Refrigerating device

Abstract

To solve the problem in a vapor compression type refrigeration cycle which can adjust ability by changing the circulation amount of a refrigerant, but in which it is necessary to change the adsorption amount or desorption amount of the refrigerant in order to adjust ability in an adsorption type refrigeration cycle.SOLUTION: A refrigerating device 100 comprises a refrigerant flow passage 111, a compressor 131, an adsorbent, a first adsorber 133, a second adsorber 134, and a control unit 105. The compressor 131 sucks and compresses a low-pressure refrigerant, and discharges it as a high-pressure refrigerant. The adsorbent adsorbs and desorbs a refrigerant in accordance with a pressure change of the refrigerant. The first adsorber 133 and the second adsorber 134 are connected to a discharge side or a suction side of the compressor 131, so that when the adsorbent adsorbs and desorbs the refrigerant, generated heat or cold is recovered. The control unit changes an operation mode. In a first operation mode, a difference between the pressure of the high-pressure refrigerant and the pressure of the low-pressure refrigerant is a first value. In a second operation mode, the difference is a second value different from the first value.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] Regarding refrigeration equipment. [Background technology]

[0002] Conventionally, as disclosed in Patent Document 1 (US Patent Application Publication No. 2023 / 0417459), refrigeration devices equipped with an adsorption refrigeration cycle that utilizes the heat generated when a refrigerant is adsorbed and desorbed onto an adsorbent material such as a porous metal complex have been used. Summary of the Invention [Problem to be solved by the invention]

[0003] In a vapor compression refrigeration cycle, which utilizes the heat of condensation and heat of evaporation of a refrigerant, the capacity can be adjusted by changing the amount of refrigerant circulated. However, in an adsorption refrigeration cycle, the capacity can be adjusted by changing the amount of refrigerant adsorbed onto the adsorbent or the amount of refrigerant desorbed from the adsorbent. [Means for solving the problem]

[0004] A refrigeration apparatus according to a first aspect includes a refrigerant flow path through which a refrigerant flows, a compressor, an adsorbent, a first heat recovery unit, a second heat recovery unit, and a control unit. The compressor draws in and compresses low-pressure refrigerant, and discharges it as high-pressure refrigerant. The adsorbent adsorbs and desorbs the refrigerant according to changes in the refrigerant pressure. The first heat recovery unit is connected to the discharge side of the compressor and recovers hot heat generated when the adsorbent adsorbs the refrigerant. The second heat recovery unit is connected to the suction side of the compressor and recovers cold heat generated when the adsorbent desorbs the refrigerant. The control unit changes the operation mode. The operation modes include a first operation mode and a second operation mode. In the first operation mode, the difference between the pressure of the high-pressure refrigerant and the pressure of the low-pressure refrigerant (operating differential pressure) is a first value. In the second operation mode, the operating differential pressure is a second value different from the first value.

[0005] The refrigeration apparatus of the first aspect can adjust the capacity of the refrigeration apparatus by adjusting the operating differential pressure, which is the difference between the pressure in the high-pressure region and the pressure in the low-pressure region of the refrigerant flow path.

[0006] A refrigeration device of a second aspect is the refrigeration device of the first aspect, wherein the control unit changes the operating mode by adjusting the operating differential pressure by changing at least one of the timing at which the compressor is started and the timing at which the compressor is stopped.

[0007] A refrigeration apparatus according to a third aspect is the refrigeration apparatus according to the first aspect, wherein the control unit changes the operation mode by adjusting the operating differential pressure by changing the rotation speed of the compressor without stopping the compressor.

[0008] A refrigeration apparatus according to a fourth aspect is the refrigeration apparatus according to any one of the first to third aspects, further comprising an expansion mechanism. The expansion mechanism reduces the pressure of a high-pressure refrigerant to a low-pressure refrigerant. The adsorbent flows through at least a portion of the refrigerant flow path together with the refrigerant circulating through the refrigerant flow path. The control unit controls the expansion mechanism to adjust the operating differential pressure, thereby changing the operation mode.

[0009] A refrigeration apparatus according to a fifth aspect is the refrigeration apparatus according to any one of the first to third aspects, further comprising a switching mechanism. One of the first heat recovery unit and the second heat recovery unit is a first adsorber having an adsorbent, and the other is a second adsorber having an adsorbent. The switching mechanism is capable of switching the refrigerant flow path between a first state and a second state. In the first state, the discharge side of the compressor is connected to the first adsorber to create a high-pressure state inside the first adsorber, and the suction side of the compressor is connected to the second adsorber to create a low-pressure state inside the second adsorber. In the second state, the suction side of the compressor is connected to the first adsorber to create a low-pressure state inside the first adsorber, and the discharge side of the compressor is connected to the second adsorber to create a high-pressure state inside the second adsorber. When the refrigerant flow path is in the first state, the first heat recovery unit is the first adsorber, and the second heat recovery unit is the second adsorber. When the refrigerant flow path is in the second state, the first heat recovery unit is the second adsorber, and the second heat recovery unit is the first adsorber.

[0010] A refrigeration apparatus according to a sixth aspect is the refrigeration apparatus according to the fifth aspect, further comprising a bypass flow path and a bypass valve. The bypass flow path connects the first heat recovery unit and the second heat recovery unit without passing through the compressor. The bypass valve is provided in the bypass flow path. The control unit changes the operation mode by adjusting the operating differential pressure by changing the opening of the bypass valve.

[0011] A refrigeration apparatus according to a seventh aspect is the refrigeration apparatus according to the fifth or sixth aspect, further comprising a first pressure vessel and a second pressure vessel. The first pressure vessel is provided in the refrigerant flow path between the discharge side of the compressor and the switching mechanism. The second pressure vessel is provided in the refrigerant flow path between the suction side of the compressor and the switching mechanism.

[0012] A refrigeration apparatus according to an eighth aspect is the refrigeration apparatus according to the seventh aspect, wherein the operating differential pressure is the difference between the internal pressure of the first pressure vessel and the internal pressure of the second pressure vessel.

[0013] A refrigeration device according to a ninth aspect is the refrigeration device according to any one of the first to eighth aspects, wherein the adsorbent includes a metal-organic framework including metal ions and organic ligands.

[0014] A refrigeration device according to a tenth aspect is the refrigeration device according to any one of the first to ninth aspects, wherein the refrigerant flowing through the refrigerant flow passage is selected from the group consisting of carbon dioxide, hydrocarbon refrigerant, ammonia, and water. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a schematic diagram of a refrigeration device equipped with an adsorption refrigeration cycle. [Figure 2] 4 is a graph showing the relationship between the adsorption amount of the adsorbent and the pressure of the refrigerant. [Figure 3] 1 is a graph showing the relationship between the adsorption amount of an adsorbent and the enthalpy of a refrigerant. [Figure 4] 1 is a schematic diagram of a refrigeration device 100 of a first embodiment. [Figure 5] 1 is a block diagram of a refrigeration device 100 of a first embodiment. [Figure 6]FIG. 10 is a schematic diagram of a refrigeration device 200 according to a second embodiment. [Figure 7] FIG. 10 is a block diagram of a refrigeration device 200 according to a second embodiment. [Figure 8] 10 is a schematic diagram of a first adsorption device 221 and a second adsorption device 222 according to a second embodiment. FIG. [Figure 9] FIG. 10 is a schematic diagram of a refrigeration device 200 according to a modified example A. [Figure 10] FIG. 10 is a block diagram of a refrigeration device 200 according to a modified example A. [Figure 11] FIG. 10 is a schematic diagram of a refrigeration device 200 according to a modified example B. [Figure 12] FIG. 10 is a block diagram of a refrigeration device 200 according to a modification B. DETAILED DESCRIPTION OF THE INVENTION

[0016] (1) Principle of refrigeration equipment The refrigeration device of this embodiment includes an adsorption refrigeration cycle that functions as a heat pump that utilizes heat generated when an adsorbent adsorbs a refrigerant and when the adsorbent desorbs the refrigerant. The refrigeration device is, for example, an air conditioner.

[0017] The refrigeration apparatus of this embodiment includes a circulation type refrigeration apparatus in which the adsorbent is circulated, and a non-circulation type refrigeration apparatus in which the adsorbent is not circulated.

[0018] (1-1) Circulating refrigeration equipment As shown in Fig. 1, the circulation type refrigeration system 1 includes a refrigerant circuit 11 through which a refrigerant circulates, and an adsorption circuit 12 through which an adsorbent circulates. The refrigeration system 1 includes a mechanism for bringing the refrigerant circulating in the refrigerant circuit 11 into contact with the adsorbent circulating in the adsorption circuit 12. For the sake of explanation, the refrigerant circuit 11 and the adsorption circuit 12 are depicted in Fig. 1 as independent circuits.

[0019] The refrigeration system 1 has an adsorption unit 21 and a desorption unit 22. The adsorption unit 21 and the desorption unit 22 each include a part of the refrigerant circuit 11 and a part of the adsorption circuit 12. In the adsorption unit 21 and the desorption unit 22, the refrigerant can move freely between the refrigerant circuit 11 and the adsorption circuit 12. The adsorbent cannot move between the refrigerant circuit 11 and the adsorption circuit 12. In the adsorption unit 21, the refrigerant that flows from the refrigerant circuit 11 into the adsorption circuit 12 is adsorbed by the adsorbent flowing in the adsorption circuit 12. In the desorption unit 22, the refrigerant desorbed from the adsorbent flowing in the adsorption circuit 12 flows from the adsorption circuit 12 into the refrigerant circuit 11.

[0020] The refrigerant circuit 11 has a compressor 31 and an expansion mechanism 32. The compressor 31 compresses the refrigerant circulating within the refrigerant circuit 11. The expansion mechanism 32 decompresses the refrigerant circulating within the refrigerant circuit 11. The compressor 31 is, for example, a rotary compressor. The expansion mechanism 32 is, for example, an electronic expansion valve. In the refrigerant circuit 11, the refrigerant is compressed by the compressor 31, passes through the adsorption section 21, is decompressed by the expansion mechanism 32, passes through the desorption section 22, and is compressed again by the compressor 31.

[0021] The refrigerant circuit 11 has a high-pressure region and a low-pressure region. In the high-pressure region, refrigerant flows after being compressed by the compressor 31 and before being decompressed by the expansion mechanism 32. In the low-pressure region, refrigerant flows after being decompressed by the expansion mechanism 32 and before being compressed by the compressor 31. The high-pressure region is included in the adsorption section 21. The low-pressure region is included in the desorption section 22.

[0022] The refrigerant circulating in the refrigerant circuit 11 is selected from the group consisting of, for example, carbon dioxide, hydrocarbon refrigerant, ammonia, and water. The hydrocarbon refrigerant is selected from the group consisting of, for example, propane, butane, and isobutane.

[0023] The adsorption circuit 12 has a booster 41 and a pressure reducer 42. The booster 41 boosts the pressure of the adsorbent circulating through the adsorption circuit 12. The pressure reducer 42 reduces the pressure of the adsorbent circulating through the adsorption circuit 12. The booster 41 is, for example, a powder pump. The pressure reducer 42 is, for example, a powder valve. In the adsorption circuit 12, the adsorbent is boosted by the booster 41, passes through the adsorption section 21, is depressurized by the pressure reducer 42, passes through the desorption section 22, and is again boosted by the booster 41. Depending on the configuration of the refrigeration system 1, the adsorption circuit 12 may not have the booster 41 and the pressure reducer 42.

[0024] The adsorption circuit 12 may further include a heat exchanger 43. The heat exchanger 43 exchanges heat between the upstream side of the pressure booster 41 and the upstream side of the pressure reducer 42. The heat exchanger 43 transfers part of the heat of the adsorbent flowing between the adsorption unit 21 and the pressure reducer 42 to the adsorbent flowing between the desorption unit 22 and the pressure booster 41.

[0025] The adsorbent circulating through the adsorption circuit 12 includes a metal-organic framework (MOF) containing metal ions and organic ligands. A metal-organic framework (MOF) is a porous material with a very large specific surface area obtained by the reaction of metal ions with organic ligands. In the MOF, organic ligands are linked to metal ions to form a polymer structure with numerous internal openings. The opening size and topology of the MOF can be adjusted by selecting and combining metal ions and organic ligands. The opening size of the MOF can be adjusted by selecting and combining metal ions and organic ligands, enabling selective adsorption of target substances. The MOF can be used, for example, as a porous material capable of selectively storing and separating molecules and ions. In this embodiment, the MOF is used as an adsorbent for adsorbing and desorbing a refrigerant. Examples of the MOF include MOF-5, MOF-200, UiO-66, and MIL-101. The adsorbent is, for example, a powder of a metal-organic framework.

[0026] The refrigeration device 1 may have a configuration including a flow path where the refrigerant circuit 11 and the adsorption circuit 12 join together. In this case, the refrigeration device 1 has a flow path that is part of the refrigerant circuit 11 and the adsorption circuit 12 and through which the mixture of refrigerant and adsorbent flows. Alternatively, the refrigeration device 1 may have only one circuit through which the mixture of refrigerant and adsorbent circulates.

[0027] (1-2) Non-circulating refrigeration equipment The non-circulating refrigeration system 1 includes a refrigerant circuit 11 through which a refrigerant flows, but does not include an adsorption circuit 12 through which an adsorbent circulates. In the non-circulating refrigeration system 1, the adsorbent is provided in the refrigerant circuit 11, and the position of the adsorbent is fixed. Specifically, the adsorbent is fixed in the refrigerant circuit 11 included in the adsorption unit 21 and the desorption unit 22. The non-circulating refrigeration system 1 can use the same refrigerant and adsorbent as the circulating refrigeration system 1.

[0028] The non-circulating refrigeration system 1 includes a pair of adsorber units each having the functions of both an adsorption unit 21 and a desorption unit 22. While one of the pair of adsorber units functions as the adsorption unit 21, the other functions as the desorption unit 22. While one of the pair of adsorber units functions as the desorption unit 22, the other functions as the adsorption unit 21. The configuration of the non-circulating refrigeration system 1 will be described later with specific examples.

[0029] (2) Operation The operation of the circulation type refrigeration system 1 will be described with reference to the drawings. The adsorbent adsorbs and desorbs the refrigerant circulating in the refrigerant circuit 11. The adsorbent adsorbs and desorbs the refrigerant according to changes in the pressure of the refrigerant circulating in the refrigerant circuit 11. Specifically, the adsorbent adsorbs the refrigerant under high pressure and desorbs the refrigerant under low pressure.

[0030] The high-pressure region of the refrigerant circuit 11 is assumed to be filled with refrigerant at a pressure pH and a temperature TH. The low-pressure region of the refrigerant circuit 11 is assumed to be filled with refrigerant at a pressure pL and a temperature TL. The pressure pH is higher than the pressure pL. The temperature TH is higher than the temperature TL. The adsorbent adsorbs the refrigerant in the high-pressure region of the refrigerant circuit 11. The adsorbent desorbs the refrigerant in the low-pressure region of the refrigerant circuit 11. In the adsorption section 21, the refrigerant flowing through the high-pressure region of the refrigerant circuit 11 flows into the adsorption circuit 12 and is adsorbed by the adsorbent. In the desorption section 22, the refrigerant desorbed from the adsorbent flowing through the adsorption circuit 12 flows into the low-pressure region of the refrigerant circuit 11.

[0031] The operation of the heat pump cycle of the refrigeration device 1 will be described with reference to Figures 1-3. Figure 1-3 shows the refrigerant cycle a→b→c→d→a in the refrigerant circuit 11 and the adsorbent cycle a'→b'→c'→d'→a' in the adsorption circuit 12. The graph in Figure 2 shows the adsorption amount, which is the mass of refrigerant adsorbed on the adsorbent per unit mass, and the change in pressure of the refrigerant adsorbed on the adsorbent in the heat pump cycle. The graph in Figure 3 shows the adsorption amount of the adsorbent and the change in enthalpy of the refrigerant adsorbed on the adsorbent in the heat pump cycle. In the refrigeration device 1, heat is allowed to flow freely between the refrigerant circuit 11 and the adsorption circuit 12.

[0032] In the refrigerant circuit 11, the refrigerant is compressed by the compressor 31 (a→b). In the adsorption circuit 12, the adsorbent is pressurized by the booster 41 (a'→b'). As a result, the pressure of the refrigerant and the adsorbent increases from pL to pH. During this process, a portion of the heat Q1 generated by the adiabatic compression of the refrigerant is transferred to the adsorbent. In other words, the refrigerant is cooled by transferring heat to the adsorbent while being compressed. As a result, the temperature of the adsorbent increases from TL to TH.

[0033] Next, in the adsorption unit 21, the refrigerant is gradually adsorbed onto the adsorbent while releasing heat Q2 (b' → c'). During this process, the adsorption amount of the adsorbent increases from mL to mH. As a result, in the adsorption unit 21, most of the refrigerant in the refrigerant circuit 11 is adsorbed onto the adsorbent in the adsorption circuit 12. As shown by the hatched arrows in the adsorption unit 21 in FIG. 1, in the adsorption unit 21, the refrigerant in the refrigerant circuit 11 moves to the adsorption circuit 12 and is adsorbed onto the adsorbent.

[0034] Next, in the adsorption circuit 12, the adsorbent is depressurized by the pressure reducer 42 (c' → d'). As a result, the pressure of the adsorbent decreases from pH to pL. During this process, the temperature of the adsorbent decreases from TH to TL due to isenthalpic expansion of the refrigerant desorbed from the adsorbent. Furthermore, due to the temperature difference between the refrigerant and the adsorbent, the depressurized adsorbent in the adsorption circuit 12 is cooled and provides heat Q3 to the refrigerant in the refrigerant circuit 11. Furthermore, heat Q5 is provided by the heat exchanger 43 from the adsorbent before being depressurized to the adsorbent before being pressurized.

[0035] Next, in the desorbing section 22, the refrigerant is gradually desorbed from the adsorbent while absorbing heat Q4 (d'→a'). During this process, the adsorption amount of the adsorbent decreases from mH to mL. As a result, most of the refrigerant adsorbed on the adsorbent in the adsorption circuit 12 is desorbed and flows into the refrigerant circuit 11. As shown by the hatched arrows in the desorbing section 22 in FIG. 1, in the desorbing section 22, the refrigerant desorbed from the adsorbent in the adsorption circuit 12 moves to the refrigerant circuit 11.

[0036] As shown in Figure 2, during the adsorption process (b' → c') in which the refrigerant is adsorbed onto the adsorbent, the pressure is pH, and the adsorption capacity of the adsorbent increases from mL to mH. During the desorption process (d' → a') in which the refrigerant is desorbed from the adsorbent, the pressure is pL, and the adsorption capacity of the adsorbent decreases from mH to mL. As shown in Figure 3, during the adsorption process, the enthalpy decreases by Δh1. During the desorption process, the enthalpy increases by Δh2. During the adsorption process, the heat Q2 released from the adsorption section 21 is proportional to Δh1. During the desorption process, the heat Q4 absorbed by the desorption section 22 is proportional to Δh2.

[0037] In the refrigeration device 1, heat Q2 is released in the adsorption section 21 (first heat recovery section), generating hot heat, and heat Q4 is absorbed in the desorption section 22 (second heat recovery section), generating cold. When the hot heat generated in the adsorption section 21 is recovered by another heat medium, the temperature of the heat medium increases. When the cold heat generated in the desorption section 22 is recovered by another heat medium, the temperature of the heat medium decreases.

[0038] 1-3 can also be applied to the heat pump cycle of the non-circulation type refrigeration system 1. The operation of the non-circulation type refrigeration system 1 will be described later with a specific example.

[0039] The circulating and non-circulating refrigeration systems 1 have a plurality of operating modes with different operating differential pressures. The operating differential pressure is the difference between the pressure of a high-pressure refrigerant, which is a refrigerant in a high-pressure region, and the pressure of a low-pressure refrigerant, which is a refrigerant in a low-pressure region, while the refrigeration system 1 is operating. The refrigeration system 1 has, for example, a first operating mode in which the operating differential pressure is a first value, and a second operating mode in which the operating differential pressure is a second value different from the first value. The number of operating modes that the refrigeration system 1 has can be set arbitrarily.

[0040] (3) Detailed configuration (3-1) First embodiment The specific configuration of the circulation type refrigeration device 100 will be described with reference to the drawings.

[0041] (3-1-1) Configuration of the Refrigeration Device 100 As shown in Fig. 4, the refrigeration device 100 of the first embodiment includes a refrigerant flow path 111 through which a refrigerant circulates. The refrigerant flow path 111 has the functions of both the refrigerant circuit 11 and the adsorption circuit 12 of Fig. 1. The adsorbent flows together with the refrigerant through a portion of the refrigerant flow path 111. In other words, in the refrigeration device 100, a mixture of the refrigerant and the adsorbent flows through the refrigerant flow path 111.

[0042] The refrigeration apparatus 100 includes a compressor 131, an expansion mechanism 132, a first adsorption device 133, a second adsorption device 134, a switching mechanism 135, a first fan 136, a second fan 137, a booster 141, and a separator 151. A refrigerant flow path 111 connects the compressor 131, the expansion mechanism 132, the first adsorption device 133, the second adsorption device 134, the switching mechanism 135, the first fan 136, the second fan 137, the booster 141, and the separator 151. The compressor 131 corresponds to the compressor 31 in FIG. 1. The booster 141 corresponds to the booster 41 in FIG. 1. The expansion mechanism 132 has the functions of both the expansion mechanism 32 and the decompressor 42 in FIG. 1. The expansion mechanism 132 has a function of adjusting the opening degree of a passage through which a fluid passes. The expansion mechanism 132 is, for example, an electronic expansion valve.

[0043] The switching mechanism 135 switches the flow direction of the mixture of refrigerant and adsorbent circulating within the refrigerant flow path 111. The switching mechanism 135 is, for example, a four-way switching valve. The switching mechanism 135 is configured to be able to switch the refrigerant flow path 111 between a first state in which the flow direction is indicated by the solid line in FIG. 4 and a second state in which the flow direction is indicated by the dashed line in FIG. 4. When the refrigerant flow path 111 is in the first state, the discharge sides of the compressor 131 and the booster 141 are connected to the first adsorber 133, and the suction sides of the compressor 131 and the booster 141 are connected to the second adsorber 134. When the refrigerant flow path 111 is in the second state, the discharge sides of the compressor 131 and the booster 141 are connected to the second adsorber 134, and the suction sides of the compressor 131 and the booster 141 are connected to the first adsorber 133.

[0044] The separator 151 is provided between the suction sides of the compressor 131 and the booster 141 and the switching mechanism 135 .

[0045] The separator 151 separates the mixture of the refrigerant and the adsorbent flowing through the refrigerant flow path 111 into the refrigerant and the adsorbent. The separator 151 is, for example, a centrifugal separator that separates the refrigerant from the adsorbent. The refrigerant separated by the separator 151 is compressed in the compressor 131. The adsorbent separated by the separator 151 is pressurized in the booster 141. As shown in FIG. 4 , the adsorbent pressurized in the booster 141 merges with the refrigerant compressed in the compressor 131. After merging, the refrigerant and the adsorbent are sent to the switching mechanism 135. In this way, the refrigerant flow path 111 branches at the separator 151 and merges between the compressor 131 and the booster 141 and the switching mechanism 135.

[0046] In the first adsorption device 133, the refrigerant is adsorbed onto the adsorbent while the refrigerant flow path 111 is in the first state, and the refrigerant is desorbed from the adsorbent while the refrigerant flow path 111 is in the second state. In the second adsorption device 134, the refrigerant is desorbed from the adsorbent while the refrigerant flow path 111 is in the first state, and the refrigerant is adsorbed onto the adsorbent while the refrigerant flow path 111 is in the second state.

[0047] While the refrigerant flow path 111 is in the first state, adsorption heat is generated in the first adsorption device 133, and desorption heat is generated in the second adsorption device 134. While the refrigerant flow path 111 is in the second state, desorption heat is generated in the first adsorption device 133, and adsorption heat is generated in the second adsorption device 134. The adsorption heat is hot heat generated when the adsorbent adsorbs the refrigerant. The desorption heat is cold heat generated when the adsorbent desorbs the refrigerant.

[0048] The heat of adsorption or desorption generated in the first adsorption device 133 and the second adsorption device 134 is recovered by the air surrounding the first adsorption device 133 and the second adsorption device 134. Therefore, the air surrounding the first adsorption device 133 and the second adsorption device 134 is heated by the heat of adsorption or cooled by the heat of desorption. The first fan 136 sends the air heated or cooled in the first adsorption device 133 to a predetermined location. The second fan 137 sends the air heated or cooled in the second adsorption device 134 to a predetermined location.

[0049] In this way, in the refrigeration apparatus 100, air heated by the heat of adsorption or air cooled by the heat of cooling is sent to a predetermined location while the mixture of refrigerant and adsorbent circulates within the refrigerant flow path 111. If the refrigeration apparatus 100 is an air conditioner, for example, the first adsorber 133 corresponds to an indoor heat exchanger, and the second adsorber 134 corresponds to an outdoor heat exchanger. In this case, by switching the refrigerant flow path 111 to the first state, the refrigerant is adsorbed by the adsorbent in the first adsorber 133, generating heat of adsorption. The air heated by the heat of adsorption is sent to a predetermined location by the first fan 136.

[0050] The refrigeration apparatus 100 further includes a control unit 105. The control unit 105 controls the operation of each component of the refrigeration apparatus 100. Here, a processor is shown as an example of the control unit 105. The processor is made up of various computing devices such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), an FPGA (Field-Programmable Gate Array), and a GPU (Graphics Processing Unit). The processor reads various programs of the apparatus into memory and executes them. The processor loads programs stored in memory into a working area of ​​the memory, executes them, and realizes functions that meet a predetermined purpose by controlling each component through the execution of the programs.

[0051] As shown in FIG. 5, the control unit 105 controls the compressor 131, the expansion mechanism 132, the switching mechanism 135, the first fan 136, the second fan 137, and the booster 141. The control unit 105 controls the rotation speed of the compressor 131. The control unit 105 controls the timing to start the compressor 131 and the timing to stop the compressor 131. The control unit 105 controls the opening degree of the expansion mechanism 132. The control unit 105 controls the switching mechanism 135 to switch the refrigerant flow path 111 between a first state and a second state. The control unit 105 controls the rotation speeds of the first fan 136 and the second fan 137. The control unit 105 controls the capacity of the booster 141.

[0052] (3-1-2) Operation of the Refrigeration Device 100 When the refrigerant flow path 111 is in the first state, the discharge side of the compressor 131 is connected to the first adsorber 133 (first heat recovery section) to create a high-pressure state inside the first adsorber 133, and the suction side of the compressor 131 is connected to the second adsorber 134 (second heat recovery section) to create a low-pressure state inside the second adsorber 134. Therefore, the adsorbent flowing inside the refrigerant flow path 111 adsorbs the refrigerant in the first adsorber 133 (first heat recovery section) and desorbs the refrigerant in the second adsorber 134 (second heat recovery section).

[0053] When the refrigerant flow path 111 is in the second state, the suction side of the compressor 131 is connected to the first adsorber 133 (second heat recovery section) to create a low-pressure state inside the first adsorber 133, and the discharge side of the compressor 131 is connected to the second adsorber 134 (first heat recovery section) to create a high-pressure state inside the second adsorber 134. Therefore, the adsorbent flowing inside the refrigerant flow path 111 adsorbs the refrigerant in the second adsorber 134 (first heat recovery section) and desorbs the refrigerant in the first adsorber 133 (second heat recovery section).

[0054] (3-1-3) Control of the refrigeration device 100 The control unit 105 changes the operation mode of the refrigeration apparatus 100. The control unit 105 adjusts the operating differential pressure by controlling at least one of the compressor 131 and the expansion mechanism 132, thereby changing the operation mode of the refrigeration apparatus 100. The control unit 105 acquires the operating differential pressure based on detection values ​​of pressure sensors provided in the high-pressure region and the low-pressure region of the refrigerant flow path 111. The control unit 105 may estimate the operating differential pressure based on detection values ​​of temperature sensors provided in the high-pressure region and the low-pressure region of the refrigerant flow path 111. The pressure sensors or temperature sensors are provided, for example, in spaces in the first adsorption device 133 and the second adsorption device 134 through which the refrigerant flows.

[0055] When the control unit 105 controls the expansion mechanism 132, it adjusts the operating differential pressure by changing the aperture of the expansion mechanism 132 while the refrigeration apparatus 100 is operating. When the control unit 105 increases the aperture of the expansion mechanism 132, the flow rate of the refrigerant passing through the expansion mechanism 132 increases. As a result, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 111 decreases, and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 111 increases, thereby reducing the operating differential pressure. When the control unit 105 decreases the aperture of the expansion mechanism 132, the flow rate of the refrigerant passing through the expansion mechanism 132 decreases. As a result, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 111 increases, and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 111 decreases, thereby increasing the operating differential pressure.

[0056] When controlling the compressor 131, the control unit 105 adjusts the operating differential pressure by controlling at least one of the timing to start the compressor 131 and the timing to stop the compressor 131. When the control unit 105 stops the compressor 131 while the refrigeration apparatus 100 is operating, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 111 decreases, and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 111 increases, thereby reducing the operating differential pressure. When the control unit 105 starts the compressor 131 while the refrigeration apparatus 100 is stopped, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 111 increases, and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 111 decreases, thereby increasing the operating differential pressure. The control unit 105 may adjust the operating differential pressure, for example, by adjusting the ratio between the operating time (period during which the rotation speed is not zero) and the stop time (period during which the rotation speed is zero) of the compressor 131 in a predetermined period (one heat pump cycle).

[0057] When controlling the compressor 131, the control unit 105 adjusts the operating differential pressure by changing the rotation speed of the compressor 131 without stopping the compressor 131. When the control unit 105 increases the rotation speed of the compressor 131, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 111 increases and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 111 decreases, and the operating differential pressure increases. When the control unit 105 decreases the rotation speed of the compressor 131, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 111 decreases and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 111 increases, and the operating differential pressure decreases.

[0058] The control unit 105 adjusts the operating differential pressure, for example, by controlling at least one of the compressor 131 and the expansion mechanism 132 in accordance with the control parameter. If the refrigeration apparatus 100 is an air conditioner, the control parameter is, for example, the temperature of a space to be air-conditioned. The control unit 105 may automatically acquire the control parameter based on a detection value from a sensor or the like. The control unit 105 may also acquire the control parameter input from outside.

[0059] The control unit 105 may acquire a target value for the operating differential pressure, and adjust the operating differential pressure by controlling at least one of the compressor 131 and the expansion mechanism 132 so that the operating differential pressure approaches the target value.

[0060] (3-1-4) Features In the refrigeration apparatus 100, the capacity of the refrigeration apparatus 100 can be changed by adjusting the amount of refrigerant adsorbed onto the adsorbent or the amount of refrigerant desorbed from the adsorbent. In the refrigeration apparatus 100 of this embodiment, the control unit 105 controls at least one of the compressor 131 and the expansion mechanism 132 to adjust the operating differential pressure, which is the difference between the pressure in the high-pressure region and the pressure in the low-pressure region of the refrigerant flow path 111. By adjusting the operating differential pressure, the control unit 105 can change the amount of refrigerant adsorbed or desorbed, thereby adjusting the capacity of the refrigeration apparatus 100. By increasing the operating differential pressure, the control unit 105 can increase the amount of refrigerant adsorbed or desorbed, thereby increasing the capacity of the refrigeration apparatus 100. By decreasing the operating differential pressure, the control unit 105 can decrease the amount of refrigerant adsorbed or desorbed, thereby decreasing the capacity of the refrigeration apparatus 100.

[0061] The refrigeration apparatus 100 has a plurality of operation modes. A different operating differential pressure is set for each operation mode. Therefore, the control unit 105 can change the operating differential pressure by changing the operation mode, thereby adjusting the capacity of the refrigeration apparatus 100.

[0062] (3-2) Second embodiment The specific configuration of the non-circulating refrigeration device 200 will be described with reference to the drawings.

[0063] (3-2-1) Configuration of the Refrigeration Device 200 As shown in Fig. 6, a refrigeration apparatus 200 of the second embodiment includes a heat source side circuit 201 and a utilization side circuit 202. The heat source side circuit 201 has a refrigerant flow path 211 through which a refrigerant flows. The utilization side circuit 202 has a heat medium flow path 212 through which a heat medium flows. In Fig. 6, the refrigerant flow path 211 is depicted with a thick line. The refrigerant flow path 211 corresponds to the refrigerant circuit 11 in Fig. 1. The refrigeration apparatus 200 does not have a circuit through which an adsorbent circulates, which corresponds to the adsorption circuit 12 in Fig. 1. In the refrigeration apparatus 200, the adsorbent is provided in the refrigerant flow path 211. The heat medium flowing through the heat medium flow path 212 is selected from the group consisting of, for example, water, brine, and air. Brine is a liquid with a freezing point of 0°C or lower.

[0064] The refrigeration device 200 further includes a control unit 205. As shown in FIG. 7, the control unit 205 controls the operation of each element constituting the heat source side circuit 201 and the utilization side circuit 202. Here, a processor is illustrated as an example of the control unit 205. The processor is made up of various arithmetic devices such as a central processing unit (CPU), a digital signal processor (DSP), a field-programmable gate array (FPGA), and a graphics processing unit (GPU). The processor reads various programs of the device into memory and executes them. The processor loads the programs stored in memory into a working area of ​​the memory, executes them, and realizes functions that meet a predetermined purpose by controlling each component, etc. through the execution of the programs.

[0065] (3-2-1-1) Heat source side circuit 201 The heat source side circuit 201 constitutes a refrigeration cycle that functions as a heat pump that utilizes heat generated when the refrigerant is adsorbed to or desorbed from the adsorbent.

[0066] The heat source side circuit 201 has a compressor 231, a first adsorption device 221, a second adsorption device 222, and a switching mechanism 235. The refrigerant flow path 211 connects the compressor 231, the first adsorption device 221, the second adsorption device 222, and the switching mechanism 235. The compressor 231 corresponds to the compressor 31 in FIG. 1 .

[0067] The compressor 231 compresses the refrigerant flowing through the refrigerant flow path 211. The compressor 231 draws in low-pressure refrigerant from the refrigerant flow path 211, compresses it, and discharges it to the refrigerant flow path 211 as high-pressure refrigerant. The low-pressure refrigerant is the refrigerant in the refrigerant flow path 211 before being compressed by the compressor 231. The high-pressure refrigerant is the refrigerant in the refrigerant flow path 211 after being compressed by the compressor 231. During operation of the compressor 231, lubricating oil sealed in the refrigerant flow path 211 is supplied to the sliding parts of the compressor 231. A portion of the lubricating oil is accumulated in the bottom of the casing of the compressor 231.

[0068] In the first adsorption device 221 and the second adsorption device 222, the heat of adsorption or desorption heat is recovered by the heat medium flowing through the heat medium flow path 212. The heat of adsorption is hot heat generated when the adsorbent adsorbs the refrigerant. The heat of desorption is cold heat generated when the adsorbent desorbs the refrigerant.

[0069] The first adsorption device 221 and the second adsorption device 222 are connected to a switching mechanism 235 in the refrigerant flow path 211 .

[0070] The switching mechanism 235 switches the flow direction of the refrigerant flowing through the refrigerant flow path 211. The switching mechanism 235 is, for example, a four-way switching valve. The switching mechanism 235 is configured to be able to switch the refrigerant flow path 211 between a first state in which the flow direction is indicated by the solid line in FIG. 6 and a second state in which the flow direction is indicated by the dashed line in FIG. 6. In the first state, the discharge side of the compressor 231 is connected to the first adsorption device 221, and the suction side of the compressor 231 is connected to the second adsorption device 222. In the second state, the discharge side of the compressor 231 is connected to the second adsorption device 222, and the suction side of the compressor 231 is connected to the first adsorption device 221.

[0071] The control unit 205 controls the compressor 231 and the switching mechanism 235. The control unit 205 controls the rotation speed of the compressor 231. The control unit 205 controls the timing to start the compressor 231 and the timing to stop the compressor 231. The control unit 205 controls the switching mechanism 235 to switch the refrigerant flow path 211 between the first state and the second state.

[0072] (3-2-1-2) User side circuit 202 The utilization-side circuit 202 functions as a heat transfer means for utilizing, via a heat medium, the heat generated in the heat source-side circuit 201. The heat medium flowing through the heat medium flow path 212 transfers the heat of adsorption or desorption recovered in the first adsorption device 221 or the second adsorption device 222 to a predetermined location.

[0073] The utilization side circuit 202 includes a first fluid pump 241, a utilization side heat exchanger 242, a first fan 243, a first adsorption device 221, a second fluid pump 251, a heat source side heat exchanger 252, a second fan 253, a second adsorption device 222, and flow path changing units 256-259. The heat medium flow path 212 connects the first fluid pump 241, the utilization side heat exchanger 242, the first adsorption device 221, the second fluid pump 251, the heat source side heat exchanger 252, the second adsorption device 222, and the flow path changing units 256-259.

[0074] The first fluid pump 241 sends the heat medium to the use-side heat exchanger 242. The use-side heat exchanger 242 exchanges heat between the heat medium and air. The first fan 243 generates a flow of air passing through the use-side heat exchanger 242 so that heat exchange occurs in the use-side heat exchanger 242.

[0075] The second fluid pump 251 sends the heat medium to the heat source side heat exchanger 252. The heat source side heat exchanger 252 exchanges heat between the heat medium and air. The second fan 253 generates a flow of air passing through the heat source side heat exchanger 252 so that heat exchange occurs in the heat source side heat exchanger 252.

[0076] The flow path changing units 256-259 change the connection state of the heat medium flow path 212 to change the flow path through which the heat medium flows. The flow path changing units 256-259 are, for example, three-way switching valves. The flow path changing units 256-259 are configured to be able to switch the heat medium flow path 212 between a third connection state indicated by the solid line in Fig. 6 and a fourth connection state indicated by the dashed line in Fig. 6.

[0077] The heat medium flow path 212 has two independent flow paths, a first circulation path and a second circulation path, in each of the third and fourth states. The heat medium circulates through both the first and second circulation paths. In Fig. 6, the flow direction of the heat medium in the third state is indicated by a solid line, and the flow direction of the heat medium in the fourth state is indicated by a dashed line.

[0078] In the third state, the first circulation flow path connects the first fluid pump 241, the use-side heat exchanger 242, the flow path changing unit 256, the first adsorption device 221, and the flow path changing unit 257. In the third state, the second circulation flow path connects the second fluid pump 251, the heat-source-side heat exchanger 252, the flow path changing unit 258, the second adsorption device 222, and the flow path changing unit 259.

[0079] In the fourth state, the first circulation flow path connects the first fluid pump 241, the use-side heat exchanger 242, the flow path changing unit 256, the second adsorption device 222, and the flow path changing unit 257. In the fourth state, the second circulation flow path connects the second fluid pump 251, the heat-source-side heat exchanger 252, the flow path changing unit 258, the first adsorption device 221, and the flow path changing unit 259.

[0080] The control unit 205 controls the first fluid pump 241, the first fan 243, the second fluid pump 251, the second fan 253, and the flow path changing units 256-259. The control unit 205 controls the capacity of the first fluid pump 241 and the second fluid pump 251. The control unit 205 controls the rotation speed of the first fan 243 and the second fan 253. The control unit 205 controls the flow path changing units 256-259 to switch the heat medium flow path 212 between the third state and the fourth state.

[0081] (3-2-1-3) First adsorption device 221 and second adsorption device 222 The first adsorption device 221 and the second adsorption device 222 each include a heat recovery member, an adsorbent, and a casing. The first adsorption device 221 and the second adsorption device 222 each have a first space through which a refrigerant flows and a second space through which a heat medium flows. The first space is a part of the refrigerant flow path 211. The second space is a part of the heat medium flow path 212. The first space and the second space do not communicate with each other.

[0082] The heat recovery member separates the first space from the second space. The adsorbent is provided in the first space. The adsorbent adsorbs and desorbs the refrigerant in the first space in response to changes in the pressure of the refrigerant in the first space. The adsorbent is supported on a first surface, which is a surface of the heat recovery member.

[0083] In the refrigeration device 200, the metal-organic framework is used as an adsorbent for adsorbing and desorbing the refrigerant flowing through the refrigerant flow path 211. The adsorbent used in the refrigeration device 200 is, for example, a powder of the metal-organic framework or a molded product of the metal-organic framework. In this case, the adsorbent is supported on the first surface by adhering a mixture of the adsorbent and a binder to the first surface. Examples of the binder include an acrylic resin, a polyester resin, a polyolefin resin, and a polyurethane resin.

[0084] The heat recovery member is a cross-fin type. As shown in FIG. 8, the heat recovery member includes a plurality of fins 261 and heat transfer tubes 262. Each heat transfer tube 262 has a plurality of straight tube portions 262a extending linearly and a folded portion 262b connecting two straight tube portions 262a. In FIG. 8, the thickness of the heat transfer tube 262 is omitted. Each of the fins 261 has through holes in its thickness direction through which the straight tube portions 262a of the heat transfer tube 262 penetrate. The fins 261 are stacked around the straight tube portions 262a of the heat transfer tube 262 at predetermined intervals along the direction in which the straight tube portions 262a extend. A first end 262c and a second end 262d of the heat transfer tube 262 are connected to the heat medium flow path 212. The fins 261 and the heat transfer tubes 262 are housed in a casing 263. The casing 263 has an inlet 263 a connected to the refrigerant flow path 211 .

[0085] The refrigerant flowing through the refrigerant flow path 211 flows into the casing 263 through the inlet 263a, and flows out of the casing 263 through the inlet 263a. The heat medium flowing through the heat medium flow path 212 flows into the heat transfer tube 262 through the first end 262c, and flows out of the heat transfer tube 262 through the second end 262d.

[0086] As shown in FIG. 8 , the first space 264a through which the refrigerant flows is a space inside the casing 263 and outside the heat transfer tube 262. The second space 264b through which the heat medium flows is a space inside the casing 263 and inside the heat transfer tube 262. The first surface 282, on which the adsorbent 281 that adsorbs and desorbs the refrigerant is supported, includes at least a portion of the outer surfaces of the multiple fins 261 and the heat transfer tube 262. The first surface 282 is, for example, the surfaces of the multiple fins 261 and the outer surface of the heat transfer tube 262. The first surface 282 is in contact with the first space 264a. Therefore, the refrigerant in the first space 264a comes into contact with the adsorbent 281 supported on the first surface 282.

[0087] The adsorbent 281 adsorbs the refrigerant in the first space 264a when the pressure of the refrigerant in the first space 264a is equal to or higher than the adsorption pressure. The adsorbent 281 desorbs the refrigerant in the first space 264a when the pressure of the refrigerant in the first space 264a is equal to or lower than the desorption pressure. The adsorption pressure is the minimum value of the range of pressures at which the adsorbent 281 can adsorb the refrigerant at the temperature of the first space 264a. The desorption pressure is the maximum value of the range of pressures at which the adsorbent 281 can desorb the refrigerant at the temperature of the first space 264a. The adsorption pressure and desorption pressure differ depending on the type of adsorbent 281 and the refrigerant.

[0088] (3-2-2) Operation of the Refrigeration Device 200 The operation of the refrigeration device 200 will be described assuming that the refrigeration device 200 is an air conditioner. In this case, the utilization-side heat exchanger 242 corresponds to an indoor heat exchanger, and the heat-source-side heat exchanger 252 corresponds to an outdoor heat exchanger.

[0089] The adsorbent 281 of the first adsorption device 221 and the second adsorption device 222 adsorbs and desorbs the refrigerant in the refrigerant flow path 211. The adsorbent 281 adsorbs the refrigerant when in contact with the high-pressure refrigerant in the first space 264a. The adsorbent 281 desorbs the refrigerant when in contact with the low-pressure refrigerant in the first space 264a.

[0090] When the refrigerant flow path 211 is in the first state, the discharge side of the compressor 231 is connected to the first adsorber 221 (first heat recovery unit) to create a high-pressure state inside the first adsorber 221, and the suction side of the compressor 231 is connected to the second adsorber 222 (second heat recovery unit) to create a low-pressure state inside the second adsorber 222. When the inside of the first adsorber 221 is in a high-pressure state, the adsorbent 281 of the first adsorber 221 is in contact with a high-pressure refrigerant in the first space 264a. When the inside of the second adsorber 222 is in a low-pressure state, the adsorbent 281 of the second adsorber 222 is in contact with a low-pressure refrigerant in the first space 264a. Therefore, the adsorbent 281 in the first adsorber 221 adsorbs the refrigerant, and the adsorbent 281 in the second adsorber 222 desorbs the refrigerant.

[0091] When the refrigerant flow path 211 is in the second state, the suction side of the compressor 231 is connected to the first adsorber 221 (second heat recovery unit) to create a low-pressure state inside the first adsorber 221, and the discharge side of the compressor 231 is connected to the second adsorber 222 (first heat recovery unit) to create a high-pressure state inside the second adsorber 222. When the inside of the first adsorber 221 is in a low-pressure state, the adsorbent 281 of the first adsorber 221 is in contact with the low-pressure refrigerant in the first space 264a. When the inside of the second adsorber 222 is in a high-pressure state, the adsorbent 281 of the second adsorber 222 is in contact with the high-pressure refrigerant in the first space 264a. Therefore, the adsorbent 281 in the second adsorber 222 adsorbs the refrigerant, and the adsorbent 281 in the first adsorber 221 desorbs the refrigerant.

[0092] The following describes changes in the adsorption amount, which is the amount of refrigerant adsorbed by the adsorbent 281, when the refrigerant flow path 211 is in the first state. When the switching mechanism 235 switches from the second state to the first state, the adsorption amount of the adsorbent 281 in the first adsorption device 221 is the first adsorption amount, and the adsorption amount of the adsorbent 281 in the second adsorption device 222 is the second adsorption amount. The second adsorption amount is larger than the first adsorption amount. The second adsorption amount is the maximum amount of refrigerant that can be adsorbed by the adsorbent 281. The second adsorption amount includes not only the theoretical maximum amount but also an amount that can change depending on the time the high-pressure pressure or high-pressure state is maintained. The pressure of the high-pressure refrigerant is equal to or higher than the adsorption pressure, and the pressure of the low-pressure refrigerant is equal to or lower than the desorption pressure.

[0093] When the refrigerant flow path 211 is in the first state, the adsorbent 281 in the first adsorbent 221 contacts a high-pressure refrigerant, and the adsorbent 281 in the second adsorbent 222 contacts a low-pressure refrigerant. In the first adsorbent 221, the adsorbent 281 gradually adsorbs the refrigerant, releasing heat in the process. In the second adsorbent 222, the adsorbent 281 gradually desorbs the refrigerant, absorbing heat in the process. Therefore, the adsorption amount of the adsorbent 281 in the first adsorbent 221 increases from the first adsorption amount to the second adsorption amount, and the adsorption amount of the adsorbent 281 in the second adsorbent 222 decreases from the second adsorption amount to the first adsorption amount.

[0094] The following describes a change in the adsorption amount, which is the amount of refrigerant adsorbed by the adsorbent 281, when the refrigerant flow path 211 is in the second state. In the state when the switching mechanism 235 switches from the first state to the second state, the adsorption amount of the adsorbent 281 in the first adsorption device 221 is the second adsorption amount, and the adsorption amount of the adsorbent 281 in the second adsorption device 222 is the first adsorption amount.

[0095] When the refrigerant flow path 211 is in the second state, the adsorbent 281 in the first adsorbent 221 contacts the low-pressure refrigerant, and the adsorbent 281 in the second adsorbent 222 contacts the high-pressure refrigerant. In the first adsorbent 221, the adsorbent 281 gradually desorbs the refrigerant, absorbing heat in the process. In the second adsorbent 222, the adsorbent 281 gradually adsorbs the refrigerant, releasing heat in the process. Therefore, the adsorption amount of the adsorbent 281 in the first adsorbent 221 decreases from the second adsorption amount to the first adsorption amount, and the adsorption amount of the adsorbent 281 in the second adsorbent 222 increases from the first adsorption amount to the second adsorption amount.

[0096] When the refrigerant flow path 211 is in the first state and the heat medium flow path 212 is in the third state, in the first adsorption device 221, hot heat generated in the process in which the adsorbent 281 adsorbs the refrigerant in the first space 264a is recovered by the heat medium in the second space 264b. On the other hand, in the second adsorption device 222, cold heat generated in the process in which the adsorbent 281 desorbs the refrigerant adsorbed by the adsorbent 281 is recovered by the heat medium in the second space 264b. Therefore, in the first adsorption device 221, hot heat is recovered by the heat medium flowing through the first circulation flow path, and in the second adsorption device 222, cold heat is recovered by the heat medium flowing through the second circulation flow path.

[0097] Thereafter, when the adsorption amount of the adsorbent 281 in the first adsorption device 221 reaches the second adsorption amount, it becomes difficult for the adsorbent 281 in the first adsorption device 221 to adsorb the refrigerant. When this state is reached, the refrigerant flow path 211 is switched from the first state to the second state, and the heat medium flow path 212 is switched from the third state to the fourth state.

[0098] When the refrigerant flow path 211 is in the second state and the heat medium flow path 212 is in the fourth state, in the second adsorption device 222, hot heat generated in the process of the adsorbent 281 adsorbing the refrigerant in the first space 264a is recovered by the heat medium in the second space 264b. On the other hand, in the first adsorption device 221, cold heat generated in the process of the adsorbent 281 desorbing the refrigerant adsorbed by the adsorbent 281 is recovered by the heat medium in the second space 264b. Therefore, in the first adsorption device 221, cold heat is recovered by the heat medium flowing through the second circulation flow path, and in the second adsorption device 222, hot heat is recovered by the heat medium flowing through the first circulation flow path.

[0099] Thereafter, when the adsorption amount of the adsorbent 281 in the second adsorption device 222 reaches the second adsorption amount, it becomes difficult for the adsorbent 281 in the second adsorption device 222 to adsorb the refrigerant. When this state is reached, the refrigerant flow path 211 is switched from the second state to the first state, and the heat medium flow path 212 is switched from the fourth state to the third state.

[0100] As described above, by alternately switching the refrigerant flow path 211 between the first state and the second state, it is possible to continuously adsorb or desorb the refrigerant to the adsorbent 281 in either the first adsorber 221 or the second adsorber 222. By alternately switching the heat medium flow path 212 between the third state and the fourth state in accordance with the switching between the first state and the second state, it is possible to continuously collect, by the heat medium flowing through the first circulation flow path, the hot heat generated when the adsorbent 281 adsorbs the refrigerant. Similarly, by alternately switching the heat medium flow path 212 between the third state and the fourth state in accordance with the switching between the first state and the second state, it is possible to continuously collect, by the heat medium flowing through the second circulation flow path, the cold heat generated when the adsorbent 281 desorbs the refrigerant.

[0101] Therefore, the refrigeration device 200 can continue to supply the heat medium heated by the hot heat recovered in the first adsorption device 221 and the second adsorption device 222 to the use-side heat exchanger 242 connected to the first circulation flow path. The air that has exchanged heat with the heat medium in the use-side heat exchanger 242 is sent to a predetermined location by the first fan 243.

[0102] Furthermore, when the refrigerant flow path 211 is in the first state and the heat medium flow path 212 is in the fourth state, the first adsorber 221 recovers hot heat to the heat medium flowing through the second circulation flow path, and the second adsorber 222 recovers cold heat to the heat medium flowing through the first circulation flow path. When the refrigerant flow path 211 is in the second state and the heat medium flow path 212 is in the third state, the first adsorber 221 recovers cold heat to the heat medium flowing through the first circulation flow path, and the second adsorber 222 recovers hot heat to the heat medium flowing through the second circulation flow path. Therefore, by alternately switching the heat medium flow path 212 between the fourth state and the third state in accordance with the switching between the first state and the second state, it is possible to continuously recover cold heat generated when the adsorbent 281 desorbs the refrigerant by the heat medium flowing through the first circulation flow path. In this case, the refrigeration device 200 can continue to supply the heat medium cooled by the cold energy recovered in the first adsorption device 221 and the second adsorption device 222 to the use-side heat exchanger 242 connected to the first circulation flow path.

[0103] (3-2-3) Control of the Refrigeration Device 200 The control unit 205 changes the operation mode of the refrigeration apparatus 200. The control unit 205 controls the compressor 231 to adjust the operating differential pressure and change the operation mode of the refrigeration apparatus 200. The control unit 205 acquires the operating differential pressure based on detection values ​​of pressure sensors provided in the high-pressure region and the low-pressure region of the refrigerant flow path 211. The pressure sensors are provided so as to detect, for example, the pressures of the inlets 263a of the casings 263 of the first adsorption device 221 and the second adsorption device 222 or the pressures of the first spaces 264a of the first adsorption device 221 and the second adsorption device 222. The control unit 205 may estimate the operating differential pressure based on detection values ​​of temperature sensors provided in the high-pressure region and the low-pressure region of the refrigerant flow path 211, respectively. The temperature sensor is provided so as to detect the temperature of the inlet 263a of the casing 263 of the first adsorption device 221 and the second adsorption device 222, or the temperature of the first space 264a of the first adsorption device 221 and the second adsorption device 222, for example.

[0104] The control unit 205 adjusts the operating differential pressure by controlling at least one of the timing to start the compressor 231 and the timing to stop the compressor 231. When the control unit 205 stops the compressor 231 while the refrigeration device 200 is operating, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 211 decreases, and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 211 increases, thereby reducing the operating differential pressure. When the control unit 205 starts the compressor 231 while the refrigeration device 200 is stopped, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 211 increases, and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 211 decreases, thereby increasing the operating differential pressure. The control unit 205 may adjust the operating differential pressure by, for example, adjusting the ratio between the operating time (period during which the rotation speed is not zero) and the stop time (period during which the rotation speed is zero) of the compressor 231 in a predetermined period (one heat pump cycle).

[0105] The control unit 205 adjusts the operating differential pressure by changing the rotation speed of the compressor 231 without stopping the compressor 231. When the control unit 205 increases the rotation speed of the compressor 231, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 211 increases and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 211 decreases, and the operating differential pressure increases. When the control unit 205 decreases the rotation speed of the compressor 231, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 211 decreases and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 211 increases, and the operating differential pressure decreases.

[0106] The control unit 205 adjusts the operating differential pressure, for example, by controlling the compressor 231 in accordance with the control parameter. If the refrigeration device 200 is an air conditioner, the control parameter is, for example, the temperature of a space to be air-conditioned. The control unit 205 may automatically acquire the control parameter based on a detection value from a sensor or the like. The control unit 205 may also acquire the control parameter input from outside.

[0107] The control unit 205 may acquire a target value for the operating differential pressure, and control the compressor 231 to adjust the operating differential pressure so that the operating differential pressure approaches the target value.

[0108] (3-2-4) Features In the refrigeration apparatus 200, the capacity of the refrigeration apparatus 200 can be changed by adjusting the amount of refrigerant adsorbed onto the adsorbent or the amount of refrigerant desorbed from the adsorbent. In the refrigeration apparatus 200 of this embodiment, the control unit 205 controls the compressor 231 to adjust the operating differential pressure, which is the difference between the pressure in the high-pressure region and the pressure in the low-pressure region of the refrigerant flow path 211. By adjusting the operating differential pressure, the control unit 205 can change the amount of refrigerant adsorbed or desorbed, thereby adjusting the capacity of the refrigeration apparatus 200. By increasing the operating differential pressure, the control unit 205 can increase the amount of refrigerant adsorbed or desorbed, thereby increasing the capacity of the refrigeration apparatus 200. By decreasing the operating differential pressure, the control unit 205 can decrease the amount of refrigerant adsorbed or desorbed, thereby decreasing the capacity of the refrigeration apparatus 200.

[0109] Furthermore, the refrigeration device 200 has a plurality of operation modes. A different operating differential pressure is set for each operation mode. Therefore, the control unit 205 can change the operating differential pressure by changing the operation mode, thereby adjusting the capacity of the refrigeration device 200.

[0110] (4) Variations (4-1) Variation A (4-1-1) Configuration of the Refrigeration Device 200 The basic configuration and operation of the refrigeration device 200 of this modified example are the same as those of the refrigeration device 200 of the second embodiment. The main difference between the refrigeration device 200 of this modified example and the refrigeration device 200 of the second embodiment is the heat source side circuit 201.

[0111] 9 , a bypass flow path 291 through which the refrigerant flows is further formed in the heat source side circuit 201. The bypass flow path 291 connects the first adsorption device 221 and the second adsorption device 222 without passing through the compressor 231. The bypass flow path 291 connects, in the refrigerant flow path 211, the flow path between the first adsorption device 221 and the switching mechanism 235 and the flow path between the second adsorption device 222 and the switching mechanism 235.

[0112] The heat source side circuit 201 further includes a bypass valve 292. The bypass valve 292 is, for example, a solenoid valve. The bypass valve 292 is attached to a pipe in the bypass flow path 291 through which the refrigerant flows.

[0113] 10, the control unit 205 further controls the bypass valve 292. The control unit 205 controls the bypass valve 292 to open or close, thereby allowing or blocking the flow of refrigerant in the bypass flow path 291.

[0114] (4-1-2) Operation of the Refrigeration Device 200 When the refrigerant flow path 211 is in the first state, high-pressure refrigerant is present in the first space 264a of the first adsorption device 221, and low-pressure refrigerant is present in the first space 264a of the second adsorption device 222. When the refrigerant flow path 211 is in the second state, low-pressure refrigerant is present in the first space 264a of the first adsorption device 221, and high-pressure refrigerant is present in the first space 264a of the second adsorption device 222. Therefore, when the refrigerant flow path 211 is in the first state and the second state, the pressure in the first space 264a of the first adsorption device 221 and the pressure in the first space 264a of the second adsorption device 222 are different from each other.

[0115] The bypass valve 292 is closed while hot energy or cold energy is being recovered in the first adsorption device 221 and the second adsorption device 222. The bypass valve 292 is opened when the refrigerant flow path 211 is switched between the first state and the second state. When the bypass valve 292 is opened, the first space 264a of the first adsorption device 221 and the first space 264a of the second adsorption device 222 are connected to each other. This reduces the difference in pressure between the first space 264a of the first adsorption device 221 and the first space 264a of the second adsorption device 222, thereby achieving pressure equalization.

[0116] If the bypass valve 292 is opened and pressure equalization is performed when the refrigerant flow path 211 switches from the first state to the second state, the pressure in the first space 264a of the first adsorption device 221 decreases and the pressure in the first space 264a of the second adsorption device 222 increases. Therefore, after the refrigerant flow path 211 switches to the second state, the time until the pressure in the first space 264a of the first adsorption device 221 reaches the desorption pressure and the time until the pressure in the first space 264a of the second adsorption device 222 reaches the adsorption pressure are shortened.

[0117] If the bypass valve 292 is opened and pressure equalization is performed when the refrigerant flow path 211 switches from the second state to the first state, the pressure in the first space 264a of the first adsorption device 221 increases and the pressure in the first space 264a of the second adsorption device 222 decreases. Therefore, after the refrigerant flow path 211 switches to the first state, the time until the pressure in the first space 264a of the first adsorption device 221 reaches the adsorption pressure and the time until the pressure in the first space 264a of the second adsorption device 222 reaches the desorption pressure are shortened.

[0118] (4-1-3) Control of the refrigeration device 200 The control unit 205 controls at least one of the compressor 231 and the bypass valve 292 to adjust the operating differential pressure and change the operation mode of the refrigeration device 200.

[0119] When controlling the bypass valve 292, the control unit 205 adjusts the operating differential pressure by changing the aperture of the bypass valve 292 while the refrigeration apparatus 200 is operating. When the control unit 205 increases the aperture of the bypass valve 292, the flow rate of the refrigerant passing through the bypass valve 292 increases. As a result, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 211 decreases, and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 211 increases, thereby reducing the operating differential pressure. When the control unit 205 decreases the aperture of the bypass valve 292, the flow rate of the refrigerant passing through the bypass valve 292 decreases. As a result, the pressure of the refrigerant in the high-pressure region of the refrigerant flow path 211 increases, and the pressure of the refrigerant in the low-pressure region of the refrigerant flow path 211 decreases, thereby increasing the operating differential pressure.

[0120] The control unit 205 adjusts the operating differential pressure by, for example, controlling at least one of the compressor 231 and the bypass valve 292 in accordance with the control parameters.

[0121] The control unit 205 may acquire a target value for the operating differential pressure, and adjust the operating differential pressure by controlling at least one of the compressor 231 and the bypass valve 292 so that the operating differential pressure approaches the target value.

[0122] (4-1-4) Features In the refrigeration device 200 of this modified example, the control unit 205 controls at least one of the compressor 231 and the bypass valve 292 to adjust the operating differential pressure, which is the difference between the pressure in the high-pressure region and the pressure in the low-pressure region of the refrigerant flow path 211. The control unit 205 can adjust the capacity of the refrigeration device 200 by adjusting the operating differential pressure.

[0123] (4-2) Variation B (4-2-1) Configuration of the Refrigeration Device 200 The basic configuration and operation of the refrigeration device 200 of this modified example are the same as those of the refrigeration device 200 of the second embodiment. The main difference between the refrigeration device 200 of this modified example and the refrigeration device 200 of the second embodiment is the heat source side circuit 201.

[0124] 11, the heat source side circuit 201 further includes a first pressure vessel 271, a second pressure vessel 272, a first valve 293, and a second valve 294. The first pressure vessel 271, the second pressure vessel 272, the first valve 293, and the second valve 294 are further connected to the refrigerant flow path 211.

[0125] The first pressure vessel 271 is connected to the discharge side of the compressor 231. The first pressure vessel 271 is provided in the refrigerant flow path 211 between the discharge side of the compressor 231 and the switching mechanism 235.

[0126] The second pressure vessel 272 is connected to the suction side of the compressor 231. The second pressure vessel 272 is provided in the refrigerant flow path 211 between the suction side of the compressor 231 and the switching mechanism 235.

[0127] The first pressure vessel 271 and the second pressure vessel 272 are vessels having an inlet and an outlet for the refrigerant. During operation of the refrigeration device 200, the first pressure vessel 271 and the second pressure vessel 272 contain a refrigerant therein that flows through the refrigerant flow path 211. During operation of the refrigeration device 200, the first pressure vessel 271 contains a high-pressure refrigerant therein. During operation of the refrigeration device 200, the second pressure vessel 272 contains a low-pressure refrigerant therein.

[0128] Pressure sensors that detect the internal pressure may be provided inside the first pressure vessel 271 and the second pressure vessel 272. In this case, the control unit 205 acquires the operating differential pressure based on the detected values ​​of the pressure sensors. The operating differential pressure is the difference between the internal pressure of the first pressure vessel 271 and the internal pressure of the second pressure vessel 272. Instead of pressure sensors, temperature sensors that detect the internal temperature may be provided inside the first pressure vessel 271 and the second pressure vessel 272. In this case, the control unit 205 estimates the operating differential pressure based on the detected values ​​of the temperature sensors.

[0129] The first valve 293 and the second valve 294 are, for example, electromagnetic valves. The first valve 293 and the second valve 294 are attached to a pipe in the refrigerant flow path 211 through which the refrigerant flows.

[0130] When the refrigerant flow path 211 is in a first state, the first valve 293 allows or blocks the flow of refrigerant between the first pressure vessel 271 and the first adsorber 221. When the refrigerant flow path 211 is in a second state, the first valve 293 allows or blocks the flow of refrigerant between the first pressure vessel 271 and the second adsorber 222.

[0131] When the refrigerant flow path 211 is in the first state, the second valve 294 allows or blocks the flow of refrigerant between the second pressure vessel 272 and the second adsorber 222. When the refrigerant flow path 211 is in the second state, the second valve 294 allows or blocks the flow of refrigerant between the second pressure vessel 272 and the first adsorber 221.

[0132] 12, the control unit 205 further controls the first valve 293 and the second valve 294. The control unit 205 controls the opening and closing of the first valve 293 and the second valve 294 to allow or block the flow of refrigerant between the first adsorber 221, the second adsorber 222, the first pressure vessel 271, and the second pressure vessel 272.

[0133] (4-2-2) Features While the refrigerant flow path 211 is in the first state, the first pressure vessel 271 communicates with the first adsorber 221, and the second pressure vessel 272 communicates with the second adsorber 222. Therefore, a high-pressure refrigerant is present in the first space 264a of the first adsorber 221, and a low-pressure refrigerant is present in the first space 264a of the second adsorber 222.

[0134] While the refrigerant flow path 211 is in the second state, the first pressure vessel 271 communicates with the second adsorption device 222, and the second pressure vessel 272 communicates with the first adsorption device 221. Therefore, a low-pressure refrigerant is present in the first space 264a of the first adsorption device 221, and a high-pressure refrigerant is present in the first space 264a of the second adsorption device 222.

[0135] The high-pressure refrigerant in the first pressure vessel 271 and the low-pressure refrigerant in the second pressure vessel 272 shorten the first period from the time when the refrigerant flow path 211 switches between the first state and the second state to the time when the pressure in the first space 264a of the first adsorption device 221 and the second adsorption device 222 reaches the adsorption pressure or the desorption pressure.

[0136] When the refrigerant flow path 211 switches from the first state to the second state, during the first period, the pressure in the first space 264a of the second adsorption device 222 is lower than the adsorption pressure, and therefore hot energy is not recovered by the heat medium in the second space 264b. Also, the pressure in the first space 264a of the first adsorption device 221 is higher than the desorption pressure, and therefore cold energy is not recovered by the heat medium in the second space 264b. Therefore, the shorter the first period, the more efficiently hot energy and cold energy are recovered by the heat medium in the first adsorption device 221 and the second adsorption device 222 during operation of the refrigeration device 200.

[0137] Furthermore, by closing the first valve 293 and the second valve 294 for a predetermined time, the control unit 205 can increase the pressure of the refrigerant in the first pressure vessel 271 and decrease the pressure of the refrigerant in the second pressure vessel 272, compared to when the first valve 293 and the second valve 294 are not closed. This shortens the first period, and allows the heat medium to recover hot and cold energy more efficiently.

[0138] Therefore, compared to when the heat source side circuit 201 does not have the first pressure vessel 271 and the second pressure vessel 272, the refrigeration device 200 of this modified example can efficiently recover the hot heat generated when the adsorbent 281 adsorbs the refrigerant, or the cold heat generated when the adsorbent 281 desorbs the refrigerant.

[0139] (4-3) Variation C The adsorbent used in the refrigeration devices 100 and 200 is a metal-organic framework. However, materials other than the metal-organic framework may also be used as the adsorbent. Examples of materials other than the metal-organic framework include activated carbon, zeolite-based materials, silica-based materials, and alumina-based materials.

[0140] Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure as defined in the claims. [Explanation of symbols]

[0141] 100: Refrigeration equipment 105: Control unit 111: refrigerant flow path 131: Compressor 132: Expansion mechanism 133: First adsorber (first heat recovery section, second heat recovery section) 134: Second adsorber (first heat recovery section, second heat recovery section) 200: Refrigeration equipment 205: Control unit 211: Refrigerant flow path 221: First adsorber (first heat recovery section, second heat recovery section) 222: Second adsorber (first heat recovery section, second heat recovery section) 231: Compressor 235: Switching mechanism 271: First pressure vessel 272: Second pressure vessel 281: Adsorbent 291: Bypass flow path 292: Bypass valve [Prior art documents] [Patent documents]

[0142] [Patent Document 1] US Patent Application Publication No. 2023 / 0417459

Claims

1. a refrigerant flow path (111, 211) through which a refrigerant flows; a compressor (131, 231) that draws in and compresses a low-pressure refrigerant and discharges it as a high-pressure refrigerant; an adsorbent (281) that adsorbs and desorbs a refrigerant in response to a change in the pressure of the refrigerant; a first heat recovery section (133, 134, 221, 222) connected to a discharge side of the compressor and configured to recover heat generated when the adsorbent adsorbs the refrigerant; a second heat recovery section (133, 134, 221, 222) connected to the suction side of the compressor and configured to recover cold generated when the adsorbent desorbs the refrigerant; A control unit (105, 205) for changing an operation mode; Equipped with The operation mode is a first operation mode in which a difference between the pressure of the high-pressure refrigerant and the pressure of the low-pressure refrigerant is a first value; a second operating mode in which the difference is a second value different from the first value; Including, A refrigeration device (100, 200).

2. the control unit changes the operation mode by adjusting the difference by changing at least one of a timing to start the compressor and a timing to stop the compressor. The refrigeration system of claim 1.

3. the control unit changes the operation mode by adjusting the difference by changing the rotation speed of the compressor without stopping the compressor. The refrigeration system of claim 1.

4. An expansion mechanism (132) for reducing the pressure of the high-pressure refrigerant to the low-pressure refrigerant, the adsorbent flows through at least a portion of the refrigerant flow path together with the refrigerant circulating through the refrigerant flow path, The control unit changes the operation mode by controlling the expansion mechanism to adjust the difference. The refrigeration device according to any one of claims 1 to 3.

5. Further comprising a switching mechanism (235); one of the first heat recovery unit and the second heat recovery unit is a first adsorption unit having the adsorbent, and the other is a second adsorption unit having the adsorbent, The switching mechanism switches the refrigerant flow path a first state in which a discharge side of the compressor and the first adsorber are connected to each other to create a high-pressure state inside the first adsorber, and a suction side of the compressor and the second adsorber are connected to each other to create a low-pressure state inside the second adsorber; a second state in which the suction side of the compressor and the first adsorber are connected to each other to create a low-pressure state inside the first adsorber, and the discharge side of the compressor and the second adsorber are connected to each other to create a high-pressure state inside the second adsorber; and can be switched between when the refrigerant flow path is in the first state, the first heat recovery unit is the first adsorption device, and the second heat recovery unit is the second adsorption device; When the refrigerant flow path is in the second state, the first heat recovery unit is the second adsorption unit, and the second heat recovery unit is the first adsorption unit. The refrigeration device according to any one of claims 1 to 3.

6. a bypass flow path (291) connecting the first heat recovery unit and the second heat recovery unit without passing through the compressor; a bypass valve (292) provided in the bypass flow path; Furthermore, The control unit changes the operation mode by adjusting the difference by changing the opening degree of the bypass valve.

6. The refrigeration system of claim 5.

7. Further comprising a first pressure vessel (271) and a second pressure vessel (272); the first pressure vessel is provided in the refrigerant flow path between a discharge side of the compressor and the switching mechanism, The second pressure vessel is provided in the refrigerant flow path between the suction side of the compressor and the switching mechanism.

6. The refrigeration system of claim 5.

8. The difference is the difference between the internal pressure of the first pressure vessel and the internal pressure of the second pressure vessel.

8. The refrigeration system of claim 7.

9. The adsorbent includes a metal organic framework including a metal ion and an organic ligand. The refrigeration device according to any one of claims 1 to 3.

10. The refrigerant flowing through the refrigerant flow path is selected from the group consisting of carbon dioxide, hydrocarbon refrigerants, ammonia, and water. The refrigeration device according to any one of claims 1 to 3.

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