Plant comprising an absorption heat pump.

The present invention relates to a method for operating a system with at least one absorption heat pump, in which a working medium is expelled from an absorbent by supplying heat energy of relatively high temperature, the expelled working medium condenses, the condensed working medium relaxes, the relaxed, condensed working fluid evaporates with the supply of thermal energy at a relatively low temperature and the evaporated working fluid is finally absorbed again in the absorbent. Furthermore, the invention relates to systems that work according to such a method.

In order to make the most economical use of the available fossil and nuclear energy resources on earth, the heat pump has recently gained considerable importance in addition to the long-standing use for cooling, also for heating purposes. One problem that has not yet been completely solved is how to supply a heat pump with operating energy. Compressor heat pumps, which are driven by an electric motor, have the disadvantage that they put an additional load on the power grid and that this additional load at least partially coincides with the peak load times of the power grid. This applies to both heating and cooling (generally "air conditioning") of rooms. This disadvantage can be avoided by letting the heat pump run during times of low network load, especially at night, and storing the heat or cold generated in a heat or cold storage device, from which the heat or cold can then be removed if necessary. However, the heat emitted by a heat pump occurs at relatively low temperatures, so that voluminous, low-temperature heat stores are required in order to be able to store the required amount of heat, and the same applies essentially to the storage of cold.

Absorption heat pumps can be powered by an oil or gas burner, thereby avoiding some of the disadvantages of compressor heat pumps mentioned above. Absorption heat pumps that are supplied with operating energy by a gas or oil burner also have disadvantages:<ul id="ul0001" list-style="none"><li>An economic exploitation of the primary energy requires an adaptation of the cooling and / or heat output of the heat pump to the respective heat requirement, ie that the system must be controllable. Continuous control of oil burners has proven to be difficult, on the other hand, a two-point control is not as efficient as a continuous control and there is also a risk in times of relatively low heat demand, when the burner's switch-on times are relatively short and separated by longer breaks a condensation of combustion products in the chimney, so-called chimney sooting. The load on a gas pipeline network is also limited and in general a uniform load without high peaks is also desirable here during the main consumption times. In addition, when the oil or gas heating is switched off, considerable heat losses occur due to the inevitable convection through the chimney. Electric heating of absorption heat pumps has the same disadvantages in terms of network load as driving a compressor heat pump with an electric motor.</li></ul>

From US-PS 40 70 870 (Bahel et al) it is also known to generate hot water with solar energy, which is stored in a storage container and either for heating directly for heating purposes or when there is a need for cooling after additional heating in the condenser of a compressor heat pump for heating the expeller an absorption chiller is used. However, the thermal energy stored in the hot water cannot be used directly to operate the absorption chiller because of its low temperature level.

From US-PS 40 34 569 and this partially corresponding DE-OS 27 20 561 (Tschernev) a cooling device working on the principle of an absorption refrigerator is known, which works for example with the zeolite / water working medium system and is heated with solar energy. The cooling capacity is only available when the sun is shining, the heat released during condensation and absorption is not used and can practically not be used either because the temperature level during expulsion is low and should not exceed 100 ° C in practice. Since the expeller is heated by solar energy during the cooling process, the working fluid evaporated during the cooling process must be stored before it can be reabsorbed. So only work equipment and not operating or useful energy is stored. However, this publication does not state that zeolite has properties which make it suitable as an absorbent for a system with an absorption heat pump, in which both useful heat at a relatively high temperature level and useful cold can be generated in an advantageous manner and also energy can be stored effectively remove.

From DE-PS 596 308 (Normelli) a batchwise (discontinuously) working absorption refrigeration machine is known, in which the working fluid is expelled, condensed and stored when cheap energy, for example night-time electricity is available, and at a later time when '' Cold is needed, the stored working fluid for cooling is evaporated and absorbed again. The heat of condensation and absorption should also be used. Practical recycling has so far failed due to suitable absorption media / working fluid systems, and it was also not apparent from the Tschernev publications that the zeolite specified there for recycling low-temperature heat is also suitable for a device of the type mentioned above that works with completely different operating parameters .

Finally, multi-stage absorption heat pumps are known. The various stages mostly work continuously. The temperature of the operating heat supplied to the first stage was previously limited to values ​​below approximately 180 ° C, since work equipment systems for higher temperatures were previously not available.

The present invention is accordingly based on the object of specifying a system for generating heat and / or cold with at least one absorption heat pump which enables economical operation and the most favorable possible use of the available energy sources.

This object is achieved according to the invention in a system of the type specified at the outset by the characterizing features of patent claims 1 and 2.

In a system according to a first aspect of the invention, the heat or cold energy produced, which is available for heating or cooling purposes if required, is not stored, as is known, but operating thermal energy of a relatively high temperature is stored for the absorption heat pump, that is, heat energy that is increased by the heat pump when heating before being used for heating purposes or that is later used to generate cooling when cooling. The thermal energy for an expeller of the heat pump must of course be stored in a temperature range which is sufficient for the operation of the expeller of the absorption heat pump, for which an operating temperature range of the store from 200 ° C to about 100 ° C can be sufficient. However, there are particular advantages when using a so-called high-temperature heat accumulator, that is to say a heat accumulator whose maximum operating temperature (temperature of the storage medium at the end of charging) can be up to 800 ° C. and more and generally above 180 ° C., in particular above 200 ° C or 250 ° C will be.

An important aspect of the present invention is also to provide a sorption storage system that allows the storage of the operating heat for an absorption heat pump at sufficiently high temperatures and can also work as an absorption heat pump, which is operated in a new way with a special absorption medium / working fluid system Absorption heat pumps can also be used on their own, So without a downstream heat pump and because of it with operational heat energy (expulsion heat) it can be used with great advantage for heat and / or cold generation.

The use of a heat store for storing the operating energy for the absorption heat pump has very considerable advantages:<ul id="ul0002" list-style="none"><li>The heating device which supplies the heat to be stored in the heat store can be operated under optimal operating conditions. When using an electric heater to store heat in the heat accumulator, night-time electricity and excess current can be used in low load times. The heat from an engine, a turbine or an industrial process can also be stored in the heat accumulator. When the storage tank is heated with a furnace, it can be operated optimally and with relatively long heating periods, after which the storage tank can be thermally closed, so that no chimney losses occur.</li></ul>

A regulation on the heating side is not necessary, but you can regulate the absorption heat pump by taking the stored energy from the heat accumulator as required and in the amount required. "Operating energy" should therefore be understood to mean the relatively high temperature thermal energy used in the expeller to expel the working medium from the absorbent and not the relatively low temperature thermal energy supplied to the evaporator of the heat pump.

The preferred embodiments of the heat stores described below are harmless, environmentally friendly and work with non-toxic and non-corrosive substances.

Compared to the storage of heat and / or cold, which is emitted by a heat pump operated with night-time electricity, there is also the advantage that, despite the use of night-time electricity, the heat pump is used during the day, when the majority of the heat and / or cold is generally required will operate. During the day, the heat required for the evaporator is also generally available at a higher temperature level than at night, so that the useful heat is generated at a higher temperature level and / or the heat pump can be operated with a higher efficiency.

The term "absorption heat pump" is also intended to include absorption heat pumps, in which case evaporation and condensation of the working fluid correspond to desorption or absorption.

The concept of the invention is explained in more detail below on the basis of exemplary embodiments with reference to the drawing:<ul id="ul0003" list-style="none"><li>Show it:<ul id="ul0004" list-style="none"><li>Figure 1 is a schematic representation of a system containing an absorption heat pump according to an embodiment of the invention;</li><li>Figure 2 shows a modification of a part of the system according to Figure 1;</li><li>Figure 3 is a schematic representation of a preferred embodiment of a plant according to the invention;</li><li>FIG. 4 shows a schematic illustration of a divided heat store for a system of the type explained;</li><li>5 shows an advantageous embodiment of a heat exchanger for a system according to FIG. 3 or 4;</li><li>FIG. 6 shows a schematic illustration of a further embodiment of the invention, which contains two absorption heat pumps connected in series, both of which work discontinuously, and</li><li>Figure 7 is a structurally simpler preferred version of a system of the type shown in Fig. 6.</li></ul></li></ul>

The system shown in FIG. 1, which can be used for heating and / or cooling, contains an absorption heat pump, designated as a whole by 10, and a heating device, designated as a whole by 12, for an expeller 14 of the heat pump 10. The expeller &lt;14 contains an absorbent in a known manner which is capable of absorbing a working fluid which can be expelled from the absorbent by heating.

The expeller 14 has an outlet for gaseous working medium, which is connected via a line 16 to a condenser 18, which works as a heat exchanger and has a heat outlet 20. Useful heat is extracted from a heating system and waste heat is removed from a cooling system.

Liquefied working fluid is passed from the condenser 18 via a line 22, a throttle element 24 and a line 26 into an evaporator 28 which works as a heat exchanger and has a heat input 30 via which the thermal energy required for the evaporation of the liquefied and relaxed working medium can be supplied. When using the system for cooling, the heat input 30 absorbs the heat to be removed. The vaporized working fluid is fed via line 32 to an absorber 34, in which the working fluid vapor is absorbed by the absorbent. The heat of absorption released in this process occurs at a useful or waste heat outlet 36 of the absorber.

The absorbent loaded with working fluid is transported into the expeller 14 via a pump 38. The expeller 14 has a heat input part, for example in the form of a heating coil 40. The heat supplied expels the working medium from the absorption medium again, and the absorption medium essentially free of working medium is introduced into the absorber 34 via an absorption medium outlet line 42 and a throttle element 44 .

The _Absorption heat pump 10 operates continuously and contains further, conventional components which are not shown to simplify the drawing, for example heat exchangers between rich and poor absorption medium solution or between liquid and gaseous working medium. However, a discontinuously operating heat pump can also be used, as is explained, for example, with reference to FIG. 3 (212).

The heating device 12 for the absorber heat pump 10 advantageously contains a high-temperature heat accumulator 46. A high-temperature heat accumulator is to be understood as a heat accumulator that works with a maximum operating temperature of the storage medium that is above 250 ° C., preferably above 400 ° C. up to Is 800 ° C. Such high-temperature heat stores are known and in some cases technically mature. Known high-temperature heat stores are, for example, a) ceramic stores, for example Memories containing Mg0 ceramics; b) salt stores which use the heat of fusion of salts, eg LiF, c) cast iron stores and d) sorption stores. The construction of a suitable sorption storage device will be discussed below with reference to FIG. 3.

In the exemplary embodiment according to FIG. 1, the heat accumulator 46 is heated or “charged” by electrical heating elements. The actual storage medium is of course enclosed in a heat-insulating housing 50, which is only shown schematically.

A heat transfer circuit 52 can be used to transfer the stored heat from the heat store 46 into the expeller 14. This contains a coil 54 arranged in the heat accumulator, which is connected via a line 56 to the inlet of the coil 40 forming the heat input part in the expeller 14. The outlet of the pipe coil is connected via a line 58 to an intermediate store 60, from which a pipe 62, which contains a control valve 64, leads to the inlet of the pipe coil 54. If the heat transfer medium H₂0 is the line 56 carries steam, which condenses in the coil 40 with heat dissipation. The condensed water flows via the pipeline 58 into the intermediate storage 60. From there, the water is fed back into the coil 54 in which it evaporates again, as required, via the control valve 64 controlled by a suitable control device.

With the help of the control valve 64, the heat or cooling capacity of the absorption heat pump 10 can be continuously and easily controlled, so that good efficiency is ensured.

If a heat transfer medium is used in the heat transfer circuit 52 which remains liquid in the operating temperature range of the heat accumulator and the expeller, a circulation pump 66 is additionally provided in the heat transfer circuit 52. If the delivery rate (throughput) of the circulation pump can be controlled, the control valve 64 can be omitted.

When operating the system according to FIG. 1, the heat accumulator, which is preferably a high-temperature heat accumulator, such as a ceramic accumulator or cast iron accumulator with maximum operating temperatures of around 800 ° C., is charged by the electrical heating elements 48 during times of low current load on the network. The heat pump 10 is operated by removing thermal energy from the heat accumulator 46, the heat withdrawal and thus the heat emission and / or cooling output of the heat pump being independent of the charging of the heat accumulator 46 and can be controlled continuously by means of the control valve 64 or the pump 66 .

For emergencies, the expeller 14 can be provided with an auxiliary heating device 15, which enables the heat pump 10 to operate even when the heat store has not yet been charged or the thermal energy stored in it has been used up.

FIG. 2 shows a modified part of a heating device 112 for a heating system of the type shown in FIG. 1. The heating device 112 contains a heat accumulator 146, which is arranged in a combustion chamber 168. The combustion chamber 168 is provided with thermal insulation 150 and contains a burner 170 which is supplied with fuel (oil, gas) via a line 172. The heat accumulator 146 is preferably a high temperature heat accumulator, e.g. a ceramic or cast iron storage. It can also be heated by electrical heating elements 148.

The combustion chamber 168 is connected to a chimney 174, which can be closed by a gate valve 176 to avoid heat loss when the burner 170 is not in operation. in the chimney 174, a heat exchanger 178 is disposed for utilization of the residual heat of the combustion gases, which for example can be used for water heating. Instead of or in addition to a furnace for fluid fuels, heating by solid fuels (coal, wood, combustible waste) or hot exhaust gases can also be provided. Otherwise, the heating system can be designed as described with reference to FIG. 1.

Another type of storage which can be used with particular advantage is the so-called sorption storage, that is to say stores which work with desorption and sorption of a working medium from or in a sorbent, for example with the CaO / H system₂0. In the present case, however, sorption stores which contain zeolite as an absorbent in a very advantageous manner are preferred.

Fig. 3 shows a further advantageous embodiment of the system according to the invention, which works with a sorption memory. Components that correspond to components of the system according to FIGS. 1 and 2 are identified by reference numerals, the first number of which is a 2, while the last two numbers correspond to those of the corresponding components of the system according to FIGS. 1 and 2. The system according to FIG. 3 therefore only needs to be described to the extent that it differs from those according to FIG. 1 and 2 differentiates.

The heater 212 for the expeller 214 of the heat pump 210 in the system according to FIG. 3 is designed as a heat pump upstream of the actual heat pump 210 and contains a sorption heat accumulator 246, which preferably works with zeolite as the absorption medium and water as the working medium. However, other absorption / working medium systems can also be used, for example zeolite / CH₃OH zeolite / NH_3' CaO_2/H₂O or mixtures, which will be discussed further below. The heat accumulator 246 has a sealed housing 246a (which may consist of housing modules) in which the absorbent (not shown) is located. In the following it is assumed that the absorbent zeolite and the working medium H₂0 are. The housing is shown schematically as a box, in practice it will generally be constructed from several modules in a known manner.

The housing 246a is connected to a working fluid steam outlet line 382, ​​which contains a shut-off valve 382a and leads to a heating coil 340 in the expeller 214 of the absorption heat pump 210. The output of the heating coil 340 is connected to a working medium storage vessel 384, which in the working medium H₂0 So it contains liquid water. The storage vessel 384 has an outlet line 386, which is connected via an optional liquid / gas heat exchanger 387, which is advantageous in the case of high working fluid vapor density in the evaporator 394, to a throttle element 388, which consists of a shut-off and control valve and with its low pressure side an evaporator 394 and the gas side of the heat exchanger 387 is connected to a working medium inlet line 390 of the sorption store 246, which contains a shut-off valve 390a. A heat exchanger 392 can advantageously be provided between the outlet side of the heating coil 340 and the inlet of the storage vessel 384, from which useful heat can be removed.

In the heat accumulator 246, a coil 254 is also arranged, which serves to dissipate the thermal energy, which is stored in the heat accumulator 246 as specific heat and which is released as sorption heat when the working medium is introduced. The coil 254 is connected to a heat transfer circuit 252, which, for example can work with water as a heat carrier and contains an outlet line connected to the outlet side of the pipe coil 254, which leads to a second heating coil 240 arranged in the expeller 214. The outlet side of the heating coil 240 is connected via an outlet line 258, which contains a heat exchanger 304, to the inlet of a heat transfer medium reservoir 260, the outlet of which is via a control valve 264 (or a controllable pump / corresponding to the pump 66 in FIG. 1) is connected to the inlet end of coil 254.

3 operates as follows:<ul id="ul0005" list-style="none"><li>Thermal energy is stored in the heat accumulator 246 by means of the electrical heating device 248 and / or the burner 270 and / or by supplying hot air, hot exhaust gases and the like. The working fluid is expelled from the absorption medium in the heat accumulator 246 and desorption heat and specific heat are stored in the absorption medium. During the expulsion, valve 382a is open and valve 390a is closed. The working fluid vapor flows through the heating coil 340, where it condenses and gives off heat to the expeller 214 of the absorption heat pump 210. The liquefied working fluid (water) is stored in the storage vessel 384. Control valve 388 will generally be closed while heat accumulator 246 is charging. If no operating heat is required for the heat pump 210, heat can be extracted from the working fluid by the heat exchanger 392, for example for heating or water heating.</li></ul>

If heat is later required for the expeller 214 of the heat pump 210 and / or cooling at the inlet of the evaporator 394, working fluid can flow into the sorption heat accumulator 246 in a controlled manner through the throttle element 388 designed as a shut-off and control valve. The valve 382a is now closed and the valve 390a is open. The working medium is then absorbed by the absorption medium, whereby sorption heat is released, which is transported through the heat transfer circuit 252 to the heating coil 240 in the expeller 214 and now supplies the heat pump 210 with operating energy.

In the operating mode described above, the heating coils 340 and 240 therefore both deliver thermal energy to the expeller 214 at different times.

If the heat accumulator 246 is discharged to such an extent that the temperature of the heat carrier in the heat carrier circuit 252 is no longer sufficient to heat the expeller 214, the residual heat can be transferred from the heat accumulator_-. the heat exchanger 304 are removed.

It has already been mentioned that the heat input side of evaporator 394 can be used for cooling purposes. However, if heat is available at a higher level, e.g. exhaust air heat or the like, the heat input side of the evaporator 394 can be subjected to a correspondingly high temperature, which has the advantage that the temperature level in the heat accumulator 246 shifts to higher values ​​and in the heat transfer medium circuit 252 correspondingly higher temperatures are available.

As already mentioned above, the heating device 212 can also be operated as a simple (without heat increase) sorption heat accumulator. This has the advantage that a larger part of the useful heat is available as useful heat during the later sorption operation. In this case the heating coil 340 is then short-circuited by 341 and the expulsion is carried out in the expeller 246 at such low pressures that the condensation in 392 takes place at ambient temperature. The sorption process proceeds as described and the useful heat generated is removed via the heat transfer circuit 252.

The system according to FIG. 3 can be modified in that the heating coil 240 is short-circuited by a three-way valve 305 or omitted at all and the heat carrier outlet line 256 is connected directly to the heat exchanger 304. In this case, the heat is then removed as useful heat when the heat accumulator 246 is discharged via the heat exchanger 304 and is used, for example, for preparing dishes, for washing, rinsing, heating and the like.

If the heat storage 246 stored heat is only to be used for space heating, the heat transfer circuit 252 can be replaced by a blower or the like which blows air in a controlled manner through corresponding air channels in the storage 246.

Another variant, which also has its special advantages, is to omit the heating coil 340 or to short-circuit it by means of a three-way valve 341. The condensation heat that is released when the heat accumulator 246 is loaded and when the storage device 384 is filled is then removed in this case exclusively via the heat exchanger 392 and used as useful heat.

Under certain conditions, for example if heat at a relatively high temperature is required or the efficiency of the heat pump 210 is poor because of the very low outside temperature for heating purposes, all the useful heat can be removed via the heat exchangers 304 and 392 at a relatively high temperature.

In principle, in the heating system according to FIG. 3, the heat exchanger 387 and the evaporator 394 can be omitted. By means of the evaporator 394, to which inferior low-temperature heat can be supplied, the working medium circuit also works in a very advantageous manner as a heat pump, and the heat that can be removed by the heat transfer circuit 252 is increased by the amount of heat supplied via the evaporator 394. In the case of cooling, the cooling capacity is additionally increased by the heat absorbed by the evaporator 394. In this case, the heat accumulator 246 also works as an expeller and as an absorber of a discontinuously operated heat pump, which is to be understood as operation with a time shift or time interval between the expulsion process and the absorption process.

In this connection, it should be noted that the construction of the heat pump 10 (Fig. 1) and 210 (Fig. 3) is not limited to a specific type. You can use both continuously working types (as described) as well as types that work discontinuously in the sense defined above for these heat pumps. In a discontinuously operating absorption heat pump, it is known that various components, which have been mentioned individually above, can be functionally combined, for example expeller and absorber and / or evaporator and condenser, which will be explained further below with reference to FIGS. 6 and 7.

It has already been mentioned above that the heating device 212, which supplies the expeller 214 with thermal energy, operates as a discontinuously operated heat pump with respect to the working medium circuit 382-392-384-388-394-390 containing the sorption storage 246. If one uses in the heat accumulator 246, alternatively operated as an expeller and absorber, with zeolite as the absorbent, the result is a heat pump system which can also be operated on its own, that is also without a downstream heat pump 210, since it is capable is to deliver useful heat at temperatures in the order of 100 ° C and above. This is not possible with the known absorption media / working fluid systems. With the NH system_3/H₂0 the useful heat can be generated at a maximum of 60 ° C and then the pressure of the working fluid when it is driven out is already 30 bar. The LiBr / H system₂0 Although it permits higher useful heat temperatures, the corrosion problems then become considerable and, due to the increasing decomposition of the lithium bromide, a limit is reached even at expeller temperatures of approximately 150 ° C. By contrast, with the heat pump containing zeolite as the absorbent, heat of a higher temperature, for example in the temperature range from 150 to 300 ° C. and above, can be used to generate a larger amount of heat at temperatures around 100 ° C. The increase in heat is based on the "pumping up" of the inferior low-temperature heat supplied to the evaporator 394, which can be taken, for example, from the ambient air, the groundwater, an "energy roof" or the like.

If the system 212 is used without a downstream heat pump 210, the heating coils 240 and 340 are omitted and the useful heat is taken from the condenser 392 and the heat carrier circuit 252. The system 212 can also take the place of the heat pump 10 in FIG. 1.

With the installation according to FIG. 3 containing the heating device 212 and the downstream heat pump 210, very high efficiencies can be achieved. Both for the heating device 212 operating as a heat pump and for the downstream heat pump 210, the theoretical performance figure (high-temperature heat used and low-temperature useful heat gained) is 2.0 in each case. In practice, a power factor of 1.4 can be expected for the heating device and a power factor of 1.5 for the heat pump 210, which results in an overall efficiency of 2.1. If one calculates with the burner 270 an efficiency of 0.8, which can be achieved with modern oil or gas burners, then one obtains a total power factor of 1.7 for the primary energy used. The performance figure of the best known absorption heat pump systems is only about 1.2.

If the zeolite with H₂0 is operated as a working medium, which is generally preferable, there is a risk that the working medium (water) freezes in the evaporator 394 at low outside temperatures. You can prevent this by taking the following measures:<ul id="ul0006" list-style="none"><li>First, you can add an anti-freeze, such as ethylene glycol, to the water in evaporator 394. Secondly, the evaporator 394 can be bridged by a valve, so that when the valve 386a is open, liquid water through the line 390 into the reservoir₂₄₆ is introduced.</li></ul>

With regard to the operation of the system shown in FIG. 3, the following should also be noted:<ul id="ul0007" list-style="none"><li>a) Heat can be taken from the condenser 218 and / or from the absorber 234 and fed to the evaporator 394. In this operating variant, the heat transfer medium from 218a or 236 is first flowed through 394a before it is fed to a heat consumer or cooling tower K. A high temperature is achieved in the evaporator 394. For this purpose, the heat exchanger 394a is connected to the heat exchangers 236 and 218a via the lines X, Y. The theoretical performance figure of the entire system is then still 3.0, the practical performance figure is about 1.7 and for the utilization of the primary energy, including the burner efficiency, there is still a performance figure of 1.36.</li><li>b) The efficiency of the heat pump 210 can be improved by using the evaporator 394 to<ul id="ul0008" list-style="none"><li>1. continue to cool the liquid working fluid upstream of the throttle valve 224,</li><li>2nd to cool the heat transfer medium that flows through 236 before entering the absorber 234 and / or to cool the heat transfer medium that flows through 218 a before entering the condenser 218. In this case, the heat transfer medium flows in 218a or 236 first through the heat consumer or cooling tower K and then through the evaporator 394. The resultant lowering of the inlet temperature into the condenser 218 or Absorber 234 entering the heat carrier increases the exit width of the absorbent in the heat pump 210.</li></ul></li><li>c) A further operating variant for heating consists in discharging the sorption storage 246 with ambient heat supplied to the evaporator 394, the temperature of which may be, for example, 5 ° C., until the temperature of the heating coil 240 for expelling the working medium in the expeller 214 no longer exists sufficient; in this mode, as mentioned, the theoretical efficiency of system 210-212 is 4.0. Then the heat transfer circuit, which supplies the evaporator 394 with input heat, is switched over to the condenser 218 and / or the absorber 234 as the heat source, with a theoretical efficiency of 3.0 still being obtained. As a result of this measure, the vapor pressure of the working medium in the sorption store 246 rises and thus the temperature, the store can be further discharged in this way via the heat transfer circuit 252, so that the expeller 214 again receives operating energy of sufficiently high temperature via the heating coil 240.</li></ul>

The above explanations relate mainly to the heating mode. The following can be done in cooling mode:<ul id="ul0009" list-style="none"><li>The memory 246 is loaded with energy, with working medium being expelled and operating energy being supplied to the expeller 214 of the heat pump 210 via the heating coil 340, so that cooling capacity is available on the evaporator 230 and is supplied to a cooling consumer W. (W can mean the surroundings in other operating modes).</li></ul>

When the storage unit is discharged, cooling capacity is available on both evaporator 230 and evaporator 394. The theoretical efficiency of the combination 210-212 is 3, ie one unit of input heat at the sorption store 246, which works alternately as expeller and absorber, theoretically gives three units of cooling. If the heat pump 210 has a cooling efficiency of 0.7, which is a real value for a lithium bromide-water machine, and the practical efficiency of the heater 212 converting the input heat into the operating heat for the heat pump 210 is 1.4, then one has a total cooling efficiency of 0.7. 1.4 + 0.4 = 1.38. The summand 0.4 is the contribution of the evaporator 394.

The system described above thus has an efficiency even when heated with electricity, which is approximately equal to that when supplying a compressor cooling machine (η ≅ 2.1) with electricity from a pump^pstorage power plant (n ≅0.65). In addition, there are the typical advantages for decentralized plants and a relief of the power grid and the electricity generation capacity during peak load times. If with increasing discharge of the Sor^ption memory 246, the temperature in the expeller 214 is no longer sufficient to operate the heat pump 210, the cooling capacity can only be generated at the evaporator 394. The heat pump 210 is then switched off and the cooling fluid, which would otherwise be caused by the condenser 218 and / or the Absorber 234 flows, is now passed through the heat exchanger 304, which means that the accumulator 246 can be completely discharged and additional cooling power can be generated in 394.

From a technical point of view, it can be advantageous not to use the cooling capacity of the evaporator 394 directly, but to improve the efficiency of the heat pumps 210 and 212, which are now working as refrigerators, by using the measures described above in connection with the heating operation as operating variant a) , b) and c) have been discussed.

The following are some examples of the operating parameters of the sorption memory 246; in all cases, the maximum temperature during expulsion must be selected so that the stability limit of the absorbent / working agent system used, for example the zeolite, is not exceeded.

EXAMPLE I: Zeolite Absorbent; Work equipment H₂0 The degree of saturation ξ of the absorbent is said to be the ratio of the weight of the sorbed H₂0 defined for the weight of the zeolite in the desorbed state.

A absorber operating cycle of the sorption memory 246:

<tables id="tabl0001" num="0001"><img file="EP0026257A2_D0001.tif" /></tables>This operating mode a) is suitable for a low inlet temperature at the evaporator 394, for example for ice production or cooling.

Operating modes b) and c) are suitable - for generating a high output temperature in the heat transfer circuit 252.

B Driver operation cycle of the sorption memory 246

<tables id="tabl0002" num="0002"><img file="EP0026257A2_D0002.tif" /></tables>

Some zeolites may not be driven out to ausg = 0.05, otherwise the stability limit will be exceeded.

EXAMPLE II

<tables id="tabl0003" num="0003"><img file="EP0026257A2_D0003.tif" /></tables>

A absorber operating cycle:

<tables id="tabl0004" num="0004"><img file="EP0026257A2_D0004.tif" /></tables>

B Driver operating cycle

<tables id="tabl0005" num="0005"><img file="EP0026257A2_D0005.tif" /></tables>

The fact that the Ca0 in whole or in part by Mg_xApprox_1-xO replaced with x to approx. 0.3 and / or zeolite added, the expeller temperature can be reduced with the same expeller pressure and the same condenser temperature. x can also have larger values, e.g. 0.5.

It may be advisable to divide the heat store in order to adapt its heat capacity to seasonal fluctuations in the heat demand, for example. In summer, for example, it would take a relatively long time for a heat accumulator with a heat capacity designed for winter operation to be completely discharged, and the accumulator would then work in an unfavorable, low temperature range for a relatively long time.

A subdivision of the storage also enables quasi-continuous operation by phase-shifted working of the storage parts, and the efficiency of the system can be improved by internal heat exchange between the storage parts.

FIG. 4 shows, for example, a sorption storage device of the type explained with reference to FIG. 3, which is divided into two halves 246a and 246b, and in a system according to FIG. 3, 6 or 7 and also the system according to FIG. Fig. 1, if the heat pump 10 is a batch heat pump can be used. There is thermal insulation 250 between the two storage halves. A separate electrical heating device 248a or 248b and / or a separate burner 270a or 270b is provided. In each storage half there is a coil 254a or 254b, which can be optionally switched into the heat transfer circuit 252 (FIG. 3) via three-way valves 400.

Each storage half also has a working fluid outlet line 382a or 382b, which can optionally be connected to line 382 (FIG. 3) via a three-way valve 402. In a corresponding manner, each storage half has a working fluid inlet line 390a or 390b, which can optionally be connected to line 390 via a three-way valve 404.

A heating system with a divided heat store, as shown in Fig. 4, can be operated advantageously in different ways:<ul id="ul0010" list-style="none"><li>In times of low heat demand, e.g. in summer, the heating system can be operated with only one half of the storage tank. So only one half, for example half 246a, is fully charged and discharged. The memory losses are then less than when using the entire memory.</li></ul>

In the case of a sorption store, one can also operate the two halves alternately as expeller and absorber, so that quasi-continuous operation of the heat pump part of the heating device 212 (FIG. 3) is then possible. It is then possible to continuously extract heat from the heating coils 240 and 340 and from the heat exchangers 304 and 392 and to continuously generate cold on the evaporator 394.

Another advantage of subdividing a sorption heat store is that the thermal energy generated in the expeller phase can be "stored" by introducing expelled working fluid into the storage part working in the absorber mode.

Some of the advantages which have been explained above in connection with the division of a sorption store also result from the division of other storage types, such as ceramic, cast iron and chemical stores.

With alternating operation of the two storage halves, the waste heat obtained from the flue gases can be fed from the heat exchanger 278 (FIG. 4) to the evaporator 394 (FIG. 3). This then increases the temperature level during the absorption phase, since a higher working fluid vapor pressure is established.

A similar temperature increase also results if the evaporator 394 is supplied with high temperature thermal energy from kitchen exhaust air or the like.

FIG. 5 shows a heat exchanger 504 which can be used with particular advantage instead of the heat exchanger 304 (FIG. 3). The temperature of the heat carrier in the heat carrier circuit 252 (FIG. 3) changes relatively strongly during the absorption operating cycle of the absorption heat accumulator 246. The heat exchanger 504 is a hot water boiler, to which cold water can be supplied at the bottom via a line 506 and hot water can be taken off via a line 508. The line 508 is connected via a three-way valve 510 to a lower and an upper water withdrawal connection 512 or 514 of the hot water boiler.

The hot water boiler contains, for example, three heating coils 516, 518 and 520. The input side of the heating coil 516 is connected to the heat transfer circuit 252 via an input line 307 (see also FIG. 3). The inlet sides of the coil 518 and 520 can be closed by valves 522 or 524 optionally connected to the input line 307. The output side of the heating coil 516 is connected directly to the input of the heat transfer medium 560, while the output sides of the heating coil 518 and 520 are each connected to the inlet of the heat transfer medium 560 via a check valve 526 and 528, respectively. If at the beginning of the absorption cycle the temperature of the heat carrier in the heat carrier circuit 252 is still relatively high, the heat carrier is only passed through the heating coil 516, the valves 522 and 524 are closed. As the temperature drops, the valve 522 and finally the valve 524 are then opened and the temperature of the heat carrier is thus adapted to the temperature stratification of the water column in the water heater 504.

FIG. 6 shows an embodiment of the invention, which contains a heating device 212 of the type described with reference to FIG. 3, followed by a heat pump 610, which operates discontinuously in the sense defined above. The heat pump 610 contains an expeller 614 which is heated by the heating device 212 and which alternately works as expeller and absorber. The working medium expelled during the expulsion phase flows through a working medium output line 682 containing a valve 682a to a condenser 618, from which useful or waste heat is extracted via a heat exchanger coil 618a, and is condensed there. The condensed, liquid working fluid flows into a storage vessel 600 (which corresponds functionally to the storage vessel 384). From the storage vessel 600, the liquid working medium is fed through a control valve 624, which acts as a relaxation device, to an evaporator 630, which contains a heat exchanger coil 630a and absorbs heat, so that a device connected to the heat exchanger coil 630a can be cooled. The evaporated working fluid then flows back from the evaporator 630 via a working fluid inlet line 690, which contains a valve 690a, in particular a non-return valve, to the expeller absorber 614. The expeller absorber 614 further contains a device for removing the work fluid from the absorption absorbing heat. This device is shown in Fig. 6 Shown as a heat transfer circuit 636, which is a heat exchanger coil 654, which is used to remove the sorption heat and is arranged in the expeller absorber 614, a heat exchanger 604 (for example a space heater or the like) for utilizing or removing the sorption heat removed, a heat transfer reservoir or compensating valve 660 664 and, if necessary, a circulation pump 666. The expeller absorber 614 can, however, also be designed such that the sorption heat released during absorption can be removed directly from it, for example by blowing air through a tube system passing through it.

The expeller absorber 614 operates as an expeller during a first period (expulsion phase). The valve 682a is open and the valve 690a is closed. The gaseous working medium expelled from the absorbent by the supply of heat from the heating device 212 flows through the line 682 into the condenser 618, where it condenses with the release of useful heat and the condensed working medium is then collected in the storage vessel 600. Control valve 624 and valve 690a will generally be closed during this phase. The heat transfer circuit 636 is out of operation during this expulsion phase.

Then, or at any later point in time, the expeller absorber is switched to absorber operation. The valve 682a is closed, the valve 690a is opened and, by means of the control valve 624, liquid working fluid is fed in a controlled manner from the storage vessel 600 into the evaporator 630 in accordance with the heating and / or cooling requirement. The evaporating working fluid absorbs heat so that a device connected to the heat exchanger coil 630a can be cooled. At the same time, absorption heat is released in the expeller absorber 614, which heat is removed via the heat transfer circuit 636 and can be used, for example, for hot water preparation or the surroundings can be dissipated.

For example, the following absorbent-working agent system are suitable for FIG. 6:<tables id="tabl0006" num="0006"><img file="EP0026257A2_D0006.tif" /></tables>

The heat transfer medium in the circuit 252 can be, for example, water (steam) or oil.

It may also be advantageous not to remove the heat of vaporization for the evaporator 394 from the environment or from a system to be cooled, but from the condenser 618 and / or the heat exchanger 604.

FIG. 7 shows a schematic representation of a system according to the invention of the type explained with reference to FIG. 6, which, however, is further simplified by combining certain structural units and interconnecting the working fluid circuits of the heat pump serving as a heating device and the downstream heat pump. In this case, the working fluid in the two heat pump circuits and the heat transfer medium in the heat transfer circuit must be made of the same substance, eg H₂0 consist.

The system according to FIG. 7 contains a sorption memory 246, which operates alternately as an expeller and absorber, which corresponds to that of the system according to FIG. 3.

The system also contains an absorber expeller 714, which fulfills the function of the expeller absorber 614 and contains a heating coil 754, which fulfills the functions of the heating and heat exchanger coils 240, 340 and 654 of the system according to FIG. 6. An evaporator 794, which fulfills the function of evaporators 394 and 630 (FIG. 6), works together with expeller-absorber heat stores 246 and 714. It is fed by a storage vessel 760, which fulfills the functions of the storage vessels 600 and 384 in FIG. 6.

A condenser 718 cooperates with the expeller absorber 714 and fulfills the functions of the heat exchanger 604 and the condenser 618. The working medium condensed in it flows into a storage vessel 760, which fulfills the functions of the storage vessels 600 and 660 and part of the function of the storage vessel 384. The functions of heat exchanger coils 240, 340 and 654 are performed by a single heat exchanger coil 754.

A heat exchanger 792 is also provided, which fulfills the functions of the heat exchangers 392 and 304.

The above-mentioned units are connected to one another by lines which contain valves 701 to 713 and 717 and are connected in the manner shown in FIG. 7. 7 is controlled according to the following table, in which an "o" means the operating state "open" and "-" the operating state "closed" of the valve in question.<tables id="tabl0007" num="0007"><img file="EP0026257A2_D0007.tif" /></tables>

The valves 715 and 716 are used to clean the storage containers 760 and 784. The removal of working fluid from the storage container 760 for sorption in both 714 and 246 results in a better efficiency in the evaporator 794, because the average temperature level in 760 is lower than in 784.

6 and 7, subdivided heat stores 246 can also be used, as was explained above with reference to FIG. 4.

The heat pumps described, which work with zeolite as an absorption medium, can be used with great advantage to utilize the waste heat of a gasoline or diesel engine, particularly in quasi-continuous operation with a double accumulator according to FIG. 4, either alone or with a downstream heat pump 210. Here, the heat of the exhaust gases is used for expulsion and the cooling water or cooling air heat (cooling fluid heat) for heating the evaporator (for example 394 in FIG. 3). Useful heat is obtained, the temperature of which is above the cooling fluid temperature, so that the entire waste heat of the engine is available at a higher temperature level. This heat can be used either directly for heating or via an absorption heat pump (eg 210 in Fig. 3) for heating and / or cooling, especially if the engine in turn drives a compressor heat pump.

The term "storage with a temperature sufficient for expulsion" is intended to mean in general that the stored thermal energy is available at a sufficiently high temperature when it is removed from the heat store.