JP7280482B2 - refrigeration cycle equipment - Google Patents

Description

A refrigeration cycle device that heats the compressor while the compressor is stopped.

In the refrigeration cycle apparatus, when the temperature is low and the compressor is stopped, the liquid refrigerant dissolves in the oil stored in the compressor, resulting in a decrease in oil viscosity. In order to deal with this problem, a heater is attached to the compressor to heat the stopped compressor (Patent Document 1 (Japanese Patent Application Laid-Open No. 2010-65958)).

Conventionally, such heating of the compressor has basically been performed while the compressor is stopped or before operation is started, based on the absolute value of the outside temperature or changes in the outside temperature. rice field. However, if the compressor continues to operate at low speed for a long period of time during inverter control, refrigerant with a low degree of superheat or low dryness is sucked into the compressor, and a large amount of liquid refrigerant dissolves in the compressor oil. can occur. In this specification, such a state in which the degree of superheat or dryness of the refrigerant is small is called a wet state, and operation of the compressor in which the refrigerant sucked into the compressor is in a wet state is called wet operation. More precisely, wet operation refers to a state in which the dryness of the refrigerant sucked into the compressor is less than 1 or the degree of superheat of the refrigerant sucked into the compressor is a predetermined value or less in the operation of the refrigeration cycle device. .

A refrigeration cycle apparatus according to a first aspect includes a compressor, a radiator, an evaporator, and a controller. The compressor compresses refrigerant. The radiator cools the refrigerant. The evaporator heats the refrigerant. The controller controls the compressor. After stopping the compressor, the control unit performs first heating control to heat the stopped compressor.

Since the refrigeration cycle device of the first aspect performs the first heating control to heat the compressor continuously after stopping the compressor, it is possible to reduce the concentration of the liquid refrigerant dissolved in the oil of the compressor.

The refrigeration cycle device of the second aspect is the refrigeration cycle device of the first aspect, wherein the control unit determines whether or not to perform the first heating control based on the index. The index is an index relating to the degree of superheat or dryness of the refrigerant sucked into the compressor before or after stopping the compressor.

Since the refrigeration cycle device of the second aspect performs the first heating control based on the index regarding the moist state of the refrigerant before or after stopping the compressor, there is a possibility that a large amount of liquid refrigerant is dissolved in the oil of the compressor. is high, the concentration of the liquid refrigerant dissolved in the compressor oil can be reduced.

A refrigeration cycle device according to a third aspect is the refrigeration cycle device according to the second aspect, and further includes a first temperature sensor. The first temperature sensor measures the discharge temperature of refrigerant discharged from the compressor. Also, the index is the discharge temperature.

A refrigeration cycle device according to the fourth aspect is the refrigeration cycle device according to the second aspect, wherein the index is the degree of superheat of the refrigerant discharged from the compressor.

The refrigeration cycle device of the fourth aspect can reduce the concentration of the liquid refrigerant dissolved in the oil of the compressor when there is a high possibility that a large amount of liquid refrigerant is dissolved in the oil of the compressor.

A refrigeration cycle apparatus according to a fifth aspect is the refrigeration cycle apparatus according to the fourth aspect, further including a first temperature sensor and a pressure sensor. The first temperature sensor measures the discharge temperature of refrigerant discharged from the compressor. A pressure sensor measures the pressure of the refrigerant in the radiator. The degree of superheat of the refrigerant discharged from the compressor is obtained from the discharge temperature and the pressure-equivalent saturation temperature of the refrigerant in the radiator.

The refrigeration cycle device of the fifth aspect measures the pressure of the refrigerant discharged from the compressor and the pressure-equivalent saturation temperature of the refrigerant in the radiator to obtain the degree of superheat of the refrigerant, and determines whether or not to perform the first heating control. Since it can be determined, it is possible to reduce the concentration of the liquid refrigerant dissolved in the oil of the compressor when there is a high possibility that a large amount of liquid refrigerant is dissolved in the oil of the compressor.

A refrigeration cycle apparatus according to a sixth aspect is the refrigeration cycle apparatus according to the fourth aspect, and has a first temperature sensor and a second temperature sensor. The first temperature sensor measures the discharge temperature of refrigerant discharged from the compressor. A second temperature sensor measures the coolant temperature in the radiator. The degree of superheat of the refrigerant discharged from the compressor is obtained from the discharge temperature and the refrigerant temperature in the radiator.

The refrigeration cycle device of the sixth aspect measures the pressure of the refrigerant discharged from the compressor and the temperature of the refrigerant in the radiator to obtain the degree of superheat of the refrigerant, and can determine whether or not to perform the first heating control. When there is a high possibility that a large amount of liquid refrigerant is dissolved in the oil of the compressor, the concentration of the liquid refrigerant dissolved in the oil of the compressor can be reduced.

The refrigeration cycle apparatus of the seventh aspect is the refrigeration cycle apparatus of the fifth aspect or the sixth aspect, wherein the controller controls the difference between the discharge temperature and the pressure equivalent saturation temperature, or the difference between the discharge temperature and the refrigerant temperature in the radiator. is equal to or less than a predetermined value, the first control is performed.

The refrigeration cycle device of the seventh aspect performs the first heating control when the degree of superheat is equal to or less than the predetermined value. It is possible to reduce the concentration of the dissolved liquid refrigerant.

A refrigeration cycle apparatus according to an eighth aspect is the refrigeration cycle apparatus according to any one of the first to seventh aspects, further comprising a heater. The heater heats the compressor. The controller performs first heating control to heat the compressor with the heater.

Since the refrigerating cycle device of the eighth aspect includes the heater that heats the compressor, it is possible to heat the compressor and reduce the concentration of the liquid refrigerant dissolved in the oil of the compressor.

A refrigeration cycle apparatus according to a ninth aspect is the refrigeration cycle apparatus according to any one of the first to seventh aspects, wherein the compressor has a compression section and a motor. The compression section compresses the refrigerant. A motor drives the compression section. The control unit performs first heating control of the compressor by energizing the motor.

Since the refrigeration cycle apparatus of the ninth aspect heats the compressor using the motor for driving the compression section, there is no need to use a heater for heating the compressor.

A refrigeration cycle apparatus according to a tenth aspect is the refrigeration cycle apparatus according to any one of the first to ninth aspects, and further includes a third temperature sensor. A third temperature sensor measures the ambient temperature. The control unit performs second heating control for heating the compressor based on the outside air temperature measured by the third temperature sensor while the compressor is stopped.

Since the refrigeration cycle device of the tenth aspect performs the second heating control while the compressor is out of operation, it is possible to more reliably suppress the large amount of liquid refrigerant from dissolving in the oil of the compressor due to fluctuations in the outside air temperature. can.

In the refrigeration cycle apparatus control method of the eleventh aspect, the refrigeration cycle apparatus has a compressor, a radiator, an evaporator, and a controller. The compressor compresses refrigerant. The radiator cools the coolant. The evaporator heats the refrigerant. The controller controls the compressor. The control method of the refrigeration cycle apparatus performs the following control. (a) The control unit stops the compressor, and (b) the control unit, following (a), performs first heating control for heating the stopped compressor.

In the refrigeration cycle device control method of the eleventh aspect, the first heating control is performed to heat the compressor continuously after stopping the compressor, so that it is possible to suppress a large amount of liquid refrigerant from dissolving in the oil of the compressor. can.

A control method for a refrigeration cycle apparatus according to a twelfth aspect is the control method according to the eleventh aspect, further comprising: (c) the control unit determining whether or not to perform the first heating control in (b); It is determined based on indicators relating to the discharge pipe temperature after or before shutdown, the degree of superheat of the refrigerant discharged from the compressor, and the degree of superheat or dryness of the refrigerant sucked into the compressor.

In the refrigeration cycle apparatus control method of the twelfth aspect, the first heating control is controlled based on the index after or before the compressor is stopped, so there is a possibility that a large amount of liquid refrigerant is dissolved in the oil of the compressor. When high, the compressor can be heated and the concentration of liquid refrigerant dissolved in the compressor oil can be reduced.

1 is an overall configuration diagram of a refrigeration cycle apparatus 1 of a first embodiment; FIG. It is a sectional view of compressor 11 of a 1st embodiment. 4 is a flowchart for explaining first heating control of the first embodiment; 4 is a timing chart for explaining first heating control of the first embodiment; FIG. 2 is a Mollier diagram of the refrigerant of the first embodiment; It is a whole block diagram of the refrigerating-cycle apparatus of 2nd Embodiment. It is a flow chart explaining the 1st heating control of a 3rd embodiment. It is a timing chart explaining the 1st heating control of a 3rd embodiment.

<First embodiment>
(1) Overall Configuration FIG. 1 shows an outline of the overall configuration of the refrigeration cycle apparatus 1 of the first embodiment. FIG. 1 mainly describes the refrigerant circuit. The refrigerating cycle device 1 of the present embodiment can be used for an air conditioner that performs cooling and heating, a water cooler/heater, and the like.

A refrigeration cycle apparatus 1 of this embodiment includes an outdoor unit 10 and an indoor unit 20 . The outdoor unit 10 includes a compressor 11 , a heater 41 , a four-way switching valve 15 , a heat source side heat exchanger 12 , an expansion valve 13 and a controller 21 . The indoor unit 20 includes a utilization side heat exchanger 14 . In the case of this form, in the user-side heat exchanger 14, the refrigerant exchanges heat with the indoor air. In the user-side heat exchanger, when performing heat exchange with another medium such as a refrigerant and water, the user-side heat exchanger may be arranged outdoors.

The refrigerant circuit of the refrigeration cycle apparatus 1 of this embodiment mainly includes a compressor 11, a four-way switching valve 15, a heat source side heat exchanger 12, an expansion valve 13, a utilization side heat exchanger 14, and a low pressure receiver. 16 and .

Compressor 11 compresses the refrigerant. The four-way switching valve 15 switches the refrigerant flow between the dashed line (heating) and the solid line (cooling) in FIG.

During heating operation, the refrigerant discharged from the compressor 11 passes through the user-side heat exchanger 14 , the expansion valve 13 , the heat source-side heat exchanger 12 , and the low-pressure receiver 16 and is sucked into the compressor 11 again. In other words, during heating, the utilization side heat exchanger 14 functions as a radiator, and the heat source side heat exchanger 12 functions as an evaporator.

During cooling operation, the refrigerant discharged from the compressor 11 passes through the heat source side heat exchanger 12, the expansion valve 13, the heat source side heat exchanger 12, the utilization side heat exchanger 14, and the low-pressure receiver 16, and then returns to the compressor 11. is inhaled into In other words, during cooling, the heat source side heat exchanger 12 functions as a radiator, and the utilization side heat exchanger 14 functions as an evaporator.

The radiator cools the refrigerant. The evaporator heats the refrigerant.

Also, the expansion valve 13 reduces the pressure of the refrigerant. The low-pressure receiver 16 temporarily stores the refrigerant before being sucked into the compressor so that liquid refrigerant is less likely to be sucked into the compressor.

In this embodiment, R32 (CH ₂ F ₂ ) is used as the refrigerant. R32 is known to have a relatively low ozone depletion potential of 0 and a critical temperature of 78.11°C.

(2) Detailed configuration (2-1) Compressor 11 and heater 41
FIG. 2 shows a longitudinal sectional view of the compressor 11 of this embodiment. The compressor of this embodiment is a two-cylinder rotary compressor. The compressor 11 may be of another type such as a scroll type.

The compressor 11 of this embodiment has a motor 52 , a compression section 51 and a crankshaft 53 inside a high-pressure container 54 . The motor 52 has a stator 52a and a rotor 52b. When the rotor 52b of the motor 52 rotates, the crankshaft 53 rotates and the refrigerant is compressed in the compression section. Refrigerant is sucked into the compression section 51 through the suction port 55 and compressed, moves upward as a whole along the arrow in FIG.

The bottom of the high-pressure vessel 54 is an oil reservoir 57 in which lubricating oil is stored. During operation of the compressor 11 , oil is pumped from the oil reservoir 57 to the compression portion 51 and used for lubrication of the compression portion 51 .

A crankcase heater 41 is wound around the outside of the high-pressure container 54 of the compressor 11 . When the outside air temperature is low, or when the compressor is in wet operation immediately before stopping and then when the compressor stops, the liquid refrigerant is likely to dissolve in the oil pool 57 . In such a case, the amount of the liquid refrigerant dissolved in the oil can be reduced by energizing the crankcase heater to heat the oil reservoir 57 .

(2-2) Temperature sensors 31, 32, 33, and 34 and control unit 21
A plurality of temperature sensors are arranged in the refrigeration cycle apparatus 1 of the present embodiment. The location of the sensors is shown in FIG.

The first temperature sensor 31 is attached at a position for measuring the discharge temperature of the refrigerant. The second temperature sensor 32 measures the temperature of the refrigerant in the user-side heat exchanger 14 (radiator during heating). The third temperature sensor 33 is an outside air temperature sensor. The fourth temperature sensor 34 measures the temperature of the refrigerant in the heat source side heat exchanger 12 (heat radiator during cooling).

The control unit 21 includes a processor and a storage unit (not shown). The controller 21 is arranged in the outdoor unit 10 . The controller controls the compressor 11 , the heater 41 and the temperature sensors 31 , 32 , 33 and 34 .

(3) Compressor heating control (3-1) First heating control during heating operation and when compressor is stopped Using the flowchart in FIG. 3 and the timing chart in FIG. 4, the compressor is stopped during heating operation. The first heating control of the compressor in the case of doing will be described.

In the refrigerating cycle device 1 of the present embodiment, the first temperature sensor 31 constantly measures the temperature of the refrigerant discharged from the compressor (discharge temperature) during operation of the refrigerating cycle device 1 . In the present embodiment, for example, the interval is one minute. This interval is typically greater than or equal to 1 second and less than or equal to 10 minutes. The discharge temperature measured by the first temperature sensor is sent to the controller 21 .

Similarly, the second temperature sensor 32 constantly measures the refrigerant temperature in the user-side heat exchanger 14 (radiator during heating) during operation of the refrigeration cycle apparatus 1 . In the present embodiment, the coolant temperature measured by the second temperature sensor 32 is the coolant saturation temperature. The measurement of the second temperature sensor is the same as the measurement of the first temperature sensor. The saturation temperature measured by the second temperature sensor 32 is sent to the controller 21 .

The controller 21 calculates the degree of superheat from the discharge temperature measured by the first temperature sensor 31 and the saturation temperature measured by the second temperature sensor. The degree of superheat is calculated as follows: Degree of superheat = Discharge temperature - Saturation temperature. The calculated degree of superheat is stored in the storage section of the control section 21 together with the measurement time.

Next, a case where the compressor stops (S101) during air conditioning operation will be described. The compressor stops when the user of the refrigeration cycle device (air conditioner) issues a command to stop the air-conditioning operation, or when the room reaches a predetermined temperature during the air-conditioning operation and the control unit stops the air-conditioning operation. and so on.

When the control unit 21 detects that the compressor has stopped operating in step S101, the process proceeds to step S102. In step S<b>102 , the control unit 21 reads data on the degree of superheat from the storage unit of the control unit 21 . In this embodiment, as the value of the degree of superheat in step S102, the average value of the degree of superheat 15 times (15 minutes) immediately before the stop of the compressor in FIG. use.

Next, the controller 21 determines whether or not the degree of superheat is equal to or less than a predetermined temperature (S103). The predetermined temperature is 10° C. here. The predetermined temperature may be 8° C. or higher and 12° C. or lower.

When the controller 21 determines that the degree of superheat exceeds 10° C., it ends this control.

When the controller 21 determines in step S103 that the degree of superheat is 10° C. or less, the process proceeds to step S104. In step S<b>104 , the crankcase heater 41 is turned on to heat the compressor 11 . The heater 41 starts heating within 30 minutes after the compressor 11 stops. Preferably, it is within 10 minutes. More preferably, it is within 1 minute. The time during which the heater 41 is on is, for example, 10 minutes or more and 60 minutes or less. Preferably, it is 10 minutes or more and 30 minutes or less. By heating the oil reservoir in the compressor with the heater 41, the refrigerant in the oil is evaporated and the concentration of the refrigerant can be lowered.

(3-2) Second heating control while compressor is stopped The second heating control is performed while the compressor is stopped.

In this embodiment, when the temperature is low, the third temperature sensor 33 measures the outside air temperature at predetermined time intervals even after the compressor stops. The predetermined time is, for example, 30 minutes. Here, when the measured outside air temperature is lower than the predetermined temperature, or when the outside air temperature tends to rise, the control unit energizes the heater to perform the second heating control to heat the compressor. This is because a large amount of refrigerant may be dissolved in the oil in the compressor 11 when the outside temperature is lower than a predetermined temperature or when the outside temperature tends to rise while the compressor is stopped. .

By performing the second heating control, the refrigerant concentration in the oil can be reduced.

(4) Features (4-1)
The refrigeration cycle apparatus of the present embodiment includes a compressor 11, a user-side heat exchanger 14 (radiator during heating), a heat source-side heat exchanger 12 (evaporator during heating), and a controller 21. I'm in. During the heating operation, the control unit performs first heating control for heating the stopped compressor 11 after stopping the compressor 11 .

The first heating control can reduce the concentration of the liquid refrigerant dissolved in the oil of the compressor 11 .

(4-2)
A case where the first heating control is effective is a case where the degree of superheat of the refrigerant sucked into the compressor 11 is insufficient. The case where the degree of superheat is insufficient is explained by the Mollier diagram of FIG. It is in the state of 1 or less. If the refrigerant sucked into the compressor stops after operating in such a state, a large amount of liquid refrigerant will dissolve in the oil in the compressor, which can easily lead to trouble when the compressor is restarted next time. . Specifically, when restarting, the refrigerant in the oil evaporates into bubbles and is discharged together with the discharged refrigerant, reducing the concentration of the oil and supplying enough oil to the sliding parts of the compressor. and the compressor compresses the liquid refrigerant and interferes with sliding. In such a case, the first heating control of this embodiment is effective.

In the refrigeration cycle apparatus, wet operation depends on various conditions. For example, it depends on the load during operation. When the load is small during operation of the refrigeration cycle apparatus, or when the compressor is operated at a low rotational speed for a long period of time, wet operation is likely to occur.

Next, as a condition for using the first heating control, based on the above, an index relating to the degree of superheat or the degree of dryness of the refrigerant sucked into the compressor before stopping the compressor may be used.

In this embodiment, instead of measuring the temperature of the refrigerant before being sucked into the compressor, the temperature of the refrigerant after being discharged from the compressor is measured to perform the first heating control.

Specifically, the degree of superheat of the refrigerant discharged from the compressor is used. This corresponds to the line segment BC on the Mollier diagram of FIG. In this embodiment, the refrigeration cycle apparatus 1 has temperature sensors 31 and 32 . The first temperature sensor 31 measures the discharge temperature of refrigerant from the compressor (the temperature at point B). A second temperature sensor 32 measures the temperature of the coolant in the radiator (the temperature above DC). On line segment DC, the refrigerant is saturated and the temperature is a constant saturation temperature. Then, the degree of superheat is obtained from discharge temperature−saturation temperature=degree of superheat. When the degree of superheat is equal to or lower than the predetermined temperature, it is assumed that the degree of superheat of the refrigerant before being sucked into the compressor is insufficient, and the first heating control is performed.

(4-3)
In this embodiment, the temperature of the refrigerant after being discharged from the compressor is measured instead of measuring the temperature of the refrigerant before being sucked into the compressor. Although the refrigerant temperature may be measured before compressor suction, measuring the refrigerant temperature after compressor discharge has the following advantages.

Although it depends on various conditions such as the refrigerant and the characteristics of the compressor, in this embodiment, the degree of superheat (equivalent to GA) before refrigerant suction is higher than the degree of superheat (equivalent to BC) after refrigerant discharge. small. Further, as shown by the dotted line _A1B1 in FIG. 5, when the refrigerant before being sucked into _the compressor has a dryness of less than 1, even if the temperature is measured at point _A1 , the temperature at point _A1 is saturated. No difference in temperature. Therefore, in this embodiment, the temperature of the refrigerant is measured after it is discharged from the compressor and used for control.

(4-4)
In this embodiment, the degree of superheat is determined by temperature measurement only, without pressure measurement.

Since the refrigeration cycle apparatus 1 of this embodiment does not need to be equipped with a pressure gauge, the configuration can be simplified.

(5) Modification (5-1) Modification 1A
In the first embodiment, the degree of superheat is calculated using the first and second temperature sensors 31 and 32 . In variant 1A, only the first temperature sensor is used to calculate the degree of superheat.

In modification 1A, the first temperature sensor 31 measures the discharge temperature of the refrigerant discharged from the compressor. In Modified Example 1A, the saturation temperature on the line segment DC is estimated based on the rotation speed of the compressor before shutdown. Discharge temperature−saturation temperature=degree of superheat is calculated, and it is determined whether or not the degree of superheat exceeds a predetermined temperature, and the first heating control of the compressor is performed. Other configurations and controls are the same as in the first embodiment.

In Modification 1A, there is one temperature sensor, the first heating control is possible, and the device configuration and control can be made simpler.

(5-2) Modification 1B
The compressor 11 of the first embodiment had the crankcase heater 41 . In the first and second heating controls, if the compressor 11, especially the oil reservoir 57 can be heated when the compressor is stopped, the crankcase heater may not be used. In Modification 1B, the compressor motor 52 is utilized. In other words, the motor is energized while the rotor 52b of the motor is not rotating. This energization may be an open-phase energization. By energizing the motor, the motor is caused to generate heat, and the compressor 11 is heated.

Other configurations of Modification 1B are similar to those of the first embodiment. Since the refrigeration cycle apparatus of Modification 1B does not use a special heater, the first heating control can be executed while having a simpler configuration.

(5-3) Modification 1C
In the first embodiment, during the operation of the refrigeration cycle apparatus, the first temperature sensor 31 constantly measures the discharge temperature and the second temperature sensor 32 measures the saturation temperature. It was calculated and stored in the storage section of the control section 21 . Then, in step S102, data on the degree of superheat is read, and in step S103, it is determined whether or not the first heating control is to be performed.

In the modification 1C, the measured discharge temperature and saturation temperature are stored in the storage section of the control section 21 during operation of the refrigeration cycle apparatus. After stopping the compressor, in step S102, the discharge temperature and the saturation temperature are called from the storage unit of the control unit 21 instead of the degree of superheat. Then, in step S103, the controller 21 calculates the degree of superheat using the formula of degree of superheat=discharge temperature−saturation temperature. As in the first embodiment, the degree of superheat is calculated 15 times (15 minutes) before the compressor is stopped, and the average value thereof is used as the degree of superheat data. Whether or not to perform the first heating control is determined depending on whether or not the degree of superheat exceeds a predetermined temperature (here, 10° C.). Other configurations of Modification 1C are similar to those of the first embodiment.

The refrigerating cycle device of Modification 1C also has the configurations and effects of (4-1) to (4-4), like the refrigerating cycle device of the first embodiment.

(5-4) Modification 1D
In the first embodiment, in step S103, the degree of superheat used to determine whether or not to perform the first heating control was the average value of the degree of superheat obtained from 15 measurements immediately before stopping the compressor. . In Modified Example 1D, determination is made based on whether or not all 15 values of the degree of superheat are equal to or less than a predetermined value.

The refrigerating cycle device of Modification 1D also has the configurations and effects of (4-1) to (4-4), like the refrigerating cycle device of the first embodiment.

(5-5) Modification 1E
In the first embodiment, in step S103, the average degree of superheat of the previous 15 times is used to determine whether or not to perform the first heating control. In Modified Example 1E, the control unit 21 estimates the degree of superheat when the compressor is stopped from the time change of the degree of superheat for 15 minutes. Next, in step S103, the control unit 21 determines whether or not to perform the first heating control based on whether or not the estimated degree of superheat is equal to or less than a predetermined value.

The refrigeration cycle apparatus of Modification 1E can evaluate the degree of superheat more accurately, and can more appropriately determine whether or not to perform the first heating control.

(5-6) Modification 1F
1st Embodiment was the case where the refrigerating-cycle apparatus (air conditioner) performs heating operation (in the case of a water cooler/heater, hot water production operation). Modification 1F is a case of performing a cooling operation (in the case of a water cooler/heater, cold water generation operation). The first heating control is effective even when the operating state of the compressor is wet operation during cooling operation.

The refrigeration cycle apparatus of Modification 1E further has a fourth temperature sensor 34 that measures the refrigerant temperature of the heat source side heat exchanger 12 .

In the case of cooling operation, the heat source side heat exchanger 12 functions as a radiator, and the utilization side heat exchanger 14 functions as an evaporator. Therefore, in the control flow for determining whether or not to perform the first heating control using FIG. A temperature sensor 34 is used. Other configurations and processes are the same as in the first embodiment.

The first heating control during the cooling operation may be performed only during the cooling operation, or may be performed both during the heating operation and during the cooling operation in combination with the first embodiment.

Since the refrigeration cycle apparatus of Modification 1F performs the first heating control even during cooling, it is possible to suppress troubles during restart after the compressor stops due to wet operation.

<Second embodiment>
(6) Configuration of Refrigeration Cycle Device of Second Embodiment and First Heating Control of Compressor FIG. 6 shows a schematic configuration of a refrigeration cycle device of the second embodiment. In the first embodiment, the second temperature sensor 32 that measures the temperature of the refrigerant in the radiator is used to obtain the saturation temperature of the discharged refrigerant. In the second embodiment, a pressure sensor 35 is used to measure the pressure of the refrigerant in the radiator (the user-side heat exchanger 14 during heating) to determine the saturation temperature of the discharged refrigerant. When the refrigerant type is specified, the saturation temperature can be uniquely determined by obtaining the pressure of the refrigerant in the radiator. This saturation temperature is also called pressure-equivalent saturation temperature. Other configurations and controls are the same as in the first embodiment.

In the refrigerating cycle device 1 of the present embodiment, the first temperature sensor 31 detects the temperature of the refrigerant discharged from the compressor (discharge temperature ) is measured. In addition, the control unit 21 uses the pressure sensor 35 to measure the pressure of the refrigerant in the radiator (the user-side heat exchanger 14 during heating).

In the refrigerating cycle device of the second embodiment, the storage unit of the control unit 21 stores the relationship between the pressure of the refrigerant used in the refrigerating cycle device and the saturation temperature. When the pressure sensor 35 measures the pressure of the refrigerant in the radiator (use side heat exchanger 14 during heating), pressure measurement data is sent to the control unit 21 . Based on the pressure measurement data, the control unit 21 obtains the saturation temperature from the relationship between the pressure of the refrigerant and the saturation temperature. On the other hand, the first temperature sensor 31 measures the temperature of the refrigerant discharged from the compressor 11 (discharge temperature), and the measurement data of the discharge temperature is sent to the controller 21 . The controller 21 calculates the degree of superheat from the saturation temperature obtained from the pressure measurement and the discharge temperature. The calculation formula is superheat degree=discharge temperature-saturation temperature.

In the present embodiment, as in the first embodiment, when the compressor 11 stops, the control unit 21 acquires the data of 15 times (15 minutes) immediately before the stop of the compressor 11 to calculate the degree of superheat. (or read out), and the average value is used as the value of the degree of superheat to determine whether or not to perform the first heating control.

As in the first embodiment, the refrigeration cycle apparatus of the second embodiment can reduce the concentration of the liquid refrigerant dissolved in the oil of the compressor when a large amount of liquid refrigerant is dissolved in the oil of the compressor.

(7) Modification (7-1) Modification 2A
In the second embodiment, the average value of the degree of superheat obtained from 15 measurements immediately before stopping the compressor is used to determine whether or not to perform the first heating control. In Modification 2A, similar to Modification 1D, determination is made based on whether or not all superheat values obtained from 15 measurements are equal to or less than a predetermined value.

The refrigerating cycle apparatus of Modification 2A also has the configurations and effects of (4-1) to (4-3) like the refrigerating cycle apparatuses of the first and second embodiments.

(7-2) Modification 2B
In the first embodiment, the average value of the degree of superheat obtained from 15 measurements immediately before stopping the compressor is used to determine whether or not to perform the first heating control. In modification 2B, as in modification 1E, the degree of superheat at the time of compressor stop is estimated from the time change in the degree of superheat for 15 minutes immediately before the stop of the compressor, and the estimated value is equal to or less than a predetermined value. is used to determine whether or not to perform the first heating control.

Similar to Modification 1E, the refrigeration cycle apparatus of Modification 2B can more accurately evaluate the degree of superheat and more appropriately determine whether or not to perform the first heating control.

(7-3) Modification 2C
2nd Embodiment was the case where the refrigerating-cycle apparatus (air conditioner) performs heating operation (in the case of a chiller/heater, hot water production operation). Modification 2C is a case of performing cooling operation (cold water generation operation in the case of a water cooler/heater). The first heating control is effective even when the operating state of the compressor is wet operation during cooling operation.

The refrigeration cycle apparatus of Modification 2C further has a pressure sensor (not shown) that measures the refrigerant pressure of the heat source side heat exchanger 12 (radiator during cooling).

In the case of cooling operation, the heat source side heat exchanger 12 functions as a radiator, and the utilization side heat exchanger 14 functions as an evaporator. Therefore, in the second embodiment, a pressure sensor for measuring the refrigerant pressure of the radiator (heat source side heat exchanger 12) is used as the pressure sensor for obtaining the saturation temperature. Other configurations and processes are the same as those of the second embodiment.

The first heating control during the cooling operation may be performed only during the cooling operation, or may be performed both during the heating operation and during the cooling operation in combination with the second embodiment.

Since the refrigeration cycle apparatus of Modification 1F performs the first heating control even during cooling, it is possible to suppress troubles during restart after the compressor stops due to wet operation.

<Third Embodiment>
(8) Configuration of Refrigerating Cycle Device of Third Embodiment and First Heating Control of Compressor In the refrigerating cycle device of the first embodiment, the first temperature sensor 31 and the second temperature sensor 32 of the refrigerating cycle device The temperature was measured periodically during operation. In the refrigeration cycle apparatus of the third embodiment, the refrigerant temperature used for the first heating control is measured after the compressor 11 is stopped.

In this embodiment, the first heating control of the compressor 11 during the heating operation will be described with reference to the flowchart of FIG. 7 and the timing chart of FIG.

In step S301, the control unit 21 detects that the compressor 11 is stopped. Next, in step S<b>302 , the first temperature sensor 31 measures the temperature of the discharge pipe of the compressor 11 . Let the measured value of this 1st temperature sensor 31 be discharge temperature. Almost simultaneously, the second temperature sensor 32 measures the refrigerant temperature in the user-side heat exchanger 14 (radiator during heating). The coolant temperature measured by the second temperature sensor 32 is the saturation temperature of the coolant.

Next, the controller 21 calculates the degree of superheat from the data of the discharge temperature measured by the first temperature sensor 31 and the saturation temperature measured by the second temperature sensor 32 . The degree of superheat is calculated as follows: Degree of superheat = Discharge temperature - Saturation temperature. Then, the control unit 21 determines whether or not the degree of superheat is equal to or lower than a predetermined temperature (S303). The predetermined temperature is 10° C. here. The predetermined temperature may be 8° C. or higher and 12° C. or lower.

When the controller 21 determines that the degree of superheat exceeds 10° C., it ends this control.

When the controller 21 determines in step S303 that the degree of superheat is 10° C. or less, the process proceeds to step S304. The crankcase heater 41 is turned on in step S304 to heat the compressor 11 . The heater 41 starts heating within 30 minutes after the compressor 11 stops. Preferably, it is within 10 minutes. More preferably, it is within 1 minute. The time during which the heater 41 is on is, for example, 10 minutes or more and 60 minutes or less. Preferably, it is 10 minutes or more and 30 minutes or less. By heating the oil reservoir in the compressor with the heater 41, the refrigerant in the oil is evaporated and the concentration of the refrigerant can be lowered.

The refrigeration cycle apparatus of the third embodiment has features (4-1) to (4-4) like the refrigeration cycle apparatus of the first embodiment.

(9) Modification (9-1) Modification 3A
In the third embodiment, the first and second temperature sensors 31 and 32 are used to calculate the degree of superheat. In the modification 3A, the pressure equivalent saturation temperature of the refrigerant in the radiator is obtained by using the pressure sensor 35 instead of the second temperature sensor 32, as in the second embodiment. Other configurations are the same as those of the third embodiment.

The refrigerating cycle device of Modification 3A has features (4-1) to (4-3) like the refrigerating cycle device of the first embodiment.

(9-2) Modification 3B
The third embodiment is a case where a refrigeration cycle device (air conditioner) performs a heating operation (in the case of a water cooler/heater, a hot water generation operation). Modification 3B, like modification 1F, is a case in which the cooling operation (cold water generation operation in the case of a chiller/heater) is performed. During cooling operation, the first heating control is effective when the operating state of the compressor is wet operation.

The refrigeration cycle apparatus of Modification 3B further has a fourth temperature sensor 34 that measures the refrigerant temperature of the heat source side heat exchanger 12, as in Modification 1F.

The first heating control of Modification 3A may be performed only during the cooling operation, or may be performed both during the heating operation and during the cooling operation in combination with the third embodiment.

Since the refrigeration cycle apparatus of Modification 1F performs the first heating control even during cooling, it is possible to suppress troubles during restart after the compressor stops due to wet operation.

Although embodiments of the present disclosure have been described above, it will be appreciated that various changes in form and detail may be made without departing from the spirit and scope of the present disclosure as set forth in the appended claims. .

Refrigeration cycle device 1
Compressor 11
heat source side heat exchanger 12
User-side heat exchanger 14
control unit 21
First temperature sensor 31
Second temperature sensor 32
Third temperature sensor 33
Fourth temperature sensor 34
pressure sensor 35
Crankcase heater 41
Compressor 51
motor 52

JP 2010-65958 A

Claims (12)

a compressor (11) for compressing a refrigerant;
a radiator (14) for cooling the refrigerant;
an evaporator (12) for heating the refrigerant;
a control unit (21) for controlling the compressor;
A refrigeration cycle device (1) comprising
The control unit performs first heating control to heat the stopped compressor continuously after stopping the compressor,
The control unit determines whether to perform the first heating control based on an index related to the degree of superheat or dryness of the refrigerant sucked into the compressor before stopping the compressor.
Refrigeration cycle equipment. The control unit determines whether or not to perform the first heating control based on an index relating to the degree of superheat or dryness of the refrigerant sucked into the compressor after and before the compressor is stopped. ,
The refrigeration cycle apparatus according to claim 1. The refrigeration cycle device further includes
a first temperature sensor (31) for measuring the discharge temperature of the refrigerant discharged from the compressor;
with
wherein the index is the discharge temperature;
The refrigeration cycle device according to claim 1 or 2 . the indicator is the degree of superheat of the refrigerant discharged from the compressor,
The refrigeration cycle device according to claim 1 or 2 . The refrigeration cycle device is
a first temperature sensor that measures the discharge temperature of the refrigerant discharged from the compressor;
further comprising a pressure sensor (35) for measuring the pressure of the refrigerant in the radiator;
The degree of superheat of the refrigerant discharged from the compressor is obtained from the discharge temperature and the pressure equivalent saturation temperature of the refrigerant in the radiator,
The refrigeration cycle apparatus according to claim 4. The refrigeration cycle device is
a first temperature sensor (31) for measuring the discharge temperature of the refrigerant discharged from the compressor;
further comprising a second temperature sensor (32) for measuring refrigerant temperature in the radiator;
The degree of superheat of the refrigerant discharged from the compressor is obtained from the discharge temperature and the refrigerant temperature in the radiator,
The refrigeration cycle apparatus according to claim 4. The control unit performs the first heating control when a difference between the discharge temperature and the pressure equivalent saturation temperature or a difference between the discharge temperature and the refrigerant temperature in the radiator is equal to or less than a predetermined value.
The refrigeration cycle apparatus according to claim 5 or 6. The refrigeration cycle device is
a heater (41) for heating the compressor,
further prepared,
The control unit performs the first heating control to heat the compressor with the heater,
The refrigeration cycle apparatus according to any one of claims 1 to 7. The compressor (11) is
a compression section (51) for compressing the refrigerant;
a motor (52) for driving the compression section;
has
The control unit performs the first heating control of the compressor by energizing the motor.
The refrigeration cycle apparatus according to any one of claims 1 to 7. The refrigeration cycle device is
A third temperature sensor (33) that measures the outside air temperature,
further prepared,
The control unit performs second heating control for heating the compressor based on the outside air temperature measured by the third temperature sensor while the operation of the compressor is stopped.
The refrigeration cycle apparatus according to any one of claims 1 to 9. a compressor (11) for compressing a refrigerant;
a radiator (14) for cooling the refrigerant;
an evaporator (12) for heating the refrigerant;
a control unit (21) for controlling the compressor;
A control method for a refrigeration cycle device (1) comprising
(a) the control unit stops the compressor;
(b) The control unit, subsequent to (a), determines whether or not to perform first heating control for heating the stopped compressor, the discharge pipe temperature before stopping the compressor, the compressor The degree of superheat of the refrigerant discharged from the compressor, or the degree of superheat or dryness of the refrigerant sucked into the compressor. When it is decided to perform the first heating control, the first heating control I do,
A control method for a refrigeration cycle device. The method for controlling the refrigeration cycle device further comprises:
(c) The control unit determines whether or not to perform the first heating control in (b) by determining the discharge pipe temperature after and before the compressor is stopped and the degree of superheat of the refrigerant discharged from the compressor. , or determined based on an index related to the degree of superheat or dryness of the refrigerant sucked into the compressor,
A control method for a refrigeration cycle apparatus according to claim 11 .

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