WO2024252468A1 - Refrigeration cycle device - Google Patents

Abstract

This refrigeration cycle device comprises: a compressor that compresses a refrigerant; a heat source machine that has a heat source-side heat exchanger for performing heat exchange between the refrigerant and outdoor air and a heat source-side blower for supplying the outdoor air to the heat source-side heat exchanger; a load device that has a load-side heat exchanger for performing heat exchange between the refrigerant and a fluid to be heated or cooled; an auxiliary heat source machine that has a heating medium heat exchanger for performing heat exchange between the refrigerant and a heating medium which differs from the outdoor air and which has heat derived from renewable energy; and a control device that, on the basis of the result of a comparison between the temperature of the heating medium and the temperature of the outdoor air, controls the rotational speed of the heat source-side blower to a rotational speed within a first range that is a range of rotational speeds lower than the rotational speed during a rated operation.

Description

Refrigeration Cycle Equipment

This disclosure relates to a refrigeration cycle device.

　Conventionally, it has been proposed to utilize so-called renewable energy such as geothermal heat in refrigeration cycle devices such as air conditioners (for example, Patent Document 1). The air conditioner of Patent Document 1 has a heat exchanger for exchanging heat between the heat source having renewable energy and the refrigerant in addition to the heat exchanger of the heat source unit, thereby increasing the total heat transfer area. In this way, the air conditioner of Patent Document 1 aims to improve the air conditioning capacity.

JP 2017-203573 A

However, in Patent Document 1, even though the total heat transfer area has increased, some of the equipment is controlled in the same way as if there were no heat source with renewable energy. Therefore, the air conditioner in Patent Document 1 is operated at a capacity higher than necessary, resulting in unnecessary consumption of electricity.

This disclosure has been made to solve the problems described above, and aims to provide a refrigeration cycle device that improves energy-saving performance.

The refrigeration cycle device according to the present disclosure includes a heat source unit having a compressor that compresses a refrigerant, a heat source side heat exchanger that exchanges heat between the refrigerant and outdoor air, and a heat source side blower that supplies outdoor air to the heat source side heat exchanger; a load unit having a load side heat exchanger that exchanges heat between the refrigerant and a fluid that is to be heated or cooled; an auxiliary heat source unit having a heat medium heat exchanger that exchanges heat between the refrigerant and a heat medium that has heat derived from a renewable energy different from the outdoor air; and a control device that controls the rotation speed of the heat source side blower to within a first range that is a range of rotation speeds lower than the rotation speed during rated operation based on the comparison result between the temperature of the heat medium and the temperature of the outdoor air.

According to the refrigeration cycle device disclosed herein, the rotation speed of the heat source side blower is controlled to within a first range, which is a range of rotation speeds lower than the rotation speed during rated operation. Therefore, the refrigeration cycle device can reduce the power consumption related to the operation of the heat source side blower and improve energy saving performance.

2 is a refrigerant circuit diagram showing a flow of refrigerant during cooling operation of the refrigeration cycle device according to the first embodiment. FIG. FIG. 2 is a hardware configuration diagram showing a control device according to the first embodiment. FIG. 2 is a hardware configuration diagram showing a control device according to the first embodiment. 1 is a functional block diagram showing a refrigeration cycle device according to a first embodiment. FIG. 2 is a refrigerant circuit diagram showing a flow of a refrigerant during heating operation of the refrigeration cycle device according to the first embodiment. FIG. 5 is a flowchart showing a method for controlling the rotation speed of the heat source side blower according to the first embodiment. FIG. 11 is a refrigerant circuit diagram showing a flow of a refrigerant during heating operation of a refrigeration cycle device according to a second embodiment. FIG. 11 is a functional block diagram showing a refrigeration cycle device according to a second embodiment. FIG. 11 is a refrigerant circuit diagram showing a flow of refrigerant during cooling operation of a refrigeration cycle device according to a third embodiment. FIG. 11 is a functional block diagram showing a refrigeration cycle device according to a third embodiment. FIG. 11 is a refrigerant circuit diagram showing a flow of a refrigerant during heating operation of a refrigeration cycle device according to a third embodiment. FIG. 11 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle device according to a fourth embodiment. FIG. 13 is a functional block diagram showing a refrigeration cycle device according to a fourth embodiment. FIG. 11 is a refrigerant circuit diagram showing a flow of a refrigerant during heating operation of a refrigeration cycle device according to a fourth embodiment. FIG. 11 is a refrigerant circuit diagram showing a flow of a refrigerant during heating operation of a refrigeration cycle device according to a fourth embodiment. FIG. 11 is a refrigerant circuit diagram showing a refrigeration cycle device according to a modified example.

Below, an embodiment will be described with reference to the drawings. In each drawing, the same reference numerals are used to denote the same or equivalent parts, and this is the same throughout the entire specification. Furthermore, the forms of the components shown in the entire specification are merely examples and are not limited to these descriptions. Furthermore, the size relationships between the components in the drawings may differ from the actual ones.

Embodiment 1.
FIG. 1 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus 1 according to embodiment 1. The refrigeration cycle apparatus 1 of embodiment 1 is an air conditioner that cools and heats a room. The refrigeration cycle apparatus 1 includes a heat source unit 2, load devices 3a and 3b, and an auxiliary heat source unit 4. The heat source unit 2 and the load devices 3a and 3b are connected by a first connection pipe 401. The load devices 3a and 3b are connected by a second connection pipe 402, and the auxiliary heat source unit 4 and the heat source unit 2 are connected by a third connection pipe 403.

In the following, an example will be described in which the refrigeration cycle device 1 is an air conditioner capable of performing at least cooling operation and heating operation as operating modes, but the refrigeration cycle device 1 may also be a refrigerator, freezer, or vending machine that cools stored items. The refrigeration cycle device 1 may also be a refrigeration device installed in a showcase or the like. Furthermore, the refrigeration cycle device 1 may also be a water heater that supplies hot water, or a chiller that supplies cold water. The refrigeration cycle device 1 may also be capable of performing operating modes other than cooling operation and heating operation, such as dehumidification operation.

The heat source unit 2 is, for example, an outdoor unit installed outdoors. The heat source unit 2 is a device that supplies hot or cold heat to the load device 3. The heat source unit 2 has a compressor 21, a flow path switching device 22, a heat source side heat exchanger 23, a heat source side blower 24, a heat source side throttle device 25, an accumulator 26, and a control device 100.

The compressor 21 draws in low-pressure gas refrigerant, compresses it, and discharges it as high-pressure gas refrigerant. As the compressor 21, for example, a reciprocating, rotary, scroll, or screw compressor 21 is used.

The flow path switching device 22 switches between cooling operation, in which the heat source side heat exchanger 23 functions as a condenser, and heating operation, in which the heat source side heat exchanger 23 functions as an evaporator. The flow path switching device 22 is, for example, a four-way valve, and is controlled by the control device 100. During cooling operation, the flow path switching device 22 is switched so that the refrigerant discharged from the compressor 21 flows into the heat source side heat exchanger 23. During heating operation, the flow path switching device 22 is switched so that the refrigerant discharged from the compressor 21 flows into the load devices 3a and 3b.

The heat source side heat exchanger 23 is, for example, a fin tube type heat exchanger, and exchanges heat between the refrigerant flowing inside the circular or flat tubes and the outdoor air supplied by the heat source side blower 24. The heat source side heat exchanger 23 functions as an evaporator during heating operation and as a condenser during cooling operation.

The heat source side blower 24 is a device that sends outdoor air to the heat source side heat exchanger 23. The heat source side blower 24 is disposed adjacent to the heat source side heat exchanger 23. By sending outdoor air from the heat source side blower 24, the efficiency of heat exchange between the refrigerant and the outdoor air is improved. As the heat source side blower 24, a propeller fan, a line flow fan (registered trademark), or a multi-blade centrifugal fan is used.

The heat source side throttle device 25 is an electronic expansion valve with an adjustable opening. The heat source side throttle device 25 reduces the pressure of the refrigerant flowing into the heat source side heat exchanger 23 or the refrigerant flowing out from the heat source side heat exchanger 23, causing it to expand. The opening of the heat source side throttle device 25 is controlled by the control device 100.

The accumulator 26 stores excess refrigerant depending on the operating state. The accumulator 26 is connected to the intake port of the compressor 21 and the flow path switching device 22, and separates the refrigerant that flows in through the flow path switching device 22 into gas refrigerant and liquid refrigerant, stores the liquid refrigerant, and allows the gas refrigerant to flow to the compressor 21. Note that the accumulator 26 is not a required component and may be omitted.

The control device 100 controls each device of the refrigeration cycle device 1. FIG. 2 is a hardware configuration diagram showing the control device 100 according to the first embodiment. As shown in FIG. 2, the control device 100 is dedicated hardware configured with a processing circuit 101 such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). FIG. 3 is a hardware configuration diagram showing the control device 100 according to the first embodiment. When the functions of the control device 100 are performed by software, the control device 100 may be configured with a processor 102 such as a CPU and a memory 103 as shown in FIG. 3. FIG. 3 shows that the processor 102 and the memory 103 are connected to each other so as to be able to communicate with each other via a bus 104. The functions of the control device 100 are realized by the processor 102 reading and executing a program stored in the memory 103. The memory 103 may be a non-volatile or volatile semiconductor memory, or a removable recording medium. The functions of the control device 100 will be described later.

In FIG. 1, the control device 100 is provided in the heat source device 2, but the control device 100 may be provided in the load device 3a or 3b, or the heat source device 2 and the load devices 3a and 3b may each be provided with a separate control device 100 that communicates with each other. The control device 100 may also be provided in a location away from the heat source device 2 and the load device 3.

The load devices 3a and 3b are, for example, indoor units installed in a room. The load devices 3a and 3b receive cold or hot heat via refrigerant from the heat source device 2 and the auxiliary heat source device 4 to air-condition the room. The load device 3a has a load side heat exchanger 31a, a load side blower 32, and a load side throttling device 33a. The load device 3b has a load side heat exchanger 31b, a load side blower 32, and a load side throttling device 33b. In the following, when there is no need to distinguish between the load devices 3a and 3b and the devices that the load devices 3a and 3b have, the suffixes "a" and "b" will be omitted in the description.

The load side heat exchanger 31 is, for example, a fin tube type heat exchanger, and exchanges heat between the refrigerant flowing inside the circular or flat tubes and the indoor air supplied by the load side blower 32. The load side heat exchanger 31 functions as a condenser during heating operation, and as an evaporator during cooling operation. If the refrigeration cycle device 1 is, for example, a chiller, the load side heat exchanger 31 may exchange heat between the refrigerant and water to supply cold water. If the refrigeration cycle device 1 is, for example, a water heater, the load side heat exchanger 31 may exchange heat between the refrigerant and water to supply hot water. The fluid that exchanges heat with the refrigerant in the load side heat exchanger 31 corresponds to the "fluid" in this disclosure.

When the refrigeration cycle device 1, which is an air conditioner, performs cooling operation, the air in the air-conditioned space in which the load device 3 is installed is the "cooling target" of this disclosure. Also, when the refrigeration cycle device 1, which is a chiller, supplies cold water, the water flowing through the load side heat exchanger 31 is the "cooling target" of this disclosure. Similarly, when the refrigeration cycle device 1, which is an air conditioner, performs heating operation, the air in the air-conditioned space in which the load device 3 is installed is the "heating target" of this disclosure. Also, when the refrigeration cycle device 1, which is a water heater, supplies hot water, the water flowing through the load side heat exchanger 31 is the "heating target" of this disclosure.

The load side blower 32 is a device that sends indoor air to the load side heat exchanger 31. The load side blower 32 is disposed adjacent to the load side heat exchanger 31. By sending indoor air from the load side blower 32, the efficiency of heat exchange between the refrigerant and the indoor air is improved. As the load side blower 32, a propeller fan, a line flow fan (registered trademark), or a multi-blade centrifugal fan is used. Note that, if the load side heat exchanger 31 exchanges heat between a fluid such as water and a refrigerant, a pump that circulates water or the like may be used instead of the load side blower 32.

The load side throttle device 33 is an electronic expansion valve whose opening is adjustable. The load side throttle device 33 reduces the pressure of the refrigerant flowing into the load side heat exchanger 31 or the refrigerant flowing out from the load side heat exchanger 31, causing it to expand. The opening of the load side throttle device 33 is controlled by the control device 100.

The auxiliary heat source unit 4 is a device that supplies hot or cold heat to the load device 3. As will be described in detail later, the auxiliary heat source unit 4 uses renewable energy as a heat source and performs an auxiliary function to the heat source unit 2. The auxiliary heat source unit 4 has a heat medium heat exchanger 41, an auxiliary side throttle device 42, and a pump 43.

The heat medium heat exchanger 41 is, for example, a plate-type heat exchanger, and performs heat exchange between the refrigerant and the heat medium. The heat medium heat exchanger 41 has a refrigerant flow path (not shown) through which the refrigerant flows, and a heat medium flow path (not shown) through which the heat medium flows. The compressor 21, flow path switching device 22, heat source side heat exchanger 23, and heat source side throttling device 25 of the heat source unit 2, the load side heat exchanger 31 and load side throttling device 33 of the load unit 3, and the refrigerant flow path and auxiliary side throttling device 42 of the heat medium heat exchanger 41 of the auxiliary heat source unit 4 are connected by a first connection pipe 401, a second connection pipe 402, and a third connection pipe 403 to form a refrigerant circuit.

The refrigerant used is a fluid that undergoes latent heat change. For example, a single refrigerant selected from R1234yf, R1234ze, R32, or R290, a mixed refrigerant made by mixing two or more of these, or a mixed refrigerant made by mixing one of these with another refrigerant, is used.

The heat medium flow path of the heat medium heat exchanger 41 is connected to a tank 52 in which the heat medium is stored by a heat medium pipe 601. The heat medium is supplied to the heat medium flow path from the tank 52 via the heat medium pipe 601. A water circuit is formed by connecting the tank 52 and the heat medium flow path of the heat medium heat exchanger 41 by the heat medium pipe 601. The heat medium pipe 601 is provided with a pump 43 that circulates the heat medium in the water circuit. The pump 43 is, for example, an inverter-type centrifugal pump whose capacity can be controlled.

It is desirable that the temperature of the heat medium circulating through the water circuit be stable throughout the year. In particular, it is desirable that the heat medium be at a lower temperature than the outdoor air during cooling operation, and at a higher temperature than the outdoor air during heating operation. The heat medium heat exchanger 41 acts as a condenser during cooling operation, exchanging heat between the refrigerant flowing through the refrigerant flow path and the heat medium flowing through the heat medium flow path, condensing and liquefying the refrigerant. The heat medium heat exchanger 41 acts as an evaporator during heating operation, exchanging heat between the refrigerant that has flowed inside and the heat medium, evaporating and vaporizing the refrigerant.

The heat medium stored in the tank 52 is, for example, well water. Well water contains geothermal heat, which is a renewable energy contained in the earth. In other words, well water is a fluid that contains heat derived from geothermal heat, and the heat medium heat exchanger 41 uses the geothermal heat contained in the well water as a heat source. Note that renewable energy means energy that is naturally replenished at a rate faster than it can be used.

Solar heat may be used as the heat source used by the heat medium heat exchanger 41. When solar heat is used as the heat source of the heat medium heat exchanger 41, the heat medium warmed by a solar panel or the like is stored in the tank 52. In this case, a specific heat medium is a fluid that undergoes latent heat change, such as a calcium chloride solution, a sodium chloride solution, a magnesium chloride solution, a brine containing ethylene glycol, an antifreeze, or water. However, instead of directly circulating well water through the heat medium heat exchanger 41, a heat exchanger that exchanges heat between the heat medium, such as a calcium chloride solution, a sodium chloride solution, a magnesium chloride solution, a brine containing ethylene glycol, an antifreeze, or water, and the well water may be provided in the tank 52, and the heat medium that has been exchanged may be circulated through the water circuit. In addition, a fluid having heat derived from renewable energy other than geothermal heat and solar heat may be used as the fluid flowing through the heat medium heat exchanger 41 described above.

The refrigeration cycle device 1 has a first bypass pipe 501 and a first bypass valve 51. The first bypass pipe 501 is a pipe that connects the second connection pipe 402 and the third connection pipe 403. The first bypass valve 51 is a valve provided in the first bypass pipe 501. The first bypass valve 51 is a valve that can be selectively switched between an open state that allows the flow of refrigerant through the first bypass pipe 501 and a closed state that blocks the flow of refrigerant through the first bypass pipe 501.

The refrigeration cycle device 1 has an outdoor air temperature sensor 27, indoor temperature sensors 34a and 34b, a first heat medium temperature sensor 44, and a second heat medium temperature sensor 45. The outdoor air temperature sensor 27 is provided in the heat source unit 2. The outdoor air temperature sensor 27 is, for example, a thermistor, and measures the temperature of the air outside the room where the heat source unit 2 is provided. The indoor air temperature sensor 34 is provided in the load device 3. The indoor air temperature sensor 34 is, for example, a thermistor, and is a sensor that measures the temperature of the air in the room where the load device 3 is provided.

The first heat medium temperature sensor 44 is provided on the heat medium pipe 601 upstream of the heat medium heat exchanger 41. The first heat medium temperature sensor 44 is, for example, a thermistor, and measures the temperature of the heat medium flowing into the heat medium heat exchanger 41. The second heat medium temperature sensor 45 is provided on the heat medium pipe 601 downstream of the heat medium heat exchanger 41. The second heat medium temperature sensor 45 is, for example, a thermistor, and measures the temperature of the heat medium flowing into the heat medium heat exchanger 41. In the following description, when simply referred to as "heat medium temperature," it refers to the temperature of the heat medium flowing upstream of the heat medium heat exchanger 41. The outdoor air temperature sensor 27, the indoor temperature sensors 34a and 34b, the first heat medium temperature sensor 44, and the second heat medium temperature sensor 45 transmit the measurement results to the control device 100 connected by wire or wirelessly.

The refrigeration cycle device 1 may also be equipped with temperature sensors or pressure sensors other than the outdoor air temperature sensor 27, the indoor temperature sensors 34a and 34b, the first heat medium temperature sensor 44, and the second heat medium temperature sensor 45. For example, the refrigeration cycle device 1 may be equipped with a sensor that detects either the temperature of the refrigerant flowing through the heat source side heat exchanger 23 or the load side heat exchanger 31, or the temperature of the air blown out from the outlet of the load device 3.

FIG. 4 is a functional block diagram showing the refrigeration cycle device 1 according to the first embodiment. As shown in FIG. 4, the control device 100 is connected to the compressor 21, the flow path switching device 22, the heat source side blower 24, the heat source side throttle device 25, the load side blower 32, the load side throttle device 33, the first bypass valve 51, the auxiliary side throttle device 42, and the pump 43 so that they can communicate wirelessly or by wire. The control device 100 controls the connection direction of the flow path switching device 22 to switch the operation mode. The control device 100 controls the rotation speed of the compressor 21, the rotation speed of the heat source side blower 24, the opening degree of the heat source side throttle device 25, the rotation speed of the load side blower 32, the opening degree of the load side throttle device 33, the opening degree of the auxiliary side throttle device 42, and the rotation speed of the pump 43 so that the temperature of the indoor air measured by the indoor air temperature sensor 34 becomes the temperature set by the user.

The control device 100 also controls the opening of the auxiliary side throttling device 42 during heating operation so that the refrigerant flowing out of the heat medium heat exchanger 41 becomes a superheated gas. The control device 100 controls the opening of the auxiliary side throttling device 42 so that the measurement results of a temperature sensor (not shown) and a pressure sensor (not shown) provided on the outflow side of the heat medium heat exchanger 41 reach target values, for example. This ensures that the refrigerant drawn into the compressor 21 is in a gas state.

When the heat medium temperature measured by the first heat medium temperature sensor 44 is equal to or higher than the threshold temperature, the control device 100 controls the pump 43 so that the heat medium circulation amount becomes a first flow rate. When the heat medium temperature is lower than the threshold temperature, the control device 100 controls the pump 43 so that the heat medium circulation amount becomes a second flow rate that is greater than the first flow rate. The threshold temperature is the temperature at which the heat medium freezes, and is, for example, 0°C. In this way, when the heat medium is lower than the threshold temperature, the heat medium can be prevented from freezing by increasing the heat medium circulation amount. Note that the heat medium temperature compared with the threshold temperature here may not be the temperature measured by the first heat medium temperature sensor 44, but may be the temperature of the heat medium flowing downstream of the heat medium heat exchanger 41 measured by the second heat medium temperature sensor 45. It may also be the average value of the temperatures of the heat medium flowing upstream and downstream of the heat medium heat exchanger 41.

In particular, the control device 100 limits the range of the rotation speed of the heat source side blower 24 based on the comparison result between the heat medium temperature and the outdoor air temperature. Specifically, when the heat medium temperature is lower than the outdoor air temperature during cooling operation, the control device 100 controls the rotation speed of the heat source side blower 24 to within a first range. Similarly, when the heat medium temperature is higher than the outdoor air temperature during heating operation, the control device 100 controls the rotation speed of the heat source side blower 24 to within the first range. The first range is a range of rotation speeds lower than the rotation speed during rated operation. The rotation speed during rated operation is the maximum rotation speed at which the heat source side blower 24 can operate. The maximum rotation speed within the first range is, for example, 70% of the rotation speed during rated operation. The first range also includes the case where the rotation speed is 0, and when the rotation speed of the heat source side blower 24 is controlled to a rotation speed within the first range, the heat source side blower 24 may stop.

In other words, when the heat medium temperature is lower than the outdoor air temperature during cooling operation, the control device 100 limits the rotation speed of the heat source side blower 24 to a speed lower than the maximum rotation speed, and adjusts it to the minimum rotation speed at which the indoor air temperature can reach the set temperature. In other words, the control device 100 limits the rotation speed of the heat source side blower 24 to a speed lower than the maximum rotation speed, and adjusts it to the minimum rotation speed at which the heat exchange amount in the heat source side heat exchanger 23 and the heat medium heat exchanger 41 and the indoor load are balanced. The same applies when the heat medium temperature is higher than the outdoor air temperature during heating operation.

The control device 100 may stop the heat source side blower 24 if the amount of heat exchange in the heat medium heat exchanger 41 is balanced with the indoor load without heat exchange by the heat source side heat exchanger 23. For example, when the rotation speed of the heat source side blower 24 is at a minimum, the control device 100 may stop the heat source side blower 24 if it determines that the amount of heat exchange in the heat source side heat exchanger 23 and the heat medium heat exchanger 41 is excessive compared to the indoor load.

However, the control device 100 may block the flow of refrigerant to the heat medium heat exchanger 41 when it is determined that the heat medium heat exchanger 41 does not function effectively as a condenser in cooling operation or as an evaporator in heating operation. Specifically, the control device determines that the heat medium heat exchanger does not function effectively as a condenser when the heat medium temperature is equal to or higher than the temperature of the outdoor air during cooling operation. Similarly, the control device determines that the heat medium heat exchanger does not function effectively as an evaporator when the heat medium temperature is equal to or lower than the temperature of the outdoor air during heating operation. In addition, the control device 100 blocks the flow of refrigerant to the heat medium heat exchanger 41 by opening the first bypass valve 51 and closing the auxiliary side throttling device 42. In this case, the refrigeration cycle device 1 functions in the same way as a refrigeration cycle device without an auxiliary heat source unit 4, so the control device 100 controls the rotation speed of the heat source side blower 24 in the same way as a refrigeration cycle device without an auxiliary heat source unit 4. In other words, the control device 100 controls the rotation speed of the heat source side blower 24 to within a second range, which is a range of rotation speeds that includes the rotation speed during rated operation.

The operation and flow of the refrigerant when the refrigeration cycle device 1 uses the auxiliary heat source unit 4 will be described. First, the cooling operation will be described with reference to FIG. 1. The control device 100 performs cooling operation by switching the flow path switching device 22 so that the discharge side of the compressor 21 and the heat source side heat exchanger 23 are connected. At this time, the refrigerant sucked into the compressor 21 is compressed and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas state refrigerant discharged from the compressor 21 passes through the flow path switching device 22 and flows into the heat source side heat exchanger 23 acting as a condenser. The refrigerant that flows into the heat source side heat exchanger 23 is heat exchanged with the outdoor air sent by the heat source side blower 24 and condensed, becoming a high-temperature, high-pressure gas-liquid two-phase state. The high-temperature, high-pressure gas-liquid two-phase refrigerant flows into the heat medium heat exchanger 41 acting as a condenser. The refrigerant that flows into the heat medium heat exchanger 41 is heat exchanged with the heat medium and condensed, becoming a high-pressure liquid state.

The high-pressure liquid refrigerant flows into the load-side throttle device 33, where it is decompressed and expanded to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant flows into the load-side heat exchanger 31, which acts as an evaporator. The refrigerant that flows into the load-side heat exchanger 31 exchanges heat with the indoor air sent by the load-side blower 32, causing the liquid phase to evaporate and become a gas. At that time, the indoor air is cooled and cooling is performed in the room. The low-temperature, low-pressure gas refrigerant that flows out of the load-side heat exchanger 31 passes through the flow switching device 22 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. This cycle is repeated during the cooling operation of the refrigeration cycle device 1.

Next, the heating operation will be described with reference to FIG. 5. FIG. 5 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the refrigeration cycle device 1 according to the first embodiment. The control device 100 performs heating operation by switching the flow path switching device 22 so that the suction side of the compressor 21 and the heat source side heat exchanger 23 are connected. At this time, the refrigerant sucked into the compressor 21 is compressed and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas state refrigerant discharged from the compressor 21 passes through the flow path switching device 22 and flows into the load side heat exchanger 31 acting as a condenser. The refrigerant that flows into the load side heat exchanger 31 exchanges heat with the indoor air sent by the load side blower 32, condenses, and becomes a low-temperature liquid state. At this time, the indoor air is warmed, and heating is performed in the room.

The low-temperature, high-pressure liquid refrigerant is decompressed by the load-side throttle device 33 and the auxiliary-side throttle device 42 to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The low-temperature, low-pressure, two-phase gas-liquid refrigerant flows into the heat medium heat exchanger 41, which acts as an evaporator. The low-temperature, low-pressure, two-phase gas-liquid refrigerant that flows into the heat medium heat exchanger 41 exchanges heat with the heat medium, evaporating the liquid phase and becoming a superheated gas state. The superheated gas refrigerant that flows out of the heat medium heat exchanger 41 flows into the heat source-side heat exchanger 23, which acts as an evaporator. The superheated gas refrigerant that flows into the heat source-side heat exchanger 23 exchanges heat with the outdoor air supplied by the heat source-side blower 24, increasing the degree of superheat. The superheated gas refrigerant that flows out of the heat source-side heat exchanger 23 passes through the flow switching device 22, flows back into the compressor 21, is compressed, and is discharged in a high-temperature, high-pressure gas state. This cycle is repeated during heating operation of the refrigeration cycle device 1.

Here, a method for controlling the rotation speed of the heat source side blower 24 will be described with reference to FIG. 6. FIG. 6 is a flowchart showing a method for controlling the rotation speed of the heat source side blower 24 according to the first embodiment. First, the control device 100 determines whether the operation mode is cooling operation (step S1). If the operation mode is cooling operation (step S1: YES), the control device 100 determines whether the heat medium temperature is lower than the outdoor air temperature (step S2). If the heat medium temperature is lower than the outdoor air temperature (step S2: YES), the control device 100 controls the rotation speed of the heat source side blower 24 to a rotation speed within a first range (step S3). If the heat medium temperature is equal to or higher than the outdoor air temperature (step S2: NO), the control device 100 controls the rotation speed of the heat source side blower 24 to a rotation speed within a second range (step S4).

If the operation mode is heating operation (step S1: NO), the control device 100 determines whether the heat medium temperature is higher than the outdoor air temperature (step S5). If the heat medium temperature is higher than the outdoor air temperature (step S5: YES), the control device 100 controls the rotation speed of the heat source side blower 24 to a rotation speed within a first range (step S6). If the heat medium temperature is equal to or lower than the outdoor air temperature (step S5: NO), the control device 100 controls the rotation speed of the heat source side blower 24 to a rotation speed within a second range (step S7).

As described above, according to the refrigeration cycle apparatus 1 of the first embodiment, when the heat medium heat exchanger 41 is functioning effectively, the rotation speed of the heat source side blower 24 is controlled to a rotation speed within a first range, which is a range of rotation speeds lower than the rotation speed during rated operation. Therefore, the refrigeration cycle apparatus 1 can suppress the power consumption related to the operation of the heat source side blower 24 and improve the energy saving performance.

For example, in general, when heating is performed when the outdoor air temperature is low, below 2°C, the evaporation temperature drops as it is pulled by the low-temperature outdoor air, and the necessary heating capacity cannot be secured. One solution is to increase the rotation speed of the heat source side blower, but depending on the outdoor air temperature, the necessary heating capacity cannot be secured even if the rotation speed is increased to the maximum. In contrast, according to the present embodiment, which recovers heat from well water, the evaporation temperature rises by controlling the rotation speed of the heat source side blower 24 to within a first range, which is a range of rotation speeds lower than the rotation speed during rated operation, and therefore it is possible to secure heating capacity.

Furthermore, by lowering the rotation speed of the heat source side blower 24 or stopping the heat source side blower 24, it is possible to suppress the formation of frost on the heat source side heat exchanger 23. This reduces the frequency or time of defrosting operation to remove frost that has formed on the heat source side heat exchanger 23 during heating operation, and therefore the duration of heating operation can be extended.

In addition, by reducing the rotation speed of the heat source side blower 24 or stopping the heat source side blower 24, the generation of noise associated with the operation of the heat source side blower 24 can be suppressed.

Embodiment 2.
Fig. 7 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the refrigeration cycle apparatus 1A according to embodiment 2. As shown in Fig. 7, the refrigeration cycle apparatus 1A of embodiment 2 differs from the refrigeration cycle apparatus 1A of embodiment 1 in that it has a second bypass pipe 502 and a second bypass valve 53. The following mainly describes the differences from embodiment 1, and a description of the commonalities will be omitted.

The heat source unit 2A has a second bypass pipe 502 and a second bypass valve 53. The second bypass pipe 502 is a pipe that connects the suction side of the compressor 21 and the downstream side of the heat medium heat exchanger 41 based on the flow of refrigerant during heating operation. The second bypass valve 53 is provided in the second bypass pipe 502, and switches between an open state that allows the flow of refrigerant and a closed state that blocks the flow of refrigerant.

FIG. 8 is a functional block diagram showing a refrigeration cycle apparatus 1A according to the second embodiment. As shown in FIG. 8, the control device 100 is communicatively connected to the second bypass valve 53 by wire or wirelessly, and controls the open/close state of the second bypass valve 53. Specifically, the control device 100 opens the second bypass valve 53 during heating operation, and closes the second bypass valve 53 during cooling operation.

Next, the heating operation will be described with reference to FIG. 7, focusing on the differences from the first embodiment. The control device 100 performs the heating operation by switching the flow path switching device 22 so that the suction side of the compressor 21 and the heat source side heat exchanger 23 are connected. The control device 100 also opens the second bypass valve 53. At this time, a part of the refrigerant in the superheated gas state that flows out of the heat medium heat exchanger 41 flows into the heat source side heat exchanger 23, and the remaining part flows into the second bypass piping 502. The refrigerant that flows into the heat source side heat exchanger 23 exchanges heat with the outdoor air supplied by the heat source side blower 24, and the degree of superheat increases. The refrigerant in the superheated gas state that flows out of the heat source side heat exchanger 23 passes through the flow path switching device 22 and merges with the refrigerant that passed through the second bypass piping 502. The refrigerant in the superheated gas state then passes through the accumulator 26 and flows back into the compressor 21, where it is compressed and discharged in a high-temperature, high-pressure gas state. This cycle is repeated during heating operation of the refrigeration cycle device 1A.

According to the refrigeration cycle apparatus 1A of the second embodiment, as in the first embodiment, when the heat medium heat exchanger 41 is functioning effectively, the rotation speed of the heat source side blower 24 is controlled to a rotation speed within a first range, which is a range of rotation speeds lower than the rotation speed during rated operation. Therefore, the refrigeration cycle apparatus 1A can suppress the power consumption related to the operation of the heat source side blower 24 and improve the energy saving performance.

Furthermore, according to the second embodiment, a portion of the refrigerant flowing toward the heat source side heat exchanger 23 during heating operation is bypassed to the second bypass pipe 502. Therefore, the refrigeration cycle apparatus 1A of the second embodiment can reduce the flow rate of the refrigerant passing through the heat source side heat exchanger 23 more than the refrigeration cycle apparatus 1A of the first embodiment, and can reduce the rotation speed of the heat source side blower 24. Therefore, the refrigeration cycle apparatus 1A of the second embodiment can further improve the energy saving performance.

Embodiment 3.
Fig. 9 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of the refrigeration cycle apparatus 1B according to embodiment 3. As shown in Fig. 9, the refrigeration cycle apparatus 1B of embodiment 3 differs from the refrigeration cycle apparatus 1B of embodiment 1 mainly in that it has a relay unit 6. The following description will focus on the differences from embodiment 1, and will omit a description of the commonalities.

The refrigeration cycle device 1B is connected between the heat source device 2B and the load device 3 and auxiliary heat source device 4, and is equipped with a relay device 6, which is a flow distribution unit that distributes the refrigerant into multiple flow paths.

The heat source unit 2B and the relay unit 6 are connected by a high-pressure main pipe 801 and a low-pressure main pipe 802 through which the refrigerant flows. Here, the high-pressure main pipe 801 is a pipe through which a high-pressure refrigerant flows, and the low-pressure main pipe 802 is a pipe through which a low-pressure refrigerant flows. The relay unit 6 and the load device 3 are connected by branch pipes 803a and 804a through which the refrigerant flows. The relay unit 6 and the load device 3 are connected by branch pipes 803b and 804b through which the refrigerant flows. The relay unit 6 and the auxiliary heat source unit 4 are connected by branch pipes 803c and 804c through which the refrigerant flows. The load devices 3a and 3b and the auxiliary heat source unit 4 are connected in parallel to the relay unit 6.

The heat source unit 2B has a compressor 21, a flow path switching device 22, a heat source side heat exchanger 23, a heat source side blower 24, a heat source side throttle device 25, an accumulator 26, and check valves 28a to 28d.

Check valves 28a to 28d allow refrigerant to flow only in a specified direction. Check valve 28a allows refrigerant to flow only from the relay 6 to the flow path switching device 22. Check valve 28b allows refrigerant to flow only from the flow path switching device 22 to the relay 6. Check valve 28c allows refrigerant to flow only from the relay 6 to the heat source side heat exchanger 23. Check valve 28d allows refrigerant to flow only from the heat source side heat exchanger 23 to the relay 6.

The relay unit 6 has a first refrigerant heat exchanger 61, a second refrigerant heat exchanger 62, a relay unit throttling device 63, a relay unit bypass throttling device 64, on-off valves 711a-711c and 712a-712c, and check valves 721a-721c and 722a-722c.

The first refrigerant heat exchanger 61 and the second refrigerant heat exchanger 62 are, for example, double-tube, plate, or shell-and-tube heat exchangers. The first refrigerant heat exchanger 61 and the second refrigerant heat exchanger 62 exchange heat between the refrigerants.

The repeater throttle device 63 and the repeater bypass throttle device 64 are solenoid valves whose opening degree is variably controlled. The repeater throttle device 63 is connected in series with the first refrigerant heat exchanger 61 and adjusts the flow rate of the refrigerant flowing through the first refrigerant heat exchanger 61. The repeater bypass throttle device 64 is provided in the repeater bypass piping 503 that connects the downstream side of the second refrigerant heat exchanger 62 and the downstream side of the on-off valves 712a to 712c and circulates a portion of the refrigerant flowing between the load device 3 and the auxiliary heat source device 4 to the heat source device 2B. The repeater bypass throttle device 64 is connected in parallel with the check valves 722a to 722c and adjusts the flow rate of the heat medium flowing downstream of the on-off valves 712a to 712c via the second refrigerant heat exchanger 62 and the first refrigerant heat exchanger 61.

The on-off valve 711a is a valve that can be selectively switched between an open state that allows the flow of refrigerant between the high-pressure main pipe 801 and the branch pipe 803a, and a closed state that blocks the flow of refrigerant. The on-off valve 711b is a valve that can be selectively switched between an open state that allows the flow of refrigerant between the high-pressure main pipe 801 and the branch pipe 803b, and a closed state that blocks the flow of refrigerant. The on-off valve 711c is a valve that can be selectively switched between an open state that allows the flow of refrigerant between the high-pressure main pipe 801 and the branch pipe 803c, and a closed state that blocks the flow of refrigerant.

The on-off valve 712a is a valve that can be selectively switched between an open state that allows refrigerant to flow between the low-pressure main pipe 802 and the branch pipe 803a, and a closed state that blocks the flow of refrigerant. The on-off valve 712b is a valve that can be selectively switched between an open state that allows refrigerant to flow between the low-pressure main pipe 802 and the branch pipe 803b, and a closed state that blocks the flow of refrigerant. The on-off valve 712c is a valve that can be selectively switched between an open state that allows refrigerant to flow between the low-pressure main pipe 802 and the branch pipe 803c, and a closed state that blocks the flow of refrigerant.

Check valves 721a-721c and 722a-722c allow refrigerant to flow only in a specified direction. Check valve 721a allows refrigerant to flow only in the direction from load device 3a to relay unit 6. Check valve 721b allows refrigerant to flow only in the direction from load device 3b to relay unit 6. Check valve 721c allows refrigerant to flow only in the direction from auxiliary heat source unit 4 to relay unit 6. Check valve 722a allows refrigerant to flow only in the direction from relay unit 6 to load device 3a. Check valve 722b allows refrigerant to flow only in the direction from relay unit 6 to load device 3b. Check valve 722c allows refrigerant to flow only in the direction from relay unit 6 to auxiliary heat source unit 4.

Figure 10 is a functional block diagram showing a refrigeration cycle apparatus 1B relating to embodiment 3. As shown in Figure 10, the control device 100 is connected to the compressor 21, the flow path switching device 22, the heat source side blower 24, the heat source side throttling device 25, the load side blower 32, the load side throttling device 33, the on-off valves 711a-711c and 712a-712c, the auxiliary side throttling device 42, the pump 43, the repeater throttling device 63, and the repeater bypass throttling device 64 so as to be able to communicate wirelessly or by wire. The control device 100 controls the connection direction of the flow path switching device 22, the open/closed state of the on-off valves 711a-711c and 712a-712c, and the open/closed state of the repeater throttling device 63 to switch the operation mode. The control device 100 controls the rotation speed of the compressor 21, the rotation speed of the heat source side blower 24, the opening degree of the heat source side throttling device 25, the rotation speed of the load side blower 32, the opening degree of the load side throttling device 33, the repeater throttling device 63, the repeater bypass throttling device 64, the opening degree of the auxiliary side throttling device 42, and the rotation speed of the pump 43 so that the indoor air temperature measured by the indoor air temperature sensor 34 becomes the temperature set by the user. In addition, the control device 100 controls the opening degree of the repeater bypass throttling device 64 so that the refrigerant in the liquid state or two-phase state flows through the repeater 6 bypass piping during heating operation.

In particular, during cooling operation, when the heat medium temperature is lower than the outdoor air temperature, the control device 100 controls the rotation speed of the heat source side blower 24 to within the first range described in embodiment 1. Similarly, during heating operation, when the heat medium temperature is higher than the outdoor air temperature, the control device 100 controls the rotation speed of the heat source side blower 24 to within the first range.

However, the control device 100 may block the flow of refrigerant to the heat medium heat exchanger 41 when it is determined that the heat medium heat exchanger 41 does not function effectively as a condenser in cooling operation or as an evaporator in heating operation. Specifically, the control device determines that the heat medium heat exchanger does not function effectively as a condenser when the heat medium temperature is equal to or higher than the outdoor air temperature during cooling operation. Similarly, the control device determines that the heat medium heat exchanger does not function effectively as an evaporator when the heat medium temperature is equal to or lower than the outdoor air temperature during heating operation. The control device 100 also blocks the flow of refrigerant to the heat medium heat exchanger 41 by closing the auxiliary side throttling device 42. Note that during heating operation, the relay bypass throttling device 64 is further opened to ensure a refrigerant flow path from the relay unit 6 to the heat source unit 2. In this case, the refrigeration cycle device 1B functions in the same way as a refrigeration cycle device without an auxiliary heat source unit 4, so the control device 100 controls the rotation speed of the heat source side blower 24 to within a second range, which is a range of rotation speeds that includes the rotation speed during rated operation.

The operation of the refrigeration cycle device 1B and the flow of the refrigerant will be described. First, the cooling operation will be described with reference to FIG. 9. The control device 100 performs cooling operation by switching the flow path switching device 22 so that the discharge side of the compressor 21 and the heat source side heat exchanger 23 are connected. The control device 100 also opens the on-off valves 712a, 712b, and 711c, and closes the on-off valves 711a, 711b, and 712c. Furthermore, the control device 100 opens the relay bypass throttle device 64. At this time, the high-temperature, high-pressure gas refrigerant discharged from the compressor 21 flows into the heat source side heat exchanger 23 through the flow path switching device 22. The refrigerant that flows into the heat source side heat exchanger 23 exchanges heat with the air supplied by the heat source side blower 24, condenses, and liquefies, becoming a medium-temperature, high-pressure two-phase refrigerant. The medium-temperature, high-pressure two-phase refrigerant that flows out of the heat source side heat exchanger 23 passes through the heat source side throttle device 25, the check valve 28d, and the high-pressure main pipe 801 and flows into the relay unit 6.

The medium-temperature, high-pressure two-phase refrigerant that flows into the relay unit 6 is separated into a gas-rich refrigerant and a liquid-rich refrigerant. The gas-rich refrigerant flows into the auxiliary heat source unit 4 through the on-off valve 711c, and is condensed and liquefied by heat exchange with the heat medium in the heat medium heat exchanger 41 that operates as a condenser, becoming a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the heat medium heat exchanger 41 is depressurized in the auxiliary side throttling device 42 to become a low-temperature, medium-pressure liquid or two-phase refrigerant, and then passes through the branch pipe 804c and the check valve 721c to merge with the liquid-rich refrigerant that flows out of the relay unit throttling device 63.

The liquid-rich refrigerant is cooled and condensed in the first refrigerant heat exchanger 61, becoming a low-temperature, high-pressure liquid. The low-temperature, high-pressure liquid is decompressed in the relay throttling device 63, becoming a low-temperature, medium-pressure liquid or two-phase refrigerant, and then merges with the condensed and liquefied refrigerant in the heat medium heat exchanger 41. The low-temperature, medium-pressure liquid or two-phase refrigerant is then cooled and condensed in the second refrigerant heat exchanger 62, becoming a low-temperature, medium-pressure liquid refrigerant.

The low-temperature, medium-pressure liquid refrigerant flows into the load device 3 through the check valves 722a and 722b and the branch pipes 804a and 804b, and is reduced in pressure by the load-side throttle device 33 to become a low-temperature, low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the load-side heat exchanger 31, where it exchanges heat with the indoor air in the load-side heat exchanger 31, which operates as an evaporator, and evaporates to become a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant that flows out of the load-side heat exchanger 31 flows into the heat source unit 2B through the branch pipes 803a and 803b, the opening/closing valves 712a and 712b, and the low-pressure main pipe 802.

The high-temperature, low-pressure gas refrigerant that flows into the heat source unit 2B passes through the check valve 28a, the flow path switching device 22, and the accumulator 26, and then returns to the compressor 21.

Next, the heating operation will be described with reference to FIG. 11. FIG. 11 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the refrigeration cycle device 1B according to the third embodiment. The control device 100 performs heating operation by switching the flow path switching device 22 so that the suction side of the compressor 21 and the heat source side heat exchanger 23 are connected. The control device 100 also opens the on-off valves 711a, 711b, and 712c, closes the on-off valves 712a, 712b, and 711c, and closes the relay throttle device 63. At this time, the high-temperature, high-pressure gas refrigerant discharged from the compressor 21 flows into the relay 6 through the flow path switching device 22, the check valve 28b, and the high-pressure main pipe 801. The gas refrigerant that flows into the relay 6 flows into the load device 3 through the on-off valves 711a and 711b and the branch pipes 803a and 803b.

The high-temperature, high-pressure gas refrigerant that flows into the load device 3 flows into the load-side heat exchanger 31, where it exchanges heat with the indoor air in the load-side heat exchanger 31 that operates as a condenser, and is condensed and liquefied to become a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the load-side exchanger is depressurized in the load-side throttle device 33 to become a low-temperature, medium-pressure liquid or two-phase refrigerant. The low-temperature, medium-pressure liquid or two-phase refrigerant then passes through the branch pipes 804a and 804b and the check valves 721a and 722b, and is cooled in the second inter-refrigerant heat exchanger 62, where it is condensed and liquefied to become a low-temperature, medium-pressure liquid refrigerant. A portion of the low-temperature, medium-pressure liquid refrigerant is bypassed, and the remaining portion is depressurized in the relay bypass throttle device 64 to become a low-temperature, low-pressure two-phase refrigerant, and is then heated in the second inter-refrigerant heat exchanger 62 and the first inter-refrigerant heat exchanger 61.

Meanwhile, the bypassed low-temperature, medium-pressure liquid refrigerant flows into the auxiliary heat source unit 4 through the check valve 722c and the branch pipe 804c. The low-temperature, medium-pressure liquid refrigerant that flows into the auxiliary heat source unit 4 is depressurized by the auxiliary side throttle device 42 to become a low-temperature, low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the heat medium heat exchanger 41, where it exchanges heat with the heat medium in the heat medium heat exchanger 41 operating as an evaporator, evaporating and vaporizing, becoming a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant then flows into the relay unit 6 through the branch pipe 803c.

The low-temperature, low-pressure two-phase refrigerant heated in the second refrigerant heat exchanger 62 and the first refrigerant heat exchanger 61 merges with the high-temperature, low-pressure gas refrigerant that has passed through the on-off valve 712c, and then flows into the heat source unit 2B through the low-pressure main pipe 802.

The low-temperature, low-pressure two-phase refrigerant that flows into the heat source unit 2B passes through the check valve 28c and the heat source side throttle device 25 and flows into the heat source side heat exchanger 23. The refrigerant that flows into the heat source side heat exchanger 23 exchanges heat with the air supplied by the heat source side blower 24 and evaporates, becoming a high-temperature, low-pressure gas or two-phase refrigerant. The high-temperature, low-pressure gas or two-phase refrigerant that flows out of the heat source side heat exchanger 23 passes through the flow switching device 22 and the accumulator 26 and returns to the compressor 21.

As described above, according to the refrigeration cycle apparatus 1B of the third embodiment, as in the first embodiment, when the heat medium heat exchanger 41 is functioning effectively, the rotation speed of the heat source side blower 24 is controlled to a rotation speed within a first range, which is a range of rotation speeds lower than the rotation speed during rated operation. Therefore, the refrigeration cycle apparatus 1B can suppress the power consumption related to the operation of the heat source side blower 24 and improve the energy saving performance.

Embodiment 4.
Fig. 12 is a refrigerant circuit diagram showing the flow of refrigerant during cooling operation of a refrigeration cycle apparatus 1C according to embodiment 4. As shown in Fig. 12, the refrigeration cycle apparatus 1C according to embodiment 3 differs from embodiment 2 in the configurations of a heat source unit 2C and a relay unit 6A, and in the configuration of the refrigerant piping connecting the heat source unit 2C and the relay unit 6A. The following mainly describes the differences from embodiment 3, and a description of the commonalities will be omitted.

The heat source unit 2C and the relay unit 6A are connected by a high-pressure gas pipe 805 through which a refrigerant flows. Here, the high-pressure gas pipe 805 is a pipe through which a high-pressure gas refrigerant flows, the low-pressure gas pipe 806 is a pipe through which a low-pressure gas refrigerant flows, and the liquid pipe 807 is a pipe through which a liquid refrigerant flows.

The heat source unit 2C has a compressor 21, flow path switching devices 22 and 22b, a heat source side heat exchanger 23, a heat source side blower 24, a heat source side throttle device 25, and an accumulator 26.

The flow path switching devices 22a and 22b switch between cooling operation, in which the heat source side heat exchanger 23 functions as a condenser, and heating operation, in which the heat source side heat exchanger 23 functions as an evaporator. The flow path switching devices 22 and 22b are, for example, four-way valves, and are controlled by the control device 100. The flow path switching device 22a connects the discharge side of the compressor 21 to the relay unit 6 during cooling operation, and connects the discharge side of the compressor 21 to the relay unit 6 during heating operation. The flow path switching device 22b connects the discharge side of the compressor 21 to the heat source side heat exchanger 23 during cooling operation, and connects the flow path switching device 22 to the suction side of the compressor 21 to the heat source side heat exchanger 23 during heating operation.

The relay unit 6A has a first refrigerant heat exchanger 61, a second refrigerant heat exchanger 62, a relay unit throttling device 63, a relay unit bypass throttling device 64, on-off valves 711a-711c and 712a-712c, and check valves 721a-721c and 722a-722c.

The on-off valve 711a is a valve that can be selectively switched between an open state that allows the flow of refrigerant between the low-pressure gas pipe 806 and the branch pipe 803a, and a closed state that blocks the flow of refrigerant. The on-off valve 711b is a valve that can be selectively switched between an open state that allows the flow of refrigerant between the low-pressure gas pipe 806 and the branch pipe 803b, and a closed state that blocks the flow of refrigerant. The on-off valve 711c is a valve that can be selectively switched between an open state that allows the flow of refrigerant between the low-pressure gas pipe 806 and the branch pipe 803c, and a closed state that blocks the flow of refrigerant.

The on-off valve 712a is a valve that can be selectively switched between an open state that allows the flow of refrigerant between the high-pressure gas pipe 805 and the branch pipe 803a, and a closed state that blocks the flow of refrigerant. The on-off valve 712b is a valve that can be selectively switched between an open state that allows the flow of refrigerant between the high-pressure gas pipe 805 and the branch pipe 803b, and a closed state that blocks the flow of refrigerant. The on-off valve 712c is a valve that can be selectively switched between an open state that allows the flow of refrigerant between the high-pressure gas pipe 805 and the branch pipe 803c, and a closed state that blocks the flow of refrigerant.

FIG. 13 is a functional block diagram showing a refrigeration cycle apparatus 1C according to embodiment 4. As shown in FIG. 13, the control device 100 is connected to the compressor 21, the flow path switching devices 22a and 22b, the heat source side blower 24, the heat source side throttling device 25, the load side blower 32, the load side throttling device 33, the on-off valves 711a-711c and 712a-712c, the auxiliary side throttling device 42, the pump 43, the repeater throttling device 63, and the repeater bypass throttling device 64 wirelessly or by wire so as to be able to communicate with them. The control device 100 controls the connection direction of the flow path switching devices 22a and 22b and the open/closed state of the on-off valves 711a-711c and 712a-712c to switch the operation mode.

In particular, during cooling operation, when the heat medium temperature is lower than the outdoor air temperature, the control device 100 controls the rotation speed of the heat source side blower 24 to within the first range described in embodiment 1. Similarly, during heating operation, when the heat medium temperature is higher than the outdoor air temperature, the control device 100 controls the rotation speed of the heat source side blower 24 to within the first range.

However, the control device 100 may block the flow of refrigerant to the heat medium heat exchanger 41 when it is determined that the heat medium heat exchanger 41 does not function effectively as a condenser in cooling operation or as an evaporator in heating operation. Specifically, the control device determines that the heat medium heat exchanger does not function effectively as a condenser when the heat medium temperature is equal to or higher than the temperature of the outdoor air during cooling operation. Similarly, the control device determines that the heat medium heat exchanger does not function effectively as an evaporator when the heat medium temperature is equal to or lower than the temperature of the outdoor air during heating operation. In addition, the control device 100 blocks the flow of refrigerant to the heat medium heat exchanger 41 by closing the auxiliary side throttle device 42. In this case, the refrigeration cycle device 1C functions in the same way as a refrigeration cycle device without an auxiliary heat source unit 4, so the control device 100 controls the rotation speed of the heat source side blower 24 to within a second range that is a range of rotation speeds that includes the rotation speed during rated operation.

The operation of the refrigeration cycle device 1C and the flow of the refrigerant will be described. First, the cooling operation will be described with reference to FIG. 12. The control device 100 performs cooling operation by switching the flow path switching device 22a to a direction that connects the discharge side of the compressor 21 to the relay unit 6, and switching the flow path switching device 22b to a direction that connects the discharge side of the compressor 21 to the heat source side heat exchanger 23. The control device 100 also opens the on-off valves 711a, 711b, and 712c, and closes the on-off valves 712a, 712b, and 711c. At this time, part of the high-temperature, high-pressure gas refrigerant discharged from the compressor 21 flows into the relay unit 6A through the high-pressure gas pipe 805, and the remainder flows into the heat source side heat exchanger 23 through the flow path switching device 22b. The refrigerant that flows into the relay unit 6A flows into the auxiliary heat source unit 4 through the on-off valve 712c and the branch pipe 803c, and is condensed and liquefied by heat exchange with the heat medium in the heat medium heat exchanger 41 that operates as a condenser, becoming a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant then flows into the relay unit 6A through the auxiliary side throttle device 42, the branch pipe 804c, and the check valve 721c.

Meanwhile, the refrigerant that flows into the heat source side heat exchanger 23 exchanges heat with the air supplied by the heat source side blower 24, and a portion of it condenses and liquefies, becoming a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the heat source side heat exchanger 23 flows into the relay unit 6A through the heat source side throttle device 25 and the liquid piping 807. The low-temperature, high-pressure liquid refrigerant that flows into the relay unit 6A passes through the first inter-refrigerant heat exchanger 61, merges with the low-temperature, high-pressure liquid refrigerant that has passed through the check valve 721c, and then passes through the second inter-refrigerant heat exchanger 62. The low-temperature, high-pressure liquid refrigerant flows into the load device 3 through the check valves 722a and 722b and the branch piping 804a and 804b.

The low-temperature, high-pressure liquid refrigerant that flows into the load device 3 is depressurized by the flow control valve to become a low-temperature, low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the load-side heat exchanger 31, where it exchanges heat with the indoor air in the load-side heat exchanger 31, which operates as an evaporator, and evaporates to become a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant that flows out of the load-side heat exchanger 31 flows into the relay unit 6A through the branch pipes 803a and 803b and the on-off valves 711a and 711b, and further flows into the heat source unit 2C through the low-pressure gas pipe 806.

The high-temperature, low-pressure gas refrigerant that flows into the heat source unit 2C passes through the accumulator 26 and returns to the compressor 21.

Next, the heating operation will be described with reference to FIG. 14. FIG. 14 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the refrigeration cycle device 1C according to embodiment 4. The control device 100 performs heating operation by switching the flow path switching device 22a to a direction that connects the discharge side of the compressor 21 to the relay device 6, and switching the flow path switching device 22b to a direction that connects the suction side of the compressor 21 to the heat source side heat exchanger 23. In addition, the control device 100 opens the on-off valves 712a, 712b, and 711c, and closes the on-off valves 711a, 711b, and 712c. At this time, the high-temperature, high-pressure gas refrigerant discharged from the compressor 21 flows into the relay device 6A through the high-pressure gas pipe 805. The high-temperature, high-pressure gas refrigerant that has flowed into the relay device 6A flows into the load device 3 through the on-off valves 712a and 712b and the branch pipes 803a and 803b.

The high-temperature, high-pressure gas refrigerant that flows into the load device 3 flows into the load-side heat exchanger 31, where it exchanges heat with the indoor air in the load-side heat exchanger 31 that operates as a condenser, and condenses and liquefies to become a low-temperature, high-pressure liquid refrigerant. The low-temperature, high-pressure liquid refrigerant that flows out of the load-side heat exchanger 31 is depressurized in the load-side throttling device 33 to become a low-temperature, medium-pressure liquid or two-phase refrigerant. The low-temperature, medium-pressure liquid or two-phase refrigerant then passes through the branch pipes 804a and 804b and the check valves 721a and 721b. A portion of the low-temperature, medium-pressure liquid or two-phase refrigerant that has passed through the check valves 721a and 721b passes through the relay throttling device 63 and the first inter-refrigerant heat exchanger 61 to flow into the heat source unit 2C, and the remainder passes through the second inter-refrigerant heat exchanger 62, the check valve 722c, and the liquid pipe 807 to flow into the auxiliary heat source unit 4. The low-temperature, medium-pressure liquid or two-phase refrigerant that flows into the heat source unit 2C is depressurized by the heat source side throttle device 25 to become a low-temperature, low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the heat source side heat exchanger 23, where it exchanges heat with the air supplied by the heat source side blower 24 and evaporates, becoming a high-temperature, low-pressure gas or two-phase refrigerant.

Meanwhile, the low-temperature, medium-pressure liquid or two-phase refrigerant that flows into the auxiliary heat source unit 4 is depressurized by the auxiliary side throttle device 42 to become a low-temperature, low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the heat medium heat exchanger 41, where it exchanges heat with the heat medium in the heat medium heat exchanger 41, which operates as an evaporator, and evaporates to become a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant that flows out of the heat medium heat exchanger 41 flows into the heat source unit 2C through the branch pipe 803c, the on-off valve 711c, and the low-pressure gas pipe 806.

Then, the high-temperature, low-pressure gas or two-phase refrigerant merges with the high-temperature, low-pressure gas refrigerant that has passed through the flow path switching device 22b, passes through the accumulator 26, and returns to the compressor 21.

As described in the first embodiment, when the rotation speed of the heat source side blower 24 is minimum, the control device 100 may stop the heat source side blower 24 if it determines that the heat exchange amount in the heat source side heat exchanger 23 and the heat medium heat exchanger 41 is excessive for the indoor load. FIG. 15 is a refrigerant circuit diagram showing the flow of refrigerant during heating operation of the refrigeration cycle device 1C according to the fourth embodiment. In this case, as shown in FIG. 15, the control device 100 closes the relay throttling device 63. As a result, all of the low-temperature and medium-pressure liquid or two-phase refrigerant that flows out of the load device 3 and passes through the check valves 721a and 721b flows into the auxiliary heat source unit 4 through the second refrigerant heat exchanger 62, the check valve 722c, and the liquid piping 807. The low-temperature and medium-pressure liquid or two-phase refrigerant that flows into the auxiliary heat source unit 4 is decompressed by the auxiliary side throttling device 42 to become a low-temperature and low-pressure two-phase refrigerant. The low-temperature, low-pressure two-phase refrigerant then flows into the heat medium heat exchanger 41, where it exchanges heat with the heat medium in the heat medium heat exchanger 41, which operates as an evaporator, and evaporates to become a high-temperature, low-pressure gas refrigerant. The high-temperature, low-pressure gas refrigerant that flows out of the heat medium heat exchanger 41 flows into the heat source unit 2C through the branch pipe 803c, the on-off valve 711c, and the low-pressure gas pipe 806. The high-temperature, low-pressure gas or two-phase refrigerant then flows through the accumulator 26 and returns to the compressor 21.

The above is an explanation of the embodiments, but the present disclosure is not limited to the above embodiments, and various modifications and combinations are possible without departing from the spirit of the present disclosure.

For example, FIG. 16 is a refrigerant circuit diagram showing a refrigeration cycle apparatus 1D according to a modified example. In the refrigeration cycle apparatus 1D shown in FIG. 16, the heat source unit 2D and the load unit 3 are connected by a heat medium pipe 602, and the heat source unit 2D and the auxiliary heat source unit 4 are connected by a heat medium pipe 603. The heat source unit 2D has a compressor 21, a flow switching device 22, a heat source side heat exchanger 23, a first heat source side heat medium heat exchanger 71, a throttling device 72, a second heat source side heat medium heat exchanger 73, and a throttling device 74, and these are connected by piping to form a refrigerant circuit.

The first heat source side heat medium heat exchanger 71 exchanges heat between the refrigerant flowing in the refrigerant circuit and a heat medium such as water flowing in the heat medium piping 602. The second heat source side heat medium heat exchanger 73 exchanges heat between the refrigerant flowing in the refrigerant circuit and a heat medium such as water flowing in the heat medium piping 602. The throttling devices 72 and 74 reduce the pressure of the refrigerant flowing in the refrigerant circuit to expand it.

A heat medium such as water flows through the heat medium piping 602. The heat medium is pumped out by a pump 75 and circulates between the first heat source side heat medium heat exchanger 71 and the load side heat exchanger 31. A heat medium such as water flows through the heat medium piping 603. The heat medium is pumped out by a pump 76 and circulates between the second heat source side heat medium heat exchanger 73 and the heat medium heat exchanger 41.

The heat source unit 2D supplies cold or hot heat to the load device 3 by performing heat exchange in the first heat source side heat medium heat exchanger 71. The auxiliary heat source unit 4 supplies cold or hot heat to the heat source unit 2D by performing heat exchange in the second heat source side heat medium heat exchanger 73. In this type of refrigeration cycle device 1D, the rotation speed of the heat source side blower 24 is controlled in the same manner as in embodiment 1. Therefore, the refrigeration cycle device 1D can reduce the power consumption related to the operation of the heat source side blower 24 and improve energy saving performance.

1, 1A, 1B, 1C, 1D refrigeration cycle device, 2, 2A, 2B, 2C, 2D heat source unit, 3, 3a, 3b load device, 4 auxiliary heat source unit, 6, 6A relay unit, 21 compressor, 22, 22a, 22b flow path switching device, 23 heat source side heat exchanger, 24 heat source side blower, 25 heat source side throttle device, 26 accumulator, 27 outdoor air temperature sensor, 28a, 28b, 28c, 28d check valve, 31, 31a, 31b load side heat exchanger, 32, 32a, 32b load side blower, 33, 33a, 33b load side throttling device, 34, 34a, 34b indoor air temperature sensor, 41 heat medium heat exchanger, 42 auxiliary side throttling device, 43 pump, 44 first heat medium temperature sensor, 45 second heat medium temperature sensor, 51 first bypass valve, 52 tank, 53 second bypass valve, 61 first refrigerant heat exchanger, 62 second refrigerant heat exchanger, 63: Relay unit throttle device, 64: Relay unit bypass throttle device, 71: First heat source side heat medium heat exchanger, 72: Throttle device, 73: Second heat source side heat medium heat exchanger, 74: Throttle device, 75, 76: Pump, 100: Control device, 101: Processing circuit, 102: Processor, 103: Memory, 104: Bus, 401: First connection pipe, 402: Second connection pipe, 403: Third connection pipe, 501: First bypass pipe, 502: Second bypass gas piping, 503 third bypass piping, 601, 602, 603 heat medium piping, 711a, 712a, 711b, 712b, 711c, 712c, 721a, 722a, 721b, 722b, 721c, 722c on-off valve, 801 high pressure main pipe, 802 low pressure main pipe, 803a, 804a, 803b, 804b, 803c, 804c branch pipes, 805 high pressure gas piping, 806 low pressure gas piping, 807 liquid piping.

Claims (13)

A heat source unit including a compressor that compresses a refrigerant, a heat source side heat exchanger that exchanges heat between the refrigerant and outdoor air, and a heat source side blower that supplies the outdoor air to the heat source side heat exchanger;
A load device having a load-side heat exchanger that exchanges heat between the refrigerant and a fluid that is an object to be heated or cooled;
An auxiliary heat source unit having a heat medium heat exchanger that exchanges heat between a heat medium having heat derived from renewable energy different from the outdoor air and the refrigerant;
a control device that controls the rotation speed of the heat source side blower to be within a first range that is a range of rotation speeds lower than the rotation speed during rated operation, based on a comparison result between the temperature of the heat medium and the temperature of the outdoor air. The heat source unit, the load device, and the auxiliary heat source unit are
2. The refrigeration cycle apparatus according to claim 1, wherein the refrigerant is circulated through the heat source side heat exchanger, the heat medium heat exchanger, and the load side heat exchanger in this order when cooling the fluid, and the refrigerant is circulated through the load side heat exchanger, the heat medium heat exchanger, and the heat source side heat exchanger in this order when heating the fluid. The control device includes:
3. The refrigeration cycle apparatus according to claim 1, wherein when the fluid is cooled and the temperature of the heat medium is lower than the temperature of the outdoor air, a rotation speed of the heat source side blower is controlled to be within the first range. The control device includes:
4. The refrigeration cycle device according to claim 1, wherein when the fluid is heated and the temperature of the heat medium is higher than the temperature of the outdoor air, the rotation speed of the heat source side blower is controlled to be within the first range. 5. The refrigeration cycle device according to claim 1, wherein when the fluid is cooled and the temperature of the heat medium is equal to or higher than the temperature of the outdoor air, the rotation speed of the heat source side blower is controlled to be within a second range that is a range of rotation speeds that includes the rotation speed during rated operation. 6. The refrigeration cycle device according to claim 1, wherein when the fluid is heated and the temperature of the heat medium is equal to or lower than the temperature of the outdoor air, the rotation speed of the heat source side blower is controlled to be within a second range that is a range of rotation speeds that includes the rotation speed during rated operation. The refrigeration cycle apparatus according to any one of claims 1 to 6, wherein the auxiliary heat source unit further includes a pump that circulates the heat medium. The refrigeration cycle apparatus according to claim 7 , wherein the control device controls the pump so as to increase a circulation flow rate of the heat medium when a temperature of the heat medium is lower than a threshold temperature. and an auxiliary side throttle device that adjusts the flow rate of the refrigerant flowing into or out of the heat medium heat exchanger,
The control device includes:
The refrigeration cycle apparatus according to any one of claims 1 to 8, wherein an opening degree of the auxiliary side throttle device is controlled so that the refrigerant flowing out of the heat medium heat exchanger becomes a superheated gas when the fluid is heated. A first bypass pipe that connects a pipe that connects the heat source unit and the auxiliary heat source unit and a pipe that connects the load device and the auxiliary heat source unit;
a first bypass valve provided in the first bypass pipe and switched between an open state that allows the refrigerant to flow and a closed state that blocks the refrigerant from flowing;
The control device includes:
The refrigeration cycle apparatus according to claim 9 , wherein when the fluid is heated and the temperature of the heat medium is lower than a temperature of the outdoor air, the first bypass valve is opened and the auxiliary side throttle device is closed. a second bypass pipe connecting a suction side of the compressor and a downstream side of the heat medium heat exchanger based on a flow of the refrigerant when the fluid is heated;
a second bypass valve provided in the second bypass pipe and switched between an open state that allows the refrigerant to flow and a closed state that blocks the refrigerant from flowing;
The control device includes:
The refrigeration cycle apparatus according to any one of claims 1 to 10, wherein when the fluid is heated, the second bypass valve is opened. A relay unit that relays the flow of the refrigerant between the heat source unit, the load device, and the auxiliary heat source unit is further provided,
The repeater is
a relay bypass pipe for circulating a portion of the refrigerant flowing between the load device and the auxiliary heat source unit to the heat source unit;
The repeater bypass throttling device is provided in the repeater bypass piping and adjusts the flow rate of the refrigerant flowing through the repeater bypass piping.
The control device includes:
The refrigeration cycle apparatus according to claim 9 , wherein when the fluid is heated and the temperature of the heat medium is lower than a temperature of the outdoor air, the relay bypass throttle device is opened and the auxiliary side throttle device is closed. The refrigeration cycle apparatus according to claim 12, wherein the control device controls an opening degree of the relay bypass throttle device so that the refrigerant flows through the relay bypass pipe in a liquid state or a two-phase state.

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