JP7255708B2 - Air conditioner outdoor unit, air conditioner, and control method for air conditioner outdoor unit - Google Patents

Description

The present disclosure relates to an outdoor unit of an air conditioner, an air conditioner, and a control method for the outdoor unit of the air conditioner.

In an air conditioner, if the outside air temperature drops below freezing while the operation is stopped, the temperature of the compressor housed in the outdoor unit will also drop, so the refrigerant circuit in the device will It is known that a phenomenon occurs in which the refrigerant condenses and liquefies in the compressor and accumulates in the compressor (hereinafter also referred to as "stagnation phenomenon"). Refrigerant accumulated in the compressor dissolves in lubricating oil in the compressor. This dilutes the lubricating oil and reduces the viscosity of the lubricating oil. If the compressor is started in this state, low-viscosity lubricating oil will be supplied to the drive shaft of the compressor. In addition, when the compressor is started, the pressure drops suddenly, causing oil foaming, in which the liquefied refrigerant rapidly vaporizes and the lubricating oil bubbles. This can cause the compressor to suck up a lot of lubricating oil along with the refrigerant, causing a shortage of lubricating oil in the compressor.

In order to prevent this refrigerant stagnation phenomenon, a method is known in which the compressor is heated by a heating means such as a heater before the compressor is started when the outside air temperature is low, and the liquefied refrigerant is pre-vaporized.

As a device having such a heating means, Patent Document 1 describes a heat pump configured by sequentially connecting a compressor, a condenser, an expansion valve, and an evaporator in a ring. This heat pump has an accumulator between the evaporator and the compressor. A compressor heating section for heating the inside of the compressor is provided outside the shell of the compressor, and an accumulator heating section for heating the inside of the accumulator is provided outside the shell of the accumulator. In addition, this heat pump includes a pressure sensor that detects the pressure on the suction side of the compressor, a first temperature sensor that detects the temperature of an oil reservoir that stores lubricating oil provided at the bottom of the compressor, and a bottom of the accumulator ( and a second temperature sensor that detects the temperature of the liquid refrigerant reservoir.

When the start of operation of the heat pump is instructed while the compressor is stopped, the detected temperature of the first temperature sensor becomes higher than the saturation temperature corresponding to the detected pressure of the pressure sensor before starting the compressor. As such, the compressor is heated. As a result, the liquid refrigerant dissolved in the lubricating oil in the oil pool can be vaporized. Also, the accumulator is heated within a range in which the temperature detected by the second temperature sensor does not exceed the temperature detected by the first temperature sensor. This prevents the refrigerant vaporized in the accumulator from recondensing in the compressor.

JP 2015-25578 A (paragraphs 0030, 0035, 0038, 0041, 0042, 0049-0056, FIGS. 1 and 2)

In the conventional apparatus described above, three sensors are used to control the heating of the compressor and the accumulator to prevent the stagnation phenomenon of the refrigerant. In order to perform control by comparing the temperature detected by the first temperature sensor and the saturation temperature corresponding to the pressure detected by the pressure sensor, a pressure sensor is required in addition to the temperature sensor. For this reason, since the cost of the sensor increases, there has been a demand for cost reduction.

DISCLOSURE OF THE INVENTION The present disclosure has been made to solve the above-described problems, and is an outdoor unit of an air conditioner that can perform heating control of a compressor and an accumulator to prevent refrigerant stagnation at low cost. A control method for an outdoor unit of a conditioner and an air conditioner is obtained.

The outdoor unit of the air conditioner according to the present disclosure includes an outdoor heat exchanger that exchanges heat between the outside air and the refrigerant, a compressor that sucks, compresses, and discharges the refrigerant, and is provided on the suction side of the compressor, An accumulator that stores liquid refrigerant, a compressor heating unit that is provided in the compressor and heats the compressor, an accumulator heating unit that is provided in the accumulator and heats the accumulator, and an outside air temperature sensor that detects the outside air temperature. A heating control unit that acquires the detected temperature and performs control for causing the compressor heating unit to heat the compressor and control for causing the accumulator heating unit to heat the accumulator based on the detected temperature, and heating control When the detected temperature becomes equal to or lower than the first reference value, the compressor heating section starts heating the compressor, and when the detected temperature becomes equal to or lower than the second reference value which is smaller than the first reference value, the accumulator is heated. It initiates the heating of the accumulator by the unit .

Further, a method for controlling an outdoor unit of an air conditioner according to the present disclosure includes an outdoor heat exchanger that performs heat exchange between outside air and refrigerant, a compressor that sucks in, compresses, and discharges refrigerant, and suction of the compressor. an accumulator that is provided on the side and stores liquid refrigerant; a compressor heating unit that is provided in the compressor and heats the compressor; an accumulator heating unit that is provided in the accumulator and heats the accumulator; A method for controlling an outdoor unit of an air conditioner, comprising: a heating control unit that controls an accumulator heating unit, the heating control unit obtaining a detected temperature detected by an outside air temperature sensor that detects the outside air temperature; a step in which the heating control unit causes the compressor heating unit to heat the compressor when the detected temperature becomes equal to or less than a first reference value; if the heating control unit causes the accumulator heating unit to heat the accumulator.

According to the present disclosure, the heating control unit causes the compressor heating unit to heat the compressor and the accumulator heating unit to heat the accumulator based on the temperature detected by the outside air temperature sensor. It can be implemented at a cost.

1 is a schematic diagram showing the configuration of an air conditioner showing Embodiment 1. FIG. 2 is a schematic diagram showing the main internal configuration of the outdoor unit of the air conditioner showing Embodiment 1. FIG. 4 is a block diagram showing functions of a heating control section of the outdoor unit of the air conditioner showing Embodiment 1. FIG. 3 is a diagram showing an example of a hardware configuration of a processing circuit of a heating control unit of the outdoor unit of the air conditioner showing Embodiment 1. FIG. 4 is a flow chart of heating control of the compressor and the accumulator in the outdoor unit of the air conditioner showing Embodiment 1. FIG. 4 is a flow chart of heating control of the compressor and the accumulator in the outdoor unit of the air conditioner showing Embodiment 1. FIG. 4 is an example of a timing chart of heating control of the compressor and the accumulator in the outdoor unit of the air conditioner showing Embodiment 1. FIG. 9 is an example of a timing chart of heating control of the compressor and the accumulator in the outdoor unit of the air conditioner showing Embodiment 2. FIG. 10 is an example of a timing chart of heating control of a compressor and an accumulator in an outdoor unit of an air conditioner showing Embodiment 3. FIG.

Embodiments will be described below with reference to the accompanying drawings. The same reference numerals are given to the same or corresponding parts in each figure.

Embodiment 1.
FIG. 1 is a schematic diagram showing the configuration of an air conditioner 1 according to Embodiment 1. As shown in FIG. In FIG. 1 , solid-line arrows indicate the flow of refrigerant during cooling operation of the air conditioner 1 , and dashed-line arrows indicate the flow of refrigerant during heating operation of the air conditioner 1 . The cooling operation is an operation in which cold air is blown from the indoor unit 10, and the heating operation is an operation in which warm air is blown from the indoor unit 10. As shown in FIG. 1 , the air conditioner 1 includes an indoor unit 10 and an outdoor unit 20 . In the air conditioner 1, the refrigerant circuit 30 is configured by connecting the accumulator 44, the compressor 42, the outdoor heat exchanger 40, the expansion valve 46, and the indoor heat exchanger 50 via refrigerant pipes 31. there is A refrigerant circulates in the refrigerant circuit 30 .

The indoor unit 10 performs cooling, heating, and the like of a space to be air-conditioned. The air-conditioned space is, for example, a space inside a building in which the indoor unit 10 is installed. The indoor unit 10 has an indoor heat exchanger 50 .

The indoor heat exchanger 50 exchanges heat between the refrigerant and the air in the space to be air-conditioned. Air in the air-conditioned space is supplied to the indoor heat exchanger 50 by the blower 51 provided in the indoor unit 10 . The indoor heat exchanger 50 functions as an evaporator during cooling operation, and evaporates and vaporizes the refrigerant. The indoor heat exchanger 50 functions as a condenser during heating operation, and condenses and liquefies the refrigerant. The indoor heat exchanger 50 is, for example, a fin-and-tube heat exchanger made of copper, aluminum, or the like.

The outdoor unit 20 is usually installed in a space outside the building. The outdoor unit 20 includes an outdoor heat exchanger 40 , a compressor 42 and an accumulator 44 .

The outdoor heat exchanger 40 exchanges heat between the outside air and the refrigerant. The outdoor air is, for example, the air outside the building, and is supplied to the outdoor heat exchanger 40 by the blower 41 provided in the outdoor unit 20 . The outdoor heat exchanger 40 functions as a condenser during cooling operation, and condenses and liquefies the refrigerant. The outdoor heat exchanger 40 functions as an evaporator during heating operation, and evaporates and vaporizes the refrigerant. The outdoor heat exchanger 40 is a fin-and-tube heat exchanger made of copper, aluminum, or the like, for example.

The compressor 42 sucks in a low-temperature, low-pressure refrigerant, compresses the refrigerant into a high-temperature, high-pressure state, and discharges it. The compressor 42 has a function of circulating the refrigerant in the refrigerant circuit 30 . Compressor 42 is constituted by compressors, such as a rotary type and a scroll type, for example.

The accumulator 44 is provided on the suction side of the compressor 42 and stores liquid refrigerant. The accumulator 44 stores surplus refrigerant caused by the difference in operating conditions between the cooling operation and the heating operation, surplus refrigerant due to transient changes in operation, and the like. Also, the accumulator 44 separates and stores liquid refrigerant that has not been completely evaporated in the outdoor heat exchanger 40 that functions as an evaporator during heating operation, for example. This prevents liquid refrigerant from being sucked into the compressor and causing damage to valves and the like of the compressor due to liquid compression.

In a general air conditioner, the heat capacity of the compressor is larger than that of the accumulator. Also in this embodiment, the heat capacity of the compressor 42 is larger than the heat capacity of the accumulator 44 . This is mainly because the compressor 42 and the accumulator 44 are made of the same material for the container portion, the outer dimensions of the compressor 42 are larger than those of the accumulator 44, and the compressor 42 has a compression mechanism inside. Therefore, the mass of the compressor 42 is larger than that of the accumulator 44 .

Further, in the present embodiment, the outdoor unit 20 is provided with an expansion valve 46 and a four-way valve 48 . The expansion valve 46 is an example of a throttle device that adjusts the pressure of the refrigerant. The expansion valve 46 adjusts the flow rate of the refrigerant and adjusts the pressure (reduces pressure) of the refrigerant flowing therein. The expansion valve 46 is, for example, an electronic expansion valve whose opening can be changed based on instructions from a control device (not shown). The four-way valve 48 is an example of a channel switching device that switches the direction of the coolant channel. The four-way valve 48 switches the flow direction of the refrigerant in the refrigerant circuit 30 between cooling operation and heating operation.

FIG. 2 is a schematic diagram showing the main internal configuration of the outdoor unit 20, and is a front view. As shown in FIG. 2 , in the present embodiment, a partition plate 22 is provided inside the housing 21 of the outdoor unit 20 . A partition plate 22 divides the inside of the housing 21 into a fan room 23 and a machine room 24 . The fan room 23 is provided with an outdoor heat exchanger 40 and a fan 41 . Air blower 41 is arranged to face outdoor heat exchanger 40 . The machine room 24 is provided with a compressor 42 , an accumulator 44 , and an electric component storage section 58 . The compressor 42 and the accumulator 44 are horizontally arranged side by side. The electrical component storage section 58 is formed in a box shape and stores electronic components and the like that perform processing such as power supply to each device. The electrical component storage section 58 is arranged above the compressor 42 and the accumulator 44 .

As shown in FIG. 2 , the outdoor unit 20 further includes a compressor heating section 52 , an accumulator heating section 54 , an outside air temperature sensor 56 and a heating control section 60 .

Compressor heating unit 52 is provided in compressor 42 and heats compressor 42 . In this embodiment, the compressor heating section 52 is arranged on the outer surface of the lower portion of the compressor 42 . This makes it easier to effectively heat the liquid refrigerant accumulated in the lower portion of the compressor 42 . The compressor heating section 52 is, for example, a crankcase heater, a belt heater, an induction heater, or a jacket heater. Further, the compressor heating section 52 may be configured by combining two or more of these heaters.

The accumulator heating unit 54 is provided in the accumulator 44 and heats the accumulator 44 . In this embodiment, the accumulator heating section 54 is arranged on the outer surface of the lower portion of the accumulator 44 . This makes it easier to effectively heat the liquid refrigerant stored in the accumulator 44 . The accumulator heating section 54 is, for example, a crankcase heater, a belt heater, an induction heater, or a jacket heater. Also, the accumulator heating section 54 may be configured by combining two or more of these heaters.

When the compressor heating section 52 and the accumulator heating section 54 are composed of the heaters described above, for example, the compressor heating section 52 may be configured such that a crankcase heater, a belt heater, or the like is simply wound around the lower portion of the compressor 42 . Since the configuration is such that the outer dimensions of the compressor 42 are increased, it is possible to suppress an increase in the external dimensions. The same applies to the accumulator heating part 54, and an increase in the outer dimensions of the accumulator 44 can be suppressed. Therefore, it is possible to prevent the size of the outdoor unit 20 from increasing due to the provision of the compressor heating section 52 and the accumulator heating section 54 .

An outside air temperature sensor 56 detects the temperature of outside air. In this embodiment, the outside air temperature sensor 56 is attached to the housing 21 on the rear side of the outdoor unit 20 . That is, the outside air temperature sensor 56 is arranged separately from the compressor 42 and the accumulator 44 . The outside air temperature sensor 56 is composed of, for example, a thermistor.

The heating control unit 60 controls the compressor heating unit 52 to heat the compressor 42 and the accumulator heating unit 54 to heat the accumulator 44 based on the detected temperature detected by the outside air temperature sensor 56 . In this embodiment, the heating control section 60 is housed in the electrical component housing section 58 . The heating control unit 60 is electrically connected to each of the compressor heating unit 52, the accumulator heating unit 54, and the outside air temperature sensor 56 via wiring (not shown).

FIG. 3 is a block diagram showing the functions of the heating control section 60. As shown in FIG. As shown in FIG. 3 , the heating control section 60 has an outside air temperature acquisition section 62 , an electricity supply control section 64 and a storage section 66 .

The outside air temperature acquisition unit 62 acquires the outside air temperature detected by the outside air temperature sensor 56 . The power supply control unit 64 controls power supply to the compressor heating unit 52 and power supply to the accumulator heating unit 54 based on the detected temperature of the outside air acquired by the outside air temperature acquisition unit 62 . In the present embodiment, the energization control unit 64 controls energization to the compressor heating unit 52 so that the amount of heating of the compressor 42 by the compressor heating unit 52 is constant. Similarly, the energization control unit 64 controls energization to the accumulator heating unit 54 so that the amount of heating of the accumulator 44 by the accumulator heating unit 54 is constant. More specifically, the energization control unit 64 controls the compressor so that the amount of heat generated per unit time when the heater constituting the compressor heating unit 52 generates heat during the energization of the compressor heating unit 52 is constant. It controls energization to the heating unit 52 . In addition, the energization control unit 64 controls the energization of the accumulator heating unit 54 so that the amount of heat generated per unit time when the heater constituting the accumulator heating unit 54 generates heat during the energization of the accumulator heating unit 54 is constant. do. The storage unit 66 stores the temperature acquired by the outside air temperature acquisition unit 62 and various parameters such as a first reference value TH1, which will be described later, that the power supply control unit 64 uses for control.

The heating control unit 60 is realized, for example, as a processing circuit having the hardware configuration shown in FIG. FIG. 4 is a diagram illustrating an example of a hardware configuration of a processing circuit; Each component constituting the heating control unit 60 is implemented by executing a program stored in the memory 72 by the processor 71 shown in FIG. 4, for example. Also, multiple processors and multiple memories may work together to achieve the above functions. Also, part of the functions of the heating control unit 60 may be implemented as an electronic circuit, and other parts may be realized using the processor 71 and the memory 72 .

Next, the operation of the air conditioner 1 according to Embodiment 1 will be described. First, the basic operation of the air conditioner 1 will be described with reference to FIG.

In the case of cooling operation, the refrigerant circuit 30 is configured such that the four-way valve 48 switches the flow path of the refrigerant as indicated by the solid line, and the high-temperature, high-pressure refrigerant flows through the outdoor heat exchanger 40 . That is, during the cooling operation, the refrigerant circulates through the compressor 42, the four-way valve 48, the outdoor heat exchanger 40, the expansion valve 46, the indoor heat exchanger 50, the four-way valve 48, the accumulator 44, and the compressor 42 in this order. .

The high-temperature and high-pressure gas refrigerant (gas state refrigerant) discharged from the compressor 42 flows into the outdoor heat exchanger 40 through the four-way valve 48 . In the outdoor heat exchanger 40, heat is exchanged between the gas refrigerant and the outside air, and the condensation heat of the refrigerant is released to the outside air. As a result, the refrigerant that has flowed into the outdoor heat exchanger 40 is condensed into a high-pressure liquid refrigerant (liquid state refrigerant). The high-pressure liquid refrigerant that has flowed out of the outdoor heat exchanger 40 flows into the expansion valve 46 and is decompressed to become a low-temperature, low-pressure two-phase refrigerant (refrigerant in a gas-liquid two-phase state). The low-temperature, low-pressure two-phase refrigerant flows into the indoor heat exchanger 50 . In the indoor heat exchanger 50, heat is exchanged between the two-phase refrigerant and the air in the air conditioning target space, and the two-phase refrigerant absorbs heat from the air and evaporates to become a low-pressure gas refrigerant. Along with this, the air in the air conditioning target space is cooled. Low-pressure gas refrigerant is drawn into the compressor 42 via the four-way valve 48 and the accumulator 44 . The refrigerant sucked into the compressor 42 is compressed into a high-temperature and high-pressure gas refrigerant. During the cooling operation, the above cycle is repeated.

In the case of heating operation, the refrigerant circuit 30 is configured such that the four-way valve 48 switches the flow path of the refrigerant as indicated by the dashed line, and the high-temperature, high-pressure refrigerant flows through the indoor heat exchanger 50 . That is, during heating operation, the refrigerant circulates through the compressor 42, the four-way valve 48, the indoor heat exchanger 50, the expansion valve 46, the outdoor heat exchanger 40, the four-way valve 48, the accumulator 44, and the compressor 42 in this order. .

The high-temperature, high-pressure gas refrigerant discharged from the compressor 42 flows through the four-way valve 48 into the indoor heat exchanger 50 . In the indoor heat exchanger 50, heat is exchanged between the gas refrigerant and the air in the air conditioning target space, and the heat of condensation of the refrigerant is released to the air in the air conditioning target space. As a result, the air in the air conditioning target space is heated, and the refrigerant that has flowed into the indoor heat exchanger 50 is condensed into a high-pressure liquid refrigerant. The liquid refrigerant that has flowed out of the indoor heat exchanger 50 flows into the expansion valve 46 , is decompressed, becomes a low-temperature, low-pressure two-phase refrigerant, and flows into the outdoor heat exchanger 40 . The two-phase refrigerant that has flowed into the outdoor heat exchanger 40 absorbs heat from the outside air in the outdoor heat exchanger 40 and evaporates to become a gas refrigerant. The gas refrigerant is sucked into the compressor 42 through the four-way valve 48 and the accumulator 44 and compressed into a high-temperature and high-pressure gas refrigerant. During heating operation, the above cycle is repeated.

Next, the heating control of the compressor 42 and the accumulator 44 to prevent the stagnation phenomenon of the refrigerant will be described with reference to FIGS. 5 to 7. FIG. 5 and 6 are flowcharts of heating control of the compressor 42 and the accumulator 44 in the outdoor unit 20. FIG. FIG. 7 is an example of a timing chart of heating control of the compressor 42 and the accumulator 44 in the outdoor unit 20. As shown in FIG. The heating control of the compressor 42 and the accumulator 44 described below is performed while the compressor 42 is stopped.

First, the outside air temperature acquisition unit 62 of the heating control unit 60 acquires the outside air temperature detected by the outside air temperature sensor 56 as the detected temperature (step ST1). The detected temperature acquired by the outside temperature acquisition unit 62 is stored in the storage unit 66 . Next, the energization control unit 64 determines whether the compressor heating unit 52 is in a non-energized state (OFF state) or energized state (ON state) by the energization control unit 64. (Step ST2). That is, it is determined whether or not the compressor heating section 52 is not heating the compressor 42 .

When the compressor heating unit 52 is in the OFF state, the energization control unit 64 reads the detected temperature and the first reference value TH1 acquired by the outside air temperature acquisition unit 62 from the storage unit 66, and the detected temperature reaches the first reference value TH1. It is determined whether or not (step ST3). Here, the first reference value TH<b>1 is a temperature value that is preset in consideration of a situation where refrigerant stagnation occurs in the compressor 42 , and is stored in the storage unit 66 . When the detected temperature is equal to or lower than the first reference value TH1, the energization control section 64 energizes and turns on the compressor heating section 52, and causes the compressor heating section 52 to start heating the compressor 42 (step ST4). If the detected temperature is higher than the first reference value TH1, it is not necessary to heat the compressor 42, so the process directly returns to step ST1.

Following step ST4, the energization control unit 64 reads the detected temperature and the second reference value TH2 acquired by the outside air temperature acquisition unit 62 from the storage unit 66, and determines whether or not the detected temperature is equal to or lower than the second reference value TH2. Determine (step ST5). Here, the second reference value TH<b>2 is a temperature value that is preset in consideration of the situation where the refrigerant stagnation phenomenon occurs in the accumulator 44 , and is stored in the storage unit 66 . Also, the second reference value TH2 is a value smaller than the first reference value TH1. If the detected temperature is equal to or lower than the second reference value TH2, the power supply control unit 64 turns on the accumulator heating unit 54 and causes the accumulator heating unit 54 to start heating the accumulator 44 (step ST6). Then, the process returns to step ST1. If the detected temperature is higher than the second reference value TH2, it is not necessary to heat the accumulator 44, so the process directly returns to step ST1.

Next, in step ST2, when the compressor heating unit 52 is in the ON state instead of the OFF state, that is, once the detected temperature becomes equal to or lower than the first reference value TH1, the compressor heating unit 52 turns the compressor 42 on. A case of being in a heating state will be described. In this case, the energization control unit 64 determines whether the accumulator heating unit 54 is not energized (OFF state) or energized (ON state) by the energization control unit 64 ( step ST7). That is, it is determined whether or not the accumulator heating unit 54 is not heating the accumulator 44 .

When the accumulator heating unit 54 is in the OFF state, the energization control unit 64 reads the detected temperature and the second reference value TH2 acquired by the outside air temperature acquisition unit 62 from the storage unit 66, and the detected temperature is It is determined whether or not it is equal to or less than the second reference value TH2 (step ST8). If the detected temperature is equal to or lower than the second reference value TH2, the energization control unit 64 energizes and turns on the accumulator heating unit 54, starts heating the accumulator 44 by the accumulator heating unit 54 (step ST9), and proceeds to step ST1. return. If the detected temperature is higher than the second reference value TH2, the process proceeds to step ST12, which will be described later.

In step ST7, if the accumulator heating unit 54 is in the ON state instead of the OFF state, that is, once the detected temperature is equal to or lower than the second reference value TH2, and the accumulator heating unit 54 is heating the accumulator 44. If there is, the energization control unit 64 reads the detected temperature and the third reference value TH3 obtained by the outside air temperature obtaining unit 62 from the storage unit 66, and determines whether or not the detected temperature is equal to or higher than the third reference value TH3 ( step ST10). Here, the third reference value TH3 is a preset temperature value similar to the second reference value TH2 and is stored in the storage unit 66 . Also, the third reference value TH3 is a value larger than the second reference value TH2. When the detected temperature is equal to or higher than the third reference value TH3, the energization control unit 64 stops energizing the accumulator heating unit 54, turns off the accumulator heating unit 54, and stops heating the accumulator 44 by the accumulator heating unit 54 ( step ST11). If the detected temperature is lower than the third reference value TH3, it is necessary to continue heating the accumulator 44, so the process directly returns to step ST1.

Following step ST11, the energization control unit 64 reads out the detected temperature and the fourth reference value TH4 acquired by the outside air temperature acquiring unit 62 from the storage unit 66, and determines whether or not the detected temperature is equal to or higher than the fourth reference value TH4. Determine (step ST12). Here, the fourth reference value TH<b>4 is a preset temperature value similar to the first reference value, and is stored in the storage unit 66 . Also, the fourth reference value TH4 is a value greater than both the first reference value TH1 and the third reference value TH3. When the detected temperature is equal to or higher than the fourth reference value TH4, the energization control unit 64 stops energizing the compressor heating unit 52 to turn off the compressor heating unit 52, and the compressor 42 is heated by the compressor heating unit 52. is stopped (step ST13). Then, the process returns to step ST1. If the detected temperature is lower than the fourth reference value TH4, it is necessary to continue heating the compressor 42, so the process directly returns to step ST1.

The heating control unit 60 controls the heating of the compressor 42 and the accumulator 44 according to the temperature of the outside air according to the flow described above.

FIG. 7 is an example of a timing chart when heating control of the compressor 42 and the accumulator 44 is performed according to the flow described above. The horizontal axis of FIG. 7 indicates the flow of time. The vertical axis of FIG. 7 indicates, from the top, changes in the detected temperature, turning on and off of the compressor heating section 52, and turning on and off of the accumulator heating section .

With both the compressor heating section 52 and the accumulator heating section 54 turned off, the outside air temperature drops, the temperature detected by the outside air temperature sensor 56 drops, and at time t1 the detected temperature becomes equal to or lower than the first reference value TH1. In this case, the compressor heating section 52 is turned on, and heating of the compressor 42 by the compressor heating section 52 is started. When the detected temperature further drops and becomes equal to or lower than the second reference value TH2 at time t2, the accumulator heating section 54 is turned on, and heating of the accumulator 44 by the accumulator heating section 54 is started. After a while, the temperature of the outside air rises, and when the detected temperature becomes equal to or higher than the third reference value TH3 at time t3, the accumulator heating section 54 is turned off, and heating of the accumulator 44 by the accumulator heating section 54 is stopped. When the detected temperature further increases and becomes equal to or higher than the fourth reference value TH4 at time t4, the compressor heating unit 52 is turned off, and heating of the compressor 42 by the compressor heating unit 52 is stopped.

As shown in FIG. 7, the first reference value TH1 is greater than the second reference value TH2, and the fourth reference value TH4 is greater than the third reference value TH3, so that the compressor heating section 52 is turned on to compress the air. The time during which the accumulator 42 is heated (period from time t1 to time t4) is longer than the time during which the accumulator heating unit 54 is turned on and the accumulator 44 is heated (period from time t2 to time t3). . If the heating time of the compressor 42 and the heating time of the accumulator 44 are the same, the heat capacity of the accumulator 44 is smaller than the heat capacity of the compressor 42, so the accumulator 44 may be overheated. In contrast, in the present embodiment, the heating time of the accumulator 44 is shorter than the heating time of the compressor 42 as described above, so that the accumulator 44 can be prevented from being heated more than necessary, thereby reducing power consumption. can be made

Further, since the second reference value TH2 is smaller than the first reference value TH1, the heating of the accumulator 44 is started after the heating of the compressor 42 is started. If the heating of the accumulator 44 is started first, the refrigerant vaporized in the accumulator 44 by heating may move to the compressor 42, which is not yet heated and has a low temperature, and condense again. In contrast, in the present embodiment, heating of the compressor 42 is started first as described above, so that the refrigerant vaporized in the accumulator 44 can be prevented from being recondensed in the compressor 42 .

Furthermore, since the fourth reference value TH4 is greater than the third reference value TH3, the heating of the compressor 42 is stopped after the heating of the accumulator 44 is stopped. If the heating of the compressor 42 is stopped first, the temperature of the accumulator 44 is continued while the temperature of the accumulator 44 is continued while the temperature of the compressor 42 is not heated. may be lower than In this case, there is a possibility that the vaporized refrigerant in the accumulator 44 moves to the compressor 42 with a lower temperature and condenses again. In contrast, in the present embodiment, the heating of the accumulator 44 is stopped first as described above, so that the refrigerant vaporized in the accumulator 44 can be prevented from recondensing in the compressor 42 .

In addition, since the first reference value TH1 and the fourth reference value TH4 are different values, and the fourth reference value TH4 is greater than the first reference value TH1, the heating of the compressor 42 by the compressor heating section 52 is A hysteresis width is provided between the temperature at which it is started and the temperature at which it is stopped. Similarly, since the second reference value TH2 and the third reference value TH3 are different values, and the third reference value TH3 is greater than the second reference value TH2, the accumulator heating section 54 starts heating the accumulator 44. A hysteresis width is provided between the starting temperature and the stopping temperature. Since the hysteresis width is provided in this manner, the compressor heating section 52 and the accumulator heating section 54 are prevented from repeatedly turning on and off excessively, and the measurement error of the outside air temperature sensor 56 is absorbed to achieve stable control. It can be carried out.

As an example, the first reference value TH1, the second reference value TH2, the third reference value TH3, and the fourth reference value TH4 can be set as follows. First, the first reference value TH1 is set based on the results of a test for determining the temperature of the outside air at which the compressor heating section 52 is turned on. Specifically, the stagnation amount of the refrigerant in the compressor 42 when a malfunction occurs in the compressor 42 due to the refrigerant stagnation phenomenon is calculated in advance from the shape of the compressor 42 and the like. Also, the amount of refrigerant stagnation in the compressor 42 with respect to the temperature of the outside air is measured, and the relationship between the temperature of the outside air and the amount of refrigerant stagnation is obtained. The temperature of the outside air at which the compressor heating section 52 is turned on is obtained based on the amount of refrigerant stagnation causing the problem and the relationship between the temperature of the outside air and the amount of refrigerant stagnation, and that temperature is used as the first reference value. Set as TH1. Further, the fourth reference value TH4, which is the outside air temperature at which the compressor heating unit 52 is turned off, is set with reference to the standard heating capacity conditions.

The second reference value TH2, which is the temperature of the outside air at which the accumulator heating section 54 is turned on, and the third reference value TH3, which is the temperature of the outside air at which the accumulator heating section 54 is turned off, are calculated based on a comparison of the heat capacities of the compressor 42 and the accumulator 44. be. Specifically, assuming that the amount of refrigerant stagnation is proportional to the heat capacity, the difference in heat capacity between the compressor 42 and the accumulator 44 is determined from the relationship between the measured outside air temperature in the compressor 42 and the amount of refrigerant stagnation. , the relationship between the temperature of the outside air and the amount of refrigerant accumulated in the accumulator 44 is calculated.

When the compressor 42 is heated and the accumulator 44 is not heated, the accumulator 44 is relatively at the lowest temperature in the refrigerant circuit 30 of the air conditioner 1, and the refrigerant may accumulate in the accumulator 44. have a nature. In this case, if a state occurs in which the accumulator 44 is filled with refrigerant, the refrigerant in the accumulator 44 may overflow the accumulator 44 when the compressor 42 is subsequently started, and liquid refrigerant may flow into the compressor 42 . . This may cause the compressor 42 to malfunction. In order to prevent this, heating of the accumulator 44 is started when the amount of refrigerant accumulated in the accumulator 44 is such that a problem occurs in the compressor 42 . That is, based on the accumulated amount of refrigerant and the calculated relationship between the temperature of the outside air and the amount of accumulated refrigerant in the accumulator 44, the temperature of the outside air at which the accumulator heating unit 54 is turned on is obtained. 2 is set as a reference value TH2.

The outside air temperature at which the accumulator heating unit 54 is turned off is set, for example, to the outside air temperature at which the amount of refrigerant accumulated in the accumulator 44 is about half the amount of refrigerant accumulated in the compressor 42 that causes a problem. be. That is, the outside air for turning off the accumulator heating unit 54 is based on the amount of about half of the accumulated amount of refrigerant that causes this problem and the calculated relationship between the temperature of the outside air in the accumulator 44 and the amount of accumulated refrigerant. is obtained, and the obtained temperature is set as the third reference value TH3.

As an example of values set based on the above, the first reference value TH1 is 0°C, the second reference value TH2 is -1°C, the third reference value TH3 is 7°C, and the fourth reference value TH4 is 8°C. .

As described above, the outdoor unit 20 of the air conditioner 1 according to the present embodiment includes the outdoor heat exchanger 40 that exchanges heat between the outside air and the refrigerant, and the compressor that sucks, compresses, and discharges the refrigerant. a compressor 42, an accumulator 44 that is provided on the suction side of the compressor 42 and stores liquid refrigerant, a compressor heating unit 52 that is provided in the compressor 42 and heats the compressor 42, and is provided in the accumulator 44, The temperature detected by the accumulator heating unit 54 that heats the accumulator 44 and the outside air temperature sensor 56 that detects the temperature of the outside air is acquired, and the compressor heating unit 52 is controlled to heat the compressor 42, and the accumulator heating unit 54 and a heating control unit 60 that controls heating of the accumulator 44 based on the detected temperature.

With such a configuration, when the compressor 42 and the accumulator 44 are heated in order to prevent the stagnation phenomenon of the refrigerant, the heating control unit 60 controls the compressor heating unit 52 to heat the compressor 42, Control for causing the heating unit 54 to heat the accumulator 44 is performed based on the detected temperature detected by the outside air temperature sensor 56 . Thus, since the heating control of the compressor 42 and the accumulator 44 is performed using the temperature detected by the outside air temperature sensor 56, there is no need to provide a pressure sensor or the like, so costs can be reduced. In addition, since the outside air temperature sensor 56 is already installed in a general air conditioner and can be used, an increase in cost can be suppressed. Therefore, heating control of the compressor 42 and the accumulator 44 can be performed at low cost.

Further, when the detected temperature becomes equal to or lower than the first reference value TH1, the heating control unit 60 causes the compressor heating unit 52 to start heating the compressor 42, and heats the compressor 42 when the detected temperature is lower than the first reference value TH1. 2 When it becomes equal to or less than the reference value TH2, heating of the accumulator 44 by the accumulator heating section 54 is started. With such a configuration, since the second reference value TH2 is smaller than the first reference value TH1, the heating of the accumulator 44 is started after the heating of the compressor 42 is started. As a result, the temperature of the compressor 42 can be made higher than the temperature of the accumulator 44 , so that the refrigerant vaporized in the accumulator 44 can be prevented from recondensing in the compressor 42 .

The heating control unit 60 controls the accumulator heating unit 54 to heat the accumulator 44 when the detected temperature reaches or exceeds a third reference value TH3, which is larger than the second reference value TH2, while the accumulator heating unit 54 is heating the accumulator 44. is stopped, and the detected temperature becomes equal to or higher than a fourth reference value TH4, which is higher than both the first reference value TH1 and the third reference value TH3, while the compressor heating unit 52 is heating the compressor 42. In this case, the heating of the compressor 42 by the compressor heating unit 52 is stopped.

With such a configuration, since the third reference value TH3 is greater than the fourth reference value TH4, the heating of the compressor 42 is stopped after the heating of the accumulator 44 is stopped. This prevents the temperature of the compressor 42 from becoming lower than the temperature of the accumulator 44 , thereby preventing the refrigerant vaporized in the accumulator 44 from recondensing in the compressor 42 . In addition, since the fourth reference value TH4 is greater than the first reference value TH1, a hysteresis width is provided between the temperature at which the heating of the compressor 42 by the compressor heating section 52 is started and the temperature at which it is stopped. Also, since the third reference value TH3 is greater than the second reference value TH2, a hysteresis width is provided between the temperature at which the accumulator heating section 54 starts heating the accumulator 44 and the temperature at which it stops. Since the hysteresis width is provided in this manner, the compressor heating section 52 and the accumulator heating section 54 are prevented from repeatedly turning on and off excessively, and the measurement error of the outside air temperature sensor 56 is absorbed to achieve stable control. It can be carried out.

Each of the compressor heating section 52 and the accumulator heating section 54 is composed of at least one of a crankcase heater, a belt heater, an induction heater, and a jacket heater. With such a configuration, for example, by winding these heaters around the outer circumferences of the compressor 42 and the accumulator 44, the compressor heating section 52 and the accumulator heating section 54 can be easily installed in the compressor 42 and the accumulator 44, respectively. .

When the compressor 42 is stopped, the heating control unit 60 controls the compressor heating unit 52 to heat the compressor 42 and the accumulator heating unit 54 to heat the accumulator 44 based on the detected temperature. to implement. Such a configuration allows heating of the compressor 42 and heating of the accumulator 44 while the compressor 42 is stopped. Therefore, when the operation start of the air conditioner 1 is instructed to start the compressor 42, it is not necessary to wait for the time to heat the compressor 42 and the accumulator 44 in order to prevent the stagnation phenomenon of the refrigerant. , can be started immediately.

Further, the method for controlling the outdoor unit 20 of the air conditioner 1 according to the present embodiment includes the outdoor heat exchanger 40 that exchanges heat between the outside air and the refrigerant, and the compressor 42 that sucks, compresses, and discharges the refrigerant. , an accumulator 44 that is provided on the suction side of the compressor 42 and stores liquid refrigerant, a compressor heating unit 52 that is provided in the compressor 42 and heats the compressor 42, and an accumulator 44 that is provided in the accumulator 44 and a heating control unit 60 for controlling the compressor heating unit 52 and the accumulator heating unit 54. A method for controlling the outdoor unit 20 of the air conditioner 1, wherein the heating control unit 60 a step of obtaining a detected temperature detected by an outside air temperature sensor 56 for detecting the outside air temperature; a step of causing the heating control unit 60 to heat the compressor 42 based on the detected temperature; and a step in which the control unit 60 causes the accumulator heating unit 54 to heat the accumulator 44 based on the detected temperature.

As a result, when the compressor 42 and the accumulator 44 are heated in order to prevent the stagnation phenomenon of the refrigerant, the heating control unit 60 causes the compressor heating unit 52 to perform compression based on the detected temperature detected by the outside air temperature sensor 56 . The accumulator 42 is heated, and the accumulator heater 54 is caused to heat the accumulator 44 based on the sensed temperature. Thus, since the heating control of the compressor 42 and the accumulator 44 is performed using the temperature detected by the outside air temperature sensor 56, there is no need to provide a pressure sensor or the like, so costs can be reduced. In addition, since the outside air temperature sensor 56 is already installed in a general air conditioner and can be used, an increase in cost can be suppressed. Therefore, heating control of the compressor 42 and the accumulator 44 can be performed at low cost.

In the above description, the outside air temperature acquisition unit 62 acquires the outside air temperature detected by the outside air temperature sensor 56, but the invention is not limited to this. For example, the outside air temperature acquisition unit 62 may acquire the outside air temperature detected by another temperature sensor provided around the outdoor unit 20 . Further, for example, when a plurality of outdoor units are collectively arranged, the outside air temperature acquisition unit 62 may acquire the outside air temperature detected by the outside air temperature sensor of another outdoor unit.

Moreover, although the air conditioner 1 is provided with the four-way valve 48 and has a configuration in which both the cooling operation and the heating operation are possible, the present invention is not limited to this. For example, the air conditioner 1 may not be provided with the four-way valve 48, and the air conditioner 1 may be used exclusively for heating operation.

Also, although the expansion valve 46 is provided in the outdoor unit 20, the present invention is not limited to this. For example, the expansion valve 46 may be provided in the indoor unit 10 . Also, the function of the heating control unit 60 may be performed by a control device (not shown) that controls the driving of the compressor 42, the adjustment of the opening degree of the expansion valve 46, the switching operation of the four-way valve 48, and the like.

Embodiment 2.
Next, Embodiment 2 will be described with reference to FIG. FIG. 8 is an example of a timing chart of heating control of the compressor 42 and the accumulator 44 in the outdoor unit 20 according to this embodiment. The horizontal axis of FIG. 8 indicates the flow of time. The vertical axis in FIG. 8 indicates, from top to bottom, change in detected temperature, turning on and off of compressor heating section 52, change in heating amount of compressor heating section 52, turning on and off of accumulator heating section 54, and accumulator heating section. 54 shows changes in the amount of heating. In this embodiment, the description of the same parts as in the first embodiment will be omitted.

In the first embodiment, the energization control unit 64 of the heating control unit 60 controls the compressor so that the amount of heating of the compressor 42 by the compressor heating unit 52 and the amount of heating of the accumulator 44 by the accumulator heating unit 54 are constant. Although the energization of the heating portion 52 and the accumulator heating portion 54 is controlled, the present invention is not limited to this. In the present embodiment, the heating control unit 60 changes the heating amount of the compressor heating unit 52 and the heating amount of the accumulator heating unit 54 according to the detected temperature detected by the outside air temperature sensor 56 . Specifically, when the detected temperature is low, the heating control unit 60 increases the heating amount of the compressor heating unit 52 and the heating amount of the accumulator heating unit 54 .

The heating amount of the compressor heating section 52 can be changed, for example, by changing the amount of heat generated when the heater constituting the compressor heating section 52 generates heat. Specifically, the energization control unit 64 changes the voltage applied to the heater while the compressor heating unit 52 is energized to change the amount of heat generated by the heater, thereby changing the heating amount of the compressor heating unit 52. be able to. Similarly, the energization control unit 64 can change the voltage applied to the heater while the accumulator heating unit 54 is energized, thereby changing the amount of heat generated by the heater, thereby changing the heating amount of the accumulator heating unit 54 .

For example, as shown in FIG. 8, the detected temperature becomes equal to or lower than the first reference value TH1 at time t1, and the compressor heating section 52 is turned on. At this time, the compressor heating unit 52 heats the compressor 42 with a heating amount QC1. When the outside air temperature drops and the detected temperature becomes equal to or lower than the second reference value TH2 at time t2, the accumulator heating section 54 is turned on. At this time, the accumulator heating unit 54 heats the accumulator 44 with a heating amount QA1. When the temperature of the outside air further decreases and the detected temperature becomes equal to or lower than the temperature TP1 which is lower than the second reference value TH2 at time t5, the power supply control unit 64 heats the heating amount of the compressor heating unit 52 from the heating amount QC1. The heating amount is changed to a heating amount QC2 larger than the heating amount QC1, and the heating amount of the accumulator heating unit 54 is changed from the heating amount QA1 to the heating amount QA2 larger than the heating amount QA1. After a while after that, the temperature of the outside air rises, and when the detected temperature reaches a temperature TP2 which is higher than the temperature TP1 and lower than the third reference value TH3 at time t6, the energization control unit 64 turns on the compressor heating unit 52. The heating amount is changed from the heating amount QC2 to the heating amount QC1, and the heating amount of the accumulator heating section 54 is changed from the heating amount QA2 to the heating amount QA1. When the temperature of the outside air further rises and the detected temperature becomes equal to or higher than the third reference value TH3 at time t3, the accumulator heating section 54 is turned off and the heating amount of the accumulator heating section 54 becomes zero. Then, when the detected temperature becomes equal to or higher than the fourth reference value TH4 at time t4, the compressor heating unit 52 is turned off and the heating amount of the compressor heating unit 52 becomes zero.

In the outdoor unit 20 according to the present embodiment, the heating control unit 60 changes the heating amount of the compressor heating unit 52 and the heating amount of the accumulator heating unit 54 according to the detected temperature. With such a configuration, for example, when the outside air temperature is lower than the first reference value TH1 or the second reference value TH2 but is relatively high, the heating amount of the compressor heating section 52 and the heating amount of the accumulator heating section 54 are By reducing , the compressor 42 and the accumulator 44 can be prevented from being heated more than necessary, and power consumption can be reduced. On the other hand, when the temperature of the outside air is relatively low, by increasing the heating amount of the compressor heating section 52 and the heating amount of the accumulator heating section 54, the refrigerant stagnation state can be quickly eliminated.

In the above description, the energization control unit 64 changes the amount of heating of the compressor heating unit 52 and the amount of heating of the accumulator heating unit 54 in stages in response to changes in the detected temperature, but this is not the only option. do not have. The energization control unit 64 may continuously change the heating amount of the compressor heating unit 52 and the heating amount of the accumulator heating unit 54 in response to changes in the detected temperature.

In addition, although the energization control unit 64 changes both the amount of heating of the compressor heating unit 52 and the amount of heating of the accumulator heating unit 54 in response to changes in the detected temperature, only one of them is changed. may

Embodiment 3.
Next, Embodiment 3 will be described with reference to FIG. FIG. 9 is an example of a timing chart of heating control of the compressor 42 and the accumulator 44 in the outdoor unit 20 in this embodiment. The horizontal axis of FIG. 9 indicates the flow of time. The vertical axis in FIG. 9 indicates, from the top, changes in the detected temperature, turning on and off of the compressor heating section 52, and turning on and off of the accumulator heating section . Note that descriptions of portions of the present embodiment that are the same as those of the first and second embodiments will be omitted.

In the first embodiment, when the compressor heating unit 52 is caused to heat the compressor 42 , the heating control unit 60 always turns on the heater constituting the compressor heating unit 52 , and causes the accumulator heating unit 54 to heat the accumulator 44 . Although the heater constituting the accumulator heating unit 54 is always turned on in the case of enabling the heating, the present invention is not limited to this. In the present embodiment, when the compressor heating unit 52 is caused to heat the compressor 42 , the heating control unit 60 repeatedly turns on and off the compressor heating unit 52 and causes the accumulator heating unit 54 to heat the accumulator 44 . , the accumulator heating unit 54 is repeatedly turned on and off. Further, the heating control unit 60 changes the ON time and OFF time of the compressor heating unit 52 and the ON time and OFF time of the accumulator heating unit 54 in accordance with the detected temperature. Specifically, when the detected temperature is low, the heating control unit 60 makes the ON time of each of the compressor heating unit 52 and the accumulator heating unit 54 longer than the OFF time.

For example, as shown in FIG. 9, the detected temperature becomes equal to or lower than the first reference value TH1 at time t1, and heating of the compressor 42 by the compressor heating section 52 is started. In this case, the energization control unit 64 causes the compressor heating unit 52 to heat the compressor 42 while controlling the energization of the compressor heating unit 52 to periodically turn on and off the compressor heating unit 52 . Here, the ON time and the OFF time of the compressor heating section 52 are set to the same length. When the temperature of the outside air drops and the detected temperature becomes equal to or lower than the second reference value TH2 at time t2, heating of the accumulator 44 by the accumulator heating section 54 is started. In this case, the energization control unit 64 causes the accumulator heating unit 54 to heat the accumulator 44 while controlling the energization to the accumulator heating unit 54 to periodically turn on and off the accumulator heating unit 54 . Here, the ON time and OFF time of the accumulator heating unit 54 are the same length.

When the temperature of the outside air further drops and the detected temperature becomes equal to or lower than the temperature TP1 at time t5, the energization control unit 64 makes the ON time of the compressor heating unit 52 longer than the OFF time, and The compressor heating section 52 is made to heat the compressor 42 while periodically turning on and off the heating section 52 . At the same time, the energization control unit 64 makes the ON time of the accumulator heating unit 54 longer than the OFF time, and periodically repeats the ON and OFF of the accumulator heating unit 54 to supply the accumulator 44 to the accumulator heating unit 54 . let it heat up. After a while, the temperature of the outside air rises, and when the detected temperature becomes equal to or higher than the temperature TP2 at time t6, the energization control unit 64 sets the ON time and OFF time of the compressor heating unit 52 to be the same. , the compressor heating unit 52 is caused to heat the compressor 42 while periodically turning on and off the compressor heating unit 52 . At the same time, the energization control unit 64 sets the ON time and the OFF time of the accumulator heating unit 54 to be the same, and cyclically repeats the ON and OFF of the accumulator heating unit 54 to supply the accumulator 44 to the accumulator heating unit 54 . is heated.

When the outside air temperature further rises and the detected temperature becomes equal to or higher than the third reference value TH3 at time t3, the energization control unit 64 causes the accumulator heating unit 54 to stop heating the accumulator 44 . Then, when the detected temperature becomes equal to or higher than the fourth reference value TH4 at time t4, the energization control unit 64 stops heating of the compressor 42 by the compressor heating unit 52 .

In the outdoor unit 20 according to the present embodiment, when the compressor heating unit 52 is caused to heat the compressor 42 , the heating control unit 60 repeatedly turns the compressor heating unit 52 on and off, and the accumulator heating unit 54 When the accumulator 44 is heated, the accumulator heating section 54 is repeatedly turned on and off, and the ON time and OFF time of the compressor heating section 52 and the ON time and OFF time of the accumulator heating section 54 are set to the detection temperature. change accordingly. With such a configuration, compared to the case where each of the compressor heating section 52 and the accumulator heating section 54 is always on, the ON time is shortened, so power consumption can be reduced. Further, for example, when the temperature of the outside air is relatively high, the off time of the compressor heating section 52 and the accumulator heating section 54 is lengthened, thereby heating the compressor 42 and the accumulator 44 more than necessary. can be suppressed, and power consumption can be reduced. When the temperature of the outside air is relatively low, the ON time of each of the compressor heating section 52 and the accumulator heating section 54 is lengthened to appropriately heat the compressor 42 and the accumulator 44 while suppressing power consumption. By doing so, the stagnation state of the refrigerant can be eliminated.

In the above description, the energization control unit 64 changes the ON time and OFF time of each of the compressor heating unit 52 and the accumulator heating unit 54 step by step according to changes in the detected temperature. However, it is not limited to this. The energization control unit 64 may continuously change the ON time and OFF time of each of the compressor heating unit 52 and the accumulator heating unit 54 in response to changes in the detected temperature.

Moreover, although the energization control unit 64 repeats both turning on and off of the compressor heating unit 52 and turning on and off of the accumulator heating unit 54, the present invention is not limited to this. The energization control unit 64 may repeat turning on and off only one of the compressor heating unit 52 and the accumulator heating unit 54 . In addition, the energization control unit 64 changes the on-time and off-time of the compressor heating unit 52 and the on-time and off-time of the accumulator heating unit 54 in response to the detected temperature. do not have. The energization control unit 64 may change the ON time and OFF time of only one of the compressor heating unit 52 and the accumulator heating unit 54 according to the detected temperature.

It should be noted that appropriate combinations, modifications, and omissions of the embodiments are also included within the scope of the technical ideas shown in the embodiments.

According to the present disclosure, compressor and accumulator heating control can be implemented at low cost.

1 air conditioner, 10 indoor unit, 20 outdoor unit, 21 housing, 22 partition plate, 23 blower room, 24 machine room, 30 refrigerant circuit, 31 refrigerant pipe, 40 outdoor heat exchanger, 42 compressor, 44 accumulator, 46 expansion valve (throttling device), 48 four-way valve, 50 indoor heat exchanger, 52 compressor heating unit, 54 accumulator heating unit, 56 outside air temperature sensor, 58 electrical component storage unit, 60 heating control unit, 62 outside air temperature acquisition unit , 64 energization control unit, 66 storage unit, 71 processor, 72 memory, QA1, QA2, QC1, QC2 heating amount, TH1 first reference value, TH2 second reference value, TH3 third reference value, TH4 fourth reference value, TP1, TP2 temperature.

Claims (8)

an outdoor heat exchanger that exchanges heat between the outside air and the refrigerant;
a compressor that sucks in, compresses, and discharges the refrigerant;
an accumulator provided on the suction side of the compressor and storing the liquid refrigerant;
a compressor heating unit provided in the compressor for heating the compressor;
an accumulator heating unit provided in the accumulator and heating the accumulator;
Acquiring the detected temperature detected by the outside air temperature sensor for detecting the temperature of the outside air, controlling the compressor heating unit to heat the compressor, and controlling the accumulator heating unit to heat the accumulator. a temperature-based heating controller;
with
The heating control unit
starting heating of the compressor by the compressor heating unit when the detected temperature is equal to or lower than a first reference value;
An outdoor unit of an air conditioner, wherein the accumulator heating section starts heating the accumulator when the detected temperature becomes equal to or lower than a second reference value that is lower than the first reference value. The heating control unit
stopping heating of the accumulator by the accumulator heating unit when the detected temperature reaches or exceeds a third reference value that is larger than the second reference value while the accumulator heating unit is heating the accumulator;
When the detected temperature becomes equal to or higher than a fourth reference value that is greater than both the first reference value and the third reference value while the compressor heating unit is heating the compressor, the compressor The outdoor unit of an air conditioner according to claim 1 , wherein the heating of the compressor by a heating unit is stopped. 3. The air conditioner according to claim 1, wherein the heating control unit changes at least one of a heating amount of the compressor heating unit and a heating amount of the accumulator heating unit according to the detected temperature. Equipment outdoor unit. Each of the compressor heating section and the accumulator heating section comprises at least one of a crankcase heater, a belt heater, an induction heater and a jacket heater. The outdoor unit of the air conditioner according to 1. The heating control unit
When the compressor heating unit is caused to heat the compressor, the compressor heating unit is repeatedly turned on and off,
When the accumulator heating unit is caused to heat the accumulator, the accumulator heating unit is repeatedly turned on and off,
5. The apparatus according to any one of claims 1 to 4, wherein the ON time and OFF time of the compressor heating section and the ON time and OFF time of the accumulator heating section are changed in accordance with the detected temperature. The outdoor unit of the described air conditioner. When the compressor is stopped, the heating control unit controls the compressor heating unit to heat the compressor and the accumulator heating unit to heat the accumulator to the detected temperature. The outdoor unit for an air conditioner according to any one of claims 1 to 5, which is implemented based on the above. The outdoor unit of the air conditioner according to any one of claims 1 to 6;
an indoor unit having an indoor heat exchanger that exchanges heat between the refrigerant and the air in the space to be air-conditioned;
and a throttle device that adjusts the pressure of the refrigerant,
An air conditioner, wherein a refrigerant circuit is configured by connecting the accumulator, the compressor, the outdoor heat exchanger, the throttle device, and the indoor heat exchanger via refrigerant pipes. An outdoor heat exchanger that exchanges heat between the outside air and the refrigerant, a compressor that sucks, compresses and discharges the refrigerant, an accumulator that is provided on the suction side of the compressor and stores the liquid refrigerant,
A compressor heating unit provided in the compressor for heating the compressor, an accumulator heating unit provided in the accumulator for heating the accumulator, and a heating control for controlling the compressor heating unit and the accumulator heating unit A method for controlling an outdoor unit of an air conditioner, comprising:
a step in which the heating control unit acquires a detected temperature detected by an outside air temperature sensor that detects the temperature of the outside air;
a step in which the heating control unit causes the compressor heating unit to heat the compressor when the detected temperature is equal to or lower than a first reference value;
a step in which the heating control unit causes the accumulator heating unit to heat the accumulator when the detected temperature becomes equal to or lower than a second reference value that is smaller than the first reference value;
A control method for an outdoor unit of an air conditioner.

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