Patent Application
20190186792
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.
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.
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.
It shows, in each case schematically
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 T1, T2. 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 T1 has a greater value than the second temperature T2, i.e. the first heat reservoir 2a 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 2b 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 T1 to the temperature T2 and vice versa with very minor energy losses.
The construction of the temporary heat store 100 is shown in
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
In the exemplary scenario of
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
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 101a, 101b 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 108a is arranged on as first longitudinal end 109a. The second passage 108b is arranged on a second longitudinal end 109b located opposite the first longitudinal end 109a.
On the first passage of the temporary heat store a first sensor element 110a 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 108a. Analogously, a second sensor element 110b is provided on the second passage 108b, 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 108b.
As illustrated in
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
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
Again looking at
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 10a, a second adjustable valve device 10b, a third adjustable valve device 10c and a fourth adjustable device 10d. By means of the four valve devices 10a, 10b, 10c, 10d, heat transport between the two heat reservoirs 2a, 2b, the thermochemical reactor 5 and the temporary heat store 100 can be adjusted and consequently controlled. For controlling the valve devices 10a, 10b of the valve system 9, a control/regulating device 4 is provided which interacts with the valve devices 10a, 10b.
The first and the second heat reservoir 2a, 2b as well as the thermochemical reactor 5 each have a fluid inlet 11a, 11b, 11c and a fluid outlet 12a, 12b, 12c for introducing and for discharging the heat transfer fluid F respectively.
By means of the first adjustable valve device 10a, the fluid inlet 11b of the thermochemical reactor 5 can be optionally connected to the fluid outlet 12a, 12c of the first or second heat reservoir 2a, 2b. By means of the second adjustable valve device 10b, the fluid outlet 12b of the thermochemical reactor 5 can be optionally connected to the fluid inlet 11a, 11c of the first or second heat reservoir 2a, 2b. By means of the third adjustable valve device 10c, the first sub-store 101a can be optionally connected via the first heat reservoir 2a or directly to the first valve device 10a. By means of the fourth valve device 10d, the second sub-store 101b can be optionally connected via the second heat reservoir 2b or directly to the first valve device 10a.
As is evident from
As is evident from
The four valve devices 10a-10d are each designed as 3/2-way changeover valves 13a, 13b, 13c, 13d. 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 T1 of the first heat reservoir 2a and a second state with temperature T2 of the second heat reservoir 2b and back into the starting state.
By the control/regulating device 4, the valve devices 10a, 10b of the valve system 9 can be adjusted into an operating state which is schematically shown in
During the course of the thermal cycling, the thermochemical reactor 5 is now changed over into a state with temperature T1 of the first heat reservoir 2a, 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 10a to 10d are initially adjusted by the control/regulating device 4 into an operating state that is shown in
For this purpose, the first valve device 10a and the third valve device 10c fluidically connect the thermochemical store 5, bypassing the first heat reservoir 2a, directly to the first sub-store 101a. The second and the fourth valve device 10b, 10d fluidically connect the thermochemical reactor 5 to the second sub-store 101b.
In this operating state, the temperature-layered heat transfer fluid F of the first sub-store 101a of the temporary heat store 100 is fed to the thermochemical reactor 5 via the line 6a, as a result of which the same is heated closely up to the limit temperature T1. Conversely, the second sub-store 101b 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 T2 and T. The variable storage volume 102a of the first sub-store 101a decreases through movement of the separating element 106, the variable volume 102b of the second sub-store 101b increases at the same time. In this operating state, the temperature of the thermochemical reactor increases from T2 to T1.
As soon as the heat transfer fluid F temporarily stored in the first sub-store 101a 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 110a.
The operating state shown in
Following this, the two valve devices 10a, 10b are switched by the control/regulating device 4 into an operating state which is schematically shown in
In the operating state schematically shown in
For this purpose, the first valve device 10a and the second valve device 10b each fluidically connect the first heat reservoir 2a to the thermochemical reactor 5. The third and the fourth valve device 10c, 10d 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 T1 is transferred from the first heat reservoir 2a to the thermochemical reactor 5. In this operating state, the second sub-store 101b has a maximum volume and the first sub-store 101a a minimum volume, i.e. the second sub-store 101b 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 T1. By contrast, the first sub-store 101a is empty. The operating state shown in
Following this, the valve devices 10a, 10, 10c, 10d are adjusted by the control/regulating device 4 into an operating shown in
In the operating state shown in
As soon as the temperature-layered heat transfer fluid F that is temporarily stored in the second sub-store 101b 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 110b. In this state, the first sub-store 101a is completely filled with the heat transfer fluid F (see
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2016 215 374.9 | Aug 2016 | DE | national |
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.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2017/000988 | 8/16/2017 | WO | 00 |
