WO2002012814A1

WO2002012814A1 - Latent heat storage device

Info

Publication number: WO2002012814A1
Application number: PCT/EP2001/008974
Authority: WO
Inventors: Alfred Pommerenke
Original assignee: Globe Thermal Energy Ag
Priority date: 2000-08-03
Filing date: 2001-08-02
Publication date: 2002-02-14

Abstract

The latent heat storage device (100) comprises a first storage container (1) which is filled with a latent storage medium and preferably with a heat transfer medium, and a second storage container (2) which is filled with a secondary medium. A heat exchanger (5) for heating or cooling the latent storage medium is located in said first storage container (1), which is itself located inside the second, outer storage container (2). The outside of the inner storage container is connected to the secondary medium. This results in an optimisation of the storage capacity and a reduction of the inertia of the latent heat storage device (100) while maintaining a simple construction.

Description

Latent heat storage

The invention relates to a latent heat accumulator of claims 1, 23 and 29 and a method of the type corresponding to claims 17 and 26.

The latent heat stores in question are heat stores in which substances (latent storage media) store or emit energy in the form of heat when their physical state changes. In particular, use is made of the solid-liquid conversion. The heat of fusion or solidification is called latent (hidden) heat.

It is known that by using heat stores with latent storage media, such as salt hydrates or paraffins, up to five times higher heat storage capacity can be achieved compared to water-operated heat stores.

Such latent heat storage devices are usually fed by means of heat coming from solar systems, which has the advantage of using the heat obtained directly and makes sense for ecological reasons.

Such a latent heat store is described, for example, in DE 199 53 113

C3 disclosed. This latent heat storage has a storage tank, which is filled with a salt hydrate as latent storage medium, in which a heat exchanger for heating or cooling a secondary medium is arranged. The heat exchanger here has a plurality of heat-conducting plates which are spaced apart from one another by gaps and which are in thermal contact with the secondary medium.

A disadvantage of the conventional latent heat storage is that due to their design they only provide a part of the possible performance, since the salt hydrate cannot be melted or solidified quickly and evenly, so that the known systems have a great sluggishness in dispensing and Have absorption of heat. They are not able to absorb this quickly when there is a large amount of heat, which is provided, for example, by solar systems when the sun is shining. This means that part of the existing heat is lost.

Depending on the season, an additional heating source is required for heat storage systems operated by solar systems if the solar radiation is no longer sufficient to maintain the necessary temperature of the latent storage medium. If electric power is used for this purpose, this should advantageously be done at times when the electricity tariff is low, i.e. H. mainly at night. The previously known systems can only do this to a limited extent because of the inertia, especially since part of the energy is lost through the inertia.

On the other hand, the systems can reverse the stored

Heat at peak loads, such as occurs when showering or filling bathtubs, cannot be released to the water or secondary medium quickly enough. As a result, the water is not heated evenly and there are undesirable temperature fluctuations at the consumer.

In part, these problems can be reduced by the known use of a heat transfer medium, such as oil in particular. The oil is through the latent storage medium is pumped through and absorbs the heat or distributes it more evenly. The problem here, however, is that the thermal expansion of the oil and / or aggregate-related expansion of the latent storage medium means that there must be space available in the conventional heat stores. Such a change in volume can be up to approx. 12%. This results in an unfavorable performance in terms of volume. In addition, due to the change in volume, breathing lines for pressure equalization are required, which are connected to the free atmosphere. Due to the "open" construction, which, for. B. from the magazine "Sl Information, Sanitary Heating Climate", July 1996, pages 19-21 is known, water can penetrate, which on the one hand corrosion and on the other hand a change in properties (z. B. melting point lowering by Contamination) of the latent storage medium caused by water retention. Furthermore, pumps are required for the circulation of the oil in the conventional systems, which makes the structure complex and requires the use of electrical energy to operate the pumps.

The object of the invention is therefore to achieve an optimization of the storage capacity and a reduction in the inertia of a latent heat store with a simple structure.

This object is achieved in its apparatus aspect by the invention reproduced in claim 1.

Characterized in that the latent heat storage comprises a first storage container which is filled with a latent storage medium and a heat transfer medium and a second storage container which is filled with a secondary medium, wherein a heat exchanger is arranged in the first storage container for heating or cooling the latent storage medium , the first storage container is arranged within the second, outer storage container and the outside of the inner storage container is in connection with the secondary medium, it is possible to a large extent Load transfer to the secondary medium and thus to achieve a complete or at least better use of thermal energy, especially solar energy.

This is namely heated via the outside of the inner storage container and is then available to the consumer. Due to the large volume of the secondary medium, sufficient warm secondary medium is always available. The large surface of the outside of the inner storage container heats up the secondary medium quickly and, due to its low density, rises upwards for removal. The problem of inertia of the latent storage medium is also solved, since the heating (or cooling) of the secondary medium takes place quickly, so that it can be used to operate the consumer without temperature fluctuations. The secondary medium can be water, for example. The inner storage container is thus via its outside in a heat-transmitting, in particular heat-conducting connection to the secondary medium surrounding it.

It is favorable if a secondary medium flows through the heat exchanger arranged in the inner storage container. Then two separate circuits can be used to operate the latent heat storage: a first circuit for heating the latent storage medium and a second circuit for supplying the consumers. A connection of the circuits for better heat utilization is also conceivable. Then the secondary medium first flows through the heat exchanger for heating the latent storage medium and then reaches the second, outer storage container for consumption.

The heat exchanger arranged in the inner storage container is advantageously a tube heat exchanger and advantageously comprises at least one approximately vertically arranged tube. A separate arrangement of the tubes is also advantageous. So through the large areas particularly fast and complete melting of the latent storage medium is achieved without so-called "dead" corners. This is supported by the wall of the inner storage tank, which immediately transfers the heat to the secondary medium.

A coil-shaped arrangement of the tubes is also conceivable. An even larger surface area and thus better heat transfer to the latent storage medium is achieved if the tubes are provided with heat conducting plates.

If heat is supplied and / or extracted via the secondary medium in the second, outer storage tank, reheating can be carried out if the temperature of the solar system drops due to the season. The heat is then immediately available and a short heating-up time is sufficient. For this purpose, the secondary medium present in the second, outer storage container can advantageously be heated by suitable means, these advantageously comprising a heating rod which is surrounded by the secondary medium and is preferably operated electrically, the heating rod being arranged either inside or outside the second storage container. This will create a

Allows use of the times of the low electricity tariff. If the heating source is located outside the storage tank, it can contain a pump for circulation and the storage tank does not have to be emptied for maintenance or decalcification. It is also conceivable to operate the means via a heat pump or via electrical energy from solar cells that is temporarily stored in a battery.

If an expansion tank communicating with the inner storage tank is arranged outside the latent heat store, a breathing line to the outside can be dispensed with, so that no moisture penetrates into the system despite a change in volume of the latent storage medium and / or the thermal oil. This makes it possible to use simple materials. The latent storage medium also retains its properties. Furthermore, complete use of the storage space is achieved, since even if the latent storage medium crystallizes completely, the upper part of the storage device remains filled with heat transfer medium and is charged when heat enters. No expansion space must be provided within the memory, so that the capacity of the memory increases with the same total manipulated variable.

The state of charge or degree of saturation of the store can be determined via the fill level of the heat transfer medium, which is displaced when the volume changes, so that a fill level indicator is provided for the inner store container. This is preferably arranged on the expansion tank.

Since the fill level correlates with the state of charge of the storage tank, the supply of heat in the inner storage tank can be regulated via the fill level display. This can be done, for example, simply by means of a pressure meter or a level meter, such as a float.

It is expedient if an external heat exchanger through which the secondary medium (for example water) flows through from the second, outer storage container is provided. Then the secondary medium itself can be used for heating purposes and the second heat exchanger for domestic water heating such as hot water preparation. This makes it possible to decouple the heating from the hot water preparation. This is due to the relative temperature constancy of the flow and return of a heater from

Advantage.

If pressure compensation means are provided for the secondary media, which are preferably designed as pressure compensation containers, the thermal expansion of the secondary means is possible in a closed circuit.

To large capacities such. B. to provide for larger residential units, multiple latent heat storage can be connected to a storage battery and the secondary media flow through the first heat exchanger and / or the second storage container in series and / or in parallel, which results in particularly good use of the thermal energy.

In its procedural aspect, the task is claimed by the

17 reproduced procedures solved.

Da, the method for latent heat storage and release, in which a secondary medium is heated or cooled by a latent heat storage, which consists of a first storage container that is filled with a latent storage medium and a heat transfer medium, and from a second storage container that is filled with the secondary medium , There is, wherein a heat exchanger arranged in the first storage container heats or cools the latent storage medium, the first storage container is arranged inside the second, outer storage container, so that the

Heat transfer between the latent storage medium and the secondary medium takes place via the outside of the inner storage container, can - as already mentioned above - largely compensate for the inertia of the latent storage medium by shifting the load onto the secondary medium and thus a complete or at least better utilization of the

Thermal energy, in particular solar energy can be achieved because the heating (or cooling) of the secondary medium is carried out faster, so that it can be used to operate the consumer without temperature fluctuations. The heat exchange between the latent storage medium in the inner storage container and the secondary medium takes place continuously via the wall of the inner storage container, which is in contact with the secondary medium.

If the heat is supplied and / or removed by a suitable heating medium or a consumer via the secondary medium, it is possible in a simple manner if necessary, such as. B. in winter, when the heating power drops due to the decrease in regenerative energies for feeding the latent heat storage, the storage by conventional energy sources reheat. The secondary medium quickly absorbs the heat and then transfers it to the latent storage medium, which itself absorbs and stores the heat slowly due to its inertia. Thus, the secondary medium is immediately available for consumption at the desired temperature and at the same time the memory is fed, so that optimal use of the heat supplied is guaranteed at all times.

The heat transfer medium can expediently expand into a compensating container communicating with the inner storage container, so that the entire volume of the storage unit can be used for heat storage despite the volume changes occurring in the latent storage medium and the heat transfer medium. Furthermore, a system can be operated in a closed manner, so that environmental influences, in particular water, do not adversely affect its operation.

A level indicator is preferably used to determine the degree of saturation of the latent heat store, which is usually arranged in the expansion tank. In addition to the advantages mentioned above, it is thus achieved that the storage capacity is known at all times. This is important because reheating with electricity or other heat sources, such as a charcoal stove, must not lead to the full use of the storage capacity, because otherwise there would not be enough capacity for solar system operation and this would remain unused, which is for energy and ecological reasons is undesirable.

In this context, it is therefore advantageous if the heat supply and / or the removal in or from the inner storage container is regulated via the fill level indicator. Then the heat supply is controlled directly via the saturation level of the system. This is thus in a simple manner. B. by a swimmer who actuates a switch at a certain swimming height, which switches off the "external" heat supply, possible. This procedure can also limit the maximum possible charging or discharging of the memory. Depending on the latent storage medium used, the memory may not exceed or fall below certain temperatures, since otherwise the latent storage medium may be damaged.

In the case of the conventional latent heat stores, a heat transfer medium, such as in particular oil, is used in order to ensure good heat transfer from or to the latent storage medium. The oil is pumped through the latent storage medium and absorbs the heat or distributes it more evenly.

However, as already mentioned above, it is problematic that the thermal expansion of the oil and / or aggregate-related expansion of the latent storage medium means that there must be space available in the conventional heat stores. Such a change in volume occurs regardless of the design of the latent memory.

Another object of the invention is therefore to achieve an optimization of the storage capacity of a latent heat storage regardless of the structure.

This object is achieved in its apparatus aspect by the invention reproduced in claim 23.

The fact that - preferably outside the latent heat store - a compensating tank communicating with the storage tank is dispensed with, there is no need for a breathing line to the outside, so that despite a change in volume of the latent storage medium and / or the thermal oil, no moisture penetrates into the system. This makes it possible to use simple materials. The latent storage medium also retains its properties. Furthermore, a complete use of space in the memory is achieved, since even with complete crystallization of the latent storage medium, the upper part of the memory remains filled with heat transfer medium and at Entry of heat is charged. No expansion space must be provided within the memory, so that the capacity of the memory increases with the same total manipulated variable.

The state of charge or degree of saturation of the memory can be determined via the fill level of the heat transfer medium, which is displaced when the volume changes, so that a fill level indicator is preferably provided. This is preferably arranged on the expansion tank.

In its procedural aspect, this object is achieved by the invention set out in claim 26.

The heat transfer medium can then expediently expand into a compensating container communicating with the inner storage container, so that the entire volume of the storage unit can be used for heat storage despite the volume changes occurring in the latent storage medium and the heat transfer medium. Furthermore, a system can be operated in a closed manner, so that environmental influences, in particular water, do not adversely affect its operation.

A level indicator is preferably used to determine the degree of saturation of the latent heat store, which is usually arranged in the expansion tank. In addition to the advantages mentioned above, it is thus achieved that the storage capacity is known at all times. This is important because heating with electricity or other heat sources, such as a charcoal stove, must not lead to the full utilization of the storage capacity, because otherwise insufficient capacity for the operation of the solar system would exist and this would remain unused, which is undesirable for energetic and ecological reasons.

In this context, it is therefore advantageous if the heat supply and / or the removal in or from the inner storage container is regulated via the fill level indicator. Then the heat supply is controlled directly via the saturation level of the system. This is thus in a simple manner, for. B. possible by a float, who actuates a switch at a certain swimming height, which switches off the "external" heat supply. This method can also be used to limit the maximum possible charging or discharging of the memory. Depending on the latent storage medium used, the memory may not exceed or fall below certain temperatures, since otherwise the latent storage medium may be damaged.

In conventional latent heat storage, the secondary medium is used both for loading and unloading the storage. Simultaneous loading and unloading, i.e. H. simultaneous feeding in of heat and dissipation of the heat to consumers cannot take place. This would require external means that switch the secondary medium depending on the operation. However, this is uneconomical because part of the heat from the solar system is lost when it is not used.

When a heater and a hot water supply are operated in parallel by means of such a latent heat store, this can only be used unfavorably, since the heating operation places different requirements on the hot water preparation. The forward and return flow of modern heating systems show a relatively small difference in temperature, the energy required by the heating systems is comparatively constant over time, ie rapid temperature changes in the heating medium are not necessary. In contrast, a high temperature is required for hot water preparation, which should be available quickly. These different requirements can be met with the known latent heat storage can not be met or only met in a cumbersome manner.

Due to this inertia, the conventional systems cannot release the stored heat to the water or secondary medium quickly enough during peak loads, such as occur, for example, when showering or filling bathtubs. As a result, the water is not heated evenly and there are undesirable temperature fluctuations for the consumer.

A further object of the invention is therefore to provide a latent heat store which can be used simultaneously for heating purposes and for hot water supply, bypassing or reducing the inertia, and yet has a simple structure.

This object is achieved by the invention set out in claim 29.

Because an external heat exchanger through which the secondary medium flows is provided, it is possible to directly add the secondary medium

To be used for heating purposes and indirectly in the second heat exchanger for water heating. This makes it possible to decouple the heating from the hot water preparation. This is advantageous due to the relative temperature constancy of the flow and return of a heater. An extensive compensation of the inertia of the latent storage medium by the

Load transfer to the secondary medium and thus a complete or at least better utilization of the thermal energy required to heat the latent storage medium via an internal heat exchanger, in particular solar energy, can be achieved since the heating (or cooling) of the secondary medium is carried out more quickly, so that it can be used to operate the Heating or the heat exchanger can be used essentially without temperature fluctuations. It is expedient if the storage container is surrounded by a second, outer storage container which is filled with secondary medium, the outside of the inner storage container being connected to the secondary medium and the external heat exchanger flowing through it. The heat exchange between the latent storage medium inside

The storage container and the secondary medium then take place continuously via the wall of the inner storage container, which is in contact with the secondary medium. Due to the large volume of the secondary medium, sufficient warm secondary medium is always available. The large surface of the outside of the inner storage container heats up the secondary medium quickly and, due to its lower density, rises for removal. Water is particularly suitable as the secondary medium.

The heat exchanger is preferably arranged above the latent heat store and the hot secondary medium is fed in approximately perpendicularly from the upper region of the outer storage tank. The cooled secondary medium also runs approximately vertically, but in the lower region of the outer storage container. The external heat exchanger can thus be operated by means of gravity, since the hot secondary medium rises due to its lower density and falls over the outlet after its heat has been released. Pump operation is also possible.

It is expedient if the external heat exchanger is a tubular heat exchanger and it comprises, for example, at least one pipe coil through which process water flows for heating. Then a good heat exchange is possible.

In this context, a coil form of the coil can also be used. Further features, details and advantages of the invention result from the following description of the drawings. Show it:

1 shows a schematic view of an embodiment of a latent heat store according to the invention with external connection;

FIG. 2 shows a further embodiment of a latent heat store corresponding to FIG. 1 with a different external connection;

3 shows a schematic representation of a storage battery using a plurality of latent heat stores according to the invention;

Fig. 4 shows a longitudinal section through the external heat exchanger from Fig. 1 and

Fig. 5 shows a cross section through the external heat exchanger line l-l

Fig. 4.

1 shows a latent heat accumulator designated as a whole by 100. The latent heat store consists of an inner storage container 1 which is filled with a latent storage medium (not shown) and a heat transfer medium (also not shown).

The preferably used latent storage medium sodium acetate offers an ideal melting temperature. It melts at 58.5 ° C and cools, for example, from 63.5 ° C to 48.5 ° C during the transition from the liquid to the solid state, the usable heat content being approx. 100 kWh / m ³ . The proportion of latent heat is around 75%. For comparison, water stores a heat quantity of only 17.4 kWh / m ³ , since it does not change its physical state in this temperature range. This means that up to five times the capacity is achieved. The heat transfer medium is, for example, white oil, which penetrates the latent storage medium and thus for an almost 100 percent heat exchange between see the two substances and accelerates the heat absorption or release.

The inner storage container 1 is completely surrounded by an outer storage container 2, in which there is secondary medium, such as water. This means that the inner storage container 1 hangs freely in the outer storage container 2 and is only connected to it in the upper region via the respective edge zones. The outer storage container 2 also simultaneously represents the housing of the latent heat store. Not shown in FIG. 1, but normally present, is an insulating sleeve surrounding the latent heat store 100 for better thermal insulation.

The latent heat store 100, as well as its inner and outer storage containers have a substantially cylindrical shape, which is rounded both above and below. To set up the device it has on the

Bottom welded feet 3, 3 ', 3 ", which are attached approximately evenly spaced around the circumference. On its upper side, the latent heat storage device 100 has a flanged cover 4, which is provided with several openings for connections to be described.

A heat exchanger 5 projecting from top to bottom into the inner storage container 1 is arranged approximately in the middle. The heat exchanger consists of the actual heat exchanger tube 12, which - viewed from the top downward - initially extends approximately vertically through the housing cover 4, in order to then wind downward in a coil-like manner.

Then, ie after the last turn, the heat exchanger tube 12 extends vertically upward approximately parallel to the first approximately vertical region through the cover 4. The heat exchanger 5 is flowed through by a further secondary medium which flows through the line 9 in the direction of the arrow into the heat exchanger and after flowing through the coil-shaped area leaves the heat exchanger via line 10. To control the temperature of the emerging secondary medium, a thermometer 11 is attached to line 10. With the secondary medium, which ches flows through the heat exchanger 5, it can also be water.

The secondary medium heated, for example, by regenerative energies therefore flows through the line 9 into the heat exchanger 5 and gives in

Area of its coil-shaped section transfers its heat to the latent storage medium or to the white oil and then leaves the heat exchanger via line 10. The heat absorbed by the latent storage means is conducted radially outward from the area of heat exchanger 5 and reaches the wall of the Storage container 1 to the secondary medium stored in the outer storage container 2 and gives off its heat there. The secondary medium of the outer storage container 2 is therefore only heated indirectly.

To supply the outer storage tank 2 with cold water, a corresponding line 7 for the cold water supply is provided in its lower region. The cold water enters the heat accumulator in the direction of the arrow below and is heated by the latent storage medium in the outer storage container 2 via the outer wall of the storage container 1. Due to its changing density, the warm water rises and can leave the heat accumulator 100 via line 6 at an upper connection. The line 6 is provided with a valve 13 for flow control. The heated water or secondary medium located in line 6 can now be used to supply various consumers. In addition, heaters come into consideration. Then the heating water runs after flowing through the heating via line 7 back into the outer storage tank. This is particularly favorable in terms of energy, as is known that the temperatures of the heating flow and return differ only slightly.

However, other use of the heated water is also conceivable. In the example shown in FIG. 1, hotter service water - as is required, for example, for bathing - is generated by means of an external heat exchanger 50. This is via a feed line 51, which leads from the upper part of the outer storage container 2 into the heat exchanger 50, and with a corresponding return line 52, which leads the secondary medium cooled in the heat exchanger 50 back into the lower region of the outer storage container 2 of the latent heat store 100, connected. The heat exchanger 50 works according to the countercurrent principle, for which cold water is supplied in its lower region via a line 53, which is then heated in the heat exchanger 50 on its way up by the secondary medium from the latent heat store and leaves the heat exchanger 50 via the hot water line 54. The cooling secondary medium from the outer storage container 2 flows through the line 52 back into it, so that the difference in density means that a separate pump for operating the heat exchanger 50 can be dispensed with if necessary. The secondary medium flowing back into the outer storage container 2, like the colder secondary medium entering via the supply line 7, is heated again via the inner storage container 1 on its way into the upper region of the outer storage container 2, as already described above.

The heat exchanger 50 is shown in detail in FIGS. 4 and 5. It has an essentially cylindrical casing 57 which is provided at the bottom with a rounded bottom 64 and at the top with a rounded cover 55. To vent the heat exchanger 50 is located approximately in the middle

Cover 55 a venting means 56. The secondary medium supply pipe 51 is fastened to an approximately centrally arranged pipe 62 by means of a flange 61. The tube 62 is located approximately along the longitudinal central axis of the cylindrical heat exchanger 50 and is open at its upper end. Radially offset to the outside is a tube 60 which is connected to the return line 52 for the secondary medium. The cold water line 53 merges in the heat exchanger 50 into a tube 68 which is connected to a plurality of tube coils 59 via a plurality of circular openings 63 and extends approximately radially to the longitudinal center axis. The individual coils spiral upward within the heat exchanger 50, and then in a corresponding tube

69 end, which is connected to the hot water line 54. The individual coils 59 are fastened to the wall of the inside of the jacket 57 by means of brackets 58.

The secondary medium fed into the heat exchanger by means of the line 51 rises in the central tube 62 and flows out of it in the direction of the arrows 66, 67 and flows around the coils 59 on its way down. It leaves the heat exchanger via the tube 60, which is connected to the return line 52, which leads the secondary medium back into the lower region of the outer storage container 2.

The heat exchanger 50 thus works on the countercurrent principle. The cold water supplied in its lower region via the line 53, which winds upwards from below in the coils 59, is first heated in the lower region of the heat exchanger 50 by the colder secondary medium which has already cooled in the upper region of the heat exchanger 50. Then it rises further up through the pipes 59 and is washed there with the even warmer secondary medium. It then leaves the heat exchanger 50 through the holes 65 in the tube 69 via the line 54.

The secondary medium which cools down when the water is heated flows from the outer storage container 2 through the pipe 60 into the line 52 and back into the outer storage container due to its density difference. The difference in density of the secondary medium means that a separate pump for operating the heat exchanger 50 can be dispensed with and gravity is sufficient for normal operation. In a particularly strong circulation of the secondary medium, however, a pump may be necessary.

Since the secondary medium, in particular if it is water, undergoes a change in volume during heating or cooling, an external pressure compensation container 70 is provided, as can be seen in FIG. 1, which is connected to the outer storage container 2 via a line 71. Thus, the necessary expansion of the water can be ensured in spite of the complete filling of the outer storage container 2. A thermometer 72 and a shut-off valve 73 are located on line 71 to monitor its temperature, in order to separate the pressure compensating container 70 from the heat store, for example for maintenance purposes. A manometer 74 is provided for monitoring the pressure prevailing on the line 71 or in the pressure compensating container 70 and, as a safety measure, an overpressure valve 76.

Since the temperature change causes the latent storage medium or the heat transfer oil to also experience volume changes, in the cover 4 of the latent heat store 100 there is provided a line 81 which communicates with the inner storage tank 1 via a connection 82 and which is connected to a

Expansion tank 80 is connected. Thus, in spite of the inner storage container 1 being completely filled with latent storage means or heat transfer oil, their volume changes can be allowed into the open without a breathing line. Thus, on the one hand, the capacity per volume of the inner storage container 1 or of the entire latent heat store 100 is increased, since in the

In contrast to the previously known solutions, there is no need for an expansion space present in the latent heat store. Furthermore, by dispensing with the breathing line to the outside, a closed system is achieved which prevents water from entering the latent storage medium or the storage container. Therefore, the latent storage medium does not change its properties due to water retention and there is also only a comparatively low level of corrosion. It is thus possible to use simple materials for the construction of the latent heat store 100. The Line 81 is provided with a shut-off valve 83, a manometer 84 for pressure monitoring and a safety valve 86.

The pressure gauge 84 for pressure monitoring has the advantage that the pressure, which correlates with the filling level of the inner storage container, makes it possible to monitor the state of charge or the degree of saturation of the latent storage medium or the heat transfer oil. At a high temperature, the latent storage medium melts and thereby reduces its volume, so that there is little oil in the expansion tank 80. If the temperature drops, part of the latent storage medium changes into the solid phase, as a result of which its volume increases, so that part of the heat transfer oil is displaced into the expansion tank 80. Thus, the pressure read on the manometer 84 also increases. Suitable means can be used to regulate the heat input into the latent heat store 100 via the manometer 84 or other means for determining the fill level, such as simple floats. This is of particular importance for the case of post-heating to be described, since there must not be a complete heating of the latent storage medium, so that capacities are always available for the preferably solar-powered heating.

At the lowest point of the bottom of the outer storage container 2 there is an outlet 8, so that the outer storage container can be emptied in a simple manner, for example for maintenance purposes. A comparable connection, which is led to the outside, can also be provided on the inner storage container 1.

If the secondary medium used in the outer storage container and also the storage medium flowing through the heat exchanger 5 are water, it is possible to connect the line 10 and the outer storage container 2, so that a particularly good use of energy in the secondary medium existing heat is reached. The latent heat accumulator shown as a whole in FIG. 2, designated 200, corresponds essentially to that known from FIG. 1, so that corresponding reference numerals increased by 100 are used for identical parts. The latent heat accumulator 200 differs essentially from the latent heat accumulator 100 only in that an external heating circuit 120 is connected to the outer storage container 2 for seasonal heating. This heating circuit 120 is necessary since the latent heat store according to the invention is preferably operated by means of solar systems. Depending on the season, however, an additional heating source is needed in northern latitudes when the sun's rays diminish. If, as is usually the case, electrical current is used for heating, the after-heating and heat storage must be carried out in the low tariff times if possible. So that heating can be carried out in the shortest possible time, it is advantageous to warm up the secondary medium in the outer storage container 2, which then releases the heat to the latent storage medium located therein via the inner storage container 1. This heat is released with a time delay. The direction of flow of the heat is therefore reversed in contrast to the case of consumption. Thanks to the rapid heating of the secondary medium, the low tariff time can be fully utilized and the short heating-up time means that very little electricity is used. Such an arrangement is also advantageous since the heat in the secondary medium is immediately available for consumption. Due to the external design, such a heating circuit can be used with all conceivable variants of the heating systems for the latent heat storage. The external heating circuit 120 comprises a line 121 which conducts the secondary medium from the outer storage container 2 to an electric heating element 123 and through an associated heating pot 124 for heating and then in turn leads back via a line 122 into the upper region of the outer storage container 2. A pump 126 and a valve 125 for flow regulation are provided in the heating circuit for circulation. In addition, a different number of shut-off valves or bypass lines can be provided in order to heating element or the heating pot without difficulty.

3 shows a latent heat storage battery designated as a whole as 300, which is composed of four latent heat stores according to the invention

400, 500, 600 and 700, which essentially correspond to those from FIGS. 1 and 2. In the exemplary embodiment shown, the storage battery 300 is used in particular for heating domestic hot water by means of regenerative energies. The domestic water heating is carried out via the secondary medium heated in the outer storage tanks 402, 502, 602 and 702 by means of the external heat exchanger known from FIG. 1, of which only one heat exchanger 450 on the first latent heat store 400 is shown in FIG. 3 for reasons of clarity. Corresponding heat exchangers are also arranged in the same way on the other latent heat stores. Likewise for reasons of clarity, the expansion tank 480 and the pressure expansion tank 470 are only shown on the first latent heat store 400. Corresponding devices are also available on the other heat stores. It would also be conceivable to connect the expansion tanks or pressure expansion tanks together to form a unit.

An external heating circuit 720, known from FIG. 2, is connected to the fourth latent heat store 700 and serves to heat the secondary medium in the outer storage container 702 if the regenerative energies are not sufficient. Such external heating circuits can also be attached to the other latent heat stores 400, 500 and 600, or it is possible, analogously to the expansion tanks, to carry out a common external heating device for all four latent heat stores.

In the exemplary embodiment shown, the latent heat stores 400,

500, 600 and 700 connected in series with regard to the heat supply of the heat exchangers 405, 505, 605 and 705. The heat originating from the regenerative energies is transferred via line 309 by means of the secondary medium first introduced into the first heat exchanger 405 in the first latent heat store 400 and emerges from the latter after a first release of heat via the line 310 and is then guided into the heat exchanger 505 of the latent heat store 500 in order to in turn further release its heat there. Subsequently, the heat exchanger 605 of the latent heat store 600 is supplied and finally the heat exchanger 705 of the latent heat store 700. In order to effectively utilize the remaining heat energy still present in the secondary medium, this is carried out after the last heat exchanger 705 in parallel via line 306 into all outer storage tanks 402, 502, 602 and 702 of the corresponding latent heat storage directed. In the corresponding outer storage containers, it displaces layers of colder secondary medium lying further down, which leaves the heat accumulator via the lines 307, which are likewise connected in parallel, and is fed back to the regenerative energy sources for heating via a collecting line 314 and a line 316.

Solar energy is preferably used as regenerative energy. This solar energy heats up a heat transfer medium in a collector K. Similar to the latent heat store, the collector system is provided with a pressure expansion tank 320 and a circulation pump 321. There are also a number of throttle valves, shut-off valves, pressure relief valves and control gauges or thermometers. The collector system is operated with a closed circuit and transfers its heat to the secondary medium in front of a heat exchanger 323. The heat transfer medium is therefore pumped in a circuit via lines 324 and 322.

The heated secondary medium flows from deiη collector K via a line 317 through a throttle valve and a check valve, after which it arrives in a pump which conveys it into a collecting line 315. On the one hand, the latent heat storage battery 300 is supplied by the collecting line 315 via the line 309. On the other hand, the secondary medium heated by solar energy, which is normally water, can be used without going through the storage battery or for heating the building. Normal wall heating H or floor heating FH can be used. For this purpose, several heating circuits provided with throttle valves, check valves, shut-off valves and pumps lead from the manifold 315 to the corresponding heaters H and FH. As is known, the temperature of the supply and return flow of a heating system differs only slightly, so that the return flow from the heating systems is partly fed directly back into this circuit. The remaining part is fed into the busbar 314 and again exposed to the regenerative heat sources.

In order to effectively utilize other available regenerative heat sources, particularly in times of low solar radiation, further heat sources such as heat pumps W or charcoal ovens 0 can be connected to the corresponding busbars 314 or 315 in order to supply the heating or the latent heat storage battery 300. The heat pump

W and the furnace O are also connected to the busbar 315 via throttle valves, check valves and pumps, so that the secondary medium in the corresponding heat source is heated as required by a control unit (not shown) and can be supplied to the system.

Furthermore, an external electrical heating unit E can be connected to the busbar 315 in order to regenerate the system, for example by means of low tariff current, in the same way as in the case of the external heating circuit 720, in the event of a failure of the regenerative heat sources or an insufficient supply by this heat to provide with heat.

It is obvious that a large number of operating modes are possible with the latent heat store according to the invention and its external additives using a wide variety of heat sources. For example, it would be conceivable not to operate the heating directly via the busbars 315 or 314, but rather to supply it with warm secondary medium via the latent heat storage battery 300. Furthermore, the use of the heated th secondary medium from the outer storage tanks for hot water supply is conceivable. The latent heat store according to the invention and its external additives can therefore be used in a wide variety of ways in a wide variety of systems and different situations and requirements.

Claims

1. Latent heat storage (100, 200, 400, 500, 600, 700) with a first storage container (1, 101, 401, 501, 601, 701), which is filled with a latent storage medium and preferably a heat transfer medium, and with a second storage container (2, 102, 402, 502, 602, 702), which is filled with a secondary medium, a heat exchanger (5, 105, 405, 505, 605, 705) being arranged in the first storage container for heating or cooling the latent storage medium, the first storage container is arranged within the second, outer storage container and the outside of the inner storage container is in connection with the secondary medium.

2. Latent heat store according to claim 1, characterized in that in the inner storage container (1, 101, 401, 501, 601, 701) arranged heat exchanger (5, 105, 405, 505, 605, 705) is flowed through by a secondary medium.

3. Latent heat accumulator according to claim 1 or 2, characterized in that the heat exchanger (5, 105, 405, 505, 605, 705) arranged in the inner storage container (1, 101, 401, 501, 601, 701) is a tubular heat exchanger.

4. Latent heat store according to claim 3, characterized in that the tubular heat exchanger comprises at least one approximately vertically arranged tube.

5. Latent heat store according to claim 3 or 4, characterized in that the tubes are arranged separately.

6. Latent heat store according to one of claims 2 to 5, characterized in that the tubes are arranged in a coil shape.

7. Latent heat store according to one of claims 2 to 6, characterized in that the tubes are provided with heat conducting plates.

8. Latent heat store according to one of the preceding claims, characterized in that outside the latent heat store (100,

400) a compensating tank (80, 480) communicating with the inner storage tank (1, 401) is arranged.

9. Latent heat store according to one of the preceding claims, characterized in that a, preferably on the expansion tank (80) arranged, level indicator (84) is provided for the inner storage tank ().

10. Latent heat store according to claim 9, characterized in that the level indicator (84) is provided for regulating the heat supply in the inner storage container (1).

11. Latent heat store according to one of the preceding claims, characterized in that means (120, 720) are provided with which the secondary medium present in the second, outer storage container (102, 702) can be heated.

12. Latent heat accumulator according to claim 11, characterized in that the means (120, 720) comprise a heating rod (123) which is preferably electrically operated and which is surrounded by the secondary medium, the heating rod (123) either inside or outside the second storage Cherbehälters is arranged.

13. Latent heat accumulator according to one of the preceding claims, characterized in that an external heat exchanger (50, 450) through which the secondary medium flows from the second, outer storage container (1, 401) is provided.

14. Latent heat store according to one of the preceding claims, characterized in that pressure compensation means are provided for the secondary media, which are preferably designed as a pressure compensation container (70, 470).

15. Latent heat storage device according to one of the preceding claims, characterized in that a plurality of latent heat storage devices (400, 500, 600, 700) are connected to form a storage battery (300).

16. Latent heat accumulator according to claim 15, characterized in that the first heat exchanger (5, 105, 405, 505, 605, 705)) and / or the second storage container (2, 102, 402, 502, 602, 702) are connected to one another in this way are that the secondary media the first heat exchanger (405, 505, 605, 705) and / or the second storage container (402, 502, 602, 702) in

Flow in a row and / or in parallel.

17. A method for latent heat storage and delivery, in which a secondary medium is heated or cooled by a latent heat store (100, 200, 400, 500, 600, 700), which is produced from a first storage container (1,

101, 401, 501, 601, 701), which is filled with a latent storage medium and preferably a heat transfer medium, and from a second storage medium. cherbehälter (2, 402, 502, 602, 702), which is filled with the secondary medium, wherein a heat exchanger arranged in the first storage container (5, 105, 405, 505, 605, 705) heats or cools the latent storage medium that first storage container is arranged within the second, outer storage container, so that the heat transfer between the

Latent storage medium and the secondary medium via the outside of the inner storage container.

18. The method according to claim 17, characterized in that the heat supply and / or removal by a suitable heating means (120, 720) or a consumer via the secondary medium.

19. The method according to claim 17 or 18, characterized in that the latent storage medium and possibly heat transfer oil in a with the inner storage container (1, 401) communicating expansion tank

(80, 480) can expand.

20. The method according to any one of claims 17 to 19, characterized in that the degree of saturation of the latent heat accumulator (100) on the level of the latent storage medium and possibly. Heat transfer oil in the

Expansion tank (80) is determined.

21. The method according to claim 20, characterized in that a control of the heat supply and / or the removal in or from the inner storage container (1) via the level indicator (84).

22. The method according to any one of the preceding claims, characterized in that heat is supplied and / or extracted via the secondary medium in the second, outer storage container.

23. Latent heat store (100) with a storage container (1), which is filled with a latent storage medium and preferably a heat transfer medium, wherein a heat exchanger (5), through which a heat transfer medium flows, is arranged in the storage container for heating or cooling the latent storage medium characterized in that an expansion tank (80) communicating with the storage tank (1) is provided.

24. Latent heat store according to claim 23, characterized in that a, preferably on the expansion tank (80) arranged level indicator (84) of the heat transfer medium is provided.

25. Latent heat accumulator according to claim 24, characterized in that the level indicator (84) is provided for regulating the heat supply in the inner storage container (1).

26. A method for latent heat storage and release, in which a secondary medium is heated or cooled by a latent heat store (100), which consists of a storage container (1) which is filled with a latent storage medium and preferably a heat transfer medium, one in the storage container arranged heat exchanger (5) heats or cools the latent storage medium, characterized in that the latent storage medium and possibly heat transfer oil can expand into a compensating container (80) communicating with the inner storage container (1).

27. The method according to claim 26, characterized in that the degree of saturation of the latent heat storage (100) on the level of the latent storage medium and possibly. Heat transfer oil in the expansion tank (80) is determined.

28. The method according to claim 27, characterized in that a regulation of the heat supply and / or the removal in or from the inner storage container (1) via the fill level indicator (84).

29. Latent heat store (100) with a storage container (1) which is filled with a latent storage medium and preferably a heat transfer medium and is in thermal contact with a secondary medium to be heated, wherein in the storage container (1) for heating or cooling the

Latent storage medium, a heat exchanger (5) is arranged, through which an externally heated or cooled heat transfer medium flows, characterized in that an external heat exchanger (50) through which the secondary medium flows is provided.

30. Latent heat store according to claim 29, characterized in that the storage container (1) is surrounded by a second, outer storage container (2) which is filled with secondary medium, the outside of the inner storage container (1) being in communication with the secondary medium and the external heat exchanger (50) flows through it.

31. Latent heat store according to claim 30, characterized in that the external heat exchanger (5) is arranged above the heat exchanger (50), an inlet (51) of the hot secondary medium approximately perpendicular to the upper region of the outer storage container (2) and an outlet ( 52) of the cooled secondary medium takes place approximately vertically in the lower region of the outer storage container (2).

32. latent heat accumulator according to claim 31, characterized in that the external heat exchanger (50) is operated by means of gravity.

33. latent heat accumulator according to one of claims 29 to 32, characterized in that the external heat exchanger (50) is a tubular heat exchanger.

34. Latent heat storage device according to claim 33, characterized in that the external heat exchanger (50) comprises at least one pipe coil (59) through which process water flows for heating.

35. latent heat storage device according to claim 34, characterized in that the coil (59) has a coil shape.