Refrigeration cycle device and heat source module

Abstract

To suppress reduction of comfort while securing reliability of a compressor whichever of a direct expansion unit or an indirect expansion unit is connected as a use side unit.SOLUTION: A refrigeration cycle device comprises a use side unit and a heat source module. The use side unit includes a refrigerator heat exchanger which performs a heat exchange between a refrigerator and a heat exchange object. The heat source module includes a compressor and a control device which controls a rotation speed of the compressor in such a manner that a temperature of the refrigerator flowing into the refrigerator heat exchanger is a target value. The control device includes a target temperature setting section which sets an upper limit of the target value when performing a cooling operation to cool the heat exchange object. The target temperature setting section sets the upper limit of the target value in a first upper limit temperature setting mode when the use side unit to be operated is a direct expansion unit and sets the upper limit of the target value in a second upper limit temperature setting mode that is different from the first upper limit temperature setting mode when the use side unit to be operated is an indirect expansion unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a refrigeration cycle apparatus and a heat source module that include a direct expansion unit or a partial expansion unit as a utilization side unit. [Background technology]

[0002] In a refrigeration cycle device, when a liquid-phase refrigerant flows into a compressor, so-called liquid compression occurs, which leads to a decrease in the reliability of the compressor. In order to prevent the liquid-phase refrigerant from flowing into the compressor, a technique is known in which a target value of the evaporation temperature is set so that the degree of superheat of the refrigerant drawn into the compressor is a predetermined value, and the refrigerant circuit is controlled so that the evaporation temperature reaches the target value (see, for example, Patent Document 1).

[0003] On the other hand, in a refrigeration cycle equipped with a direct expansion unit or a partial expansion unit as a user unit, for example, during cooling operation, the target value of the evaporation temperature can be set according to the load of the user unit, thereby achieving the required capacity. In other words, in order for the room temperature of the air-conditioned space to reach the set temperature, the evaporation temperature must be lower than the target temperature. On the other hand, to ensure the reliability of the compressor, the evaporation temperature must be lower than the temperature of the heat medium with which the refrigerant is heat-exchanged. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2016-205732 Summary of the Invention [Problem to be solved by the invention]

[0005] However, because the technology described in Patent Document 1 is based on the premise that the user unit is a direct expansion unit, if a direct expansion unit with a different heat medium (air and water) or control target (room temperature and water temperature) is connected as the user unit, it may not be possible to lower the evaporation temperature of the refrigerant below the temperature of the heat medium with which the heat is exchanged. This may result in a decrease in comfort due to an inability to achieve the required capacity, or a decrease in compressor reliability due to the inflow of liquid refrigerant.

[0006] In view of the above circumstances, an object of the present invention is to provide a refrigeration cycle device and a heat source module that can ensure the reliability of the compressor while suppressing a decrease in comfort, regardless of whether a direct expansion unit or a intermediate expansion unit is connected as the user unit. [Means for solving the problem]

[0007] A refrigeration cycle apparatus according to one aspect of the present invention includes a utilization side unit and a heat source module. The user side unit has a refrigerant heat exchanger that exchanges heat between a refrigerant and a heat exchange target. The heat source module has a compressor and a control device that controls the rotation speed of the compressor so that the temperature of the refrigerant flowing into the refrigerant heat exchanger reaches a target value. The control device has a target temperature setting unit that sets an upper limit of the target value when performing a cooling operation to cool the heat exchange target. The target temperature setting unit sets the upper limit of the target value in a first upper limit temperature setting mode when the user side unit to be operated is a direct expansion unit, and sets the upper limit of the target value in a second upper limit temperature setting mode different from the first upper limit temperature setting mode when the user side unit to be operated is an intermediate expansion unit.

[0008] According to the above-mentioned refrigeration cycle device, since it has the above-mentioned target temperature setting unit, regardless of whether a direct expansion unit or an intermediate expansion unit is connected as the user side unit, it is possible to ensure the reliability of the compressor while suppressing a decrease in comfort.

[0009] The utilization side unit may be a direct expansion unit including a heat exchange target sensor that detects the temperature of the heat exchange target and a temperature setting unit that allows a set temperature to be input. In this case, the target temperature setting unit may calculate the target value based on a difference between the detected temperature of the heat exchange target sensor and the set temperature in the first upper limit temperature setting mode, and set an upper limit of the target value according to the set temperature.

[0010] Alternatively, the utilization side unit may be an intermediate expansion unit including a heat medium circuit for circulating a heat medium between a relay unit having a heat medium heat exchanger as the refrigerant heat exchanger and an indoor unit having an indoor heat exchanger, a return temperature sensor for detecting the temperature of the heat medium flowing into the heat medium heat exchanger, a room temperature sensor for detecting the temperature of indoor air flowing into the indoor heat exchanger, and a temperature setting unit into which a set temperature can be input. In this case, the target temperature setting unit may set the target value based on the difference between the temperature detected by the room temperature sensor and the set temperature, and set an upper limit of the target value according to the temperature detected by the return temperature sensor, in the second upper limit temperature setting mode.

[0011] Alternatively, the utilization side unit may be an intermediate expansion unit including a heat medium circuit for circulating a heat medium between an intermediate unit having a heat medium heat exchanger as the refrigerant heat exchanger and an indoor unit having an indoor heat exchanger, a supply temperature sensor for detecting the temperature of the heat medium flowing out of the heat medium heat exchanger, and a return temperature sensor for detecting the temperature of the heat medium flowing into the heat medium heat exchanger. In this case, the target temperature setting unit may set the target value based on a difference between the temperatures detected by the supply temperature sensor and the return temperature sensor, and set an upper limit of the target value according to the temperature detected by the supply temperature sensor, in the second upper limit temperature setting mode.

[0012] The heat source module may be connected to a plurality of user-side units including both the direct expansion unit and the intermediate expansion unit. In this case, the target temperature setting unit may set the upper limit of the target value to the lower of the upper limit of the target value set in the first upper limit temperature setting mode and the upper limit of the target value set in the second upper limit temperature setting mode.

[0013] A refrigeration cycle apparatus according to another aspect of the present invention includes a utilization side unit and a heat source module. The user side unit has a refrigerant heat exchanger that exchanges heat between a refrigerant and a heat exchange target. The heat source module has a compressor and a control device that controls the rotation speed of the compressor so that the temperature of the refrigerant flowing into the refrigerant heat exchanger reaches a target value. The control device has a target temperature setting unit that sets a lower limit of the target value when performing a heating operation to heat the heat exchange target. The target temperature setting unit sets the lower limit of the target value in a first lower limit temperature setting mode when the user side unit to be operated is a direct expansion unit, and sets the lower limit of the target value in a second lower limit temperature setting mode different from the first lower limit temperature setting mode when the user side unit to be operated is an intermediate expansion unit.

[0014] The utilization side unit may be a direct expansion unit including a heat exchange target sensor that detects the temperature of the heat exchange target and a temperature setting unit that can input a set temperature. In this case, the target temperature setting unit may calculate the target value based on a difference between the detected temperature of the heat exchange target sensor and the set temperature in the first lower limit temperature setting mode, and set a lower limit of the target value according to the set temperature.

[0015] Alternatively, the utilization side unit may be an intermediate expansion unit including a heat medium circuit that circulates a heat medium between a relay unit having a heat medium heat exchanger as the refrigerant heat exchanger and an indoor unit having an indoor heat exchanger, a return temperature sensor that detects the temperature of the heat medium flowing into the heat medium heat exchanger, a room temperature sensor that detects the temperature of indoor air flowing into the indoor heat exchanger, and a temperature setting unit that can input a set temperature. In this case, the target temperature setting unit may set the target value based on a difference between the temperature detected by the room temperature sensor and the set temperature, and set a lower limit of the target value according to the temperature detected by the return temperature sensor in the second lower limit temperature setting mode.

[0016] Alternatively, the utilization side unit may be an intermediate expansion unit including a heat medium circuit for circulating a heat medium between an intermediate unit having a heat medium heat exchanger as the refrigerant heat exchanger and an indoor unit having an indoor heat exchanger, a supply temperature sensor for detecting the temperature of the heat medium flowing out of the heat medium heat exchanger, and a return temperature sensor for detecting the temperature of the heat medium flowing into the heat medium heat exchanger. In this case, the target temperature setting unit may set the target value based on a difference between the temperatures detected by the supply temperature sensor and the return temperature sensor, and set a lower limit of the target value in accordance with the temperature detected by the supply temperature sensor, in the second lower limit temperature setting mode.

[0017] The heat source module may be connected to a plurality of user-side units including both the direct expansion unit and the intermediate expansion unit. In this case, the target temperature setting unit may set, as the lower limit of the target value, the higher of the lower limit of the target value set in the first lower limit temperature setting mode and the lower limit of the target value set in the second lower limit temperature setting mode.

[0018] A refrigeration cycle apparatus according to yet another embodiment of the present invention includes a utilization side unit and a heat source module. The user side unit has a refrigerant heat exchanger that exchanges heat between a refrigerant and a heat exchange target. The heat source module has a compressor and a control device that controls the rotation speed of the compressor so that the temperature of the refrigerant flowing into the refrigerant heat exchanger reaches a target value. The control device has a target temperature setting unit that sets an upper limit of the target value when performing cooling operation to cool the heat exchange target and a lower limit of the target value when performing heating operation to heat the heat exchange target. The target temperature setting unit During cooling operation, when the user-side unit that operates is a direct expansion unit, the upper limit of the target value is set in a first upper limit temperature setting mode, and when the user-side unit that operates is a direct expansion unit, the upper limit of the target value is set in a second upper limit temperature setting mode that is different from the first upper limit temperature setting mode, During heating operation, when the user side unit that operates is a direct expansion unit, the lower limit of the target value is set in a first lower limit temperature setting mode, and when the user side unit that operates is a partial expansion unit, the lower limit of the target value is set in a second lower limit temperature setting mode that is different from the first lower limit temperature setting mode.

[0019] The heat source module may be connected to a plurality of user-side units including both the direct expansion unit and the intermediate expansion unit. In this case, the target temperature setting unit may set the upper limit of the target value to the lower of the upper limit of the target value set in the first upper limit temperature setting mode and the upper limit of the target value set in the second upper limit temperature setting mode.

[0020] A heat source module according to one embodiment of the present invention is connected to a user unit having a refrigerant heat exchanger that exchanges heat between a refrigerant and a heat exchange target, and includes a compressor and a control device that controls the rotation speed of the compressor so that the temperature of the refrigerant flowing into the refrigerant heat exchanger reaches a target value. The control device has a target temperature setting unit that sets an upper limit of the target value when performing cooling operation to cool the heat exchange target and a lower limit of the target value when performing heating operation to heat the heat exchange target. The target temperature setting unit During cooling operation, when the user-side unit that operates is a direct expansion unit, the upper limit of the target value is set in a first upper limit temperature setting mode, and when the user-side unit that operates is a direct expansion unit, the upper limit of the target value is set in a second upper limit temperature setting mode that is different from the first upper limit temperature setting mode, During heating operation, when the user side unit that operates is a direct expansion unit, the lower limit of the target value is set in a first lower limit temperature setting mode, and when the user side unit that operates is a partial expansion unit, the lower limit of the target value is set in a second lower limit temperature setting mode that is different from the first lower limit temperature setting mode.

[0021] The user-side unit may include both the direct expansion unit and the intermediate expansion unit. In this case, the target temperature setting unit may set the upper limit of the target value to the lower of the upper limit of the target value set in the first upper limit temperature setting mode and the upper limit of the target value set in the second upper limit temperature setting mode. [Effects of the Invention]

[0022] According to the present invention, regardless of whether a direct expansion unit or a partial expansion unit is connected as the user side unit, it is possible to suppress a decrease in comfort while ensuring the reliability of the compressor. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a refrigerant-water circuit diagram of a refrigeration cycle device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram showing a configuration of a control device in the refrigeration cycle device. [Figure 3] FIG. 2 is a functional block diagram of the control device. [Figure 4] 4 is a flowchart showing an example of a procedure for determining an upper limit of a target value of evaporation temperature, which is executed in the control device. [Figure 5] 5 is a flowchart illustrating an example of a procedure for determining a lower limit of a target value of a condensing temperature, which is executed in the control device. [Figure 6]4 is a flowchart showing an example of a procedure for determining a control mode for the rotation speed of a compressor, which is executed in the control device. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0025] [Configuration of refrigeration cycle equipment] 1 is a refrigerant-water circuit diagram of a refrigeration cycle apparatus 100 according to one embodiment of the present invention. The refrigeration cycle apparatus 100 of this embodiment is an air conditioner, and includes an outdoor unit 2, a first indoor unit 3, a relay unit 50, and a control device 90.

[0026] The outdoor unit 2 corresponds to the heat source module in the present invention, and the first indoor unit 3 and the relay unit 50 correspond to the user side units in the present invention. Furthermore, the first indoor unit 3 corresponds to the direct expansion unit in the present invention, and the relay unit 50 and the second indoor unit 4, which is an indoor unit connected thereto, correspond to the intermediate expansion unit in the present invention. Note that direct expansion refers to a method of expanding a refrigerant near the air to be conditioned to perform heat exchange, and intermediate expansion refers to a method of using that refrigerant to transport cooled or heated water to perform heating or cooling.

[0027] (Outdoor unit) The outdoor unit 2 has a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an outdoor expansion valve 24, and an accumulator 25. By connecting these devices to the first indoor unit 3 and the relay unit 50 via piping, a primary refrigerant circuit 20 is formed in which refrigerant (primary refrigerant) circulates in the refrigerant-water circuit of the refrigeration cycle apparatus 100. In addition, the first indoor unit 3 and the relay unit 50 are connected in parallel.

[0028] Compressor 21 is a variable displacement compressor whose operating capacity can be changed by controlling its rotation speed with an inverter (not shown). The refrigerant discharge side of compressor 21 is connected to port a of four-way valve 22 via a discharge pipe 61. The refrigerant suction side of compressor 21 is connected to the refrigerant outflow side of accumulator 25 via a suction pipe 65.

[0029] The four-way valve 22 is a valve for switching the direction of refrigerant flow, and has four ports a, b, c, and d. As described above, port a is connected to the refrigerant discharge side of the compressor 21 by a discharge pipe 61. Port b is connected to one refrigerant inlet / outlet of the outdoor heat exchanger 23 by a refrigerant piping 62. Port c is connected to the refrigerant inlet / outlet of the accumulator 25 by a refrigerant piping 66. Port d is connected to the gas refrigerant inlet / outlet 51b of the water-refrigerant heat exchanger 51 in the relay unit 50 and one refrigerant inlet / outlet of the indoor heat exchanger 31 in the indoor unit 3 by an outdoor unit gas pipe 64, a gas branch pipe 17, and a gas pipe 37.

[0030] The outdoor heat exchanger 23 exchanges heat between the refrigerant and the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 29. One refrigerant inlet and outlet of the outdoor heat exchanger 23 is connected to port b of the four-way valve 22 by refrigerant piping 62 as described above, and the other refrigerant inlet and outlet is connected to the liquid refrigerant inlet and outlet 51a of the water-refrigerant heat exchanger 51 in the relay unit 50, and to the first expansion valve 33 in the first indoor unit 3, the outdoor unit liquid pipe 63, the liquid branch pipe 16, and the liquid pipe 36.

[0031] The outdoor expansion valve 24 is, for example, an electronic expansion valve. The outdoor expansion valve 24 is arranged in the outdoor unit liquid pipe 63, and its opening degree can be adjusted to reduce the pressure of the refrigerant passing through it.

[0032] The outdoor fan 29 is made of resin and is arranged near the outdoor heat exchanger 23. The outdoor fan 29 is rotated by a fan motor (not shown) to take in outside air from an intake port (not shown) of the outdoor unit 2 into the interior of the outdoor unit 2, and discharges the outside air that has exchanged heat with the refrigerant in the outdoor heat exchanger 23 to the outside of the outdoor unit 2 from an outlet port (not shown) of the outdoor unit 2.

[0033] (1st indoor unit) The first indoor unit 3 has an indoor heat exchanger 31, an indoor fan 32, and a first expansion valve (indoor expansion valve) 33. Although the number of first indoor units 3 is one in Fig. 1, this is not limited to this, and two or more first indoor units 3 may be connected in parallel to the outdoor unit 2.

[0034] The indoor heat exchanger 31 is a refrigerant heat exchanger that exchanges heat between the refrigerant and the outside air drawn into the first indoor unit 3 by the rotation of the indoor fan 32. The outdoor unit gas pipe 64 and the first indoor unit 3 are connected by a gas pipe 37, and the gas pipe 37 and one refrigerant inlet and outlet of the indoor heat exchanger 31 are connected by an indoor unit gas pipe 39. The outdoor unit liquid pipe 63 and the first indoor unit 3 are connected by a liquid pipe 36, and the liquid pipe 36 and one refrigerant inlet and outlet of the indoor heat exchanger 31 are connected by an indoor unit liquid pipe 38.

[0035] The first expansion valve 33 is, for example, an electronic expansion valve. The first expansion valve 33 is arranged in the indoor unit liquid pipe 38, and its opening degree can be adjusted to reduce the pressure of the refrigerant passing through it.

[0036] The indoor fan 32 is made of resin and is located near the indoor heat exchanger 31. The indoor fan 32 is driven by a fan motor (not shown), takes in indoor air from an intake port (not shown) of the first indoor unit 3, and releases the air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 into the room from an outlet port (not shown) of the first indoor unit 3.

[0037] The first indoor unit 3 further includes a temperature setting section 35 into which an indoor temperature (set temperature) can be input.

[0038] (relay unit) The relay unit 50 is connected to the outdoor unit 2 in parallel with the first indoor unit 3. The relay unit 50 has a water-refrigerant heat exchanger 51 and a second expansion valve 52.

[0039] 1 shows one relay unit 50, but this is not limiting and two or more relay units 50 may be connected in parallel. Furthermore, the relay unit 50 is installed outdoors as a separate unit from the outdoor unit 2, but may also be installed inside the outdoor unit 2.

[0040] The water-refrigerant heat exchanger 51 corresponds to the heat medium heat exchanger of the present invention. The water-refrigerant heat exchanger 51 is a refrigerant heat exchanger that exchanges heat between a refrigerant and a heat exchange target, which in this embodiment is water. However, the heat exchange target is not limited to this, and may also be antifreeze liquid. The water-refrigerant heat exchanger 51 is, for example, a double-pipe heat exchanger, and has a refrigerant-side flow path 511, a water-side flow path 512, a liquid refrigerant inlet / outlet 51a, a gas refrigerant inlet / outlet 51b, a water inlet 51c, and a water outlet 51d.

[0041] One end of the refrigerant-side flow path 511 is connected to the liquid refrigerant inlet / outlet 51a and the other end is connected to the gas refrigerant inlet / outlet 51b. The water-side flow path 512 is connected to the water inlet 51c and the other end is connected to the water outlet 51d. In the water-refrigerant heat exchanger 51, heat is exchanged between the refrigerant flowing through the refrigerant-side flow path 511 and the water flowing through the water-side flow path 512.

[0042] The liquid refrigerant inlet / outlet 51a is connected to the other refrigerant inlet / outlet of the outdoor heat exchanger 23 by a liquid branch pipe 16 and an outdoor unit liquid pipe 63. The liquid branch pipe 16 is a refrigerant pipe branching from the liquid pipe 36. The gas refrigerant inlet / outlet 51b is connected to port d of the four-way valve 22 by a gas branch pipe 17 and an outdoor unit gas pipe 64. The gas branch pipe 17 is a refrigerant pipe branching from the gas pipe 37. The water inlet 51c is connected to the indoor heat exchanger 41 of the second indoor unit 4 by a second water pipe 12. The water outlet 51d is connected to the indoor heat exchanger 41 of the second indoor unit 4 by a first water pipe 11.

[0043] The second expansion valve 52 is, for example, an electronic expansion valve. The second expansion valve 52 is disposed between the outdoor expansion valve 24 and the liquid refrigerant inlet / outlet 51a, and its opening degree can be adjusted to reduce the pressure of the refrigerant passing through it.

[0044] (Secondary refrigerant circuit) The water-refrigerant heat exchanger 51 is connected to a water circuit 40, which is a secondary refrigerant circuit through which water, which is a secondary refrigerant, circulates. The water circuit 40 corresponds to the heat medium circuit in the present invention, and includes the second indoor unit 4 connected to the water-refrigerant heat exchanger 51 of the relay unit 50, and a circulation pump 44. Note that although the number of water circuits 40 in FIG. 1 is one, this is not limiting, and two or more water circuits 40 may be connected in parallel to the relay unit 50.

[0045] The second indoor unit 4 has an indoor heat exchanger 41, an indoor fan 42, and an on-off valve 43.

[0046] The indoor heat exchanger 41 is a water-air heat exchanger that exchanges heat between water and the outside air that is drawn into the second indoor unit 4 by the rotation of the indoor fan 42. The inlet side of the indoor heat exchanger 41 is connected to the water outlet 51d of the water-refrigerant heat exchanger 51 by a first water pipe (forward pipe) 11. The outlet side of the indoor heat exchanger 41 is connected to the water inlet 51c of the water-refrigerant heat exchanger 51 by a second water pipe (return pipe) 12.

[0047] The indoor fan 42 is made of resin and is arranged near the indoor heat exchanger 41. The indoor fan 42 is rotated by a fan motor (not shown) to take in indoor air into the second indoor unit 4 from an intake port (not shown) of the second indoor unit 4, and blows the air that has exchanged heat with water in the indoor heat exchanger 41 out into the room from an outlet (not shown) of the second indoor unit 4. The indoor fan 42 and the indoor heat exchanger 41 form a fan coil unit (FCU).

[0048] The on-off valve 43 is disposed in the first water pipe 11 and is a shutoff valve capable of shutting off the flow of water from the water outlet 51d of the water-refrigerant heat exchanger 51 toward the indoor heat exchanger 41. The opening and closing of the on-off valve 43 is controlled individually for each of the second indoor units 4a, 4b, and the on-off valve 43 of the second indoor unit 4 that is not operating (or is to be stopped) is switched to the closed state.

[0049] The on-off valve 43 may be a flow control valve whose opening can be adjusted as desired. In this case, the flow rate of water flowing through the indoor heat exchanger 41 can be controlled according to the opening rate of the flow control valve. This makes it possible to adjust the flow rate of water flowing into the indoor heat exchanger 41 in cases where, for example, the capacity required by the second indoor unit 4 exceeds the capacity required even when the circulation pump 44 is operating at the minimum rotation speed, thereby improving the ability to follow the required capacity and increasing comfort.

[0050] The second indoor unit 4 further includes a temperature setting unit 45 that can input the indoor temperature (set temperature). When the relay unit 50 includes a receiving unit 53, which will be described later, the second indoor unit 4 does not need to include the temperature setting unit 45.

[0051] The circulation pump 44 is a variable capacity pump driven by a motor (not shown). When the circulation pump 44 is driven, water flows out from the water outlet 51d of the water-refrigerant heat exchanger 51 into the first water pipe 11, and circulates so that water flows into the water inlet 51c of the water-refrigerant heat exchanger 51 via the indoor heat exchanger 41 and the second water pipe 12.

[0052] The flow rate of water circulated by driving the circulation pump 44 is controlled by the rotation speed of the motor. This allows water to be supplied at the same flow rate to each second indoor unit 4. In the example shown in Figure 1, the circulation pump 44 is arranged in the second water piping 12, but instead, it may be arranged in the first water piping 11, or may be arranged inside the relay unit 50.

[0053] The relay unit 50 may further include a receiving unit 53 that receives an input instruction from a user. The receiving unit 53 may be an input operation unit that accepts an input instruction from a user, or may be a receiving device that receives an input signal corresponding to the input instruction generated by the input operation unit. The input instruction includes, for example, an instruction value related to the set temperature of each indoor space in which the indoor unit 3 is installed, or the temperature of the water circulating through the water circuit 40 (the temperature of the water flowing out of the water-refrigerant heat exchanger 51). When the receiving unit 53 receives the input instruction, the relay unit 50 transmits a notification to that effect to the control device 90.

[0054] (sensors) Various sensors are provided in the refrigeration cycle apparatus 100. In the outdoor unit 2, a high-pressure sensor 71 that detects the pressure of the refrigerant discharged from the compressor 21 and a discharge temperature sensor 72 that detects the temperature of the refrigerant discharged from the compressor 21 are provided in the discharge pipe 61. A low-pressure sensor 73 that detects the pressure of the refrigerant sucked into the compressor 21 and an suction temperature sensor 74 that detects the temperature of the refrigerant sucked into the compressor 21 are provided in the suction pipe 65.

[0055] The outdoor heat exchanger 23 is provided with a heat exchange temperature sensor 75 for detecting the temperature of the refrigerant flowing through the outdoor heat exchanger 23. An outdoor air temperature sensor 76 is provided near an air inlet (not shown) of the outdoor unit 2 for detecting the temperature of the outdoor air flowing into the outdoor unit 2, i.e., the outdoor air temperature.

[0056] The first indoor unit 3 is provided with a room temperature sensor 83 that detects the temperature (room temperature) of the air flowing into the first indoor unit 3. This room temperature sensor 83 corresponds to the heat exchange target sensor in the present invention. In addition, a third refrigerant temperature sensor 82 that detects the temperature of the refrigerant flowing into the indoor heat exchanger 31 during cooling operation is provided in the indoor unit liquid pipe 38 between the first expansion valve 33 and the indoor heat exchanger 31.

[0057] The second indoor unit 4 is provided with a room temperature sensor 84 that detects the temperature (room temperature) of the air flowing into the indoor heat exchanger 41 of the second indoor unit 4. The first water pipe 11 is provided with a supply temperature sensor 80 that detects the temperature of the water flowing out of the water-refrigerant heat exchanger 51. The second water pipe 12 is provided with a return temperature sensor 81 that detects the temperature of the water flowing into the water-refrigerant heat exchanger 51. If the second indoor unit 4 is not provided with a temperature setting unit 45, the second indoor unit 4 does not need to be provided with the room temperature sensor 84.

[0058] A first refrigerant temperature sensor 78 is provided in the liquid branch pipe 16 of the relay unit 50 between the second expansion valve 52 and the liquid refrigerant inlet / outlet 51a to detect the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51 during cooling operation, and a second refrigerant temperature sensor 79 is provided in the gas branch pipe 17 to detect the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51 during heating operation.

[0059] (Control device) The control device 90 is, for example, an outdoor unit control device provided in the outdoor unit 2, and is mounted on a control board housed in an electrical component box (not shown) of the outdoor unit 2.

[0060] 2 is a block diagram showing the configuration of the control device 90. As shown in the figure, the control device 90 has a CPU 91, a storage unit 92, a communication unit 93, a sensor input unit 94, and a rotation speed detection unit 95.

[0061] The memory unit 92 is a non-volatile memory such as a flash memory, and stores the control program and control parameters of the outdoor unit 2, detection values ​​corresponding to detection signals from various sensors, the control states of the compressor 21 and outdoor fan 29, etc., the rotation speeds of the indoor fans 32, 42 obtained via the communication unit 93, the control states of the first indoor unit 3 and the second indoor unit 4, including the operation mode set and input by the user, etc.

[0062] The communication unit 93 is an interface for communicating with the first indoor unit 3, the second indoor unit 4, and the relay unit 50. The sensor input unit 94 takes in detection results from various sensors in the outdoor unit 2 and outputs them to the CPU 91. The rotation speed detection unit 95 detects the rotation speed of the motor of the compressor 21 and outputs it to the CPU 91. The rotation speed detection unit 95 may be configured to directly detect the rotation speed of the motor using an encoder or the like attached to the drive shaft of the motor, or may be configured to detect the rotation speed of the motor from the drive current supplied to the motor. In the following description, the rotation speed of the compressor 21 refers to the rotation speed of the motor.

[0063] The CPU 91 is a control unit that controls the operation of each part of the outdoor unit 2, including the compressor 21, by executing a program stored in the storage unit 92. The program is installed in the control device 90 via, for example, various storage media. Alternatively, the program may be installed via the Internet or the like.

[0064] The CPU 91 takes in the detection results of each sensor of the outdoor unit 2 described above via the sensor input unit 94. Furthermore, the CPU 91 takes in control signals transmitted from the first indoor unit 3 and the second indoor unit 4 via the communication unit 93. The control signals transmitted from the first indoor unit 3 and the second indoor unit 4 include the required operating capacity (indoor load) requested by the first indoor unit 3 and the second indoor unit 4, etc.

[0065] Based on the captured detection results and control signals, the CPU 91 controls the drive of the compressor 21, the outdoor fan 29, the indoor fans 32 and 42, and the circulation pump 44, for example, by setting the indicated rotation speeds at which these are driven, and generates control commands for these. The CPU 91 also controls the switching of the four-way valve 22 based on the captured detection results and control signals. Furthermore, the CPU 91 controls the opening degrees of the outdoor expansion valve 24, the first expansion valve 33, and the second expansion valve 52, and controls the opening and closing of the on-off valve 43, based on the captured detection results and control signals.

[0066] The CPU 91 is configured to execute either a room temperature control mode in which the rotation speed of the compressor 21 is controlled based on information about the indoor load, or a water temperature control mode in which the rotation speed of the compressor 21 is controlled based on information about the thermal load of the water circuit 40. Details of the room temperature control mode and the water temperature control mode will be described later. Here, "indoor load" refers to a load calculated based on the detection results of various sensors installed in the first indoor unit 3 and the second indoor unit 4. Also, "thermal load" refers to a load calculated based on the detection results of various sensors in the water circuit 40.

[0067] [Basic operation of refrigeration cycle equipment] Next, a description will be given of the basic operation of the refrigeration cycle apparatus 100. Hereinafter, the operation of the refrigeration cycle apparatus 100 during cooling operation and heating operation will be described.

[0068] (Cooling operation) When the refrigeration cycle apparatus 100 performs cooling operation (cooling operation mode), the four-way valve 22 is switched to the state shown by the solid lines in Fig. 1, i.e., the state where port a and port b are connected and port c and port d are connected, and the compressor 21 and the circulation pump 44 are driven in this state. Driving the compressor 21 causes refrigerant to circulate through the refrigerant circuit 20, and driving the circulation pump 44 causes water to circulate through the water circuit 40. As a result, the outdoor heat exchanger 23 functions as a condenser, and the indoor heat exchanger 31 and the water-refrigerant heat exchanger 51 function as evaporators.

[0069] The rotation speed of the compressor 21 and the flow rate of the circulation pump 44 are determined based on information about the indoor load or the water It is determined according to information relating to the heat load of the circuit 30. Here, an example will be described in which all the indoor units (first indoor unit 3, second indoor unit 4) perform indoor cooling.

[0070] The refrigerant compressed by the compressor 21 to a high temperature and high pressure is discharged from the compressor 21, flows through the discharge pipe 61, and flows into the four-way valve 22, and then flows from the four-way valve 22 into the refrigerant piping 62 and into the outdoor heat exchanger 23. The refrigerant that has flowed into the outdoor heat exchanger 23 exchanges heat with outside air that has been drawn into the outdoor unit 2 by the rotation of the outdoor fan 29, and is condensed.

[0071] The refrigerant flowing out from the outdoor heat exchanger 23 flows through the outdoor unit liquid pipe 63 and passes through the outdoor expansion valve 24. A portion of the refrigerant that has passed through the outdoor expansion valve 24 is decompressed when it flows through the liquid pipe 36 and passes through the first expansion valve 33. The other portion of the refrigerant that has passed through the outdoor expansion valve 24 is decompressed when it flows through the liquid branch pipe 16 and passes through the second expansion valve 52.

[0072] Here, the outdoor expansion valve 24 is, for example, fully open. The first expansion valve 33 is opened so that the evaporation pressure corresponds to the evaporation temperature in the indoor heat exchanger 31. More specifically, the evaporation temperature converted from the evaporation pressure, which is the value detected by the low-pressure sensor 73, is lower than the lowest indoor temperature (set temperature) set for the first indoor unit 3 (e.g., 18°C). The second expansion valve 52 is opened so that the evaporation pressure corresponds to the evaporation temperature in the water-refrigerant heat exchanger 51 to achieve the set temperature during cooling operation in the room where the second indoor unit 4 is installed. More specifically, the evaporation temperature converted from the evaporation pressure, which is the value detected by the low-pressure sensor 73, and the temperature of the water flowing out of the water-refrigerant heat exchanger 51, which is the value detected by the feed temperature sensor 80, are lower than the lowest air-conditioning temperature (set temperature) set for the second indoor unit 4 (e.g., 18°C).

[0073] The refrigerant that has passed through the first expansion valve 33 flows into the indoor heat exchanger 31 via the indoor unit liquid pipe 38. The refrigerant that has flowed into the indoor heat exchanger 31 exchanges heat with indoor air that has been drawn into the first indoor unit 3 by the rotation of the indoor fan 32 and evaporates, thereby cooling the room in which the first indoor unit 3 is installed. The refrigerant that has flowed out of the indoor heat exchanger 31 flows into the outdoor unit gas pipe 64 via the indoor unit gas pipe 39 and gas pipe 37, and returns to the compressor 21.

[0074] The refrigerant that has passed through the second expansion valve 52 flows into the liquid refrigerant inlet / outlet 51a of the water-refrigerant heat exchanger 51 via the liquid branch pipe 16. The refrigerant that has flowed into the liquid refrigerant inlet / outlet 51a passes through the refrigerant-side flow path 511 and exchanges heat with water flowing through the water-side flow path 512, thereby evaporating, and flows from the gas refrigerant inlet / outlet 51b of the water-refrigerant heat exchanger 51 through the gas branch pipe 17 into the outdoor unit gas pipe 64. The refrigerant that has flowed into the outdoor unit gas pipe 64 flows through the four-way valve 22, refrigerant piping 66, accumulator 25, and suction pipe 65, and is sucked into the compressor 21 and compressed again.

[0075] On the other hand, the water cooled while flowing through the water-side flow path 512 flows into the first water piping 11 from the water outlet 51d of the water-refrigerant heat exchanger 51. The water that has flowed into the first water piping 11 flows into the indoor heat exchanger 41 of the second indoor unit 4 via the open on-off valve 43, and cools the indoor air passing through the indoor heat exchanger 41 by the rotation of the indoor fan 42. This cools the room in which the second indoor unit 4 is installed.

[0076] The water flowing out from the indoor heat exchanger 41 of each second indoor unit 4 is drawn into the circulation pump 44 via the second water pipe 12. The water drawn into the circulation pump 44 is sent to the water inlet 51c of the water-refrigerant heat exchanger 51, passes through the water-side flow path 512, and is cooled again by the refrigerant flowing in the refrigerant-side flow path 511, and then flows out from the water outlet 51d toward the second indoor unit 4.

[0077] (Heating operation) When the refrigeration cycle apparatus 100 performs heating operation (heating operation mode), the four-way valve 22 is switched to the state shown by the dashed lines in Fig. 1, i.e., the state where port a and port d are connected and port b and port c are connected, and the compressor 21 and the circulation pump 44 are driven in this state. Driving the compressor 21 causes refrigerant to circulate through the refrigerant circuit 20, and driving the circulation pump 44 causes water to circulate through the water circuit 40. As a result, the outdoor heat exchanger 23 functions as an evaporator, and the indoor heat exchanger 31 and the water-refrigerant heat exchanger 51 function as condensers.

[0078] The rotation speed of the compressor 21 and the flow rate of the circulation pump 44 are determined according to information about the indoor load or information about the heat load of the water circuit 40. Here, an example will be described in which all indoor units (first indoor unit 3, second indoor unit 4) heat the room.

[0079] The refrigerant compressed by the compressor 21 to a high temperature and high pressure is discharged from the compressor 21, flows through the discharge pipe 61, and flows into the four-way valve 22, and from the four-way valve 22 flows into the gas pipe 37 and the gas branch pipe 17 via the outdoor unit gas pipe 64.

[0080] The refrigerant that has flowed into the gas pipe 37 flows into the indoor heat exchanger 31 via the indoor unit gas pipe 39. The refrigerant that has flowed into the indoor heat exchanger 31 exchanges heat with the indoor air that has been drawn into the first indoor unit 3 by the rotation of the indoor fan 32 and condenses, thereby heating the room in which the first indoor unit 3 is installed. The refrigerant that has flowed out of the indoor heat exchanger 31 is decompressed by the first expansion valve 33, and flows into the outdoor unit liquid pipe 63 via the indoor unit liquid pipe 38 and liquid pipe 36.

[0081] At this time, the opening degree of the first expansion valve 33 is set so that the subcooling (degree of supercooling) of the refrigerant flowing out of the indoor heat exchanger 31 becomes a target subcooling, more specifically, so that the refrigerant flowing into the first expansion valve 33 becomes a single-phase liquid refrigerant that has been completely condensed in the indoor heat exchanger 31. The subcooling of the refrigerant flowing out of the indoor heat exchanger 31 is the difference between the condensing temperature converted from the detection value of the high-pressure sensor 71 and the detection value of the third refrigerant temperature sensor 82. The target subcooling is a value that is set in advance through testing or the like so that the refrigerant flowing into the first expansion valve 33 becomes a single-phase liquid refrigerant that has been completely condensed in the indoor heat exchanger 31.

[0082] On the other hand, the refrigerant that has flowed into the gas branch pipe 17 flows into the gas refrigerant inlet / outlet 51b of the water-refrigerant heat exchanger 51. The refrigerant that has flowed into the gas refrigerant inlet / outlet 51b passes through the refrigerant-side flow path 511 and heats the water flowing in the water-side flow path 512. The refrigerant condensed by heat exchange with the water flowing in the water-side flow path 512 flows out from the liquid-side inlet / outlet 51a of the water-refrigerant heat exchanger 51 into the liquid branch pipe 16, is decompressed by the second expansion valve 52, and flows into the outdoor unit liquid pipe 63.

[0083] At this time, the opening degree of the second expansion valve 52 is set so that the subcooling (degree of supercooling) of the refrigerant flowing out of the water-refrigerant heat exchanger 51 becomes a target subcooling to achieve the set temperature during heating operation in the room where the second indoor unit 4 is installed, more specifically, so that the refrigerant flowing into the second expansion valve 52 becomes a single-phase liquid refrigerant that has been completely condensed in the water-refrigerant heat exchanger 51. The subcooling of the refrigerant flowing out of the water-refrigerant heat exchanger 51 is the difference between the condensing temperature converted from the detection value of the high-pressure sensor 71 and the detection value of the second refrigerant temperature sensor 79. The target subcooling value is set in advance through testing or the like, and is a value at which the refrigerant flowing into the second expansion valve 52 becomes a single-phase liquid refrigerant that has been completely condensed in the water-refrigerant heat exchanger 51.

[0084] The water heated while flowing through the water-side flow path 512 flows into the first water piping 11 from the water outlet 51d of the water-refrigerant heat exchanger 51. The water that has flowed into the first water piping 11 flows into the indoor heat exchanger 41 via the open on-off valve 43, and heats the indoor air passing through the indoor heat exchanger 41 by the rotation of the indoor fan 42. This heats the room in which the second indoor unit 4 is installed.

[0085] The water flowing out of the indoor heat exchanger 41 flows into the second water pipe 12 and is sucked into the circulation pump 44. The water sucked into the circulation pump 44 is sent to the water inlet 51c of the water-refrigerant heat exchanger 51, passes through the water-side flow path 512, and is heated again by the refrigerant flowing in the refrigerant-side flow path 511, and then flows out from the water outlet 51d toward the second indoor unit 4.

[0086] Meanwhile, the refrigerant that has flowed into the outdoor unit liquid pipe 63 passes through the outdoor expansion valve 24 and flows into the outdoor heat exchanger 23. The refrigerant that has flowed into the outdoor heat exchanger 23 evaporates by exchanging heat with outside air that has been drawn into the outdoor unit 2 by the rotation of the outdoor fan 29. The refrigerant that has flowed out of the outdoor heat exchanger 23 flows through the refrigerant piping 62, and is drawn into the compressor 21 via the four-way valve 22, refrigerant piping 66, accumulator 25, and suction pipe 65, where it is compressed again. The opening of the outdoor expansion valve 24 is controlled to be fully open or to an opening such that the temperature of the refrigerant discharged from the compressor 21 becomes a target discharge temperature.

[0087] [Controller details] In this type of refrigeration cycle system, if a liquid refrigerant flows into the compressor, so-called liquid compression occurs, which leads to a decrease in the reliability of the compressor. To prevent the liquid refrigerant from flowing into the compressor, it is necessary to set a target value for the evaporation temperature so that the degree of superheat of the refrigerant drawn into the compressor is a predetermined value, and to control the refrigerant circuit so that the evaporation temperature reaches the target value.

[0088] On the other hand, in a refrigeration cycle equipped with a direct expansion unit or a partial expansion unit as a user unit, for example, during cooling operation, the target value of the evaporation temperature can be set according to the load of the operating user unit, thereby achieving the required capacity. In other words, in order for the room temperature of the air-conditioned space to reach the set temperature, the evaporation temperature must be lower than the target temperature. On the other hand, to ensure the reliability of the compressor, the evaporation temperature must be lower than the temperature of the heat medium with which the refrigerant is heat-exchanged.

[0089] However, when an expansion unit with a different heat medium (air and water) or control target (room temperature and water temperature) that is the heat exchange target is connected as the user unit and is operated, it may not be possible to lower the evaporation temperature of the refrigerant below the temperature of the heat medium that is the heat exchange target.

[0090] That is, in a direct expansion unit, the object of heat exchange is air and the control target is room temperature, whereas in a partial expansion unit, the object of heat exchange is water and the control target is water temperature. Therefore, for example, if the rotation speed of the compressor of a partial expansion unit is controlled based on the difference between room temperature and the set temperature in the same way as a direct expansion unit during cooling operation, the evaporation temperature of the refrigerant will not reach the target value because the water temperature is lower than room temperature, and the required capacity cannot be exerted, which may reduce indoor comfort or reduce the reliability of the compressor due to the inflow of liquid phase refrigerant.

[0091] Furthermore, for example, if the rotation speed of the room temperature compressor of the intermediate expansion unit is controlled based on the difference between the room temperature and the set temperature in the same way as the direct expansion unit during heating operation, the condensation temperature of the refrigerant will not reach the target value because the water temperature is higher than the room temperature, and the required capacity cannot be achieved, which may result in a decrease in indoor comfort.

[0092] In view of the above circumstances, in this embodiment, the control device 30 is configured as follows, with the aim of ensuring the reliability of the compressor while minimizing any decrease in comfort, regardless of whether a direct expansion unit or a partial expansion unit is connected as the user unit.

[0093] 3 is a functional block diagram showing the configuration of the CPU 91 of the control device 90. The CPU 91 has a terminal identifying unit 911 and a target temperature setting unit 912.

[0094] The terminal identification unit 911 identifies whether the operating user side unit is a direct expansion unit (first indoor unit 3), a partial expansion unit (second indoor unit 4), or both a direct expansion unit (first indoor unit 3) and a partial expansion unit (second indoor unit 4).

[0095] The terminal identification unit 911 is presumed to be able to identify the unit that is the sender of information received via the communication unit 93. As a method for identifying user-side units in operation, if the information regarding the indoor load received via the communication unit 93 only relates to the indoor load of the first indoor unit 3, the terminal identification unit 911 determines that the only user-side unit in operation is the first indoor unit 3. Furthermore, if the information regarding the indoor load received via the communication unit 93 only relates to the indoor load of the second indoor unit 4, the terminal identification unit 911 determines that the only user-side unit in operation is the second indoor unit 4. Furthermore, if the information regarding the indoor load received via the communication unit 93 relates to the indoor loads of both the first indoor unit 3 and the second indoor unit 4, the terminal identification unit 911 determines that the both user-side units in operation are the first indoor unit 3 and the second indoor unit 4. Note that when information regarding the heat load of the water circuit 40 is received, the terminal identification unit 911 determines that the second indoor unit 4 is in operation.

[0096] Furthermore, the terminal identification unit 911 identifies whether the second indoor unit 4 is an indoor unit equipped with a temperature setting unit 45 and a room temperature sensor 84 (hereinafter also referred to as a sensor-equipped indoor unit), or an indoor unit not equipped with a temperature setting unit 45 and a room temperature sensor 84 (hereinafter also referred to as a sensorless indoor unit). When the terminal identification unit 911 receives information related to the indoor load from the second indoor unit 4, it identifies the second indoor unit 4 as a sensor-equipped indoor unit, and when it receives information related to the heat load of the water circuit 40 from the relay unit 50 (receiving unit 53), it identifies the second indoor unit 4 as a sensorless indoor unit.

[0097] (Setting the target evaporation temperature and its upper limit) The target temperature setting unit 912 sets an upper limit for the temperature of the refrigerant that flows into the water-refrigerant heat exchanger 51 when performing cooling operation to cool the indoor air. This upper limit for the refrigerant temperature determines the upper limit for the evaporation temperature of the refrigerant that flows through the water-refrigerant heat exchanger 51, which functions as an evaporator during cooling operation, and more specifically, is a temperature that prevents liquid-phase refrigerant from flowing into the compressor 21.

[0098] The target temperature setting unit 912 sets the upper limit of the target value in a first upper limit temperature setting mode when the utilization side unit is a direct expansion unit (first indoor unit 3), and sets the upper limit of the target value in a second upper limit temperature setting mode different from the first upper limit temperature setting mode when the utilization side unit is a direct expansion unit (second indoor unit 4).

[0099] In the following description, the upper limit of the refrigerant temperature set in the first upper limit temperature setting mode is also referred to as the first target upper limit, and the upper limit of the refrigerant temperature set in the second upper limit temperature setting mode is also referred to as the second target upper limit.

[0100] In the first upper limit temperature setting mode, the target temperature setting unit 912 calculates a target value for the temperature of the refrigerant flowing into the indoor heat exchanger 31 based on the difference between the temperature detected by the room temperature sensor 83 of the first indoor unit 3 and the temperature set by the temperature setting unit 35 of the first indoor unit 3 (i.e., the indoor load of the first indoor unit 3). The CPU 91 controls the rotation speed of the compressor 21 so that the evaporation temperature converted from the evaporation pressure, which is the detection value of the low-pressure sensor 73, becomes the calculated target value. The target temperature setting unit 912 also sets an upper limit (first target upper limit) of the target value according to the temperature set by the temperature setting unit 35. Specifically, the first target upper limit is, for example, (set temperature -2°C). If the calculated target value exceeds the first target upper limit, the CPU 91 controls the rotation speed of the compressor 21 so that the evaporation temperature becomes the first target upper limit.

[0101] As a result, the evaporation temperature of the refrigerant becomes lower than the set temperature, which prevents a decrease in the reliability of the compressor 21 due to the inflow of liquid phase refrigerant while suppressing a decrease in the comfort of the indoor space of the first indoor unit 3.

[0102] When the second indoor unit 4 is a sensor-equipped indoor unit, the target temperature setting unit 912 sets a target value for the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51 in the second upper limit temperature setting mode based on the difference between the temperature detected by the room temperature sensor 84 of the second indoor unit 4 and the temperature set by the temperature setting unit 45 of the second indoor unit 4 (i.e., the indoor load of the second indoor unit 4). The CPU 91 controls the rotation speed of the compressor 21 so that the evaporation temperature, which is the detection value of the first refrigerant temperature sensor 78, becomes the set target value. The target temperature setting unit 912 also sets an upper limit (second target upper limit) of the target value according to the detection temperature of the return temperature sensor 81. Specifically, the second target upper limit is, for example, (return water temperature -2°C). If the calculated target value exceeds the second target upper limit, the CPU 91 controls the rotation speed of the compressor 21 so that the evaporation temperature becomes the second target upper limit.

[0103] As a result, the evaporation temperature of the refrigerant becomes lower than the return water temperature, which prevents a decrease in the reliability of the compressor 21 due to the inflow of liquid phase refrigerant while suppressing a decrease in the comfort of the indoor space of the second indoor unit 4.

[0104] On the other hand, when the second indoor unit 4 is a sensorless indoor unit, the target temperature setting unit 912 sets a target value for the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51 as a second upper limit temperature setting mode based on the difference between the temperature detected by the supply temperature sensor 80 and the temperature detected by the return temperature sensor 81 (i.e., the thermal load of the water circuit 40). The CPU 91 controls the rotation speed of the compressor 21 so that the evaporation temperature, which is the value detected by the first refrigerant temperature sensor 78, becomes the set target value. The target temperature setting unit 912 also sets an upper limit (second target upper limit) of the target value according to the temperature detected by the supply temperature sensor 80. Specifically, the second target upper limit is, for example, (supply water temperature -2°C). If the calculated target value exceeds the second target upper limit, the CPU 91 controls the rotation speed of the compressor 21 so that the evaporation temperature becomes the second target upper limit.

[0105] As a result, the evaporation temperature of the refrigerant becomes lower than the temperature of the supply water, which prevents a decrease in the comfort of the indoor space of the second indoor unit 4 while preventing a decrease in the reliability of the compressor 21 due to the inflow of liquid phase refrigerant.

[0106] Furthermore, when both the first indoor unit 3 and the second indoor unit 4 are operating, the target temperature setting unit 912 sets the upper limit of the target value for the evaporation temperature to the lower of the upper limit of the target value set in the first upper limit temperature setting mode (first target upper limit) or the upper limit of the target value set in the second upper limit temperature setting mode (second target upper limit). This ensures the comfort of the indoor space of the second indoor unit 4 and the reliability of the compressor 21.

[0107] FIG. 4 is a flowchart showing an example of a procedure executed by the control device 90 for determining the upper limit of the target value of the evaporation temperature.

[0108] When the refrigeration cycle device 100 performs cooling operation, the control device 90 determines whether the indoor unit in operation is the first indoor unit 3, the second indoor unit 4, or both the first indoor unit 3 and the second indoor unit 4, and, depending on the determination result, determines whether to use the first upper limit temperature setting mode or the second upper limit temperature setting mode as the setting mode for the upper limit of the target value of the evaporation temperature.

[0109] 4, the control device 90 first determines whether only the direct expansion unit (first indoor unit 3) is operating (ST101). If only the direct expansion unit is operating (Yes in ST101), the control device 90 sets the upper limit of the target value of the evaporation temperature in the first upper limit temperature setting mode (ST105).

[0110] On the other hand, when the intermediate expansion unit (second indoor unit 4) is operating (No in ST101), the control device 90 determines whether the operating indoor unit is the intermediate expansion unit only (ST102). When the operating indoor unit is the intermediate expansion unit only (Yes in ST102), the control device 90 sets the upper limit of the target value of the evaporation temperature in the second upper limit temperature setting mode (ST104).

[0111] When both the direct expansion unit and the intermediate expansion unit are in operation (No in ST102), the control device 90 compares the upper limit of the target value of the evaporation temperature when set in the first upper limit temperature setting mode (first target upper limit) with the upper limit of the target value of the evaporation temperature when set in the second upper limit temperature setting mode (second target upper limit) (ST103). Then, when the first target upper limit is lower than the second target upper limit (Yes in ST103), the first upper limit temperature setting mode is executed (ST105), and when the second target upper limit is lower than the first target upper limit (No in ST103), the second upper limit temperature setting mode is executed (ST104).

[0112] (Setting the target value and lower limit of the condensation temperature) The target temperature setting unit 912 sets a lower limit for the temperature of the refrigerant that flows into the water-refrigerant heat exchanger 51 when performing heating operation to heat the indoor air. This lower limit for the refrigerant temperature determines the lower limit for the condensation temperature of the refrigerant that flows through the water-refrigerant heat exchanger 51, which functions as a condenser during heating operation, and more specifically, is a temperature that can prevent a decrease in the comfort of the indoor space.

[0113] The target temperature setting unit 912 sets the lower limit of the target value in a first lower limit temperature setting mode when the utilization side unit is a direct expansion unit (first indoor unit 3), and sets the lower limit of the target value in a second lower limit temperature setting mode different from the first lower limit temperature setting mode when the utilization side unit is a direct expansion unit (second indoor unit 4).

[0114] In the following description, the lower limit of the refrigerant temperature set in the first lower limit temperature setting mode is also referred to as the first target lower limit, and the lower limit of the refrigerant temperature set in the second lower limit temperature setting mode is also referred to as the second target lower limit.

[0115] In the first lower limit temperature setting mode, the target temperature setting unit 912 calculates a target value for the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51 based on the difference between the temperature detected by the room temperature sensor 83 of the first indoor unit 3 and the temperature set by the temperature setting unit 35 of the first indoor unit 3 (i.e., the indoor load of the first indoor unit 3). The CPU 91 controls the rotation speed of the compressor 21 so that the condensing temperature converted from the condensing pressure, which is the detection value of the high-pressure sensor 71, becomes the calculated target value. The target temperature setting unit 912 also sets a lower limit (first target lower limit) of the target value according to the temperature set by the temperature setting unit 35. Specifically, the first target lower limit is, for example, (set temperature + 2°C). If the calculated target value falls below the first target lower limit, the CPU 91 controls the rotation speed of the compressor 21 so that the condensing temperature becomes the first target lower limit.

[0116] This makes it possible to set the condensation temperature of the refrigerant based on the indoor temperature, making it possible to prevent a decrease in comfort in the indoor space of the first indoor unit 3.

[0117] When the second indoor unit 4 is a sensor-equipped indoor unit, the target temperature setting unit 912 sets a target value for the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51 in the second lower limit temperature setting mode based on the difference between the temperature detected by the room temperature sensor 84 of the second indoor unit 4 and the temperature set by the temperature setting unit 45 of the second indoor unit 4 (i.e., the indoor load of the second indoor unit 4). The CPU 91 controls the rotation speed of the compressor 21 so that the condensing temperature, which is the value detected by the second refrigerant temperature sensor 79, becomes the calculated target value. The target temperature setting unit 912 also sets a lower limit (second target lower limit) of the target value according to the temperature detected by the return temperature sensor 81. Specifically, the second target lower limit is, for example, (set temperature + 2°C). If the calculated target value falls below the second target lower limit, the CPU 91 controls the rotation speed of the compressor 21 so that the condensing temperature becomes the second target lower limit.

[0118] This makes it possible to set the condensation temperature of the refrigerant for the return water temperature of the water circuit 40, which is higher than room temperature, so that the decrease in comfort of the indoor space of the second indoor unit 4 can be suppressed.

[0119] On the other hand, when the second indoor unit 4 is a sensorless indoor unit, the target temperature setting unit 912 sets a target value for the temperature of the refrigerant flowing into the water-refrigerant heat exchanger 51 in a second lower limit temperature setting mode based on the difference between the temperature detected by the supply temperature sensor 80 and the temperature detected by the return temperature sensor 81 (i.e., the thermal load of the water circuit 40). The CPU 91 controls the rotation speed of the compressor 21 so that the condensing temperature, which is the value detected by the second refrigerant temperature sensor 79, becomes the calculated target value. The target temperature setting unit 912 also sets a lower limit (second target lower limit) of the target value according to the temperature detected by the supply temperature sensor 80. Specifically, the second target lower limit is, for example, (set temperature + 2°C). If the calculated target value falls below the second target lower limit, the CPU 91 controls the rotation speed of the compressor 21 so that the condensing temperature becomes the second target lower limit.

[0120] This makes it possible to set the condensation temperature of the refrigerant for the highest supply water temperature in the water circuit 40, so that a decrease in comfort in the indoor space of the second indoor unit 4 can be suppressed.

[0121] Furthermore, when both the first indoor unit 3 and the second indoor unit 4 are operating, the target temperature setting unit 912 sets the lower limit of the target value for the condensing temperature to the higher of the lower limit of the target value set in the first lower limit temperature setting mode (first target lower limit) or the lower limit of the target value set in the second lower limit temperature setting mode (second target lower limit). This ensures comfort in the indoor space of the second indoor unit 4.

[0122] FIG. 5 is a flowchart showing an example of a procedure executed by the control device 90 for determining the lower limit of the target value of the condensing temperature.

[0123] When the refrigeration cycle apparatus 100 performs heating operation, the control device 90 determines whether the indoor unit in operation is the first indoor unit 3, the second indoor unit 4, or both the first indoor unit 3 and the second indoor unit 4, and, depending on the determination result, determines whether to adopt the first lower limit temperature setting mode or the second lower limit temperature setting mode as the setting mode for the lower limit of the target value of the condensing temperature.

[0124] 5, the control device 90 first determines whether only the direct expansion unit (first indoor unit 3) is operating (ST201). If only the direct expansion unit is operating (Yes in ST201), the control device 90 sets the lower limit of the target value of the condensing temperature in the first lower limit temperature setting mode (ST205).

[0125] On the other hand, when the intermediate expansion unit (second indoor unit 4) is operating (No in ST201), the control device 90 determines whether the operating indoor unit is the intermediate expansion unit only (ST202). When the operating indoor unit is the intermediate expansion unit only (Yes in ST202), the control device 90 sets the lower limit of the target value of the condensing temperature in the second lower limit temperature setting mode (ST204).

[0126] When both the direct expansion unit and the intermediate expansion unit are operating (No in ST202), the control device 90 compares the lower limit of the target value of the condensing temperature when set in the first lower limit temperature setting mode (first target lower limit) with the lower limit of the target value of the condensing temperature when set in the second lower limit temperature setting mode (second target lower limit) (ST203). When the first target lower limit is higher than the second target lower limit (Yes in ST203), the first lower limit temperature setting mode is executed (ST205), and when the second target lower limit is higher than the first target lower limit (No in ST203), the second lower limit temperature setting mode is executed (ST204).

[0127] (Room temperature control and water temperature control) Subsequently, when executing the second upper limit temperature setting mode, the control mode for the rotation speed of the compressor 21 may be changed depending on whether the second indoor unit 4 is a sensor-equipped indoor unit or a sensorless indoor unit. In this embodiment, if the second indoor unit 4 is a sensor-equipped indoor unit, the room temperature control mode is executed to control the rotation speed of the compressor 21, and if the second indoor unit 4 is a sensorless indoor unit, the water temperature control mode is executed to control the rotation speed of the compressor 21.

[0128] When the intermediate expansion unit is the control target, the rotation speed of the compressor 21 is determined according to information about the indoor load of the second indoor unit 4 or information about the heat load of the water circuit 40. The indoor load of the second indoor unit 4 is calculated based on the difference between the indoor temperature detected by the room temperature sensor 84 and the set temperature input to the temperature setting unit 45.

[0129] Meanwhile, the information relating to the thermal load of the water circuit 40 includes the supply water temperature, which is the temperature detected by the supply temperature sensor 80 in the water circuit 40, the return water temperature, which is the temperature detected by the return temperature sensor 81, and an input instruction value (temperature setting value) from the user received by the receiver 53 of the relay unit 50. The thermal load of the water circuit 40 is calculated based on these water temperatures and the input instruction value.

[0130] Information relating to the indoor load of the second indoor unit 4 and information relating to the heat load of the water circuit 40 are transmitted to the control device 90 at a predetermined cycle (the update interval for the rotation speed control of the compressor 21). The control device 90 executes either a room temperature control mode in which the rotation speed of the compressor 21 is controlled based on information relating to the indoor load of the second indoor unit 4, or a water temperature control mode in which the rotation speed of the compressor 21 is controlled based on information relating to the heat load of the water circuit 40.

[0131] Whether the room temperature control mode or the water temperature control mode is to be executed is determined according to the specifications or model of the second indoor unit 4 that received the operation command. For example, if the second indoor unit 4 that received the operation command is equipped with a room temperature sensor 84, the control device 90 will execute the room temperature control mode, thereby controlling the rotation speed of the compressor 21 so that the indoor space in which the second indoor unit 4 is installed will be at the set temperature input to the temperature setting unit 45. On the other hand, if the second indoor unit 4 is not equipped with a room temperature sensor 84, the control device 90 will execute the water temperature control mode, thereby controlling the rotation speed of the compressor 21 so that the indoor space in which the second indoor unit 4 is installed will be at the set temperature corresponding to the input command from the user received by the receiving unit 53.

[0132] FIG. 6 is a flowchart showing an example of a procedure executed by the control device 90 to determine the control mode for the rotation speed of the compressor 21.

[0133] The control device 90 first determines whether the second indoor unit 4 (intermediate expansion unit) is operating (ST301). If the second indoor unit 4 is not operating (No in ST301), the processing ends. On the other hand, if the second indoor unit 4 is operating (Yes in ST301), the control device 90 determines whether information regarding the indoor load has been received from the second indoor unit 4 (ST302).

[0134] The control device 90 executes the room temperature control mode when it receives information about the indoor load from the second indoor unit 4 (Yes in ST302), and executes the water temperature control mode when it cannot confirm receipt of information about the indoor load (No in ST302).

[0135] (Room temperature control mode) In room temperature control mode, the control device 90 uses a pre-stored indoor temperature setting to calculate the indoor load based on the difference between the indoor temperature and the set temperature (ST303). The indoor temperature setting is input by the user via the temperature setting unit 45 installed in the second indoor unit 4. The indoor temperature is the temperature detected by the room temperature sensor 84 installed in the second indoor unit 4. The input set temperature and the detected indoor temperature are stored in the memory unit 92 of the control device 90. The control device 90 acquires the set temperature and indoor temperature at a predetermined interval, and updates the set temperature and indoor temperature stored in the memory unit 92 to the latest set temperature and detected temperature, respectively.

[0136] The controller 90 calculates the indoor load, which is the difference between the set temperature and the indoor temperature, and executes a room temperature control mode in which the rotation speed of the compressor 21 is controlled based on the indoor load of the second indoor unit 4 (ST304).

[0137] (Water temperature control mode) On the other hand, in the water temperature control mode, the control device 90 stores a target temperature for the water temperature of the water circuit 40, and calculates the heat load of the water circuit 40 based on the difference between the water temperature of the water circuit 40 and the target temperature (ST305).

[0138] The target water temperature of the water circuit 40 is a target value for the temperature of water flowing out of the water-refrigerant heat exchanger 51, and is set based on a user input instruction received by the receiver 53 of the relay unit 50. The water temperature of the water circuit 40 is a detection value of the supply temperature sensor 80, which detects the temperature of water flowing out of the water-refrigerant heat exchanger 51. The set target temperature and the detected water temperature of the water circuit 40 are stored in the memory 92 of the control device 90. The control device 90 acquires the target temperature and the water temperature of the water circuit 40 at a predetermined interval and updates the water temperatures stored in the memory 92 to the latest water temperatures. The target water temperature of the water circuit 40 may also be calculated based on the difference between the detection value of the supply temperature sensor 80 and the detection value of the return temperature sensor 81.

[0139] The control device 90 calculates the heat load of the water circuit 40 based on the difference between the water temperature of the water circuit 40 and the target temperature, and executes a water temperature control mode in which the rotation speed of the compressor 21 is controlled based on the heat load (ST306).

[0140] As described above, by executing either the room temperature control mode, which controls the rotation speed of the compressor 21 based on information related to the indoor load of the second indoor unit 4, or the water temperature control mode, which controls the rotation speed of the compressor 21 based on information related to the thermal load of the water circuit 30, the rotation speed of the compressor 21 can be controlled appropriately according to the specifications or model of the second indoor unit 4 connected to the relay unit 50.

[0141] Although the embodiments of the present invention have been described above, it goes without saying that the present invention is not limited to the above-described embodiments and that various modifications can be made.

[0142] For example, in the above embodiment, a refrigeration cycle device having both a direct expansion unit (first indoor unit 3) and a partial expansion unit (second indoor unit 4) as the user side units has been described as an example, but the present invention is not limited to this, and can also be applied to a refrigeration cycle device having only a direct expansion unit as the user side unit, or a refrigeration cycle device having only a partial expansion unit as the user side unit.

[0143] In the above embodiment, a refrigeration cycle device capable of performing cooling operation and heating operation has been described as an example, but the present invention can also be applied to a refrigeration cycle device that is dedicated to cooling operation or a refrigeration cycle device that is dedicated to heating operation.

[0144] In the above embodiment, the second indoor unit 4 is an air-conditioning fan coil unit (FCU) as an indoor unit, but is not limited to this, and a hot water supply unit, a panel heater, or the like may also be used. [Explanation of symbols]

[0145] 2...Outdoor unit (heat source module) 3...First indoor unit (direct expansion unit) 4...Second indoor unit (expansion unit, indoor unit) 21...Compressor 22...Four-way valve 23…Outdoor heat exchanger 31,41…Indoor heat exchanger 35,45...Temperature setting section 40…Water circuit (heat medium circuit) 50...Relay unit 80...Forward temperature sensor 81...Return temperature sensor 83, 84...Room temperature sensor 90...Control device 100...Refrigeration cycle device 911...Terminal Identification Unit 912…Target temperature setting section

Claims

1. a user side unit having a refrigerant heat exchanger that exchanges heat between a refrigerant and a heat exchange target; a heat source module having a compressor and a control device that controls the rotation speed of the compressor so that the temperature of the refrigerant flowing into the refrigerant heat exchanger becomes a target value; the control device has a target temperature setting unit that sets an upper limit of the target value when performing a cooling operation to cool the heat exchange target, The target temperature setting unit sets the upper limit of the target value in a first upper limit temperature setting mode when the user side unit to be operated is a direct expansion unit, and sets the upper limit of the target value in a second upper limit temperature setting mode different from the first upper limit temperature setting mode when the user side unit to be operated is a direct expansion unit. Refrigeration cycle equipment.

2. The refrigeration cycle device according to claim 1, the user-side unit is a direct expansion unit including a heat exchange target sensor that detects the temperature of the heat exchange target and a temperature setting unit that can input a set temperature; In the first upper limit temperature setting mode, the target temperature setting unit calculates the target value based on a difference between the detected temperature of the heat exchange target sensor and the set temperature, and sets an upper limit of the target value according to the set temperature. Refrigeration cycle equipment.

3. The refrigeration cycle device according to claim 1, The user-side unit is an intermediate expansion unit including: a heat medium circuit that circulates a heat medium between a relay unit having a heat medium heat exchanger that is the refrigerant heat exchanger and an indoor unit having an indoor heat exchanger; a return temperature sensor that detects the temperature of the heat medium flowing into the heat medium heat exchanger; a room temperature sensor that detects the temperature of indoor air flowing into the indoor heat exchanger; and a temperature setting unit that can input a set temperature; In the second upper limit temperature setting mode, the target temperature setting unit sets the target value based on a difference between the temperature detected by the room temperature sensor and the set temperature, and sets an upper limit of the target value according to the temperature detected by the return temperature sensor. Refrigeration cycle equipment.

4. The refrigeration cycle device according to claim 1, The user side unit is an intermediate expansion unit including a heat medium circuit that circulates a heat medium between an intermediate unit having a heat medium heat exchanger that is the refrigerant heat exchanger and an indoor unit having an indoor heat exchanger, a forward temperature sensor that detects the temperature of the heat medium flowing out of the heat medium heat exchanger, and a return temperature sensor that detects the temperature of the heat medium flowing into the heat medium heat exchanger, In the second upper limit temperature setting mode, the target temperature setting unit sets the target value based on a difference between the temperature detected by the forward temperature sensor and the temperature detected by the return temperature sensor, and sets an upper limit of the target value according to the temperature detected by the forward temperature sensor. Refrigeration cycle equipment.

5. The refrigeration cycle apparatus according to any one of claims 1 to 4, the heat source module is connected to a plurality of user-side units including both the direct expansion unit and the intermediate expansion unit, The target temperature setting unit sets the upper limit of the target value to the lower of the upper limit of the target value set in the first upper limit temperature setting mode and the upper limit of the target value set in the second upper limit temperature setting mode. Refrigeration cycle equipment.

6. a user side unit having a refrigerant heat exchanger that exchanges heat between a refrigerant and a heat exchange target; a heat source module having a compressor and a control device that controls the rotation speed of the compressor so that the temperature of the refrigerant flowing into the refrigerant heat exchanger becomes a target value; The control device has a target temperature setting unit that sets a lower limit of the target value when performing a heating operation to heat the heat exchange target, The target temperature setting unit sets the lower limit of the target value in a first lower limit temperature setting mode when the user side unit to be operated is a direct expansion unit, and sets the lower limit of the target value in a second lower limit temperature setting mode different from the first lower limit temperature setting mode when the user side unit to be operated is a direct expansion unit. Refrigeration cycle equipment.

7. The refrigeration cycle device according to claim 6, the user-side unit is a direct expansion unit including a heat exchange target sensor that detects the temperature of the heat exchange target and a temperature setting unit that can input a set temperature; In the first lower limit temperature setting mode, the target temperature setting unit calculates the target value based on a difference between the detected temperature of the heat exchange target sensor and the set temperature, and sets a lower limit of the target value according to the set temperature. Refrigeration cycle equipment.

8. The refrigeration cycle device according to claim 6, The user-side unit is an intermediate expansion unit including: a heat medium circuit that circulates a heat medium between a relay unit having a heat medium heat exchanger that is the refrigerant heat exchanger and an indoor unit having an indoor heat exchanger; a return temperature sensor that detects the temperature of the heat medium flowing into the heat medium heat exchanger; a room temperature sensor that detects the temperature of indoor air flowing into the indoor heat exchanger; and a temperature setting unit that can input a set temperature; In the second lower limit temperature setting mode, the target temperature setting unit sets the target value based on a difference between the temperature detected by the room temperature sensor and the set temperature, and sets a lower limit of the target value according to the temperature detected by the return temperature sensor. Refrigeration cycle equipment.

9. The refrigeration cycle device according to claim 6, The user side unit is an intermediate expansion unit including a heat medium circuit that circulates a heat medium between an intermediate unit having a heat medium heat exchanger that is the refrigerant heat exchanger and an indoor unit having an indoor heat exchanger, a forward temperature sensor that detects the temperature of the heat medium flowing out of the heat medium heat exchanger, and a return temperature sensor that detects the temperature of the heat medium flowing into the heat medium heat exchanger, In the second lower limit temperature setting mode, the target temperature setting unit sets the target value based on a difference between the temperature detected by the forward temperature sensor and the temperature detected by the return temperature sensor, and sets a lower limit of the target value according to the temperature detected by the forward temperature sensor. Refrigeration cycle equipment.

10. The refrigeration cycle apparatus according to any one of claims 6 to 9, the heat source module is connected to a plurality of user-side units including both the direct expansion unit and the intermediate expansion unit, The target temperature setting unit sets, as the lower limit of the target value, the higher of the lower limit of the target value set in the first lower limit temperature setting mode and the lower limit of the target value set in the second lower limit temperature setting mode. Refrigeration cycle equipment.

11. a user side unit having a refrigerant heat exchanger that exchanges heat between a refrigerant and a heat exchange target; a heat source module having a compressor and a control device that controls the rotation speed of the compressor so that the temperature of the refrigerant flowing into the refrigerant heat exchanger becomes a target value; the control device has a target temperature setting unit that sets an upper limit of the target value when performing a cooling operation to cool the heat exchange target and a lower limit of the target value when performing a heating operation to heat the heat exchange target, The target temperature setting unit During cooling operation, when the user side unit that operates is a direct expansion unit, the upper limit of the target value is set in a first upper limit temperature setting mode, and when the user side unit that operates is a direct expansion unit, the upper limit of the target value is set in a second upper limit temperature setting mode that is different from the first upper limit temperature setting mode, During heating operation, when the user side unit that operates is a direct expansion unit, the lower limit of the target value is set in a first lower limit temperature setting mode, and when the user side unit that operates is a direct expansion unit, the lower limit of the target value is set in a second lower limit temperature setting mode that is different from the first lower limit temperature setting mode. Refrigeration cycle equipment.

12. The refrigeration cycle apparatus according to claim 11, the heat source module is connected to a plurality of user-side units including both the direct expansion unit and the intermediate expansion unit, The target temperature setting unit sets the upper limit of the target value to the lower of the upper limit of the target value set in the first upper limit temperature setting mode and the upper limit of the target value set in the second upper limit temperature setting mode. Refrigeration cycle equipment.

13. A heat source module is connected to a user side unit having a refrigerant heat exchanger that performs heat exchange between a refrigerant and a heat exchange target, and includes a compressor and a control device that controls the rotation speed of the compressor so that the temperature of the refrigerant flowing into the refrigerant heat exchanger becomes a target value, the control device has a target temperature setting unit that sets an upper limit of the target value when performing a cooling operation to cool the heat exchange target and a lower limit of the target value when performing a heating operation to heat the heat exchange target, The target temperature setting unit During cooling operation, when the user side unit that operates is a direct expansion unit, the upper limit of the target value is set in a first upper limit temperature setting mode, and when the user side unit that operates is a direct expansion unit, the upper limit of the target value is set in a second upper limit temperature setting mode that is different from the first upper limit temperature setting mode, During heating operation, when the user side unit that operates is a direct expansion unit, the lower limit of the target value is set in a first lower limit temperature setting mode, and when the user side unit that operates is a direct expansion unit, the lower limit of the target value is set in a second lower limit temperature setting mode that is different from the first lower limit temperature setting mode. Heat source module.

14. The heat source module according to claim 13, the user-side unit includes both the direct expansion unit and the intermediate expansion unit, The target temperature setting unit sets the upper limit of the target value to the lower of the upper limit of the target value set in the first upper limit temperature setting mode and the upper limit of the target value set in the second upper limit temperature setting mode. Heat source module.

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