Air conditioner

Abstract

In an air conditioner (1), when an indoor heat exchange heating operation is performed, a control unit controls an indoor fan (32) by referring to an indoor fan control table (400) so that an indoor heat exchange temperature (Tc), which is the temperature of an indoor heat exchanger (31), is maintained between 55 DEG C and 57 DEG C for 10 minutes. When the indoor heat exchange temperature (Tc) is less than 55 DEG C, the indoor fan rotation speed (Rfi) is set to a rotation speed lower than the current indoor fan rotation speed (Rfi) by a predetermined rotation speed. When the indoor heat exchange temperature (Tc) is 57 DEG C or more, the indoor fan rotation speed (Rfi) is set to a rotation speed that does not change from the current indoor fan rotation speed (Rfi) or that is higher than the indoor fan rotation speed (Rfi) by a prescribed rotation speed. Thus, by heating the indoor heat exchanger, it is possible to reduce the number of molds and bacteria, and to provide an air conditioner that suppresses the propagation of molds and bacteria.

Description

[0001] This application is based on Chinese National Application No. filed on February 22, 2018

[0002] This application is a divisional application of 2018800145153 (PCT International Application No. PCT / JP2018 / 006445) (air conditioner), and its contents are cited below. Technical Field

[0003] The present invention relates to an air conditioner capable of inhibiting the growth of mold and bacteria in an indoor unit. Background Art

[0004] When the air conditioner performs cooling operation, condensed water is generated in the indoor heat exchanger that functions as an evaporator. Condensed water is the main cause of the growth of mold and bacteria in the indoor heat exchanger. When mold and bacteria grow, the conditioned air blown out from the indoor unit has an unpleasant odor. Therefore, an air conditioner that dries the interior of the indoor unit including the indoor heat exchanger after cooling operation has been proposed (for example, refer to Patent Document 1 or Patent Document 2).

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 10-62000

[0008] Patent Document 2: Japanese Patent Application Publication No. 2016-65687 Summary of the invention

[0009] Technical problem to be solved by the invention

[0010] In the air conditioners described in Patent Documents 1 and 2, the indoor heat exchanger is heated in order to dry the interior of the indoor unit after the cooling operation. However, in the heating for drying as described above, the temperature of the indoor heat exchanger is not much different from the temperature during the heating operation, and does not lead to a reduction in the number of molds and bacteria. Usually, in the operation of drying the interior of the indoor unit as described above, the temperature of the indoor heat exchanger is set to about 40°C, but at this temperature, the growth of molds and bacteria is only suppressed, and when the cooling operation is performed again, the molds and bacteria whose growth has been suppressed may reproduce again.

[0011] The present invention has been developed to solve the above-mentioned problems, and an object of the present invention is to provide an air conditioner that reduces the amount of mold and bacteria by heating an indoor heat exchanger and inhibits the growth of mold and bacteria.

[0012] Technical solutions to solve problems

[0013] In order to solve the above-mentioned technical problems, the air conditioner of the present invention comprises: an indoor heat exchanger; an indoor fan, which generates an airflow to the indoor heat exchanger; and a control unit, which performs heating operation and indoor heat exchange heating operation. In the heating operation, the indoor heat exchanger is made to function as a condenser to deliver warm air into the room. In the indoor heat exchange heating operation, the indoor heat exchanger is made to function as a condenser in a state where condensation water is attached to the indoor heat exchanger, and the temperature of the indoor heat exchanger is maintained above 45 degrees Celsius and below 59 degrees Celsius. In the indoor heat exchange heating operation, the control unit sets a lower limit speed lower than the lower limit speed during the heating operation while maintaining the rotation of the indoor fan.

[0014] Effects of the Invention

[0015] According to the air conditioner of the present invention configured as described above, the number of molds and bacteria can be reduced by heating the indoor heat exchanger, thereby suppressing the growth of molds and bacteria. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is an explanatory diagram of an air conditioner according to an embodiment of the present invention. Figure 1 (A) is a three-dimensional diagram of the indoor and outdoor units. Figure 1 (B) is the X-X section view of (A).

[0017] Figure 2 is an explanatory diagram of an air conditioner according to an embodiment of the present invention. Figure 2 (A) is the refrigerant circuit diagram. Figure 2 (B) is a block diagram of the outdoor unit control unit and the indoor unit control unit.

[0018] Figure 3 This is a flowchart showing the processing flow of the heating operation control.

[0019] Figure 4 This is a flowchart showing the processing flow of the protection control during the heating operation.

[0020] Figure 5 This is data showing the survival rate of mold or bacteria at each indoor heat exchange temperature. Figure 5 (A) is the data about mold, Figure 5 (B) is the data about E. coli.

[0021] Figure 6 This is the control table for each fan during indoor heat exchange heating operation. Figure 6 (A) is the indoor fan control table, Figure 6 (B) is the outdoor fan control table.

[0022] Figure 7 This is a flowchart showing the processing flow of the main routine of the indoor heat exchange heating operation.

[0023] Figure 8 This is a subroutine for indoor heat exchange heating operation and is a flowchart showing the processing flow of pre-heating operation control.

[0024] Fig. 9 This is a subroutine for indoor heat exchange heating operation and is a flowchart showing the processing flow of indoor fan control when the temperature is maintained.

[0025] Fig.10 This is a subroutine for indoor heat exchange heating operation and a flowchart showing the processing flow of outdoor fan control when the temperature is maintained.

[0026] Fig.11 This is a flowchart showing the processing flow of protection control during indoor heat exchange heating operation.

[0027] Fig.12 This is a flowchart showing the processing flow of the wetting control operation.

[0028] Explanation of symbols

[0029] 1…Air Conditioner

[0030] 2…Outdoor unit

[0031] 3…Indoor unit

[0032] 10…Refrigerant circuit

[0033] 21…Compressor

[0034] 27…Outdoor fan

[0035] 32…Indoor fan

[0036] 35…upper and lower wind deflectors

[0037] 71…Discharge temperature sensor

[0038] 72…Outdoor heat exchange temperature sensor

[0039] 73…Outside air temperature sensor

[0040] 74…Indoor heat exchange temperature sensor

[0041] 75…Indoor temperature sensor

[0042] 200…Outdoor unit control unit

[0043] 210…Outdoor unit CPU

[0044] 300…Indoor unit control unit

[0045] 310…Indoor unit CPU

[0046] 400…Indoor fan control table

[0047] 500...Outdoor fan control table

[0048] Tc…Indoor heat exchange temperature

[0049] Tch1…First threshold indoor heat exchange temperature

[0050] Tch2…Second threshold indoor heat exchange temperature

[0051] Tc1 to Tc5: first to fifth threshold indoor heat exchange temperatures

[0052] ΔTc…Indoor heat exchange temperature change

[0053] Te…Outdoor heat exchange temperature

[0054] Teh…Threshold outdoor heat exchange temperature

[0055] Td…Discharge temperature

[0056] Tdh1…First threshold discharge temperature

[0057] Tdh2…Second threshold discharge temperature

[0058] Ti…Indoor temperature

[0059] Tip…Threshold indoor temperature

[0060] To…Outside air temperature

[0061] Top1…First threshold outside air temperature

[0062] Top2…Second threshold outside air temperature

[0063] Top3…Third threshold outside air temperature

[0064] Tp…Set temperature

[0065] ΔT…Temperature difference

[0066] Tch1…First upper and lower indoor heat exchange temperature

[0067] Tch2…The second upper and lower indoor heat exchange temperature

[0068] tp1…first prescribed time

[0069] tp2…Second prescribed time

[0070] tp3…third prescribed time

[0071] tc...Compressor release interval time

[0072] tfi…Indoor fan release interval

[0073] Rc…Compressor speed

[0074] Rcr...Compressor release speed

[0075] Rcm…minimum compressor speed

[0076] Rfi...Indoor fan speed

[0077] Rfia…Indoor fan speed before heating

[0078] Rfir…Indoor fan release speed

[0079] Rfim…Minimum speed of indoor fan

[0080] Rfip…Indoor fan initial speed

[0081] Rfo…Outdoor fan speed

[0082] Rfoa…Outdoor fan speed before heating

[0083] Rfob…Outdoor fan speed when maintaining

[0084] D…Expansion valve opening

[0085] Dp…specified expansion valve opening DETAILED DESCRIPTION

[0086] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. As an embodiment, an air conditioner in which an outdoor unit and an indoor unit are connected by two refrigerant pipes is used as an example for description. In addition, the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

[0087] [Example]

[0088] like Figure 1 As shown in FIG. 1A , the air conditioner 1 of this embodiment includes an outdoor unit 2 installed outdoors, and an indoor unit 3 installed indoors and connected to the outdoor unit 2 via a liquid pipe 4 and a gas pipe 5 .

[0089] <Shape and configuration of indoor unit>

[0090] The indoor unit 3 has an indoor unit housing 30 set in a horizontally long substantially rectangular parallelepiped shape. The indoor unit housing 30 is formed of a top panel 30a, a right side panel 30b, a left side panel 30c, a bottom panel 30d, and a front panel 30e. All of these panels are formed of resin material.

[0091] The top panel 30a is formed in a substantially square shape and forms the top surface of the indoor unit housing 30. Figure 1 As shown in (B) of FIG. 1 , the ceiling panel 30a is provided with an air inlet 30f for taking in room air into the indoor unit 3. Although not shown in the figure, the air inlet 30f is formed in a grid shape.

[0092] The right side panel 30b and the left side panel 30c form the left and right side surfaces of the indoor unit housing 30. The right side panel 30b and the left side panel 30c are formed as curved surfaces having a predetermined curvature and have a bilaterally symmetrical shape.

[0093] The bottom panel 30d is formed in a substantially square shape and forms the bottom surface of the indoor unit housing 30. Figure 1 As shown in (B), a base 30j described later is fixed to the bottom panel 30d.

[0094] The front panel 30e is formed in a substantially square shape, and is arranged so as to cover the front surface of the indoor unit housing 30. The front panel 30e forms a design surface of the indoor unit 3.

[0095] As described above, the top panel 30a is provided with an inlet 30f, and the front panel 30e is provided with an outlet 30g for blowing indoor air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 described later into the room. In the ventilation path 30h connecting the inlet 30f and the outlet 30g, an indoor fan 32 for sucking indoor air from the inlet 30f and blowing it out from the outlet 30g is provided. In addition, the indoor heat exchanger 31 having a bent portion 30n and formed into an inverted V shape is arranged above the indoor fan 32. The indoor heat exchanger 31 and the indoor fan 32 are fixed on a base 30j for mounting the indoor unit 3 on a wall.

[0096] The blow-out port 30g is formed by the lower portion of the base 30j and the lower surface of the casing 30k attached to the front panel 30e. The upper surfaces of the base 30j and the casing 30k are set as a drain pan 30m for receiving condensed water generated in the indoor heat exchanger 31.

[0097] Two up-down wind deflectors 35 are provided at the outlet 30g to deflect the air blown out from the outlet 30g in the up-down direction. The two up-down wind deflectors 35 are each formed of a resin material, and are formed in a shape that each up-down wind deflector 35 can rotate to block the outlet 30g when the indoor unit 3 stops operating. Each up-down wind deflector 35 is fixed to a rotating shaft (not shown), and each up-down wind deflector 35 rotates in the up-down direction to deflect the air blown out from the outlet 30g in the up-down direction.

[0098] When viewed from the upper and lower wind deflectors 35, a plurality of left and right wind deflectors 36 are provided on the upstream side of the outlet 30g (inside the indoor unit frame 30) to deflect the air blown out from the outlet 30g to the left and right directions. Each left and right wind deflector 36 is formed of a resin material and is fixed to a rotating shaft (not shown). The air blown out from the outlet 30g is deflected to the left and right directions by the left and right wind deflectors 36 rotating to the left and right directions.

[0099] A filter 38 for removing dust contained in the air taken into the indoor unit 3 is arranged on the upstream side of the indoor heat exchanger 31 in the ventilation path 30h (between the indoor heat exchanger 31 and the suction port 30f). The filter 38 is formed by weaving fibers made of a resin material into a mesh shape, for example. When the indoor air taken into the interior of the frame 30 of the indoor unit 3 from the suction port 30f passes through the filter 38, dust contained in the indoor air that is larger than the mesh of the filter 38 is captured by the filter 38.

[0100] <Structure of air conditioner and refrigerant circuit>

[0101] Next, use Figure 2 The refrigerant circuit of the air conditioner 1 formed by connecting the outdoor unit 2 and the indoor unit 3 with the refrigerant pipes, which is composed of the devices constituting the outdoor unit 2 and the indoor unit 3, is described in detail. As described above, the outdoor unit 2 and the indoor unit 3 are connected by the liquid pipe 4 and the gas pipe 5 as the refrigerant pipes. Specifically, the closing valve 25 of the outdoor unit 2 and the liquid pipe connection part 33 of the indoor unit 3 are connected by the liquid pipe 4. In addition, the closing valve 26 of the outdoor unit 2 and the gas pipe connection part 34 of the indoor unit 3 are connected by the gas pipe 5. As described above, the refrigerant circuit 10 of the air conditioner 1 is constructed.

[0102] <Structure of outdoor unit>

[0103] The outdoor unit 2 includes a compressor 21, a four-way valve 22, an outdoor heat exchanger 23, an outdoor fan 27, a closing valve 25 connected to a liquid pipe 4, a closing valve 26 connected to a gas pipe 5, an expansion valve 24, and an outdoor unit control unit 200. These devices except the outdoor fan 27 and the outdoor unit control unit 200 constitute an outdoor unit refrigerant circuit 10a that is a part of the refrigerant circuit 10 by interconnecting refrigerant pipes described in detail below.

[0104] The compressor 21 is a variable capacity compressor that can change the operating capacity by controlling the rotation speed through an inverter (not shown). The refrigerant discharge side of the compressor 21 is connected to the port a of the four-way valve 22 through the discharge pipe 61. In addition, the refrigerant suction side of the compressor 21 is connected to the port c of the four-way valve 22 through the suction pipe 66.

[0105] The four-way valve 22 is a valve for switching the direction of the refrigerant flow, and has four ports a, b, c, and d. As described above, port a is connected to the refrigerant discharge side of the compressor 21 through the discharge pipe 61. Port b is connected to a refrigerant inlet and outlet of the outdoor heat exchanger 23 through the refrigerant pipe 62. As described above, port c is connected to the refrigerant suction side of the compressor 21 through the suction pipe 66. Moreover, port d is connected to the closing valve 26 through the outdoor unit air pipe 64.

[0106] The outdoor heat exchanger 23 performs heat exchange between the refrigerant and the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 27 described later. As described above, one refrigerant inlet and outlet of the outdoor heat exchanger 23 is connected to the port b of the four-way valve 22 through the refrigerant piping 62, and the other refrigerant inlet and outlet is connected to the closing valve 25 through the outdoor unit liquid pipe 63.

[0107] The expansion valve 24 is, for example, an electronic expansion valve, and adjusts the amount of refrigerant flowing to the indoor unit 3 by adjusting its opening degree according to the cooling capacity and heating capacity requested by the indoor unit 3 .

[0108] The outdoor fan 27 is formed of a resin material and is arranged near the outdoor heat exchanger 23. The outdoor fan 27 is rotated by a fan motor (not shown), thereby taking in external air from an intake port (not shown) of the outdoor unit 2 into the interior of the outdoor unit 2, and exhausting the external air that has exchanged heat with the refrigerant in the outdoor heat exchanger 23 to the outside of the outdoor unit 2 from an outlet (not shown) of the outdoor unit 2.

[0109] In addition to the above-described devices, the outdoor unit 2 is also provided with the following three sensors. Figure 1 As shown in (A), a discharge temperature sensor 71 for detecting the temperature of the refrigerant discharged from the compressor 21 is provided on the discharge pipe 61. An outdoor heat exchange temperature sensor 72 for detecting the temperature of the outdoor heat exchanger 23 (hereinafter referred to as the outdoor heat exchange temperature) is provided in a substantially middle portion of the refrigerant path (not shown) of the outdoor heat exchanger 23. In addition, an outdoor air temperature sensor 73 for detecting the temperature of the external air flowing into the outdoor unit 2, that is, the outside air temperature, is provided near the suction port (not shown) of the outdoor unit 2.

[0110] The outdoor unit control unit 200 is mounted on a control substrate stored in an electrical component box (not shown) of the outdoor unit 2. Figure 2 As shown in FIG. 2 (B), the outdoor unit control unit 200 includes a CPU 210 , a storage unit 220 , a communication unit 230 , and a sensor input unit 240 .

[0111] The storage unit 220 is composed of a ROM or a RAM, and stores a control program from the outdoor unit 2, detection values ​​corresponding to detection signals of various sensors, control states of the compressor 21 and the outdoor fan 27, etc. The communication unit 230 is an interface for communicating with the indoor unit 3. The sensor input unit 240 takes in the detection results of various sensors of the outdoor unit 2 and outputs them to the CPU 210.

[0112] The CPU 210 takes in the detection results of the sensors of the outdoor unit 2 via the sensor input unit 240. In addition, the CPU 210 obtains the control signal sent from the indoor unit 3 via the communication unit 230. The CPU 210 performs drive control of the compressor 21 and the outdoor fan 27 based on the detection results and control signals taken in. In addition, the CPU 210 performs switching control of the four-way valve 22 based on the detection results and control signals taken in. In addition, the CPU 210 adjusts the opening of the expansion valve 24 based on the detection results and control signals taken in.

[0113] <Structure of indoor unit>

[0114] The indoor unit 3 includes a liquid pipe connection portion 33 to which the liquid pipe 4 is connected, a gas pipe connection portion 34 to which the gas pipe 5 is connected, and an indoor unit control unit 300, in addition to the indoor heat exchanger 31, the indoor fan 32, the vertical wind direction plate 35, the horizontal wind direction plate 36, and the filter 38 described above. Furthermore, the devices other than the indoor fan 32, the vertical wind direction plate 35, the horizontal wind direction plate 36, the filter 38, and the indoor unit control unit 300 constitute an indoor unit refrigerant circuit 10b that is a part of the refrigerant circuit 10 by mutually connecting the refrigerant pipes described in detail below.

[0115] The indoor heat exchanger 31 performs heat exchange between the refrigerant and the indoor air taken into the indoor unit 3 from the suction port 30f of the indoor unit 3 by the rotation of the indoor fan 32. One refrigerant inlet and outlet are connected to the liquid pipe connection part 33 through the indoor unit liquid pipe 67, and the other refrigerant inlet and outlet are connected to the gas pipe connection part 34 through the indoor unit gas pipe 68. The indoor heat exchanger 31 functions as an evaporator when the indoor unit 3 performs cooling operation, and functions as a condenser when the indoor unit 3 performs heating operation. In addition, at the liquid pipe connection part 33 and the gas pipe connection part 34, each refrigerant pipe is connected by welding or flaring nuts.

[0116] The indoor fan 32 is formed of a resin material and is arranged on the downstream side of the indoor heat exchanger 31 of the ventilation path 30h as described above. The indoor fan 32 is rotated by a fan motor (not shown) to take indoor air into the indoor unit 3 from the suction port 30f of the indoor unit 3 and blow the indoor air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 into the room from the blow-out port 30g of the indoor unit 3.

[0117] In addition to the above-described devices, the indoor unit 3 is provided with two sensors described below. An indoor heat exchange temperature sensor 74 for detecting the temperature of the indoor heat exchanger 31 (hereinafter referred to as the indoor heat exchange temperature) is provided approximately in the middle of the refrigerant path (not shown) of the indoor heat exchanger 31. Figure 1 As shown in FIG. 2(B) , an indoor temperature sensor 75 for detecting the temperature of air sucked into the indoor unit 3 from the suction port 30 f , that is, the indoor temperature, is provided between the suction port 30 f of the indoor unit 3 and the filter 38 .

[0118] The indoor unit control unit 300 is mounted on a control substrate stored in an electrical component box (not shown) of the indoor unit 3. Figure 2 As shown in FIG. 2 (B), the indoor unit control unit 300 includes a CPU 310 , a storage unit 320 , a communication unit 330 , and a sensor input unit 340 .

[0119] The storage unit 320 is composed of a ROM or a RAM, and stores control programs from the indoor unit 3, detection values ​​corresponding to detection signals of various sensors, control states of the indoor fan 32, etc. The communication unit 330 is an interface for communicating with the outdoor unit control unit 200 of the outdoor unit 2. The sensor input unit 340 takes in the detection results of the indoor heat exchange temperature sensor 74 and the indoor temperature sensor 75 of the indoor unit 3, and outputs them to the CPU 110.

[0120] The CPU 310 receives the detection results of the sensors of the indoor unit 3 via the sensor input unit 340. In addition, the CPU 310 receives an operation information signal including an operation mode (cooling operation / heating operation) and air volume, etc., transmitted from a remote controller (not shown) operated by a user via the communication unit 330. The CPU 310 controls the driving of the indoor fan 32, the up-and-down wind direction plate 35, and the left-and-right wind direction plate 36 based on the received detection results and operation information signal.

[0121] <Operation of Refrigerant Circuit>

[0122] Next, use Figure 2 (A) describes the flow of refrigerant in the refrigerant circuit 10 and the operation of each part of the air conditioner 1 in the present embodiment during air conditioning operation. In the following description, the case where the indoor unit 3 performs cooling operation is first described, and then the case where the indoor unit 3 performs heating operation is described. Figure 2 In (A), the solid arrows indicate the flow of the refrigerant during the cooling operation, and the dotted arrows indicate the flow of the refrigerant during the heating operation.

[0123] <Cooling Operation>

[0124] When the indoor unit 3 performs cooling operation, Figure 2 As shown in (A), the four-way valve 22 is switched to the state shown by the solid line, that is, the port a and the port b of the four-way valve 22 are switched to be connected, or the port c and the port d are connected. As a result, in the refrigerant circuit 10, the outdoor heat exchanger 23 functions as a condenser, and the indoor heat exchanger 31 functions as an evaporator, and the refrigerant circuit 10 becomes a refrigeration cycle in which the refrigerant circulates in the direction shown by the solid arrow.

[0125] In the state of the refrigerant circuit 10 as described above, the high-pressure refrigerant discharged from the compressor 21 flows through the discharge pipe 61 into the four-way valve 22, flows from the four-way valve 22 into the refrigerant pipe 62, and flows into the outdoor heat exchanger 23. The refrigerant flowing into the outdoor heat exchanger 23 exchanges heat with the outside air taken into the interior of the outdoor unit 2 by the rotation of the outdoor fan 27 and condenses. The refrigerant flowing out of the outdoor heat exchanger 23 to the outdoor unit liquid pipe 63 is decompressed when passing through the expansion valve 24 with an opening corresponding to the cooling capacity requested by the user in the indoor unit 3, and flows into the liquid pipe 4 through the closing valve 25.

[0126] The refrigerant flowing through the liquid pipe 4 and flowing into the indoor unit 3 via the liquid pipe connection portion 33 flows through the indoor unit liquid pipe 67 and flows into the indoor heat exchanger 31, and evaporates by exchanging heat with the indoor air taken into the ventilation path 30h of the indoor unit 3 from the suction port 30f by the rotation of the indoor fan 32. In this way, the indoor heat exchanger 31 functions as an evaporator, and the indoor air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 is blown out from the blow-out port 30g into the room, thereby cooling the room in which the indoor unit 3 is installed.

[0127] The refrigerant flowing out of the indoor heat exchanger 31 flows through the indoor unit air pipe 68 and flows into the air pipe 5 via the air pipe connection portion 34. The refrigerant flowing through the air pipe 5 and flowing into the outdoor unit 2 via the closing valve 26 flows through the outdoor unit air pipe 64, the four-way valve 22, and the suction pipe 66 in sequence, and is sucked into the compressor 21 and compressed again.

[0128] <Heating operation>

[0129] When the indoor unit 3 performs heating operation, Figure 2 As shown in (A), the four-way valve 22 is switched to the state shown by the dotted line, that is, the port a and the port d of the four-way valve 22 are switched to be connected, or the port b and the port c are connected. As a result, in the refrigerant circuit 10, the outdoor heat exchanger 23 functions as an evaporator, and the indoor heat exchanger 31 functions as a condenser, and the refrigerant circuit 10 becomes a heating cycle in which the refrigerant circulates in the direction shown by the dotted arrow.

[0130] In the state of the refrigerant circuit 10 as described above, the high-pressure refrigerant discharged from the compressor 21 flows through the discharge pipe 61 and flows into the four-way valve 22, flows from the four-way valve 22 into the outdoor unit gas pipe 64, and flows into the gas pipe 5 via the closing valve 26. The refrigerant flowing through the gas pipe 5 flows into the indoor unit 3 via the gas pipe connection portion 34.

[0131] The refrigerant flowing into the indoor unit 3 flows through the indoor unit air pipe 68 and flows into the indoor heat exchanger 31, and is condensed by exchanging heat with the indoor air taken into the ventilation path 30h of the indoor unit 3 from the suction port 30f by the rotation of the indoor fan 32. In this way, the indoor heat exchanger 31 functions as a condenser, and the indoor air that has exchanged heat with the refrigerant in the indoor heat exchanger 31 is blown out from the blow-out port 30g into the room, thereby heating the room where the indoor unit 3 is installed.

[0132] The refrigerant flowing out of the indoor heat exchanger 31 flows through the indoor unit liquid pipe 67 and flows into the liquid pipe 4 via the liquid pipe connection portion 33. The refrigerant flowing through the liquid pipe 4 and flowing into the outdoor unit 2 via the closing valve 25 flows through the outdoor unit liquid pipe 63 and is decompressed when passing through the expansion valve 24 whose opening degree corresponds to the heating capacity requested by the user in the indoor unit 3.

[0133] The refrigerant that passes through the expansion valve 24 and flows into the outdoor heat exchanger 23 evaporates by exchanging heat with the outside air taken into the outdoor unit 2 by the rotation of the outdoor fan 27. The refrigerant that flows out of the outdoor heat exchanger 23 to the refrigerant pipe 62 passes through the four-way valve 22 and the suction pipe 66, is sucked into the compressor 21, and is compressed again.

[0134] <Drive Control of Compressor, Outdoor Fan, and Indoor Fan during Heating Operation>

[0135] Next, use Figure 3 The flowchart shown in the figure details the drive control of the compressor 21, the outdoor fan 27, and the indoor fan 32 during the heating operation (hereinafter referred to as the heating operation control). Figure 3 In the figure, ST indicates a processing step, and the number after it indicates the step number.

[0136] In addition, the outdoor unit control unit 200 and the indoor unit control unit 300 constitute the control unit of the present invention. Figure 3 In the subsequent control and processing, the control unit is used as the control body of the air conditioner 1, and the outdoor unit control unit 200 (CPU210) and the indoor unit control unit 300 (CPU310) are appropriately used as the control body of each device of the outdoor unit 2 and the indoor unit 3.

[0137] If there is an instruction to start the heating operation according to the user's instruction, the control unit takes in the indoor temperature (hereinafter referred to as indoor temperature Ti) and reads out the set temperature (hereinafter referred to as set temperature Tp) (ST1). Specifically, the CPU 310 of the indoor unit control unit 300 periodically (for example, every 30 seconds) takes in the indoor temperature Ti detected by the sensor input unit 340 via the sensor input unit 340. In addition, the CPU 310 reads out the set temperature Tp set by the user's operation of a remote controller (not shown) and stored in the storage unit 320.

[0138] Next, the control unit calculates the temperature difference (hereinafter referred to as temperature difference ΔT) between the setting temperature Tp read out in ST1 and the taken-in indoor temperature Ti (ST2). Specifically, CPU 310 calculates temperature difference ΔT by subtracting indoor temperature Ti from setting temperature Tp.

[0139] Next, the control unit drives the compressor 21 at the rotation speed of the compressor 21 corresponding to the temperature difference ΔT calculated in ST2 (hereinafter referred to as the compressor rotation speed Rc) (ST3). Specifically, the CPU 310 transmits the compressor rotation speed Rc corresponding to the calculated temperature difference ΔT to the outdoor unit 2 via the communication unit 330. The CPU 210 of the outdoor unit control unit 200, which receives the compressor rotation speed Rc transmitted from the indoor unit 3 via the communication unit 230, drives the compressor 21 at the received compressor rotation speed Rc.

[0140] Next, the control unit sets the opening degree of the expansion valve 24 (hereinafter referred to as the expansion valve opening degree D) to an opening degree corresponding to the heating capacity requested by the user in the indoor unit 3 (ST4). Specifically, the CPU 310 adjusts the expansion valve opening degree D so that the discharge temperature of the compressor 21 detected by the discharge temperature sensor 71 during the heating operation becomes a predetermined target temperature.

[0141] Next, the control unit drives the outdoor fan 27 at the rotation speed of the outdoor fan 27 (hereinafter referred to as the outdoor fan rotation speed Rfo) corresponding to the compressor rotation speed Rc determined in ST3 (ST5). Specifically, the CPU 210 drives the outdoor fan 27 at the outdoor fan rotation speed Rfo corresponding to the compressor rotation speed Rc.

[0142] Next, the control unit determines whether the air volume of the conditioned air blown out from the outlet 30g of the indoor unit 3 is set to automatic by the user (ST6). If the air volume is set to automatic (ST6-Yes), the control unit drives the indoor fan 32 at the rotation speed of the indoor fan 32 corresponding to the temperature difference ΔT calculated in ST2 (hereinafter referred to as the indoor fan rotation speed Rfi) (ST7). In addition, if the air volume is not set to automatic (ST6-No), the control unit drives the indoor fan 32 at the indoor fan rotation speed Rfi corresponding to the air volume set by the user (ST8). Specifically, the CPU 310 drives the indoor fan 32 at the indoor fan rotation speed Rfi corresponding to either the temperature difference ΔT or the air volume set by the user.

[0143] Next, the control unit controls the up-down wind direction plate 35 and the left-right wind direction plate 36 to make the wind direction set by the user (ST9), and returns the process to ST1. Specifically, if the user's setting is "swing", the CPU 310 automatically rotates the up-down wind direction plate 35 up and down and the left-right wind direction plate 36 left and right. In addition, if the user's setting is a specified position, the up-down wind direction plate 35 and the left-right wind direction plate 36 are rotated to be at the position set by the user.

[0144] <Protection control during heating operation>

[0145] Next, use Figure 4 The following describes the protection control during heating operation in which the discharge pressure of the compressor 21 does not exceed the upper limit of the operating range during heating operation. Figure 4 In the figure, ST indicates a processing step, and the number after it indicates the step number.

[0146] First, the control unit takes in the temperature of the indoor heat exchanger 31 (hereinafter referred to as the indoor heat exchange temperature Tc) and the discharge temperature of the compressor 21 (hereinafter referred to as the discharge temperature Td) (ST11). Specifically, the CPU 310 periodically (for example, every 30 seconds) takes in the indoor heat exchange temperature Tc detected by the indoor heat exchange temperature sensor 74 via the sensor input unit 340. On the other hand, the CPU 210 periodically (for example, every 30 seconds) takes in the discharge temperature Td detected by the discharge temperature sensor 71 via the sensor input unit 240.

[0147] Next, the control unit determines whether the indoor heat exchange temperature Tc taken in ST11 is higher than a predetermined temperature (hereinafter referred to as the first threshold indoor heat exchange temperature Tch1) (ST12). Specifically, the CPU 310 reads the first threshold indoor heat exchange temperature Tch1 pre-stored in the storage unit 320, and compares it with the indoor heat exchange temperature Tc. Here, the first threshold indoor heat exchange temperature Tch1 is a temperature obtained by performing experiments in advance, etc., and is set to a temperature lower than the indoor heat exchange temperature Tc corresponding to the upper limit value of the use range of the discharge pressure of the compressor 21 by a predetermined temperature, for example, 55°C.

[0148] If the indoor heat exchange temperature Tc is above the first threshold indoor heat exchange temperature Tch1 (ST12-Yes), the control unit reduces the rotation speed of the compressor 21 by a predetermined compressor release rotation speed (hereinafter referred to as the compressor release rotation speed Rcr) every predetermined compressor release interval time (hereinafter referred to as the compressor release interval time tc) (ST16). Specifically, the CPU 310 sends a signal to the outdoor unit 2 via the communication unit 330 that the indoor heat exchange temperature Tc is higher than the first threshold indoor heat exchange temperature Tch1. The CPU 210 that receives the signal via the communication unit 230 controls the compressor 21 to reduce the compressor release rotation speed Rcr from the current compressor rotation speed Rc every compressor release interval time tc. Here, the compressor release interval time tc and the compressor release rotation speed Rcr are values ​​that have been previously tested and confirmed to have an effect of reducing the indoor heat exchange temperature Tc. For example, the compressor release interval time tc is 60 seconds and the compressor release rotation speed Rcr is 2 rps.

[0149] After completing the process of ST16, the control unit takes in the indoor heat exchange temperature Tc (ST17), and determines whether the taken-in indoor heat exchange temperature Tc is greater than the first threshold indoor heat exchange temperature Tch1 (ST18). Specifically, the CPU 310 takes in the indoor heat exchange temperature Tc, and determines whether the taken-in indoor heat exchange temperature Tc is greater than the first threshold indoor heat exchange temperature Tch1.

[0150] If the input indoor heat exchange temperature Tc is not above the first threshold indoor heat exchange temperature Tch1 (ST18-No), the control unit returns the process to ST11. If the input indoor heat exchange temperature Tc is above the first threshold indoor heat exchange temperature Tch1 (ST18-Yes), the control unit stops the heating operation (ST19) and ends the protection control during the heating operation. Specifically, if the input indoor heat exchange temperature Tc is above the first threshold indoor heat exchange temperature Tch1, the CPU 310 stops the indoor fan 32, and at the same time, sends a signal indicating that the input indoor heat exchange temperature Tc is above the first threshold indoor heat exchange temperature Tch1 to the outdoor unit 2 via the communication unit 330. The CPU 210 that receives the signal via the communication unit 230 stops the compressor 21 and the outdoor fan 27.

[0151] In ST12, if the indoor heat exchange temperature Tc is not higher than the first threshold indoor heat exchange temperature Tch1 (ST12-No), the control unit determines whether the discharge temperature Td detected in ST11 is higher than a prescribed first threshold discharge temperature (hereinafter referred to as the first threshold discharge temperature Tdh1) and lower than a prescribed second threshold discharge temperature (hereinafter referred to as the second threshold discharge temperature Tdh2) higher than the first threshold discharge temperature Tdh1 (ST13). Specifically, the CPU 210 periodically (for example, every 30 seconds) takes in the discharge temperature Td detected by the discharge temperature sensor 71 via the sensor input unit 240, and determines whether the taken-in discharge temperature Td is higher than the first threshold discharge temperature Tdh1 and lower than the second threshold discharge temperature Tdh2.

[0152] Here, the first threshold discharge temperature Tdh1 and the second threshold discharge temperature Tdh2 are temperatures obtained by conducting experiments in advance and stored in the storage unit 220, and are temperatures that are a specified temperature lower than the discharge temperature Td corresponding to the upper limit value of the use range of the discharge pressure of the above-mentioned compressor 21. For example, the first threshold discharge temperature Tdh1 is 105°C, and the second threshold discharge temperature Tdh2 is 115°C.

[0153] If the input discharge temperature Td is greater than the first threshold discharge temperature Tdh1 and less than the second threshold discharge temperature Tdh2 (ST13-Yes), the control unit reduces the speed of the compressor 21 by the compressor release speed Rcr each time according to the compressor release interval time tc (ST15), and returns the process to ST11. In addition, the process of ST15 is the same as the process of ST16 described above, so detailed description is omitted. In addition, in the processes of ST15 and ST16, by reducing the compressor release speed Rcr each time, when the compressor speed Rc is reduced to the lower limit speed of the use range, the compressor speed Rc is maintained at the lower limit speed when the processes of ST15 and ST16 are performed.

[0154] In ST13, if the input discharge temperature Td is not equal to or higher than the first threshold discharge temperature Tdh1 and lower than the second threshold discharge temperature Tdh2 (ST13-No), the control unit determines whether the input discharge temperature Td is equal to or higher than the second threshold discharge temperature Tdh2 (ST14). Specifically, the CPU 210 determines whether the input discharge temperature Td is equal to or higher than the second threshold discharge temperature Tdh2.

[0155] If the input discharge temperature Td is equal to or higher than the second threshold discharge temperature Tdh2 (ST14-Yes), the control unit causes the process to proceed to ST19. If the input discharge temperature Td is not equal to or higher than the second threshold discharge temperature Tdh2 (ST14-No), that is, if the input discharge temperature Td is lower than the first threshold discharge temperature Tdh1, the control unit causes the process to return to ST11.

[0156] <Indoor heat exchange heating operation>

[0157] Next, use Figures 5 to 11 , explaining the indoor heat exchange heating operation of the present invention. Here, the so-called indoor heat exchange heating operation is an operation performed for the following purpose, setting the refrigerant circuit 10 of the air conditioner 1 to the same state as during the heating operation, and raising the temperature of the indoor heat exchanger 31 to a temperature higher than the temperature during the heating operation (about 40°C), killing molds or bacteria to reduce their number. In addition, in the present embodiment, a button indicating the start of the indoor heat exchange heating operation is provided on the remote controller (not shown) for operating the indoor unit 3, and the indoor heat exchange heating operation will be executed as long as the user operates the button, but the indoor heat exchange heating operation can also be automatically executed at the end of the cooling operation and the dehumidification operation. In addition, it is also possible to use the air conditioner 1 to determine the best time and perform the indoor heat exchange heating operation, just like a human body detection sensor is provided in the indoor unit 3, and the indoor heat exchange heating operation is performed when the human body detection sensor detects that the user is not in the room.

[0158] The applicant has conducted experiments and found that when performing the above-mentioned indoor heat exchange heating operation, the number of mold and bacteria can be greatly reduced by maintaining the indoor heat exchange temperature Tc at 55°C or above for 10 minutes. Figure 5 The obtained insights are explained.

[0159] Figure 5 The graph shown shows the time change of the number of mold and bacteria when the indoor heat exchange temperature Tc is maintained at a constant temperature in a state where dew condensation water exists in the indoor heat exchanger 31 . Figure 5 (A) is a graph regarding Cladosporium (hereinafter referred to as "mold"), which is a type of mold (black mold) that looks very black. Figure 5 The horizontal axis of the graph (A) is the time for maintaining the indoor heat exchange temperature Tc at 40°C, 45°C and 50°C, i.e., the heating time (unit: minutes), and the vertical axis is the residual rate of mold (the number of mold colonies) when the heating time is set to 0 minutes (before heating) as 100. Figure 5 The residual rate of mold in (A). Unit: %).

[0160] observe Figure 5 In (A), when the indoor heat exchange temperature Tc is set to 40°C, the number of molds is almost unchanged even when the heating time reaches 10 minutes, and the mold remaining rate after 10 minutes is approximately 100%. In contrast, when the indoor heat exchange temperature Tc is set to 45°C or 50°C, the mold remaining rate is less than 10% at any indoor heat exchange temperature Tc when the heating time reaches 5 minutes. In particular, when the indoor heat exchange temperature Tc is set to 50°C, the mold remaining rate is less than 1% at the time when the heating time reaches 5 minutes, and the number of molds is greatly reduced in a short time.

[0161] on the other hand, Figure 5 (B) is a graph regarding Escherichia coli, which is a type of bacteria. Figure 5 The horizontal axis of the graph (B) is the time for maintaining the indoor heat exchange temperature Tc at 40°C, 45°C, 50°C, and 55°C, i.e., the heating time (unit: minutes), and the vertical axis is the coliform survival rate (unit: minutes) when the number of coliform bacteria at the heating time of 0 minutes (before heating) is set to 100. Figure 5 (B) is the bacterial survival rate. Unit: %).

[0162] observe Figure 5In (B), when the indoor heat exchange temperature Tc is lower than 50°C, even if the heating time reaches 10 minutes, the bacterial survival rate is not lower than 50%, and it cannot be said that the number of bacteria has been significantly reduced. In contrast, when the indoor heat exchange temperature Tc is set to 55°C, the bacterial survival rate is less than 10% when the heating time reaches 4 minutes, and the bacterial survival rate is approximately 1% when the heating time reaches 5 minutes. If the heating time is further extended to 10 minutes, the bacterial survival rate is lower than 1%. That is, by maintaining the indoor heat exchange temperature Tc at 55°C for 10 minutes, the number of bacteria can be greatly reduced.

[0163] From the above description Figure 5 From the various graphs of FIG. 1 , in order to significantly reduce the residual rate of mold and bacteria existing in the indoor heat exchanger 31, in the state where condensation water exists in the indoor heat exchanger 31, for example, in the state where condensation water generated in the indoor heat exchanger 31 during the cooling operation of the air conditioner 1 still remains after the cooling operation ends, it is preferred to set the indoor heat exchange temperature Tc to be above 55°C and keep this state for 10 minutes. This is because the entire surface of mold and bacteria is covered with condensation water, so the heat acting on the mold and bacteria from the condensation water is greater than the heat acting on the mold and bacteria only from the surface of the indoor heat exchanger 31 when there is no condensation water.

[0164] In addition, for the condensed water generated in the indoor heat exchanger 31 when the air conditioner 1 is in cooling operation, even if the drying operation is performed after the cooling operation to drive the indoor fan 32 to make the air pass through the indoor heat exchanger 31 to evaporate the condensed water, the V-shaped bent portion 30n of the indoor heat exchanger 31 and the air-difficult-to-pass portion near the drain pan 30m cannot be dried. In this way, even in the portion where the condensed water is not dried and stays for a long time, as long as the indoor heat exchange heating operation of this embodiment is performed, the condensed water staying in the above-mentioned portion where the air is difficult to pass can reach 55°C or more, so the residual rate of mold and bacteria that grow in these portions can be greatly reduced.

[0165] <Indoor fan control table and outdoor fan control table>

[0166] Next, use Figure 6 A table used when the indoor heat exchange heating operation is performed and used for controlling the indoor fan 32 and the outdoor fan 27 during the indoor heat exchange heating operation will be described.

[0167] <Indoor fan control table>

[0168] First of all, Figure 6The indoor fan control table 400 shown in (A) is described. The indoor fan control table 400 is obtained by conducting experiments in advance, etc., and is stored in the storage unit 320 of the indoor unit control unit 300. As is known to all, when the indoor heat exchanger 31 functions as a condenser during the indoor heat exchange heating operation, the indoor fan control table 400 controls the indoor fan 32 based on the indoor fan control table 400 so that the indoor heat exchange temperature Tc is maintained in the range of 55°C to 57°C.

[0169] In the indoor fan control table 400, the indoor fan speed Rfi (unit: rpm) is determined according to the indoor heat exchange temperature Tc (unit: °C) and the time when the indoor heat exchange temperature Tc rises / maintains / decreases. Figure 6 (A) "When Tc rises") refers to the situation where the indoor heat exchange temperature Tc detected later is higher than the indoor heat exchange temperature Tc detected earlier using two indoor heat exchange temperatures Tc detected at intervals. In addition, when the indoor heat exchange temperature Tc is maintained (at Figure 6 (A) "Tc is maintained" refers to the situation where the indoor heat exchange temperature Tc detected previously and the indoor heat exchange temperature Tc detected later are the same. In addition, when the indoor heat exchange temperature Tc decreases ( Figure 6 The "when Tc decreases" in (A) refers to a situation where, using two indoor heat exchange temperatures Tc detected at intervals of time, the later detected indoor heat exchange temperature Tc is lower than the previously detected indoor heat exchange temperature Tc.

[0170] Specifically, the indoor fan speed Rfi during "Tc rises" is set to a speed obtained by adding 70 rpm to the current indoor fan speed Rfi when the indoor heat exchange temperature Tc is 57°C or higher. When the indoor heat exchange temperature Tc is 55°C or higher and lower than 57°C, the current indoor fan speed Rfi is not changed. When the indoor heat exchange temperature Tc is 53°C or higher and lower than 55°C, and when the indoor heat exchange temperature Tc is lower than 53°C, the speed is set to a speed obtained by subtracting 10 rpm from the current indoor fan speed Rfi.

[0171] When the indoor heat exchange temperature Tc rises and the indoor heat exchange temperature Tc is lower than 53°C, or when the indoor heat exchange temperature Tc is higher than 53°C and lower than 55°C, the indoor fan speed Rfi is reduced by 10 rpm each time the indoor heat exchange temperature Tc is detected (for example, every 30 seconds). As a result, the amount of air flowing through the indoor heat exchanger 31 decreases, and the indoor heat exchange temperature Tc quickly reaches 55°C or higher.

[0172] When the indoor heat exchange temperature Tc rises and the indoor heat exchange temperature Tc is 55° C. or higher and lower than 57° C., the indoor fan speed Rfi is not changed. As a result, the amount of air flowing through the indoor heat exchanger 31 is not changed, and the indoor heat exchange temperature Tc is maintained in the range of 55° C. or higher and lower than 57° C. Moreover, when the indoor heat exchange temperature Tc is 57° C. or higher, the indoor fan speed Rfi is increased by 70 rpm each time to increase the amount of air flowing to the indoor heat exchanger 31, so that the indoor heat exchange temperature Tc does not reach 59° C. or higher.

[0173] Next, when the indoor heat exchange temperature Tc is above 57°C, the indoor fan speed Rfi for "Tc maintenance" is set to a speed obtained by adding 50 rpm to the current indoor fan speed Rfi. When the indoor heat exchange temperature Tc is above 55°C and below 57°C, the current indoor fan speed Rfi is not changed. When the indoor heat exchange temperature Tc is above 53°C and below 55°C, it is set to a speed obtained by subtracting 30 rpm from the current indoor fan speed Rfi. When the indoor heat exchange temperature Tc is below 53°C, it is set to a speed obtained by subtracting 40 rpm from the current indoor fan speed Rfi.

[0174] When the indoor heat exchange temperature Tc is lower than 53°C when the indoor heat exchange temperature Tc does not change, the indoor fan speed Rfi is reduced by 40 rpm each time the indoor heat exchange temperature Tc is detected (for example, every 30 seconds). In addition, when the indoor heat exchange temperature Tc is above 53°C and below 55°C, the indoor fan speed Rfi is reduced by 30 rpm each time the indoor heat exchange temperature Tc is detected. As a result, the amount of air flowing through the indoor heat exchanger 31 decreases, and the indoor heat exchange temperature Tc quickly reaches above 55°C. In addition, it is considered that the indoor heat exchange temperature Tc is difficult to rise in the "Tc maintenance" state compared to the "Tc rise" state, so the speed reduced from the indoor fan speed Rfi is increased so that the indoor fan speed Rfi is lower than the "Tc rise" state even at the same indoor heat exchange temperature Tc.

[0175] When the indoor heat exchange temperature Tc is 55°C or more and less than 57°C when the indoor heat exchange temperature Tc does not change, the indoor fan speed Rfi is not changed. As a result, the amount of air flowing through the indoor heat exchanger 31 does not change, and the indoor heat exchange temperature Tc is maintained in the range of 55°C or more and less than 57°C. Moreover, when the indoor heat exchange temperature Tc is 57°C or more, the indoor fan speed Rfi is increased by 50 rpm each time to increase the amount of air flowing through the indoor heat exchanger 31, thereby, the indoor heat exchange temperature Tc does not reach 59°C or more. In addition, it is considered that the indoor heat exchange temperature Tc is difficult to rise in the "Tc maintenance" state compared to the "Tc rise" state, so the speed added to the indoor fan speed Rfi is reduced so that even if the indoor heat exchange temperature Tc is the same, the indoor fan speed Rfi is lower than the "Tc rise" state.

[0176] Furthermore, regarding the indoor fan speed Rfi when "Tc decreases", when the indoor heat exchange temperature Tc is 57°C or higher, and when the indoor heat exchange temperature Tc is 55°C or higher and lower than 57°C, the current indoor fan speed Rfi is not changed. When the indoor heat exchange temperature Tc is 53°C or higher and lower than 55°C, and when the indoor heat exchange temperature Tc is lower than 53°C, the speed is set to a speed obtained by subtracting 40 rpm from the current indoor fan speed Rfi.

[0177] When the indoor heat exchange temperature Tc is lower than 53°C when the indoor heat exchange temperature Tc is decreasing, or when the indoor heat exchange temperature Tc is higher than 53°C and lower than 55°C, the indoor fan speed Rfi is reduced by 40 rpm each time the indoor heat exchange temperature Tc is detected (for example, every 30 seconds), thereby reducing the amount of air flowing through the indoor heat exchanger 31. Thus, the amount of air flowing through the indoor heat exchanger 31 is reduced, so that the indoor heat exchange temperature Tc quickly reaches 55°C or higher. Since "when Tc decreases" is in a state where the indoor heat exchange temperature Tc decreases, the speed subtracted from the indoor fan speed Rfi is increased, so that even at the same indoor heat exchange temperature Tc, the indoor fan speed Rfi is further reduced than "when Tc is maintained".

[0178] When the indoor heat exchange temperature Tc is lowered and the indoor heat exchange temperature Tc is higher than 55°C and lower than 57°C, or when the indoor heat exchange temperature Tc is higher than 57°C, the indoor fan speed Rfi is not changed. As a result, the amount of air flowing through the indoor heat exchanger 31 remains unchanged, and the indoor heat exchange temperature Tc is maintained in the range of higher than 55°C and lower than 57°C. In addition, it is considered that the indoor heat exchange temperature Tc is in a state that is difficult to rise when "Tc is lowered" compared to "Tc is maintained", so even if the indoor fan speed Rfi is not changed when the indoor heat exchange temperature Tc is higher than 55°C, the indoor heat exchange temperature Tc will not reach 59°C or higher.

[0179] In addition, when the indoor fan speed Rfi is increased or decreased using the indoor fan control table 400 described above, the indoor fan speed Rfi is increased or decreased between the upper limit speed and the lower limit speed (equivalent to the indoor fan minimum speed Rfim described later) of the indoor fan speed Rfi. Here, the upper limit speed is, for example, 900 rpm, and the lower limit speed is, for example, 300 rpm. If the indoor fan speed Rfi is increased by the speed determined by the indoor fan control table 400 each time and reaches 900 rpm, even if the indoor fan speed Rfi is increased thereafter, the indoor fan speed Rfi is maintained at 900 rpm. In addition, if the indoor fan speed Rfi is reduced by the speed determined by the indoor fan control table 400 each time and reaches 300 rpm, even if the indoor fan speed Rfi is reduced thereafter, the indoor fan speed Rfi is maintained at 300 rpm.

[0180] In addition, the above-mentioned lower limit speed of 300 rpm in the indoor heat exchange heating operation is set to a speed lower than the lower limit speed (e.g., 420 rpm) of the indoor fan 32 in the heating operation. This is because, in the indoor heat exchange heating operation, by reducing the speed of the indoor fan 32 as much as possible, the amount of air flowing through the indoor heat exchanger 31 is reduced, thereby rapidly increasing the indoor heat exchange temperature Tc.

[0181] <Outdoor fan control table>

[0182] Next, Figure 6 The outdoor fan control table 500 shown in (B) is described. The outdoor fan control table 500 is obtained by performing experiments in advance and is stored in the storage unit 220 of the outdoor unit control unit 200. As is known to all, in the outdoor fan control table 500, when the indoor heat exchange heating operation is performed based on the indoor fan control table 400 to control the indoor fan 32 so as to maintain the indoor heat exchange temperature Tc at 55°C to 57°C, the discharge pressure of the compressor 21 can be controlled not to exceed the upper limit of the use range by controlling the outdoor fan 27 based on the outdoor fan control table 500.

[0183] In the outdoor fan control table 500, the rotation speed of the outdoor fan (unit: rpm. Hereinafter recorded as the outdoor fan rotation speed Rfo) is determined based on the external air temperature (unit: °C. Hereinafter recorded as the external air temperature To) detected by the external air temperature sensor 73 and the indoor temperature Ti (unit: °C). Specifically, when the external air temperature To is above 24°C, the outdoor fan rotation speed Rfo is 0 rpm regardless of the indoor temperature Ti. In addition, when the external air temperature To is above 16°C and below 24°C, if the indoor temperature Ti is above 27°C, the outdoor fan rotation speed Rfo is 0 rpm, and if the indoor temperature Ti is below 27°C, the outdoor fan rotation speed Rfo is 190 rpm. Moreover, when the external air temperature To is below 16°C, the outdoor fan rotation speed Rfo is set to the same control as during heating operation, that is, the rotation speed corresponding to the compressor rotation speed Rc.

[0184] When the outside air temperature To is 24°C or higher, the evaporation pressure of the outdoor heat exchanger 23, which functions as an evaporator during the indoor heat exchange heating operation, becomes higher than when the outside air temperature To is lower than 24°C. When the evaporation pressure becomes higher, the condensation pressure of the indoor heat exchanger 31, which functions as a condenser, also becomes higher, so that the discharge pressure of the compressor 21 becomes higher and may exceed the upper limit of the use range. Therefore, when the outside air temperature To is 24°C or higher, regardless of the indoor temperature Ti, the evaporation capacity of the outdoor heat exchanger 23 is reduced by making the outdoor fan rotation speed Rfo 0 rpm, that is, stopping it, so as not to increase the evaporation pressure.

[0185] When the outside air temperature To is 16°C or more and less than 24°C and the indoor temperature Ti is 27°C or more, the condensing capacity of the indoor heat exchanger 31 acting as a condenser is reduced and the condensing pressure becomes higher than when the indoor temperature Ti is less than 27°C. At this time, if the evaporation capacity in the outdoor heat exchanger 23 is increased by driving the outdoor fan 27 and the evaporation pressure is increased, the condensing pressure that has been increased will be higher, so the discharge pressure of the compressor 21 is also increased, and there is a possibility that it exceeds the upper limit of the use range. Therefore, even if the outside air temperature To is 16°C or more and less than 24°C and the indoor temperature Ti is 27°C or more, the evaporation capacity of the outdoor heat exchanger 23 is reduced by making the outdoor fan rotation speed Rfo 0 rpm, that is, stopping it, so as not to increase the evaporation pressure.

[0186] On the other hand, when the outside air temperature To is 16°C or more and less than 24°C, and the indoor temperature Ti is less than 27°C, the discharge pressure of the compressor 21 is less likely to exceed the upper limit of the use range even if the outdoor fan 27 is driven because the condensation pressure is lower than when the indoor temperature Ti is 27°C or more. Therefore, when the outside air temperature To is 16°C or more and less than 24°C, and the indoor temperature Ti is less than 27°C, the outdoor fan speed Rfo is driven at a speed at which the discharge pressure of the compressor 21 does not exceed the upper limit of the use range due to the increase in the evaporation pressure, for example, at a speed of 190 rpm in the present embodiment. Thus, while preventing the discharge pressure of the compressor 21 from excessively increasing, the evaporation pressure in the outdoor heat exchanger 23 is increased, and the condensation temperature in the indoor heat exchanger 31, that is, the indoor heat exchange temperature Tc, is rapidly increased.

[0187] In addition, when the outside air temperature To is 16°C or more and less than 24°C and the indoor temperature Ti is less than 27°C during the above-mentioned indoor heat exchange heating operation, the outdoor fan speed Rfo, i.e., 190 rpm, is set to a speed lower than the lower limit speed (e.g., 500 rpm) of the outdoor fan 27 during the heating operation. This is because, considering that the discharge pressure of the compressor 21 is likely to exceed the upper limit value of the use range due to the increase in the indoor heat exchange temperature Tc during the indoor heat exchange heating operation to a temperature higher than that during the heating operation, the amount of air flowing through the outdoor heat exchanger 23 that functions as an evaporator during the indoor heat exchange heating operation is reduced compared to that during the heating operation, the evaporation pressure in the outdoor heat exchanger 23 is suppressed from rising, thereby suppressing an excessive increase in the discharge pressure of the compressor 21.

[0188] When the outside air temperature To is lower than 16°C, the evaporation pressure in the outdoor heat exchanger 23 is less likely to rise even if the outdoor fan 27 is driven, compared with the case where the outside air temperature To is higher than 16°C. Therefore, when the outside air temperature To is lower than 16°C, regardless of the indoor temperature Ti, the outdoor fan speed Rfo is set to the same control as during the heating operation, that is, the speed corresponding to the compressor speed Rc. As a result, the evaporation pressure in the outdoor heat exchanger 23 is increased, so that the condensation temperature in the indoor heat exchanger 31, that is, the indoor heat exchange temperature Tc, is rapidly increased.

[0189] <Indoor heat exchange heating operation control>

[0190] Next, use Figure 7 to Figure 10 The flow of processing related to the indoor heat exchange heating operation will be described. Figure 7 This is a main routine of processing performed by the control unit of the air conditioner 1 during the indoor heat exchange heating operation. Figure 8This is a subroutine for processing performed by the control unit during indoor heat exchange heating operation, and shows the flow of processing related to pre-heating operation control performed for the purpose of suppressing the generation of condensation water inside the indoor unit 3 before heating the indoor heat exchanger 31.

[0191] Fig. 9 It is a subroutine that the control unit performs during indoor heat exchange heating operation. Figure 6 The flow of processing related to indoor fan control during temperature maintenance is performed for the purpose of maintaining the indoor heat exchange temperature Tc in the range of 55° C. to 57° C. according to the indoor fan control table 400 shown in (A). Fig.10 It is a subroutine that the control unit performs during indoor heat exchange heating operation. Figure 6 The outdoor fan control table 500 shown in (B) shows the flow of processing related to the temperature-maintaining outdoor fan control performed when the indoor heat exchange temperature Tc is maintained in the range of 55°C to 57°C.

[0192] exist Figure 7 to Figure 10 In each flowchart of , ST represents a processing step, and the number after that represents the step number. Figure 7 and Fig. 9 The recorded Tc1 to Tc4 (hereinafter referred to as the first indoor heat exchange temperature Tc1 to the fourth indoor heat exchange temperature Tc4), the second indoor heat exchange temperature Tc2 to the fourth indoor heat exchange temperature Tc4 correspond to the indoor heat exchange temperature Tc recorded in the indoor fan control table 400, the second indoor heat exchange temperature Tc2 is 53°C, the third indoor heat exchange temperature Tc3 is 55°C, and the fourth indoor heat exchange temperature Tc4 is 57°C. In addition, the first indoor heat exchange temperature Tc1 is the temperature for starting the temperature maintenance operation described later, and is a temperature lower than the second indoor heat exchange temperature Tc2 by a predetermined temperature, for example, 50°C. In addition, the third indoor heat exchange temperature Tc3 is the first temperature of the present invention, the fourth indoor heat exchange temperature Tc4 is the second temperature of the present invention, and the first indoor heat exchange temperature Tc1 is the third temperature of the present invention.

[0193] <Main program: Indoor heat exchange heating operation control>

[0194] First, use Figure 7 The processing related to the indoor heat exchange heating operation control is described. If the user receives an instruction to execute the indoor heat exchange heating operation, or the air conditioner 1 ends the cooling operation, the control unit first executes the pre-heating operation control (ST41) which is a subroutine of the indoor heat exchange heating operation control. The pre-heating operation control will be described later.

[0195] Next, the control unit drives the compressor 21 at a predetermined minimum speed (hereinafter referred to as the compressor minimum speed Rcm) (ST42). Specifically, the CPU 210 of the outdoor unit control unit 200 reads the compressor minimum speed Rcm pre-stored in the storage unit 220, and drives the compressor 21 at the read compressor minimum speed Rcm. Here, as is well known, the compressor minimum speed Rcm is obtained in advance by conducting experiments, etc., and is a speed at which the discharge pressure of the compressor 21 does not exceed the upper limit of the use range even when the indoor heat exchange temperature Tc is set to a higher temperature than that during the normal heating operation during the indoor heat exchange heating operation. In addition, the compressor minimum speed Rcm is, for example, 30 rps.

[0196] Next, the control unit sets the expansion valve 24 to a predetermined opening (hereinafter referred to as the predetermined expansion valve opening Dp) (ST43). Specifically, the CPU 210 of the outdoor unit control unit 200 reads the predetermined expansion valve opening Dp pre-stored in the storage unit 220, and applies a drive pulse corresponding to the predetermined expansion valve opening Dp to the stepping motor (not shown) of the expansion valve 24 in such a manner that the expansion valve opening D becomes the read predetermined expansion valve opening Dp. Here, the predetermined expansion valve opening Dp is obtained in advance by performing experiments, etc., and is an opening at which the amount of refrigerant required to control the indoor heat exchange temperature Tc to a temperature in the range of 55°C or more and less than 57°C by controlling the indoor fan 32 alone when the indoor heat exchange heating operation of the present invention is performed by the air conditioner 1, flows through the indoor heat exchanger 31. In addition, the predetermined expansion valve opening Dp is, for example, 200 pulses when expressed by the number of drive pulses applied to the expansion valve 24.

[0197] Next, the control unit sets the outdoor fan speed Rfo to a speed corresponding to the compressor speed Rc (ST44). Specifically, the CPU 210 drives the outdoor fan 27 at the outdoor fan speed Rfo corresponding to the compressor speed Rc. In addition, at the time of performing the processing of ST43, the outdoor fan 27 has been driven by the pre-heating operation control described later. Therefore, in ST43, the outdoor fan speed Rfo is changed to a speed corresponding to the compressor speed Rc, and the outdoor fan speed Rfo at this time is, for example, 500 rpm.

[0198] Next, the control unit sets the indoor fan 32 to a predetermined rotation speed (hereinafter referred to as the indoor fan initial rotation speed Rfip) (ST45). Specifically, the CPU 310 of the indoor unit control unit 300 reads the indoor fan initial rotation speed Rfip pre-stored in the storage unit 320, and drives the indoor fan 32 as the indoor fan initial rotation speed Rfip of the indoor fan rotation speed Rfi. Here, the indoor fan initial rotation speed Rfip is obtained in advance by performing experiments, etc., and is a rotation speed that can prevent the indoor heat exchange temperature Tc from rising rapidly due to the small amount of indoor air supplied to the indoor heat exchanger 31 by the rotation of the indoor fan 32, and prevent the indoor heat exchange temperature Tc from being stopped by the protection control during the indoor heat exchange heating operation described later, and at the same time, the indoor heat exchange temperature Tc can be raised as soon as possible. In addition, the indoor fan initial rotation speed Rfip is, for example, 600 rpm. In addition, at the time of performing the processing of ST44, since the indoor fan 32 has been driven by the pre-heating operation control described later, the indoor fan rotation speed Rfi is changed to the indoor fan initial rotation speed Rfip in ST44.

[0199] Next, the control unit sets the up-down wind direction plate 35 to a horizontal position (ST46). Specifically, the CPU 310 rotates the up-down wind direction plate 35 to a horizontal position. If the up-down wind direction plate 35 is in a horizontal position, a portion of the air heated in the indoor heat exchanger 31 and blown out from the blow-out port 30g can be sucked into the suction port 30f. Therefore, compared with the case where the up-down wind direction plate 35 is in a position other than a horizontal position, the indoor heat exchange temperature Tc rises rapidly.

[0200] Next, the control unit starts the measurement of the timer 1 (ST47). Specifically, the CPU 310 has a timer measurement function, and the CPU 310 starts the measurement of the timer 1. In addition, the timer measurement function can be provided in the CPU 210, and can also be provided outside the CPU 210 and the CPU 310. Next, the control unit takes in the indoor heat exchange temperature Tc (ST48). Specifically, the CPU 310 takes in the indoor heat exchange temperature Tc detected by the indoor heat exchange temperature sensor 74 regularly (for example, every 30 seconds) via the sensor input unit 340.

[0201] Next, the control unit determines whether the indoor heat exchange temperature Tc input in ST48 is lower than the first indoor heat exchange temperature Tc1 (ST49). Specifically, the CPU 310 reads the first indoor heat exchange temperature Tc1 from the storage unit 320 and compares it with the input indoor heat exchange temperature Tc.

[0202] If the acquired indoor heat exchange temperature Tc is lower than the first indoor heat exchange temperature Tc1 (ST49-Yes), the control unit determines whether a predetermined time (hereinafter referred to as the first predetermined time tp1) has passed since the measurement of the timer 1 was started in ST47 (ST58). Specifically, the CPU 310 determines whether the first predetermined time tp1 has passed since the measurement of the timer 1 was started in ST47. Here, the first predetermined time tp1 is predetermined and stored in the storage unit 320, for example, 10 minutes.

[0203] If the first predetermined time tp1 has passed (ST58-Yes), the control unit resets the timer 1 (ST61) to terminate the indoor unit heat exchange heating operation control. Specifically, the CPU 310 resets the timer 1 and stops the indoor fan 32. In addition, the CPU 210 sends a signal including a message for terminating the indoor unit heat exchange heating operation control to the outdoor unit 2 via the communication unit 330. The CPU 210 receives the signal via the communication unit 230 and stops the compressor 21 and the outdoor fan 27.

[0204] If the first prescribed time tp1 has not passed (ST58-No), the control unit determines whether the current indoor fan speed Rfi is a prescribed minimum speed (hereinafter referred to as the indoor fan minimum speed Rfim) (ST59). Specifically, the CPU 310 reads the indoor fan minimum speed Rfim pre-stored in the storage unit 320 and compares it with the current indoor fan speed Rfi. Here, the indoor fan minimum speed Rfim is the lower limit speed of the use range of the indoor fan 32, for example, 300 rpm.

[0205] If the current indoor fan speed Rfi is the indoor fan minimum speed Rfim (ST59-Yes), the control unit maintains the indoor fan minimum speed Rfim (ST60), that is, continues to drive the indoor fan 32 at the indoor fan minimum speed Rfim, and returns the process to ST48. Specifically, the CPU 310 continues to drive the indoor fan 32 at the indoor fan minimum speed Rfim.

[0206] On the other hand, if the current indoor fan speed Rfi is not the indoor fan minimum speed Rfim (ST59-No), the control unit reduces the indoor fan speed Rfi by a predetermined indoor fan release speed (hereinafter referred to as indoor fan release speed Rfir) every predetermined indoor fan release interval (hereinafter referred to as indoor fan release interval tfi) (ST62), and returns the process to ST48. Specifically, the CPU 310 reduces the indoor fan release speed Rfi by the indoor fan release speed Rfir every indoor fan release interval tfi. In addition, the indoor fan release interval tfi and the indoor fan release speed Rfir are determined in advance by performing experiments, etc., and it can be confirmed that the indoor heat exchange temperature Tc rises while suppressing a sharp rise in the indoor heat exchange temperature Tc and becoming a protection stop due to the protection control during the indoor heat exchange heating operation described later. The indoor fan release interval tfi is, for example, 60 seconds, and the indoor fan release speed Rfir is, for example, 50 rpm.

[0207] The processing of ST47 to ST49 and ST58 to ST62 described above is related to the operation (hereinafter referred to as the heating operation) for raising the indoor heat exchange temperature Tc to the first indoor heat exchange temperature Tc1 in the indoor unit heat exchange heating operation. By performing the heating operation, the indoor heat exchange temperature Tc can be raised to the first indoor temperature Tc1 (50° C. in this embodiment) as quickly as possible while preventing the protection control during the indoor heat exchange heating operation described later from causing the protection to stop.

[0208] Furthermore, in the process of ST58, when the indoor heat exchange temperature Tc does not reach or exceed the first indoor heat exchange temperature Tc1 even after the first predetermined time tp1 has passed, the indoor heat exchange heating operation is terminated. This is to avoid the following situation: when the indoor heat exchange temperature Tc does not reach or exceed the first indoor heat exchange temperature Tc1 even after the above-mentioned temperature increase operation is performed for the first predetermined time tp1, the indoor heat exchange temperature Tc becomes difficult to rise for some reason, and the result of continuing the indoor heat exchange heating operation in this state is a wasteful operation.

[0209] In ST49 , if the taken-in indoor heat exchange temperature Tc is not lower than the first indoor heat exchange temperature Tc1 ( ST49 -No), the control unit starts the measurement of the timer 2 ( ST50 ). Specifically, the CPU 310 starts the measurement of the timer 2 .

[0210] Next, the control unit executes the temperature maintenance indoor fan control (ST51) as a subroutine of the indoor heat exchange heating operation control, and at the same time executes the temperature maintenance outdoor fan control (ST52) as a subroutine of the indoor heat exchange heating operation control. The temperature maintenance indoor fan control and the temperature maintenance outdoor fan control will be described later.

[0211] Next, the control unit determines whether the flag is 1 (ST53). This flag is, for example, a flag of the CPU 310, and when the indoor heat exchange temperature Tc rises during the indoor heat exchange heating operation and first reaches the third indoor heat exchange temperature Tc3 (55° C. in this embodiment) or above, it is changed from 0 to 1. In addition, the flag is set to 0 by default (at the time of shipment from the factory).

[0212] If the flag is 1 (ST53-Yes), that is, if the indoor heat exchange temperature Tc has reached the third indoor heat exchange temperature Tc3, the control unit resets the timer 1 (ST63) and advances the process to ST56. Specifically, if the CPU 310 confirms that the flag is 1, the timer 1 is reset.

[0213] If the flag is not 1 (ST53-No), that is, if the indoor heat exchange temperature Tc has not reached the third indoor heat exchange temperature Tc3, the control unit determines whether the indoor heat exchange temperature Tc input in ST48 is higher than the third indoor heat exchange temperature Tc3 (ST54). Specifically, the CPU 310 reads the third indoor heat exchange temperature Tc3 from the storage unit 320 and compares it with the input indoor heat exchange temperature Tc.

[0214] If the input indoor heat exchange temperature Tc reaches or exceeds the third indoor heat exchange temperature Tc3 (ST54-Yes), the control unit sets the flag to 1 and resets the timer 1 (ST55), and proceeds to ST56. Specifically, the CPU 310 sets the flag to 1 and resets the timer 1.

[0215] If the input indoor heat exchange temperature Tc is not higher than the third indoor heat exchange temperature Tc3 (ST54-No), the control unit determines whether the first predetermined time tp1 has passed since the timer 1 started measuring in ST47 (ST64). The processing in ST63 is the same as the processing in ST58 and is performed by the CPU 310.

[0216] If the first predetermined time tp1 has passed (ST64-Yes), the control unit resets the timer 1 (ST65) and ends the indoor unit heat exchange heating operation control. The processing of ST65 is the same as the processing of ST61 and is performed by the CPU 310. If the first predetermined time tp1 has not passed (ST64-No), the control unit returns the processing to ST53.

[0217] Furthermore, in the process of ST64, when the indoor heat exchange temperature Tc is not higher than the third indoor heat exchange temperature Tc3 even after the first predetermined time tp1 has passed, the indoor heat exchange heating operation is terminated. This is to avoid the following situation: when the indoor heat exchange temperature Tc does not reach the third indoor heat exchange temperature Tc3 or higher even after the above-mentioned temperature increase operation and the temperature maintenance operation described later are performed for the first predetermined time tp1, the indoor heat exchange temperature Tc becomes difficult to rise for some reason, and the result of continuing the indoor heat exchange heating operation in this state is a wasteful operation.

[0218] After finishing the processing of ST55, the control unit determines whether a predetermined time (hereinafter referred to as the second predetermined time tp2) has passed since the measurement of the timer 2 was started in ST50 (ST56). Specifically, the CPU 310 determines whether the second predetermined time tp2 has passed since the measurement of the timer 2 was started in ST50. Here, the second predetermined time tp2 is predetermined and stored in the storage unit 320, and is the time for maintaining the indoor heat exchange temperature Tc above 55°C in order to significantly reduce the number of molds and bacteria present in the indoor heat exchanger 31, for example, 10 minutes.

[0219] If the second prescribed time tp2 has not passed (ST56-No), the control unit returns the process to ST51. If the second prescribed time tp2 has passed (ST56-Yes), the control unit resets the timer 2 and resets the flag (ST57) to end the indoor unit heat exchange heating operation control. Specifically, the CPU 310 resets the timer 2 and resets the flag. In addition, while stopping the indoor fan 32, the CPU 310 sends a signal including a message for ending the indoor unit heat exchange heating operation control to the outdoor unit 2 via the communication unit 330. The CPU 210 that receives the signal via the communication unit 230 stops the compressor 21 and the outdoor fan 27.

[0220] The processing of ST50 to ST56 and ST63 to ST65 described above is a processing related to the operation (hereinafter referred to as temperature maintenance operation) of maintaining the indoor heat exchange temperature Tc at or above the third indoor heat exchange temperature Tc3 (55°C in this embodiment) during the second predetermined time tp2. By continuing the temperature maintenance operation during the second predetermined time tp2, the number of molds and bacteria present in the indoor heat exchanger 31 can be greatly reduced compared to the case of performing the conventional drying operation in which the indoor heat exchange temperature Tc is about 40°C.

[0221] <Subroutine: Operation control before heating>

[0222] Next, use Figure 8The pre-heating operation control which is a subroutine of the indoor heat exchange heating operation control will be described. In the pre-heating operation control, the compressor 21 is stopped and the refrigerant does not circulate in the refrigerant circuit 10.

[0223] First, the control unit determines whether cooling operation is performed before indoor heat exchange heating operation (ST71). If cooling operation is not performed (ST71-No), the control unit ends the pre-heating operation control. If cooling operation is performed (ST71-Yes), the control unit starts the measurement of timer 3 (ST72). Specifically, CPU 310 starts the measurement of timer 3.

[0224] Next, the control unit sets the indoor fan speed Rfi to a predetermined speed (hereinafter referred to as the indoor fan speed Rfia before heating) and drives the indoor fan 32 (ST73). Specifically, the CPU 310 sets the indoor fan speed Rfi to the indoor fan speed Rfia before heating and drives the indoor fan 32. Here, the indoor fan speed Rfia before heating is obtained in advance by experiments, etc., and is a speed at which the indoor air passes through the interior of the indoor unit 3 during the third predetermined time tp3 described later, and the indoor unit 3 cooled in the cooling operation is heated, thereby suppressing the generation of condensation water caused by the temperature difference between the temperature of the indoor unit 3 and the indoor heat exchange temperature Tc during the heating operation. The indoor fan speed Rfia before heating is, for example, 900 rpm.

[0225] Next, the control unit sets the outdoor fan speed Rfo to a predetermined speed (hereinafter referred to as the outdoor fan speed Rfoa before heating) and drives the outdoor fan 27 (ST74). Specifically, the CPU 210 sets the outdoor fan speed Rfo to the outdoor fan speed Rfoa before heating and drives the outdoor fan 27. Here, the outdoor fan speed Rfoa before heating is obtained by performing a test in advance, etc., and is a speed that suppresses the excessive temperature rise of the outdoor unit control unit 200 during the indoor heat exchange heating operation by cooling the outdoor unit control unit 200 (particularly the inverter not shown that drives the compressor 21) that generates heat during the cooling operation during the third predetermined time tp3 described later. The outdoor fan speed Rfoa before heating is, for example, 650 rpm.

[0226] Next, the control unit determines whether a predetermined time (hereinafter referred to as the third predetermined time tp3) has passed after the measurement of the timer 3 is started in ST72 (ST75). Specifically, the CPU 310 determines whether the third predetermined time tp3 has passed after the measurement of the timer 3 is started in ST75. Here, the third predetermined time tp3 is predetermined and stored in the storage unit 320, and is the following time: if the indoor fan speed Rfi is set to the indoor fan speed Rfia before heating and the outdoor fan speed Rfo is set to the outdoor fan speed Rfoa before heating and is driven during the third predetermined time tp3, the indoor unit 3 cooled in the cooling operation can be heated to a degree that no condensation water is generated during the warming operation, and the outdoor unit control unit 200 generating heat in the cooling operation can be cooled. The third predetermined time tp3 is, for example, 15 minutes.

[0227] If the third predetermined time tp3 has not elapsed (ST75-No), the control unit returns the process to ST75. If the third predetermined time tp3 has elapsed (ST75-Yes), the control unit resets the timer 3 (ST76), ends the pre-heating operation control, and returns to the main routine.

[0228] As described above, when the cooling operation is performed before the indoor heat exchange heating operation, the housing 30 of the indoor unit 3 that is cooled during the cooling operation can be heated by controlling the pre-heating operation before the heating operation. As a result, during the heating operation, the occurrence of condensation water in the housing 30 caused by the temperature difference between the temperature of the indoor unit 3 and the indoor heat exchange temperature Tc can be suppressed, so that the condensation water can be prevented from scattering from the blow-out port 30g of the indoor unit 3 to the room during the indoor heat exchange heating operation. In addition, by driving the outdoor fan 27 by the pre-heating operation control, the outdoor unit control unit 200 that reaches a high temperature during the cooling operation when the outside air temperature is high can be cooled.

[0229] <Subroutine: Indoor fan control when temperature is maintained>

[0230] Next, use Fig. 9 The temperature maintenance indoor fan control as a subroutine of the indoor heat exchange heating operation control is described. In addition, the drive control of the indoor fan 32 is performed only by the indoor unit control unit 300, so in the following description, the control subject is set to the CPU 310 of the indoor unit control unit 300 for description.

[0231] First, the CPU 310 takes in the indoor heat exchange temperature Tc (ST80). Figure 4Next, the CPU 310 calculates the temperature difference (hereinafter referred to as the indoor heat exchange temperature difference ΔTc) obtained by subtracting the indoor heat exchange temperature Tc previously (e.g., 30 seconds ago) from the most recently acquired indoor heat exchange temperature Tc, using the two indoor heat exchange temperatures Tc acquired at intervals (ST81).

[0232] Next, CPU 310 determines whether the indoor heat exchange temperature difference ΔTc calculated in ST81 exceeds 0, that is, whether the indoor heat exchange temperature Tc rises (ST82). If the indoor heat exchange temperature difference ΔTc exceeds 0 (ST82-Yes), CPU 310 refers to the indoor heat exchange temperature difference ΔTc stored in storage unit 320. Figure 6 When "Tc rises" of the indoor fan control table 400, the following processing of ST83 to ST85 is performed.

[0233] First, the CPU 310 determines whether the current indoor heat exchange temperature Tc is lower than the third indoor heat exchange temperature Tc3 (ST83). If the current indoor heat exchange temperature Tc is lower than the third indoor heat exchange temperature Tc3 (ST83-Yes), the CPU 310 sets the indoor fan speed Rfi to the speed obtained by subtracting 10 rpm from the current indoor fan speed Rfi (ST86), ends the indoor fan control during temperature maintenance, and returns to the main program.

[0234] If the current indoor heat exchange temperature Tc is not lower than the third indoor heat exchange temperature Tc3 (ST83-No), the CPU 310 determines whether the current indoor heat exchange temperature Tc is higher than the third indoor heat exchange temperature Tc3 and lower than the fourth indoor heat exchange temperature Tc4 (ST84). If the current indoor heat exchange temperature Tc is higher than the third indoor heat exchange temperature Tc3 and lower than the fourth indoor heat exchange temperature Tc4 (ST84-Yes), the CPU 310 does not change the indoor fan speed Rfi (ST87), ends the indoor fan control during temperature maintenance, and returns to the main program.

[0235] If the current indoor heat exchange temperature Tc is not higher than the third indoor heat exchange temperature Tc3 and lower than the fourth indoor heat exchange temperature Tc4 (ST84-No), that is, if the current indoor heat exchange temperature Tc is higher than the fourth indoor heat exchange temperature Tc4, then CPU310 sets the indoor fan speed Rfi to the speed obtained by adding 70 rpm to the current indoor fan speed Rfi (ST85), ends the indoor fan control during temperature maintenance, and returns to the main program.

[0236] In ST82, if the indoor heat exchange temperature difference ΔTc does not exceed 0 (ST82-No), CPU 310 determines whether the indoor heat exchange temperature difference ΔTc calculated in ST81 is 0, that is, whether the indoor heat exchange temperature Tc has not changed (ST88). If the indoor heat exchange temperature difference ΔTc is 0 (ST88-Yes), CPU 310 refers to the indoor heat exchange temperature difference ΔTc stored in storage unit 320. Figure 6 When "Tc is maintained" of the indoor fan control table 400, the following processing of ST89 to ST95 is performed.

[0237] First, the CPU 310 determines whether the current indoor heat exchange temperature Tc is lower than the second indoor heat exchange temperature Tc2 (ST89). If the current indoor heat exchange temperature Tc is lower than the second indoor heat exchange temperature Tc2 (ST89-Yes), the CPU 310 sets the indoor fan speed Rfi to the speed obtained by subtracting 40 rpm from the current indoor fan speed Rfi (ST93), ends the indoor fan control during temperature maintenance, and returns to the main program.

[0238] If the current indoor heat exchange temperature Tc is not lower than the second indoor heat exchange temperature Tc2 (ST89-No), the CPU 310 determines whether the current indoor heat exchange temperature Tc is higher than the second indoor heat exchange temperature Tc2 and lower than the third indoor heat exchange temperature Tc3 (ST90). If the current indoor heat exchange temperature Tc is higher than the second indoor heat exchange temperature Tc2 and lower than the third indoor heat exchange temperature Tc3 (ST90-Yes), the CPU 310 sets the indoor fan speed Rfi to the speed obtained by subtracting 30 rpm from the current indoor fan speed Rfi (ST94), ends the indoor fan control during temperature maintenance, and returns to the main program.

[0239] If the current indoor heat exchange temperature Tc is not higher than the second indoor heat exchange temperature Tc2 and lower than the third indoor heat exchange temperature Tc3 (ST90-No), the CPU 310 determines whether the current indoor heat exchange temperature Tc is higher than the third indoor heat exchange temperature Tc3 and lower than the fourth indoor heat exchange temperature Tc4 (ST91). If the current indoor heat exchange temperature Tc is higher than the third indoor heat exchange temperature Tc3 and lower than the fourth indoor heat exchange temperature Tc4 (ST91-Yes), the CPU 310 does not change the indoor fan speed Rfi (ST95), but ends the indoor fan control during temperature maintenance and returns to the main program.

[0240] If the current indoor heat exchange temperature Tc is not higher than the third indoor heat exchange temperature Tc3 and lower than the fourth indoor heat exchange temperature Tc4 (ST93-No), that is, if the current indoor heat exchange temperature Tc is higher than the fourth indoor heat exchange temperature Tc4, then CPU310 sets the indoor fan speed Rfi to the speed obtained by adding 50 rpm to the current indoor fan speed Rfi (ST98), ends the indoor fan control during temperature maintenance, and returns to the main program.

[0241] In ST88, if the indoor heat exchange temperature difference ΔTc is not zero (ST88-No), that is, the indoor heat exchange temperature Tc decreases, the CPU 310 refers to the indoor heat exchange temperature difference ΔTc stored in the storage unit 320. Figure 6 When "Tc decreases" of the indoor fan control table 400, the following processing of ST96 to ST98 is performed.

[0242] First, the CPU 310 determines whether the current indoor heat exchange temperature Tc is lower than the third indoor heat exchange temperature Tc3 (ST96). If the current indoor heat exchange temperature Tc is lower than the third indoor heat exchange temperature Tc3 (ST96-Yes), the CPU 310 sets the indoor fan speed Rfi to the speed obtained by subtracting 40 rpm from the current indoor fan speed Rfi (ST98), ends the indoor fan control during temperature maintenance, and returns to the main program.

[0243] If the current indoor heat exchange temperature Tc is not lower than the third indoor heat exchange temperature Tc3 (ST96-No), that is, the current indoor heat exchange temperature Tc is above the third indoor heat exchange temperature Tc3, CPU310 does not change the indoor fan speed Rfi (ST97), ends the indoor fan speed control when maintaining the temperature, and returns to the main program.

[0244] Furthermore, as described above, when the indoor fan control is performed when the temperature is maintained using the indoor fan control table 400, the indoor fan speed Rfi is set between the upper limit speed and the lower limit speed (900 rpm and 300 rpm) of the indoor fan speed Rfi. If the indoor fan speed Rfi is increased by the speed determined in the indoor fan control table 400 and reaches 900 rpm, the indoor fan speed Rfi is maintained at 900 rpm even if the indoor fan speed Rfi is increased thereafter. In addition, if the indoor fan speed Rfi is reduced by the speed determined in the indoor fan control table 400 and reaches 300 rpm, the indoor fan speed Rfi is maintained at 300 rpm even if the indoor fan speed Rfi is reduced thereafter.

[0245] As described above, during the temperature maintenance operation performed during the indoor heat exchange heating operation, by using the indoor fan control table 400 to control the indoor fan during temperature maintenance, the indoor heat exchange temperature Tc can be maintained between the third indoor heat exchange temperature Tc3 (=55°C) and the fourth indoor heat exchange temperature Tc4 (=57°C) for 10 minutes.

[0246] <Subroutine: Outdoor fan control when temperature is maintained>

[0247] Next, the outdoor fan control during temperature maintenance as a subroutine of the indoor heat exchange heating operation control is described. In addition, the drive control of the outdoor fan 27 is only performed by the outdoor unit control unit 200, so in the following description, the control subject is set to the CPU 210 of the outdoor unit control unit 200 for description.

[0248] First, CPU 210 acquires indoor temperature Ti from indoor unit 3 via communication unit 230 and acquires outside air temperature To detected by outside air temperature sensor 73 via sensor input unit 240 (ST111). CPU 210 acquires indoor temperature Ti and outside air temperature To regularly (for example, every 30 seconds).

[0249] Next, CPU 210 determines whether the outside air temperature To input in ST111 is lower than a predetermined first outside air temperature (hereinafter referred to as a first threshold outside air temperature Top1) (ST112). For example, the first threshold outside air temperature Top1 is Figure 6 The outside air temperature determined in the outdoor fan control table 500 of (B) is: 16°C.

[0250] If the input external air temperature To is lower than the first threshold external air temperature Top1 (ST112-Yes), CPU210 refers to the outdoor fan control table 500 stored in the storage unit 220, drives the outdoor fan 27 (ST117) at the outdoor fan speed Rfo corresponding to the compressor speed Rc, ends the outdoor fan control when the temperature is maintained, and returns to the main program.

[0251] If the input external air temperature To is not lower than the first threshold external air temperature Top1 (ST112-No), CPU 210 determines whether the input external air temperature To is higher than the first threshold external air temperature Top1 and lower than a predetermined second external air temperature (hereinafter referred to as the second threshold external air temperature Top2) (ST113). The second threshold external air temperature Top2 is a temperature higher than the first threshold external air temperature Top1, for example, Figure 6 The outdoor fan control table 500 of (B) determines the outside air temperature: 24°C.

[0252] If the input external air temperature To is not above the first threshold external air temperature Top1 and below the second threshold external air temperature Top2 (ST113-No), that is, if the input external air temperature To is above the second threshold external air temperature Top2, the CPU 210 refers to the outdoor fan control table 500 stored in the storage unit 220, sets the outdoor fan speed Rfo to 0 rpm (ST118), that is, stops the outdoor fan 27, ends the outdoor fan control during temperature maintenance, and returns to the main program.

[0253] If the input outside air temperature To is above the first threshold outside air temperature Top1 and below the second threshold outside air temperature Top2 (ST113-Yes), CPU 210 determines whether the indoor temperature Ti input in ST111 is below a predetermined indoor temperature (hereinafter referred to as threshold indoor temperature Tip) (ST114). Figure 6 The indoor temperature determined in the outdoor fan control table 500 of (B) is: 27°C.

[0254] If the input indoor temperature Ti is not lower than the threshold indoor temperature Tip (ST114-No), that is, if the input indoor temperature Ti is higher than the threshold indoor temperature Tip, the CPU 210 causes the process to proceed to ST118. If the input indoor temperature Ti is lower than the threshold indoor temperature Tip (ST114-Yes), the CPU 210 determines whether the current outdoor fan speed Rfo is 0 rpm (ST115).

[0255] If the current outdoor fan speed Rfo is 0 rpm (ST115-Yes), the CPU 210 causes the process to enter ST118, that is, the outdoor fan 27 is kept stopped. If the current outdoor fan speed Rfo does not reach 0 rpm (ST115-No), the CPU 210 sets the outdoor fan speed Rfo to a predetermined speed (hereinafter referred to as the outdoor fan speed Rfob during maintenance) (ST116), ends the outdoor fan control during temperature maintenance, and returns to the main program. For example, the outdoor fan speed Rfob during maintenance is Figure 6 The outdoor fan speed Rfo determined in the outdoor fan control table 500 of (B) is: 190 rpm.

[0256] As described above, in the temperature maintenance operation performed during the indoor heat exchange heating operation, the outdoor fan control during temperature maintenance is performed using the outdoor fan control table 500. Thus, by controlling the outdoor fan 27 based on the outdoor fan control table 500, when the indoor heat exchange temperature Tc is maintained in the range of 55°C to 57°C, the discharge pressure of the compressor 21 can be kept within the upper limit of the use range.

[0257] In addition, as described in the process of ST115, when the outdoor fan 27 is stopped in the temperature maintenance outdoor fan control, the outdoor fan 27 is not driven until the indoor heat exchange heating operation is completed. This is to prevent the evaporation capacity of the outdoor heat exchanger 23 from increasing and the evaporation pressure from increasing by restarting the outdoor fan 27 when the indoor heat exchange temperature Tc is maintained at 55°C or above, and at the same time, the discharge pressure of the compressor 21 also increases and exceeds the upper limit of the use range.

[0258] <Protection control during indoor heat exchange heating operation>

[0259] Next, use Fig.11 The protection control during the indoor heat exchange heating operation is described below, in which the discharge pressure of the compressor 21 does not exceed the upper limit of the operating range during the indoor heat exchange heating operation. Fig.11 In , ST indicates a processing step, and the number after it indicates the step number. In addition, the indoor heat exchange heating operation protection control is executed when the indoor heat exchange heating is performed, and is different from the heating operation protection control executed when the heating operation is performed.

[0260] First, the control unit takes in the indoor heat exchange temperature Tc, the discharge temperature Td, the temperature of the outdoor heat exchanger 23 (hereinafter referred to as the outdoor heat exchange temperature Te), and the outside air temperature To (ST131). Figure 4 The outside air temperature To is obtained by the same method as ST11 in the heating operation protection control described above, so the description is omitted. Fig.10 The outdoor heat exchange temperature Te is inputted by the CPU 210 via the sensor input unit 240 periodically (for example, every 30 seconds) detected by the outdoor heat exchange sensor 72.

[0261] Next, the control unit determines whether the indoor heat exchange temperature Tc taken in in ST131 is a temperature higher than the first threshold indoor heat exchange temperature Tch1, that is, a predetermined temperature (hereinafter referred to as the second threshold indoor heat exchange temperature Tch2) or above (ST132). Specifically, the CPU 310 reads the second threshold indoor heat exchange temperature Tch2 pre-stored in the storage unit 320, and compares it with the indoor heat exchange temperature Tc. In addition, the second threshold indoor heat exchange temperature Tch2 is obtained in advance by conducting experiments, etc., and is a temperature that is higher than the first threshold indoor heat exchange temperature Tch1 and is a predetermined temperature lower than the indoor heat exchange temperature Tc corresponding to the upper limit value of the use range of the discharge pressure of the compressor 21 mentioned above. The second threshold indoor heat exchange temperature Tch2 is, for example, 59°C.

[0262] If the indoor heat exchange temperature Tc is above the second threshold indoor heat exchange temperature Tch2 (ST132-Yes), the control unit stops the indoor heat exchange heating operation (ST136), and ends the processing related to the protection control during the indoor heat exchange heating operation. In addition, the operation of the air conditioner 1 can also be stopped after the processing of ST136 is performed. In addition, it can also be set to stop the compressor 21 and only continue to drive the air supply operation of the indoor fan 32. Alternatively, the compressor 21 can be driven at a specified speed, and the opening D of the expansion valve 24 is opened at an opening larger than the specified expansion valve opening Dp during the indoor heat exchange heating operation, and the indoor fan 32 is driven at a higher indoor fan speed Rfi than during the indoor heat exchange heating operation, and the drying operation of the indoor heat exchanger 31 is continued for a certain period of time. In this drying operation, since the opening D of the expansion valve 24 is increased compared with the indoor heat exchange heating operation, and the indoor fan speed Rfi is also increased, the discharge pressure of the compressor 21 is lower than that during the indoor heat exchange heating operation.

[0263] If the indoor heat exchange temperature Tc is not equal to or higher than the second threshold indoor heat exchange temperature Tch2 (ST132-No), the control unit determines whether the discharge temperature Td input in ST131 is equal to or higher than the first threshold discharge temperature Tdh1 (ST133). Specifically, the CPU 210 determines whether the discharge temperature Td is equal to or higher than the first threshold discharge temperature Tdh1.

[0264] If the input discharge temperature Td is equal to or higher than the first threshold discharge temperature Tdh1 (ST133-Yes), the control unit advances the process to ST136.

[0265] If the input discharge temperature Td is not above the first threshold discharge temperature Tdh1 (ST133-No), the control unit determines whether the outdoor heat exchange temperature Te input in ST131 is above the specified outdoor heat exchange temperature (hereinafter referred to as the threshold outdoor heat exchange temperature Teh) (ST134). Specifically, the CPU 210 determines whether the input outdoor heat exchange temperature Te is above the threshold outdoor heat exchange temperature Teh. Here, the threshold outdoor heat exchange temperature Teh is obtained in advance by experiments and stored in the storage unit 220. If the outdoor heat exchange temperature Te is above the threshold outdoor heat exchange temperature Teh, the suction pressure of the compressor 21 rises, and the compression ratio (ratio of discharge pressure to suction pressure) of the compressor 21 may be lower than the lower limit value of the use range.

[0266] If the acquired outdoor heat exchange temperature Te is equal to or higher than the threshold outdoor heat exchange temperature Teh (ST134-Yes), the control unit advances the process to ST136.

[0267] If the input outdoor heat exchange temperature Te is not above the threshold outdoor heat exchange temperature Teh (ST134-No), the control unit determines whether the external air temperature To input in ST131 is above the specified external air temperature (hereinafter referred to as the third threshold external air temperature Top3) (ST135). Specifically, the CPU 310 determines whether the input external air temperature To is above the third threshold external air temperature Top3. Here, the third threshold external air temperature Top3 is obtained in advance through experiments and stored in the storage unit 220. If the indoor heat exchange heating operation is performed when the external air temperature To is above the third threshold external air temperature Top3, the discharge pressure of the compressor 21 will excessively increase, and the discharge pressure of the compressor 21 may exceed the lower limit of the operating range. The third threshold external air temperature Top3 is a temperature higher than the first threshold external air temperature Top1 or the second threshold external air temperature Top2, for example, 43°C.

[0268] If the input outside air temperature To is not higher than the third threshold outside air temperature Top3 (ST134-No), the control unit returns the process to ST131. If the input outside air temperature To is higher than the third threshold outside air temperature Top3 (ST134-Yes), the control unit returns the process to ST136.

[0269] As described above, in the protection control during the indoor heat exchange heating operation, the compressor 21 is not stopped until the indoor heat exchange temperature Tc is higher than the second threshold indoor heat exchange temperature Tch2 (=59°C) which is higher than the first threshold indoor heat exchange temperature Tch1 (=55°C) in the protection control during the heating operation. Thus, in the outdoor heat exchange heating operation, the indoor heat exchange temperature Tc can be maintained at 55°C to 57°C, and the compressor 21 is stopped if the indoor heat exchange temperature Tc is higher than the second threshold indoor heat exchange temperature Tch2, so that the discharge pressure of the compressor 21 can be suppressed from exceeding the upper limit of the use range.

[0270] In addition, in the protection control during the indoor heat exchange heating operation, if the discharge temperature Td of the compressor 21 is a temperature lower than the threshold temperature for stopping the compressor 21 under the protection control during the heating operation, that is, the second threshold discharge temperature Tdh2 (=115°C), that is, the first threshold discharge temperature Tdh1 (=105°C) or more, the compressor 21 is stopped. When the indoor heat exchange temperature Tc is maintained at 55°C to 57°C during the indoor heat exchange heating operation, the discharge temperature Td of the compressor 21 is likely to rise, and the discharge pressure is also likely to rise. Therefore, if the discharge temperature Td is above the first threshold discharge temperature Tdh1 which is lower than the second threshold discharge temperature Tdh2, the compressor 21 is stopped, thereby effectively suppressing the discharge pressure of the compressor 21 from exceeding the upper limit of the use range.

[0271] In addition, the protection control during the indoor heat exchange heating operation also includes stopping the compressor 21 based on the outdoor heat exchange temperature Te that is not included in the protection control during the heating operation. It is believed that the indoor heat exchange heating operation of the present invention is mostly performed in the summer when the possibility of mold and bacteria breeding increases due to the condensation water generated in the indoor heat exchanger 31. The outside air temperature To is high in summer. Since the outside air temperature To is high, the outdoor heat exchange temperature Te of the outdoor heat exchanger 23 that functions as an evaporator becomes high during the indoor heat exchange heating operation. In this case, since the outdoor heat exchange temperature Te becomes high, the suction pressure of the compressor 21 may increase. Therefore, in the protection control during the indoor heat exchange heating operation, if the outdoor heat exchange temperature Te is above the threshold outdoor heat exchange temperature Teh, the compressor 21 is stopped to suppress the increase in the suction pressure of the compressor 21, thereby suppressing the compression ratio of the compressor 21 from being lower than the lower limit of the use range.

[0272] <About Wetting Control Operation>

[0273] In the present invention, before the above-mentioned indoor heat exchange heating operation, a humidification control operation may be performed as follows. The humidification control operation is to control the indoor heat exchange temperature based on the temperature and humidity of the indoor heat exchanger 31 after the cooling operation so as to wet the surface of the indoor heat exchanger 31 with a specific amount of condensed water. As described above, when the indoor heat exchange temperature is maintained at a high temperature in a state where condensed water exists on the surface of the indoor heat exchanger 31, the residual rate of mold and bacteria existing on the surface of the indoor heat exchanger 31 can be greatly reduced. Here, a humidity signal including humidity information of the measured humidity is supplied from an indoor humidity sensor (not shown) that measures the relative humidity in the indoor unit 3 to the sensor input unit 340 of the indoor unit control unit 300 in the indoor unit 3.

[0274] like Fig.12 As shown, when the control unit recognizes that the cooling operation is finished, it stops the rotation of the indoor fan 32 in ST137. The stillness of the indoor fan 32 suppresses the evaporation of condensed water from the surface of the indoor heat exchanger 31. At this time, the four-way valve 22 maintains the position during the cooling operation. In addition, in ST137, in addition to stopping the rotation of the indoor fan 32, the control unit can also reduce the rotation speed of the indoor fan 32 or implement intermittent rotation. The rotation of the indoor fan 32 can be appropriately adjusted according to the amount of condensed water.

[0275] In ST138, the control unit determines the amount of moisture of the indoor heat exchanger 31 based on the amount of condensed water generated on the surface of the indoor heat exchanger 31. When determining the amount of moisture, the control unit estimates the amount of saturated water vapor based on the output signals of the indoor temperature sensor 75 and the indoor humidity sensor. The control unit determines the amount of condensed water based on the estimated amount of saturated water vapor and the duration and elapsed time counted by a timer (not shown) installed in the indoor unit 3. Usually, the temperature of the indoor heat exchanger 31 is low after the cooling operation, and condensed water is generated on the surface of the indoor heat exchanger 31.

[0276] When the estimated amount of wetting is less than the predetermined amount, the control unit cools the indoor heat exchanger 31 in ST139. When cooling the indoor heat exchanger 31, the control unit instructs the operation of the expansion valve 24 and the compressor 21 to lower the evaporation temperature of the refrigerant in the indoor heat exchanger 31. As a result, the temperature of the indoor heat exchanger 31 is reduced, promoting the generation of condensation water. Sufficient wetting is ensured on the surface of the indoor heat exchanger 31. Regarding the predetermined amount of wetting, in order to perform wet heat sterilization that can kill bacteria and molds by applying heat under high humidity and reduce their number at a temperature lower than that in a dry state, the predetermined amount of wetting can be set to a water amount that does not lose the effectiveness of wet heat sterilization due to evaporation during the heating of the indoor heat exchanger 31.

[0277] If the estimated amount of wetting reaches a predetermined amount, the control unit heats the indoor heat exchanger 31 in ST140. The condensation of the refrigerant is used when heating the indoor heat exchanger 31. At this time, the control unit performs switching of the four-way valve 22. The four-way valve 22 is switched to the position during heating operation. Here, the temperature of the indoor heat exchanger 31 during heating is set to above 45 degrees Celsius. Preferably, the temperature of the indoor heat exchanger 31 is set to above 60 degrees Celsius. In this way, the indoor heat exchanger 31 is heated without having to go through the drying action performed in the past, and the condensation water will not evaporate on the surface of the indoor heat exchanger 31. The condensation water is heated by the indoor heat exchanger 31. Bacteria and mold are heated in the heated condensation water. Therefore, bacteria and mold are sterilized by wet heat. Bacteria and mold can be killed and their number can be reduced.

[0278] In particular, when the temperature of the indoor heat exchanger 31 is set to be above 45 degrees Celsius, the condensed water is heated to above 45 degrees Celsius, and the wet heat sterilization of bacteria and molds is effectively achieved. Moreover, when the temperature of the indoor heat exchanger 31 is set to be above 60 degrees Celsius, the wet heat sterilization of bacteria and molds can be achieved more effectively. The sterilization time is shortened. However, since it is desirable to suppress the evaporation of the condensed water as much as possible, it is ideal that the temperature of the indoor heat exchanger 31 is set to a temperature as low as possible below 70 degrees Celsius. In the dry state of the above-mentioned heat exchanger, even if the temperature is set to be above 45 degrees Celsius, the sterilization of bacteria and molds cannot be achieved.

[0279] When heating the indoor heat exchanger 31, the opening degree of the expansion valve 24 and the rotation of the fans 27 and 32 may be appropriately adjusted so that the temperature of the indoor heat exchanger 31 does not exceed 60 degrees and become an overload condition.

[0280] In ST141, the control unit determines the completion of moist heat sterilization. When judging, for example, the control unit uses a timer clock. The timer measures the duration of the set temperature. When the duration of the set temperature reaches a specified value, the control unit ends the moist heat sterilization. If the duration of the set temperature is lower than the specified value, the control unit continues the heating action. The specified value of the duration of the set temperature is as long as it is more than the time to obtain the moist heat sterilization effect. According to the applicant's experiment, if it is Escherichia coli, it is set to more than 3 minutes, and if it is black mold, it is set to more than 5 minutes, thereby, the effect of moist heat sterilization can be obtained. In addition, it is known that if it is Legionella, it is ideally more than 10 minutes. At this time, the control unit monitors the action of the compressor 21 through ST142. When an overload of the compressor 21 is detected during heating before the set temperature, in ST7, the control unit reduces the discharge temperature of the compressor 21 and ends the heating action. If no overload is detected, the heating action is continued before it is determined in ST141 that the moist heat sterilization is completed.

[0281] Here, the overload condition of the compressor 21 set during condensation is relaxed compared to the overload condition of the compressor 21 set during heating operation. That is, the discharge temperature that becomes the threshold of the overload condition is set higher, or the time until the overload protection action is set longer when the discharge temperature exceeds the threshold of the overload condition for a predetermined time. Since the overload condition of the compressor 21 is relaxed during the humidification control operation, the indoor heat exchanger 31 can be heated to a higher temperature than during the heating operation. Moisture heat sterilization of bacteria and mold is achieved.

[0282] During the humidification control operation of the air conditioner 1, the drying process in the indoor unit 3 can also be performed following the wet heat sterilization process. In this drying process, the rotation of the indoor fan 32 is started while maintaining the heating state of the indoor heat exchanger 31. When the indoor fan 32 rotates, the control unit determines the rotation speed of the indoor fan 32. The rotation of the indoor fan 32 promotes the evaporation of the heated condensation water. At this time, the blow-out port of the indoor unit 3 can also be closed by the upper and lower wind deflectors 35. When the blow-out port is closed, the control unit determines the minimum angle of the upper and lower wind deflectors 35. In this way, the blowing of warm air after the cooling operation can be avoided. By continuing the dry heating following the wet heat sterilization process, the growth of bacteria and molds remaining in the wet heat sterilization can be suppressed.

Claims

1. An air conditioner, characterized in that: have: Indoor heat exchanger; an indoor fan that generates an airflow toward the indoor heat exchanger; as well as A control unit performs a heating operation and an indoor heat exchange heating operation, wherein in the heating operation, the indoor heat exchanger is made to function as a condenser to supply warm air to the room, and in the indoor heat exchange heating operation, the indoor heat exchanger is made to function as a condenser in a state where condensation water is attached to the indoor heat exchanger, and the temperature of the indoor heat exchanger is maintained at a level of not less than 45 degrees Celsius and not more than 59 degrees Celsius, The control unit maintains the rotation of the indoor fan while setting a lower limit rotation speed lower than a lower limit rotation speed during the heating operation during the indoor heat exchange heating operation.

2. The air conditioner according to claim 1, characterized in that: In the indoor heat exchange heating operation, the operation of the compressor supplying high-pressure refrigerant to the indoor heat exchanger is not changed, and the rotation speed of the indoor fan is controlled to maintain the temperature of the indoor heat exchanger at 45 degrees Celsius or more and less than 59 degrees Celsius.

3. The air conditioner according to claim 2, characterized in that: During the indoor heat exchange heating operation, the control unit increases the rotation speed of the indoor fan at a threshold value lower than 59 degrees Celsius to maintain the temperature of the indoor heat exchanger lower than 59 degrees Celsius.

4. The air conditioner according to claim 1, characterized in that: An outdoor heat exchanger and an outdoor fan for taking in external air into the outdoor heat exchanger are provided. The control unit stops the rotation of the outdoor fan when detecting an outside air temperature that is equal to or higher than a predetermined temperature.

5. The air conditioner according to claim 1, characterized in that: The indoor unit includes an up-and-down wind deflector disposed at the air outlet of the indoor unit and set in a horizontal position during the indoor heat exchange heating operation.

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