air conditioning

Abstract

An air conditioning system comprises a compressor, an interior heat exchanger, and an exterior heat exchanger. The exterior heat exchanger consists of a first and a second heat exchanger. A control unit operates in two modes: heating, where the first and second heat exchangers function as evaporators and the interior heat exchanger as a condenser; and heating / defrosting, where either the first or second heat exchanger functions as an evaporator, the other of the two heat exchangers functions as a condenser, and the interior heat exchanger also functions as a condenser.If the temperature of the interior heat exchanger, as detected by a temperature sensing unit at the start of heating / defrosting operation, is treated as the first temperature, and the temperature of the interior heat exchanger, as detected by the temperature sensing unit during heating / defrosting operation, is treated as the second temperature, the controller reduces the speed of an interior fan if the second temperature is lower than the first temperature and the difference between the first temperature and the second temperature is greater than or equal to a first setpoint.

Description

Technical field

[0001] The present disclosure relates to an air conditioning system and in particular to an air conditioning system that can perform a heating / defrosting operation in which an outdoor heat exchanger is defrosted and simultaneously heat an interior space. State of the art

[0002] When an air conditioner operates in heating mode, frost can form on the outdoor heat exchanger. The outdoor heat exchanger facilitates heat exchange between the refrigerant flowing through it and the outside air. However, if frost forms on the outdoor heat exchanger, its heat exchange efficiency decreases, and consequently, the air conditioner's heating efficiency also declines.

[0003] It is therefore possible that the air conditioning system will perform a defrost cycle to melt the frost that has formed on the outdoor heat exchanger. During defrosting, the heating operation is stopped, and a four-way valve is switched to the same state as during cooling operation. Similar to cooling operation, the outdoor heat exchanger then operates as a condenser to melt the frost that has formed on it.

[0004] During defrosting, the temperature of the interior heat exchanger, which acts as an evaporator, drops. Therefore, cold air is drawn in from the interior unit if the interior fan remains running. This significantly reduces comfort inside the vehicle. The interior fan is therefore stopped during defrosting. When heating is resumed after defrosting, the interior fan starts rotating again once the interior heat exchanger has warmed up.

[0005] In an air conditioning system described in WO 2017 / 094 148 A1, an outdoor heat exchanger is divided into two sections: an upper section and a lower section. One of the two sections operates as the first heat exchanger and the other as the second heat exchanger. The air conditioning system is equipped with a bypass that directs a portion of the high-temperature / high-pressure refrigerant delivered by the compressor into both the first and second heat exchangers.

[0006] In the air conditioning system described in WO 2017 / 094 148 A1, when the first heat exchanger is defrosted, a control unit connects the bypass to the first heat exchanger by switching a flow reversing valve. As a result, some of the high-temperature / high-pressure refrigerant delivered by the compressor flows through the bypass into the first heat exchanger. This melts the frost that has formed on the first heat exchanger. Meanwhile, the second heat exchanger continues to operate as an evaporator, thus maintaining heating operation in the interior heat exchanger.

[0007] Similarly, in the air conditioning system described in WO 2017 / 094 148 A1, the control system connects the bypass to the second heat exchanger during defrosting by switching a flow reversing valve. Consequently, the first heat exchanger can be operated as an evaporator while the second heat exchanger is being defrosted.

[0008] In this way, the air conditioning system described in WO 2017 / 094 148 A1 can operate in a heating / defrosting mode, in which heating continues in the indoor heat exchanger while two outdoor heat exchangers are alternately defrosted. This prevents a loss of indoor comfort even during defrosting.

[0009] Document JP H04-344056A discloses an air conditioning system comprising a control unit connected to the motor of a propeller fan of a condenser. The control unit is configured to control the motor such that the speed of the propeller fan is reduced when, during operation, the temperature difference between the air conditioned by the condenser and a preset temperature exceeds a preset value.

[0010] Document JP 2009 - 133 542 A discloses a refrigeration machine capable of providing cold and hot water. The refrigeration machine comprises a compressor, a hot water supply heat exchanger, an electronic expansion valve, a cold water heat exchanger, and a heat source-side heat exchanger, which form a circuit. A control unit is provided to control the compressor according to the storage state of a hot water supply tank, which stores water that has been heated by the hot water supply heat exchanger. Brief description of the invention; Technical problem statement

[0011] Since, as described above, heating is generally interrupted during defrosting, the temperature of the interior drops and comfort decreases.

[0012] In contrast, during the heating / defrosting operation described in patent document 1, the heating operation continues and warm air can be supplied. However, it is possible that the heating output will be lower than during normal heating operation. Under these circumstances, the temperature of the air supplied by the indoor unit decreases. This lowers the room temperature and reduces comfort in the room, although not to the same extent as during defrosting operation.

[0013] The present disclosure was developed to solve the aforementioned problems, one objective of which is to provide an air conditioning system which prevents the temperature of a room from decreasing during heating / defrosting operation and maintains the same level of comfort in the interior. Solution to the problem

[0014] The invention is defined by the combination of the features of independent claim 1. Preferred embodiments are defined in the dependent claims.

[0015] An air conditioning system according to an embodiment of the present disclosure comprises a compressor having an intake port for drawing in refrigerant and an outlet port for discharging refrigerant, an interior heat exchanger connected to the compressor outlet port and operated as a condenser during heating operation, an exterior heat exchanger connected to the compressor intake port and operated as an evaporator during heating operation, a bypass line connected to the compressor outlet port, a flow direction reversing device arranged between the bypass line and the exterior heat exchanger, an interior fan supplying air to the interior heat exchanger, a temperature sensing unit configured to detect the temperature of the interior heat exchanger, and a control unit.The outdoor heat exchanger comprises a first heat exchanger and a second heat exchanger with independent refrigerant flow channels. The flow direction reversing device connects or disconnects the first heat exchanger and the bypass line, and connects or disconnects the second heat exchanger and the bypass line by switching according to a control signal from the controller. The controller operates in two modes: a heating mode, in which the first and second heat exchangers operate as evaporators and the interior heat exchanger as a condenser, and a heating / defrosting mode, in which either the first or the second heat exchanger operates as an evaporator, with the other heat exchanger acting as a condenser, and the interior heat exchanger as a condenser.If the temperature of the interior heat exchanger measured by the temperature sensing unit at the start of heating / defrosting operation is considered the first temperature, and the temperature of the interior heat exchanger measured by the temperature sensing unit during heating / defrosting operation is considered the second temperature, the controller reduces the speed of the interior blower if, during heating / defrosting operation, the second temperature is lower than the first temperature and the difference between the first and second temperatures is greater than or equal to a first setpoint. Advantageous effects of the invention

[0016] With an air conditioning system according to an embodiment of the present disclosure, it is possible to prevent the temperature of a room from dropping, and to maintain the same level of comfort in the interior during heating / defrosting operation. Brief description of the characters Fig. Figure 1 shows a configuration drawing to illustrate the configuration of an air conditioning system according to embodiment 1. Fig. Figure 2 shows a representation describing a method for controlling the speed of an interior blower in an air conditioning system according to embodiment 1. Fig. Figure 3 shows a flowchart to illustrate the procedure for controlling the speed of the interior blower of an air conditioning system according to embodiment 1. Fig. Figure 4 shows a configuration drawing to illustrate the configuration of an air conditioning system according to embodiment 2. Fig. Figure 5 shows a configuration drawing to illustrate the configuration of an air conditioning system according to embodiment 3. Fig. Figure 6 shows a configuration drawing to illustrate the configuration of an air conditioning system according to embodiment 4. Fig. Figure 7 shows a representation illustrating the states of a first flow direction switching device and a second flow direction switching device in the respective operating modes of an air conditioning system according to embodiments 1 to 4. Description of embodiments

[0017] The following describes embodiments of an air conditioning system 100 according to the present disclosure with reference to the figures. The present disclosure is not limited to embodiments 1 to 4 below, and various modifications may be made without departing from the core of the present disclosure. Furthermore, the present disclosure includes all combinations resulting from the configurations illustrated in embodiments 1 to 4 described below. In the figures, elements designated with the same reference numerals are identical or substantially identical, and this applies to the entire description in this document. It should be noted that in the figures, the ratios between the relative sizes or shapes of the individual components may differ from the actual ratios or shapes. Design 1

[0018] Fig. Figure 1 shows a configuration drawing to illustrate the configuration of an air conditioner 100 according to embodiment 1. As in Fig. As shown in Figure 1, the air conditioner 100 is a split-type air conditioner in which an outdoor unit 1 and an indoor unit 2 are connected, for example, via refrigerant lines and electrical lines. The air conditioner 100 comprises a cooling circuit, an air supply unit, and a control system.

[0019] Cooling circuit 3 comprises a compressor 10, a four-way valve 20, a flow reversing valve 70, an outdoor heat exchanger 50, an expansion valve 30, an indoor heat exchanger 40, a bypass valve 60, a bypass line 80, and refrigerant lines 81, 82, 83, 84, 85, 86A, 86B, 87A, 87B, 88, 89, and 91. During heating operation, the refrigerant in cooling circuit 3 circulates through a refrigerant flow channel in the following sequence: compressor 10, indoor heat exchanger 40, expansion valve 30, and outdoor heat exchanger 50.

[0020] Various types of refrigerants can be used as the refrigerant flowing in cooling circuit 3. For example, R32, R410A or similar refrigerants can be used.

[0021] Cooling circuit 3 is designed so that heating operation, defrosting operation, heating / defrosting operation and cooling operation can be carried out.

[0022] The air supply device comprises an interior blower 400, an interior blower motor 500, an exterior blower 95 and an exterior blower motor 96, which are described below.

[0023] The control system includes a controller 300, a controller 301 and various types of sensors, such as a temperature sensing unit 200, which are described below.

[0024] As in Fig. As shown in Figure 1, the interior heat exchanger 40, the temperature sensing unit 200, the interior blower 400, the interior blower motor 500 and the control unit 301 are housed in the housing of the interior unit 2.

[0025] The interior heat exchanger 40 is connected between refrigerant line 84 and refrigerant line 83. The interior heat exchanger 40 has a heat transfer tube and a heat exchanger fin. The interior heat exchanger 40 facilitates heat exchange between the room air and the refrigerant flowing in the heat transfer tube. The interior heat exchanger 40 operates as a condenser during heating and heating / defrosting operation, and as an evaporator during defrosting and cooling operation.

[0026] The temperature sensing unit 200 is arranged on the interior heat exchanger 40. The temperature sensing unit 200 is designed to record the temperature of the interior heat exchanger 40 at predetermined time intervals. The data recorded by the temperature sensing unit 200 regarding the temperature of the interior heat exchanger 40 are stored in a memory located in the controller 300, which will be described later. The temperature data stored in the memory can only be the most recent temperature data or historical values ​​corresponding to a predetermined period. The temperature sensing unit 200 measures the temperature of the interior heat exchanger 40 during cooling operation, during heating operation, and during heating / defrosting operation.It is noted that the temperature sensing unit 200 can detect the temperature of the refrigerant flowing in the interior heat exchanger 40. Specifically, the temperature sensing unit 200 can measure the surface temperature of the heat transfer tube of the interior heat exchanger 40 and output this temperature as the refrigerant temperature. Alternatively, the temperature sensing unit 200 can also detect the temperature of the heat exchanger fins of the interior heat exchanger 40 as the temperature of the interior heat exchanger 40. Various sensor types, such as a temperature sensor or an infrared sensor, can be used in the temperature sensing unit 200.

[0027] The interior blower 400 is arranged so that room air is directed to the interior heat exchanger 40. If the interior blower 400 is, for example, a cross-flow fan, the interior heat exchanger 40 is located upstream of the interior blower 400.

[0028] The interior blower motor 500 drives the interior blower 400. The control unit 301 regulates the speed of the interior blower 400 by sending a control signal to the interior blower motor 500. The amount of heat exchanged between the refrigerant and the interior air in the interior heat exchanger 40 can be adjusted by changing the speed of the interior blower 400. Data on the speed of the interior blower 400 are stored in a memory of the control unit 301 at predefined intervals. The speed data stored in the memory can only be the most recent speed data or historical values ​​relating to a predefined period.

[0029] The controller 301 has a microcomputer with a processor, a read-only memory (ROM), a random-access memory (RAM), and an input / output (I / O) port. The ROM and RAM are the controller 301's memory. The controller 301 receives a measurement signal from the temperature sensing unit 200 and an operation signal from a control unit, which accepts an operation initiated by a user. Based on the received signals, the controller 301 controls the operation of the entire indoor unit 2, including the indoor heat exchanger 40, the indoor blower motor 500, and the indoor blower 400. The controller 301 of indoor unit 2 and the controller 300 of outdoor unit 1 exchange necessary information. For example, information about the start and end of the heating / defrosting operation is transmitted from the controller 300 of outdoor unit 1 to the controller 301 of indoor unit 2.

[0030] The compressor 10, the four-way valve 20, the expansion valve 30, the external heat exchanger 50, the bypass valve 60, the flow direction reversing valve 70, the control unit 300, the external blower 95 and the external blower motor 96 are housed in the casing of the outdoor unit 1.

[0031] Compressor 10 has an intake port 10a through which refrigerant is drawn in, and an outlet port 10b through which refrigerant is expelled. The intake port 10a of compressor 10 is connected to refrigerant line 91, and the outlet port 10b of compressor 10 is connected to refrigerant line 81. Compressor 10 compresses the low-pressure refrigerant drawn in through refrigerant line 91 and discharges high-pressure refrigerant into refrigerant line 81. Therefore, refrigerant line 91 is an intake line of compressor 10, and refrigerant line 81 is a discharge line of compressor 10. An inverter-driven compressor is used as compressor 10, allowing for an adjustable operating frequency. An operating frequency range is preset for compressor 10.Compressor 10 operates according to a control signal from the controller 300 at a variable operating frequency within the specified operating frequency range. The output of compressor 10 can be adjusted by changing its operating frequency. Various types of compressors can be used as compressor 10. For example, a rotary compressor, a reciprocating compressor, a scroll compressor, a screw compressor, or similar types can be used.

[0032] The four-way valve 20 is a first flow direction switching device by which the flow direction of the refrigerant in the cooling circuit 3 is changed. The four-way valve 20 has four ports E, F, G, and H. Refrigerant line 89 is connected to port E, refrigerant line 91 is connected to port F, refrigerant line 82 is connected to port G, and refrigerant line 83 is connected to port H. Refrigerant line 82 is connected to refrigerant line 81, which is the pressure line of the compressor 10.

[0033] The four-way valve 20 can assume a first state and a second state. In the first state, as in Fig. 1. In the second state, as shown by a solid line, terminal E is connected to terminal F and terminal G to terminal H. In the second state, as shown in Fig. 1. Shown by a dashed line, terminal F is connected to terminal H and terminal E to terminal G. As in Fig. As shown in Figure 7, the four-way valve 20 is set in accordance with a control signal from the controller 300 so that it is in the first position during heating operation and during heating / defrosting operation, and in the second position during defrosting operation and during cooling operation. It should be noted that Fig. Figure 7 shows a representation illustrating the states of a first flow direction switching device and a second flow direction switching device in the respective operating modes of air conditioning systems according to embodiments 1 to 4.

[0034] This section describes a case in which the four-way valve 20 is used as the first flow direction switching device; however, the first flow direction switching device need not necessarily be a four-way valve. A combination of several two-way or three-way valves can also be used as the first flow direction switching device.

[0035] In this way, in the first state, as in Fig. As shown by the solid line in Figure 1, ports E and F of the four-way valve 20 and ports G and H of the four-way valve 20 are connected to each other. Consequently, refrigerant line 82 is connected to refrigerant line 83 and refrigerant line 89 is connected to refrigerant line 91.

[0036] In the second state, as in Fig. As shown by the dashed line in Figure 1, ports G and E of the four-way valve 20 and ports H and F of the four-way valve 20 are connected to each other. Consequently, refrigerant line 82 is connected to refrigerant line 89 and refrigerant line 83 is connected to refrigerant line 91.

[0037] The external heat exchanger 50 is a finned-tube heat exchanger with multiple heat transfer tubes and multiple heat exchanger fins. The external heat exchanger 50 comprises two heat exchangers, 50A and 50B, in which the refrigerant flow channels are independent of each other. Accordingly, a first heat exchanger 50A and a second heat exchanger 50B are connected in parallel in cooling circuit 3. Heat exchanger 50A is arranged vertically above heat exchanger 50B. Hereinafter, the upper heat exchanger 50A will be referred to as the first heat exchanger 50A and the lower heat exchanger 50B as the second heat exchanger 50B. Thus, the first heat exchanger 50A is positioned above the second heat exchanger 50B. The heat exchanger fins of the first heat exchanger 50A may, but do not necessarily have to, be separated from those of the second heat exchanger 50B.

[0038] The first heat exchanger 50A and the second heat exchanger 50B each comprise several heat transfer tubes and several heat exchanger fins. Both the first heat exchanger 50A and the second heat exchanger 50B facilitate heat exchange between the refrigerant flowing through the heat transfer tubes and the outside air supplied by the outside blower 95. During heating operation, the first heat exchanger 50A and the second heat exchanger 50B operate as evaporators, and during cooling and defrosting operation, they operate as condensers. It should be noted that during heating / defrosting operation, either the first heat exchanger 50A or the second heat exchanger 50B operates as the evaporator, and the other of the two heat exchangers operates as the condenser. When operating as a condenser, the first heat exchanger 50A and the second heat exchanger 50B can perform defrosting.During heating / defrosting operation, the first heat exchanger 50A and the second heat exchanger 50B alternately function as a condenser.

[0039] The external blower 95 is arranged such that outside air is directed to the external heat exchanger 50. If the external blower 95 is, for example, a propeller blower, the external heat exchanger 50 is arranged upstream of the external blower 95.

[0040] The external blower motor 96 drives the external blower 95. The control unit 300 controls the external blower motor 96 by outputting a control signal to change the speed of the external blower 95. The amount of heat exchanged between the refrigerant and the outside air in the external heat exchanger 50 can be adjusted by changing the speed of the external blower 95.

[0041] It should be noted that the external blower 95 can consist of one or two blowers. If the external blower 95 consists of one blower, the blower directs air to both the first heat exchanger 50A and the second heat exchanger 50B. If, on the other hand, the external blower 95 consists of two blowers, the two blowers are arranged such that one of the two blowers is positioned above the other.

[0042] One end of refrigerant line 81 is connected to the outlet opening 10b of compressor 10. The other end of refrigerant line 81, one end of bypass line 80, and one end of refrigerant line 82 are connected such that the other end of refrigerant line 81 branches into bypass line 80 and refrigerant line 82. The other end of refrigerant line 82 is connected to port G of four-way valve 20. The other end of bypass line 80 is connected to bypass valve 60.

[0043] Refrigerant line 83 connects port H of the four-way valve 20 to the interior heat exchanger 40. Refrigerant line 84 connects the interior heat exchanger 40 to the expansion valve 30. One end of refrigerant line 85 is connected to the expansion valve 30. The other end of refrigerant line 85, one end of refrigerant line 86A, and one end of refrigerant line 86B are connected at a connection point 73 such that the other end of refrigerant line 85 branches into refrigerant line 86A and refrigerant line 86B.

[0044] The other end of refrigerant line 86A is connected to the first heat exchanger 50A, and the other end of refrigerant line 86B is connected to the second heat exchanger 50B. Refrigerant line 86A has a capillary tube 72A, and refrigerant line 86B has a capillary tube 72B.

[0045] The refrigerant line 87A connects the first heat exchanger 50A to the connection B2 of the flow direction reversing valve 70 and the refrigerant line 87B connects the second heat exchanger 50B to the connection B1 of the flow direction reversing valve 70.

[0046] Refrigerant line 88 connects the bypass valve 60 to port A of the flow reversing valve 70. Refrigerant line 89 connects port C of the flow reversing valve 70 to port E of the four-way valve 20.

[0047] The refrigerant line 91 connects the port F of the four-way valve 20 to the intake port 10a of the compressor 10.

[0048] The expansion valve 30 is an example of a pressure reducer that reduces the pressure of the high-pressure refrigerant flowing through it and releases low-pressure refrigerant. An electronic expansion valve is used as the expansion valve 30, the opening degree of which is adjustable according to a control signal from the controller 300.

[0049] The bypass line 80 is a bypass flow channel for hot gas, through which a portion of the refrigerant discharged from the outlet 10b of the compressor 10 is supplied to the first heat exchanger 50A and the second heat exchanger 50B. The refrigerant supplied by the bypass line 80 is used to defrost the first heat exchanger 50A and the second heat exchanger 50B. The bypass valve 60 is connected to the bypass line 80 as an expansion device. The bypass valve 60 reduces the pressure of the high-pressure refrigerant exiting the outlet 10b of the compressor 10 to an intermediate pressure. When the first heat exchanger 50A is to be defrosted, the refrigerant, whose pressure has been reduced to an intermediate pressure by the bypass valve 60, is directed to the first heat exchanger 50A through the flow direction reversing valve 70.When the second heat exchanger 50B is to be defrosted, the refrigerant, whose pressure has been reduced to an intermediate pressure by the bypass valve 60, is directed to the second heat exchanger 50B through the flow reversing valve 70. It should be noted that an electronic expansion valve is used as the bypass valve 60, the opening degree of which is adjustable according to a control signal from the controller 300; however, the bypass valve 60 is not limited to this application, and a capillary tube can also be used.

[0050] The flow direction reversing valve 70 is an example of the second flow direction reversing device, which reverses the refrigerant flow during heating operation, defrosting operation, cooling operation, and heating / defrosting operation. In accordance with a control signal from the controller 300, the second flow direction reversing device connects or disconnects the first heat exchanger 50A and the bypass line 80, and connects or disconnects the second heat exchanger 50B and the bypass line 80 by switching. Fig. 1. A four-way valve with four ports A, B1, B2, and C is used as the flow direction reversing valve 70. The flow direction reversing valve 70 can assume state I, state II, and state III according to a control signal from the controller 300. In state I, which is in Fig. In state II, as shown by the solid line, port C is connected to port B1 and port C is connected to port B2; however, port A is not connected to either port B1 or port B2. In state II, port A is connected to port B1 and port C is connected to port B2. In state III, port A is connected to port B2 and port C is connected to port B1. With the control provided by the controller 300, the flow reversing valve 70 is set so that it is in state I during heating, defrosting, and cooling operation, and in state II or state III during heating / defrosting operation.

[0051] The 300 controller features a microcomputer with a processor, a read-only memory (ROM), a random-access memory (RAM), and an input / output (I / O) port. The ROM and RAM are the controller's own memory. The 300 controller receives sensing signals from various types of sensors located on the outdoor unit 1 and information transmitted by the indoor unit 2. Based on the received signals and information, the 300 controller adjusts the frequency of the compressor 10 and the speed of the outdoor fan 95, and sets the opening degree of the four-way valve 20, the expansion valve 30, the flow reversing valve 70, and the bypass valve 60.

[0052] Next, the operation of the air conditioner 100 will be described. The air conditioner 100 has four operating modes: cooling mode, heating mode, defrosting mode, and heating / defrosting mode. The difference between defrosting mode and heating / defrosting mode will be explained. Defrosting mode is a mode in which heating is temporarily interrupted to defrost the outdoor heat exchanger 50. In contrast, heating / defrosting mode is a mode in which the outdoor heat exchanger 50 is defrosted while heating is active. The operation of the air conditioner 100 in the four operating modes is described below.

[0053] First, the operation of the air conditioning unit 100 during cooling and defrosting is described. During both cooling and defrosting, the four-way valve 20 is in its second state. In this state, port F is connected to port H, and port E is connected to port G. The flow reversing valve 70 is in state I. In state I, port C is connected to port B1, and port C is connected to port B2. It should be noted that the bypass valve 60 can be open or closed. In the flow reversing valve 70, port B1 is connected to port C, and port B2 is connected to port C. Even if refrigerant is present in the refrigerant line 88, no refrigerant flows from port A to any other port.The settings of the four-way valve 20, the flow direction reversing valve 70 and the bypass valve 60 are the same during cooling operation as during defrosting operation.

[0054] The high-temperature / high-pressure refrigerant exiting the compressor 10's outlet 10b flows through the four-way valve 20, is split at the flow direction reversing valve 70, and flows into the first heat exchanger 50A and the second heat exchanger 50B. During cooling and defrosting operations, both the first heat exchanger 50A and the second heat exchanger 50B operate as condensers. Gaseous refrigerant that flowed into the first heat exchanger 50A and gaseous refrigerant that flowed into the second heat exchanger 50B therefore condense into liquid refrigerant.

[0055] During defrosting, frost forms on both the first heat exchanger 50A and the second heat exchanger 50B. As described above, both the first heat exchanger 50A and the second heat exchanger 50B operate as condensers. Therefore, the frost that has formed on both the first heat exchanger 50A and the second heat exchanger 50B melts due to the heat released by the refrigerant flowing through them. Consequently, both the first heat exchanger 50A and the second heat exchanger 50B are defrosted.

[0056] Liquid refrigerant exiting the first heat exchanger 50A flows into refrigerant line 86A and is decompressed through capillary tube 72A. Liquid refrigerant exiting the second heat exchanger 50B flows into refrigerant line 86B and is decompressed through capillary tube 72B. The liquid refrigerants merge at connection point 73, which connects refrigerant line 86A to refrigerant line 85, and flow into expansion valve 30. The liquid refrigerant is further decompressed by expansion valve 30 and converted into a two-phase, low-pressure refrigerant. The two-phase refrigerant exiting expansion valve 30 flows through refrigerant line 84 into the interior heat exchanger 40.

[0057] During cooling and defrosting operations, the interior heat exchanger 40 functions as an evaporator. The refrigerant flowing into the interior heat exchanger 40 absorbs heat from the room air. This causes the two-phase refrigerant flowing into the interior heat exchanger 40 to evaporate into gaseous, low-pressure refrigerant. Gaseous refrigerant exiting the interior heat exchanger 40 flows through the refrigerant line 83 and the four-way valve 20 and is drawn into the compressor 10 through the intake port 10a. The gaseous refrigerant drawn into the compressor 10 is compressed and converted into gaseous refrigerant at a high temperature and high pressure. During cooling and defrosting operations, the cycle described above is continuously repeated.

[0058] The operation of the air conditioner 100 during heating operation is described next. During the heating process, the four-way valve 20 is in its first state. In this state, port E is connected to port F, and port G is connected to port H. The flow reversing valve 70 is in state I. In state I, port C is connected to port B1, and port C is connected to port B2.

[0059] As a result, the first heat exchanger 50A and the bypass line 80 are not connected, and the second heat exchanger 50B and the bypass line 80 are not connected.

[0060] Compressor 10 draws refrigerant from refrigerant line 91 and compresses it. The compressed refrigerant flows through refrigerant line 81, refrigerant line 82, and the four-way valve 20 into refrigerant line 83.

[0061] The refrigerant is then routed through refrigerant line 83 into the interior heat exchanger 40. The refrigerant is discharged from the compressor 10 and consists of superheated vapor at high temperature and high pressure. The interior heat exchanger 40 facilitates heat exchange between the high-temperature / high-pressure refrigerant and the interior air. This heat exchange causes the refrigerant to condense and liquefy. In this case, the interior heat exchanger 40 operates as a condenser. The liquefied refrigerant flows from the interior heat exchanger 40 into refrigerant line 84. The controller 300 can adjust the speed of the interior blower 400 by outputting a control signal. By adjusting the speed of the interior blower 400, the volume of air directed to the interior heat exchanger 40 is changed, and the amount of heat exchanged between the refrigerant and the air in the interior heat exchanger 40 can be adjusted.

[0062] Refrigerant flowing from the interior heat exchanger 40 into the refrigerant line 84 is directed to the expansion valve 30. The refrigerant is decompressed by the expansion valve 30 and converted into a two-phase, low-pressure refrigerant. The two-phase refrigerant flowing from the expansion valve 30 enters the refrigerant line 85. The controller 300 can adjust the opening degree of the expansion valve 30 by outputting a control signal. The decompression of the refrigerant can be adjusted by setting the opening degree of the expansion valve 30. Increasing the opening degree of the expansion valve 30 increases the pressure of the refrigerant discharged from the expansion valve 30. Conversely, decreasing the opening degree of the expansion valve 30 decreases the pressure of the refrigerant exiting the expansion valve 30.

[0063] The refrigerant, decompressed by the expansion valve 30 and directed into refrigerant line 85, is distributed into refrigerant lines 86A and 86B. Two-phase refrigerant flowing into refrigerant line 86A is further decompressed by the capillary tube 72A and flows into the first heat exchanger 50A. Conversely, two-phase refrigerant flowing into refrigerant line 86B is further decompressed by the capillary tube 72B and flows into the second heat exchanger 50B.

[0064] During heating operation, both the first heat exchanger 50A and the second heat exchanger 50B operate as evaporators. Thus, both the first heat exchanger 50A and the second heat exchanger 50B facilitate heat exchange between the refrigerant flowing through them and the outside air supplied by the outside fan 95, with the refrigerant absorbing heat from the outside air. Consequently, the two-phase refrigerant flowing into the first heat exchanger 50A and the two-phase refrigerant flowing into the second heat exchanger 50B evaporate into superheated, low-pressure refrigerant. The controller 300 can adjust the speed of the outside fan 95 by outputting a control signal.By adjusting the speed of the external blower 95, the volume of air directed to the first heat exchanger 50A and the second heat exchanger 50B is changed, and the amount of heat exchanged between the refrigerant and air in the first heat exchanger 50A and in the second heat exchanger 50B can be adjusted.

[0065] Refrigerant flowing from the first heat exchanger 50A flows into refrigerant line 87A, and refrigerant flowing from the second heat exchanger 50B flows into refrigerant line 87B. The refrigerant flowing in refrigerant line 87A and the refrigerant flowing in refrigerant line 87B are combined by the flow direction reversing valve 70, as shown by the solid line in Fig. As shown in Figure 1, the refrigerant flows from opening C into refrigerant line 89. The refrigerant flowing in refrigerant line 89 passes through the four-way valve 20 and from refrigerant line 91 into the compressor 10. During heating operation, the cycle described above is repeated continuously.

[0066] It should be noted that the bypass valve 60 may be open or fully closed during heating operation. In the flow reversing valve 70, port B1 is connected to port C and port B2 to port C. Thus, even if refrigerant is present in the refrigerant line 88, no refrigerant flows from port A to any other port.

[0067] While the heating operation is carried out as described above, frost may form on the outdoor heat exchanger 50, necessitating defrosting. In this case, it is conceivable that the heating operation is temporarily stopped and switched to defrosting mode, whereby refrigerant at high temperature and high pressure, resulting from the compression carried out by the compressor 10, flows into the outdoor heat exchanger 50. This interrupts the heating operation, causing the room temperature to drop and reducing the comfort of the interior.

[0068] In contrast, during heating / defrosting operation, the flow direction reversing valve 70 is actuated while heating continues, in order to defrost the first heat exchanger 50A and the second heat exchanger 50B alternately. The heating / defrosting operation is described below.

[0069] In heating / defrosting mode, the four-way valve 20 is set to the first position. In the first position, port E is connected to port F and port G to port H. The flow direction reversing valve 70 is switched alternately to position II and position III. In position II, port A is connected to port B1 and port C to port B2. In position III, port A is connected to port B2 and port C to port B1.

[0070] In state II, the first heat exchanger 50A and the bypass line 80 are not connected, while the second heat exchanger 50B is connected to the bypass line 80. In contrast, in state III, the first heat exchanger 50A is connected to the bypass line 80, while the second heat exchanger 50B and the bypass line 80 are not connected to each other.

[0071] If frost forms on the outdoor heat exchanger 50 during heating operation and, for example, the first heat exchanger 50A needs to be defrosted, the flow direction reversing valve 70 is moved to state III. As a result, refrigerant line 88 is connected to refrigerant line 87A and refrigerant line 89 to refrigerant line 87B. Consequently, a portion of the high-temperature / high-pressure refrigerant delivered by compressor 10 flows into bypass line 80. The remainder of the high-temperature / high-pressure refrigerant delivered by compressor 10 flows through refrigerant line 82, four-way valve 20, and refrigerant line 83 into the interior heat exchanger 40. The refrigerant flowing into bypass line 80 is decompressed by bypass valve 60.The decompressed refrigerant flows from the bypass valve 60 through the refrigerant line 88, the flow reversing valve 70, and the refrigerant line 87A into the first heat exchanger 50A to be defrosted. The first heat exchanger 50A is operated as a condenser. The refrigerant flowing into the first heat exchanger 50A condenses and, in doing so, exchanges heat with the frost to defrost the first heat exchanger 50A.

[0072] The amount of refrigerant flowing into the first heat exchanger 50A, which is being defrosted, is adjusted by changing the opening degree of the bypass valve 60. This allows the amount of heat exchanged between the refrigerant and the frost to be controlled. Increasing the opening degree of the bypass valve 60 increases the amount of refrigerant flowing out of the bypass valve 60 outlet, increases the amount of refrigerant flowing into the first heat exchanger 50A, and thus increases the amount of heat exchanged between the refrigerant and the frost. At the same time, the amount of refrigerant flowing into the interior heat exchanger 40 decreases, thereby reducing the heating output. If, on the other hand, the opening degree of the bypass valve 60 is reduced, the amount of refrigerant flowing out of the outlet of the bypass valve 60 decreases, the amount of refrigerant flowing into the first heat exchanger 50A decreases, and the amount of heat exchanged between the refrigerant and the frost decreases.In this case, the amount of refrigerant flowing into the interior heat exchanger 40 increases, and thus the heating output increases. The bypass valve 60 is controlled according to a control signal from the controller 300.

[0073] The refrigerant condensed in the first heat exchanger 50A combines at connection point 73, which connects refrigerant line 86A with refrigerant line 85, with the refrigerant condensed in the interior heat exchanger 40 and decompressed by the expansion valve 30. The resulting refrigerant flows into refrigerant line 86B.

[0074] Refrigerant that has flowed into refrigerant line 86B flows into the second heat exchanger 50B and evaporates. The second heat exchanger 50B then operates as an evaporator. Afterwards, the refrigerant flows back to the compressor 10 through refrigerant line 87B, the flow reversing valve 70, refrigerant line 89, the four-way valve 20, and refrigerant line 91.

[0075] If, however, frost forms on the outdoor heat exchanger 50 during heating operation and, for example, the second heat exchanger 50B needs to be defrosted, the flow direction reversing valve 70 is moved to state II. This connects refrigerant line 88 to refrigerant line 87B and refrigerant line 87A to refrigerant line 89. Consequently, a portion of the high-temperature / high-pressure refrigerant delivered by the compressor 10 flows into the bypass line 80. The remainder of the high-temperature / high-pressure refrigerant delivered by the compressor 10 flows through refrigerant line 82, the four-way valve 20, and refrigerant line 83 into the interior heat exchanger 40. The refrigerant flowing into the bypass line 80 is decompressed by the bypass valve 60.The decompressed refrigerant flows from the bypass valve 60 through the refrigerant line 88, the flow reversing valve 70, and the refrigerant line 87B into the second heat exchanger 50B, which is to be defrosted. The refrigerant flowing into the second heat exchanger 50B condenses during heat exchange with the frost and defrosts the second heat exchanger 50B. In this case, the second heat exchanger 50B operates as a condenser.

[0076] By changing the opening degree of the bypass valve according to a control signal from the controller 300, the amount of refrigerant flowing into the second heat exchanger 50B, which is to be defrosted, is adjusted, and the amount of heat exchanged between the refrigerant and the frost can be set. The process carried out in this case is the same as when the first heat exchanger 50A is to be defrosted, so reference is made to the description above, and a detailed description is omitted here.

[0077] The refrigerant condensed in the second heat exchanger 50B combines at connection point 73, which connects refrigerant line 86B to refrigerant line 85, with the refrigerant condensed in the interior heat exchanger 40 and decompressed by the expansion valve 30. The resulting refrigerant flows into refrigerant line 86A.

[0078] Refrigerant that has flowed into refrigerant line 86A flows into the first heat exchanger 50A and evaporates. The first heat exchanger 50A thus operates as an evaporator. The refrigerant then flows back to the compressor 10 through refrigerant line 87A, the flow reversing valve 70, refrigerant line 89, the four-way valve 20, and refrigerant line 91.

[0079] During heating / defrosting operation, the first heat exchanger 50A and the second heat exchanger 50B are defrosted alternately while heating continues. Comparing the case where the first heat exchanger 50A is defrosted with the case where the second heat exchanger 50B is defrosted, the only difference is the state of the flow reversing valve 70. Therefore, when the flow reversing valve 70 is set to state III, the first heat exchanger 50A is defrosted and the second heat exchanger 50B operates as an evaporator. Conversely, when the flow reversing valve 70 is set to state II, the second heat exchanger 50B is defrosted and the first heat exchanger 50A operates as an evaporator. In this way, the first heat exchanger 50A or the second heat exchanger 50B acts as an evaporator, so that the heating operation can continue.It should be noted that during heating / defrosting operation, the first heat exchanger 50A and the second heat exchanger 50B should preferably each be defrosted at least once. Since the water produced by defrosting accumulates in the second heat exchanger 50B, the lower heat exchanger, it is desirable that defrosting be carried out in the following sequence: second heat exchanger 50B, first heat exchanger 50A, and finally second heat exchanger 50B.

[0080] The following describes a problem relating to comfort and a solution based on embodiment 1 in heating / defrosting operation.

[0081] During heating / defrosting operation, the number of external heat exchangers 50 acting as evaporators is reduced to half the number available during normal heating operation. During normal heating operation, both the first heat exchanger 50A and the second heat exchanger 50B in the external heat exchanger 50 operate as evaporators. However, during heating / defrosting operation, either the first heat exchanger 50A or the second heat exchanger 50B in the external heat exchanger 50 operates as an evaporator, and the other of the two heat exchangers acts as a condenser. Therefore, the heating output is likely to decrease. When the heating output decreases, the temperature of the internal heat exchanger 40 drops, and the air outlet temperature decreases. As a result, the room temperature decreases, and comfort decreases.

[0082] To solve the problem described above, according to embodiment 1, the controller 301 controls the speed of the interior blower 400 as a function of the temperature of the interior heat exchanger 40. A method for controlling the speed of the interior blower 400 is described below using the Fig. 2 and Fig. 3 described. Fig. Figure 2 shows a representation describing a method for controlling the speed of the interior blower 400 in an air conditioning system 100 according to embodiment 1. Fig. Figure 3 shows a flowchart to illustrate a method for controlling the speed of the interior blower 400 of an air conditioning system 100 according to embodiment 1.

[0083] First, a summary of the method for controlling the speed of the interior blower 400 of an air conditioning system 100 according to embodiment 1 is given with reference to Fig. 2 described.

[0084] The controller 301 increases and decreases the speed of the interior blower 400 during heating / defrosting operation, depending on the temperature of the interior heat exchanger 40, which is obtained at the start of the heating / defrosting operation. This allows the controller 301 to perform control measures to prevent the air outlet temperature and the heating output of the interior unit 2 from decreasing excessively during heating / defrosting operation.

[0085] In Fig. 2. At the start of the heating / defrosting operation, the temperature Tem of the interior heat exchanger 40 is T1 °C. The temperature T1 °C therefore serves as the reference. The temperature Tem of the interior heat exchanger 40 is measured by the temperature sensing unit 200. In the following, the temperature T1 °C, which serves as the reference, is referred to as the first temperature. Fig. 2. The rotational speed R1 determined at the start of the heating / defrosting operation is the rotational speed of the interior blower, 400 rpm. Time P1 is the time at which the heating / defrosting operation is started. Time P2 represents the time at which the temperature Tem of the interior heat exchanger reaches 40 (T1 - a) °C. Time P3 represents the time at which the temperature Tem of the interior heat exchanger reaches 40 (T1 + b) °C. Here, a and b ≥ 0, and b ≥ 0, where both are preset values. In the following, a and b are referred to as the first setting a and the second setting b, respectively.

[0086] As in Fig. As shown in Figure 2, the temperature Tem of the interior heat exchanger 40 gradually decreases after the heating / defrosting operation is started at time P1. The temperature sensing unit 200 records the temperature Tem of the interior heat exchanger 40 during the heating / defrosting operation at preset intervals. Hereinafter, the temperature Tem of the interior heat exchanger 40 during the heating / defrosting operation is referred to as the second temperature. The controller 301 gradually reduces the speed Rot of the interior blower 400 when the second temperature is lower than the first temperature and the difference between the first and second temperatures is greater than or equal to the first setpoint a. The controller 301 therefore gradually reduces the speed Rot of the interior blower 400 from the time the second temperature of the interior heat exchanger 40 reaches (T1 - a) °C, i.e., from time P2. In the example of Fig. 2. Controller 301 reduces the speed (Rot) of the interior blower 400 incrementally at predetermined time intervals and at a predetermined reduction rate. However, the method by which the speed (Rot) of the interior blower 400 is reduced is not limited to this case. The speed (Rot) of the interior blower 400 can be reduced linearly at a predetermined reduction rate and in proportion to the elapsed time. The temperature (Tem) of the interior heat exchanger 40 is increased by reducing the speed (Rot) of the interior blower 400, thus preventing the air outlet temperature of the interior unit 2 from decreasing. It should be noted that in this case, it takes some time for the temperature (Tem) of the interior heat exchanger 40 to rise, so that the temperature (Tem) of the interior heat exchanger 40 only begins to rise after a predetermined time interval has elapsed from time P2.

[0087] If the speed of the interior blower 400 (rotary speed) is reduced, the amount of air directed from the blower to the interior heat exchanger 40 decreases accordingly. As a result, the heating output may no longer be sufficient for the interior heating load, and the interior temperature may drop. To prevent this, the lower limit for the speed of the interior blower 400 (rotary speed) can be preset in the controller 301. In this case, the controller 301 will ensure that the speed of the interior blower 400 does not fall below the lower limit. The lower limit is stored in advance in the controller 301's memory.

[0088] Between time P2 and time P3, the temperature Tem of the interior heat exchanger 40 gradually increases because the speed Rot of the interior blower 400 is reduced. The controller 301 incrementally increases the speed Rot of the interior blower 400 when the second temperature is higher than the first temperature and the difference between the first and second temperatures is greater than or equal to the second setpoint b. In other words, the controller 301 incrementally increases the speed Rot of the interior blower 400 from the time when the second temperature of the interior heat exchanger 40 reaches (T1 + b) °C, i.e., from time P3. In the example of Fig. 2. Controller 301 gradually increases the speed of the interior blower 400 at predetermined time intervals and at a predetermined rate of increase. However, the method by which the speed of the interior blower 400 is increased is not limited to this case. The speed of the interior blower 400 can be increased linearly at a predetermined rate of increase and in proportion to the elapsed time. When the speed of the interior blower 400 is increased, the volume of air directed from the interior blower 400 to the interior heat exchanger 40 increases. As a result, the heating output increases relative to the heating load of the interior, thus preventing a drop in room temperature.

[0089] In this way, the controller 301 can prevent the air outlet temperature and the heating output of the indoor unit 2 from decreasing excessively by increasing and decreasing the speed of the indoor blower 400 in relation to the temperature T1, which is the first temperature. This allows a balance to be maintained between the air outlet temperature and the heating output of the indoor unit 2.

[0090] It is noted that the rate of increase of the rotational speed (red) of the interior blower 400 relative to the elapsed time is set to be greater than or equal to the rate of decrease of the rotational speed of the interior blower 400 relative to the elapsed time. In other words, the rate of increase of the rotational speed (red) when increasing the rotational speed (red) of the interior blower 400 is greater than or equal to the rate of decrease of the rotational speed (red) when decreasing the rotational speed of the interior blower 400. Thus, the time interval (P4 - P3) required to increase the rotational speed (red) of the interior blower 400 from R2 to R1 is less than or equal to the time interval (P3 - P2) required to decrease the rotational speed (red) of the interior blower 400 from R1 to R2.

[0091] In the description above, the rate of increase of the rotational speed Rot is described as constant when the rotational speed Rot of the interior fan 400 is increased; however, the rate of increase need not be constant, but can be variable. Similarly, the rate of decrease of the rotational speed Rot is described as constant when the rotational speed of the interior fan 400 is decreased; however, the rate of decrease need not be constant, it can also be variable.

[0092] Next, the procedure for controlling the speed of the interior blower of an air conditioning system 100 according to embodiment 1 will be described using the following examples: Fig. 3 described. The procedure of Fig. 3 occurs during heating / defrosting operation.

[0093] First, in step S1, the controller 301 detects the temperature Tem of the interior heat exchanger 40 using the temperature sensing unit 200 at the start of the heating / defrosting operation and stores the temperature Tem in a memory of the controller 301. The temperature Tem is the temperature T1, which is the first temperature used as a reference. In the example of Fig. 2 is the temperature T1, therefore the temperature Tem at time P1.

[0094] Alternatively, as a further procedure in step S1, the controller 301 can obtain the temperature Tem of the interior heat exchanger 40, which was last measured by the temperature sensing unit 200 during the heating operation of the air conditioning system 100, from the memory of the controller 301 as the first temperature that serves as a reference.

[0095] Then, in step S2, the controller 301 detects the rotational speed of the interior blower 400 (rotary fan) at the start of the heating / defrosting operation. The rotational speed of the red fan is, in this example, Fig. 2 in this case the rotational speed R1 at time P1.

[0096] Alternatively, as a further procedure in step S2, the control unit 301 can obtain the speed last measured during the heating operation of the air conditioning system (100) from the memory of the control unit 301 as the speed at the time of the start of the heating / defrosting operation.

[0097] Next, in step S3, the controller 301 records the temperature Tem of the interior heat exchanger 40 using the temperature sensing unit 200.

[0098] Then, in step S4, controller 301 determines, based on information from controller 300 of outdoor unit 1, whether air conditioner 100 has finished heating / defrosting. If controller 301 determines that air conditioner 100 has finished heating / defrosting, the procedure continues with step S11. If, however, controller 301 determines that air conditioner 100 has not finished heating / defrosting, the procedure continues with step S5.

[0099] In step S5, the controller 301 determines whether the temperature Tem of the interior heat exchanger 40, measured in step S3, is less than or equal to (T1 - a) °C. If the controller 301 determines that the temperature Tem of the interior heat exchanger 40 is greater than (T1 - a) °C, the procedure returns to step S3. If, on the other hand, the controller 301 determines that the temperature Tem of the interior heat exchanger 40 is less than or equal to (T1 - a) °C, the procedure continues with step S6.

[0100] In this way, controller 301 repeats the loop from step S3 to "NO" in step S5, until the determination "YES" is made in step S5. The loop from step S3 to "NO" in step S5 corresponds to the period from time P1 to time P2 in which in Fig. 2. Example shown.

[0101] In the example, step S6 corresponds to... Fig. 2 at time P2. In step S6, the control unit 301 gradually reduces the speed of the interior blower 400.

[0102] Next, in step S7, the controller 301 again records the temperature Tem of the interior heat exchanger 40 using the temperature sensing unit 200. In this case, the temperature Tem is the temperature at the time of heating / defrosting operation, i.e., the second temperature.

[0103] Then, in step S8, controller 301 determines, based on information from controller 300 of outdoor unit 1, whether air conditioner 100 has finished heating / defrosting operation. If controller 301 determines that air conditioner 100 has finished heating / defrosting operation, the procedure continues with step S11. If, however, controller 301 determines that air conditioner 100 has not finished heating / defrosting operation, the procedure continues with step S9.

[0104] In step S9, the controller 301 determines whether the temperature Tem of the interior heat exchanger 40, measured in step S7, is greater than or equal to (T1 + b) °C. If the controller 301 determines that the temperature Tem of the interior heat exchanger 40 is less than (T1 + b) °C, the procedure returns to step S6. If, on the other hand, the controller 301 determines that the temperature Tem of the interior heat exchanger 40 is greater than or equal to (T1 + b) °C, the procedure continues with step S10.

[0105] In this way, controller 301 repeats the loop from step S6 to "NO" in step S9, until "YES" is determined in step S9. The loop from step S6 to "NO" in step S9 corresponds in the example of Fig. 2 the period from time P2 to time P3.

[0106] In the example, step S10 corresponds to... Fig. 2 at time P3. In step S10, the controller 301 gradually increases the speed of the interior blower 400. The procedure then returns to step S3, and the procedure from step S3 to step S10 is repeated.

[0107] In step S11, the air conditioning unit 100 has ended its heating / defrosting operation and is restarting its heating operation. Accordingly, the control unit 301 controls the interior fan 400 at the speed set by the user via a remote control or other device. The rate of change of the interior fan 400's rotational speed can be constant or variable. Alternatively, the rate of change of the interior fan 400's rotational speed can also be changed directly.

[0108] In embodiment 1, the rotational speed of the interior blower 400 is increased and decreased during heating / defrosting operation based on the temperature T1 of the interior heat exchanger 40 determined before the start of heating / defrosting operation. As a result, the controller 301 can perform control measures to prevent the air outlet temperature and the heating output of the interior unit 2 from decreasing excessively during heating / defrosting operation.

[0109] The speed of the interior blower 400 does not need to be reduced gradually, but can also be reduced immediately. However, in this case, the temperature of the interior heat exchanger 40 rises sharply, and the outlet pressure of the interior unit 2 also rises sharply. As a result, the frequency of the compressor 10 may decrease due to the protective control implemented by the compressor 10. This can lead to a decrease in the refrigerant flow rate, reduced defrosting performance, and incomplete frost melting, leaving behind frost. It is also possible that the temperature of the interior heat exchanger 40 will decrease, leading to a deterioration in comfort. Therefore, the speed of the interior blower 400 is preferably not reduced immediately, but gradually over a certain period.

[0110] The speed of the interior fan 400 does not need to be increased gradually, but can also be increased immediately. However, in this case, the temperature of the interior heat exchanger 40 may drop sharply, the air outlet temperature of the interior unit 2 may decrease, and the comfort of the interior may diminish. Furthermore, the user may feel uncomfortable due to a change in the airflow volume or noise. Therefore, the speed of the interior fan 400 is preferably not increased immediately, but gradually over a certain period.

[0111] If the rate of increase of the rotational speed of the interior fan 400 is low, the temperature of the interior heat exchanger 40 may rise sharply during heating / defrosting operation, and the frequency of the compressor 10 may be limited by a condensing pressure protection device. If the frequency of the compressor 10 is limited, the refrigerant flow rate may decrease, defrosting performance may decline, and frost may not melt completely and may remain. It is also possible that the temperature of the interior heat exchanger 40 may decrease, leading to reduced comfort. Therefore, as described above, the rate of increase of the rotational speed of the interior fan 400 should be at least equal to or greater than the rate of decrease of the rotational speed of the interior fan 400.Therefore, according to embodiment 1 as described above, the rate of increase of the rotational speed of the interior blower 400 with respect to the elapsed time is set so that it is greater than or equal to the rate of decrease of the interior blower 400 with respect to the elapsed time.

[0112] Even though the upper limit of the rotational speed of the 400 interior fan does not need to be specified, discomfort to the user due to changes in airflow volume or noise can be prevented by setting the upper limit to the fan speed that the user adjusts using a remote control or other device. In this case, the 301 controller ensures that the fan speed does not exceed the upper limit.

[0113] As described above, a reduction in the air outlet temperature and an excessive reduction in heating output during heating / defrosting operation can be prevented by decreasing and increasing the speed of the interior fan 400 during heating / defrosting operation relative to the temperature T1 of the interior heat exchanger 40 determined before the start of heating / defrosting operation. This enables heating / defrosting operation in which the room temperature is not reduced and comfort is not compromised.

[0114] If the temperature of the interior heat exchanger 40 determined before the start of the heating / defrosting operation is considered the first temperature and the temperature of the interior heat exchanger 40 determined during the heating / defrosting operation is considered the second temperature, the controller 301 according to embodiment 1, as described above, reduces the speed of the interior fan 400 when the second temperature is lower than the first temperature and the difference between the first and second temperatures is greater than or equal to the first setpoint a. Consequently, the temperature of the interior heat exchanger 40 can be increased. This prevents the air outlet temperature of the interior unit 2 from decreasing during the heating / defrosting operation. In this way, according to embodiment 1, the heating / defrosting operation can be carried out in such a way that the room temperature does not decrease and comfort is not compromised.

[0115] According to embodiment 1, the controller 301 increases the speed of the interior fan 400 when the second temperature is higher than the first temperature and the difference between the first and second temperatures is greater than or equal to the second setpoint b. Consequently, a decrease in heating output can be prevented. In this way, according to embodiment 1, the air outlet temperature and the heating output of the interior unit 2 can be prevented from decreasing excessively during heating / defrosting operation. Therefore, according to embodiment 1, the heating / defrosting operation can be carried out in such a way that the room temperature does not drop and comfort is not compromised. Design 2

[0116] Fig. Figure 4 shows a configuration drawing to illustrate the configuration of an air conditioner 100 according to embodiment 2. A difference between Fig. 1 and Fig. 4 consists of the fact that in Fig. 4 four on / off valves 70A, 70B, 70C and 70D instead of the flow direction reversing valve 70 from Fig. 1 are attached.

[0117] In Fig. At point 4, refrigerant line 88 further splits halfway along its length into refrigerant line 88A and refrigerant line 88B. Refrigerant line 88A is connected to refrigerant line 87A at connection point 74. Refrigerant line 88B is connected to refrigerant line 87B at connection point 75.

[0118] In Fig. 4 The refrigerant line 89 branches off at the junction 76 and is connected to the refrigerant line 87A and the refrigerant line 87B.

[0119] The on / off valve 70A is located in refrigerant line 88A. The on / off valve 70B is located in refrigerant line 88B. The on / off valve 70C is installed in refrigerant line 87A between connection point 74 and branch point 76. The on / off valve 70D is installed in refrigerant line 87B between connection point 75 and branch point 76.

[0120] In the embodiment 1 described above, the second flow direction switching device is the flow direction switching valve 70, which consists of a single integrated valve; as shown in Fig. As shown in Figure 4, the second flow direction switching device can be formed from the four on / off valves 70A, 70B, 70C, and 70D. Each of the on / off valves 70A, 70B, 70C, and 70D, for example, includes a solenoid valve. The other configurations correspond to those of Figure 4. Fig. 1 and are therefore given the same reference symbols, their descriptions being omitted here.

[0121] The four on / off valves 70A, 70B, 70C, and 70D form the second flow direction switching device, which reverses the refrigerant flow direction between heating, defrosting, cooling, and heating / defrosting operation. The second flow direction switching device can assume state I, state II, and state III, as described in embodiment 1, by changing the connection points in accordance with a control signal from the controller 300.

[0122] In state I, refrigerant lines 89 and 87A are connected when the on / off valve 70C is open, and refrigerant lines 89 and 87B are connected when the on / off valve 70D is open. In this state, the on / off valves 70A and 70B are closed.

[0123] In state II, refrigerant lines 88 and 87B are connected when on / off valve 70B is open, and refrigerant lines 89 and 87A are connected when on / off valve 70C is open. In this case, on / off valves 70A and 70D are closed.

[0124] In state III, refrigerant lines 88 and 87A are connected when on / off valve 70A is open, and refrigerant lines 89 and 87B are connected when on / off valve 70D is open. On / off valves 70B and 70C are closed.

[0125] When controlled by the 300 controller, the on / off valves 70A, 70B, 70C, and 70D are set so that they are in state I during heating, defrosting, and cooling operation, and in state II or state III during heating / defrosting operation. As described in Fig. As shown in Figure 7, the states of the four-way valve 20, which serves as the first flow direction switching device, and the states of the second flow direction switching device according to embodiment 2 correspond to those of embodiment 1 in each operating mode.

[0126] The other functions correspond to those of embodiment 1, so their description is omitted here.

[0127] In this way, according to embodiment 2, the second flow direction switching device can assume state I, state II, and state III as described in embodiment 1 by opening and closing the on / off valves 70A, 70B, 70C, and 70D. As a result, the air conditioner 100 can perform essentially the same operation as in embodiment 1. Thus, according to embodiment 2, essentially the same effects as in embodiment 1 can also be achieved. embodiment 3

[0128] Fig. Figure 5 shows a configuration drawing to illustrate the configuration of an air conditioner 100 according to embodiment 3. A difference between Fig. 1 and Fig. 5 consists of the fact that in Fig. 5 two three-way valves 600 and 700 instead of the flow direction reversing valve 70 of Fig. 1 are attached. In Fig. At point 5, the refrigerant line 89 branches off at the junction 77 and is connected to the refrigerant line 93 and the refrigerant line 94.

[0129] The three-way valve 600 has three ports: J, K, and L. Port J is connected to refrigerant line 88. Port K is connected to refrigerant line 87A. Port L is connected to refrigerant line 93.

[0130] The three-way valve 700 has three ports: M, N, and P. Port M is connected to refrigerant line 88. Port N is connected to refrigerant line 87B. Port P is connected to refrigerant line 94.

[0131] The other configurations are the same as those of Fig. 1 and are therefore given the same reference symbols, and their description can be omitted here.

[0132] The three-way valves 600 and 700 form the second flow direction switching device, which switches the refrigerant flow direction between heating, defrosting, cooling, and heating / defrosting operation. The second flow direction switching device can assume state I, state II, and state III, as described in embodiment 1, by switching the connection states of the ports of the three-way valves 600 and 700 according to a control signal from the controller 300.

[0133] In state I, the refrigerant line 89 is connected to the refrigerant line 87A via the connection L and the connection K, which are connected to each other, and the refrigerant line 89 is connected to the refrigerant line 87B via the connection P and the connection N, which are connected to each other.

[0134] In state II, the refrigerant line 88 is connected to the refrigerant line 87B via connection M and connection N, which are connected to each other, and the refrigerant line 89 is connected to the refrigerant line 87A via connection L and connection K, which are connected to each other.

[0135] In state III, the refrigerant line 88 is connected to the refrigerant line 87A via connection J and connection K, which are connected to each other, and the refrigerant line 89 is connected to the refrigerant line 87B via connection P and connection N, which are connected to each other.

[0136] When controlled by the 300 controller, the three-way valves 600 and 700 are set so that they are in state I during heating, defrosting, and cooling operation, and in state II or state III during heating / defrosting operation. As described in Fig. As shown in Figure 7, according to embodiment 3, the states of the four-way valve 20, which acts as the first flow direction switching device, and the states of the second flow direction switching device are the same in each operating mode as in embodiment 1.

[0137] The other functions are the same as those of Fig. 1, so their description is omitted here.

[0138] In this way, the second flow direction switching device according to embodiment 3 can assume state I, state II, and state III as described in embodiment 1 when the controller 300 switches the connection states of the ports of the three-way valves 600 and 700. As a result, the air conditioning unit 100 can perform essentially the same operation as in embodiment 1. Thus, essentially the same effects as in embodiment 1 can also be achieved according to embodiment 3. Design 4

[0139] Fig. Figure 6 shows a configuration drawing to illustrate the configuration of an air conditioner 100 according to embodiment 4. A key difference between Fig. 1 and Fig. 6 consists of the fact that in Fig. 6 two four-way valves 800 and 900 instead of the flow direction reversing valve 70 of Fig. 1 are attached. It is assumed that the four-way valves 800 and 900 are differential pressure valves, so a check valve 90 is used to ensure a pressure differential. The configuration of is described below. Fig. 6 described.

[0140] The four-way valve 800 has four ports: Q, R, S, and T. Port R is sealed, preventing refrigerant from escaping. Port S is connected to refrigerant line 93. Port T is connected to refrigerant line 87A. Port Q is described below.

[0141] The four-way valve 900 has four ports: U, V, W, and X. Port V is sealed, preventing refrigerant from escaping. Port W is connected to refrigerant line 94. Port X is connected to refrigerant line 87B. Port U is described below.

[0142] The four-way valve 20, the four-way valve 800, and the four-way valve 900 are all four-way differential pressure valves, each controlled by a pressure difference between the outlet pressure and the intake pressure. Four-way valves with identical construction can be used as four-way valves 20, 800, and 900. It should be noted that port R of the four-way valve 800 is closed, and port V of the four-way valve 900 is closed. Therefore, three-way valves with identical configurations can also be used as four-way valves 800 and 900.

[0143] In Fig. 6 The refrigerant line 88, which is connected to the bypass valve 60, branches at the branch point 105, with one branch of the refrigerant line 88 being connected to the port Q of the four-way valve 800 and the other branch of the refrigerant line 88 being connected to the port U of the four-way valve 900.

[0144] In the refrigerant line 88, a further branch point 106 is arranged between the bypass valve 60 and the branch point 105. The branch point 106 and the check valve 90 are connected by the refrigerant line 93. The check valve 90 and the port E of the four-way valve 20 are connected to each other by the refrigerant line 92.

[0145] The check valve 90 allows the refrigerant flowing from port E of the four-way valve 20 to refrigerant line 88 to pass through, while blocking the refrigerant flowing from refrigerant line 88 to port E. A normally open / closed valve, such as a solenoid valve or a motor-driven valve, is used as the check valve 90, opening and closing according to the control by the controller 300. However, the use of the check valve 90 is not limited to this. A normally open / closed valve that opens and closes based on a pressure differential between the upstream and downstream sides of the valve can also be used as the check valve 90. In this case, the on / off valve is open when the pressure in front of the on / off valve is greater than the pressure behind the on / off valve, and it is closed when the pressure behind the on / off valve is greater than the pressure in front of the on / off valve.In this way, any device can be used as a check valve 90, as long as it allows a refrigerant flow in one direction and blocks a refrigerant flow in the opposite direction.

[0146] One end of refrigerant line 103 is connected to branch point 101, which is located midway along refrigerant line 91. The other end of refrigerant line 103 branches at branch point 104 into refrigerant lines 93 and 94. Refrigerant line 93 is connected to port S of four-way valve 800. Refrigerant line 94 is connected to port W of four-way valve 900.

[0147] Port T of the four-way valve 800 is connected to the first heat exchanger 50A, with the refrigerant line 87A located between them. Port X of the four-way valve 900 is connected to the second heat exchanger 50B, with the refrigerant line 87B located between them.

[0148] It should be noted that the further configuration and functions correspond to those of embodiment 1 and are therefore provided with the same reference numerals, their description being omitted here.

[0149] The four-way valves 800 and 900 form the second flow direction switching device, which reverses the direction of the refrigerant flow between heating, defrosting, cooling, and heating / defrosting operation. The second flow direction switching device can assume state I, state II, and state III, as described in embodiment 1, by switching the connection states of the ports of the four-way valves 800 and 900 according to a control signal from the controller 300.

[0150] In state I, refrigerant line 103 is connected to refrigerant line 87A via connection S and connection T, which are connected to each other, and refrigerant line 103 is connected to refrigerant line 87B via connection W and connection X, which are connected to each other.

[0151] In state II, the refrigerant line 88 is connected to the refrigerant line 87B via the connection U and the connection X, which are connected to each other, and the refrigerant line 103 is connected to the refrigerant line 87A via the connection S and the connection T, which are connected to each other.

[0152] In state III, the refrigerant line 88 is connected to the refrigerant line 87A via the connection Q and the connection T, which are connected to each other, and the refrigerant line 103 is connected to the refrigerant line 87B via the connection W and the connection X, which are connected to each other.

[0153] In accordance with a control signal from the controller 300, the four-way valves 800 and 900 are set to be in state I during heating, defrosting, and cooling operations, and in state II or state III during heating / defrosting operations. As described in Fig. As shown in Figure 7, the states of the four-way valve 20, which serves as the first flow direction switching device, and the states of the second flow direction switching device according to embodiment 4 correspond to those of embodiment 1 in each operating mode.

[0154] The other functions are the same as in embodiment 1, so their description is omitted here.

[0155] In this way, the second flow direction switching device according to embodiment 4 can assume state I, state II, and state III as described in embodiment 1 when the controller 300 switches the connection states of the ports of the four-way valves 800 and 900. As a result, the air conditioning unit 100 can perform essentially the same operation as in embodiment 1. Thus, essentially the same effects as in embodiment 1 can also be achieved according to embodiment 4.

[0156] It should be noted that in embodiments 1 to 4 described above, examples were given in which the operating modes of the air conditioner 100 include defrosting; however, the operating modes of the air conditioner 100 are not limited to this case, and defrosting need not be set as an operating mode. In this case, three types of operating modes are provided, namely cooling, heating, and heating / defrosting. Furthermore, cooling does not need to be set as an operating mode. In this case, two operating modes are available, namely heating and heating / defrosting. Reference symbol list 1 outdoor unit, 2 indoor units, 3 Cooling circuit, 10 Compressor, 10a Intake opening, 10b Outlet opening, 20 four-way valves, 30 Expansion valve, 40 interior heat exchangers, 50 external heat exchangers, 50A first heat exchanger, 50B second heat exchanger, 60 Bypass valve, 70 Flow direction reversing valve, 70A, 70B, 70C, 70D On / Off Valve, 72A capillary tube, 72B capillary tube, 73 liaison point, 74 liaison point, 75 liaison point, 76 Junction, 77 Junction, 80 bypass line, 81 Refrigerant line, 82 Refrigerant line, 83 Refrigerant line, 84 Refrigerant line, 85 Refrigerant line, 86A Refrigerant line, 86B Refrigerant line, 87A Refrigerant line, 87B Refrigerant line, 88 Refrigerant line, 88A Refrigerant line, 88B Refrigerant line, 89 Refrigerant line, 90 Check valve, 91 Refrigerant line, 92 Refrigerant line, 93 Refrigerant line, 94 Refrigerant line, 95 external blowers, 96 External blower motor, 100 air conditioners, 101 Junction, 103 Refrigerant line, 104 Junction, 105 Junction, 106 Junction, 200 temperature detection units, 300 control unit, 301 Control, 400 interior blowers, 500 Interior blower motor, 600 three-way valve, 700 three-way valve, 800 four-way valve, 900 four-way valve.

Claims

Air conditioning system comprising: a compressor (10) having an intake port (10a) designed for drawing in refrigerant and an outlet port (10b) designed for expelling refrigerant; an interior heat exchanger (40) connected to the outlet port (10b) of the compressor (10) and operating as a condenser during heating operation; an exterior heat exchanger (50) connected to the intake port (10a) of the compressor (10) and operating as an evaporator during heating operation; a bypass line (80) connected to the outlet port (10b) of the compressor (10); a flow direction reversing device (70) arranged between the bypass line (80) and the exterior heat exchanger (50); an interior blower (400) directing air to the interior heat exchanger (40); a temperature sensing unit (200) for sensing a temperature of the interior heat exchanger (40); and a control (300,301), wherein the outdoor heat exchanger (50) comprises a first heat exchanger (50A) and a second heat exchanger (50B) whose refrigerant flow channels are independent of each other, the flow direction switching device (70) connects or disconnects the first heat exchanger (50A) and the bypass line (80) according to a control signal from the controller (300, 301) by switching, and connects or disconnects the second heat exchanger (50B) and the bypass line (80) by switching, and the controller (300, 301) is configured to carry out a heating / defrosting operation in which the first heat exchanger (50A) or the second heat exchanger (50B) is operated as an evaporator and the other is operated by the first heat exchanger (50A) and the second heat exchanger (50B) as a condenser, and the indoor heat exchanger (40) is operated as a condenser, wherein when a temperature of the Interior heat exchanger (40),The temperature recorded by the temperature sensing unit (200) at the start of heating / defrosting operation is treated as the first temperature (T1), and the temperature of the interior heat exchanger (40) recorded by the temperature sensing unit (200) during heating / defrosting operation is treated as the second temperature (Tem). The controller (300, 301) is configured to reduce the speed of the interior blower (400) from the speed of the interior blower (400) at the start of heating / defrosting operation if, during heating / defrosting operation, the second temperature (Tem) is lower than the first temperature (T1) and the difference between the first temperature (T1) and the second temperature (Tem) is greater than or equal to a first setpoint (a), otherwise maintaining the speed of the interior blower (400) at the start of heating / defrosting operation. Air conditioning system according to claim 1, wherein the control (300, 301) is configured such that, during heating operation, it causes the first heat exchanger (50A) and the bypass line (80) as well as the second heat exchanger (50B) and the bypass line (80) to be separated from each other by the flow direction switching device (70), that the first heat exchanger (50A) and the second heat exchanger (50B) are operated as evaporators and that the interior heat exchanger (40) is operated as a condenser, and during heating / defrosting operation, it causes the first heat exchanger (50A) or the second heat exchanger (50B) to be connected to the bypass line (80) by the flow direction switching device (70) and the other of the two first and second heat exchangers (50A, 50B) and the bypass line (80) to be separated from each other, that the first heat exchanger (50A) or the second The heat exchanger (50B) and the interior heat exchanger (40) are operated as a condenser,and that the other of the two first and second heat exchangers (50A, 50B) is operated as an evaporator. Air conditioning system according to claim 1 or 2, wherein the control (300, 301) is configured to increase the speed of the interior blower (400) during heating / defrosting operation when the second temperature (Tem) is higher than the first temperature (T1) and the difference between the first temperature (T1) and the second temperature (Tem) is greater than or equal to a second setpoint (b). Air conditioning system according to claim 3, wherein the rate of increase of the rotational speed when increasing the rotational speed of the interior blower (400) is greater than or equal to the rate of reduction of the rotational speed when decreasing the rotational speed of the interior blower (400). Air conditioning system according to one of claims 1 to 4, wherein the control (300, 301) is designed to control the speed of the interior blower (400) so that it does not fall below a lower limit. Air conditioning system according to one of claims 1 to 5, wherein the control (300, 301) is designed to control the speed of the interior blower (400) so that it does not exceed an upper limit. Air conditioning system according to one of claims 1 to 6, wherein the first heat exchanger (50A) is arranged in a vertical direction above the second heat exchanger (50B).

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