JP2001073952A - Heating device for compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heating device for a compressor economically profitable and capable of satisfactorily preventing flooded phenomenon of a refrigerant in the compressor. SOLUTION: A compressor for an air conditioner comprising a refrigerant circuit is provided with a compressor heater 140 capable of heating thereof, and operation of the compressor heater 140 is controlled by a CPU 100. Heater control is performed by obtaining a saturation temperature of a refrigerant in the compressor from a pressure of the refrigerant detected by a high pressure side pressure sensor 81 provided in the refrigerant circuit, followed by comparison between the saturation temperature and detected temperature detected by compressor temperature sensors 24, 25 provided in the compressor to determine whether the refrigerant in the compressor is under an easily condensable condition. The compressor heater 140 is operated only when the refrigerant is under the easily condensable condition during stopping of the compressor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compressor heating device applied to a refrigerant circulation type heat transfer device such as an air conditioner.

[0002]

2. Description of the Related Art Conventionally, as a refrigerant circulation type heat transfer device as described above, for example, a condenser and an evaporator are used indoors.
It has an outdoor heat exchanger, performs heating and cooling by circulating the refrigerant through a refrigerant circuit including a compressor and indoor and outdoor heat exchangers, and switches the circulation direction of the refrigerant to the indoor and outdoor heat exchangers. An air conditioner (air conditioner) is generally known in which a valve is provided in the refrigerant circuit so that heating and cooling can be switched by operating the four-way valve.

[0003]

In the above-described air conditioner, the compressor is stopped when the device is stopped or when the device is operating and the room temperature reaches the target temperature. In a state where the compressor is stopped, the refrigerant temperature is reduced and condensed therein (so-called stagnation phenomenon). For example, the refrigerant is mixed into the lubricating oil accumulated in the oil sump and induces poor lubrication when restarting. It causes troubles. Therefore, generally, a heater is attached to the compressor and the stopped compressor is heated by the heater to suppress the condensation of the refrigerant.

[0004] However, in the conventional apparatus, the heater is always operated while the compressor is stopped to heat the compressor, so that power consumption is large and uneconomical.

[0005] In view of such circumstances, an object of the present invention is to provide a compressor heating device which can favorably prevent the refrigerant from stagnation in the compressor and is economically advantageous.

[0006]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is applied to a refrigerant circulation type heat transfer device configured to circulate refrigerant discharged from a compressor to a predetermined refrigerant circuit. A heating device for the compressor, a heater for heating the compressor, pressure detection means for detecting a refrigerant pressure in the compressor or a pressure related to the pressure, and a refrigerant temperature in the compressor or a temperature related to the temperature. A temperature detecting means for detecting, a saturation temperature calculating means for obtaining a saturation temperature of the refrigerant in the compressor based on a pressure detected by the pressure detecting means, and a refrigerant which compares the obtained saturated temperature with the temperature detected by the temperature detecting means to determine whether the refrigerant is Control means for judging a state in which the compressor is easily condensed, and controlling a heater to heat the compressor when the compressor is stopped and the refrigerant in the compressor is in a state in which the refrigerant is easily condensed. (Claim 1).

According to this device, a state in which the refrigerant in the compressor is easily condensed is determined, and the heater is operated to heat the compressor only when the refrigerant is easily condensed. Therefore, the operation of the heater can be minimized.

In this device, the temperature detecting means is configured to detect the temperature of the compressor as a temperature related to the refrigerant temperature in the compressor, and a safety value in consideration of the heat capacity of the compressor is added to the saturation temperature. The control means may be configured to compare the detected value with the detected temperature of the compressor to determine a state in which the refrigerant is easily condensed (claim 2).

According to this configuration, it is possible to perform the above-described heater control without installing the temperature detecting means inside the high-temperature and high-pressure compressor.

In the case of circulating a mixed refrigerant obtained by mixing a plurality of kinds of refrigerants, a composition ratio detecting means capable of detecting a composition ratio of the mixed refrigerant is provided, and a pressure detected by the pressure detecting means and a composition ratio detecting means are provided. The above-mentioned saturation temperature calculation means is configured to obtain the saturation temperature for each type of refrigerant based on the detected composition ratio, and the state in which the refrigerant easily condenses based on the highest saturation temperature among the saturation temperatures of each type of refrigerant. The control means is configured to make a determination (claim 3).

According to this configuration, a state in which the refrigerant easily condenses is determined based on the refrigerant having the highest saturation temperature among the refrigerants constituting the mixed refrigerant.

[0012]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows an air conditioner as an example of a refrigerant circulation type heat transfer device according to the present invention.
It is composed of an outdoor unit 1a and a plurality of indoor units 1b. This air conditioner includes a water-cooled gas engine 2
(Hereinafter, abbreviated as engine 2), a refrigerant circuit 30 including a compressor 20 driven by the engine 2, and a cooling water circuit 90 for cooling the engine 2 are provided. 30 is disposed over the outdoor unit 1a and each indoor unit 1b, and the compressor 20, the engine 2, the cooling water circuit 90, etc. in the refrigerant circuit 30 are disposed in the outdoor unit 1a.

An intake pipe 3 is connected to the engine 2.
The intake pipe 3 is provided with an air cleaner 4, a mixer 5, a throttle valve 6, and the like. In the mixer 5,
A fuel supply pipe 7 for guiding fuel from a fuel gas supply source (not shown) is connected, and a flow control valve 8, electromagnetic valves 9, 10 and the like are interposed in the fuel supply pipe 7. The fuel gas and the air are mixed by the mixer 5, and the amount of the air-fuel mixture is controlled by the throttle valve 6, whereby the output of the engine 2 is controlled.

An exhaust pipe 11 is led out of the engine 2, and an exhaust gas heat exchanger 12 is interposed in the exhaust pipe 11. Further, an oil tank 14 is connected to an oil pan of the engine 2 via an oil supply pipe 13.
The oil supply pipe 13 is provided with a solenoid valve 15 for adjusting the oil supply amount. Reference numeral 16 denotes a heater for adjusting the oil temperature in the oil pan of the engine 2. Reference numeral 17 denotes an exhaust gas temperature sensor for detecting the exhaust gas temperature.

The refrigerant circuit 30 passes the refrigerant discharged from the compressor 20 through a condenser, a throttle, and an evaporator.
To form a closed circuit for circulating so as to return to. In the present embodiment, a four-way valve 31 for switching the refrigerant circulation path according to the time of cooling and the time of heating is provided, and the outdoor heat exchanger 32 that forms one of the condenser and the evaporator, and the other that forms the other An indoor heat exchanger 33 and an electronic expansion valve 34 constituting a throttle. The four-way valve 31 and the outdoor heat exchanger 32 are provided in the outdoor unit side circuit of the refrigerant circuit 30, while the indoor heat exchanger 33 and the electronic expansion valve 34 are provided in a plurality of indoor unit side circuits, respectively. Have been.

More specifically, the refrigerant circuit 30 will be described. Between the compressor 20 and the four-way valve 31, a discharge-side line 41 connecting the discharge port of the compressor 20 and the first port 31a of the four-way valve 31 is provided. , The second port 31b of the four-way valve 31 and the compressor 20
And a suction-side line 42 for connecting the suction port with the suction port. The discharge side line 41 is provided with an oil separator 43 for separating oil from the high-pressure refrigerant, and the separated oil is guided to a downstream portion of the suction side line 42 via a strainer 44 and a capillary tube 45. I have.

An accumulator 46 is provided on the suction side line 42. The suction-side line 42 includes an upstream line 42a connecting the four-way valve 31 and the inlet of the accumulator 46, a line 42b connected to the outlet of the gas-phase refrigerant of the accumulator 46, and a capillary 47 connected to the line 42b. A downstream line 42c connected via a U-shaped line 42d, the downstream line 42c being connected to a suction port of the compressor 20, and oil in the compressor 20 being supplied to a line 42d and a downstream line. 42
An oil circulation passage 42e for returning to the compressor 20 again through the line c is connected to the line 42d from the compressor 20 via a strainer 50, a valve 49 and a capillary tube 48.

The gas-phase refrigerant and the liquid-phase refrigerant are separated by the accumulator 46, and the gas-phase refrigerant is supplied to the line 42b,
The air is sucked into the compressor 20 via the capillary tube 47 and the line 42c. Also, in order to derive the liquid-phase refrigerant in the accumulator 46 when the operation is stopped as necessary,
The lower end of the accumulator 46 is connected to the line 42d via a passage having the strainer 51 and the control valve 52.

A predetermined high level position and a predetermined low level position (for example, the lowest position) of the accumulator 46 are connected to a line 42d through passages 53 and 54 for detecting liquid level.
Strainers 55, 56 are provided in the respective passages 53, 54, respectively.
And capillaries 57, 58 are provided, and each passage 5
Heaters 59, 60 and temperature sensor 6 for 3, 54
1, 62 are provided. The liquid level in the accumulator, that is, the storage amount of the liquid-phase refrigerant, is detected by detecting a temperature change in the passage when the liquid-phase refrigerant is led out to the paths 53 and 54.

The accumulator 46 is provided with a heater 63. The four-way valve 31 and the accumulator 46
A heat exchanger 64 for heating the refrigerant with engine waste heat is provided in the line 42a between the heat exchanger 64 and the heat exchanger 64.

An outdoor heat exchanger 32 is connected to a third port 31c of the four-way valve 31 via a line 65, and a line 66 is connected to the outdoor heat exchanger 32. This line 66 passes through the heat exchanger 38 and reaches the joint 69 via the strainer 67 and the manual valve 68. The line 70 is connected to the fourth port 31d of the four-way valve 31,
This line 70 reaches a joint 73 via a strainer 71 and a manual valve 72.

On the other hand, each indoor unit 1b is provided with an indoor heat exchanger 33 and an electronic expansion valve 34 connected in series.
The indoor heat exchanger 33 is connected to a line 74 connected to the external unit 0 via a joint 73, and the electronic expansion valve 34 is connected to a line 75 connected to a line 66 of the outdoor unit side circuit via a joint 69. ing.

Further, an electronic expansion valve 34 is provided in the refrigerant circuit 30.
In this embodiment, a bypass passage 36 that connects the high-pressure refrigerant circuit and the low-pressure refrigerant circuit is provided in parallel to the middle of a line 70 that communicates with the fourth port 31d of the four-way valve 31 in the outdoor unit-side circuit. The bypass passage 36 is connected to the middle of a line 66 connected to the
Is formed in the middle of the bypass passage 36.
7. A strainer 76 is provided and a refrigerant temperature sensor 77 is provided. Also, the refrigerant temperature sensors 7 are provided on the upstream and downstream sides of the heat exchanger 38 in the line 66.
8,79 are provided.

In addition to the above, various detection elements provided for the refrigerant circuit 30 include a high pressure side pressure sensor (pressure detection means) 81, a low pressure side pressure sensor 82, a compressor discharge side refrigerant temperature sensor 83, and a compressor suction side. A refrigerant temperature sensor 84, an outside air temperature sensor 85, etc. are provided on the outdoor unit 1a side, and refrigerant temperature sensors 86, 87, an indoor temperature sensor 88, etc. on the upstream and downstream sides of the electronic expansion valve 34 are connected to the indoor unit 1b side. It is arranged in.

On the other hand, the cooling water circuit 90 includes a main water pump 92, an exhaust gas heat exchanger 12, an engine-side water pump 93, an engine water jacket, a thermostat 94, a linear three-way valve 95, a radiator 96, and the like. A cooling water passage 91 is provided, and a passage 97 for guiding engine waste heat to the heat exchanger 63 is provided.
This passage 97 branches off the main cooling water passage 91 via a linear three-way valve 95 on the way of the cooling water circulating in the main cooling water passage 91 from the engine water jacket to the radiator 96, and branches the heat exchanger 64. After passing through, it is formed to join the main cooling water passage 91.

The linear three-way valve 95 is connected to the main cooling water passage 9.
The rate at which the cooling water is diverted from 1 to the passage 97 can be linearly changed. The cooling water that has received the engine waste heat is guided to the linear three-way valve 95, and is moved to the operating position of the linear three-way valve 95. The heat exchanger 64 is guided to the heat exchanger 64 via the passage 97 by a corresponding amount.
Thus, the engine waste heat is supplied to the low-pressure refrigerant in the suction side line 42 of the refrigerant circuit 30.

The specific structure of the compressor 20 applied to the refrigerant circuit 30 is not particularly limited in the present invention.
And a multi-type compressor having a plurality of compressor bodies 122, each of which has an electromagnetic clutch 21a, 2c.
1b, it is connected to the output shaft 22 of the engine 2.

The compressor 20 will be described more specifically. As shown in FIG. 2 and FIG. 3, the compressor 20 has a case 121 in which left and right (left and right in FIG. 3; The compressor main body 122 includes two compressor main bodies 122 and an oil reservoir 123 provided as a lubricant supply source in common with each of the compressor main bodies 122.

In the compressor 20, as shown by the dashed arrow in FIG.
The refrigerant is sucked and compressed into a high-temperature, high-pressure gaseous refrigerant from an oil reservoir 1 via an oil separator 124.
23, and from the discharge side line 41 connected to the ceiling of the oil reservoir 123, the refrigerant circuit 3
0 is supplied.

As shown by a solid line arrow in the figure, an oil supply port 127 opened in the oil reservoir 123 which becomes high pressure.
, And circulates the lubricating oil through the sliding portion of each compressor body 122. The lubricating oil is mixed with the gaseous refrigerant in each compressor main body 122, and is separated when being discharged together with the gaseous refrigerant into the oil reservoir 123 through the oil separator 124 and returned to the oil reservoir 123. ing.

A drain plug 12 is provided at the lower part of the case 121.
1A is attached, and is detached when the oil in the oil reservoir 123 is changed. A pipe constituting a part of the oil circulation passage 42 e is provided at a lower portion of the case 121 so as to project into the oil reservoir 123. During the operation of the compressor 20, the valve 49 is opened and the oil in the oil reservoir 123 is sucked into the compressor 20 again through the line 42c, and this oil is added to the lubrication using the oil supply port 127. Rotor 132 in the form
Used for lubrication of etc. When the compressor 20 is stopped, a large amount of oil is supplied from the oil sump 123 to the line 4.
Valve 49 is closed to prevent it from flowing out to 2d.

The compressor body 122 includes the electromagnetic clutch 2
It comprises a drive shaft 131 connected to the output shaft 22 via 1a, 21b, a rotor 132 rotating integrally with the drive shaft 131, and a cylinder 134 having an elliptical inner wall.

The rotor 132 is provided with a plurality of vanes 133 which are urged in the radial direction and whose leading ends are in sliding contact with the inner wall of the cylinder 134, whereby two compression spaces which are variable with the rotation of the rotor 132 are formed. It is formed in the cylinder 134. The cylinder 134 has a communication passage 135 corresponding to each compression space and a plate valve 1.
And a discharge port 136 provided with an outlet 37. Then, in each compressor body 122, the rotation of the rotor 132 causes the refrigerant refluxed from the refrigerant circuit 30 to flow into the intake port on one side of the rotor 132 and to each communication passage 135.
The air is sucked from the intake port on the other side through the outlet, compressed in each of the above-described compression spaces, and then discharged from each of the discharge ports 136 to the discharge path 1.
The oil is led to the oil separator 124 via 39.

Further, a compressor heater 140 for heating the compressor 20 corresponding to the oil reservoir 123 is attached to the casing 121 of the compressor 20, and a temperature of the compressor 20 is detected. Compressor temperature sensors 24 and 25 are attached to the casing 121 so as to correspond to the respective compressor main bodies 122. Then, the temperature of the compressor 20 is detected from time to time by the compressor temperature sensors 24 and 25 and output to the CPU 100 (shown in FIG. 4) described later. 140 is controlled.

FIG. 4 shows a control system of the air conditioner. The control system shown in this figure has a system CPU 100 that controls the entire system and functions as a control unit and a saturation temperature calculation unit of the present invention, and an engine CPU 106 that controls the engine 2.
Are electrically connected so that control can be performed in relation to each other. Further, the system CPU 100 includes:
The operation unit 101 (if a remote control is provided, includes the remote control and its transmission / reception unit) provided in the indoor unit 1a, the refrigerant temperature sensors 86 and 87, and the indoor temperature sensor 8
8, the electronic expansion valve 34 and the indoor fan 102 are connected, and the high pressure side pressure sensor 81, the low pressure side pressure sensor 82, the outside air temperature sensor 85, the accumulator liquid level sensors 61 and 62, the compressor temperature provided in the outdoor unit are provided. Sensors 24, 25, refrigerant temperature sensors 77, 78, 79, 84,
Defrost switch 103, four-way valve 31, linear three-way valve 95,
The outdoor fan 104 and the compressor heater 140 are connected. A memory 105 for storing programs, various data, and the like is connected to the system CPU 100.

The operation mode (cooling or heating) and the set temperature are determined by the operation unit 101 (or the remote controller), and the four-way valve 31 is switched and controlled according to the operation mode. And the electronic expansion valve 34, the indoor fan 102, the linear three-way valve 95,
The outdoor fan 104 and the like are controlled by the CPU 100.

The operation of the air conditioner of this embodiment as described above will be described together with its operation with reference to the flowchart of FIG.

First, when the main power supply of the air conditioner is turned on, initial settings of the CPUs 100 and 106 are performed, operation data such as a switch operation and data of various sensors are taken, and a driving operation is set ( Steps S1 to S
4).

Next, it is determined whether or not the operation is stopped, that is, whether or not the main power supply is turned off (step S).
5) If it is determined that the motor is stopped, the process proceeds to step S8, and the compressor heater 140 is turned on as necessary. As a result, the compressor 20 is heated by the heater, and the so-called stagnation phenomenon in which the refrigerant condenses in the compressor 20 during stoppage is suppressed. The specific control of the heater 140 will be described later in detail.

If it is determined in step S5 that the vehicle is not in the stop state, it is further determined whether the setting is the cooling operation (step S6). Here, when it is determined that the operation is the cooling operation, the following cooling operation control is performed (step S9).

That is, the four-way valve 31 is controlled so as to connect the discharge side line 41 and the line 65 and connect the suction side line 42 and the line 70 as shown by a broken line in FIG. Thereby, the high-temperature, high-pressure refrigerant discharged from the compressor 20 is, as shown by the dashed arrow in FIG.
Discharge side line 41, four-way valve 31, line 65, line 6
5, outdoor heat exchanger 32, line 66, line 75, electronic expansion valve 34, indoor heat exchanger 33, line 74, line 7
0, the four-way valve 31 and the suction side line 42 are returned to the compressor 20 in this order. Accordingly, the outdoor heat exchanger 32 functions as a condenser and radiates heat here, and the indoor heat exchanger 33 functions as an evaporator and heat is absorbed therein to cool the room.

On the other hand, when it is determined in step S6 that the operation is not the cooling operation, that is, in the case of the heating operation, the following heating operation control is performed (step S7).

During the heating operation, the four-way valve 31 is controlled to connect the discharge side line 41 and the line 70 and connect the suction side line 42 and the line 65 as shown by a solid line in FIG. As a result, the high-temperature, high-pressure refrigerant discharged from the compressor 20 is discharged by the discharge line 41, the four-way valve 31, the line 70, the line 74, the indoor heat exchanger 33, and the electronic expansion as indicated by the solid arrows in FIG. It returns to the compressor 20 through the valve 34, the line 75, the line 66, the outdoor heat exchanger 32, the line 65, the four-way valve 31, and the suction side line 42 in this order. Therefore, the indoor heat exchanger 33 functions as a condenser and radiates heat here to heat the room, and the outdoor heat exchanger 32 functions as an evaporator and heat is absorbed here.

FIG. 6 is a flowchart showing the specific control of the compressor heater 140 performed in step S8 of FIG.

In this control, first, the high pressure side pressure sensor 8
The saturation temperature of the refrigerant in the compressor 20 is determined based on the detected pressure value obtained in step S1 (step S11). In this case, for example, the pressure of the refrigerant and the corresponding saturation temperature are stored in the memory 105 in advance as a table, and the saturation temperature is obtained from this table based on the pressure detected by the pressure sensor 81.

Next, the lower one of the temperatures detected by the compressor temperature sensors 24 and 25 is compared with the above-mentioned saturation temperature, and the temperature of the compressor 20 is calculated by adding a predetermined safety value α to the saturation temperature of the refrigerant. It is determined whether the temperature has exceeded
(Step S12). In addition, the safety value α is such that the value (temperature) obtained by adding the safety value α to the saturation temperature of the refrigerant is the temperature of the compressor 20 when the refrigerant in the compressor 20 is at the saturation temperature. It is set in consideration of heat capacity and the like.

Then, in step S12, when it is determined that the compressor temperature does not exceed the above-mentioned temperature, that is, since the temperature of the refrigerant in the compressor 20 does not exceed the saturation temperature, the refrigerant is easily condensed. If it is determined that there is, the heater 140 is turned on and the compressor 20 is heated. When the compressor 20 is heated in this way, the refrigerant in the compressor 20 is indirectly heated, and the condensation of the refrigerant while the compressor is stopped is suppressed.

On the other hand, when it is determined that the compressor temperature exceeds the above temperature, that is, when it is determined that the temperature of the refrigerant in the compressor 20 exceeds the saturation temperature, the heater 140 is turned off. You. This prevents unnecessary heating of the compressor 20.

According to the air conditioner described above, when the air conditioner is stopped, the heater 140
Is operated to heat the compressor 20, thereby the compressor 2
Since the refrigerant in the zero is heated, it is possible to effectively prevent the so-called refrigerant stagnation phenomenon in which the refrigerant condenses during the stop and stays in the compressor 20.

Further, the heater 140 is not always operated, but is operated based on the detected refrigerant pressure on the high pressure side.
The saturation temperature of the refrigerant in the compressor is determined, and the heater 140 is turned on and off while checking the state in which the temperature of the refrigerant in the compressor 20 is equal to or lower than the saturation temperature, that is, the state in which the refrigerant is easily condensed. As described above, it is possible to reduce the power consumption due to the heating of the heater while preventing the occurrence of the refrigerant stagnation phenomenon. In particular, when the main power supply is turned off after the cooling operation or the heating operation, the refrigerant pressure in the compressor 20 gradually decreases, and the saturation temperature of the refrigerant decreases accordingly. The amount of heat will also change with this, but by controlling the heater 140 on and off while checking the saturation temperature of the refrigerant and checking the state in which the refrigerant is likely to condense as in the above embodiment,
The heater 1 responds to the change of the required heat amount with time as described above.
40 can be activated. Therefore, the heater 14
0 operation can be minimized.

The air conditioner described above is one embodiment of an air conditioner to which the heating device for a compressor according to the present invention is applied, and the specific configuration thereof does not depart from the gist of the present invention. Can be changed as appropriate.

For example, in the above-described air conditioner, the above-described heater control is executed when the main power supply is turned off. Compressor 2 when it reaches
0 may stop and a stagnation phenomenon of the refrigerant may occur. Therefore, even during the cooling operation or the like, the above-described heater control may be executed when the compressor 20 is stopped.

In the above embodiment, the ejection side line 4
The refrigerant pressure is detected by the high-pressure side pressure sensor 81 provided in the compressor 1, and the saturation temperature of the refrigerant in the compressor 20 is obtained based on the detected pressure. By installing a pressure sensor in the reservoir 123, the refrigerant pressure in the compressor 20 may be directly detected.

Further, in the above embodiment, the refrigerant is indirectly detected by detecting the temperature of the compressor 20 and comparing the value obtained by adding the safety value α to the saturation temperature and the temperature of the compressor 20 as described above. Although a state in which condensation is likely to occur is checked, a temperature sensor is installed in the oil reservoir 123 of the compressor 20 to directly detect the refrigerant temperature in the compressor 20, and the detected temperature and the obtained saturation temperature May be compared. According to this, the state in which the refrigerant is easily condensed can be detected more accurately, and the occurrence of the refrigerant stagnation phenomenon can be more reliably prevented. In this case, if the pressure sensor is installed in the compressor 20 as described above and the refrigerant pressure in the compressor 20 is directly detected, and the saturation temperature is obtained based on the refrigerant pressure, the refrigerant stagnation phenomenon can be prevented. Generation can be prevented more reliably.

The heater control according to the above embodiment is an example suitable for a case where only one type of refrigerant circulates in the refrigerant circuit 30. The refrigerant mixture in which a plurality of types of refrigerant are mixed is circulated in the refrigerant circuit 30. In such a case, since the saturation temperature varies depending on the type of the refrigerant, it is preferable to configure, for example, as follows. That is, for example, a composition ratio sensor (composition ratio detecting means) for detecting the composition ratio of the refrigerant constituting the mixed refrigerant is installed in the compressor 20, and the composition ratio of each refrigerant of the mixed refrigerant detected by the composition ratio sensor and the high pressure side are detected. The partial pressure of each refrigerant is obtained from the pressure detected by the pressure sensor 81, and the saturation temperature of each refrigerant is obtained from the partial pressure. The highest saturation temperature among the saturation temperatures of each refrigerant and the detection temperatures of the compressor temperature sensors 24 and 25 are obtained. It may be determined whether or not the refrigerant is in a state in which the refrigerant easily condenses. With this configuration, the heater 140 is turned on and off based on the refrigerant having the highest saturation temperature among the refrigerants forming the mixed refrigerant, and therefore, as for the device using the mixed refrigerant, similarly to the device of the above embodiment, It is possible to prevent the stagnation phenomenon of the refrigerant while minimizing the operation of the heater to a necessary minimum.

In the above-described embodiment, an example in which the present invention is applied to an air conditioner which is a kind of a refrigerant circulating heat transfer device has been described. However, the present invention is not limited to an air conditioner, such as a refrigerator (including a refrigerator). It is also applicable to a refrigerant circulation type heat transfer device such as the one described above.

[0058]

As described above, the present invention prevents the occurrence of the refrigerant stagnation phenomenon by heating the compressor while the compressor is stopped, while detecting the refrigerant pressure and the like in the compressor and the refrigerant temperature. Then, the saturation temperature of the refrigerant in the compressor is obtained based on the refrigerant pressure and the like, and the saturation temperature is compared with the detected refrigerant temperature to determine a state in which the refrigerant is easily condensed. Since the heater operation is minimized by operating only the heater, the power consumption due to heater heating can be effectively suppressed while effectively preventing the refrigerant stagnation phenomenon. it can.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a refrigerant circulation heat transfer device (air conditioner) to which the present invention is applied.

FIG. 2 is a sectional view showing a configuration of a compressor.

FIG. 3 is a sectional view taken along line AA of FIG. 2 showing the compressor.

FIG. 4 is a block diagram showing a control system of the refrigerant circulation type heat transfer device.

FIG. 5 is a flowchart illustrating an example of operation control of the refrigerant circulation heat transfer device.

FIG. 6 is a flowchart illustrating an example of control of a compressor heater.

[Explanation of symbols]

1a Outdoor unit 1b Indoor unit 2 Engine 20 Compressor 24, 25 Compressor temperature sensor (Temperature detecting means) 30 Refrigerant circuit 32 Outdoor heat exchanger 33 Indoor heat exchanger 34 Electronic expansion valve 81 High pressure side pressure sensor (Pressure detecting means) 82 Low pressure side pressure sensor 100 System CPU (control means, saturation temperature calculation means) 106 Engine CPU 140 Compressor heater

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F25B 1/00 351 F25B 1/00 351V 27/00 27/00 B

Claims (3)

[Claims] 1. A heating device for a compressor applied to a refrigerant circulation type heat transfer device configured to circulate a refrigerant discharged from a compressor to a predetermined refrigerant circuit, wherein the heater heats the compressor. Pressure detection means for detecting a refrigerant pressure in the compressor or a pressure related to the pressure, temperature detection means for detecting a refrigerant temperature in the compressor or a temperature related to the temperature, and detection by the pressure detection means Saturation temperature calculating means for calculating the saturation temperature of the refrigerant in the compressor based on the pressure, and comparing the calculated saturation temperature with the temperature detected by the temperature detecting means to determine a state in which the refrigerant is easily condensed, Control means for controlling the heater to heat the compressor when the compressor is stopped and the refrigerant in the compressor is easily condensed. 2. The temperature detecting means detects the temperature of the compressor, and the control means compares a value obtained by adding a safety value considering a heat capacity of the compressor to the saturation temperature and the detected temperature of the compressor. The heating device for a compressor according to claim 1, wherein the heating device is configured to determine a state in which the refrigerant is easily condensed. 3. The refrigerant-circulating heat transfer device circulates a mixed refrigerant in which a plurality of types of refrigerant are mixed,
Having a composition ratio detection means capable of detecting the composition ratio of the mixed refrigerant,
The saturation temperature calculation means is configured to obtain a saturation temperature for each type of refrigerant based on the detected pressure by the pressure detection means and the composition ratio detected by the composition ratio detection means, and the control means 3. The compressor heating device according to claim 1, wherein a state in which the refrigerant is easily condensed is determined based on the highest saturation temperature among the types of saturation temperatures.