Air conditioner, heat source module, indoor unit, and method for controlling air conditioner

Abstract

An air conditioner according to one embodiment of the present invention comprises: an outdoor unit which has a compressor and an outdoor heat exchanger; at least one relay unit which has a water-refrigerant heat exchanger for exchanging heat between a refrigerant and water and which is connected to the outdoor unit; a primary refrigerant circuit in which a primary refrigerant circulates; at least one indoor unit which is connected to the water-refrigerant heat exchanger and which has a water-heat exchanger; a circulation pump; a secondary refrigerant circuit in which a secondary refrigerant circulates; and a control device which controls the compressor. The control device executes either a room temperature control mode for controlling the rotation speed of the compressor on the basis of information on an indoor load or a water temperature control mode for controlling the rotation speed of the compressor on the basis of information on a heat load on the secondary refrigerant circuit.

Description

Air conditioner, heat source module, indoor unit, and air conditioner control method

[0001] The present invention relates to an air conditioner equipped with a relay unit that connects a refrigerant circuit and a water circuit, a heat source module, an indoor unit, and a method for controlling an air conditioner.

[0002] A known air conditioner includes a refrigerant circuit having a compressor for circulating a refrigerant and an outdoor heat exchanger, a water circuit having a water-refrigerant heat exchanger and a pump for circulating water that exchanges heat with the refrigerant, and a plurality of indoor units connected to the water circuit or the water circuit and the refrigerant circuit. A known method for this type of air conditioner is to control the compressor rotation speed based on the temperature difference between the room temperature and the set temperature during heating.

[0003] Japanese Patent Application Laid-Open No. 2003-65585

[0004] However, the technology described in Patent Document 1 assumes that an indoor unit equipped with a means for detecting an indoor load, such as a sensor for detecting an indoor temperature, is connected. Therefore, if an indoor unit not equipped with a means for detecting an indoor load is connected, or if a natural convection heating unit, such as a floor heating unit, is connected, the above control cannot be performed.

[0005] In view of the above circumstances, an object of the present invention is to provide an air conditioner, a heat source module, an indoor unit, and a control method for an air conditioner that can perform operation in accordance with the indoor load without relying on the function of the indoor unit.

[0006] An air conditioner according to one embodiment of the present invention comprises: an outdoor unit having a compressor and an outdoor heat exchanger; a primary refrigerant circuit including at least one relay unit connected to the outdoor unit and having a water-refrigerant heat exchanger that exchanges heat between a refrigerant and water, and through which a primary refrigerant circulates; at least one indoor unit connected to the water-refrigerant heat exchanger and having a water heat exchanger; and a secondary refrigerant circuit including a circulation pump and through which a secondary refrigerant circulates; and a control device that controls the compressor, wherein the control device executes either a room temperature control mode in which the rotation speed of the compressor is controlled based on information related to an indoor load, or a water temperature control mode in which the rotation speed of the compressor is controlled based on information related to the thermal load of the secondary refrigerant circuit.

[0007] The indoor unit may further have a room temperature sensor that detects the indoor temperature, and the control device may store a set temperature for the indoor temperature and calculate the indoor load based on the difference between the indoor temperature and the set temperature.

[0008] The secondary refrigerant circuit may further include a water temperature sensor located downstream of the water-refrigerant heat exchanger for detecting the temperature of the secondary refrigerant, and the control device may store a target temperature of the secondary refrigerant and calculate the thermal load based on the difference between the temperature of the secondary refrigerant and the target temperature.

[0009] The relay unit may further include a receiving unit that receives an input instruction from a user, and the control device may execute the water temperature control mode when the control device receives the input instruction via the receiving unit.

[0010] The secondary refrigerant circuit may have a plurality of indoor units, and the control device may execute the room temperature control mode by receiving information regarding the indoor load transmitted from the indoor units, and when there is one or more indoor units for which the transmission of information regarding the indoor load cannot be confirmed, may execute a water temperature control mode in which the rotation speed of the compressor is controlled based on information regarding the thermal load of the secondary refrigerant circuit.

[0011] A heat source module according to one embodiment of the present invention comprises: an outdoor unit having a compressor and an outdoor heat exchanger; a primary refrigerant circuit including at least one relay unit connected to the outdoor unit and having a water-refrigerant heat exchanger for exchanging heat between a refrigerant and water, through which a primary refrigerant circulates; and a control device for controlling the compressor, wherein the control device executes either a room temperature control mode in which the rotation speed of the compressor is controlled based on information regarding an indoor load transmitted from at least one indoor unit connected to the water-refrigerant heat exchanger and having a water heat exchanger, or a water temperature control mode in which the rotation speed of the compressor is controlled based on information regarding the thermal load of the secondary refrigerant circuit.

[0012] An indoor unit according to one embodiment of the present invention is an indoor unit having a water heat exchanger connected to the heat source module and connected to the water-refrigerant heat exchanger, and is equipped with an indoor load detection means for causing the control device to execute a room temperature control mode in which the rotation speed of the compressor is controlled based on information regarding the indoor load.

[0013] A control method for an air conditioner according to one embodiment of the present invention is a control method for an air conditioner equipped with: an outdoor unit having a compressor and an outdoor heat exchanger, a primary refrigerant circuit including at least one relay unit connected to the outdoor unit and having a water-refrigerant heat exchanger that exchanges heat between refrigerant and water, and through which a primary refrigerant circulates; at least one indoor unit connected to the water-refrigerant heat exchanger and having a water heat exchanger, and a secondary refrigerant circuit including a circulation pump and through which a secondary refrigerant circulates; when the outdoor unit receives information regarding an indoor load transmitted from the indoor unit, a room temperature control mode is executed in which the rotation speed of the compressor is controlled based on the information regarding the indoor load; and when transmission of information regarding the indoor load from the indoor unit cannot be confirmed, a water temperature control mode is executed in which the rotation speed of the compressor is controlled based on information regarding the thermal load of the secondary refrigerant circuit.

[0014] According to the present invention, operation that follows the indoor load can be performed without relying on the function of the indoor unit.

[0015] The present invention relates to an air conditioner having a refrigerant-water circuit, a control device for a compressor, and a control method for a refrigerant-water circuit.

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] <First embodiment> [Configuration of air conditioner] Fig. 1 is a refrigerant-water circuit diagram of an air conditioner 100 according to one embodiment of the present invention. The air conditioner 100 of this embodiment comprises an outdoor unit 2, a plurality of (three in this embodiment) indoor units 3a, 3b, and 3c (hereinafter collectively referred to as indoor units 3 unless individually described), a relay unit 50, and a control device 90. The outdoor unit 2 and the relay unit 50 form a heat source module 55 in the air conditioner 100.

[0018] (Outdoor Unit) The outdoor unit 2 has a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an expansion valve 24, and an accumulator 25. These devices and the relay unit 50 are interconnected by piping to form a refrigerant circuit 20 (primary refrigerant circuit) in the refrigerant-water circuit of the air conditioner 100. The relay unit 50 will be described later.

[0019] The compressor 21 is a variable displacement compressor whose operating capacity can be varied by controlling its rotation speed with an inverter (not shown). The refrigerant discharge side of the compressor 21 is connected to port a of the four-way valve 22 via a discharge pipe 61. The refrigerant suction side of the compressor 21 is connected to the refrigerant outlet side of the accumulator 25 via a suction pipe 65.

[0020] 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 via a discharge pipe 61. Port b is connected to one refrigerant inlet / outlet of the outdoor heat exchanger 23 via a refrigerant piping 62. Port c is connected to the refrigerant inlet / outlet side of the accumulator 25 via a refrigerant piping 66. Port d is connected to a gas refrigerant inlet / outlet 51b of a water-refrigerant heat exchanger 51 in the relay unit 50 (described later) via an outdoor unit gas pipe 64.

[0021] The outdoor heat exchanger 23 exchanges heat between the refrigerant and outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 29, which will be described later. One refrigerant inlet / outlet of the outdoor heat exchanger 23 is connected to port b of the four-way valve 22 by a refrigerant pipe 62, as described above, and the other refrigerant inlet / outlet is connected to a liquid refrigerant inlet / outlet 51 a of a water-refrigerant heat exchanger 51 in the relay unit 50, which will be described later, by an outdoor unit liquid pipe 63.

[0022] The expansion valve 24 is, for example, an electronic expansion valve. The 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.

[0023] The outdoor fan 29 is made of resin and is disposed near the outdoor heat exchanger 23. The outdoor fan 29 is driven by a fan motor (not shown), takes in outside air from an intake port (not shown) of the outdoor unit 2, exchanges heat with the refrigerant in the outdoor heat exchanger 23, and discharges the outside air from an outlet port (not shown) of the outdoor unit 2 to the outside of the outdoor unit 2.

[0024] (Indoor Unit) Each indoor unit 3 has an indoor heat exchanger 31, an indoor fan 32, and an on-off valve 33. Each indoor unit 3a to 3c has the same configuration, and by being connected to the relay unit 50, a water circuit 30 (secondary refrigerant circuit) is formed in the refrigerant-water circuit of the air conditioner 100. The water circuit 30 has a circulation pump 34 that circulates water as a secondary refrigerant between the relay unit and each indoor unit 3a to 3c.

[0025] The indoor heat exchanger 31 is a water heat exchanger that exchanges heat between water and outside air taken into the indoor unit 3 by the rotation of the indoor fan 32. The inlet side of the indoor heat exchanger 31 is connected to the water outlet 51d of the water-refrigerant heat exchanger 51 of the relay unit 50 by the first water pipe 11 and a first water branch pipe 111 branching from the first water pipe 11. The outlet side of the indoor heat exchanger 31 is connected to the water inlet 51c of the water-refrigerant heat exchanger 51 by the second water pipe 12 and a second water branch pipe 121 branching from the second water pipe 12. The circulation pump 34 is disposed in the second water pipe 12.

[0026] The indoor fan 32 is made of resin and is disposed 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 indoor unit 3, exchanges heat with water in the indoor heat exchanger 31, and blows the air into the room from an outlet (not shown) of the indoor unit 3. The indoor fan 32 and the indoor heat exchanger 31 constitute a fan coil unit (FCU).

[0027] The on-off valve 33 is disposed in the first water branch pipe 111 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 31. The opening and closing of the on-off valve 33 is controlled individually for each of the indoor units 3a to 3c, and the on-off valve 33 of an indoor unit 3 that is not operating (or is to be stopped) is switched to a closed state.

[0028] It should be noted that a flow control valve whose opening degree can be adjusted as desired may be used instead of the on-off valve 33. In this case, the flow rate of water flowing through the indoor heat exchanger 31 can be controlled according to the opening degree of the flow control valve. This allows the flow rate of water flowing into the indoor heat exchanger 31 to be adjusted for each indoor unit 3, improving the ability to follow the required capacity and increasing comfort.

[0029] (Relay Unit) The relay unit 50 has a water-refrigerant heat exchanger 51 and is connected to the outdoor unit 2. Note that, in this embodiment, as shown in Fig. 1 , the relay unit 50 is described as being installed outside the outdoor unit 2, but the relay unit 50 may also be installed inside the outdoor unit 2.

[0030] 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.

[0031] The refrigerant-side flow path 511 has one end connected to the liquid refrigerant inlet / outlet 51 a and the other end connected to the gas refrigerant inlet / outlet 51 b. The water-side flow path 512 has one end connected to the water inlet 51 c and the other end connected to the water outlet 51 d. 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.

[0032] The liquid refrigerant inlet / outlet 51a is connected to the other refrigerant inlet / outlet of the outdoor heat exchanger 23 by an outdoor unit liquid pipe 63. The gas refrigerant inlet / outlet 51b is connected to port d of the four-way valve 22 by an outdoor unit gas pipe 64. The water inlet 51c is connected to the indoor heat exchanger 31 of each indoor unit 3 by a second water pipe 12 and a second water branch pipe 121. The water outlet 51d is connected to the indoor heat exchanger 31 of each indoor unit 3 by a first water pipe 11 and a first water branch pipe 111.

[0033] The circulation pump 34 is a variable capacity pump driven by a motor (not shown). When the circulation pump 34 is driven, water flows out from the water outlet 51d of the water-refrigerant heat exchange unit 51 into the first water pipe 11, and circulates through the first water branch pipe 111, the indoor heat exchanger 31, the second water branch pipe 121, and the second water pipe 12 to flow into the water inlet 51c of the water-refrigerant heat exchange unit 51.

[0034] The relay unit 50 further includes a receiving unit 53 that receives input instructions from a user. The receiving unit 53 may be an input operation unit that accepts input instructions from a user, or a receiving device that receives an input signal corresponding to the input instructions generated by the input operation unit. The input instructions include, 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 30 (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.

[0035] The flow rate of water circulated by driving the circulation pump 34 is controlled by the rotation speed of the motor. This allows water to be supplied at the same flow rate to each indoor unit 3. In the example shown in Figure 1, the circulation pump 34 is disposed on the second water pipe 12, but instead, it may be disposed on the first water pipe 11, or may be disposed inside the relay unit 50.

[0036] (Sensors) Various sensors are provided in the air conditioner 100. In the outdoor unit 2, the discharge pipe 61 is provided with 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. The suction pipe 65 is provided with a low-pressure sensor 73 that detects the pressure of the refrigerant sucked into the compressor 21, and a suction temperature sensor 74 that detects the temperature of the refrigerant sucked into the compressor 21.

[0037] The outdoor heat exchanger 23 is provided with a heat exchanger 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.

[0038] The indoor unit 3 may be provided with a room temperature sensor 77 that detects the temperature of the air (room temperature) flowing into the indoor unit 3. The room temperature sensor 77 corresponds to a detection means for detecting the indoor load. The indoor load is calculated based on the difference between the temperature of the room in which the indoor unit 3 is installed (room temperature) and the set temperature of the indoor unit 3 (target room temperature). Note that the room temperature sensor 77 may be provided in only some of the indoor units 3a to 3c, or may not be provided in any of the indoor units 3a to 3c.

[0039] A first water temperature sensor 78 and a second water temperature sensor 79 are provided in the water circuit 30 downstream of the water-refrigerant heat exchanger 51. The first water temperature sensor 78 is provided in the first water pipe 11 connected to the water outlet 51d of the water-refrigerant heat exchanger 51, and detects the temperature of the water flowing out of the water-refrigerant heat exchanger 51. The second water temperature sensor 79 is provided in the second water pipe 12 connected to the water inlet 51c of the water-refrigerant heat exchanger 51, and detects the temperature of the water flowing into the water-refrigerant heat exchanger 51.

[0040] (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.

[0041] 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.

[0042] 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 status of the compressor 21, the outdoor fan 29, etc., the rotation speed of the indoor fan 32 obtained via the communication unit 93, the control status of each of the indoor units 3a to 3c including the operation mode input by the user, etc.

[0043] The communication unit 93 is an interface that communicates with the indoor unit 3 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.

[0044] 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.

[0045] The CPU 91 receives the detection results of the above-described sensors of the outdoor unit 2 via the sensor input unit 94. Furthermore, the CPU 91 receives control signals transmitted from the indoor unit 3 via the communication unit 93. The control signals transmitted from the indoor unit 3 include the required operating capacity required by the indoor unit 3 (the total indoor load of the indoor units 3a to 3c). Based on the received detection results and control signals, the CPU 91 controls the operation of the compressor 21, the outdoor fan 29, the indoor fan 32, and the circulation pump 34, for example, by setting the indicated rotation speeds at which these components are driven. Furthermore, the CPU 91 controls the switching of the four-way valve 22 based on the received detection results and control signals. Furthermore, the CPU 91 controls the opening degree of the expansion valve 24 and the opening and closing of the on-off valve 33 based on the received detection results and control signals.

[0046] 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 30. 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 in the indoor units 3a to 3c. Also, "thermal load" refers to a load calculated based on the detection results of various sensors in the water circuit 30.

[0047] [Basic Operation of Air Conditioner] Next, a description will be given of the basic operation of the air conditioner 100. Below, the operation of the air conditioner 100 during cooling operation and heating operation will be described.

[0048] (Cooling operation) When the air conditioner 100 performs cooling operation, 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 circulation pump 34 are driven. Driving the compressor 21 causes refrigerant to circulate through the refrigerant circuit 20, and driving the circulation pump 34 causes water to circulate through the water circuit 30. As a result, the outdoor heat exchanger 23 functions as a condenser, and the water-refrigerant heat exchanger 51 functions as an evaporator.

[0049] The rotation speed of the compressor 21 and the flow rate of the circulation pump 34 are determined according to information about the indoor load or information about the heat load of the water circuit 30. Here, an example will be described in which all of the indoor units 3 cool the rooms.

[0050] 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.

[0051] The refrigerant flowing out of the outdoor heat exchanger 23 flows through the outdoor unit liquid pipe 63 and is reduced in pressure when passing through the expansion valve 24. The opening degree of the expansion valve 24 is set 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 indoor unit 3 is installed, and more specifically, the opening degree is set so that the evaporation temperature in the water-refrigerant heat exchanger 51 and the temperature of the water flowing out of the water-refrigerant heat exchanger 51 are lower than the minimum value of the air conditioning temperature (set temperature) set in the indoor unit 3.

[0052] The refrigerant that passes through the expansion valve 24 and flows through the outdoor unit liquid pipe 63 flows into the liquid refrigerant inlet / outlet 51a of the water-refrigerant heat exchanger 51. 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, evaporating, and flows into the outdoor unit gas pipe 64 from the gas refrigerant inlet / outlet 51b of the water-refrigerant heat exchanger 51. 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 drawn into the compressor 21 and compressed again.

[0053] On the other hand, the water cooled while flowing through the water-side flow path 512 flows out from the water outlet 51d of the water-refrigerant heat exchanger 51 into the first water pipe 11, and the water that flows into the first water pipe 11 flows into the indoor heat exchanger 31 of each indoor unit 3 via the first water branch pipe 111 and the open on-off valve 33, and cools the indoor air passing through the indoor heat exchanger 31 by the rotation of the indoor fan 32. In this way, the room in which the indoor unit 3 is installed is cooled.

[0054] The water flowing out from the indoor heat exchanger 31 of each indoor unit 3 merges with the second water pipe 12 via the second water branch pipe 121 and is drawn into the circulation pump 34. The water drawn into the circulation pump 34 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 indoor unit 3.

[0055] (Heating operation) When the air conditioner 100 performs heating operation, 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 is connected to port d and port b is connected to port c, and the compressor 21 and circulation pump 34 are driven. Driving the compressor 21 causes refrigerant to circulate through the refrigerant circuit 20, and driving the circulation pump 34 causes water to circulate through the water circuit 30. As a result, the outdoor heat exchanger 23 functions as an evaporator, and the water-refrigerant heat exchanger 51 functions as a condenser.

[0056] The rotation speed of the compressor 21 and the flow rate of the circulation pump 34 are determined according to information about the indoor load or information about the heat load of the water circuit 30. Here, an example will be described in which all of the indoor units 3 heat the rooms.

[0057] 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. From the four-way valve 22, it flows into the outdoor unit gas pipe 64 and 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 outdoor unit liquid pipe 63.

[0058] The refrigerant flowing out into the outdoor unit liquid pipe 63 is decompressed when passing through the expansion valve 24. The opening degree of the expansion valve 24 is set so that the subcooling (degree of supercooling) of the refrigerant flowing out from the water-refrigerant heat exchanger 51 becomes a target subcooling to achieve the set temperature during heating operation in the room where the indoor unit 3 is installed, more specifically, so that the condensing temperature in the water-refrigerant heat exchanger 51 and the temperature of the water flowing out from the water-refrigerant heat exchanger 51 become higher than the maximum value of the air conditioning temperature (set temperature) set in the indoor unit 3.

[0059] The refrigerant that passes through the expansion valve 24 and flows through the outdoor unit liquid pipe 63 flows into the outdoor heat exchanger 23. The refrigerant that flows 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 flows out of the outdoor heat exchanger 23 flows through the refrigerant pipe 62, and is drawn into the compressor 21 via the four-way valve 22, the refrigerant pipe 66, the accumulator 25, and the suction pipe 65, where it is compressed again.

[0060] On the other hand, the water heated while flowing through the water-side flow path 512 flows out from the water outlet 51d of the water-refrigerant heat exchanger 51 into the first water pipe 11, and the water that has flowed into the first water pipe 11 flows into the indoor heat exchanger 31 via the first water branch pipe 111 and the open on-off valve 33, and heats the indoor air passing through the indoor heat exchanger 31 by the rotation of the indoor fan 32. This heats the room in which the indoor unit 3 is installed.

[0061] The water flowing out of the indoor heat exchanger 31 merges with the second water pipe 12 via the second water branch pipe 121 and is drawn into the circulation pump 34. The water drawn into the circulation pump 34 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 indoor unit 3.

[0062] [Details of the Control Device] As described above, the rotation speed of the compressor 21 and the flow rate of the circulation pump 34 are determined in accordance with information relating to the indoor load or information relating to the heat load of the water circuit 30 .

[0063] The information related to the indoor load includes the indoor temperature, which is the value detected by the room temperature sensor 77, and the set temperature (target value of the indoor temperature) of the indoor unit 3 equipped with the room temperature sensor 77. The indoor load is calculated based on the difference between the indoor temperature and the set temperature.

[0064] Meanwhile, the information relating to the thermal load of the water circuit 30 includes the water temperature detected by the first water temperature sensor 78 in the water circuit 30, the water temperature detected by the second water temperature sensor 79, 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 30 is calculated based on these water temperatures and input instruction values.

[0065] 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 regarding the indoor load, or a water temperature control mode in which the rotation speed of the compressor 21 is controlled based on information regarding the thermal load of the water circuit 30.

[0066] The indoor unit 3 connected to the heat source module 55 continuously transmits information relating to the indoor load to the control device 90 .

[0067] 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 indoor unit 3 that received the operation instruction. For example, if each indoor unit 3 that received the operation instruction is equipped with a room temperature sensor 77, the control device 90 will execute the room temperature control mode, thereby individually controlling the indoor space in which each indoor unit 3 is installed to the set temperature set for each indoor unit 3. On the other hand, if any one indoor unit 3 is not equipped with a room temperature sensor 77, the control device 90 will execute the water temperature control mode, thereby commonly controlling the indoor space in which each indoor unit 3 is installed to the set temperature corresponding to the input instruction from the user received by the receiving unit 53.

[0068] FIG. 3 is a flowchart showing an example of a procedure executed by the control device 90 to determine the control mode of the compressor 21 .

[0069] When the air conditioner 100 (heat source module 55) is started, the control device 90 identifies the indoor units 3 for which an operation command has been issued (ST101). The control device 90 then determines whether or not information relating to the indoor loads has been received from all of the indoor units 3 identified as having an operation command (ST102).

[0070] In this embodiment, the control device 90 executes the room temperature control mode when it receives information about the indoor load from all indoor units 3 that have been identified as having an operation instruction (Yes in ST102), and executes the water temperature control mode when it cannot confirm that it has received information about the indoor load from all indoor units 3 that have been identified as having an operation instruction (No in ST102).

[0071] In this embodiment, if a room temperature sensor 77 is provided in all indoor units 3 connected to the relay unit 50, or if a room temperature sensor 77 is provided in all indoor units 3 that will start operation, information regarding the indoor load transmitted from each indoor unit 3 can be received, and the room temperature control mode is executed based on the information regarding the indoor load transmitted from each indoor unit 3.

[0072] On the other hand, if at least one of the indoor units 3 connected to the relay unit 50 is not provided with a room temperature sensor 77, or if at least one of the indoor units 3 that will start operation is not provided with a room temperature sensor, the water temperature control mode is executed because reception of room information cannot be confirmed for all of these indoor units 3. In this case, the water temperature control mode is executed based on an input instruction received by the receiver 53 of the relay unit 50. Note that when the control device 90 receives an input instruction from the user via the receiver 53, the water temperature control mode may be executed even if the room temperature control mode is being executed.

[0073] In this way, even if all of the indoor units 3 connected to the relay unit 50 include an indoor unit that does not have a room temperature sensor 77, the room temperature control mode will be selected if all of the indoor units 3 that have been instructed to operate are equipped with a room temperature sensor 77. According to this embodiment, each time the air conditioner 100 starts operating, the control mode is determined based on whether or not information about the indoor load has been received from all of the indoor units 3 that have been instructed to operate, so an appropriate control mode can be automatically selected without considering whether or not the indoor units 3 connected to the relay unit 50 have a room temperature sensor 77. Furthermore, by repeatedly executing the determination process in ST102 at a predetermined cycle, even if an event occurs in which information about the indoor load cannot be transmitted due to a failure of the room temperature sensor 77 in some of the indoor units 3 while the room temperature control mode is being executed, switching from the room temperature control mode to the water temperature control mode can be automatically performed.

[0074] (Room temperature control mode) In the room temperature control mode, the controller 90 uses a pre-stored room temperature setting and calculates the room load based on the difference between the room temperature and the setting temperature (ST103).

[0075] The set temperature for the indoor temperature is input by the user via an operation panel (operation remote control) installed in each indoor unit 3. The indoor temperature is a value detected by a room temperature sensor 77 installed in each indoor unit 3. The input set temperature and detected indoor temperature are stored in the memory unit 92 of the control device 90 for each indoor unit 3. 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.

[0076] The control device 90 calculates the indoor load, which is the difference between the set temperature and the indoor temperature, for each indoor unit 3, and executes a room temperature control mode in which the rotation speed of the compressor 21 is controlled based on the total value of the indoor loads of these indoor units 3 (ST104).

[0077] While the room temperature control mode is being executed, the control device 90 controls the rotation speed of the compressor 21 in accordance with the operating capacity required by the indoor units 3 (the total value of the indoor loads of each indoor unit 3). Therefore, after all of the indoor units 3a to 3c have started operating, if, for example, indoor unit 3a stops operating due to thermo-off, the control device 90 controls the rotation speed of the compressor 21 in accordance with the indoor load resulting from the reduction in the number of operating indoor units 3. When determining the rotation speed of the compressor 21, a table or the like determined in advance in accordance with the magnitude of the indoor load may be referenced. Operation and stop of the indoor units 3 are switched by opening and closing the on-off valve 33 provided corresponding to each indoor unit 3.

[0078] (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 30, and calculates the thermal load of the water circuit 30 based on the difference between the water temperature of the water circuit 30 and the target temperature (ST105).

[0079] The target water temperature of the water circuit 30 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 30 is a detection value of the first water temperature sensor 78, 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 30 are stored in the memory 92 of the control device 90. The control device 90 periodically acquires the target temperature and the water temperature of the water circuit 30 and updates the target temperature and water temperature stored in the memory 92 to the latest target temperature and water temperature, respectively. The thermal load of the water circuit 30 may be calculated by estimating it based on the difference between the detection values ​​of the first water temperature sensor 78 and the second water temperature sensor 79. Specifically, the larger the difference, the higher the thermal load of the water circuit 30 is estimated to be.

[0080] The control device 90 calculates the thermal load of the water circuit 30 based on the difference between the water temperature of the water circuit 30 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 thermal load (ST106).

[0081] While the water temperature control mode is being executed, the control device 90 controls the rotation speed of the compressor 21 in accordance with the calculated heat load of the water circuit 30. Therefore, after all of the indoor units 3a to 3c have started operating, if, for example, indoor unit 3a stops operating due to thermo-off, the control device 90 controls the rotation speed of the compressor 21 in accordance with the heat load of the water circuit 30 that accompanies the reduction in the number of operating indoor units 3. When determining the rotation speed of the compressor 21, a table or the like that is determined in advance in accordance with the magnitude of the heat load of the water circuit 30 may be referenced. Operation and stop of the indoor units 3 are switched by opening and closing the on-off valve 33 provided corresponding to each indoor unit 3.

[0082] As described above, according to this embodiment, 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 related to the indoor load, or a water temperature control mode in which the rotation speed of the compressor 21 is controlled based on information related to the heat load of the water circuit 30, and therefore, the rotation speed of the compressor 21 can be appropriately controlled according to the specifications or model of the indoor unit 3 connected to the relay unit 50. Furthermore, even when indoor units equipped with room temperature sensors 77 and indoor units not equipped with room temperature sensors 77 are mixed, the indoor spaces in which each indoor unit is installed can be controlled to the desired air-conditioning temperature.

[0083] 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.

[0084] For example, in the above embodiment, the number of relay units 50 connected to the outdoor unit 2 is one, but it may be two or more. Also, the number of indoor units 3 connected to the relay unit is three, but this is not limited to this, and it is sufficient that at least one indoor unit is connected.

[0085] Furthermore, in the above embodiment, an air conditioner equipped with an indoor unit 3 (first indoor unit) equipped with a water heat exchanger as an indoor heat exchanger has been described as an example, but this is not limited to this, and the present invention can also be applied to an air conditioner that, in addition to the indoor unit 3, further includes an indoor unit (second indoor unit) equipped with a refrigerant heat exchanger through which refrigerant flowing in and out of the primary refrigerant circuit 10 flows.

[0086] DESCRIPTION OF SYMBOLS 2...Outdoor unit 3 (3a, 3b, 3c)...Indoor unit 20...Primary refrigerant circuit 21...Compressor 22...Four-way valve 23...Outdoor heat exchanger 24...Expansion valve 30...Water circuit (secondary refrigerant circuit) 31...Indoor heat exchanger 32...Indoor fan 34...Circulation pump 33...Open / close valve 50...Relay unit 51...Water-refrigerant heat exchanger 53...Receiver 55...Heat source module 78...First water temperature sensor 79...Second water temperature sensor 90...Control device 100...Air conditioner

Claims

1. An air conditioner comprising: an outdoor unit having a compressor and an outdoor heat exchanger, at least one relay unit having a water-refrigerant heat exchanger that exchanges heat between a refrigerant and water and connected to the outdoor unit, a primary refrigerant circuit through which a primary refrigerant circulates, at least one indoor unit connected to the water-refrigerant heat exchanger and having a water heat exchanger, and a secondary refrigerant circuit including a circulating pump and through which a secondary refrigerant circulates, and a control device that controls the compressor, wherein the control device executes either a room temperature control mode that controls the rotation speed of the compressor based on information related to an indoor load, or a water temperature control mode that controls the rotation speed of the compressor based on information related to the thermal load of the secondary refrigerant circuit.

2. An air conditioner as claimed in claim 1, wherein the indoor unit further comprises a room temperature sensor for detecting an indoor temperature, and the control device stores a set temperature for the indoor temperature, and calculates the indoor load based on the difference between the indoor temperature and the set temperature.

3. An air conditioner as described in claim 1, wherein the secondary refrigerant circuit further includes a water temperature sensor provided downstream of the water-refrigerant heat exchanger for detecting the temperature of the secondary refrigerant, and the control device stores a target temperature of the secondary refrigerant and calculates the thermal load based on the difference between the temperature of the secondary refrigerant and the target temperature.

4. An air conditioner as claimed in claim 1, wherein the relay unit further has a receiving unit for receiving an input instruction from a user, and the control device executes the water temperature control mode when the control device receives the input instruction via the receiving unit.

5. An air conditioner as described in claim 1, wherein the secondary refrigerant circuit has a plurality of indoor units, and the control device executes the room temperature control mode by receiving information relating to the indoor load transmitted from the indoor units, and when there is one or more indoor units for which the transmission of information relating to the indoor load cannot be confirmed, executes a water temperature control mode in which the rotation speed of the compressor is controlled based on information relating to the thermal load of the secondary refrigerant circuit.

6. A heat source module comprising: an outdoor unit having a compressor and an outdoor heat exchanger; at least one relay unit having a water-refrigerant heat exchanger for exchanging heat between a refrigerant and water and connected to the outdoor unit, a primary refrigerant circuit through which a primary refrigerant circulates; and a control device for controlling the compressor, wherein the control device executes either a room temperature control mode in which the rotation speed of the compressor is controlled based on information regarding an indoor load transmitted from at least one indoor unit having a water heat exchanger and connected to the water-refrigerant heat exchanger, or a water temperature control mode in which the rotation speed of the compressor is controlled based on information regarding the thermal load of the secondary refrigerant circuit.

7. An indoor unit connected to the heat source module according to claim 6 and having a water heat exchanger connected to the water-refrigerant heat exchanger, the indoor unit being provided with a means for detecting the indoor load, for causing the control device to execute a room temperature control mode in which the number of revolutions of the compressor is controlled based on information regarding the indoor load.

8. A control method for an air conditioner equipped with an outdoor unit having a compressor and an outdoor heat exchanger, at least one relay unit having a water-refrigerant heat exchanger for exchanging heat between refrigerant and water and connected to the outdoor unit, a primary refrigerant circuit through which a primary refrigerant circulates, at least one indoor unit having a water heat exchanger connected to the water-refrigerant heat exchanger, and a secondary refrigerant circuit including a circulating pump and through which a secondary refrigerant circulates, wherein, when the outdoor unit receives information regarding an indoor load transmitted from the indoor unit, a room temperature control mode is executed in which the rotation speed of the compressor is controlled based on the information regarding the indoor load, and when the transmission of information regarding the indoor load from the indoor unit cannot be confirmed, a water temperature control mode is executed in which the rotation speed of the compressor is controlled based on information regarding the thermal load of the secondary refrigerant circuit.

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