Adsorption-type refrigerator

Abstract

An adsorbent (24) has a difference between a first adsorption amount, which is an adsorption amount of water at a temperature of 25°C and a relative humidity of 30%, and a second adsorption amount, which is an adsorption amount of water at a temperature of 25°C and a relative humidity of 66%, the difference being greater than 0.17 [g / g].

Description

Adsorption refrigerator

[0001] The present disclosure relates to an adsorption chiller.

[0002] There is an adsorption chiller that operates in an adsorption heat pump cycle. The adsorption chiller described in Patent Document 1 includes two adsorbers, a condenser, and an evaporator. One of the two adsorbers performs an adsorption operation to adsorb water onto the adsorbent, and the other performs a regeneration operation to regenerate the water in the adsorbent. The adsorbent is regenerated using waste heat, for example, from a factory. The evaporator is connected to the adsorber in the adsorption operation, causing water around the evaporator's cooling coil to evaporate. This cools the water in the evaporator's cooling coil. The water evaporated in the evaporator is adsorbed by the adsorbent in the adsorption operation. When the adsorbent in the adsorber in the regeneration operation is regenerated using the factory's waste heat, water vapor is generated. This water vapor is cooled and condensed by the condenser and then sent to the evaporator.

[0003] JP 2014-37936 A

[0004] In an adsorption chiller such as that described in Patent Document 1, the temperature of the air used to regenerate the adsorbent in the adsorber varies depending on the operating conditions. For example, when the regeneration temperature (exhaust heat temperature) is relatively low, such as approximately 50°C, conventional adsorbents (e.g., silica gel) cannot fully utilize their adsorbent performance. This can result in the adsorption heat pump cycle not functioning properly or with reduced efficiency.

[0005] An object of the present disclosure is to provide an adsorption chiller that can prevent the adsorption heat pump cycle from becoming inoperable or from decreasing in efficiency when the regeneration temperature of the adsorbent is relatively low.

[0006] The first aspect is an adsorption chiller that includes an adsorber (20), an evaporator (40), and a condenser (50), each having an adsorbent (24) that adsorbs water, and that performs an adsorption heat pump cycle. The adsorbent (24) has a difference of more than 0.17 g / g between a first adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 30%, and a second adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66%.

[0007] In conventional adsorption chillers, the adsorbent used in the adsorber has a relatively large effective adsorption capacity at a relatively low relative humidity range (for example, a range of about 9% to 29%). With this adsorbent, the regeneration temperature becomes relatively low, which can prevent the adsorption heat pump cycle from operating or reduce its efficiency.

[0008] In contrast, in the adsorbent (24) of the first aspect, the difference between the first adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 30%, and the second adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66%, is greater than 0.17 [g / g]. By using an adsorbent (24) having such a relatively large difference in adsorption amount within a relative humidity range, the performance of the adsorbent (24) can be fully exhibited under conditions where the regeneration temperature is low. This makes it possible to prevent the adsorption heat pump cycle from failing to operate or from losing efficiency.

[0009] In a second aspect, the adsorbent (24) of the first aspect is configured such that the relationship between the relative humidity and the adsorption amount in the adsorption step is different from the relationship between the relative humidity and the adsorption amount in the desorption step. The first adsorption amount is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 30% in the desorption step. The second adsorption amount is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66% in the adsorption step.

[0010] The adsorbent (24) of the second aspect has different adsorption characteristics during the desorption process and the adsorption process. The difference between the first adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 30% during the desorption process, and the second adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66% during the adsorption process, is greater than 0.17 g / g. This allows the adsorbent (24) to fully exhibit its performance under conditions where the exhaust heat temperature is low. This prevents the adsorption heat pump cycle from failing to operate or from losing efficiency.

[0011] In a third aspect, in the first or second aspect, the regeneration temperature of the adsorbent (24) of the adsorber (20) is 45°C or higher and 60°C or lower.

[0012] In the third aspect, the regeneration temperature of the adsorbent (24) is relatively low, not less than 45° C. and not more than 60° C. However, the difference in adsorption amount of the adsorbent (24) in the relative humidity range of 30% to 66% is greater than 0.17 [g / g], and therefore the performance of the adsorbent (24) can be fully exhibited.

[0013] A fourth aspect is any one of the first to third aspects, wherein the evaporator (40) cools the object to a temperature of 20°C or higher and 25°C or lower.

[0014] In the fourth aspect, the object is cooled by the evaporator (40) to a temperature in the range of 20°C to 25°C.

[0015] In a fifth aspect, in any one of the first to fourth aspects, an electronic device (E) is cooled by the heat medium as the object cooled in the evaporator (40).

[0016] In the fifth aspect, the electronic device (E) can be cooled by the heat medium cooled in the evaporator (40).

[0017] A sixth aspect is any one of the first to fifth aspects, wherein the adsorbent (24) contains carbon, nitrogen, and oxygen, has an elemental ratio of the carbon to the nitrogen greater than 1.8, has a pore structure with a large number of pores, and has a ratio of the total volume of pores having a diameter of 2 nm or more and 50 nm or less to the weight of the adsorbent (24) of 0.32 cm 3 / g] or more.

[0018] In the sixth aspect, by using the adsorbent (24) having the above-described characteristics, the difference in the amount of adsorption becomes large within the relative humidity range of 30% to 66%.

[0019] A seventh aspect is any one of the first to fifth aspects, wherein the adsorbent (24) includes a metal-organic framework.

[0020] In the seventh aspect, a metal-organic framework (MOF) is used as the adsorbent (24) used in the adsorption refrigerator.

[0021] An eighth aspect is any one of the first to seventh aspects, wherein a single-stage adsorption heat pump cycle is performed.

[0022] In the eighth aspect, the device can be made smaller and simpler than one that performs a multi-stage adsorption heat pump cycle.

[0023] A ninth aspect of the present invention is an adsorption chiller that includes an adsorber (20), an evaporator (40), and a condenser (50), each of which has an adsorbent (24) that adsorbs water, and that performs an adsorption heat pump cycle. The adsorbent (24) is configured so that the relationship between the relative humidity and the adsorption amount in the adsorption process differs from the relationship between the relative humidity and the adsorption amount in the desorption process. The adsorbent (24) has a difference of more than 0.17 g / g between a third adsorption amount, which is the amount of water adsorbed at a temperature of 60°C and a relative humidity of 30% in the desorption process, and a fourth adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66% in the adsorption process.

[0024] The adsorbent (24) of the ninth aspect has different adsorption characteristics during the desorption process and the adsorption process. The difference between the third adsorption amount, which is the amount of water adsorbed at a temperature of 60°C and a relative humidity of 30% during the desorption process, and the fourth adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66% during the adsorption process, is greater than 0.17 g / g. This allows the adsorbent (24) to fully exhibit its performance under conditions of low regeneration temperatures. This prevents the adsorption heat pump cycle from failing to operate or from losing efficiency.

[0025] FIG. 1 is a schematic diagram of an adsorption refrigerator according to an embodiment. FIG. 2 is a schematic diagram of an adsorption refrigerator during a first operation. FIG. 3 is a schematic diagram of an adsorption refrigerator during a second operation. FIG. 4 is a table showing the element ratios of C, N, O, and C / N, and the pore volume ratios for materials A to D. FIG. 5 is a graph showing the adsorption isotherm of water vapor for material A. FIG. 6 is a graph showing the adsorption isotherm of water vapor for material B. FIG. 7 is a graph showing the adsorption isotherm of water vapor for materials C and D. FIG. 8 is a graph showing the adsorption isotherm of water vapor for silica gel. FIG. 9 is a graph showing the adsorption isotherm of water vapor for material E. FIG. 10 is a graph showing the adsorption isotherm of water vapor for material F. FIG. 11 is a graph showing the adsorption isotherm of water vapor for material G.

[0026] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical concept of the present disclosure. Since the drawings are intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding.

[0027] <<Embodiment>> (1) Overall Configuration An adsorption chiller (10) according to an embodiment performs an adsorption heat pump cycle. The adsorption chiller (10) of this example performs a single-stage adsorption heat pump cycle. In the single-stage adsorption heat pump cycle, a working medium is subjected to a single-stage adsorption operation and a single-stage regeneration operation.

[0028] The adsorption chiller (10) cools objects in a data center. The data center is a building that houses electronic devices (E) that are objects to be cooled by the adsorption chiller (10). The electronic devices (E) include server devices, communication devices, and the like.

[0029] As shown in FIG. 1, a data center is provided with a first server rack (S1) and a second server rack (S2). The first server rack (S1) and the second server rack (S2) are provided with server devices, which are electronic devices. The first server rack (S1) is a low-heat-generating server rack, and the second server rack (S2) is a high-heat-generating server rack. The temperature of the first server rack (S1) is lower than the temperature of the second server rack (S2). The adsorption chiller (10) cools the electronic devices (E) of the first server rack (S1). The adsorption chiller (10) regenerates the adsorbent (24) of the adsorber (20) by utilizing the exhaust heat of the second server rack (S2).

[0030] The adsorption chiller (10) is provided with cooling towers. The adsorption chiller (10) of the example shown in FIG. 1 is provided with a first cooling tower (C1), a second cooling tower (C2), and a third cooling tower (C3). These cooling towers (C1, C2, C3) cool a predetermined heat medium (water) using outside air. These cooling towers (C1, C2, C3) may be configured as a single cooling tower.

[0031] (2) Detailed Configuration The adsorption chiller (10) uses water as a working medium. The adsorption chiller (10) of this example includes two adsorbers (20), an evaporator (40), a condenser (50), and a pressure reducing valve (66). The two adsorbers (20) are composed of a first adsorber (21) and a second adsorber (31).

[0032] (2-1) Adsorption Device The first adsorption device (21) has a first adsorption chamber (22) and a first adsorption coil (23) disposed in the first adsorption chamber (22). The first adsorption device (21) in this example is a filled type in which the first adsorption chamber (22) is filled with an adsorbent (24). In the first adsorption device (21), the adsorbent (24) is provided around the first adsorption coil (23). The first adsorption coil (23) exchanges heat between the water flowing therethrough and the adsorbent (24).

[0033] The second adsorber (31) has a second adsorption chamber (32) and a second adsorption coil (33) disposed in the second adsorption chamber (32). The second adsorber (31) in this example is of a packed type in which the second adsorption chamber (32) is packed with the adsorbent (24). In the second adsorber (31), the adsorbent (24) is provided around the second adsorption coil (33). The second adsorption coil (33) exchanges heat between the water flowing therethrough and the adsorbent (24).

[0034] One of the first adsorption device (21) and the second adsorption device (31) performs an adsorption operation, and the other performs a regeneration operation. In the adsorption operation, water is adsorbed by the adsorbent (24). In the regeneration operation, the water adsorbed by the adsorbent (24) is desorbed (desorbed). The first adsorption device (21) and the second adsorption device (31) alternate between a regeneration operation and an adsorption operation. Specifically, the adsorption chiller (10) alternates between a first operation and a second operation. In the first operation, the first adsorption device (21) performs an adsorption operation, and the second adsorption device (31) performs a regeneration operation. In the second operation, the first adsorption device (21) performs a regeneration operation, and the second adsorption device (31) performs an adsorption operation.

[0035] (2-2) Evaporator The evaporator (40) cools an object. The evaporator (40) has an evaporation chamber (41) and an evaporation coil (42) arranged in the evaporation chamber (41). The evaporator (40) is provided with a spray mechanism (not shown) that sprays water accumulated at the bottom of the evaporation chamber (41) toward the evaporation coil (42). The evaporation coil (42) exchanges heat between the water sprayed from the spray mechanism and a first heat medium inside the evaporation coil (42). The first heat medium is an object to be cooled by the evaporator (40), and is water in this example.

[0036] The evaporator (40) is connected to the adsorber (20) that is in the adsorption operation. When the adsorber (20) adsorbs water in the air (water vapor), the pressure in the evaporation chamber (41) decreases. This allows the first heat medium to be cooled by utilizing the latent heat of evaporation of the water in the evaporation chamber (41).

[0037] A first cooling circuit (43) is connected to the evaporation coil (42). A first pump (P1) is connected to the first cooling circuit (43). The first pump (P1) circulates water in the first cooling circuit (43). The inlet end of the first cooling circuit (43) is connected to one end of the evaporation coil (42), and the outlet end of the first cooling circuit (43) is connected to the other end of the evaporation coil (42). The first cooling circuit (43) is connected to a flow path (not shown) for cooling the first server rack (S1). The first heat medium of the first cooling circuit (43) cools the electronic equipment (E) of the first server rack (S1).

[0038] (2-3) Condenser The condenser (50) cools and condenses water vapor. The condenser (50) has a condensation chamber (51) and a condensation coil (52) arranged in the condensation chamber (51). The condensation coil (52) exchanges heat between the water vapor in the condensation chamber (51) and the second heat medium inside the condensation coil (52). The second heat medium is a heat medium cooled by the first cooling tower (C1), and is water in this example.

[0039] The condenser (50) is connected to the adsorber (20) undergoing regeneration. The water vapor desorbed from the adsorbent (24) of the adsorber (20) is cooled and condensed by the condenser (50). The condensed water accumulates at the bottom of the condensation chamber (51).

[0040] A second cooling circuit (53) is connected to the condenser (50). A second pump (P2) is connected to the second cooling circuit (53). The second pump (P2) circulates water in the second cooling circuit (53). An inlet end of the second cooling circuit (53) is connected to one end of the condensation coil (52), and an outlet end of the second cooling circuit (53) is connected to the other end of the condensation coil (52). The second cooling circuit (53) is thermally connected to the first cooling tower (C1). The second heat medium in the second cooling circuit (53) is cooled by the first cooling tower (C1).

[0041] (2-4) Main Circuit The adsorption chiller (10) has a main circuit (60) through which the working medium flows. The main circuit (60) includes a first evaporation side flow path (61), a second evaporation side flow path (62), a first condensation side flow path (63), a second condensation side flow path (64), and a relay flow path (65).

[0042] An inflow end of the first evaporation side flow path (61) is connected to the evaporation chamber (41) of the evaporator (40), and an outflow end of the first evaporation side flow path (61) is connected to the first adsorption chamber (22) of the first adsorption device (21). An inflow end of the second evaporation side flow path (62) is connected to the evaporation chamber (41) of the evaporator (40), and an outflow end of the second evaporation side flow path (62) is connected to the second adsorption chamber (32) of the second adsorption device (31). A first on-off valve (V1) is provided in the first evaporation side flow path (61), and a second on-off valve (V2) is provided in the second evaporation side flow path (62).

[0043] An inflow end of the first condensation side flow path (63) is connected to the first adsorption chamber (22) of the first adsorber (21), and an outflow end of the first condensation side flow path (63) is connected to the condensation chamber (51) of the condenser (50). An inflow end of the second condensation side flow path (64) is connected to the second adsorption chamber (32) of the second adsorber (31), and an outflow end of the second condensation side flow path (64) is connected to the condensation chamber (51) of the condenser (50). A third on-off valve (V3) is provided in the first condensation side flow path (63), and a fourth on-off valve (V4) is provided in the second condensation side flow path (64).

[0044] The inlet end of the relay flow path (65) is connected to the bottom of the condensation chamber (51) of the condenser (50). The outlet end of the relay flow path (65) is connected to the evaporation chamber (41) of the evaporator (40). The relay flow path (65) is provided with a pressure reducing valve (66) which is a pressure reducing mechanism. The pressure reducing valve (66) reduces the pressure of the working medium flowing through the relay flow path (65).

[0045] (2-5) Adsorption-Side Circuit The adsorption chiller (10) has an adsorption-side circuit (70) for cooling the adsorbent (24) of the adsorber (20). Water flows through the adsorption-side circuit (70) as a third heat medium. The adsorption-side circuit (70) includes an adsorption-side inlet channel (71), a first flow path (72), a second flow path (73), a third flow path (74), a fourth flow path (75), and an adsorption-side outlet channel (76).

[0046] The inlet end of the adsorption-side inlet channel (71) is connected to the second cooling tower (C2). The inlet end of the first flow path (72) and the inlet end of the second flow path (73) are connected to the outlet end of the adsorption-side inlet channel (71). The outlet end of the first flow path (72) is connected to the first adsorption chamber (22) of the first adsorber (21). The outlet end of the second flow path (73) is connected to the second adsorption chamber (32) of the second adsorber (31). The inlet end of the third flow path (74) is connected to the first adsorption chamber (22) of the first adsorber (21). The inlet end of the fourth flow path (75) is connected to the second adsorption chamber (32) of the second adsorber (31). The outlet end of the third flow path (74) and the outlet end of the fourth flow path (75) are connected to the inlet end of the adsorption-side outlet channel (76). The outlet end of the adsorption side outlet channel (76) is connected to the second cooling tower (C2).

[0047] The adsorption-side inlet channel (71) is provided with a third pump (P3). The third pump (P3) circulates water in the adsorption-side circuit (70). The first flow path (72) is provided with a fifth on-off valve (V5). The second flow path (73) is provided with a sixth on-off valve (V6). The third flow path (74) is provided with a seventh on-off valve (V7). The fourth flow path (75) is provided with an eighth on-off valve (V8).

[0048] (2-6) Regeneration Side Circuit The adsorption chiller (10) has a regeneration side circuit (80) for heating and regenerating the adsorbent (24) of the adsorber (20). Water flows through the regeneration side circuit (80) as a fourth heat medium. The regeneration side circuit (80) includes a regeneration side inlet channel (81), a fifth flow path (82), a sixth flow path (83), a seventh flow path (84), an eighth flow path (85), and a regeneration side outlet channel (86).

[0049] The inlet end of the regeneration-side inlet channel (81) is connected to one end of a channel (not shown) that absorbs heat from the second server rack (S2). The inlet end of the fifth channel (82) and the inlet end of the sixth channel (83) are connected to the outlet end of the regeneration-side inlet channel (81). The outlet end of the fifth channel (82) is connected to the first adsorption chamber (22) of the first adsorber (21). The outlet end of the sixth channel (83) is connected to the second adsorption chamber (32) of the second adsorber (31). The inlet end of the seventh channel (84) is connected to the first adsorption chamber (22) of the first adsorber (21). The inlet end of the eighth channel (85) is connected to the second adsorption chamber (32) of the second adsorber (31). The outlet ends of the seventh channel (84) and the eighth channel (85) are connected to the inlet end of the regeneration-side outlet channel (86). The outlet end of the regeneration side outlet channel (86) is connected to the other end of the channel that absorbs heat from the second server rack (S2).

[0050] The regeneration side inlet channel (81) is provided with a fourth pump (P4). The fifth flow channel (82) is provided with a ninth on-off valve (V9). The sixth flow channel (83) is provided with a tenth on-off valve (V10). The seventh flow channel (84) is provided with an eleventh on-off valve (V11). The eighth flow channel (85) is provided with a twelfth on-off valve (V12).

[0051] The regeneration side outlet channel (86) is connected to a third cooling tower (C3). The third cooling tower (C3) cools the water before it flows into the second server rack (S2).

[0052] (3) Operation The operation of the adsorption chiller (10) will be described with reference to Figures 2 and 3. The adsorption chiller (10) alternately performs a first operation and a second operation. In Figures 2 and 3, open valves are indicated by outlined marks, and closed valves are indicated by outlined marks.

[0053] (3-1) First Operation In the first operation shown in Fig. 2, the first on-off valve (V1), the fourth on-off valve (V4), the fifth on-off valve (V5), the seventh on-off valve (V7), the tenth on-off valve (V10), and the twelfth on-off valve (V12) are in an open state, and the second on-off valve (V2), the third on-off valve (V3), the sixth on-off valve (V6), the eighth on-off valve (V8), the ninth on-off valve (V9), and the eleventh on-off valve (V11) are in a closed state. The pressure reducing valve (66) is adjusted to a predetermined opening. The first pump (P1), the second pump (P2), and the third pump (P3) are operated.

[0054] In the first operation, the heat medium cooled by the first cooling tower (C1) is sent to the condensing coil (52). The heat medium cooled by the second cooling tower (C2) is sent to the first adsorption coil (23) of the first adsorber (21). The heat medium heated by the second server rack (S2) is sent to the second adsorption coil (33) of the second adsorber (31). The heat medium cooled by the evaporator coil (42) is sent to the first server rack (S1). In the first operation, the first adsorber (21) performs an adsorption operation, and the second adsorber (31) performs a regeneration operation.

[0055] When the first on-off valve (V1) is opened, the evaporation chamber (41) and the first adsorption chamber (22) are in communication with each other. As a result, water evaporated in the evaporator (40) is adsorbed by the adsorbent (24) of the first adsorption device (21). In the first adsorption device (21), the heat of adsorption generated in the adsorbent (24) is cooled by the heat medium flowing through the first adsorption coil (23).

[0056] In the second adsorber (31), the adsorbent (24) is heated by the heat medium flowing through the second adsorption coil (33). As a result, water is desorbed from the adsorbent (24). When the fourth on-off valve (V4) is opened, the second adsorption chamber (32) and the condensation chamber (51) are in communication with each other. Therefore, the water desorbed from the adsorbent (24) of the second adsorber (31) is cooled by the condenser (50).

[0057] The water condensed in the condenser (50) is reduced in pressure by a pressure reducing valve (66) and then sent to the evaporator (40). In the evaporator (40), the heat medium evaporates, thereby cooling the heat medium in the evaporation coil (42). The water evaporated in the evaporation chamber (41) is sent again to the first adsorption device (21).

[0058] (3-2) Second Operation In the second operation shown in Fig. 3, the first on-off valve (V1), the fourth on-off valve (V4), the fifth on-off valve (V5), the seventh on-off valve (V7), the tenth on-off valve (V10), and the twelfth on-off valve (V12) are closed, and the second on-off valve (V2), the third on-off valve (V3), the sixth on-off valve (V6), the eighth on-off valve (V8), the ninth on-off valve (V9), and the eleventh on-off valve (V11) are open. The pressure reducing valve (66) is adjusted to a predetermined opening. The first pump (P1), the second pump (P2), and the third pump (P3) are operated.

[0059] In the second operation, the heat medium cooled by the first cooling tower (C1) is sent to the condensing coil (52). The heat medium cooled by the second cooling tower (C2) is sent to the second adsorption coil (33) of the second adsorber (31). The heat medium heated by the second server rack (S2) is sent to the first adsorption coil (23) of the first adsorber (21). The heat medium cooled by the evaporation coil (42) is sent to the first server rack (S1). In the second operation, the first adsorber (21) performs a regeneration operation, and the second adsorber (31) performs an adsorption operation.

[0060] When the second on-off valve (V2) is opened, the evaporation chamber (41) and the second adsorption chamber (32) are in communication with each other. As a result, the water evaporated in the evaporator (40) is adsorbed by the adsorbent (24) of the second adsorption device (31). In the second adsorption device (31), the heat of adsorption generated in the adsorbent (24) is cooled by the heat medium flowing through the second adsorption coil (33).

[0061] In the first adsorber (21), the adsorbent (24) is heated by the heat medium flowing through the first adsorption coil (23). As a result, water is desorbed from the adsorbent (24). When the third on-off valve (V3) is opened, the first adsorption chamber (22) and the condensation chamber (51) are in communication with each other. Therefore, the water desorbed from the adsorbent (24) of the first adsorber (21) is cooled by the condenser (50).

[0062] The water condensed in the condenser (50) is reduced in pressure by a pressure reducing valve (66) and then sent to the evaporator (40). In the evaporator (40), the heat medium evaporates, thereby cooling the heat medium in the evaporation coil (42). The water evaporated in the evaporation chamber (41) is sent again to the second adsorption device (31).

[0063] (4) Temperature Conditions The temperature conditions during operation of the adsorption chiller (10) will be described.

[0064] The regeneration temperature of the adsorbent (24) of the adsorber (20) is 45° C. or higher and 60° C. or lower. Specifically, the temperature T1 of the heat medium flowing out from the second server rack (S2) to the regeneration-side inlet channel (81) is 45° C. or higher and 60° C. or lower. The temperature T1 corresponds to the exhaust heat temperature of the second server rack (S2). The heat medium at the temperature T1 is supplied to the adsorber (20) and used for regenerating the adsorbent (24).

[0065] The evaporator (40) cools the heat medium to a predetermined temperature in the range of 20° C. to 25° C. Specifically, the temperature T2 of the first heat medium after being cooled by the evaporation coil (42) of the first cooling circuit (43) is 20° C. to 25° C. This heat medium is used to cool a first server rack (S1) including electronic devices (E).

[0066] In the first cooling tower (C1), the second cooling tower (C2), and the third cooling tower (C3), the heat medium is cooled to the outside air temperature (for example, 30°C).

[0067] (5) Adsorbent As described above, the regeneration temperature of the adsorbent (24) of the adsorption chiller (10) of this embodiment is 45°C or higher and 60°C or lower. This regeneration temperature is lower than the general regeneration temperature (e.g., 80°C) of a conventional example. For this reason, if a conventional adsorbent (e.g., silica gel) is used, the adsorption-type heat pump cycle as described above in the adsorption chiller cannot be operated sufficiently, or the efficiency of the COP (coefficient of performance) and the like decreases. Therefore, in this embodiment, the following material A or material B is used as the adsorbent (24) of the adsorber (20).

[0068] (5-1) C / N and Pore Volume Ratio Figure 4 shows the properties of materials A and B of this embodiment and comparative materials C and D. The data in Figures 4 to 7 shown below are based on the following source documents.

[0069] Source: Janina Kossmann, Regina Rothe, Tobias Heil, Markus Antonietti, Nieves Lopez-Salas, Ultrahigh water sorption on highly nitrogen-doped carbonaceous materials derived from uric acid, Journal of Colloid and Interface Science 602, 2021, pages 883-885. Materials A, B, C, and D are carbon materials derived from uric acid and contain nitrogen. Materials A, B, C, and D all have a porous structure with numerous pores. Materials A, B, C, and B have numerous pores (mesopores) with diameters of 2 nm to 50 nm.

[0070] Materials A, B, C, and D are obtained by the following procedure: First, 1 g of uric acid is dissolved in 5 g of NaCl and 5 g of ZnCl. ２ The mixture is prepared by mixing the above ingredients. The mixture is transferred to a crucible and heat-treated in a nitrogen atmosphere at a heating rate of 1°C / min. Material A is heat-treated to a final temperature of 750°C. Material B is heat-treated to a final temperature of 800°C. Material C is heat-treated to a final temperature of 500°C. Material D is heat-treated to a final temperature of 700°C. For uric acid-derived carbon materials, the heat treatment temperature is preferably 700°C or higher. After the heat treatment, the materials are washed with hydrochloric acid and then dried at 70°C for 3 hours to obtain each material.

[0071] The elemental composition of each material in Fig. 4 was measured by EDX (energy dispersive X-ray fluorescence spectrometry). The elemental ratio of carbon to nitrogen (C / N) in Fig. 4 was measured by ECA (elemental chemical analysis). The C / N [%] was 2.6 for material A, 6.2 for material B, 1.1 for material C, and 1.8 for material D. Therefore, it is preferable that the adsorbent (24) have a C / N of greater than 1.8.

[0072] The volume ratio of pores in each material in Figure 4 is the ratio of the total volume Vt of pores (mesopores) with a diameter of 2 nm to 50 nm to the total weight wt of the material (α = Vt / wt [cm 3 / g]). The pore volume ratios are 0.76 for material A, 1.75 for material B, 0.00 for material C, and 0.32 for material D. Therefore, it is preferable that the pore volume ratio of the adsorbent (24) is greater than 0.32.

[0073] (5-2) Effective Adsorption Amount In the above-described embodiment, the regeneration temperature of the adsorbent (24) is 45°C or higher and 60°C or lower, and the evaporator (40) cools the heat transfer medium to 20°C or higher and 25°C or lower. It has been found that under these operating conditions, if the adsorbent (24) has high adsorption performance within a relative humidity range of 30% to 66%, the adsorption chiller (10) can be operated efficiently. Therefore, in this embodiment, the adsorbent (24) has a difference in the amount of water adsorbed within a relative humidity range of 30% to 66% (hereinafter, this difference is also referred to as effective adsorption amount) of greater than 0.17 g / g. The adsorption amount here refers to the amount of water that the adsorbent (24) can adsorb per unit weight.

[0074] Fig. 5 shows the adsorption isotherm of material A at a typical temperature (25°C). Material A is configured so that the relationship between relative humidity and adsorption amount in the adsorption process (solid line in Fig. 5) differs from the relationship between relative humidity and adsorption amount in the desorption process (dashed line in Fig. 5). Note that for material A, the relationship between relative humidity and adsorption amount does not change significantly with temperature.

[0075] When water is adsorbed and desorbed in material A at a relative humidity range of 30% to 66%, the relative humidity and adsorption amount change in the order of a1, a2, a3, a4, and a1. Between a4 and a1, the amount of adsorbed water does not change even when the relative humidity increases as the water vapor cools. Between a1 and a2, the adsorption process is performed in the adsorbent (24), and the amount of adsorbed water increases as the relative humidity increases. Between a2 and a3, the amount of adsorbed water does not change even when the relative humidity decreases as the water vapor heats. Between a3 and a4, the desorption process is performed in the adsorbent (24), and the amount of adsorbed water decreases as the relative humidity decreases.

[0076] For material A, the difference (ΔW) between the first adsorption amount (w1), which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 30%, and the second adsorption amount (w2), which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66%, is 0.3 [g / g]. As described above, material A has different characteristics (so-called hysteresis) in the adsorption process and the desorption process. Strictly speaking, the first adsorption amount (w1) here is the amount of water adsorbed at a target air temperature of 25°C and a relative humidity of 30% during the desorption process. Strictly speaking, the second adsorption amount (w2) is the amount of water adsorbed at a target air temperature of 25°C and a relative humidity of 66% during the adsorption process.

[0077] Fig. 6 shows the adsorption isotherm of material B at a typical temperature (25°C). Material B is configured so that the relationship between relative humidity and adsorption amount in the adsorption step (solid line in Fig. 6) differs from the relationship between relative humidity and adsorption amount in the desorption step (dashed line in Fig. 6). Note that for material B, the relationship between relative humidity and adsorption amount does not change significantly with temperature.

[0078] When water is adsorbed and desorbed in material B at a relative humidity range of 30% to 66%, the relative humidity and the amount of adsorption change in the order of b1, b2, and b3, for example. Between b1 and b2, the adsorption process is performed in the adsorbent (24), and the amount of adsorbed water increases as the relative humidity increases. Between b2 and b3, the amount of adsorbed water does not change even if the relative humidity decreases as the water vapor is heated. Between b3 and b1, the desorption process is performed in the adsorbent (24), and the amount of adsorbed water decreases as the relative humidity decreases.

[0079] For material B, the difference (ΔW) between the first adsorption amount (w1), which is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 30%, and the second adsorption amount (w2), which is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 66%, is 0.45 [g / g]. Strictly speaking, the first adsorption amount (w1) here is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 30% during the desorption step. Strictly speaking, the second adsorption amount (w2) is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 66% during the adsorption step.

[0080] Figure 7 shows the adsorption isotherms of materials C and D for comparison at a typical temperature (25°C). These are adsorption isotherms at room temperature (25°C). In Figure 7, for materials C and D, the adsorption isotherms for the adsorption process are shown by solid lines, and the adsorption isotherms for the desorption process are shown by dashed dotted lines. For materials C and D, ΔW is extremely low in the relative humidity range of 30% to 66%, not even reaching 0.1 [g / g].

[0081] Figure 8 shows the water vapor adsorption isotherm of silica gel, a common adsorbent. The data in Figure 8 is based on the following source:

[0082] Source: Masaya Suzuki, Journal of the Society of Inorganic Materials, Japan 14, (2007). Note that the adsorption isotherms of silica gel are substantially equal in the adsorption and desorption processes, and exhibit no hysteresis. As can be seen from Figure 8, the difference (ΔW) between the first adsorption amount (w1), which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 30%, and the second adsorption amount (w2), which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66%, is approximately 0.17 g / g.

[0083] Thus, the effective adsorption amount ΔW of the adsorbent (24) in the relative humidity range of 30% to 66% is preferably greater than 0.17, which corresponds to silica gel, more preferably 0.3 or more, and even more preferably 0.45 or more.

[0084] The refrigeration capacity Q of the adsorption chiller (10) is expressed by the following equation (1).

[0085] Refrigeration capacity Q=M×L×ΔW (1) where M is the total dry weight of the adsorbent (24), L is the latent heat of vaporization of water vapor in the evaporator (40), and ΔW is the difference between the first adsorption amount and the second adsorption amount (effective adsorption amount). In this embodiment, the effective adsorption amount is large in the relative humidity range of 30% to 66%, so that high refrigeration capacity can be obtained under operating conditions where the regeneration temperature is relatively low.

[0086] (6) Effects of the Embodiment The adsorbent (24) of the adsorption chiller (10) has a difference of more than 0.17 g / g between a first adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 30%, and a second adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66%. Strictly speaking, material A and material B are configured to have different characteristics in the relationship between the relative humidity and the adsorption amount during the adsorption process and the relationship between the relative humidity and the adsorption amount during the desorption process. The first adsorption amount is the amount of water adsorbed when the target air temperature is 25°C and a relative humidity of 30% during the desorption process, and the second adsorption amount is the amount of water adsorbed when the target air temperature is 25°C and a relative humidity of 66% during the adsorption process.

[0087] The adsorbent (24) of this embodiment has a large effective adsorption amount ΔW under operating conditions with a relatively low regeneration temperature, in other words, under a relatively high relative humidity range. This makes it possible to prevent the performance of the adsorbent (24) from deteriorating under operating conditions with a relatively low regeneration temperature. As a result, it is possible to prevent the adsorption heat pump cycle from becoming inoperable and the efficiency of the COP and the like from deteriorating.

[0088] In particular, when the regeneration temperature of the adsorbent (24) is 45°C or higher and 60°C or lower, and further when the evaporator (40) cools the object to 20°C or higher and 25°C or lower, the adsorbent (24) of the present disclosure is suitable for obtaining a high refrigeration capacity.

[0089] Additionally, the adsorbent (24) of the present disclosure is suitable for cooling electronic devices (E).

[0090] Furthermore, materials A and B, which are adsorbents (24) of the present disclosure, contain carbon, nitrogen, and oxygen, have an elemental ratio of carbon to nitrogen greater than 1.8, and have a pore structure with a large number of pores, and the ratio of the total volume of pores with diameters of 2 nm or more and 50 nm or less to the weight of the material is 0.32 cm 3 / g or more (see FIG. 4). Therefore, as shown in FIG. 5, a high effective adsorption amount can be obtained in the relative humidity range of 30% to 66%. Therefore, under the operating conditions of this embodiment, a particularly high refrigeration capacity can be obtained.

[0091] The adsorption chiller (10) of this embodiment is a single-stage type, yet can obtain a high refrigeration capacity. Therefore, compared with an adsorption chiller that performs a multi-stage adsorption heat pump cycle, the device can be made smaller, simpler, and less expensive. Here, a multi-stage adsorption chiller performs an adsorption operation and a regeneration operation for each of two or more stages of adsorbers (20).

[0092] (7) Modifications The above-described embodiment may be modified.

[0093] (7-1) Modification 1 The adsorbent (24) of Modification 1 is composed of a material containing a metal-organic framework (MOF). The adsorbent (24) containing the metal-organic framework has a large difference (effective adsorption amount ΔW) of 0.17 [g / g] between a first adsorption amount (w1), which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 30%, and a second adsorption amount (w2), which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66%. Examples of such an adsorbent (24) include Material E and Material F.

[0094] Material E is named Ni2Cl2(BTDD), and its chemical compound name is catena-(bis(m-chloro)-(m-2H,8H-[1,2,3]triazolo[4',5':7,8]oxanthreno[2,3-d][1,2,3]triazole)-diaqua-di-nickel), and its chemical formula is C １２ H ８ Cl ２ Ni ２ N ６ O ４ is.

[0095] Fig. 9 shows the adsorption isotherm of material E at a typical temperature (25°C). Material E is configured so that the relationship between relative humidity and adsorption amount in the adsorption process (solid line in Fig. 9) differs from the relationship between relative humidity and adsorption amount in the desorption process (dashed line in Fig. 9). Note that for material E, the relationship between relative humidity and adsorption amount does not change significantly with temperature.

[0096] For material E, the difference (ΔW) between the first adsorption amount (w1), which is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 30%, and the second adsorption amount (w2), which is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 66%, is 0.25 [g / g]. Strictly speaking, the first adsorption amount (w1) here is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 30% during the desorption step. Strictly speaking, the second adsorption amount (w2) is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 66% during the adsorption step.

[0097] Material F is named MIL-101-Cr, and its chemical compound name is catena-[tris(μ4-Terephthalato)-(μ3-oxo)-diaqua-fluoro-tri-chromium pentadecahydrate], and its chemical formula is C ２４ H １７ O １６ Cr ３ is.

[0098] Fig. 10 shows the adsorption isotherm of material F at a typical temperature (25°C). Material F is configured so that the relationship between relative humidity and adsorption amount in the adsorption process (solid line in Fig. 10) differs from the relationship between relative humidity and adsorption amount in the desorption process (dashed line in Fig. 10). Note that for material F, the relationship between relative humidity and adsorption amount does not change significantly with temperature.

[0099] For material F, the difference (ΔW) between the first adsorption amount (w1), which is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 30%, and the second adsorption amount (w2), which is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 66%, is 0.7 g / g. Strictly speaking, the first adsorption amount (w1) here is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 30% during the desorption step. Strictly speaking, the second adsorption amount (w2) is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 66% during the adsorption step.

[0100] As described above, the materials E and F have a large effective adsorption amount ΔW under the operating condition of a relatively low regeneration temperature, in other words, under the relatively high relative humidity range. Therefore, it is possible to suppress a decrease in the performance of the adsorbent (24) under the operating condition of a relatively low regeneration temperature. As a result, it is possible to suppress a failure to operate the adsorption heat pump cycle and a decrease in the efficiency of the COP and the like.

[0101] The maximum pore diameter of the metal organic framework of Modification 1 is preferably 6 Å (angstroms) or more. The volume ratio of the pores in the metal organic framework (the ratio of the total volume Vt of the pores to the total weight wt of the material) is preferably 0.50 or more. The element ratio (C / N) of the metal organic framework is preferably 1.8 or more.

[0102] (7-2) Modification 2 The adsorbent (24) of Modification 2 is composed of a material containing a metal-organic framework (MOF). The adsorbent (24) containing the metal-organic framework has a difference (ΔW′) between a third adsorption amount (w3), which is the amount of water adsorbed at a temperature of 60° C. and a relative humidity of 30% during the desorption step, and a fourth adsorption amount (w4), which is the amount of water adsorbed at a temperature of 25° C. and a relative humidity of 66% during the adsorption step, that is greater than 0.17 [g / g]. An example of such an adsorbent (24) is Material G.

[0103] Material G has the name CAU-23-Al, the chemical compound name is catena-[octakis(m-thiophene-2,5-dicarboxylato)-octakis(m-hydroxo)-octa-aluminum(iii)dotriacontahydrate], and the chemical formula is C ４８ H ２４ Al ８ O ４０ S ８ is.

[0104] FIG. 11 shows the adsorption isotherms of material G at 25°C and material G at 60°C. Material G has temperature dependence, and its adsorption / desorption characteristics change significantly depending on the temperature. The adsorption isotherm of material G shifts downward and to the right as the temperature increases. In other words, material G is configured so that the amount of water adsorbed decreases as the temperature increases. Note that, in general, adsorbents have the same temperature dependence as material G, but, like material E, their adsorption isotherms do not change significantly with temperature. In addition, material G is configured so that, at temperatures of 25°C and 60°C, the relationship between relative humidity and adsorption amount in the adsorption process (solid line in FIG. 11 ) and the relationship between relative humidity and adsorption amount in the desorption process (dashed line in FIG. 11 ) have different characteristics.

[0105] For material G, the difference ΔW' between the third adsorption amount (w3), which is the amount of water adsorbed at a temperature of 60°C and a relative humidity of 30% during the desorption step, and the fourth adsorption amount (w4), which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66% during the adsorption step, is 0.35 [g / g]. As described above, the regeneration temperature of the adsorbent (24) of the adsorption chiller (10) is 45°C or higher and 60°C or lower. Therefore, it can be said that the third adsorption amount (w3) is the adsorption amount that is closest to the actual operating conditions of the adsorption chiller (10).

[0106] As described above, the material G has a large effective adsorption amount ΔW' under operating conditions with a relatively low regeneration temperature, in other words, under a relatively high relative humidity range. Therefore, it is possible to prevent the performance of the adsorbent (24) from deteriorating under operating conditions with a relatively low regeneration temperature. As a result, it is possible to prevent the adsorption heat pump cycle from becoming inoperable and the efficiency of the COP and the like from deteriorating.

[0107] The maximum pore diameter of the metal organic framework of Modification 2 is preferably 6 Å (angstroms) or more. The volume ratio of the pores in the metal organic framework (the ratio of the total volume Vt of the pores to the total weight wt of the material) is preferably 0.50 or more. The element ratio (C / N) of the metal organic framework is preferably 1.8 or more.

[0108] (8) Other Embodiments The above-described embodiments and modifications may be configured as follows.

[0109] The adsorber (20) may be an adsorption heat exchanger type having an adsorption coil and a number of fins through which the adsorption coil passes, with the adsorbent (24) provided on the surfaces of the fins.

[0110] The adsorption chiller (10) may be an intermittent batch type in which one adsorber (20) intermittently performs adsorption and regeneration operations.

[0111] The adsorption chiller (10) may have three or more adsorbers (20), and may be of a type in which some of the adsorbers (20) perform adsorption operation and the remaining ones perform regeneration operation.

[0112] The adsorption chiller (10) may be a multi-stage type in which the adsorption operation and the regeneration operation are performed in two or more stages of adsorbers (20) respectively.

[0113] The adsorbent (24) may be made of other materials as long as they satisfy the various conditions described above.

[0114] Although the embodiments and modifications have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, elements of the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate.

[0115] The above-mentioned descriptions such as "first," "second," "third," etc. are used to distinguish the words to which these descriptions are attached, and do not limit the number or order of the words.

[0116] As described above, the present disclosure is useful for adsorption refrigerators.

[0117] 10 Adsorption refrigerator 20 Adsorber 24 Adsorbent 40 Evaporator 50 Condenser E Electronic equipment

Claims

1. An adsorption chiller that performs an adsorption heat pump cycle and includes an adsorber (20), an evaporator (40), and a condenser (50), each having an adsorbent (24) that adsorbs water, wherein the difference between a first adsorption amount, which is the amount of water adsorbed by the adsorbent (24) at a temperature of 25°C and a relative humidity of 30%, and a second adsorption amount, which is the amount of water adsorbed by the adsorbent (24) at a temperature of 25°C and a relative humidity of 66%, is greater than 0.17 [g / g].

2. The adsorption chiller according to claim 1, wherein the adsorbent (24) is configured so that the relationship between the relative humidity and the adsorption amount in the adsorption process is different from the relationship between the relative humidity and the adsorption amount in the desorption process, the first adsorption amount being the amount of water adsorbed when the target air temperature is 25°C and the relative humidity is 30% in the desorption process, and the second adsorption amount being the amount of water adsorbed when the target air temperature is 25°C and the relative humidity is 66% in the adsorption process.

3. The adsorption chiller according to claim 1 or 2, wherein the regeneration temperature of the adsorbent (24) of the adsorber (20) is 45°C or higher and 60°C or lower.

4. The adsorption chiller according to any one of claims 1 to 3, wherein the evaporator (40) cools an object to a temperature of 20°C or higher and 25°C or lower.

5. The adsorption chiller according to any one of claims 1 to 4, wherein an electronic device (E) is cooled by the heat medium as the object cooled by the evaporator (40).

6. The adsorbent (24) contains carbon, nitrogen, and oxygen, the element ratio of the carbon to the nitrogen is greater than 1.8, and has a porous structure with a large number of pores, and the ratio of the total volume of pores with a diameter of 2 nm to 50 nm to the weight of the adsorbent (24) is 0.32 cm 3 The adsorption refrigerator according to any one of claims 1 to 5, wherein the adsorption efficiency is 1 / g or more.

7. The adsorption refrigerator according to any one of claims 1 to 5, wherein the adsorbent (24) contains a metal organic framework.

8. The adsorption chiller according to any one of claims 1 to 7, which operates as a single-stage adsorption heat pump cycle.

9. An adsorption chiller having an adsorber (20), an evaporator (40), and a condenser (50), each having an adsorbent (24) that adsorbs water, and performing an adsorption heat pump cycle, wherein the adsorbent (24) is configured to have characteristics such that the relationship between the relative humidity and the adsorption amount in the adsorption process is different from the relationship between the relative humidity and the adsorption amount in the desorption process, and the adsorbent (24) has a third adsorption amount, which is the amount of water adsorbed at a temperature of 60°C and a relative humidity of 30% in the desorption process, and a fourth adsorption amount, which is the amount of water adsorbed at a temperature of 25°C and a relative humidity of 66% in the adsorption process, that is greater than 0.17 [g / g].

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