Refrigeration cycle device

Abstract

A refrigeration cycle device (100) comprises a compressor (1), a heat exchanger (30), at least one fan (15), a sensor (90), and a control device (8). The compressor (1) discharges a refrigerant. The heat exchanger (30) performs heat exchange between the refrigerant and a heat exchange counterpart. The at least one fan (15) blows air to the heat exchanger. The sensor is provided for acquiring the temperature efficiency of the heat exchanger. The control device executes increase control for increasing the volume of air to be blown by the at least one fan (15).

Description

Refrigeration cycle equipment

[0001] The present disclosure relates to a refrigeration cycle device.

[0002] For example, International Publication No. 2019 / 159282 (Patent Document 1) discloses an air conditioner. This air conditioner includes an outdoor unit and a fan. The outdoor unit includes a heat exchanger (condenser or evaporator) that exchanges heat between a refrigerant and outside air. The fan blows air to the heat exchanger.

[0003] International Publication No. 2019 / 159282

[0004] In the above-mentioned air conditioner, for example, if the difference between the temperature of the refrigerant passing through the heat exchanger and the temperature of the air sent to the heat exchanger is small, a problem may arise in which the efficiency of heat exchange in the heat exchanger decreases.

[0005] The present disclosure has been made to solve such problems, and its purpose is to improve the efficiency of heat exchange in a heat exchanger.

[0006] The refrigeration cycle apparatus of the present disclosure includes a compressor, a heat exchanger, at least one fan, a sensor, and a control device. The compressor discharges a refrigerant. The heat exchanger exchanges heat between the refrigerant and a heat exchange target. The at least one fan blows air to the heat exchanger. The sensor acquires the temperature efficiency of the heat exchanger. The control device executes an increase control to increase the airflow rate of the at least one fan.

[0007] According to the present disclosure, the efficiency of heat exchange in a heat exchanger can be improved.

[0008] It is a diagram showing an example of the configuration of a refrigeration cycle device. It is a functional block diagram of a control device. It is a flowchart showing the flow of processing of the control device. It is a diagram for explaining other examples of the installation position of the fan. It is a diagram for explaining an example in which the second fan is detachable.

[0009] Hereinafter, the present embodiment will be described in detail with reference to the drawings, in which the same or corresponding parts are designated by the same reference numerals and description thereof will not be repeated.

[0010] Embodiment 1. FIG. 1 is a diagram showing an example of the configuration of a refrigeration cycle apparatus 100. The configuration of the refrigeration cycle apparatus 100 according to this embodiment will be described with reference to FIG. 1. The refrigeration cycle apparatus 100 is used, for example, as an air conditioner. The refrigeration cycle apparatus 100 is capable of performing cooling operation and heating operation. The refrigeration cycle apparatus 100 performs cooling operation or heating operation based on a user's operation on a setting device (for example, a remote control). The solid arrows in FIG. 1 indicate the flow of refrigerant during cooling operation. The dashed arrows in FIG. 1 indicate the flow of refrigerant during heating operation.

[0011] 1 , the refrigeration cycle apparatus 100 includes an outdoor unit 101 and an indoor unit 102. The outdoor unit 101 and the indoor unit 102 are connected by a pipe 21 and a pipe 22.

[0012] The outdoor unit 101 includes a compressor 1, a four-way valve 2, a first heat exchanger 31, an expansion valve 41, an outdoor fan 6, and a control device 8. The indoor unit 102 includes a second heat exchanger 32 and an indoor fan 7. The first heat exchanger 31 is also referred to as the "outdoor heat exchanger." The second heat exchanger 32 is also referred to as the "indoor heat exchanger."

[0013] The first heat exchanger 31 and the second heat exchanger 32 are collectively referred to as "heat exchangers 30." The outdoor fan 6 is also referred to as "a fan for the first heat exchanger 31." The indoor fan 7 is also referred to as "a fan for the second heat exchanger 32."

[0014] In this embodiment, both the first heat exchanger 31 and the second heat exchanger 32 are configured with corrugated fins. The fin pitch of the corrugated fins can be changed, for example, during the manufacturing process. By reducing the pitch of the corrugated fins, the heat transfer area can be increased, thereby improving the heat exchange efficiency.

[0015] The refrigerant circuit 10 includes a compressor 1, a four-way valve 2, a first heat exchanger 31, an expansion valve 41, and a second heat exchanger 32. The compressor 1, the four-way valve 2, the first heat exchanger 31, the expansion valve 41, and the second heat exchanger 32 constitute the refrigerant circuit 10. The refrigerant circuit 10 is configured to circulate a refrigerant.

[0016] The refrigerant is used in a refrigeration cycle that transports heat between the outdoor unit 101 and the indoor unit 102. The refrigerant circuit 10 is configured so that during cooling operation, the refrigerant circulates through the compressor 1, four-way valve 2, first heat exchanger 31, expansion valve 41, second heat exchanger 32, and four-way valve 2 in that order. Furthermore, during heating operation, the refrigerant circuit 10 is configured so that the refrigerant circulates through the compressor 1, four-way valve 2, second heat exchanger 32, expansion valve 41, first heat exchanger 31, and four-way valve 2 in that order.

[0017] The compressor 1 is typically an inverter compressor. The compressor 1 is configured to compress a refrigerant. The compressor 1 compresses the refrigerant that flows into the heat exchanger 30 (the first heat exchanger 31 or the second heat exchanger 32). The compressor 1 is configured to compress the refrigerant that it draws in and discharges the refrigerant.

[0018] The four-way valve 2 is configured to switch the flow of refrigerant compressed by the compressor 1 so that it flows to the first heat exchanger 31 or the second heat exchanger 32. The four-way valve 2 has a first port P1 to a fourth port P4. The first port P1 is connected to the discharge side of the compressor 1. The second port P2 is connected to the suction side of the compressor 1. The third port P3 is connected to the first heat exchanger 31. The fourth port P4 is connected to the second heat exchanger 32.

[0019] The four-way valve 2 is configured to allow the refrigerant discharged from the compressor 1 to flow to the first heat exchanger 31 during cooling operation. During cooling operation, the third port P3 is connected to the first port P1 of the four-way valve 2, and the fourth port P4 is connected to the second port P2 of the four-way valve 2. Furthermore, during heating operation, the four-way valve 2 is configured to allow the refrigerant discharged from the compressor 1 to flow to the second heat exchanger 32. During heating operation, the fourth port P4 is connected to the first port P1 of the four-way valve 2, and the third port P3 is connected to the second port P2 of the four-way valve 2.

[0020] The first heat exchanger 31 exchanges heat between a first heat exchange target and the refrigerant. The first heat exchange target is, for example, "air in a first space." The "first space" is typically the "outdoor space" in which the outdoor unit 101 is installed. Specifically, the first heat exchanger 31 is configured to exchange heat between the refrigerant flowing inside the first heat exchanger 31 and the air flowing outside the first heat exchanger 31. The first heat exchanger 31 is configured to function as a condenser that condenses the refrigerant during cooling operation and as an evaporator that evaporates the refrigerant during heating operation. Note that the "heat exchange target" in the present disclosure may be, for example, a liquid or a solid.

[0021] The second heat exchanger 32 exchanges heat between a second heat exchange target and the refrigerant. The second heat exchange target is, for example, "air in the second space." The "second space" is typically the "indoor space" in which the indoor unit 102 is installed. The second heat exchanger 32 is configured to exchange heat between the refrigerant flowing inside the second heat exchanger 32 and the air flowing outside the second heat exchanger 32. The second heat exchanger 32 is configured to function as an evaporator that evaporates the refrigerant during cooling operation and as a condenser that condenses the refrigerant during heating operation.

[0022] Therefore, regardless of whether the system is in cooling operation or heating operation, the refrigerant discharged from the compressor 1 circulates through the condenser, expansion valve 41, evaporator, and compressor 1 in that order. The expansion valve 41 is configured to reduce the pressure of the refrigerant condensed in the condenser by expanding it. The expansion valve 41 is configured to reduce the pressure of the refrigerant condensed by the first heat exchanger 31 during cooling operation, and to reduce the pressure of the refrigerant condensed by the second heat exchanger 32 during heating operation. The expansion valve 41 is, for example, an electromagnetic expansion valve.

[0023] The outdoor fan 6 is configured to send outdoor air to the first heat exchanger 31. In other words, the outdoor fan 6 is configured to supply air to the first heat exchanger 31 in the direction indicated by the arrow α. The outdoor fan 6 includes a first outdoor fan 61 and a second outdoor fan 62.

[0024] The indoor fan 7 is configured to blow indoor air to the second heat exchanger 32. In other words, the indoor fan 7 is configured to supply air to the second heat exchanger 32. The indoor fan 7 includes a first outdoor fan 61 and a second outdoor fan 62. At least one of the outdoor fan 6 and the indoor fan 7 corresponds to the "fan" in the present disclosure. In the example of FIG. 1 , the first outdoor fan 61 and the second outdoor fan 62 are collectively shown as fan 15. The first outdoor fan 61 and the first indoor fan 71 correspond to the "first fan" in the present disclosure. Furthermore, the second outdoor fan 62 and the second indoor fan 72 correspond to the "second fan" in the present disclosure.

[0025] The control device 8 is configured to control each device of the refrigeration cycle device 100. The control device 8 is electrically connected to the compressor 1, the four-way valve 2, the expansion valve 41, the outdoor fan 6, the indoor fan 7, etc., and is configured to control the operation of these devices.

[0026] Furthermore, the control device 8 controls the compressor 1, the expansion valve 41, the fan 15, etc. so that the temperature of the second heat exchange target (for example, room temperature) becomes a set temperature. The set temperature is set, for example, by the user.

[0027] Specifically, the control device 8 performs feedback control on the compressor 1 and the like so that the room temperature becomes the set temperature (so that the room temperature approaches the set temperature). Specifically, the control device 8 controls the operating parameters of the motor of the compressor 1. The operating parameters are, for example, the frequency or rotation speed of the motor. In this embodiment, the operating parameter is the operating frequency of the motor. Hereinafter, the operating frequency is also simply referred to as "frequency."

[0028] The control device 8 has, as its main components, a CPU (Central Processing Unit) 86 and a memory 88. The CPU 86 executes various processes and calculations. The components are interconnected by a data bus. The memory 88 includes a ROM (Read Only Memory) and a RAM (Random Access Memory). The CPU 86 is also referred to as "at least one processor" or "control circuit."

[0029] The ROM stores programs executed by the CPU 86. The RAM temporarily stores data generated by the execution of the programs by the CPU 86. The RAM can function as a temporary data memory used as a working area.

[0030] The outdoor unit 101 further includes a first temperature sensor 91, a second temperature sensor 92, and a third temperature sensor 93. The first temperature sensor 91 detects the temperature of air drawn into the first heat exchanger 31. This temperature is also referred to as the "first intake air temperature." The second temperature sensor 92 detects the temperature of air blown out from the first heat exchanger 31. This temperature is also referred to as the "first outlet air temperature." The third temperature sensor 93 detects the refrigerant temperature after heat exchange in the first heat exchanger 31. Specifically, when the first heat exchanger 31 functions as a condenser, the third temperature sensor 93 detects the condensed refrigerant temperature. When the first heat exchanger 31 functions as an evaporator, the third temperature sensor 93 detects the evaporated refrigerant temperature. The temperature detected by the third temperature sensor 93 is also referred to as the first refrigerant temperature.

[0031] The indoor unit 102 further includes a fourth temperature sensor 94, a fifth temperature sensor 95, and a sixth temperature sensor 96. The fourth temperature sensor 94 detects the temperature of air drawn into the second heat exchanger 32. This temperature is also referred to as the "second intake air temperature." The fifth temperature sensor 95 detects the temperature of air blown out from the second heat exchanger 32. This temperature is also referred to as the "second outlet air temperature." The sixth temperature sensor 96 detects the refrigerant temperature after heat exchange in the second heat exchanger 32. Specifically, when the second heat exchanger 32 functions as a condenser, the sixth temperature sensor 96 detects the condensed refrigerant temperature. When the second heat exchanger 32 functions as an evaporator, the sixth temperature sensor 96 detects the evaporated refrigerant temperature. The temperature detected by the sixth temperature sensor 96 is also referred to as the second refrigerant temperature.

[0032] The first temperature sensor 91, the second temperature sensor 92, the third temperature sensor 93, the fourth temperature sensor 94, the fifth temperature sensor 95, and the sixth temperature sensor 96 are also collectively referred to as a temperature sensor 90 (see FIG. 2 described later). The temperature sensor 90 corresponds to the "sensor" in the present disclosure.

[0033] The first intake air temperature, the first blown air temperature, the first refrigerant temperature, the second intake air temperature, the second blown air temperature, and the second refrigerant temperature are input to the control device 8. Hereinafter, these temperatures are also referred to as the "six temperatures." The control device 8 executes an increase control to increase the airflow rate of the fan 15 based on the six temperatures.

[0034] Next, the increase control will be described. In the present embodiment, the control device 8 executes increase control of the outdoor fan 6 and increase control of the indoor fan 7. First, the increase control of the outdoor fan 6 will be described. When the control device 8 is not executing increase control of the outdoor fan 6, that is, when normal control of the outdoor fan 6 is being executed, the second outdoor fan 62 is not driven, and the first outdoor fan 61 is driven or the first outdoor fan 61 is not driven. Then, when the control device 8 executes increase control of the outdoor fan 6, both the first outdoor fan 61 and the second outdoor fan 62 are driven.

[0035] Next, we will explain the increase control of the indoor fan 7. When the control device 8 is not executing the increase control of the indoor fan 7, that is, when normal control of the indoor fan 7 is being executed, the second indoor fan 72 is not driven, and the first indoor fan 71 is driven or not driven. Then, when the control device 8 executes the increase control of the indoor fan 7, both the first indoor fan 71 and the second indoor fan 72 are driven.

[0036] 2 is a functional block diagram of the control device 8. The control device 8 includes a receiving unit 103, a determining unit 104, a control unit 106, and a storage unit 108.

[0037] The receiving unit 103 acquires the six temperatures described above. The six temperatures include the first intake air temperature detected by the first temperature sensor 91, the first blown air temperature detected by the second temperature sensor 92, the first refrigerant temperature detected by the third temperature sensor 93, the second intake air temperature detected by the fourth temperature sensor 94, the second blown air temperature detected by the fifth temperature sensor 95, and the second refrigerant temperature detected by the sixth temperature sensor 96. These six temperatures are output to the determining unit 104. The determining unit 104 calculates or acquires four parameters, namely, a first parameter, a second parameter, a third parameter, and a fourth parameter. The determining unit 104 then compares these four parameters with corresponding thresholds. The memory unit 108 stores a first condensation threshold Th1c, a first evaporation threshold Th1e, a second threshold Th2, and a third threshold Th3 as the thresholds. The first condensation threshold Th1c and the first evaporation threshold Th1e correspond to the "first threshold" in the present disclosure.

[0038] The first parameter is the temperature efficiency of the condenser. The determination unit 104 calculates the first parameter (temperature efficiency of the condenser) using a predetermined calculation formula. The calculation formula is an absolute value of a value obtained by dividing the first value by the second value. More typically, the calculation formula is the following formula (1).

[0039] Temperature efficiency of condenser = (condenser discharge air temperature - condenser intake air temperature) / (condensed refrigerant temperature - condenser intake air temperature) (1) The numerator on the right side of equation (1) is the difference between the condenser discharge air temperature and the condenser intake air temperature, which corresponds to the "first value" in the present disclosure. Also, the denominator on the right side of equation (1) is the difference between the condensed refrigerant temperature and the condenser intake air temperature, which corresponds to the "second value" in the present disclosure.

[0040] When the temperature difference between the condensing refrigerant temperature and the intake air temperature to the condenser is small, the heat exchange efficiency of the condenser decreases. In this case, the denominator on the right side of equation (1) decreases, and the temperature efficiency of the condenser increases. Furthermore, reducing the fin pitch of the corrugated fins that make up the condenser increases the heat transfer area, but increases the ventilation resistance of the condenser (decreasing the heat exchange efficiency of the condenser). In this case, the temperature of the air blown into the condenser increases, and the temperature efficiency of the condenser increases.

[0041] The temperature efficiency of the condenser is preferably equal to or less than a predetermined value (e.g., 0.8). On the other hand, if the temperature efficiency of the condenser is excessively high, the heat exchange efficiency of the condenser decreases in terms of the "temperature difference between the condensed refrigerant temperature and the temperature of the air drawn into the condenser" and the "ventilation resistance in the condenser." Therefore, in this embodiment, when the temperature efficiency of the condenser is greater than the first condensation threshold Th1c, the airflow rate of the condenser fan is increased. This allows the refrigeration cycle apparatus 100 to promote heat exchange between the refrigerant in the condenser and the air drawn into the condenser, thereby improving the heat exchange efficiency of the condenser. The first condensation threshold Th1c is, for example, 0.8.

[0042] When the first heat exchanger 31 functions as a condenser, the process of increasing the airflow rate of the condenser fan is a control to drive the first outdoor fan 61 and the second outdoor fan 62. When the second heat exchanger 32 functions as a condenser, the process of increasing the airflow rate of the condenser fan is a control to drive the first indoor fan 71 and the second indoor fan 72.

[0043] The second parameter is the temperature efficiency of the evaporator. The determination unit 104 calculates the second parameter (the temperature efficiency of the evaporator) using a predetermined calculation formula. The calculation formula is the absolute value of the value obtained by dividing the third value by the fourth value. More typically, the calculation formula is the following formula (2).

[0044] Evaporator temperature efficiency = (evaporator intake air temperature - evaporator discharge air temperature) / (evaporator intake air temperature - evaporated refrigerant temperature) (2) The numerator on the right side of equation (2) is the difference between the evaporator discharge air temperature and the evaporator intake air temperature, which corresponds to the "third value" in the present disclosure. The denominator on the right side of equation (2) is the difference between the evaporated refrigerant temperature and the evaporator intake air temperature, which corresponds to the "fourth value" in the present disclosure.

[0045] When the temperature difference between the evaporated refrigerant temperature and the intake air temperature to the evaporator is small, the heat exchange efficiency of the evaporator decreases. In this case, the denominator on the right side of equation (2) becomes small, and the temperature efficiency of the evaporator increases.

[0046] The temperature efficiency of the evaporator is preferably equal to or less than a predetermined value (e.g., 0.8). On the other hand, if the temperature efficiency of the evaporator is excessively high, the heat exchange efficiency of the evaporator decreases in terms of the temperature difference between the evaporated refrigerant temperature and the temperature of the air drawn into the evaporator. Therefore, in this embodiment, when the temperature efficiency of the evaporator is greater than the first evaporation threshold Th1e, the air volume of the evaporator fan is increased. This promotes heat exchange between the refrigerant in the evaporator and the air drawn into the evaporator, thereby improving the heat exchange efficiency of the evaporator. The first evaporation threshold Th1e is, for example, 0.8.

[0047] The process of increasing the airflow rate of the evaporator fan is a control to drive the first outdoor fan 61 and the second outdoor fan 62 when the first heat exchanger 31 functions as an evaporator. Furthermore, the process of increasing the airflow rate of the evaporator fan is a control to drive the first indoor fan 71 and the second indoor fan 72 when the second heat exchanger 32 functions as an evaporator. Hereinafter, the process of increasing the airflow rate of the fan is also referred to as "air-increase control."

[0048] The third parameter is the temperature of the intake air to the condenser. If the temperature of the intake air to the condenser is excessively high, the temperature of the condensed refrigerant in the condenser will become excessively high. In this case, an abnormality in the refrigeration cycle apparatus 100 (for example, the compressor 1 may stop) may occur.

[0049] Therefore, the control device 8 of this embodiment increases the airflow rate of the condenser fan when the intake air temperature to the condenser (third parameter) is higher than the second threshold value Th2. This promotes heat exchange in the condenser, thereby lowering the condensed refrigerant temperature in the condenser. Therefore, the control device 8 can suppress the occurrence of an abnormality in the refrigeration cycle apparatus 100 due to an excessively high condensed refrigerant temperature.

[0050] The fourth parameter is the intake air temperature to the evaporator. If the intake air temperature to the evaporator is excessively low, the temperature of the evaporated refrigerant in the evaporator becomes excessively low. In this case, an abnormality in the refrigeration cycle apparatus 100 (for example, the compressor 1 may stop) may occur.

[0051] Therefore, the control device 8 of this embodiment increases the airflow rate of the evaporator fan when the intake air temperature to the evaporator (fourth parameter) is lower than the third threshold value Th3. This promotes heat exchange in the evaporator, thereby lowering the evaporating refrigerant temperature in the evaporator. Therefore, the control device 8 can prevent abnormalities in the refrigeration cycle apparatus 100 caused by an excessively low evaporating refrigerant temperature.

[0052] [Flowchart] Fig. 3 is a flowchart showing the flow of processing by the control device 8. The processing of the flowchart in Fig. 3 is executed, for example, every predetermined period (for example, every second).

[0053] In step S2, it is determined whether the temperature efficiency of the condenser (see formula (1) above) is greater than the first condensation threshold value Th1c. If the temperature efficiency of the condenser is greater than the first condensation threshold value Th1c (YES in step S2), the process proceeds to step S14. In step S14, the control device 8 executes airflow increase control of the condenser fan. Then, the process in FIG. 3 ends.

[0054] If the temperature efficiency of the condenser is equal to or less than the first condensation threshold Th1c (NO in step S2), the process proceeds to step S4. In step S4, it is determined whether the temperature efficiency of the evaporator (see formula (2) above) is greater than the first evaporation threshold Th1e. If the temperature efficiency of the evaporator is greater than the first evaporation threshold Th1e (YES in step S4), the process proceeds to step S16. In step S16, the control device 8 executes airflow increase control of the evaporator fan. The process in FIG. 3 then ends.

[0055] If the temperature efficiency of the evaporator is equal to or less than the first evaporation threshold Th1e (NO in step S4), the process proceeds to step S6. In step S6, it is determined whether the intake air temperature to the condenser is greater than the second threshold Th2. If the intake air temperature to the condenser is greater than the second threshold Th2 (YES in step S6), the process proceeds to step S14. If the intake air temperature to the condenser is equal to or less than the second threshold Th2 (NO in step S6), the process proceeds to step S8.

[0056] In step S8, the control device 8 executes the normal control of the condenser fan (control that does not drive the second fan). Next, in step S10, it is determined whether the intake air temperature to the evaporator is greater than the second threshold value Th2. If the intake air temperature to the evaporator is less than the third threshold value Th3 (YES in step S10), the process proceeds to step S16. If the intake air temperature to the evaporator is equal to or greater than the third threshold value Th3 (NO in step S10), the process proceeds to step S12. In step S12, the control device 8 executes the normal control of the evaporator fan (control that does not drive the second fan). The process of FIG. 3 then ends. As a modified example, the control device 8 may execute the airflow increase control when at least one of the first to fourth parameters is equal to the threshold value corresponding to the parameter.

[0057] [Summary] (1) As described above, the control device 8 executes the airflow increase control when the temperature efficiency of the heat exchanger is greater than the first threshold value. Therefore, the control device 8 can reduce the temperature efficiency, thereby improving the heat exchange efficiency of the heat exchanger.

[0058] In particular, when the first heat exchanger 31 functions as a condenser and the temperature efficiency of the condenser is greater than the first condensation threshold value Th1c, the control device 8 executes airflow increase control of the outdoor fan 6 of the first heat exchanger 31 (step S14 in FIG. 3 ). Furthermore, when the first heat exchanger 31 functions as an evaporator and the temperature efficiency of the evaporator is greater than the first evaporation threshold value Th1e, the control device 8 executes airflow increase control of the outdoor fan 6 of the first heat exchanger 31 (step S16 in FIG. 3 ).

[0059] Furthermore, when the second heat exchanger 32 functions as a condenser and the temperature efficiency of the condenser is greater than the first condensation threshold value Th1c, the control device 8 executes airflow increase control of the indoor fan 7 of the second heat exchanger 32 (step S14 in FIG. 3 ). Furthermore, when the second heat exchanger 32 functions as an evaporator and the temperature efficiency of the evaporator is greater than the first evaporation threshold value Th1e, the control device 8 executes airflow increase control of the indoor fan 7 of the second heat exchanger 32 (step S16 in FIG. 3 ).

[0060] Therefore, the control device 8 can improve the heat exchange efficiency (heat exchange efficiency of the evaporator and the condenser) in the heat exchanger 30. Furthermore, the refrigeration cycle apparatus 100 can suppress a decrease in the heat exchange efficiency due to deterioration of the heat exchanger 30 over time (such as clogging of the fins).

[0061] (2) Furthermore, when the heat exchanger functions as a condenser that condenses refrigerant, the control device 8 executes the air-increase control if the intake air temperature to the heat exchanger is higher than the second threshold value Th2 (YES in step S6 of FIG. 3 ). This prevents the refrigeration cycle apparatus 100 from having an abnormality due to an excessively high condensed refrigerant temperature in the condenser. Furthermore, the control device 8 can operate the refrigeration cycle apparatus 100 over a wide range of intake air temperatures to the heat exchanger.

[0062] (3) Furthermore, the temperature efficiency when the heat exchanger 30 functions as a condenser is calculated using the above formula (1). Therefore, the control device 8 can calculate the temperature efficiency of the condenser through simple calculations.

[0063] (4) When the heat exchanger functions as an evaporator that evaporates the refrigerant, the control device 8 executes the airflow increase control if the intake air temperature to the heat exchanger is lower than the third threshold value Th3 (YES in step S10 of FIG. 3 ). Therefore, it is possible to prevent an abnormality in the refrigeration cycle apparatus 100 due to an excessively low evaporated refrigerant temperature in the evaporator.

[0064] In particular, frost may form on the first heat exchanger 31 of the outdoor unit 101. However, when the temperature of the intake air to the first heat exchanger 31 is lower than the third threshold value Th3, the air increase control is executed, and therefore the sensible heat ratio of the air in the first heat exchanger 31 (the air intake to the first heat exchanger 31 and the air blown out from the first heat exchanger 31) can be increased. Therefore, the refrigeration cycle apparatus 100 can suppress the amount of frost formation on the first heat exchanger 31.

[0065] (5) Furthermore, the temperature efficiency when the heat exchanger 30 functions as an evaporator is calculated using the above formula (2). Therefore, the control device 8 can calculate the temperature efficiency of the evaporator through simple calculations.

[0066] (6) The fans 15 include a first fan (the first outdoor fan 61 and the first indoor fan 71) and a second fan (the second outdoor fan 62 and the second indoor fan 72). When the increase control is not being executed (when the normal control is being executed), the second fan is not driven. In this case, it does not matter whether the first fan is driven or not. The control device 8 executes control to drive the first fan and the second fan as the increase control. Therefore, the control device 8 can achieve airflow increase control with simple control.

[0067] (7) The first heat exchanger 31 and the second heat exchanger 32 are configured with corrugated fins. While reducing the fin pitch of the corrugated fins increases the heat transfer area, there is a concern that the condenser's ventilation resistance increases and the heat exchange efficiency decreases. However, in this embodiment, even if the ventilation resistance increases and the temperature efficiency of the condenser increases, the fins' airflow increase control is executed, so that the decrease in heat exchange efficiency due to the increased ventilation resistance can be suppressed.

[0068] Second Embodiment In the above-described configuration, the third parameter is the temperature of the air suctioned into the condenser. However, the third parameter may be another parameter. For example, the third parameter may be the condensed refrigerant pressure. The condensed refrigerant pressure is the pressure of the refrigerant condensed by the condenser. When such a configuration is adopted, the refrigeration cycle apparatus 100 is equipped with a sensor that detects the condensed refrigerant pressure. The processing of the control device 8 according to the second embodiment adopts the parenthesized notation in step S6.

[0069] If the condensed refrigerant pressure is excessively high, an abnormality in the refrigeration cycle apparatus 100 (such as the compressor 1 stopping) may occur. Therefore, as shown in parentheses in step S6, the control device 8 of this embodiment increases the airflow rate of the condenser fan when the condensed refrigerant pressure is higher than the second threshold value Th2. This reduces the temperature of the air suctioned into the condenser. Therefore, the control device 8 can suppress the occurrence of an abnormality in the refrigeration cycle apparatus 100 due to an excessively high condensed refrigerant pressure in the condenser. The third parameter may be the condensed refrigerant temperature. The condensed refrigerant temperature is the temperature of the refrigerant condensed by the condenser.

[0070] Embodiment 3 In the above-described configuration, the fourth parameter is the intake air temperature to the evaporator. However, the fourth parameter may be another parameter. For example, the fourth parameter may be the evaporated refrigerant pressure. The evaporated refrigerant pressure is the pressure of the refrigerant evaporated by the evaporator. When such a configuration is adopted, the refrigeration cycle apparatus 100 is equipped with a sensor that detects the evaporated refrigerant pressure. The processing of the control device 8 according to embodiment 2 adopts the parenthesized notation in step S10.

[0071] If the evaporated refrigerant pressure is excessively high, an abnormality in the refrigeration cycle apparatus 100 (such as the compressor 1 stopping) may occur. Therefore, as shown in parentheses in step S10, the control device 8 of this embodiment increases the airflow rate of the evaporator fan when the evaporated refrigerant pressure is lower than the second threshold value Th2. This reduces the temperature of the intake air to the evaporator. Therefore, the control device 8 can suppress the occurrence of an abnormality in the refrigeration cycle apparatus 100 due to an excessively low evaporated refrigerant pressure to the evaporator. The fourth parameter may be the evaporated refrigerant temperature.

[0072] Embodiment 4 In the example of Fig. 1, an example has been described in which the first outdoor fan 61 and the second outdoor fan 62 are both installed on the air blowing side of the first heat exchanger 31. Similarly, an example has been described in which the first indoor fan 71 and the second indoor fan 72 are both installed on the air blowing side of the second heat exchanger 32.

[0073] However, the fan may be installed in another position. Fig. 4 is a diagram illustrating another example of the fan installation position. Fig. 4 and Fig. 5 described later are diagrams mainly illustrating the first heat exchanger 31, the first outdoor fan 61, and the second outdoor fan 62. Furthermore, Fig. 4 and Fig. 5 described later show the second heat exchanger 32, the first indoor fan 71, and the second indoor fan 72 in parentheses.

[0074] 4, the first outdoor fan 61 is arranged on the suction side of the first heat exchanger 31, while the second outdoor fan 62 is arranged on the outlet side of the first heat exchanger 31. Even with this configuration, the refrigeration cycle apparatus 100 can achieve the same effects as the above-described embodiment.

[0075] Embodiment 5. In the example of Fig. 1 , a configuration in which the second fan is fixed has been described. However, the second fan may be detachable. Fig. 5 is a diagram for explaining an example in which the second fan is detachable. In Fig. 5 , the second outdoor fan 62 is attached to the detachable member 120. A user or the like can attach the second outdoor fan 62 to the detachable member 120 or detach the second outdoor fan 62 from the detachable member 120.

[0076] This increases the degree of freedom in arranging the second fan. Furthermore, even if the rotation direction of the blades of the first fan and the second fan is opposite to each other, the airflow direction can be unified by arranging the second fan.

[0077] Next, a modification of the above-described embodiment will be described. The refrigeration cycle apparatus 100 of the above-described embodiment is configured to perform both cooling and heating operations. However, the refrigeration cycle apparatus 100 may be configured to perform only one of the cooling and heating operations.

[0078] In the refrigeration cycle apparatus 100 according to the above embodiment, the condition for executing the fan airflow increase control is described as being YES in step S2, YES in step S4, YES in step S6, or YES in step S10. However, a configuration may be adopted in which the condition for executing the fan airflow increase control is at least one of these four conditions.

[0079] In the refrigeration cycle apparatus 100 according to the above embodiment, the outdoor fan 6 includes two fans and the indoor fan 7 includes two fans. However, at least one of the outdoor fan 6 and the indoor fan 7 may include at least three fans. When such a configuration is adopted, the control device 8 drives one of the at least three fans before executing the air flow increase control. Then, the control device 8 drives all of the at least three fans by executing the air flow increase control.

[0080] At least one of the outdoor fan 6 and the indoor fan 7 may be a single fan. In such a configuration, the control device 8 drives the single fan with a reserve of power before executing the airflow increase control. Then, by executing the airflow increase control, the control device 8 drives the single fan to maximize the airflow.

[0081] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0082] (Item 1) A refrigeration cycle device of the present disclosure includes a compressor, a heat exchanger, at least one fan, a sensor, and a control device. The compressor discharges a refrigerant. The heat exchanger exchanges heat between the refrigerant and a heat exchange target. The at least one fan blows air to the heat exchanger. The sensor is a sensor for obtaining the temperature efficiency of the heat exchanger. The control device executes an increase control to increase the airflow rate of the at least one fan.

[0083] (Clause 2) In the refrigeration cycle device described in clause 1, when the heat exchanger functions as a condenser that condenses the refrigerant, the control device executes an increase control when the intake air temperature to the heat exchanger or the condensation pressure of the refrigerant in the heat exchanger is greater than a second threshold value.

[0084] (Item 3) In the refrigeration cycle apparatus according to item 2, when the heat exchanger functions as a condenser, the temperature efficiency is the absolute value of a value obtained by dividing the first value by a second value. The first value is the difference between the temperature of air blown out from the heat exchanger and the temperature of air sucked into the heat exchanger. The second value is the difference between the condensing temperature of the refrigerant in the heat exchanger and the temperature of air sucked into the heat exchanger.

[0085] (4) In the refrigeration cycle device described in any one of paragraphs 1 to 3, when the heat exchanger functions as an evaporator that evaporates refrigerant, the control device executes an increase control when the intake air temperature to the heat exchanger or the evaporation pressure of the refrigerant in the heat exchanger is lower than a third threshold value.

[0086] (Item 5) In the refrigeration cycle apparatus according to any one of Items 1 to 4, when the heat exchanger functions as an evaporator, the temperature efficiency is the absolute value of the third value divided by the fourth value. The third value is the difference between the temperature of air blown out from the heat exchanger and the temperature of air suctioned into the heat exchanger. The fourth value is the difference between the evaporation temperature of the refrigerant in the heat exchanger and the temperature of air suctioned into the heat exchanger.

[0087] (Item 6) In the refrigeration cycle apparatus according to any one of Items 1 to 5, the at least one fan includes a first fan and a second fan. The control device does not drive the second fan when the increase control is not being executed. The control device executes control to drive the first fan and the second fan as the increase control.

[0088] (7) In the refrigeration cycle device according to the 6th aspect, the second fan is detachable.

[0089] (Item 8) In the refrigeration cycle device according to any one of items 1 to 7, the heat exchanger is configured by corrugated fins.

[0090] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0091] REFRIGERATION CYCLE DEVICE, 100 REFRIGERATION CYCLE DEVICE, 101 OUTDOOR UNIT, 102 INDOOR UNIT, 103 RECEIVING UNIT, 104 DETERMINATION UNIT, 106 CONTROL UNIT, 108 MEMORY UNIT, 120 DETACHABLE MEMBERS, 120 ATTACHABLE MEMBER ...

Claims

1. A refrigeration cycle apparatus comprising a compressor that discharges a refrigerant, a heat exchanger that exchanges heat between the refrigerant and a heat exchange target, at least one fan that blows air to the heat exchanger, a sensor for obtaining the temperature efficiency of the heat exchanger, and a control device that executes an increase control for increasing the air volume by the at least one fan, wherein the control device executes the increase control when the temperature efficiency is greater than a first threshold value.

2. The refrigeration cycle apparatus according to claim 1, wherein the control device executes the increase control when the suction air temperature to the heat exchanger or the condensation pressure of the refrigerant in the heat exchanger is greater than a second threshold value in a case where the heat exchanger functions as a condenser that condenses the refrigerant.

3. The temperature efficiency in a case where the heat exchanger functions as the condenser is an absolute value of a value obtained by dividing a first value by a second value, the first value is a difference value between the blown air temperature from the heat exchanger and the suction air temperature to the heat exchanger, and the second value is a difference value between the condensation temperature of the refrigerant in the heat exchanger and the suction air temperature to the heat exchanger. The refrigeration cycle apparatus according to claim 2.

4. The control device executes the increase control when the suction air temperature to the heat exchanger or the evaporation pressure of the refrigerant in the heat exchanger is less than a third threshold value in a case where the heat exchanger functions as an evaporator that evaporates the refrigerant. The refrigeration cycle apparatus according to any one of claims 1 to 3.

5. The temperature efficiency in a case where the heat exchanger functions as the evaporator is an absolute value of a value obtained by dividing a third value by a fourth value, the third value is a difference value between the blown air temperature from the heat exchanger and the suction air temperature to the heat exchanger, and the fourth value is a difference value between the evaporation temperature of the refrigerant in the heat exchanger and the suction air temperature to the heat exchanger. The refrigeration cycle apparatus according to any one of claims 1 to 4.

6. The at least one fan includes a first fan and a second fan, and the control device executes control to drive the first fan and the second fan as the increase control without driving the second fan when the increase control is not being executed. The refrigeration cycle apparatus according to any one of claims 1 to 5.

7. The second fan is detachable. The refrigeration cycle apparatus according to claim 6.

8. The refrigeration cycle device according to any one of claims 1 to 7, wherein the heat exchanger is composed of corrugated fins.

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