Patent Publication Number: US-2019186792-A1

Title: Assembly, in particular refrigeration machine or heat pump

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to International Application PCT/EP2017/000988 filed on Aug. 16, 2017, and to German Application DE 10 2016 215 374.9 filed on Aug. 17, 2016, the contents of each are hereby incorporated by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The invention relates to an assembly, in particular to a refrigeration machine or heat pump, and to a method for operating this assembly. 
     Thermally driven sorption refrigeration systems possess a high energy-saving potential since as drive energy cost-effective waste or excess heat is utilised and in this way expensive mechanical drive energy can be saved. In stationary applications, the electrical networks can be relieved particularly in warm time and climate zones with high refrigeration requirement. During the cold time of the year, the systems can also be utilised as heat pumps which by means of burner heat raise additional environmental heat to a temperature level that is adequate for heating purposes. 
     BACKGROUND 
     Before this background devices are known from the prior art in the case of which porous solids are employed which react with a working medium while converting heat and which do not have any moving wear parts that are thus susceptible to faults in the working medium section. 
     Adsorption heat pumps or adsorption refrigeration systems realised with the help of such thermochemical reactors however have the disadvantage compared with continuously operating absorption systems that the periodical temperature changes with cycled thermal masses result in efficiency losses which diminish the performance density or performance efficiency achieved by the adsorption heat pump or adsorption refrigeration system. 
     In this connection, DE 10 2006 043 715 A1 discloses an adsorption heat pump, in which a layered heat store is employed. 
     Said layered heat store allows storage and reuse of sensible and latent heat that is offset in time during the adsorption cycle. The same allows a time-offset storage and reuse of sensible and latent heat during the adsorption cycle. Because of their large volume, such layered heat stores cannot be employed everywhere. 
     SUMMARY 
     It is an object of the present invention to show new ways in the development of sorption heat pumps or sorption refrigeration machines in particular with improved efficiency. 
     This object is solved through the subject of the independent patent claims. Preferred embodiments are subject of the dependent patent claims. 
     Accordingly, the basic idea of the invention is to equip an assembly with an adsorption heat pump or an adsorption refrigeration machine with a sorption module—here uniformly referred to as “thermochemical reactor”—with a temporary heat store, which comprises two sub-stores for receiving a heat medium fluid with two different temperature levels. This temporary heat store serves for temporarily storing heat contained in the heat transfer fluid during the thermal cycling of the thermochemical reactor and during the switching of the thermochemical reactor between two different temperature levels connected with this. Generalising, the term “thermochemical reactor” is to mean a vessel with at least one working medium and an integrated heat transfer structure, with which at least dependent on a temperature peripheral condition and subject to heat removal or supply an exothermic or endothermic reaction or phase conversion can be caused to take place. Such more specific embodiments, components or subcomponents are also known under the terms “sorber”, “sorption reactor”, “thermochemical store” or “phase changer”. 
     The temporary heat store used here that is substantial for the invention allows the temporarily storage of the heat transfer fluid with the temperature level of a heat sync of the assembly in the second sub-store of the temporary heat store. 
     An increase in volume of the first sub-store in the case of the temporary heat store that is substantial for the invention is accompanied by a decrease in volume of the second sub-store and vice versa. Since the two volume-variable sub-stores have the same total volume, introducing the heat transfer fluid with the temperature level of the heat source into the first part space facilitates a discharging of the heat transfer fluid with the second temperature level from the second sub-store and vice versa. In this way, undesirable energy losses of the thermochemical reactor during the thermal cycling, i.e. during the switching between the two temperature levels of heat source and heat sync can be minimised. This results in an improved efficiency of the assembly according to the invention compared with conventional assemblies. 
     An assembly according to the invention, in particular a refrigeration machine or a heat pump, comprises a first heat reservoir, which functions as heat source, and a second heat reservoir, which functions as heat sync. The assembly, furthermore, comprises a thermochemical reactor that can be or is thermally and fluidically connected to the heat reservoir. Preferably, the thermochemical reactor is an adsorption refrigeration machine or an adsorption heat pump or is a substantial functional component thereof. 
     Furthermore, the assembly comprises a heat transfer fluid circuit in which a heat transfer fluid for transporting heat between the two heat reservoirs and the thermochemical reactor is arranged. In the heat transfer fluid circuit a temporary heat store for temporarily storing the heat transfer fluid is provided. According to the invention, the temporary heat store comprises a first sub-store with a variable storage volume. Furthermore, the temporary heat store, thermally and fluidically separated from the first sub-store, comprises a second sub-store with variable storage volume. 
     A delivery device of the assembly according to the invention that is present in the heat transfer fluid circuit serves for driving the heat transfer fluid in the heat transfer fluid circuit. Furthermore, the assembly comprises a valve system that is present in the heat transfer fluid circuit which comprises four adjustable valve devices. 
     By means of a first valve device, the fluid inlet of the thermochemical reactor can be optionally connected to the fluid outlet of the first or second heat reservoir. By means of a second valve device, a fluid outlet of the thermochemical reactor can be optionally connected to the fluid inlet of the first or second heat reservoir. By means of a third valve device, the first sub-store can be optionally connected via the first heat reservoir or directly to the first valve device. By means of a fourth valve device, the second sub-store can be optionally connected via the first heat reservoir or directly to the first valve device. At least one part of these four valve devices are controllable and adjustable by means of a control/regulating device. 
     By means of these four adjustable valve devices, the heat transport between the two heat reservoirs, the thermochemical reactor and the temporary heat store is controllable through the heat transfer fluid. 
     In a preferred embodiment, the temporary heat store is designed for the simultaneous receiving and output of a first and of a second fluid mass of the heat transfer fluid, wherein the two fluid masses have different temperature levels. At the same time, this allows temporarily storing fluid mass in the temporary heat store in the temperature range of the heat source and fluid mass in the temperature range of the heat sync in a temperature-layered form. 
     Particularly preferably, the first sub-store of the temporary heat store is fluidically connected to the first heat reservoir and the second sub-store of the temporary heat store is fluidically connected to the second heat reservoir. This measure allows a simple feeding of stored hot heat transfer fluid from the temporary heat store into the first heat reservoir of the heat source being at a high temperature level. Likewise, this measure allows a simple feeding of stored cooler heat transfer fluid from the temporary heat store into the second heat reservoir of the heat sync being at a lower temperature level. 
     According to a particularly preferred embodiment, the temporary heat store is realised as a vessel. In this version, the vessel comprises a housing in the interior of which a separating element is moveably arranged, which subdivides the interior into a volume-variable first sub-store and a second sub-store that is thermally insulated from the first sub-store and likewise volume-variable. In the housing, a first passage for introducing and discharging the heat transfer fluid into or from the first sub-store is provided. 
     Furthermore, a second passage for introducing and discharging the heat transfer fluid into or from the second sub-store is provided in the housing. 
     In an advantageous further development, the housing is designed elongated. Here, the first passage is arranged at a first longitudinal end and the second passage at a second longitudinal end located opposite the first longitudinal end. The large length/cross-section ratio accompanying an elongated design of the housing serves for the purpose that a temperature layering of the inflowing or out flowing fluid mass is largely retained and is not significantly intermixed during the required storage time. 
     Practically, the housing can be designed as a tubular body which extends along an axial direction in a substantially straight line. In this version, the separating element for forming the two volume-variable sub-stores moveably lies along the axial direction against the inside of a circumferential wall of the tubular body. Such a design is technically easily producible and thus involves low manufacturing costs. 
     In a further advantageous further development, a first sensor element is provided at the first passage, by means of which it can be determined if the separating element is located in a first end position, in which the separating element is located at a minimum distance from the first passage. Alternatively or additionally a second sensor element can be provided on the second passage in this version, by means of which it can be determined if the separating element is located in a second end position, in which the separating element is located at a minimum distance from the second passage. During the thermal cycling of the thermochemical reactor the time when the heat transfer fluid has been completely extracted from one of the two sub-stores can be determined in this way; since in this case the separating element is located at a minimum distance from the first or second passage. 
     In a preferred embodiment of the assembly, an operating state is adjustable by the control/regulating device in the at least one adjustable valve device of the valve system in which the heat transfer fluid circuit forms a first part circuit. In the first part circuit, the heat transfer fluid circulates between the thermochemical reactor and the second heat reservoir namely in such a manner that heat from the thermochemical reactor is transferred into the second heat reservoir, i.e. into the heat sync. In this way, heat can be discharged from the thermochemical reactor in a particularly effective manner. In this operating state, the first valve device and the second valve device in each case preferably connect the second heat reservoir fluidically to the thermochemical reactor. In this operating state, the position of the third and fourth valve device is irrelevant since flowing through the temporary heat store is not possible. 
     In this operating state, the first sub-store preferably has a maximum volume and the second sub-store a minimum volume. This means that the first sub-store is filled with the heat transfer fluid which substantially has the temperature level of the heat source. 
     In a further preferred embodiment of the assembly, an operating state is adjustable by the control/regulating device in the at least one adjustable valve device of the valve system, in which the heat transfer fluid circuit forms a second part circuit. In this second part circuit, the heat transfer fluid circulates between the thermochemical reactor and the first heat reservoir, so that heat from the first heat reservoir, i.e. from the heat source, is transferred into the thermochemical reactor. 
     In this operating state, the first valve device and the second valve device in each case preferably connect the first reservoir fluidically to the thermochemical reactor. In this operating state, the position of the third and fourth valve device is irrelevant since flowing through the temporary heat store is not possible. 
     In this operating state, the second sub-store preferably has a maximum volume and the first sub-store a minimum volume. This means that the second sub-store is filled with the heat transfer fluid which substantially has the temperature level of the heat sync. 
     In a further preferred embodiment of the assembly, an operating state is adjustable by the control/regulating device in the at least one adjustable valve device of the valve system, in which heat transfer fluid is transported from the first sub-store of the temporary heat store into the thermochemical reactor. At the same time, heat transfer fluid is transported from the thermochemical reactor into the second sub-store. In this way, stored heat can be particularly effectively fed to the thermoelectric reactor at an earlier time. In this operating state, the first valve device and the third valve device preferably fluidically connect the thermochemical reactor, bypassing the first heat reservoir, directly to the first sub-store. In this operating state, the second and the fourth valve device fluidically connect the thermochemical reactor to the second sub-store. 
     In a further preferred embodiment of the assembly, an operating state is adjustable by the control/regulating device in the at least one adjustable valve device of the valve system, in which heat transfer fluid, bypassing the second heat reservoir, is transported into the thermochemical reactor. At the same time, heat transfer fluid, bypassing the first heat reservoir, is transported from the thermochemical reactor into the first sub-store. In this operating state, the first valve device and the fourth valve device preferably fluidically connect the thermochemical reactor, bypassing the second heat reservoir, directly to the second sub-store. The second valve device and the third valve device fluidically connect the thermochemical store directly to the first sub-store. 
     In an advantageous further development, the first and the second heat reservoir and the thermochemical reactor each comprise a fluid inlet or a fluid outlet for introducing and discharging the heat transfer fluid. In this version, the heat transfer fluid comprises a first adjustable valve device, by means of which the fluid inlet of the thermochemical reactor can be optionally connected to the fluid outlet of the first or second heat reservoir. Likewise, the heat transfer fluid circuit comprises a second adjustable valve device by means of which the fluid outlet of the thermochemical reactor can be optionally connected to the fluid inlet of the first or second heat reservoir. 
     Practically, the temporary heat store is connected fluidically parallel to the second valve device so that the fluid inlet of the first heat reservoir fluidically communicates with the first sub-store and the fluid inlet of the second heat reservoir fluidically communicates with the second sub-store. 
     In an advantageous further development, the first valve device and the second valve device each comprise a 3/2-way changeover valve. Particularly advantageously, the third and the fourth valve device are also designed as 3/2-way changeover valves. 
     In a further advantageous further development, the third and the fourth 3/2-way valve are each designed as self-switching valves which, because of the pressure differentials or flow directions that are present, are set into the correct position. This measure renders a functional coupling to the control/regulating device superfluous and thus simplifies the technical construction of the assembly. 
     The invention, furthermore, relates to a method for operating an assembly with a heat transfer fluid circuit preferentially introduced above, in which a thermochemical reactor, two heat reservoirs of different temperature and a temporary heat store are arranged and fluidically connected to one another by means of a heat transfer fluid circuit. 
     The temporary heat store utilised for carrying out the method according to the invention comprises two sub-stores that are thermally and fluidically separated, in which a heat transfer fluid that circulates in the heat transfer fluid circuit can be received thermally and fluidically separated from one another. In accordance with the method according to the invention, for carrying out a temperature change of the thermochemical reactor from a low to a higher temperature level, increasingly warmer heat transfer fluid that is temporarily stored in the first sub-store of the temporary heat store is extracted and, bypassing the first heat reservoir, fed to the thermochemical reactor as a result of which the same is heated. At the same time, initially cool but increasingly warmer heat transfer fluid is discharged from the thermochemical reactor and introduced into the second sub-store of the temporary heat store. 
     For performing a temperature change of the thermochemical reactor from a high to a lower temperature level, increasing cooler heat transfer fluid temporarily stored in the second sub-store of the temporary heat store extracted and, bypassing the second heat reservoir, fed to the thermochemical reactor as a result of which the same is cooled. At the same time, initially warm but increasingly cooler heat transfer fluid is discharged from the thermochemical reactor and introduced into the first sub-store of the temporary heat store. 
     In the method explained above, a high proportion of the heats converted during the temperature change can be temporarily stored and recovered. 
     Further important features and advantages of the invention are obtained from the subclaims, from the drawing and from the associated figure description by way of the drawing. 
     It is to be understood that the features mentioned above and still to be explained in the following cannot only be used in the respective combination stated but also in other combinations or by themselves without leaving the scope of the present invention. 
     Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein same reference numbers relate to same or similar or functionally same components. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       It shows, in each case schematically 
         FIGS. 1 to 4  an assembly according to the invention in different operating states, 
         FIG. 5  the construction of the temporary heat store that is substantial for the invention of the assembly of the  FIGS. 1 to 4  in a detail representation, 
         FIG. 6  a first version of the temporary heat store of  FIG. 5 , 
         FIG. 7  a second version of the temporary heat store of  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an example of an assembly  1  according to the invention, in particular of a refrigeration machine or of a heat pump. The assembly  1  comprises a first heat reservoir  2   a  with a first temperature T 1  and a second heat reservoir  2   b  with a second temperature T 2 . The assembly  1 , furthermore, comprises a thermochemical reactor  5 , which can be or is thermally and fluidically connected to the two heat reservoirs  2   a ,  2   b . For this purpose, the assembly  1  comprises a heat transfer fluid circuit  3 , in which a heat transfer fluid F for transporting heat between the two heat reservoirs  2   a ,  2   b  and the thermochemical reactor  5  is arranged. 
     The term “thermochemical reactor” here is to mean a device in which conversion processes are made to take place by supplying and discharging heat—known to the person skilled in the art as reaction heat, sorption heats or phase change heat—at different temperatures T 1 , T 2 . The thermochemical reactor  5  can comprise a vessel  15  only shown schematically in the figures, in which thermochemical reactions take place, with a heat transfer structure for supplying and discharging the reaction heats. The first temperature T 1  has a greater value than the second temperature T 2 , i.e. the first heat reservoir  2   a  functions as heat source, from which by means of the heat transfer fluid F heat can be transferred to the thermochemical reactor  5 . The second heat reservoir  2   b  by contrast functions as heat sync, to which by means of the heat transfer fluid F heat from the thermochemical reactor  5  can be transferred. 
     Furthermore, a temporary heat store  100  for temporarily storing the heat transfer fluid F is present in the heat transfer fluid circuit  3 . The temporary heat store  100  makes possible a temperature change of the thermochemical reactor  5  from the temperature T 1  to the temperature T 2  and vice versa with very minor energy losses. 
     The construction of the temporary heat store  100  is shown in  FIG. 5  in a schematic detail representation. According to  FIG. 5 , the temporary heat store  100  comprises a first sub-store  101   a  with a variable storage volume  102   a  and, thermally and fluidically separated from the same, a second sub-store  101   b  with variable storage volume  102   b . The volume-variable first sub-store  101   a  of the temporary heat store  100  is designed complementarily to the volume-variable second sub-store  101   b , so that the total volume formed by the two sub-stores  101   a ,  101   b  is always constant. 
     The temporary heat store  100  can also be referred to as sensible short-term heat store, regenerator or temperature changer and represents a component of the assembly  1  that is substantial for the invention, which makes possible a temperature change in the thermochemical reactor  5  with low energy losses in the first place. 
     The temporary heat store  100  is designed for the simultaneous receiving and outputting of a first and a second fluid mass of the heat transfer fluid F with differently layered temperature profile. Furthermore, the temporary heat store  100  is designed for the simultaneous receiving and outputting of the first and second fluid mass of the heat transfer fluid F, wherein the two fluid masses have different temperature layers, which in terms of quality are marked with different shades of grey. The darker the shade of grey, the higher is the temperature level that is present locally. 
     The function principle of the temporary heat store  100  is based on a thermally insulated fluid vessel with end-side openings and large length/cross-section ratio within which an insulated shiftable separating body  106  is arranged, as is schematically shown in  FIG. 5 . 
     In the exemplary scenario of  FIG. 5 , the temporary heat store  100  is realised as vessel  103 . This vessel  103  comprises a housing  104 . The housing  104  delimits an interior  107 , in which a separating element  106  is moveably arranged, which thermally and fluidically insulates the two sub-stores  101   a ,  101   b  from one another. The separating element  106  subdivides the interior  107  into a volume-variable first sub-store  101   a  and a likewise volume-variable second sub-store  101   b  that is thermally and fluidically insulated from the first sub-store  101   a . Advantageously, the housing wall  104  of the temporary heat store  100  is designed so that said housing wall  104  only has a small thermal mass and is embodied insulated towards the surroundings. 
     As is evident from the figures, the thermochemical reactor  5  and the temporary heat store  100  each have separate vessels  15  and  103  respectively. 
     As is evident from  FIG. 5 , a first passage  108   a  for introducing and discharging the heat transfer fluid F with the temperature T 1  into the first sub-store  101   a  and from the first sub-store  101   a  is present in the housing  104 . Furthermore, a second passage  108   b  for introducing and discharging the heat transfer fluid F with the temperature T 2  into the second sub-store  101   b  or from the second sub-store  101   b  is present in the housing  104 . 
     The housing  104  is designed as a tubular body  105  which extends in a straight line along an axial direction A. For forming the two volume-variable sub-stores  101   a ,  101   b  the separating element  106  moveably lies against the inside  112  of a circumferential wall  111  of the tubular body  105  along the axial direction A. The first passage  108   a  is arranged on as first longitudinal end  109   a . The second passage  108   b  is arranged on a second longitudinal end  109   b  located opposite the first longitudinal end  109   a.    
     On the first passage of the temporary heat store a first sensor element  110   a  is provided, by means of which it can be determined if the separating element  106  is located in a first end position, in which it is located at a minimum distance from the first passage  108   a . Analogously, a second sensor element  110   b  is provided on the second passage  108   b , by means of which it can be determined if the separating element  106  is located in a second end position, in which it is located at a minimum distance from the second passage  108   b.    
     As illustrated in  FIG. 3 , the temporary heat store  100 , with the separating element  106  arranged on the very left, i.e. on the first passage  108   a , can be filled with a temperature-layered liquid column of the heat transfer fluid F, wherein the temperature level that is present at the separating element approximately corresponds to the temperature T 2  and the temperature level that is present at the outlet  108   b  reaches closely to the temperature T 1 . By way of heat transfer fluid F of the temperature T 1  that is initially hot but becoming ever cooler flowing in from the left via the first passage  108   a , the separating element  106  can be shifted to the right, towards the second passage  108   b , as a result of which the temporary heat store  100  is filled with a temperature-layered liquid column of the heat transfer fluid F, wherein the temperature level that is present at the separating element approximately corresponds to the temperature T 1  and the temperature level that is present at the outlet  108   a  almost reaches up to the temperature T 2 . At the same time, the liquid column that is layered from the temperature T 1  to the temperature T 2  can be expelled through the second passage  108   b  to the right until the separating element  106  is located at the second passage  108   b  and the temperature-layered liquid column of the heat transfer fluid F has been completely exchanged. 
     Temperature profiles of the liquid columns of the heat transfer fluid F stored in the sub-stores of the temporary heat store bring about that during an expulsion of the temperature-layered liquid column from the second sub-store heat transfer fluid that is initially warm but becomes ever cooler is expelled. Thus, this sub-store can serve for the sliding cooling of a thermochemical reactor  5  as is evident from  FIG. 4 . 
     Complementarily thereto, initially cool heat transfer fluid that however becomes ever warmer is expelled from the first sub-store during an expulsion of the temperature-layered liquid column. Thus, this sub-store can serve for the sliding heating of a thermochemical reactor  5  as is evident from  FIG. 2 . 
     Again looking at  FIG. 1  it is evident that in the heat transfer fluid circuit  4  a delivery device  8  for driving the heat transfer fluid F is provided. 
     Furthermore, a valve system  9  is present in the heat transfer fluid circuit  3 , which comprises four adjustable valve devices, namely a first adjustable valve device  10   a , a second adjustable valve device  10   b , a third adjustable valve device  10   c  and a fourth adjustable device  10   d . By means of the four valve devices  10   a ,  10   b ,  10   c ,  10   d , heat transport between the two heat reservoirs  2   a ,  2   b , the thermochemical reactor  5  and the temporary heat store  100  can be adjusted and consequently controlled. For controlling the valve devices  10   a ,  10   b  of the valve system  9 , a control/regulating device  4  is provided which interacts with the valve devices  10   a ,  10   b.    
     The first and the second heat reservoir  2   a ,  2   b  as well as the thermochemical reactor  5  each have a fluid inlet  11   a ,  11   b ,  11   c  and a fluid outlet  12   a ,  12   b ,  12   c  for introducing and for discharging the heat transfer fluid F respectively. 
     By means of the first adjustable valve device  10   a , the fluid inlet  11   b  of the thermochemical reactor  5  can be optionally connected to the fluid outlet  12   a ,  12   c  of the first or second heat reservoir  2   a ,  2   b . By means of the second adjustable valve device  10   b , the fluid outlet  12   b  of the thermochemical reactor  5  can be optionally connected to the fluid inlet  11   a ,  11   c  of the first or second heat reservoir  2   a ,  2   b . By means of the third adjustable valve device  10   c , the first sub-store  101   a  can be optionally connected via the first heat reservoir  2   a  or directly to the first valve device  10   a . By means of the fourth valve device  10   d , the second sub-store  101   b  can be optionally connected via the second heat reservoir  2   b  or directly to the first valve device  10   a.    
     As is evident from  FIG. 1 , the third valve device  10   c  can be directly connected to the first valve device  10   a  by means of a first fluid line  6   a . Likewise, the fourth valve device  10   d  is fluidically connected directly to the first valve device  10   a  by means of a second fluid line  6   b . The first fluid line  6   a  is realised as a bypass line of the first heat reservoir  2   a . The second fluid line  6   b  is realised as a bypass line of the second heat reservoir  2   b.    
     As is evident from  FIG. 1 , furthermore, the temporary heat store  100  is fluidically connected in parallel with the second valve device  10   b , so that the fluid inlet  11   a  of the first heat reservoir  2   a  fluidically communicates with the first sub-store  101   a  and the fluid inlet  11   c  of the second heat reservoir  2   b  fluidically connects with the second sub-store. 
     The four valve devices  10   a - 10   d  are each designed as 3/2-way changeover valves  13   a ,  13   b ,  13   c ,  13   d . Preferably, the third and fourth 3/2-way valves are designed as self-switching valves. 
     In the following, a complete thermal cycle of the thermochemical reactor  5  is now explained, during which the thermochemical reactor  5  is changed over between a first state with temperature T 1  of the first heat reservoir  2   a  and a second state with temperature T 2  of the second heat reservoir  2   b  and back into the starting state. 
     By the control/regulating device  4 , the valve devices  10   a ,  10   b  of the valve system  9  can be adjusted into an operating state which is schematically shown in  FIG. 1 . This operating state can be referred to as “heat discharge mode”. In this operating state, the first sub-store  101   a  has a maximum volume and the second sub-store  101   b  a minimum volume, i.e. the first sub-store  101   a  of the temporary heat store  100  is filled with heat transfer fluid F, which has a temperature layering rising from the left to the right closely up to the temperature T 1 . Second sub-store  101   b  by contrast is empty. In this operating state, the heat transfer fluid circuit  3  forms a first part circuit  14   a  in which the heat transfer fluid F circulates between the thermochemical reactor  5  and the second heat reservoir  2   b . In this operating state, the heat transfer fluid F transfers heat from the thermochemical reactor  5  into the second heat reservoir  2   b , i.e. reaction heat is discharged from the thermochemical reactor  5  near the temperature level T 2 . In this operating state, the first valve device  10   a  and the second valve device  10   b  each connect the second heat reservoir  2   b  fluidically to the thermochemical store  5 . The third and the fourth valve device  10   c ,  10   d  in this operating mode are not flowed through, which is why their positions are not relevant and can be any. 
     During the course of the thermal cycling, the thermochemical reactor  5  is now changed over into a state with temperature T 1  of the first heat reservoir  2   a , as a result of which a temperature change is carried out in order to substantially heat up the thermal masses. To this end, the four valve devices  10   a  to  10   d  are initially adjusted by the control/regulating device  4  into an operating state that is shown in  FIG. 2 . In the operating state shown in  FIG. 2 , the four valve devices  10   a  to  10   d  are adjusted in such a manner that the heat transfer fluid F is transported from the first sub-store  101   a  of the temporary heat store  100  into the thermochemical reactor  5 . Furthermore, heat transfer fluid F is transported from the thermochemical reactor  5  into the second sub-store  101   b.    
     For this purpose, the first valve device  10   a  and the third valve device  10   c  fluidically connect the thermochemical store  5 , bypassing the first heat reservoir  2   a , directly to the first sub-store  101   a . The second and the fourth valve device  10   b ,  10   d  fluidically connect the thermochemical reactor  5  to the second sub-store  101   b.    
     In this operating state, the temperature-layered heat transfer fluid F of the first sub-store  101   a  of the temporary heat store  100  is fed to the thermochemical reactor  5  via the line  6   a , as a result of which the same is heated closely up to the limit temperature T 1 . Conversely, the second sub-store  101   b  is filled with heat transfer fluid F with increasing temperature, as a result of which the liquid column stored there is subjected to a temperature layering the temperature of which increases from the left to the right within the temperature limits T 2  and T. The variable storage volume  102   a  of the first sub-store  101   a  decreases through movement of the separating element  106 , the variable volume  102   b  of the second sub-store  101   b  increases at the same time. In this operating state, the temperature of the thermochemical reactor increases from T 2  to T 1 . 
     As soon as the heat transfer fluid F temporarily stored in the first sub-store  101   a  of the temporary heat store  100  has been completely extracted from the temporarily store  100 , the separating element  106  is located in the abovementioned first end position, which can be detected by the control/regulating device  4  by means of the first sensor element  110   a.    
     The operating state shown in  FIG. 2  can also be referred to as “heating-up mode”. In this operating state, increasingly hotter fluid from the temporary heat store  100  is fed to the thermochemical store  100 , as a result of which the same is brought with stored heat from the lower temperature level, near the temperature T 2 , to the upper temperature level, near the temperature T 1 . 
     Following this, the two valve devices  10   a ,  10   b  are switched by the control/regulating device  4  into an operating state which is schematically shown in  FIG. 3 . 
     In the operating state schematically shown in  FIG. 3 , the heat transfer fluid circuit  3  forms a second part circuit  14   b , in which the heat transfer fluid F circulates between the thermochemical reactor  5  and the first heat reservoir  2   a . In this way, heat is transported from the first heat reservoir  2   a  to the thermochemical reactor  5 . 
     For this purpose, the first valve device  10   a  and the second valve device  10   b  each fluidically connect the first heat reservoir  2   a  to the thermochemical reactor  5 . The third and the fourth valve device  10   c ,  10   d  are not flowed through in this operating mode which is why their positions are not relevant, i.e. can be any. 
     In this operating state, reaction heat near the temperature T 1  is transferred from the first heat reservoir  2   a  to the thermochemical reactor  5 . In this operating state, the second sub-store  101   b  has a maximum volume and the first sub-store  101   a  a minimum volume, i.e. the second sub-store  101   b  of the temporary heat store  100  is filled with heat transfer fluid F, which has a temperature layering which rises from the left to the right closely up to the temperature T 1 . By contrast, the first sub-store  101   a  is empty. The operating state shown in  FIG. 3  can be referred to as “heat supply mode”. 
     Following this, the valve devices  10   a ,  10 ,  10   c ,  10   d  are adjusted by the control/regulating device  4  into an operating shown in  FIG. 4 . 
     In the operating state shown in  FIG. 4 , the so-called “cooling-down mode”, the valve devices  10   a  to  10   d  are adjusted in such a manner that the heat transfer fluid F stored in the second sub-store  101   b  in a temperature-layered manner, bypassing the second heat reservoir  2   b , is transported into the thermochemical reactor  5 . Simultaneously with this, heat transfer fluid F is transported from the thermochemical reactor  5  into the first sub-store  101   a  of the temporary heat store  100 . In the operating state according to  FIG. 4 , the first valve device  10   a  and the fourth valve device  10   d  fluidically connect the thermochemical store  5  bypassing the second heat reservoir  2   b  directly to the second sub-store  101   b . The second valve device  10   b  and the third valve device  10   c  fluidically connect the thermochemical store  5  directly to the first sub-store  101   a.    
     As soon as the temperature-layered heat transfer fluid F that is temporarily stored in the second sub-store  101   b  of the temporary heat store  100  has been completely extracted from the temporary heat store  100 , the separating element  106  is located in the abovementioned second end position, which can be detected by the control/regulating device  4  with the help of the second sensor element  110   b . In this state, the first sub-store  101   a  is completely filled with the heat transfer fluid F (see  FIG. 1 ). The valve devices  10   a  to  10   b  are again switched into the operating state shown in  FIG. 1  by the control/regulating device  4  and a complete changeover cycle of the thermochemical reactor  5  is concluded. 
       FIG. 6  shows a further development of the vessel  103  of  FIG. 5 . In the case of the vessel  103  of  FIG. 6 , a helical structure  113  is arranged in the interior  107  of the housing  104 . This helical structure  113  imparts the interior  107  the geometry of a fluid passage  114  with helical geometry. Here, the fluid passage  114  is delimited by the helical structure  113  and by the housing  104 , in particular by the circumferential wall  111  of the same. The helical structure  103  can be designed as insert  115  arranged in the interior. The helical structure  113  can comprise at least 10 windings  116 , preferably even at least 20 windings. The separating element  106  is designed adjustable along the helical fluid passage  114 . This means the geometrical shaping of the separating element  106  is selected in such a manner that it is adjustable in the interior  107  along the fluid passage  114 , which is delimited by the circumferential wall  111  and the helical structure  113 . 
       FIG. 7  shows a further version of the example of  FIG. 5 , in the case of which the vessel  103  is realised as a body  117  formed hose-like, which along an extension direction E does not extend in a straight line at least in sections. In this version, the separating element  106  for forming the two volume-variable sub-stores  101   a ,  101   b  moveably lies against the inside  112  of the circumferential wall  111  of the hose-like body  117  along the extension direction E. This version allows a spatially particularly compact assembly of the vessel  103 . Preferably, a length of the housing  104  or of the hose-like body  117  measured along the extension direction E amounts to at least 20 times, preferentially at least 50 times of a transverse direction Q measured transversely to the extension direction E.