Refrigeration device

Abstract

Provided is a refrigeration device (100) in which a refrigerant and an adsorbent circulate, and which comprises a compressor (131), a decompression mechanism (132), a first heat recovery unit (133), a second heat recovery unit (134), and a control unit (105). The first heat recovery unit (133) recovers heat generated when the adsorbent adsorbs the refrigerant. The second heat recovery unit (134) recovers cold generated when the adsorbent desorbs the refrigerant. The first heat recovery unit (133) comprises a first heat transfer pipe (133a) through which a mixture of the refrigerant and the adsorbent passes. The control unit (105) changes at least the rotational rate of the compressor (131) or the aperture of the decompression mechanism (132) so that the area ratio of the refrigerant occupying a first cross-section C of the first heat transfer pipe (133a) is reduced when the capacity of the first heat recovery unit (133) is changed from a first capacity to a second capacity that is greater than the first capacity.

Description

Refrigeration device

[0001] It relates to a refrigeration device.

[0002] Conventionally, as disclosed in Patent Document 1 (U.S. Patent Application Publication No. 2023 / 0417459), a refrigeration device having an adsorption refrigeration cycle that utilizes the heat generated when a refrigerant is adsorbed and desorbed on an adsorbent containing a metal-organic framework has been used. As such a refrigeration device, a circulation-type refrigeration device having a refrigerant flow path through which a mixture of a refrigerant and an adsorbent circulates is known.

[0003] In a circulation-type refrigeration device, it is necessary to recover heat from a mixture of a refrigerant and an adsorbent in a heat recovery unit that recovers the heat generated when the adsorbent adsorbs or desorbs the refrigerant. In order to adjust the capacity of the refrigeration device, it is necessary to adjust the heat recovered in the heat recovery unit.

[0004] The refrigeration device of the first aspect is a refrigeration device in which a refrigerant and an adsorbent circulate. The adsorbent adsorbs and desorbs (desorbs) the refrigerant in response to a change in the pressure of the refrigerant. The refrigeration device includes a compressor, a decompression mechanism, a first heat recovery unit, a second heat recovery unit, and a control unit. The compressor compresses the refrigerant. The decompression mechanism decompresses the refrigerant. The first heat recovery unit recovers the warm heat generated when the adsorbent adsorbs the refrigerant. The second heat recovery unit recovers the cold heat generated when the adsorbent desorbs the refrigerant. The control unit controls the compressor and the decompression mechanism. The first heat recovery unit has a heat transfer tube through which a mixture of the refrigerant and the adsorbent passes. When the control unit changes at least one of the rotation speed of the compressor and the throttle amount of the decompression mechanism to change the capacity of the first heat recovery unit from a first capacity to a second capacity greater than the first capacity, the control unit reduces the area ratio of the refrigerant occupying the first cross section of the heat transfer tube (hereinafter, also referred to as "ratio").

[0005] According to the refrigeration system of the first viewpoint, the control unit changes the ratio when adjusting the capacity of the first heat recovery unit, which recovers the heat generated when the adsorbent adsorbs the refrigerant, to a first capacity and a second capacity by changing at least one of the rotational speed of the compressor and the throttling amount of the pressure reduction mechanism. Here, the control unit decreases the ratio when increasing the capacity. When the ratio decreases, the volume ratio of the adsorbent that has heat inside the heat transfer tube increases. As a result, the adsorbent that has heat comes into contact with the inner surface of the heat transfer tube more easily, and the efficiency of transferring the heat from the adsorbent to the heat transfer tube can be improved. Therefore, the capacity of the circulating refrigeration system can be adjusted efficiently.

[0006] The refrigeration apparatus in the second view is the same as the refrigeration apparatus in the first view, wherein the flow rate of the mixture at the second capacity is slower than the flow rate of the mixture at the first capacity.

[0007] In the second type of refrigeration system, the control unit slows down the flow rate of the mixture of refrigerant and adsorbent when increasing the capacity. When the flow rate slows down, the adsorbent, which is heated, is more likely to come into contact with the inner surface of the heat transfer tube, and the contact time is also increased, thereby improving the efficiency of transferring the heat from the adsorbent to the heat transfer tube. Therefore, the capacity can be adjusted with high efficiency.

[0008] The refrigeration system of the third aspect is a refrigeration system of the first or second aspect, wherein the ratio at the outlet of the heat transfer tube is smaller than the ratio at the inlet of the heat transfer tube.

[0009] In the third type of refrigeration system, the control unit makes the ratio at the outlet of the heat transfer tubes smaller than the ratio at the inlet. As the ratio decreases from the inlet to the outlet of the heat transfer tubes, the proportion of refrigerant within the heat transfer tubes decreases, and the refrigerant is adsorbed onto the adsorbent. Therefore, the adsorbent can generate heat efficiently.

[0010] The refrigeration apparatus of the fourth perspective is a refrigeration apparatus of any of the first, third, or fourth perspectives, wherein the inner surface of the heat transfer tubes has irregularities formed on it.

[0011] In the refrigeration apparatus described in the fourth perspective, since irregularities are formed on the inner surface of the heat transfer tubes, the contact area between the heat-generating adsorbent and the inner surface of the heat transfer tubes can be increased.

[0012] The refrigeration apparatus of the fifth perspective is a refrigeration apparatus of any of the first, second, or fourth perspectives, wherein the depressurization mechanism is a control valve with a variable opening degree, an expander with a variable rotation speed, or a capillary tube.

[0013] As with the refrigeration apparatus in the fifth aspect, a pressure reduction mechanism may be used, such as a control valve with a variable opening degree, an expander with a variable rotation speed, or a capillary tube.

[0014] The refrigeration apparatus of the sixth aspect is a refrigeration apparatus of any of the first to fifth aspects, wherein the adsorbent includes a metal-organic structure containing metal ions and an organic ligand.

[0015] As in the refrigeration apparatus described in the sixth aspect, metal-organic structures are suitably used as adsorbents for adsorbing and desorbing refrigerants.

[0016] The refrigeration apparatus of the seventh aspect is a refrigeration apparatus according to any of the first to seventh aspects, wherein the refrigerant comprises at least one of carbon dioxide, hydrocarbons, ammonia, water, hydrofluorocarbons (HFCs), and hydrofluoroolefins (HFOs).

[0017] As in the refrigeration apparatus of the seventh aspect, a refrigerant containing at least one of carbon dioxide, hydrocarbons, ammonia, water, HFCs, and HFOs is suitably used as a refrigerant in a refrigeration apparatus equipped with an adsorption refrigeration cycle.

[0018] This is a conceptual diagram of a refrigeration system equipped with a refrigeration cycle. This is a graph showing the relationship between the amount of adsorption by the adsorbent and the pressure of the refrigerant. This is a graph showing the relationship between the amount of adsorption by the adsorbent and the enthalpy of the refrigerant. This is a schematic diagram of a refrigeration system of an embodiment. This is a block diagram of a refrigeration system of an embodiment. This is a schematic diagram of the heat recovery section of an embodiment. This is a cross-sectional view of the heat transfer tubes constituting the heat recovery section of an embodiment. This is a diagram showing the relationship between capacity and ratio. This is a diagram showing an image of the refrigerant and adsorbent flowing inside the first heat transfer tube (second heat transfer tube). This is a schematic diagram of the first cross-section of the first heat transfer tube (second heat transfer tube) at the first capacity. This is a schematic diagram of the first cross-section of the first heat transfer tube (second heat transfer tube) at the second capacity.

[0019] (1) Overview of the refrigeration cycle The refrigeration system of this embodiment is equipped with a refrigeration cycle that utilizes the heat generated when an adsorbent adsorbs a refrigerant and when an adsorbent desorbs a refrigerant. The refrigeration system is, for example, an air conditioning system.

[0020] The refrigeration system of this embodiment is a circulating type refrigeration system in which an adsorbent and a refrigerant circulate. As shown in Figure 1, the circulating type refrigeration system 1 includes a refrigerant circuit 11 through which the refrigerant circulates, and an adsorption circuit 12 through which the adsorbent circulates. In Figure 1, the refrigerant circuit 11 and the adsorption circuit 12 are described as separate circuits. The refrigeration system 1 may also have a configuration in which the refrigerant circuit 11 and the adsorption circuit 12 merge into a flow path. In this case, the refrigeration system 1 is part of the refrigerant circuit 11 and the adsorption circuit 12 and has a flow path through which a mixture of the refrigerant and the adsorbent circulates. Alternatively, the refrigeration system 1 may have only one circuit through which a mixture of the refrigerant and the adsorbent circulates.

[0021] The refrigeration device 1 has an adsorption section 21 and a desorption section 22. Both the adsorption section 21 and the desorption section 22 include a part of the refrigerant circuit 11 and a part of the adsorption circuit 12. In the adsorption section 21, the refrigerant from the refrigerant circuit 11 is adsorbed onto the adsorbent material flowing through the adsorption circuit 12. In the desorption section 22, the refrigerant adsorbed in the adsorption section 21 is desorbed from the adsorbent material flowing through the adsorption circuit 12.

[0022] The refrigerant circuit 11 includes a compressor 31 and an expansion mechanism 32. The compressor 31 compresses the refrigerant circulating within the refrigerant circuit 11. The expansion mechanism 32 reduces the pressure of 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 reduced in pressure by the expansion mechanism 32, passes through the desorption section 22, and is compressed again by the compressor 31.

[0023] The refrigerant circuit 11 has a high-pressure region and a low-pressure region. In the high-pressure region, the refrigerant flows after being compressed by the compressor 31 and before being depressurized by the expansion mechanism 32. In the low-pressure region, the refrigerant flows after being depressurized 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.

[0024] The refrigerant circulating within the refrigerant circuit 11 includes at least one of carbon dioxide, hydrocarbons, ammonia, water, HFCs (hydrofluorocarbons), and HFOs (hydrofluoroolefins). The hydrocarbons are selected from the group consisting of, for example, propane, butane, and isobutane.

[0025] The adsorption circuit 12 includes a booster 41 and a pressure reducer 42. The booster 41 transports the adsorbent material to the adsorption section 21 in the adsorption circuit 12. The pressure reducer 42 transports the adsorbent material to the attachment / detachment section 22 in 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 material passes through the adsorption section 21 via the booster 41 and through the attachment / detachment section 22 via the pressure reducer 42.

[0026] The adsorption circuit 12 may further include a heat exchanger 43. The heat exchanger 43 performs heat exchange between the upstream side of the booster 41 and the upstream side of the depressurizer 42. The heat exchanger 43 transfers a portion of the heat from the adsorbent flowing between the adsorption section 21 and the depressurizer 42 to the adsorbent flowing between the desorption section 22 and the booster 41.

[0027] The adsorbent circulating in the adsorption circuit 12 includes a metal-organic structure containing metal ions and organic ligands. A metal-organic structure (MOF) is a porous material with a very large specific surface area obtained by the reaction of metal ions and organic ligands. In a metal-organic structure, a polymer structure with countless openings inside is obtained by the linkage of organic ligands with metal ions. The opening diameter and topology of the metal-organic structure can be adjusted by selecting and combining metal ions and organic ligands. By selecting and combining metal ions and organic ligands, the opening diameter of the metal-organic structure can be adjusted, making it possible to selectively adsorb target substances. For example, the metal-organic structure is used as a porous material having the function of selective storage and separation of molecules and ions. In this embodiment, the metal-organic structure is used as an adsorbent for adsorbing and desorbing a refrigerant. Examples of metal-organic structures include MOF-5, MOF-200, UiO-66, and MIL-101. The adsorbent is, for example, a powder of the metal-organic structure.

[0028] (2) Operation of the refrigeration system 1 The operation of the circulating refrigeration system 1 will be explained 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 in response 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.

[0029] Assume that the high-pressure region of the refrigerant circuit 11 is filled with refrigerant at pressure pH and temperature TH. Assume that the low-pressure region of the refrigerant circuit 11 is filled with refrigerant at pressure pL and temperature TL. Pressure pH is higher than pressure pL. Temperature TH is higher than temperature TL. The adsorbent adsorbs refrigerant in the high-pressure region of the refrigerant circuit 11. The adsorbent desorbs refrigerant in the low-pressure region of the refrigerant circuit 11. In the adsorption section 21, the refrigerant flowing in the high-pressure region of the refrigerant circuit 11 is adsorbed onto the adsorbent of the adsorption circuit 12. In the desorption section 22, the refrigerant is desorbed from the adsorbent flowing through the adsorption circuit 12.

[0030] The operation of the heat pump cycle of the refrigeration system 1 will be explained with reference to Figures 1 to 3. Figures 1 to 3 show 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 the 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 the enthalpy of the refrigerant adsorbed on the adsorbent, in the heat pump cycle. In the refrigeration system 1, it is assumed that heat can flow freely between the refrigerant circuit 11 and the adsorption circuit 12.

[0031] In the refrigerant circuit 11, the refrigerant is compressed by the compressor 31 (a→b). In the adsorption circuit 12, the adsorbent is circulated using the booster 41 (a'→b'). As a result, the pressure of the refrigerant rises from pL to pH. During this process, some 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 rises from TL to TH.

[0032] Next, in the adsorption section 21, the refrigerant is gradually adsorbed onto the adsorbent while releasing heat Q2 (b'→c'). During this process, the amount of adsorption by the adsorbent increases from mL to mH. As a result, in the adsorption section 21, the refrigerant from the refrigerant circuit 11 is adsorbed onto the adsorbent of the adsorption circuit 12. In Figure 1, as indicated by the hatched arrows within the adsorption section 21, the refrigerant from the refrigerant circuit 11 is adsorbed onto the adsorbent circulating in the adsorption circuit 12.

[0033] Next, in the refrigerant circuit 11, the refrigerant is depressurized by the expansion mechanism 32 (c→d). In the adsorption circuit 12, the adsorbent is circulated by the pressure reducer 42. As a result, the refrigerant pressure decreases from pH to pL. During this process, the temperature of the adsorbent decreases from TH to TL due to the isenthalpic expansion of the refrigerant desorbed from the adsorbent. Also, due to the temperature difference between the refrigerant and the adsorbent, the adsorbent in the adsorption circuit 12 is cooled, transferring heat Q3 to the refrigerant in the refrigerant circuit 11. Furthermore, heat Q5 is transferred from the adsorbent before it passes through the pressure reducer 42 to the adsorbent before it passes through the pressure booster 41 by the heat exchanger 43.

[0034] Next, in the desorption section 22, the refrigerant is gradually desorbed from the adsorbent while absorbing heat Q4 (d'→a'). During this process, the amount of adsorbed material decreases from mH to mL. As a result, the refrigerant adsorbed on the adsorbent in the adsorption circuit 12 is desorbed. In Figure 1, as indicated by the hatched arrows within the desorption section 22, the refrigerant is desorbed from the adsorbent in the adsorption circuit 12 in the desorption section 22.

[0035] As shown in Figure 2, during the adsorption process (b'→c') in which the refrigerant is adsorbed onto the adsorbent, the pressure of the refrigerant is pH, and the amount of adsorbed by the adsorbent increases from mL to mH. During the desorption process (d'→a') in which the refrigerant is desorbed from the adsorbent, the pressure of the refrigerant is pL, and the amount of adsorbed by 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 part 21 is proportional to Δh1. During the desorption process, the heat Q4 absorbed by the desorption part 22 is proportional to Δh2.

[0036] In the refrigeration device 1, heat Q2 is released in the adsorption section 21 (first heat recovery section), generating warmth, and heat Q4 is absorbed in the desorption section 22 (second heat recovery section), generating coldness. When the warmth generated in the adsorption section 21 is recovered by another heat transfer medium, the temperature of that heat transfer medium rises. When the coldness generated in the desorption section 22 is recovered by another heat transfer medium, the temperature of that heat transfer medium decreases.

[0037] (3) Detailed Configuration (3-1) Configuration of the Refrigeration System 100 The specific configuration of the circulating refrigeration system 100 will be explained with reference to the drawings.

[0038] As shown in Figure 4, the refrigeration device 100 of this embodiment includes a flow path 111 through which the refrigerant circulates. The flow path 111 has the functions of both the refrigerant circuit 11 and the adsorption circuit 12 of Figure 1. The adsorbent circulates within the flow path 111 together with the refrigerant. In other words, in the refrigeration device 100, a mixture of the refrigerant and the adsorbent flows within the flow path 111. In this embodiment, since the refrigerant is in the gas phase and the adsorbent is a powder of an adsorbent material, a mixture of the gaseous refrigerant and the solid adsorbent circulates within the flow path 111.

[0039] In Figure 4, the flow path 111 has a first flow path 111a through which the mixture flows, a second flow path 111b through which only the refrigerant flows, and a third flow path 111c through which only the adsorbent flows. The second flow path 111b and the third flow path 111c merge at a confluence 111d.

[0040] The refrigeration system 100 includes a compressor 131, a booster 141, a depressurization mechanism 132, a first heat recovery unit 133, a second heat recovery unit 134, a switching mechanism 135, a first fan 136, a second fan 137, and a separation unit 138. The flow path 111 connects the compressor 131, the booster 141, the depressurization mechanism 132, the first heat recovery unit 133, the second heat recovery unit 134, the switching mechanism 135, and the separation unit 138.

[0041] The compressor 131 has the same function as the compressor 31 in Figure 1. The compressor 131 is a transport mechanism that transports refrigerant into the flow path 111. Here, the compressor 131 is located in the second flow path 111b.

[0042] The booster 141 has the same function as the booster 41 in Figure 1. The booster 141 is a transport mechanism that transports the adsorbent into the flow path 111. Here, the booster 141 is located in the third flow path 111c.

[0043] The decompression mechanism 132 has the functions of both the expansion mechanism 32 and the decompressor 42 in FIG. 1. The decompression mechanism 132 has a function of adjusting the opening degree of the passage through which the mixture passes. The decompression mechanism 132 is, for example, a regulating valve with a variable opening degree, an expander with a variable rotational speed, or a capillary tube.

[0044] The switching mechanism 135 switches the flow direction of the mixture circulating in the 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 flow path 111 between a first state in the flow direction indicated by the solid line in FIG. 4 and a second state in the flow direction indicated by the dashed line in FIG. 4. When the flow path 111 is in the first state, the discharge sides of the compressor 131 and the pressure booster 141 are connected to the first heat recovery section 133, and the suction sides of the compressor 131 and the pressure booster 141 are connected to the second heat recovery section 134. When the flow path 111 is in the second state, the discharge sides of the compressor 131 and the pressure booster 141 are connected to the second heat recovery section 134, and the suction sides of the compressor 131 and the pressure booster 141 are connected to the first heat recovery section 133.

[0045] In the first heat recovery section 133, the refrigerant is adsorbed by the adsorbent while the flow path 111 is in the first state, and the refrigerant is desorbed from the adsorbent while the flow path 111 is in the second state. In the second heat recovery section 134, the refrigerant is desorbed from the adsorbent while the flow path 111 is in the first state, and the refrigerant is adsorbed by the adsorbent while the flow path 111 is in the second state.

[0046] While the flow path 111 is in the first state, adsorption heat is generated in the first heat recovery section 133, and desorption heat is generated in the second heat recovery section 134. While the flow path 111 is in the second state, desorption heat is generated in the first heat recovery section 133, and adsorption heat is generated in the second heat recovery section 134. Adsorption heat is the heat generated when the adsorbent adsorbs the refrigerant. Desorption heat is the cold heat generated when the adsorbent desorbs the refrigerant.

[0047] The adsorption heat or desorption heat generated in the first heat recovery section 133 and the second heat recovery section 134 is recovered by the air around the first heat recovery section 133 and the second heat recovery section 134. Therefore, the air around the first heat recovery section 133 and the second heat recovery section 134 is heated by the adsorption heat or cooled by the desorption heat. The first fan 136 sends the air heated or cooled in the first heat recovery section 133 to a predetermined location. The second fan 137 sends the air heated or cooled in the second heat recovery section 134 to a predetermined location.

[0048] In this way, in the refrigeration device 100, during the process in which the mixture circulates in the flow path 111, the air heated by the adsorption heat or cooled by the desorption heat is sent to a predetermined location. When the refrigeration device 100 is an air conditioner, for example, the first heat recovery section 133 corresponds to an outdoor heat exchanger, and the second heat recovery section 134 corresponds to an indoor heat exchanger. In this case, by switching the flow path 111 to the first state, the refrigerant is desorbed from the adsorbent in the second heat recovery section 134 and desorption heat is generated. The air cooled by the desorption heat is sent to a predetermined location by the second fan 137. Further, by switching the flow path 111 to the second state, the refrigerant is adsorbed by the adsorbent in the second heat recovery section 134 and adsorption heat is generated. The air heated by the adsorption heat is sent to a predetermined location by the second fan 137.

[0049] The separation section 138 is a container or device that separates the mixture decompressed by passing through the decompression mechanism 132 into a refrigerant and an adsorbent. The separation section 138 is, for example, a container having a mechanism for swirling the mixture inside to centrifugally separate the adsorbent. The adsorbent separated in the separation section 138 falls by gravity and is stored in the first space 138a at the bottom of the container of the separation section 138. In FIG. 4, the adsorbent stored in the first space 138a is shown as a hatched area. The refrigerant separated in the separation section 138 stays in the second space 138b above the first space 138a.

[0050] The separation unit 138 has an inlet 138c, a first outlet 138d, and a second outlet 138e. The mixture flows into the inlet 138c. The inlet 138c is connected to the first flow path 111a. The refrigerant flows out of the second space 138b through the first outlet 138d. The first outlet 138d is connected to the second flow path 111b. The adsorbent flows out of the first space 138a through the second outlet 138e. The second outlet 138e is connected to the third flow path 111c.

[0051] The refrigeration system 100 further includes a control unit 105 as shown in Figure 5. The control unit 105 controls the operation of each component of the refrigeration system 100. Here, a processor is given as an example of the control unit 105. The processor consists 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 device into memory and executes them. The processor loads the programs stored in memory into the working area of ​​the memory and executes them, and by controlling each component through the execution of the programs, it realizes functions that match a predetermined purpose.

[0052] As shown in Figure 5, the control unit 105 controls the compressor 131, the pressure reducing mechanism 132, the switching mechanism 135, the first fan 136, the second fan 137, and the booster 141. The control unit 105 controls the rotational speed of the compressor 131. The control unit 105 controls the timing for starting the compressor 131 and the timing for stopping the compressor 131. The control unit 105 controls the opening degree of the pressure reducing mechanism 132. The control unit 105 controls the switching mechanism 135 to switch the flow path 111 between a first state and a second state. The control unit 105 controls the rotational speed of the first fan 136 and the second fan 137. The control unit 105 controls the rotational speed of the booster 141. The control unit 105 controls the timing for starting the booster 141 and the timing for stopping the booster 141.

[0053] In this embodiment, the control unit 105 adjusts the capacity of at least one of the first heat recovery unit 133 and the second heat recovery unit 134 to a first capacity and a second capacity different from the first capacity by changing at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reducing mechanism 132. If the pressure reducing mechanism 132 is an electric valve, the control unit 105 adjusts the capacity of at least one of the first heat recovery unit 133 and the second heat recovery unit 134 to a first capacity and a second capacity greater than the first capacity by changing at least one of the rotational speed of the compressor 131 and the opening degree of the pressure reducing mechanism 132. The first capacity and the second capacity are arbitrary capacities requested by the user.

[0054] (3-2) Operation of the refrigeration unit 100 The refrigeration unit 100 is an air conditioning system in which the first heat recovery unit 133 is an outdoor heat exchanger and the second heat recovery unit 134 is an indoor heat exchanger. When the flow path 111 is in the first state, the refrigeration unit 100 performs cooling operation. When the flow path 111 is in the second state, the refrigeration unit 100 performs heating operation.

[0055] (3-2-1) When the first state flow path 111 is in the first state, as shown by the solid arrows in Figure 4, the discharge side of the compressor 131 is connected to the first heat recovery unit 133 to create a high-pressure state inside the first heat recovery unit 133, and the suction side of the compressor 131 is connected to the second heat recovery unit 134 to create a low-pressure state inside the second heat recovery unit 134. As a result, the adsorbent flowing through the flow path 111 adsorbs the refrigerant in the first heat recovery unit 133 and desorbs the refrigerant in the second heat recovery unit 134.

[0056] When the flow path 111 is in the first state, the mixture that has passed through the second heat recovery unit 134 flows into the separation unit 138 and is separated into refrigerant and adsorbent. The refrigerant separated in the separation unit 138 flows from the second space 138b through the first outlet unit 138d into the second flow path 111b, is compressed by the compressor 131, and then flows to the confluence unit 111d. The adsorbent separated in the separation unit 138 flows from the first space 138a through the second outlet unit 138e into the third flow path 111c, is pressurized by the booster 141, and then flows to the confluence unit 111d. In the confluence unit 111d, the refrigerant and adsorbent are mixed to form a mixture, which passes through the switching mechanism 135, the first heat recovery unit 133, the pressure reducing mechanism 132, the second heat recovery unit 134, and the switching mechanism 135 in that order, and flows into the separation unit 138 via the inlet unit 138c.

[0057] In the above operation, the control unit 105 appropriately changes the capacity of the first heat recovery unit 133, which recovers adsorption heat, by changing at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reduction mechanism 132.

[0058] (3-2-2) Second state When the flow path 111 is in the second state, as shown by the dotted arrow in Figure 4, the discharge side of the compressor 131 is connected to the second heat recovery unit 134 to create a high-pressure state inside the second heat recovery unit 134, and the suction side of the compressor 131 is connected to the first heat recovery unit 133 to create a low-pressure state inside the first heat recovery unit 133. As a result, the adsorbent flowing through the flow path 111 adsorbs the refrigerant in the second heat recovery unit 134 and desorbs the refrigerant in the first heat recovery unit 133.

[0059] When the flow path 111 is in the second state, the mixture that has passed through the first heat recovery unit 133 flows into the separation unit 138 and is separated into refrigerant and adsorbent. The refrigerant separated in the separation unit 138 flows from the second space 138b through the first outlet unit 138d into the second flow path 111b, is compressed by the compressor 131, and then flows to the confluence unit 111d. The adsorbent separated in the separation unit 138 flows from the first space 138a through the second outlet unit 138e into the third flow path 111c, is pressurized by the booster 141, and then flows to the confluence unit 111d. In the confluence unit 111d, the refrigerant and adsorbent are mixed to form a mixture, which passes through the switching mechanism 135, the second heat recovery unit 134, the pressure reducing mechanism 132, the first heat recovery unit 133, and the switching mechanism 135 in that order, and flows into the separation unit 138 via the inlet unit 138c.

[0060] In the above operation, the control unit 105 appropriately changes the capacity of the second heat recovery unit 134, which recovers adsorption heat, by changing at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reduction mechanism 132.

[0061] (3-3) Details of the refrigeration device 100 The first heat recovery unit 133 and the second heat recovery unit 134 are of the cross-fin type, as shown in Figure 6. The first heat recovery unit 133 has a first heat transfer tube 133a and a plurality of first fins 133b. The second heat recovery unit 134 has a second heat transfer tube 134a and a plurality of second fins 134b.

[0062] The first heat transfer tube 133a and the second heat transfer tube 134a constitute the flow path 111. In other words, the mixture passes through the inside of the first heat transfer tube 133a and the second heat transfer tube 134a. The first heat transfer tube 133a and the second heat transfer tube 134a are round tubes. The first heat transfer tube 133a and the second heat transfer tube 134a have multiple straight pipe sections extending in a straight line and folded sections connecting two straight pipe sections.

[0063] The first heat transfer tube 133a and the second heat transfer tube 134a have inlets 133a1, 134a1 and outlets 133a2, 134a2. Inlets 133a1, 134a1 are inlets through which the mixture flows into the first heat recovery section 133 and the second heat recovery section 134. Outlets 133a2, 134a2 are outlets through which the mixture flows out of the first heat recovery section 133 and the second heat recovery section 134.

[0064] As shown in Figure 7, the inner surfaces of the first heat transfer tube 133a and the second heat transfer tube 134a have irregularities. In other words, the first heat transfer tube 133a and the second heat transfer tube 134a are internally grooved tubes. The internally grooved tubes have a circular outer surface in cross-section, while grooves are formed on the inner surface through which the refrigerant flows, thereby improving heat transfer performance.

[0065] The first fin 133b and the second fin 134b increase the heat transfer area between the first heat transfer tube 133a and the second heat transfer tube 134a and the air, thereby promoting heat exchange. The first fin 133b and the second fin 134b have through holes in their thickness direction through which the straight sections of the first heat transfer tube 133a and the second heat transfer tube 134a pass. The first fin 133b and the second fin 134b are arranged around the straight sections of the first heat transfer tube 133a and the second heat transfer tube 134a so as to be stacked at predetermined intervals along the direction in which the straight sections extend.

[0066] When the control unit 105 adjusts the capacity of the first heat recovery unit 133 (while the flow path 111 is in the first state) or the second heat recovery unit 134 (while the flow path 111 is in the second state) that recovers adsorption heat by changing at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reduction mechanism 132 to a first capacity and a second capacity different from the first capacity, it changes the ratio of refrigerant occupying the first cross-section of the first heat transfer tube 133a when the flow path 111 is in the first state or the second heat transfer tube 134a when the flow path 111 is in the second state.

[0067] In this specification, when "changing (adjusting) the capacity," the flow rate of the mixture circulating in the flow path 111 is kept constant, and the pressure of the mixture is changed. In other words, in this specification, the capacity is changed by changing the differential pressure between the low pressure and the high pressure in the flow path 111.

[0068] Here, the control unit 105 changes at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reducing mechanism 132 to change the capacity of the first heat recovery unit 133 (while the flow path 111 is in the first state) or the second heat recovery unit 134 (while the flow path 111 is in the second state), which recovers adsorption heat, from the first capacity to a second capacity which is greater than the first capacity, and as shown in Figure 8, reduces the area ratio of the refrigerant occupying the first cross-section of the first heat transfer tube 133a or the second heat transfer tube 134a. In other words, when the control unit 105 changes the capacity of the first heat recovery unit 133 when the flow path 111 is in the first state, or the second heat recovery unit 134 when the flow path 111 is in the second state, from the first capacity to the second capacity, it controls at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reducing mechanism 132 so that the area ratio of the refrigerant occupying the first cross-section of the first heat transfer tube 133a or the second heat transfer tube 134a is reduced. Specifically, when the control unit 105 increases the capacity of the first heat recovery unit 133 or the second heat recovery unit 134 in which the adsorbent generates heat, it increases the rotational speed of the compressor 131 and / or increases the throttling amount of the pressure reducing mechanism 132 (for example, if the pressure reducing mechanism 132 is a control valve, it decreases the opening, and if the pressure reducing mechanism 132 is an expander, it decreases the rotational speed) to reduce the ratio.

[0069] Furthermore, when the control unit 105 changes at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reducing mechanism 132 to change the capacity of the first heat recovery unit 133 or the second heat recovery unit 134 that recovers adsorption heat from the second capacity to a first capacity which is smaller than the second capacity, it increases the area ratio of the refrigerant occupying the first cross-section of the first heat transfer tube 133a or the second heat transfer tube 134a, as shown in Figure 8. In other words, when the control unit 105 changes the capacity of the first heat recovery unit 133 when the flow path 111 is in the first state, or the second heat recovery unit 134 when the flow path 111 is in the second state, from the second capacity to the first capacity, it controls at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reducing mechanism 132 so that the area ratio of the refrigerant occupying the first cross-section of the first heat transfer tube 133a or the second heat transfer tube 134a decreases. Specifically, when the control unit 105 reduces the capacity of the adsorption-side first heat recovery unit 133 or second heat recovery unit 134, it reduces the rotational speed of the compressor 131 and / or reduces the throttling amount of the pressure reducing mechanism 132 (for example, if the pressure reducing mechanism 132 is a control valve, it increases the opening, and if the pressure reducing mechanism 132 is an expander, it increases the rotational speed) to increase the ratio.

[0070] Figure 8 shows the relationship between the ratio in the first cross-section of the first heat transfer tube 133a when the flow path 111 is in the first state, or the second heat transfer tube 134a when the flow path 111 is in the second state, and the capacity, in the same first cross-section. In Figure 8, the horizontal axis represents capacity and the vertical axis represents ratio.

[0071] The ratio is a value obtained by cutting the first heat transfer tube 133a when the flow path 111 is in the first state, or the second heat transfer tube 134a when the flow path 111 is in the second state, at a first cross-section, and calculating the ratio of the area occupied by the refrigerant to the cross-sectional area of ​​the first cross-section (unit: none). The first cross-section is the cross-section obtained by cutting at an arbitrary first point between the inlet 133a1 and outlet 133a2 of the first heat transfer tube 133a when the flow path 111 is in the first state, and the cross-section obtained by cutting at an arbitrary first point between the inlet 134a1 and outlet 134a2 of the second heat transfer tube 134a when the flow path 111 is in the second state. In this embodiment, the first cross-section is the cross-section obtained by cutting at the outlet 133a2 of the first heat transfer tube 133a when the flow path 111 is in the first state, and the cross-section obtained by cutting at the outlet 134a2 of the second heat transfer tube 134a when the flow path 111 is in the second state. At the outlet 133a2 of the first heat transfer tube 133a in the first state, and at the outlet 134a2 of the second heat transfer tube 134a in the second state, the adsorption of the refrigerant in the circulating mixture onto the adsorbent is almost complete. However, the cross-section of the refrigerant and the adsorbent is more stable at these outlets than at other heat transfer tube sections where the progression of adsorption continues to change. Therefore, the first cross-section is designated as the outlets 133a2 and 134a2.

[0072] The inlet 133a1 and outlet 133a2 of the first heat transfer tube 133a, and the inlet 134a1 and outlet 134a2 of the second heat transfer tube 134a are the connection points between the inlet and outlet sides of the refrigerant in the first heat recovery unit 133 and the flow path 111, and the connection points between the inlet and outlet sides of the refrigerant in the second heat recovery unit 134 and the flow path 111.

[0073] Here, we will explain the ratio. Figure 9 shows an image of the refrigerant g and adsorbent m flowing simultaneously inside a section of the first heat transfer tube 133a when the flow path 111 is in the first state, or the second heat transfer tube 134a when the flow path 111 is in the second state. The refrigerant g is in the gas phase and the adsorbent A is a solid, and this is an example of a flow mode in which the adsorbent flows downwards and the refrigerant flows upwards inside the first heat transfer tube 133a or the second heat transfer tube 134a.

[0074] Figure 10 is a schematic diagram of the first cross-section C (see Figure 9) of the first heat transfer tube 133a or the second heat transfer tube 134a where the adsorbent m adsorbs the refrigerant g at a relatively low first capacity. Figure 11 is a schematic diagram of the first cross-section C (see Figure 9) of the first heat transfer tube 133a or the second heat transfer tube 134a where the adsorbent m adsorbs the refrigerant g at a relatively high second capacity. In Figures 9 to 11, the inner surface of the heat transfer tube is shown as a circle for illustrative purposes. In Figures 10 and 11, the area Am of the adsorbent m and the area Ag of the refrigerant g occupying the first cross-section C are shown for comparison using the same first cross-section C.

[0075] As shown in Figures 10 and 11, the cross-sectional area of ​​the first section C is the sum of the area Am of the adsorbent occupying the first section C and the area Ag of the refrigerant occupying the first section C. Therefore, by cutting the first heat transfer tube 133a or the second heat transfer tube 134a that generates heat at the first section C and obtaining the area Am of the adsorbent and the area Ag of the refrigerant, the ratio can be determined from the formula Ag / (Am + Ag). Alternatively, the area Am of the adsorbent and the area Ag of the refrigerant may be obtained by imaging the first section C and performing image analysis.

[0076] In the first cross-section C of the first heat transfer tube 133a or the second heat transfer tube 134a that generates heat, the ratio of refrigerant g occupying the upper part (Ag / (Am+Ag)) when the second capacity, which has a relatively higher capacity as shown in Figure 11, is smaller than the ratio of refrigerant g occupying the upper part (Ag / (Am+Ag)) when the first capacity, which has a relatively lower capacity as shown in Figure 10.

[0077] As shown in Figure 8, Figure 8 is a graph showing the calculated ratios for five different capacities in the same first cross-section C. As shown in Figure 8, the control unit 105 controls the compressor 131 and the pressure reducing mechanism 132 so as to decrease the ratio when increasing the capacity of the heat recovery unit that generates heat, and increase the ratio when decreasing the capacity.

[0078] For example, when the control unit 105 changes the capacity of the first heat recovery unit 133 or the second heat recovery unit 134 that recovers adsorption heat between a minimum capacity and a maximum capacity by changing at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reduction mechanism 132, it changes the area ratio of the refrigerant occupying the first cross-section C of the first heat transfer tube 133a or the second heat transfer tube 134a between 0.5 and 0.7.

[0079] Furthermore, when the control unit 105 changes at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reducing mechanism 132 to change the capacity of the first heat recovery unit 133 (while the flow path 111 is in the first state) or the second heat recovery unit 134 (while the flow path 111 is in the second state), which recovers heat of adsorption, from the first capacity to a second capacity which is greater than the first capacity, it slows down the flow velocity of the mixture. Also, when the control unit 105 changes at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reducing mechanism 132 to change the capacity of the first heat recovery unit 133 or the second heat recovery unit 134, which generates heat, from the second capacity to a first capacity which is smaller than the second capacity, it speeds up the flow velocity of the mixture. In this way, the control unit 105 controls at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reducing mechanism 132 to slow down the flow velocity of the mixture when the capacity of the heat recovery unit that generates heat is increased, and to speed up the flow velocity of the refrigerant when the capacity is decreased.

[0080] Note that the flow velocity [unit: m] ３ The flow rate [ / s] can be obtained by measuring the mixture in the first heat transfer tube 133a or the second heat transfer tube 134a with a flow meter. The flow velocity may also be obtained by measuring each of the flow rates with a flow meter when the mixture is separated into the adsorbent and the refrigerant (for example, in the second flow path 111b and the third flow path 111c) and summing them up.

[0081] Furthermore, when the first capacity is reached, if the flow path 111 is in the first state, the ratio at the outlet 133a2 of the first heat transfer tube 133a is smaller than the ratio at the inlet 133a1 of the first heat transfer tube 133a. If the flow path 111 is in the second state, the ratio at the outlet 134a2 of the second heat transfer tube 134a is smaller than the ratio at the inlet 134a1 of the second heat transfer tube 134a. When the same capacity is required, the control unit 105 controls the ratio to decrease from the inlet to the outlet of the heat transfer tubes in the heat recovery unit that generate heat.

[0082] In this case, the ratio of the inlet 133a1 to the outlet 133a2 of the first heat transfer tube 133a of the first heat recovery unit 133 that recovers adsorption heat, or the ratio of the inlet 134a1 to the outlet 134a2 of the second heat transfer tube 134a of the second heat recovery unit 134 that recovers adsorption heat, is calculated as described above.

[0083] (3-4) Features (3-4-1) In a circulating refrigeration system, in the heat recovery section, an adsorbent that generates heat when adsorbing the refrigerant transfers heat to the heat transfer medium on the utilization side (air in the above embodiment) via a heat transfer tube. However, since the refrigerant also flows through the heat transfer tube, it is desirable to efficiently transfer the heat from the adsorbent to the heat transfer tube when increasing the capacity of the refrigeration system. As a result of the inventors' diligent investigation into this problem, they discovered a novel parameter, the area ratio of the refrigerant occupying the first cross-section of the heat transfer tube, and determined that this ratio should be changed when changing the capacity, thereby completing the present invention.

[0084] The refrigeration system 100 of this embodiment is a refrigeration system through which a refrigerant and an adsorbent are circulated. The adsorbent adsorbs and desorbs the refrigerant in response to changes in the pressure of the refrigerant. The refrigeration system 100 includes a compressor 131, a pressure reducing mechanism 132, a first heat recovery unit 133, a second heat recovery unit 134, and a control unit 105. The compressor 131 compresses the refrigerant. The pressure reducing mechanism 132 reduces the pressure of the refrigerant. The control unit 105 controls the compressor 131 and the pressure reducing mechanism 132. The first heat recovery unit 133 has a first heat transfer tube 133a through which a mixture of refrigerant and adsorbent passes. The second heat recovery unit 134 has a second heat transfer tube 134a through which a mixture of refrigerant and adsorbent passes.

[0085] When the flow path 111 is in the first state, the first heat recovery unit 133 recovers the heat generated when the adsorbent adsorbs the refrigerant, and the second heat recovery unit 134 recovers the cold generated when the adsorbent desorbs the refrigerant. When the control unit 105 changes the capacity of the first heat recovery unit 133 from the first capacity to a second capacity which is greater than the first capacity by changing at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reducing mechanism 132, it reduces the area ratio of the refrigerant occupying the first cross-section C of the first heat transfer tube 133a. Here, the first cross-section C is the cross-section of the outlet 133a2 of the first heat transfer tube 133a.

[0086] When the flow path 111 is in the second state, the second heat recovery unit 134 recovers the heat generated when the adsorbent adsorbs the refrigerant, and the first heat recovery unit 133 recovers the cold generated when the adsorbent desorbs the refrigerant. When the control unit 105 changes the capacity of the second heat recovery unit 134 from the first capacity to a second capacity which is greater than the first capacity by changing at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reducing mechanism 132, it reduces the area ratio of the refrigerant occupying the first cross-section C of the second heat transfer tube 134a. Here, the first cross-section C is the cross-section of the outlet 134a2 of the second heat transfer tube 134a.

[0087] In the refrigeration system 100 of this embodiment, the control unit 105 changes the ratio when adjusting the capacity of the first heat recovery unit 133 or the second heat recovery unit 134, which recovers the heat generated when the adsorbent adsorbs the refrigerant, to a first capacity and a second capacity by changing at least one of the rotational speed of the compressor 131 and the throttling amount of the pressure reduction mechanism 132. Here, the control unit 105 decreases the ratio when increasing the capacity. When the ratio decreases, the volume ratio of the adsorbent that has heat inside the first heat transfer tube 133a or the second heat transfer tube 134a increases. As a result, the adsorbent that has heat can more easily come into contact with the inner surface of the first heat transfer tube 133a or the second heat transfer tube 134a, thereby improving the efficiency of transferring the heat of the adsorbent to the first heat transfer tube 133a or the second heat transfer tube 134a. Therefore, the capacity of the circulating refrigeration system 100 can be adjusted efficiently. In this way, the control unit 105 enables efficient operation at both the first capacity and the second capacity, which is greater than the first capacity.

[0088] (3-4-2) In the refrigeration apparatus 100 of this embodiment, preferably, the flow rate of the mixture at the second capacity is slower than the flow rate of the mixture at the first capacity.

[0089] Here, when increasing the capacity, the control unit 105 slows down the flow rate of the mixture of refrigerant and adsorbent. When the flow rate slows down, the adsorbent, which has heat, is more likely to come into contact with the inner surface of the first heat transfer tube 133a or the second heat transfer tube 134a in the first state or the second heat transfer tube 134a in the second state, and the contact time is also increased, so the efficiency of transferring the heat of the adsorbent to the first heat transfer tube 133a or the second heat transfer tube 134a can be improved. Therefore, the capacity can be adjusted with high efficiency.

[0090] (3-4-3) In the refrigeration apparatus 100 of this embodiment, preferably, when the flow path 111 is in the first state, the ratio at the outlet 133a2 of the first heat transfer tube 133a is smaller than the ratio at the inlet 133a1 of the first heat transfer tube 133a. Also, when the flow path 111 is in the second state, the ratio at the outlet 134a2 of the second heat transfer tube 134a is smaller than the ratio at the inlet 134a1 of the second heat transfer tube 134a.

[0091] In this configuration, the control unit 105, in the first state, reduces the ratio of the first heat transfer tube 133a at its outlet 133a2 to that at its inlet 133a1. Furthermore, in the second state, the control unit 105 reduces the ratio of the second heat transfer tube 134a at its outlet 134a2 to that at its inlet 134a1. By reducing the ratio from the inlets 133a1 and 134a1 to the outlets 133a2 and 134a2 in the first or second heat transfer tube 133a or second heat transfer tube 134a, the proportion of refrigerant within the tube decreases, leading to increased adsorption of the refrigerant onto the adsorbent. Consequently, the adsorbent can efficiently generate heat.

[0092] (3-4-4) In the refrigeration apparatus 100 of this embodiment, preferably, the inner surfaces of the first heat transfer tube 133a and the second heat transfer tube 134a have irregularities formed on them.

[0093] Here, since irregularities are formed on the inner surfaces of the first heat transfer tube 133a and the second heat transfer tube 134a, the contact area between the heat-generating adsorbent and the inner surface of the first heat transfer tube 133a or the second heat transfer tube 134a can be increased.

[0094] (3-4-5) In the refrigeration apparatus 100 of this embodiment, the depressurization mechanism 132 is preferably a control valve with a variable opening degree, an expander with a variable rotation speed, or a capillary tube.

[0095] Thus, the pressure reduction mechanism 132 may be a control valve with a variable opening degree, an expander with a variable rotation speed, or a capillary tube.

[0096] (3-4-6) The refrigeration apparatus of this embodiment is preferably 100, and the adsorbent includes a metal-organic structure containing a metal ion and an organic ligand.

[0097] Thus, metal-organic structures are suitably used as adsorbents for adsorbing and desorbing refrigerants.

[0098] (3-4-7) Preferably, in the refrigeration apparatus 100 of this embodiment, the refrigerant includes at least one of carbon dioxide, hydrocarbons, ammonia, water, HFCs, and HFOs.

[0099] Thus, refrigerants containing at least one of carbon dioxide, hydrocarbons, ammonia, water, HFCs, and HFOs are suitably used as refrigerants in adsorption-type refrigeration cycle systems.

[0100] (4) Modified Examples (4-1) Modified Example A In the above embodiment, the first heat recovery unit 133 and the second heat recovery unit 134 are of the cross-fin type, but are not limited thereto.

[0101] The first heat recovery unit 133 and the second heat recovery unit 134 may be, for example, a corrugated fin type, a shell and heat transfer tube type, a double-tube type, a plate type, or the like.

[0102] (4-2) Modification B In the above embodiment, the first heat transfer tube 133a was described using a round tube as an example, but it is not limited to this. The first heat transfer tube 133a may be a flattened multi-hole tube.

[0103] (4-3) Modification C In the above embodiment, the first heat recovery unit 133 and the second heat recovery unit 134 have the same configuration, but are not limited thereto. The first heat recovery unit 133 and the second heat recovery unit 134 may have different configurations.

[0104] (4-4) Modification D In the above embodiment, the adsorbent used in the refrigeration device 100 is a metal-organic structure, but is not limited thereto, and materials other than metal-organic structures may be used. Examples of materials other than metal-organic structures include activated carbon, zeolite-based materials, silica-based materials, and alumina-based materials.

[0105] (4-5) Modification E In the above embodiment, an air conditioning system was used as an example, but the invention is not limited thereto. The heat exchange medium that exchanges heat with the heat generated in the first heat recovery unit 133 and the second heat recovery unit 134 may be water, brine, or the like.

[0106] While embodiments of this disclosure have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of this disclosure as described in the claims.

[0107] 100: Refrigeration unit 105: Control unit 131: Compressor 132: Pressure reducing mechanism 133: First heat recovery unit 133a: First heat transfer tube (heat transfer tube) 133a1, 134a1: Inlet 133a2, 134a2: Outlet 134: Second heat recovery unit 134a: Second heat transfer tube (heat transfer tube)

[0108] U.S. Patent Application Publication No. 2023 / 0417459

Claims

1. A refrigeration system comprising: a compressor (131) for compressing the refrigerant; a pressure reducing mechanism (132) for reducing the pressure of the refrigerant; a first heat recovery unit (133, 134) for recovering the heat generated when the adsorbent material adsorbs the refrigerant; a second heat recovery unit (134, 133) for recovering the cold generated when the adsorbent material desorbs the refrigerant; and a control unit (105) for controlling the compressor and the pressure reducing mechanism, wherein the first heat recovery unit has heat transfer tubes (133a, 134a) through which a mixture of the refrigerant and the adsorbent passes; and the control unit reduces the area ratio of the refrigerant occupying the first cross-section of the heat transfer tube when changing the capacity of the first heat recovery unit from a first capacity to a second capacity greater than the first capacity by changing at least one of the rotational speed of the compressor and the throttling amount of the pressure reducing mechanism. Refrigeration device (100).

2. The refrigeration apparatus according to claim 1, wherein the flow rate of the mixture at the second capacity is slower than the flow rate of the mixture at the first capacity.

3. The refrigeration apparatus according to claim 1 or 2, wherein the ratio at the outlets (133a2, 134a2) of the heat transfer tubes is smaller than the ratio at the inlets (133a1, 134a1) of the heat transfer tubes.

4. The refrigeration apparatus according to any one of claims 1 to 3, wherein the inner surface of the heat transfer tube has irregularities formed on it.

5. The refrigeration apparatus according to any one of claims 1 to 4, wherein the pressure reduction mechanism is a control valve with a variable opening degree, an expander with a variable rotation speed, or a capillary tube.

6. The refrigeration apparatus according to any one of claims 1 to 5, wherein the adsorbent comprises a metal-organic structure containing a metal ion and an organic ligand.

7. The refrigeration apparatus according to any one of claims 1 to 6, wherein the refrigerant comprises at least one of carbon dioxide, hydrocarbons, ammonia, water, HFCs, and HFOs.

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