The ball rollers are movable in a guide ( 161 ) stored. They are replaced by disc springs ( 162 ) by a screw-in ( 163 ) and adjusted, against the cylindrical part of the inner container ( 110 ), so that the insulating piston ( 113 ) can be performed centered in the inner container despite production-related Unrundheiten.

In 10 to 12 is a variant of the separation of the hot and cold heat storage fluid with a flexible hose ( 170 ). The hose separates the interior ( 171 ) from the mantle space ( 172 ) of the memory. The hose ( 170 ) consists of a temperature-resistant liquid-impermeable material, such. B. a non-stretchy siliconized polyester fabric, as it is used for airbags of cars (420 g / m ² basis weight, double-sided silicone layer of 90 g / m ² ). To reduce the heat transfer during charging, this fabric can be made double and optionally additionally provided with an internal additional temperature-resistant flexible insulating layer (eg felt). For this embodiment, a one-sided silicone-coated fabric can be used.

The tube has the same diameter as the cylindrical inner container ( 110 ) and a length corresponding to the sum of the length of the cylindrical inner container plus the diameter of the inner container plus a safety margin of a few percent. Due to this length dimension, the hose can be filled when the jacket space ( 172 ), so that the interior ( 171 ) is completely emptied without major forces on the attachment points ( 173 ) from the hose on the inner container ( 110 ) occur.

In particular, in all variants of the mobile storage with hose separation shown below, the delivery of large customers with each complete discharge at the heat sink is desirable. A partial emptying, as z. B. in the supply of several small heat consumers, such. B. homes, would take place, would result from the longer residence time of hot and cold heat transfer fluid in the mobile storage greater heat transfer through the tubing result. Through short times and complete transfer, the loss of transportable heat through temperature compensation via the tubing can be kept below five percent.

In 10 is the mobile storage unit with conical bottom plates ( 150 . 151 ) and chamber separation through a flexible hose ( 170 ) during a transshipment process. There is heat storage fluid both in the interior of the hose ( 171 ) as well as in the mantle space ( 172 ).

In 11 is the interior ( 171 ) completely filled and the shell space ( 172 ) almost completely emptied.

In 12 is the mantle space ( 172 ) completely filled and the interior ( 171 ) is almost completely emptied. The hose ( 170 ) lies against the conical topsoils ( 150 . 151 ), so that in the attachment area ( 173 ) no major forces on the hose occur.

In 13 to 15 is the attachment of the hose ( 170 ) in the memory. The hose ( 170 ) is formed with cup-shaped circle segments ( 174 ) near the housing flange ( 152 ) on the cylindrical part of the inner container ( 110 ), in particular screwed. The cup-shaped circle segments are provided with rounded boundary surfaces, so that the hose is not damaged during the loading process. 13 shows the mobile storage with conical end plates and hose separation in the mounted state, 14 the dismantling of the insulating cap and the bottom plate with conical inner part and the cylindrical part of the inner container ( 110 ) attached hose ( 170 ). 15 shows the side view of the open heat accumulator with mounted hose from the left (viewing direction Z in 14 ). The cup-shaped circle segments for fastening the hose are in 15 shown as loose components near their mounting location.

In 16 to 23 Further variations of the mobile storage with hose separation are shown, which are sub-variants of the in 10 to 12 shown separation with a large hose to understand.

In 16 is a separation of the chambers for hot and cold fluid with two open on each side hoses ( 180 . 181 ), which are mounted through the side connecting pieces. The two unilaterally open hoses are dimensioned so that they can take up the total volume of the mobile storage. An assembly of the two hoses on the cylindrical inner container ( 110 ) analogous to 13 to 15 is also possible without this being shown separately.

17 shows a variation of 16 in which at least one bottom of the unilaterally open tubes ( 180 . 181 ) an insulating layer ( 182 ) is attached to at least one of the hoses to reduce heat transfer during charging.

In 18 is the chamber separation ( 183 ) mounted in the middle of the mobile storage so that it can fill the entire chamber in both end positions. The central mounting can be analogous to that in 14 shown done. Alternatively, the chamber separation can be flanged into a centrally arranged housing flange (not shown here graphically).

19 : Analogous to 16 , but with only one unilaterally open thermally insulated hose ( 184 ). This hose ( 184 ) may consist of a stretchable or a non-stretchable material, but in both cases may fill the total volume of the reservoir. The two chambers for hot and cold heat storage fluid through the inner and outer space of the hose ( 184 ) educated.

20 : Analogous to 16 but with a separate insulating material ( 185 ) between the two unilaterally open tubes ( 180 . 181 ).

21 : Similar 20 , but only one hose ( 186 ) is used, which has more than twice the length of the mobile memory and approximately centrally in at least two places, for. B. with metal braces, is constricted, so that a third chamber ( 187 ), which is filled with insulating material.

22 : Mobile storage with hose separation, in which the separation of the inner container volume by a plurality of flexible on both sides open heat-insulating tubes ( 189 ), which on both sides on each a thermally insulated inner wall ( 188 ) are attached.

23 : Analogous to 22 , but with hoses open on one side ( 190 ), which at its open end on a thermally insulated inner wall ( 188 ) are attached.

In 24 to 27 For example, the loading and unloading of a mobile storage with a solid mineral storage mass is shown.

Three conical gastight containers ( 230 ), inside which the porous heat storage material is located, are, as exemplified in 24 shown in a container ( 231 ) assembled. To reduce heat loss, the three containers and the interior of the container with mineral wool ( 232 ) insulated. The hot exhaust gas of a power generator with internal combustion engine ( 220 ) is introduced via the nozzle A in the left of the three containers, flows through the porous heat storage material ( 233 ) from bottom to top and exits in the upper part of the left tank again. The heat transfer from the hot exhaust gas to the heat storage material is unimpeded by direct gas-solid contact. At the bottom of the three containers is in each case as an additional option, a drain port ( 236 ) for condensate precipitated from the gas during cooling. To protect the internal combustion engine, an additional maximum exhaust backpressure must not be exceeded. As a general guideline, 10 mbar for the entire exhaust system after the silencer can be assumed here. As a basis for design and to take account of pipe losses, the maximum pressure loss across the entire storage material in the heated state, including the flow losses within the mobile storage 7 mbar. As additional safety, there is a safety valve between the combustion engine and the mobile 221 ), which opens at an inadmissibly high pressure loss via the mobile storage, the hot exhaust gas via an emergency chimney ( 222 ) dissipates into the environment and thus protects the motor from damage. 24 shows the mobile memory during the advanced loading process. About the port A is supplied from the internal combustion engine 450 ° C hot exhaust gas in the memory. The storage mass in the left tank has an average temperature of 400 ° C, in the middle tank of 200 ° C, while the storage mass in the left tank still has an average temperature of about 50 ° C. The exhaust gas is emitted via a chimney ( 223 ) delivered to the environment.

In 24 to 26 are the three containers ( 230 ) connected in series for example. Likewise, the containers can be switched in parallel, as in 27 shown. Due to the parallel connection, the inflow velocity of the exhaust gas is reduced to the storage material, so that at the same charge the pressure loss over the Storage material decreases significantly. This reduction in the pressure loss in parallel connection of the three containers can be counteracted by the choice of a smaller grain diameter of the storage material.

By way of example, for a power generator with an electrical power of 500 kW, in which the pressure loss over the storage material should be about 7 mbar, in series connection of the three containers a gravel with Kornduchmessern from 32 to 38 mm and parallel connection a gravel with a grain diameter of 3 up to 7 mm can be used.

25 shows the same arrangement as 24 , but at the end of the charging process. The left storage mass has almost reached the inlet temperature of the exhaust gas. The temperature of the right-hand storage mass is only slightly below the inlet temperature at the connection A, so that over the chimney ( 223 ) 400 ° C hot exhaust gas is discharged to the environment. With a further progressive heating of the three storage masses, the ratio of exhaust gas heat of the internal combustion engine to the stored heat deteriorates due to the exhaust gas loss. To achieve a high storage efficiency, therefore, the charging of the entire storage mass should not be carried out to the exhaust gas temperature. As a guideline for the end of charge may apply if the gas temperature at port B measured in degrees Celsius is about 85 to 90 percent of the temperature measured in degrees Celsius at port A.

Should it be necessary from a legal point of view to maintain a prescribed minimum exhaust gas temperature in the chimney, for example 60 K above the water dew point, this may necessitate a reheating of the cold exhaust gas leaving the storage tank. The outlet temperatures of the exhaust gas (eg. 24 , Nozzle B) are at the beginning of the charging of a cooled to ambient temperature memory typically in the range of about 40 to 65 ° C and rise during the loading process to near the exhaust gas temperature at the inlet nozzle (A). If a reheating of the exhaust gas to, for example, at least 120 ° C prescribed, then the exhaust gas exiting from the store exhaust should be heated until the memory is charged so far that the outlet temperature at port B exceeds this minimum value 120 ° C.

• a) Mit Abwärme des Verbrennungsmotors
• – Einstufig über Erwärmung des Abgases über einen Ölkühler (Abgas-Motoröl-Wärmetauscher) mit Motoröltemperaturen deutlich über 150°C
• – Zweistufig: Vorwärmung des Abgases mit Kühlwasser auf etwa 80°C. Zur weiteren Aufheizung kann ein Teilvolumenstrom des heißen Abgases gemäß b) erfolgen
• b) Durch Beimischung eines Teilvolumenstroms des heißen Abgases vom Stutzen A, der im Bypass um den Wärmespeicher herumgeführt wird und dem kalten Abgas vor dem Eintritt in den Kamin (223) beigemischt wird.

The reheating can be done in principle in different ways:

• a) With waste heat of the internal combustion engine
• - One-stage heating of the exhaust gas via an oil cooler (exhaust gas engine oil heat exchanger) with engine oil temperatures well above 150 ° C
• - Two-stage: Preheating the exhaust gas with cooling water to about 80 ° C. For further heating, a partial volume flow of the hot exhaust gas according to b) can take place
• b) By admixing a partial volume flow of the hot exhaust gas from the port A, which is bypassed around the heat storage in the bypass and the cold exhaust gas before entering the chimney ( 223 ) is added.

In general, a reheating of the exhaust gases before entering the chimney significantly increases the operational expenditure on equipment. In particular, a reheating of the cold exhaust gas with a partial volume flow of the hot exhaust gas counteracts the idea according to the invention, since the charging of the memory takes longer and therefore a total of less of the exhaust heat can be used for the delivery to the heat customer. From the point of view of emission and immission protection, no reduction of this is achieved, since the reheating the condensation from the fireplace is spatially relocated to the atmosphere, where it takes place again when cooling the exhaust gases.

If a reheating of the exhaust gases is not necessarily prescribed by an approval authority, it should in any case be waived from an ecological and economic point of view

In general, to discharge the mobile memory, regardless of whether the containers are connected in parallel or in series, the cooler air should be introduced via the nozzle B (gas outlet nozzle during charging) in the memory. As a result, the air first strikes the cooler part of the storage material and can continue to heat up in the course of the flow. The exit temperature of the hot air is thus maximized and the heat transfer in the heat exchanger ( 234 ), so that it can be dimensioned smaller.

In 26 is the discharge of the mobile memory at a heat sink ( 108 ). The discharge is analogous to the loading also in direct gas-solid contact. By way of example, the discharge takes place here in series connected containers, but it can, as already mentioned, even with parallel connected containers done (using finer bulk material to maintain the pressure loss). Via a fan ( 235 ) air is supplied by way of example with a temperature of 50 to 100 ° C via the port B the heated mobile storage. The fan is mounted on the cold side for material protection. As it flows through the heated storage mass, it heats up to almost the maximum temperature of the memory. 27 shows an example of the discharge of the mobile storage with parallel connected gas-tight inner containers. As well in 26 as well as in 27 the air exits the storage tank at 420 ° C and releases its heat in a gas-liquid heat exchanger ( 234 ), from which the heat sink ( 108 ) is supplied.

28 : Representation of the memory according to the invention for loading and unloading a solid storage medium with heat energy by direct gas contact. The memory has a fixed storage medium ( 233 ) with inner pore or gas system, which is traversed by the heat transfer gas via the inlet A to the outlet B, a gas-tight casing (inner container, 230 ) with soft material on the inside ( 240 ), such. As glass wool to reduce the Randgängigkeit the gas flow, and here exemplified all sides mounted force-bearing thermal decoupling ( 241 ). The gastight casing ( 230 ) ensures that introduced via the nozzle A heat transfer gas directed through the solid heat storage medium ( 233 ) and exits at port B, without leakage into the insulation ( 232 ) or the environment may occur. The inflow and outflow surfaces ( 242 . 243 ) can be designed, for example, as grates, perforated plates or grids. The weight of the heat storage material is transferred via the lower flow grate ( 242 ), the lower gas-permeable support structure ( 244 ), the force-carrying thermal decouplings ( 241 ) on the outer container shell ( 231 ) transfer. At the bottom of the gastight casing ( 230 ) is a drain port ( 236 ) is attached to the cooling of the gas accumulating condensate.

The inversion of the flow direction of the gas from port B to port A is also without explicit graphical representation part of the invention.

29 shows the structure of the lower Auflagerostes in more detail. The lower support grid ( 242 ) consists for example of angle profiles made of stainless steel, which are mounted with a sufficient distance for the gas passage to each other. The support grid is fixed to the gas-permeable support structure ( 244 ) connected. There is a multi-layered layer of large stones ( 246 ), which are so large that they can not fall through the support shelf and that through a stainless steel net ( 245 ) are held firmly on the support bottom. This fixation of the large stones prevents these from floating due to transport-related vibrations in the finer-grained layer of the storage material, which would ultimately trickle the fine-grained layer through the Auflagerost.

The size ratios of the stones are to be chosen so that the fine-grained storage material can not trickle through the pores of the large stones. In the case of particularly fine-grained storage material, it is also possible to add a second layer with stones of medium grain size (not shown here).

In 30 is a variant of the discharge of the memory with a solid storage material represented by a cold air-sucking fan ( 247 ), in which the hot air is used directly, ie without heat exchanger and circulation.

In 31 to 34 are shown variation of the memory according to the invention with a solid memory material.

In 31 is a central partition ( 250 ), so that the gas within a gas-tight container ( 230 ) is deflected. The longer path of the gas through the storage material can be used to increase the pressure loss.

In 32 There is a horizontal flow through the solid storage material. The gas-tight container can be designed both round and square. The lateral boundary gratings ( 251 . 253 ) hold the heat storage materials in the form and can be performed as in the vertical variants or as laterally open lamellar or Jalousieroste or obliquely set flat iron, can be reduced by the thermal stresses of the heat storage material by lateral movement of the bed.

In 33 is the flow through several parallel chambers ( 253 ) represented by memory material.

34 shows a radially symmetrical structure with concentric inlet and Abströmrosten ( 254 . 255 ), which hold the bed of heat storage material in the form.

A reversal of the flow direction (between the inlet and outlet ports A and B) is in all the drawings shown without explicit graphical representation part of the invention.

Claims (12)

Method for heat transfer, wherein a heat storage medium in a transportable container ( 101 ) is transported from a heat source to a heat sink, wherein the container ( 101 ) Connecting piece for a loading and unloading, characterized in that for the storage of sensitive heat at temperatures below 100 ° C water is used as a fluid heat storage medium, in that a container with a multi-chamber system is used for separately receiving warm (charged) and cooled (discharged) water, the chambers each being variable in their volume so that the total volume of all the chambers is constant, each chamber having at least one connecting piece in Fluid communication is, wherein the filling and emptying of the chambers takes place at least temporarily simultaneously. A method for mobile heat storage according to claim 1, characterized in that a piston ( 113 ; 114 ; 115 ) is used as a slidable separation between the chambers in the container, said piston along its circumference by resiliently mounted rollers ( 160 ), in particular ball rollers, is guided, which are supported on an inner container wall. A method for mobile heat storage according to claim 1 or 2, characterized in that at least one of the chambers in the container by a flexible hose ( 170 ) is formed, whose volume is variable during filling and emptying. Method for mobile heat storage according to one of claims 1 to 3, characterized in that the filling and emptying of the chambers of the transportable container with a pumping rate of 1 to 10 m ³ / min, preferably with 3 to 6 m ³ / min. Transportable container for transporting heat from a heat source to a heat sink, the container comprising connecting pieces for loading and unloading, by which it can be filled and emptied with water, characterized in that the container is a multi-chamber system for separately receiving warm (charged) and cooled (discharged) water, the chambers each being variable in volume such that the total volume of all the chambers is constant, each chamber being in fluid communication with at least one spigot, and either one piston ( 113 ; 114 ; 115 ) is used as a slidable separation between the chambers in the container, said piston along its circumference by resiliently mounted rollers ( 160 ), in particular ball rollers, which are supported on an inner container wall, or at least one of the chambers in the container by a flexible hose ( 170 ) is formed, whose volume is variable during filling and emptying. A method of heat transfer, wherein a heat storage medium is transported in a transportable container from a heat source to a heat sink, wherein the container connections for gas charging and gas removal, characterized in that for the storage of sensible heat at temperatures above 100 ° C a solid, porous, in particular mineral storage material ( 233 ), which is introduced in the container as a bed, wherein the bed is in fluid communication with the terminals, wherein for storing or removal of high temperature heat above 100 ° C, gas is passed through the terminals through the bed, so the storage material in direct gas-solid contact is thermally loaded or unloaded. A method for mobile heat storage according to claim 6, characterized in that for the storage of heat at temperatures up to 550 ° C gravel is used as a heat storage material. Mobile heat storage method according to claim 6 or 7, characterized in that cold exhaust gas ( 24 , Port B) is heated with the waste heat of the internal combustion engine or with a partial volume flow of the hot exhaust gas (port A) until a predetermined minimum gas temperature for the entry into the chimney ( 223 ) is reached Method for mobile heat storage according to claim 6 or 7, characterized in that for the charging of the solid storage material, the exhaust gas of an internal combustion engine is used, wherein the particle size distribution of the storage material is selected such that the differential pressure in the flow through the fully heated bed and the installed exhaust system in the range of 30 to 95 percent, preferably at 50 to 80 percent of the maximum allowable exhaust backpressure of the internal combustion engine. A transportable container for transporting heat from a heat source to a heat sink, the container having connection ports for loading and unloading, characterized in that the container has at least one gas-tight chamber containing a bed of solid, porous storage material, wherein the chamber in Fluid connection with the connecting piece is, so that the bed of introduced gas can be flowed through. A container according to claim 10, wherein the chamber ( 230 ) has at least one downwardly tapered conical section, which can be traversed in height and the gas Solid contact allows, so that the heat stresses occurring during heating and cooling are reduced by the conical container geometry upwards. Container according to claim 10 or 11, wherein the gas-tight chambers on their side facing the storage medium of the inner wall with a soft temperature-resistant material, in particular with artificial mineral wool ( 232 ), to reduce the Randgängigkeit the gas flow are lined.

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