Heat source unit

Abstract

To restrain a decrease in the COP of a refrigeration cycle device.SOLUTION: A heat source unit of a refrigeration cycle device (1) performs cooling operation for cooling water in a water circuit (30), and comprises: a first refrigerant circuit (10A) comprising a first compressor (11A), a first air heat exchanger (12A), and a first water heat exchanger (14A) for exchanging heat between a refrigerant and the water in the water circuit (30); and a second refrigerant circuit (10B) comprising a second compressor (11B), a second air heat exchanger (12B), and a second water heat exchanger (14B) for exchanging heat between a refrigerant and the water in the water circuit (30). The water circuit (30) is constituted so that the water flows through the first water heat exchanger (14A) and the second water heat exchanger (14B) in this order during the cooling operation. The heat exchange capacity of the first air heat exchanger (12A) is larger than the heat exchange capacity of the second air heat exchanger (12B).SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a heat source unit. [Background technology]

[0002] The refrigeration system described in Patent Document 1 has multiple refrigerant circuits to which compressors are connected, and exchanges heat between the refrigerant and water flowing through two water heat exchangers connected in series. The two water heat exchangers are connected to independent refrigerant circuits as utilization heat exchangers. The capacity of the refrigeration system is controlled according to the operating load state so that the rotation speeds of the compressors connected to the two water heat exchangers are the same. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-206331 Summary of the Invention [Problem to be solved by the invention]

[0004] For example, during cooling operation to cool water in the water circuit, the water flowing through the water circuit is cooled by an upstream water heat exchanger and then further cooled by a downstream water heat exchanger. Therefore, because the water temperature in the upstream water heat exchanger is higher than that in the downstream water heat exchanger, the evaporation temperature of the refrigerant in the upstream water heat exchanger is higher than that in the downstream water heat exchanger. In other words, the low pressure in the refrigeration cycle of the refrigerant circuit connected to the upstream water heat exchanger is higher than the low pressure in the refrigeration cycle of the refrigerant circuit connected to the downstream water heat exchanger. As such, when the low pressure in the refrigeration cycle of the refrigerant circuit connected to the upstream water heat exchanger increases, the high pressure also increases, which tends to increase the input power to the compressor. This increases the compressor's power consumption and reduces the coefficient of performance (COP) of the refrigeration cycle device.

[0005] An object of the present disclosure is to suppress a decrease in the COP of a refrigeration cycle device. [Means for solving the problem]

[0006] The first aspect is A heat source unit of a refrigeration cycle device (1) that performs a cooling operation to cool water in a water circuit (30), a first refrigerant circuit (10A) including a first compressor (11A), a first air heat exchanger (12A), and a first water heat exchanger (14A) for exchanging heat between a refrigerant and water in the water circuit (30); a second refrigerant circuit (10B) including a second compressor (11B), a second air heat exchanger (12B), and a second water heat exchanger (14B) for exchanging heat between a refrigerant and water in the water circuit (30); In the cooling operation, the first water heat exchanger (14A) and the second water heat exchanger (14B) function as evaporators, and the first air heat exchanger (12A) and the second air heat exchanger (12B) function as condensers; the water circuit (30) is configured so that water flows through the first water heat exchanger (14A) and then the second water heat exchanger (14B); The heat exchange capacity of the first air heat exchanger (12A) is greater than the heat exchange capacity of the second air heat exchanger (12B).

[0007] In the cooling operation, the evaporation temperature of the first water heat exchanger (14A) is higher than that of the second water heat exchanger (14B). Therefore, as the low pressure of the first refrigerant circuit (10A) increases, the high pressure also increases accordingly. Therefore, in the first aspect, the heat exchange capacity of the first air heat exchanger (12A) is set higher than the heat exchange capacity of the second air heat exchanger (12B), thereby suppressing an increase in the high pressure of the first refrigerant circuit (10A). Suppressing the increase in the high pressure also suppresses the input to the first compressor (11A), thereby suppressing a decrease in the COP of the refrigeration cycle apparatus (1). Furthermore, in the second refrigerant circuit (10B), even if the capacity of the second air heat exchanger (12B) is reduced, the high pressure tends not to increase easily. Therefore, the size of the second air heat exchanger (12B) can be reduced. This allows the second air heat exchanger (12B) to be made smaller even if the first air heat exchanger (12A) is made larger in size to increase the capacity of the first air heat exchanger (12A), thereby preventing the entire heat source unit (U) from becoming larger.

[0008] The second aspect is the first aspect, the first air heat exchanger (12A) and the second air heat exchanger (12B) are fin-and-tube heat exchangers in which a plurality of fins (71) are arranged in a thickness direction and a heat transfer tube (72a) penetrates through the plurality of fins (71), The first air heat exchanger (12A) is more efficient than the second air heat exchanger (12B). The number of rows of the heat transfer tubes (72a) arranged in the vertical direction is large, the number of columns of the heat transfer tubes (72a) arranged in the front-to-back direction is large, the effective length of the heat transfer tubes (72a) extending in the left-to-right direction is long, or the fin pitch between adjacent fins (71) is small.

[0009] In the second aspect, the smaller the fin pitch, the greater the contact area between the air and the fins, and therefore the greater the heat dissipation capacity of the first air heat exchanger (12A). This makes it possible to make the heat exchange capacity of the first air heat exchanger (12A) greater than that of the second air heat exchanger (12B).

[0010] The third aspect is the first or second aspect, The first air heat exchanger (12A) has a heat exchange capacity 5 to 10% higher than that of the second air heat exchanger (12B).

[0011] In the third aspect, by providing a difference in capacity between the first air heat exchanger (12A) and the second air heat exchanger (12B), the COP of the refrigeration cycle apparatus (1) can be made relatively high.

[0012] The fourth aspect is A heat source unit of a refrigeration cycle device (1) that performs a cooling operation to cool water in a water circuit (30), a first refrigerant circuit (10A) including a first compressor (11A), a first air heat exchanger (12A), and a first water heat exchanger (14A) for exchanging heat between a refrigerant and water in the water circuit (30); a second refrigerant circuit (10B) including a second compressor (11B), a second air heat exchanger (12B), and a second water heat exchanger (14B) for exchanging heat between a refrigerant and water in the water circuit (30); In the cooling operation, the first water heat exchanger (14A) and the second water heat exchanger (14B) function as evaporators, and the first air heat exchanger (12A) and the second air heat exchanger (12B) function as condensers; the water circuit (30) is configured so that water flows through the first water heat exchanger (14A) and then the second water heat exchanger (14B); The heat exchange capacity of the first water heat exchanger (14A) is smaller than the heat exchange capacity of the second water heat exchanger (14B).

[0013] In the fourth aspect, by setting the heat exchange capacity of the first water heat exchanger (14A) lower than that of the second water heat exchanger (14B), it is possible to suppress an increase in the low pressure and also in the high pressure in the first refrigerant circuit (10A), thereby suppressing a decrease in the COP of the refrigeration cycle apparatus (1).

[0014] The fifth aspect is the fourth aspect, the first water heat exchanger (14A) and the second water heat exchanger (14B) are plate-type heat exchangers in which a plurality of plates (21a, 21b, 21c, 21d, 21e) are arranged in a thickness direction; The first water heat exchanger (14A) has smaller plates (21a, 21b, 21c, 21d, 21e) than the second water heat exchanger (14B), has fewer plates (21a, 21b, 21c, 21d, 21e), or has fewer or shorter water flow paths within the plates (21a, 21b, 21c, 21d, 21e).

[0015] In the fifth aspect, the heat exchange capacity of the first water heat exchanger (14A) can be set smaller than the heat exchange capacity of the second water heat exchanger (14B).

[0016] A sixth aspect is the fourth or fifth aspect, The first water heat exchanger (14A) has a heat exchange capacity 5 to 10% lower than that of the second water heat exchanger (14B).

[0017] In the sixth aspect, the high pressure of the first refrigerant circuit (10A) and the high pressure of the second refrigerant circuit (10B) can be made closer to each other during the cooling operation.

[0018] A seventh aspect is any one of the first to sixth aspects, a control unit (100) that controls the first compressor (11A) and the second compressor (11B), The control unit (100) controls the first compressor (11A) and the second compressor (11B) so that the rotation speeds of the first compressor (11A) and the second compressor (11B) are equal to each other.

[0019] In the seventh aspect, the first compressor (11A) and the second compressor (11B) have the same rotation speed, and therefore the capacity of the first refrigerant circuit (10A) is higher than that of the second refrigerant circuit (10B). However, the condensation capacity of the first air heat exchanger (12A) is greater than the condensation capacity of the second air heat exchanger (12B). Therefore, the increase in the high pressure of the first refrigerant circuit (10A) can be suppressed. As a result, the capacity of the first refrigerant circuit (10A) can be suppressed.

[0020] The eighth aspect is the seventh aspect, During operation of the refrigeration cycle apparatus (1), the control unit (100) controls the rotation speeds of the first compressor (11A) and the second compressor (11B) in accordance with the water temperature of the water circuit (30).

[0021] In the eighth aspect, the water temperature in the water circuit (30) can be maintained at the target water temperature, and a decrease in the COP of the refrigeration cycle device can be suppressed.

[0022] A ninth aspect is any one of the first to eighth aspects, a first fan (18A) that delivers air to the first air heat exchanger (12A); a second fan (18B) that transports air to the second air heat exchanger (12B); The air volume of the first fan (18A) is greater than the air volume of the second fan (18B).

[0023] In the ninth aspect, the heat exchange capacity of the first air heat exchanger (12A) can be made greater than that of the second air heat exchanger (12B).

[0024] A tenth aspect is the first aspect, the first air heat exchanger (12A) is a microchannel heat exchanger, The second air heat exchanger (12B) is a fin-and-tube heat exchanger in which a plurality of fins (71) are arranged in a thickness direction and a heat transfer tube (72a) penetrates through the plurality of fins (71), The heat transfer tubes (72a) of the second air heat exchanger (12B) are copper tubes.

[0025] In the tenth aspect, the heat exchange capacity of the first air heat exchanger (12A) can be made greater than that of the second air heat exchanger (12B).

[0026] An eleventh aspect is any one of the first to tenth aspects, The distance between the first air heat exchanger (12A) and the first water heat exchanger (14A) is shorter than the distance between the second air heat exchanger (12B) and the second water heat exchanger (14B).

[0027] In the eleventh aspect, the length of the refrigerant piping between the first air heat exchanger (12A) and the first water heat exchanger (14A) and the length of the refrigerant piping between the second air heat exchanger (12B) and the second water heat exchanger (14B) can be shortened, thereby reducing the pressure loss of the refrigerant in the first refrigerant circuit (10A), and thereby preventing a decrease in the efficiency of the cooling operation.

[0028] A twelfth aspect is the first aspect, The refrigeration cycle device (1) performs a heating operation to heat water in the water circuit (30), The heat exchange capacity of the second air heat exchanger (12B) is smaller than the heat exchange capacity of the first air heat exchanger (12A).

[0029] In the twelfth aspect, in the heating operation, the condensation temperature of the second water heat exchanger (14B) is higher than the condensation temperature of the first water heat exchanger (14A), and therefore the high pressure of the second refrigerant circuit (10B) becomes high. The high pressure of the second refrigerant circuit (10B) can be suppressed by reducing the heat exchange capacity of the second air heat exchanger (12B).

[0030] A thirteenth aspect is the first aspect, The refrigeration cycle device (1) performs a heating operation to heat water in the water circuit (30), The heat exchange capacity of the second water heat exchanger (14B) is greater than the heat exchange capacity of the first water heat exchanger (14A).

[0031] In the thirteenth aspect, during heating operation, the condensation temperature of the second water heat exchanger (14B) is higher than the condensation temperature of the first water heat exchanger (14A), and therefore, by reducing the heat exchange capacity of the second water heat exchanger (14B), the high pressure in the second refrigerant circuit (10B) can be reduced. [Brief explanation of the drawings]

[0032] [Figure 1] FIG. 1 is a piping diagram of a refrigerant circuit of a heat source unit of this embodiment. [Figure 2] FIG. 2 is a schematic diagram showing the configuration of a general plate-type water heat exchanger. [Figure 3] FIG. 3 is a schematic diagram showing a connection configuration between the first water heat exchanger and the second water heat exchanger. [Figure 4] FIG. 4 is a perspective view showing the appearance of the heat source unit. [Figure 5] FIG. 5 is a horizontal cross-sectional view of the heat source unit showing the internal configuration of the machine room. [Figure 6] FIG. 6 is a perspective view of an air heat exchanger. [Figure 7] FIG. 7 is a front view of the air heat exchanger. [Figure 8] FIG. 8 is a schematic diagram of the first air heat exchanger and the second air heat exchanger as viewed from the stacking direction of the fins. [Figure 9] FIG. 9 is a schematic diagram of the first air heat exchanger and the second air heat exchanger according to Modification 1-1, which corresponds to FIG. [Figure 10] FIG. 10 is a schematic diagram of a first air heat exchanger and a second air heat exchanger according to Modification 1-2, which corresponds to FIG. [Figure 11] FIG. 11 is a schematic diagram of a first air heat exchanger and a second air heat exchanger according to Modification 1-3, which corresponds to FIG. [Figure 12] FIG. 12 is a perspective view showing the appearance of a first air heat exchanger of the fourth modification. [Figure 13] FIG. 13 is a plan view showing a part of the first air heat exchanger cut along a horizontal plane. DETAILED DESCRIPTION OF THE INVENTION

[0033] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or its uses. Furthermore, each configuration of each embodiment, modification, other example, etc. described below can be combined or partially substituted within the scope of the present invention. In the following description, the terms "upper," "lower," "right," "left," "front," and "rear" refer to the directions described in each drawing.

[0034] (1) Overview The heat source unit (U) according to this embodiment is used as a heat source for a refrigeration cycle apparatus (1). For example, the refrigeration cycle apparatus (1) is an air conditioning apparatus that provides air conditioning for offices, shopping malls, factories, etc. The heat source unit (U) is a chilling unit dedicated to cooling that produces chilled water. The heat source unit (U) is an air-cooled chilling unit.

[0035] (2) Refrigerant circuit configuration The heat source unit (U) of this embodiment has a plurality of refrigerant circuits (10A, 10B). The heat source unit (U) has a first refrigerant circuit (10A) and a second refrigerant circuit (10B). The first refrigerant circuit (10A) and the second refrigerant circuit (10B) have the same basic configuration. Each refrigerant circuit (10A, 10B) is filled with refrigerant. Each refrigerant circuit (10A, 10B) performs a vapor compression refrigeration cycle by circulating the refrigerant.

[0036] The first refrigerant circuit (10A) includes a first compressor (11A), a first air heat exchanger (12A), a first expansion valve (13A), a first water heat exchanger (14A), a first four-way switching valve (15A), and a first accumulator (17A).

[0037] The first compressor (11A) compresses the sucked refrigerant and discharges the compressed refrigerant. The first compressor (11A) is, for example, a scroll compressor, but may be any other type of compressor, such as a screw type, a turbo type, or a rotary type.

[0038] The first air heat exchanger (12A) is an outdoor heat exchanger that exchanges heat between a refrigerant and outdoor air. The heat source unit (U) has a first fan (18A) that transfers air to the first air heat exchanger (12A). The first fan (18A) is a propeller fan. The configurations of the first air heat exchanger (12A) and the second air heat exchanger (12B) will be described in detail later.

[0039] The first expansion valve (13A) is provided on a refrigerant pipe between the first air heat exchanger (12A) and the first water heat exchanger (14A) near the first air heat exchanger (12A). The first expansion valve (13A) is an electronic expansion valve whose opening degree is variable.

[0040] The first water heat exchanger (14A) is a plate-type heat exchanger. The first water heat exchanger (14A) exchanges heat between the refrigerant and water. The first water heat exchanger (14A) is a counterflow heat exchanger. The first water heat exchanger (14A) has a first water flow path (14bA) and a first refrigerant flow path (14aA). The first water flow path (14bA) is connected to the water circuit (30), and the first refrigerant flow path (14aA) is connected to the first refrigerant circuit (10A). The first water heat exchanger (14A) exchanges heat between the water in the first water flow path (14bA) and the refrigerant in the first refrigerant circuit (10A).

[0041] The first four-way selector valve (15A) has a first port (P1), a second port (P2), a third port (P3), and a fourth port (P4). The first port (P1) is connected to the discharge side of the first compressor (11A) via a first discharge pipe (31A). The second port (P2) is connected to the suction side of the first compressor (11A) via a first suction pipe (32A). The third port (P3) is connected to the gas side end of the first air heat exchanger (12A) via a refrigerant piping. The fourth port (P4) is connected to the gas side end of the first refrigerant flow path (14aA) of the first water heat exchanger (14A) via a refrigerant piping.

[0042] The first four-way switching valve (15A) switches between a first state (state shown by solid lines in Figure 1) in which the first port (P1) and the third port (P3) communicate with each other and simultaneously the second port (P2) and the fourth port (P4) communicate with each other, and a second state (state shown by dashed lines in Figure 1) in which the first port (P1) and the fourth port (P4) communicate with each other and simultaneously the second port (P2) and the third port (P3) communicate with each other.

[0043] In the cooling operation of the refrigeration cycle apparatus (1), the first four-way switching valve (15A) is in the first state, and a refrigeration cycle (first refrigeration cycle) is performed in which the first air heat exchanger (12A) functions as a radiator and the first water heat exchanger (14A) functions as an evaporator. In the heating operation of the refrigeration cycle apparatus (1), the first four-way switching valve (15A) is in the second state, and a refrigeration cycle (second refrigeration cycle) is performed in which the first water heat exchanger (14A) functions as a radiator and the first air heat exchanger (12A) functions as an evaporator.

[0044] The first accumulator (17A) is connected to the first suction pipe (32A). The first accumulator (17A) is a sealed container that stores liquid refrigerant contained in the low-pressure refrigerant.

[0045] The second refrigerant circuit (10B) includes a second compressor (11B), a second air heat exchanger (12B), a second expansion valve (13B), a second water heat exchanger (14B), a second four-way switching valve (15B), and a second accumulator (17B). The second water heat exchanger (14B) includes a second refrigerant flow path (14aB) and a second water flow path (14bB). The elements of the second refrigerant circuit (10B) are basically the same as those of the first refrigerant circuit (10A).

[0046] (3) Water circuit As shown in FIG. 1 , the heat source unit (U) has a water circuit (30) through which water flows. The water circuit (30) is configured so that water flows through the first water heat exchanger (14A) and the second water heat exchanger (14B) in this order. Specifically, the water circuit (30) is connected to a pump (33), a first water flow path (14bA) of the first water heat exchanger (14A), and a second water flow path (14bB) of the second water heat exchanger (14B) in this order from upstream to downstream of the water flow. The pump (33) transports water through the water circuit (30). The water flowing through the water circuit (30) exchanges heat with the refrigerant in the first refrigerant flow path (14aA) in the first water flow path (14bA) of the first water heat exchanger (14A), and then exchanges heat with the refrigerant in the second refrigerant flow path (14aB) in the second water flow path (14bB) of the second water heat exchanger (14B).

[0047] (3-1) Configuration of the first water heat exchanger and the second water heat exchanger The first water heat exchanger (14A) and the second water heat exchanger (14B) have the same configuration. Therefore, hereinafter, the first water heat exchanger (14A) and the second water heat exchanger (14B) may be simply referred to as the water heat exchangers (14A, 14B) without being distinguished from each other.

[0048] The water heat exchangers (14A, 14B) will be described using a typical plate-type heat exchanger as an example in FIG. 2. The water heat exchangers (14A, 14B) have a stack (21) in which a plurality of plates (21a, 21b, 21c, 21d, 21e) are stacked in the thickness direction. Each of the plates (21a, 21b, 21c, 21d, 21e) is formed into a generally rectangular shape. In the example of FIG. 2, the stack (21) is formed by stacking a first plate (21a), a second plate (21b), a third plate (21c), a fourth plate (21d), and a fifth plate (21e) in this order.

[0049] The first plate (21a) is formed with a water inlet (23a) which is a water inlet and a water outlet (23b) which is a water outlet. The water inlet (23a) and the water outlet (23b) are aligned vertically on the first plate (21a). The water inlet (23a) is located below the water outlet (23b). A first water pipe (25a) that introduces water into the stack (21) is connected to the water inlet (23a). A second water pipe (25b) that discharges water from the stack (21) is connected to the water outlet (23b). In this way, water flows from the bottom to the top within the stack (21) (solid arrow in FIG. 2).

[0050] The first plate (21a) is formed with a refrigerant inlet (24a) as an inlet for the refrigerant and a refrigerant outlet (24b) as an outlet for the refrigerant. The refrigerant inlet (24a) and the refrigerant outlet (24b) are aligned vertically on the first plate (21a). The refrigerant inlet (24a) is located above the refrigerant outlet (24b). A first refrigerant pipe (26a) that introduces the refrigerant into the stack (21) is connected to the refrigerant inlet (24a). A second refrigerant pipe (26b) that discharges the refrigerant from the stack (21) is connected to the refrigerant outlet (24b). In this manner, the refrigerant flows from the top to the bottom within the stack (21) (as indicated by the dashed arrow in FIG. 2).

[0051] Each plate (21a, 21b, 21c, 21d, 21e) is made of a heat-conductive material. Each plate (21a, 21b, 21c, 21d, 21e) is capable of exchanging heat between both surfaces of the plate (21a, 21b, 21c, 21d, 21e). Gaps are formed between adjacent plates (21a, 21b, 21c, 21d, 21e), and each gap forms a flow path through which water or a refrigerant flows. Specifically, in the example of FIG. 2, refrigerant flow paths (14aA, 14aB) are formed between the first plate (21a) and the second plate (21b) and between the third plate (21c) and the fourth plate (21d). Water flow paths (14bA, 14bB) are formed between the second plate (21b) and the third plate (21c) and between the fourth plate (21d) and the fifth plate (21e). In this manner, the water flow paths (14bA, 14bB) and the refrigerant flow paths (14aA, 14aB) are formed alternately adjacent to each other in the laminate (21). Water flowing through the water flow paths (14bA, 14bB) and the refrigerant flowing through the refrigerant flow paths (14aA, 14aB) exchange heat with each other through the plates (21a, 21b, 21c, 21d, 21e).

[0052] 3, the second water pipe (25b) of the first water heat exchanger (14A) and the first water pipe (25a) of the second water heat exchanger (14B) are common. In this manner, water flowing out of the water outlet (23b) of the first water heat exchanger (14A) flows into the water inlet (23a) of the second water heat exchanger (14B). As a result, the water and the refrigerant flow in opposite directions in the first water heat exchanger (14A) and the second water heat exchanger (14B).

[0053] (4) Sensor 1, the heat source unit (U) has a water temperature sensor (65). The water temperature sensor (65) is provided downstream of the second water heat exchanger (14B) in the water circuit (30). The water temperature sensor (65) detects the temperature of water at the outlet side of the second water flow path (14bB).

[0054] (5) Control unit The heat source unit (U) has a control unit (100). The control unit (100) includes an MCU (Micro Control Unit), an electric circuit, and an electronic circuit. The MCU includes a CPU (Central Processing Unit), a memory, and a communication interface. The memory stores various programs to be executed by the CPU.

[0055] The control unit (100) controls the heat source unit (U). Specifically, the control unit (100) controls ON / OFF switching of the first compressor (11A) and the second compressor (11B), the rotation speeds of the first compressor (11A) and the second compressor (11B), ON / OFF switching of the first fan (18A) and the second fan (18B), the rotation speeds of the first fan (18A) and the second fan (18B), ON / OFF switching of the pump (33), the rotation speed of the pump (33), the opening of the first expansion valve (13A), the opening of the second expansion valve (13B), etc.

[0056] The control unit (100) receives the detection values ​​of the various sensors described above. The control unit (100) detects the rotation speed of each compressor (11A, 11B). The rotation speed of the compressors (11A, 11B) can be detected based on, for example, the value of a current flowing through a motor (not shown) of the compressor (11A, 11B).

[0057] The control unit (100) calculates a predetermined index based on the received detected value and controls each device based on the detected value. The control unit (100) controls the rotation speed of each compressor (11A, 11B) so that the water temperature detected by the water temperature sensor (65) approaches a target temperature.

[0058] (6) Heat source unit structure The structure of the heat source unit (U) of this embodiment will be described with reference to FIGS.

[0059] (6-1) Casing The heat source unit (U) has a hollow casing (40). The casing (40) is formed in a horizontally elongated shape such that the length in the left-right direction is greater than the length in the front-to-rear direction. When viewed from the left-to-right direction, the casing (40) has a shape in which the width in the front-to-rear direction of its upper part is wider.

[0060] The casing (40) has a lower housing portion (41) and an upper housing portion (42). The lower housing portion (41) includes the lower end of the casing (40). The upper housing portion (42) includes the upper end of the casing (40) and is located higher than the lower housing portion (41). A machine chamber (S1) is formed inside the lower housing portion (41). A fan chamber (S2) is formed inside the upper housing portion (42). The lower housing portion (41) has a main body portion (41a) having a rectangular parallelepiped outer shape and an extension portion (41b) extending outward in a first direction (rightward) from the right end of the main body portion (41a). A water pipe (not shown) is disposed in the extension portion (41b) and is connected to the water circuit (30) to transport water between the user-side unit and the water circuit.

[0061] (6-2) Configuration of each equipment in the blower room The blower chamber (S2) is provided with a first air heat exchanger (12A) and a second air heat exchanger (12B). The heat transfer tubes of the first air heat exchanger (12A) and the second air heat exchanger (12B) extend in the left-right direction. The first air heat exchanger (12A) and the second air heat exchanger (12B) are inclined upward so as to approach the outside in the width direction of the casing (40).

[0062] A first fan (18A) and a second fan (18B) are arranged in the upper space of the blower chamber (S2). The first fan (18A) is arranged at the first outlet (O1), and the second fan (18B) is arranged at the second outlet (O2).

[0063] (6-3) Configuration of each equipment in the machine room In the machine room (S1), a first unit (U1) and a second unit (U2) are arranged in this order from right to left, and a water heat exchanger unit (U3) is arranged to the right of the first unit (U1) in the machine room (S1).

[0064] The first unit (U1) includes each element device of the first refrigerant circuit (10A) and a first system electrical component box (6A) for controlling each element device. The element devices of the first refrigerant circuit (10A) include a first compressor (11A) and a first accumulator (17A). Similarly, the second unit (U2) includes a second compressor (11B), a second accumulator (17B), and a second system electrical component box (6B).

[0065] The first compressor (11A) and the second compressor (11B) are arranged side by side in the left-right direction. These compressors (11A, 11B) are arranged near the front of the casing (40). The first accumulator (17A) and the second accumulator (17B) are arranged side by side in the left-right direction. These accumulators are arranged in the middle of the casing (40) in the front-rear direction. Each electrical component box accommodates an inverter device and the like for adjusting the rotation speed of the corresponding compressor (11A, 11B).

[0066] The machine room (S1) is provided with a first water heat exchanger (14A), a second water heat exchanger (14B), and a pump (33). The first water heat exchanger (14A), the second water heat exchanger (14B), and the pump (33) are disposed near the other end (right end) of the machine room (S1) in the left-right direction. The first water heat exchanger (14A) is disposed near the rear side of the casing (40), and the second water heat exchanger (14B) is disposed near the front side of the casing (40). The first water heat exchanger (14A) and the second water heat exchanger (14B) are disposed side by side in the front-rear direction. The pump (33) is disposed to the right of the first water heat exchanger (14A). The first water heat exchanger (14A) and the pump (33) are disposed side by side in the left-right direction. In this manner, the second unit (U2), the first unit (U1), and the water heat exchanger unit (U3) are arranged in this order from left to right in the left-right direction. As a result, the distance between the first air heat exchanger (12A) and the first water heat exchanger (14A) is shorter than the distance between the second air heat exchanger (12B) and the second water heat exchanger (14B). In other words, the length of the refrigerant piping between the first air heat exchanger (12A) and the first water heat exchanger (14A) is shorter than the length of the refrigerant piping between the second air heat exchanger (12B) and the second water heat exchanger (14B).

[0067] (7) Driving behavior The operation of the heat source unit (U) will be described. The heat source unit (U) is configured to perform a cooling operation and a heating operation. In FIG. 1, the flow of refrigerant during the cooling operation is indicated by solid arrows, and the flow of refrigerant during the heating operation is indicated by dashed arrows. In the following description, since the operation of the first refrigerant circuit (10A) and the operation of the second refrigerant circuit (10B) are the same, only the operation of the first refrigerant circuit (10A) will be described, and the operation of the second refrigerant circuit (10B) will be omitted.

[0068] (7-1) Cooling operation In the cooling operation, the control unit (100) operates the first compressor (11A), the first fan (18A), and the pump (33), sets the first four-way switching valve (15A) to the first state, and appropriately adjusts the opening of the first expansion valve (13A).

[0069] The refrigerant compressed by the first compressor (11A) flows through the first air heat exchanger (12A). In the first air heat exchanger (12A), the refrigerant dissipates heat to the outdoor air and is condensed. The condensed high-pressure liquid refrigerant is reduced in pressure to a low pressure when passing through the first expansion valve (13A). The reduced-pressure refrigerant flows through a first refrigerant flow path (14aA) of the first water heat exchanger (14A).

[0070] In the first water heat exchanger (14A), the refrigerant in the first refrigerant flow path (14aA) evaporates and the water in the first water flow path (14bA) is cooled. The water cooled in the first water flow path (14bA) is supplied to the utilization units.

[0071] The refrigerant evaporated in the first water heat exchanger (14A) passes through the first accumulator (17A), and is then sucked into the first compressor (11A) and compressed again. In this way, in the cooling operation, the first water heat exchanger (14A) functions as an evaporator, and the first air heat exchanger (12A) functions as a condenser.

[0072] (7-2) Heating operation In the heating operation, the control unit (100) operates the first compressor (11A), the first fan (18A), and the pump (33), sets the first four-way switching valve (15A) to the second state, and appropriately adjusts the opening of the first expansion valve (13A).

[0073] The refrigerant compressed by the first compressor (11A) flows through the first refrigerant flow path (14aA) of the first water heat exchanger (14A). In the first water heat exchanger (14A), the refrigerant dissipates heat to the water in the first water flow path (14bA) and is condensed, and the water in the first water flow path (14bA) is heated. The heated water is supplied to the utilization units.

[0074] The condensed high-pressure liquid refrigerant is reduced in pressure to a low pressure when passing through the first expansion valve (13A). The reduced-pressure refrigerant flows into the first air heat exchanger (12A). In the first air heat exchanger (12A), the refrigerant absorbs heat from the outdoor air and evaporates.

[0075] The refrigerant evaporated in the first air heat exchanger (12A) passes through the first accumulator (17A), and is then sucked into the first compressor (11A) and compressed again. In this way, in the heating operation, the first water heat exchanger (14A) functions as a condenser, and the first air heat exchanger (12A) functions as an evaporator.

[0076] (8) Configuration of the first air heat exchanger and the second air heat exchanger The heat source unit (U) of this embodiment is configured so that the heat exchange capacity of the first air heat exchanger (12A) is greater than the heat exchange capacity of the second air heat exchanger (12B). The first air heat exchanger (12A) and the second air heat exchanger (12B) will be described below.

[0077] 6 and 7, the first air heat exchanger (12A) and the second air heat exchanger (12B) have a plurality of fins (71) and refrigerant pipes (72). The first air heat exchanger (12A) and the second air heat exchanger (12B) are fin-and-tube heat exchangers in which a plurality of fins (71) are arranged in the thickness direction and a heat transfer pipe (72a) penetrates through the plurality of fins (71). In the following, since the first air heat exchanger (12A) and the second air heat exchanger (12B) have the same basic configuration, the first air heat exchanger (12A) and the second air heat exchanger (12B) may be simply referred to as the air heat exchangers (12A, 12B) without any distinction.

[0078] Each fin (71) is a member formed in the shape of a rectangular plate. Each fin (71) is installed with its long side facing up and down. The multiple fins (71) are erected facing each other and arranged in a row at regular intervals.

[0079] The refrigerant pipes (72) include a plurality of heat transfer pipes (72a), which are circular pipes extending in the left-right direction, and a plurality of U-shaped curved pipes (72b). Refrigerant flows through the refrigerant pipes (72). In the serpentine refrigerant pipes (72), the heat transfer pipes (72a) and the curved pipes (72b) are arranged alternately. The heat transfer pipes (72a) are arranged to penetrate the arranged fins (71). The outer circumferential surfaces of the heat transfer pipes (72a) are in close contact with the fins (71) and are thermally connected to the fins (71). The effective length of the heat transfer pipes (72a) is the length L1 from the fin (71) arranged at one end to the fin (71) arranged at the other end in the arrangement direction. Similarly, in the air heat exchangers (12A, 12B) in which a plurality of fins (71) are arranged in an L-shape and thus are formed in an L-shape when viewed from above, the length of the heat transfer tube (72a) that passes through from the fin (71) located at one end in the arrangement direction of the fins (71) to the fin (71) located at the other end is defined as the effective length of the heat transfer tube (72a).

[0080] In the air heat exchangers (12A, 12B) of this embodiment, the first air heat exchanger (12A) is configured to have a heat exchange capacity 5 to 10% higher than that of the second air heat exchanger (12B). Specifically, as shown in FIG. 8, the first air heat exchanger (12A) has more stages of vertically aligned heat transfer tubes (72a) than the second air heat exchanger (12B). In this embodiment, the number of vertically aligned heat transfer tubes (72a) in the first air heat exchanger (12A) is greater than the number of vertically aligned heat transfer tubes (72a) in the second air heat exchanger (12B). As a result, the first air heat exchanger (12A) promotes heat exchange between the refrigerant and the air more than the second air heat exchanger (12B). Therefore, the first air heat exchanger (12A) has a higher heat dissipation capacity during cooling operation than the second air heat exchanger (12B).

[0081] (9) Heat exchange in air heat exchangers In the air heat exchangers (12A, 12B), refrigerant flows through the refrigerant pipes (72), and air flows between the arranged fins (71). The air heat exchangers (12A, 12B) exchange heat between the refrigerant flowing through the heat transfer pipes (72a) and the air passing between the fins (71).

[0082] In the air heat exchangers (12A, 12B), air flows from the front surface (81) to the rear surface (82) of the air heat exchangers (12A, 12B) (see FIG. 6). The front surface (81) of the air heat exchangers (12A, 12B) is an imaginary plane formed by one long side of each fin (71) and is substantially perpendicular to the short sides of each fin (71). The rear surface (82) of the air heat exchangers (12A, 12B) is an imaginary plane formed by the other long side of each fin (71) and is substantially perpendicular to the short sides of each fin (71). In this way, the air passing through the air heat exchangers (12A, 12B) flows in a direction along the short sides of each fin (71).

[0083] In the air heat exchangers (12A, 12B), the refrigerant flows from one end to the other or from the other end to one end of the refrigerant pipes (72). While flowing through the refrigerant pipes (72), the refrigerant absorbs heat from the air or releases heat to the air.

[0084] (10) Features (10-1) Feature 1 In a water circuit having a plurality of water heat exchangers as in this embodiment, water flowing through the water circuit exchanges heat with a refrigerant in an upstream water heat exchanger and then exchanges heat with a refrigerant in a downstream water heat exchanger. During cooling operation, the water in the water circuit (30) is cooled in the upstream first water heat exchanger (14A) and then further cooled in the downstream second water heat exchanger (14B). Therefore, the water temperature in the first water flow path (14bA) is higher than the water temperature in the second water flow path (14bB). In particular, the control unit (100) controls the first compressor (11A) and the second compressor (11B) so that the rotation speeds of the first compressor (11A) and the second compressor (11B) are equal to each other. Furthermore, when the first water heat exchanger (14A) and the second water heat exchanger (14B) have the same configuration and the first air heat exchanger (12A) and the second air heat exchanger (12B) have the same configuration, the evaporation pressure in the first water heat exchanger (14A) is higher than the evaporation pressure in the second water heat exchanger (14B). In this way, in the refrigeration cycle, the low pressure in the first refrigerant circuit (10A) is higher than the low pressure in the second refrigerant circuit (10B), and accordingly, the high pressure in the first refrigerant circuit (10A) is higher than the high pressure in the second refrigerant circuit (10B). As a result, the input to the first compressor (11A) in the first refrigerant circuit (10A) increases, which may result in a decrease in the COP of the refrigeration cycle apparatus (1).

[0085] Based on this finding, the heat source unit (U) of this embodiment is configured so that the heat exchange capacity of the first air heat exchanger (12A) is greater than that of the second air heat exchanger (12B). As a result, during cooling operation, the heat dissipation capacity of the first air heat exchanger (12A) is greater than that of the second air heat exchanger (12B), thereby suppressing an increase in high pressure in the first refrigerant circuit (10A). This can be explained based on the relationship Q=KAΔt (Q: capacity of the air heat exchangers (12A, 12B), A: heat transfer area of ​​the air heat exchanger, K: heat transfer coefficient, Δt: difference between the condensing temperature and the outside air temperature). Specifically, assuming that the capacity Q is the same when the performance A of the first air heat exchanger (12A) is increased and when the performance A is not increased, Δt decreases accordingly. Since the outdoor air temperature is the same whether the performance A of the first air heat exchanger (12A) is increased or not increased, a decrease in Δt corresponds to a corresponding decrease in the condensation temperature. In this way, the first air heat exchanger (12A) can promote a decrease in the condensation temperature. That is, an increase in the high pressure in the first cold zone circuit (10A) can be suppressed. When an increase in the high pressure in the first refrigerant circuit (10A) is suppressed, a decrease in the COP of the refrigeration cycle apparatus (1) can be suppressed due to a decrease in the input power to the first compressor (11A), for example.

[0086] (10-2) Feature 2 In the heat source unit (U) of this embodiment, the control unit (100) controls the first compressor (11A) and the second compressor (11B) so that the rotation speeds of the first compressor (11A) and the second compressor (11B) are equal. Controlling the compressors (11A, 11B) in this manner can cause a problem that the capacity of the first refrigerant circuit (10A) becomes higher than the capacity of the second refrigerant circuit (10B). However, in the heat source unit (U) of this embodiment, the first air heat exchanger (12A) has a higher heat exchange capacity than the second air heat exchanger (12B), and therefore, this problem can be prevented.

[0087] (10-3) Feature 3 In the heat source unit (U) of this embodiment, the control unit (100) controls the rotation speeds of the first compressor (11A) and the second compressor (11B) in accordance with the water temperature of the water circuit (30) during operation of the refrigeration cycle apparatus (1). In this embodiment, the rotation speeds of the first compressor (11A) and the second compressor (11B) are controlled in the cooling operation so that the water temperature of the water circuit (30) becomes a target water temperature. In this manner, the system is operated while satisfying the required cooling capacity so that the water in the water circuit (30) becomes the target water temperature. Therefore, as long as the required capacity is satisfied, the capacity of the second refrigerant circuit (10B) can be reduced by an amount corresponding to the increase in the capacity of the first refrigerant circuit (10A).

[0088] (10-4) Feature 4 In the heat source unit (U) of this embodiment, the first air heat exchanger (12A) has a greater number of vertically aligned heat transfer tubes (72a) than the second air heat exchanger (12B). As a result, the number of heat transfer tubes (72a) penetrating the fins (71) is greater in the first air heat exchanger (12A) than in the second air heat exchanger (12B), and therefore the heat dissipation capacity of the first air heat exchanger (12A) in the cooling operation can be made greater than the heat dissipation capacity of the second air heat exchanger (12B).

[0089] In addition, the second refrigerant circuit (10B) has a lower evaporation temperature than the first refrigerant circuit (10A), and therefore the high pressure is also suppressed. Therefore, the heat dissipation capacity of the second air heat exchanger (12B) can be reduced. Specifically, even if the first air heat exchanger (12A) is increased in size by increasing the number of heat transfer tubes (72a) of the first air heat exchanger (12A), the second air heat exchanger (12B) can be reduced in size, thereby suppressing an increase in the size of the casing (40) of the heat source unit (U).

[0090] (10-5) Feature 5 The refrigeration cycle apparatus (1) performs a heating operation. In the heating operation, the water in the water circuit (30) is heated in the first water heat exchanger (14A) and then in the second water heat exchanger (14B). Therefore, the water temperature in the second water flow path (14bB) is higher than the water temperature in the first water flow path (14bA). In other words, the condensation temperature in the second water heat exchanger (14B) is higher than the condensation temperature in the first water heat exchanger (14A). As a result, in the refrigeration cycle, the high pressure in the second refrigerant circuit (10B) is higher than the high pressure in the first refrigerant circuit (10A).

[0091] In this embodiment, the heat exchange capacity of the second air heat exchanger (12B) is smaller than that of the first air heat exchanger (12A). In other words, the heat exchange capacity of the first air heat exchanger (12A) is larger than that of the second air heat exchanger (12B). This suppresses an increase in the evaporation temperature of the second refrigerant circuit (10B). In other words, the increase in the evaporation pressure of the second refrigerant circuit (10B) is suppressed, and as a result, an increase in the high pressure of the second refrigerant circuit (10B) is suppressed. Furthermore, the high pressure of the first refrigerant circuit (10A) can be increased by the amount of the suppression of the high pressure increase of the second refrigerant circuit (10B). This makes it possible to perform a heating operation that satisfies the required capacity of the heat source unit (U) and suppresses a decrease in COP.

[0092] (11) Variation 1 In the following modifications, a description will be given of a configuration different from that of the heat source unit (U) of the above embodiment.

[0093] (11-1) Variation 1-1 The air heat exchangers (12A, 12B) of this modified example differ in configuration from the air heat exchangers (12A, 12B) of the above-described embodiment. As shown in FIG. 9 , in this modified example, the first air heat exchanger (12A) has two rows of heat transfer tubes (72a) aligned in the front-to-rear direction, whereas the second air heat exchanger (12B) has one row of heat transfer tubes (72a) aligned in the front-to-rear direction. Thus, the first air heat exchanger (12A) has a greater number of rows of heat transfer tubes (72a) aligned in the front-to-rear direction than the second air heat exchanger (12B). This increases the heat dissipation capacity of the first air heat exchanger (12A) compared to the second air heat exchanger (12B), making it possible to increase the heat exchange capacity of the first air heat exchanger (12A) compared to the second air heat exchanger (12B).

[0094] (11-2) Variation 1-2 The air heat exchangers (12A, 12B) of this modification have a different configuration from the air heat exchangers (12A, 12B) of the above-described embodiment. As shown in Fig. 10, in this modification, the effective length L1 of the heat transfer tubes (72a) of the first air heat exchanger (12A) is longer than the effective length L1 of the heat transfer tubes (72a) of the second air heat exchanger (12B).

[0095] In this way, by making the effective length of the heat transfer tube (72a) in the first air heat exchanger (12A) longer than that of the second air heat exchanger (12B), the width of the first air heat exchanger (12A) can be increased. This increases the area of ​​contact between the air flowing toward the first air heat exchanger (12A) and the first air heat exchanger (12A), thereby making the heat exchange capacity of the first air heat exchanger (12A) higher than that of the second air heat exchanger (12B). This makes it possible to suppress a rise in high pressure in the first refrigerant circuit (10A).

[0096] (11-3) Variation 1-3 The air heat exchangers (12A, 12B) of this modified example have a different configuration from the air heat exchangers (12A, 12B) of the above-described embodiment. As shown in Fig. 11, in this modified example, the fin pitch, which is the distance between adjacent fins of the first air heat exchanger (12A), is narrower than the fin pitch of the second air heat exchanger (12B). For example, when the effective lengths L1 of the heat transfer tubes (72a) of the first air heat exchanger (12A) and the second air heat exchanger (12B) are the same, the number of fins (71) of the first air heat exchanger (12A) is greater than the number of fins (71) of the second air heat exchanger (12B).

[0097] In this way, by narrowing the fin pitch, the number of fins (71) increases. As the number of fins (71) increases, the area of ​​contact between the air and the fins (71) increases, thereby increasing the heat exchange capacity of the air heat exchangers (12A, 12B). Therefore, the heat exchange capacity of the first air heat exchanger (12A) can be made higher than the heat exchange capacity of the second air heat exchanger (12B). This makes it possible to suppress a rise in high pressure in the first refrigerant circuit (10A).

[0098] (12) Variation 2 In the heat source unit (U) of this modified example, the airflow rate of the first fan (18A) is greater than the airflow rate of the second fan (18B). Specifically, the control unit (100) controls the rotation speed of the first fan (18A) to be greater than the rotation speed of the second fan (18B). This promotes heat exchange between the refrigerant and the air in the first air heat exchanger (12A), thereby promoting heat dissipation during cooling operation. This makes it possible to suppress a rise in high pressure in the first refrigerant circuit (10A).

[0099] (13) Variation 3 In the heat source unit (U) of Modification 3, the elements of the first refrigerant circuit (10A) and the elements of the second refrigerant circuit (10B) are basically the same. In the heat source unit (U) of this modification, the configurations of the first water heat exchanger (14A) and the second water heat exchanger (14B) are different. The configurations of the first air heat exchanger (12A) and the second air heat exchanger (12B) are the same.

[0100] The heat source unit (U) of this modified example is configured so that the heat exchange capacity of the first water heat exchanger (14A) is smaller than the heat exchange capacity of the second water heat exchanger (14B). Specifically, the heat exchange capacity of the first water heat exchanger (14A) is 5 to 10% lower than that of the second water heat exchanger (14B).

[0101] When the heat exchange capacity of the water heat exchangers (14A, 14B) is reduced, the evaporation temperature in the water heat exchangers (14A, 14B) decreases compared to before the reduction. This can be explained based on the relationship Q=KAΔt (Q: capacity of the water heat exchangers (14A, 14B), A: heat transfer area of ​​the water heat exchanger, K: heat transfer coefficient, Δt: difference between the evaporation temperature and the water temperature). Specifically, assuming that Q is the same when the performance A of the water heat exchanger is reduced and when the performance A is not reduced, Δt increases accordingly when the performance A of the water heat exchanger is reduced. Because the water temperature of the water heat exchangers (14A, 14B) is the same when the performance A of the water heat exchanger is reduced and when the performance A is not reduced, an increase in Δt reduces the evaporation temperature accordingly. In this way, the first water heat exchanger (14A) can promote a decrease in the evaporation temperature. That is, it is possible to suppress both a rise in low pressure and a rise in high pressure in the first refrigerant circuit (10A).

[0102] The first water heat exchanger (14A) and the second water heat exchanger (14B) are configured as in any one of the following Modifications 3-1 to 3-3.

[0103] (13-1) Variation 3-1 In this modification, the plates (21a, 21b, 21c, 21d, 21e) of the first water heat exchanger (14A) and the second water heat exchanger (14B) have different sizes. Specifically, the size of the plates of the first water heat exchanger (14A) is smaller than the size of the plates (21a, 21b, 21c, 21d, 21e) of the second water heat exchanger (14B). The sizes of the plates (21a, 21b, 21c, 21d, 21e) are the areas of the surfaces of the plates (21a, 21b, 21c, 21d, 21e) facing each other in the arrangement direction of the plates (21a, 21b, 21c, 21d, 21e). The smaller the size of the plates (21a, 21b, 21c, 21d, 21e), the more the flow rate of the refrigerant and water flowing between the plates (21a, 21b, 21c, 21d, 21e) can be reduced, and therefore the heat exchange capacity of the first water heat exchanger (14A) can be made smaller than the heat exchange capacity of the second water heat exchanger (14B).

[0104] (13-2) Variation 3-2 In this modification, the first water heat exchanger (14A) has fewer plates (21a, 21b, 21c, 21d, 21e) than the second water heat exchanger (14B). In other words, the number of plates (21a, 21b, 21c, 21d, 21e) included in the first water heat exchanger (14A) is fewer than the number of plates (21a, 21b, 21c, 21d, 21e) included in the second water heat exchanger (14B). This allows the heat exchange capacity of the first water heat exchanger (14A) to be smaller than the heat exchange capacity of the second water heat exchanger (14B).

[0105] (13-3) Variation 3-3 In this modification, the first water heat exchanger (14A) has fewer water flow paths (14bA, 14bB) through the plates (21a, 21b, 21c, 21d, 21e) or shorter water flow paths than the second water heat exchanger (14B). In other words, the first water flow paths (14bA) of the first water heat exchanger (14A) have fewer water flow paths or shorter water flow paths than the second water flow paths (14bB) of the second water heat exchanger (14B). This allows the heat exchange capacity of the first water heat exchanger (14A) to be smaller than the heat exchange capacity of the second water heat exchanger (14B).

[0106] When the refrigeration cycle apparatus (1) performs a heating operation, the condensation temperature of the second water heat exchanger (14B) is higher than the condensation temperature of the first water heat exchanger (14A), and the high pressure of the second refrigerant circuit (10B) is higher than the high pressure of the first refrigerant circuit (10A). However, even in such a case, the heat exchange capacity of the second water heat exchanger (14B) is greater than the heat exchange capacity of the first water heat exchanger (14A), so the high pressure of the second refrigerant circuit (10B) can be reduced. This makes it possible to reduce the input power to the second compressor (11B), suppress a decrease in COP, and perform a heating operation that satisfies the required capacity.

[0107] (14) Variation 4 The first air heat exchanger (12A) may be a microchannel, and the heat transfer tubes (72a) of the second air heat exchanger (12B) may be copper tubes. Specifically, the first air heat exchanger (12A) shown in Fig. 12 includes a plurality of flat tubes (74), a plurality of fins (71), and a pair of header pipes (73).

[0108] The header pipe (73) includes a first header (73a) and a second header (73b). Each of the first header (73a) and the second header (73b) is formed in the shape of an elongated hollow cylinder with both ends closed.

[0109] A first header (73a) is disposed at the left end of the first air heat exchanger (12A), and a second header (73b) is disposed at the right end. A flat tube (74), which serves as a heat transfer tube, extends from the first header (73a) to the second header (73b). The flat tube (74) has a flat, generally rectangular cross section perpendicular to the direction of extension from one end to the other.

[0110] As shown in Fig. 13, a plurality of refrigerant flow paths (14aA, 14aB) through which a refrigerant flows are formed in the flat tube (74). The plurality of refrigerant flow paths (14aA, 14aB) extend in the extension direction of the flat tube (74). The thickness direction of the flat tube (74) is the up-down direction. The plurality of flat tubes (74) are arranged in the fins (71) so as to face each other in the thickness direction. The plurality of flat tubes (74) are arranged vertically side by side at a constant distance Dp from each other.

[0111] The fins (71) are formed in a generally rectangular plate shape. The fins (71) are formed with a plurality of notches (78) into which the flat tubes (74) are inserted. Each notch (78) opens to one of a pair of long sides of the fins (71) that is located on the front surface (81) side of the first air heat exchanger (12A). The fins (71) are joined by brazing to the flat tubes (74) inserted into the notches (78). In this manner, the fins (71) are attached to the outer surfaces of the flat tubes (74) and are thermally connected to the flat tubes (74).

[0112] The microchannel first air heat exchanger (12A) has a higher heat exchange capacity than the fin-and-tube second air heat exchanger (12B) whose heat transfer tubes (72a) are copper tubes. That is, in the cooling operation, the first air heat exchanger (12A) can have a higher heat dissipation capacity than the second air heat exchanger (12B). This can suppress a rise in high pressure in the first refrigerant circuit (10A). Also in the heating operation, the heat exchange capacity of the second air heat exchanger (12B) is lower than that of the first air heat exchanger (12A). Therefore, the evaporation capacity of the second air heat exchanger (12B) can be lower than that of the first air heat exchanger (12A). This can suppress a rise in high pressure in the second refrigerant circuit (10B), thereby suppressing a decrease in the COP of the heat source unit (U).

[0113] (15) Other embodiments The above embodiment may be configured as follows.

[0114] In the above-described embodiment and each modification, the heat source unit (U) may perform only the cooling operation. Specifically, the first refrigerant circuit (10A) and the second refrigerant circuit (10B) may be configured as refrigerant circuits that perform only the cooling operation.

[0115] In the above-described embodiment and each modification, the heat source unit (U) may perform only the heating operation. Specifically, the first refrigerant circuit (10A) and the second refrigerant circuit (10B) may be configured as refrigerant circuits that perform only the heating operation.

[0116] In the above-described embodiment and each of the modifications except for the third modification, it is sufficient that the first air heat exchanger (12A) has a higher heat exchange capacity than the second air heat exchanger (12B).

[0117] In the third modification, the heat exchange capacity of the first water heat exchanger (14A) may be lower than the heat exchange capacity of the second water heat exchanger (14B).

[0118] In the above-described modified example 1-1, the first air heat exchanger (12A) may be configured so that the fins (71) are arranged in two or more rows in the front-rear direction. For example, the first air heat exchanger (12A) may be configured so that air heat exchangers having the same configuration as the second air heat exchanger (12B) are arranged in two or more rows in the front-rear direction.

[0119] In the above embodiment, the first air heat exchanger (12A) and the second air heat exchanger (12B) are not limited to fin-and-tube heat exchangers.

[0120] In the above embodiment and each of the modified examples, the first water heat exchanger (14A) and the second water heat exchanger (14B) are not limited to plate-type heat exchangers.

[0121] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and detail are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments and modifications may be combined or substituted as appropriate as long as the functionality of the subject matter of this disclosure is not impaired. The terms "first," "second," etc., described above, are used to distinguish the terms to which these terms are attached, and do not limit the number or order of the terms. [Industrial Applicability]

[0122] As described above, the present disclosure is useful for heat source units. [Explanation of symbols]

[0123] 1 Refrigeration cycle device 10A First refrigerant circuit 10B 2nd refrigerant circuit 11A First compressor 11B Second compressor 12A First air heat exchanger 12B Second air heat exchanger 14A 1st water heat exchanger 14B 2nd water heat exchanger 18A No. 1 Fan 18B Second Fan 21a, 21b, 21c, 21d, 21e Plates 30 water circuit 71 Finn 72a Heat transfer tube 100 control section L1 Effective length U Heat source unit

Claims

1. A heat source unit of a refrigeration cycle apparatus (1) that performs a cooling operation to cool water in a water circuit (30), a first refrigerant circuit (10A) having a first compressor (11A), a first air heat exchanger (12A), and a first water heat exchanger (14A) for exchanging heat between a refrigerant and water in the water circuit (30); a second refrigerant circuit (10B) including a second compressor (11B), a second air heat exchanger (12B), and a second water heat exchanger (14B) for exchanging heat between a refrigerant and water in the water circuit (30); In the cooling operation, the first water heat exchanger (14A) and the second water heat exchanger (14B) function as evaporators, and the first air heat exchanger (12A) and the second air heat exchanger (12B) function as condensers; the water circuit (30) is configured so that water flows through the first water heat exchanger (14A) and then the second water heat exchanger (14B); The heat exchange capacity of the first air heat exchanger (12A) is greater than the heat exchange capacity of the second air heat exchanger (12B). Heat source unit.

2. the first air heat exchanger (12A) and the second air heat exchanger (12B) are fin-and-tube heat exchangers in which a plurality of fins (71) are arranged in a thickness direction and a heat transfer tube (72a) penetrates through the plurality of fins (71), The first air heat exchanger (12A) has a higher air temperature than the second air heat exchanger (12B), The number of rows of the heat transfer tubes (72a) arranged in the vertical direction is large, the number of columns of the heat transfer tubes (72a) arranged in the front-rear direction is large, the effective length of the heat transfer tubes (72a) extending in the left-right direction is long, or the fin pitch between adjacent fins (71) is small. The heat source unit according to claim 1 .

3. The first air heat exchanger (12A) has a heat exchange capacity 5 to 10% higher than that of the second air heat exchanger (12B). The heat source unit according to claim 1 or 2.

4. A heat source unit of a refrigeration cycle apparatus (1) that performs a cooling operation to cool water in a water circuit (30), a first refrigerant circuit (10A) having a first compressor (11A), a first air heat exchanger (12A), and a first water heat exchanger (14A) for exchanging heat between a refrigerant and water in the water circuit (30); a second refrigerant circuit (10B) including a second compressor (11B), a second air heat exchanger (12B), and a second water heat exchanger (14B) for exchanging heat between a refrigerant and water in the water circuit (30); In the cooling operation, the first water heat exchanger (14A) and the second water heat exchanger (14B) function as evaporators, and the first air heat exchanger (12A) and the second air heat exchanger (12B) function as condensers; the water circuit (30) is configured so that water flows through the first water heat exchanger (14A) and then the second water heat exchanger (14B); The heat exchange capacity of the first water heat exchanger (14A) is smaller than the heat exchange capacity of the second water heat exchanger (14B). Heat source unit.

5. the first water heat exchanger (14A) and the second water heat exchanger (14B) are plate-type heat exchangers in which a plurality of plates (21a, 21b, 21c, 21d, 21e) are arranged in a thickness direction; The first water heat exchanger (14A) has smaller plates (21a, 21b, 21c, 21d, 21e) than the second water heat exchanger (14B), has fewer plates (21a, 21b, 21c, 21d, 21e), or has fewer or shorter water flow paths in the plates (21a, 21b, 21c, 21d, 21e). The heat source unit according to claim 4.

6. The first water heat exchanger (14A) has a heat exchange capacity 5 to 10% lower than that of the second water heat exchanger (14B). The heat source unit according to claim 4 or 5.

7. a control unit (100) that controls the first compressor (11A) and the second compressor (11B), The control unit (100) controls the first compressor (11A) and the second compressor (11B) so that the rotation speeds of the first compressor (11A) and the second compressor (11B) are equal to each other. The heat source unit according to claim 1 or 2.

8. The control unit (100) controls the rotation speeds of the first compressor (11A) and the second compressor (11B) in accordance with the water temperature of the water circuit (30) during operation of the refrigeration cycle apparatus (1). The heat source unit according to claim 7.

9. a first fan (18A) that delivers air to the first air heat exchanger (12A); a second fan (18B) that transports air to the second air heat exchanger (12B); The air volume of the first fan (18A) is greater than the air volume of the second fan (18B). The heat source unit according to claim 1 or 2.

10. the first air heat exchanger (12A) is a microchannel heat exchanger, The second air heat exchanger (12B) is a fin-and-tube heat exchanger in which a plurality of fins (71) are arranged in a thickness direction and a heat transfer tube (72a) penetrates through the plurality of fins (71), The heat transfer tube (72a) of the second air heat exchanger (12B) is a copper tube. The heat source unit according to claim 1 .

11. The distance between the first air heat exchanger (12A) and the first water heat exchanger (14A) is shorter than the distance between the second air heat exchanger (12B) and the second water heat exchanger (14B). The heat source unit according to claim 1 or 2.

12. The refrigeration cycle apparatus (1) performs a heating operation to heat water in the water circuit (30), The heat exchange capacity of the second air heat exchanger (12B) is smaller than the heat exchange capacity of the first air heat exchanger (12A). The heat source unit according to claim 1 .

13. The refrigeration cycle apparatus (1) performs a heating operation to heat water in the water circuit (30), The heat exchange capacity of the second water heat exchanger (14B) is greater than the heat exchange capacity of the first water heat exchanger (14A). The heat source unit according to claim 1 .

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