JP3239494B2 - Refrigeration equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus used for an air conditioner, a refrigerator and the like, and more particularly to a refrigerating apparatus which can use different refrigerants.

[0002]

2. Description of the Related Art As described in Japanese Patent Publication No. 2-45796 and Japanese Patent Laid-Open Publication No. 230055, for example, the control of a refrigeration system used in an air conditioner, a refrigerator or the like is performed by controlling a refrigeration cycle. There is known a method of detecting the temperature and pressure of each part and controlling the expansion valve from the detected values and data stored in a control unit. Further, as described in JP-A-2-230054, the temperature and pressure of each part of the refrigeration cycle are detected, and the detected values are compared with the data stored in the control unit to determine the abnormality of the refrigeration cycle. There are known ways to do this.

[0003]

In the above conventional example, no consideration is given to the case where the type of refrigerant changes.
In recent years, refrigerants used in refrigeration systems, for example, R1
It has become clear that chlorine-containing refrigerants such as 2, R22 destroy the ozone layer, and are in the direction of being banned. Instead of these refrigerants, R12
R134a for R22 and R32 and R134 for R22
A mixed refrigerant of a or a mixed refrigerant of R32 and R125 is known as an alternative refrigerant. However, when an already installed refrigeration unit replaces a refrigerant that has been enclosed due to relocation or failure with a substitute refrigerant, the refrigeration unit does not operate normally with the conventional control constants due to the different characteristics of the refrigerant. There was a problem.

Further, since the substitute refrigerant does not contain chlorine, the refrigerating machine oil used for R12 and R22 is not compatible with the refrigerating machine oil, and the refrigerating machine oil flowing out of the compressor hardly returns to the compressor. Therefore, there is a problem that poor lubrication of the compressor occurs.

An object of the present invention is to provide a refrigeration apparatus that can perform normal control even when different refrigerants are charged.

[0006]

SUMMARY OF THE INVENTION The object of the present invention is to provide a compressor,
Refrigeration consisting of connecting a contractor, expansion valve, and evaporator
Cycle and charging and discharging of refrigerant into the refrigeration cycle
Service valve that can perform
Detector for detecting the operating condition of the vehicle and the signal from this detector
And the cooling based on the data stored in the storage device.
A refrigeration system equipped with a controller for operating the refrigeration cycle
And can be enclosed in the refrigeration cycle in the storage device.
Stores data corresponding to multiple refrigerants and stores these data
Data used for the operation of the refrigeration cycle
Selection means. Also,
The above purpose is to connect compressor, condenser, expansion valve and evaporator.
Refrigeration cycle consisting of
A service valve that can charge and discharge refrigerant
Detector for detecting the discharge temperature of refrigerant discharged from compressor
And the signal from this detector and stored in the storage device.
Controller for adjusting the opening of the expansion valve based on the data
And a refrigeration apparatus comprising:
Data corresponding to multiple refrigerants that can be enclosed in the cycle
The opening degree of the expansion valve is adjusted from these data.
Means for selecting data used to save
Is achieved by Achieved by providing.

[0007]

According to the present invention, by providing a means for changing the data in the storage device of the refrigerating apparatus according to the refrigerant used, a control constant corresponding to the type of the refrigerant can be used even when the refrigerant is changed. The cycle can be operated normally.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described using an air conditioner as an example of a refrigerating apparatus.

FIG. 1 is a control circuit diagram of an air conditioner according to an embodiment of the present invention, FIG. 2 is a system diagram of a refrigeration cycle of the air conditioner according to an embodiment of the present invention, and FIG. 3 is a refrigerant of an outdoor heat exchanger. It is a temperature distribution diagram.

In FIG. 1, reference numeral 1 denotes an outdoor controller, which is an inverter circuit for controlling the number of revolutions of a compressor 3, a four-way valve 5,
Four-way valve drive device that switches between cooling operation and heating operation 4,
An outdoor fan drive 6 for driving the outdoor fan 7, an expansion valve drive 8 for driving the expansion valve 9, and a discharged refrigerant temperature detector 1
0, an outdoor heat exchanger temperature detector 11, an intake refrigerant temperature detector 12, an outdoor air temperature detector 13, a first storage device 14 storing control constants and the like that differ depending on refrigerant physical properties, and a second storage device 14. A storage device changeover switch 14 for switching the storage device 15 is provided. The second storage device 15 stores oil return operation data at regular operation time intervals in addition to control constants. The storage device changeover switch 14 is set on the side of the first storage device 14 that matches the refrigerant sealed in advance, for example, R22. Reference numeral 17 denotes an indoor controller, which is an operating device 1 for inputting an operation mode or a set temperature.
8. Indoor fan drive 1 for driving indoor fan 20
9, an indoor heat exchanger temperature detector 21, an indoor air temperature detector 22, and an indoor blowout air temperature detector 23 are provided.
The indoor controller 17 and the outdoor controller 1 can transfer data bidirectionally, and transfer the operation mode, the output of each detector, and the like.

In FIG. 2, reference numeral 5 denotes an outdoor unit,
A compressor 3, a four-way valve 5 for switching the flow direction of the refrigerant between the cooling operation and the heating operation, an outdoor fan 7 for blowing an outdoor heat exchanger 25 acting as a condenser during the cooling operation and an evaporator during the heating operation, and expansion. A valve 9, an accumulator 26, and a service valve 27 for charging and discharging the refrigerant in the refrigeration cycle are provided. An indoor unit 28 is provided with an indoor fan 20 that blows air to an indoor heat exchanger 29 that functions as an evaporator during cooling operation and a condenser during heating operation. The indoor unit 28 and the outdoor unit 24 are connected by a gas side pipe 30 and a liquid side pipe 31.

The operation of the air conditioner configured as described above will be described.

When the controller 18 is set to the cooling operation, the indoor fan 20 is turned on, and the indoor controller 17 sends the outdoor controller 1 a cooling operation mode, and detects the set temperature of the indoor unit and the indoor air temperature at regular intervals. The temperature difference detected by the heater 22 is transferred. By the outdoor controller 1, the four-way valve 4 is set on the cooling operation side and the outdoor fan 7 through the outdoor fan driving device 6.
Is turned on, the expansion valve 9 is set to the opening degree based on the preset data in the first storage device 15 by the expansion valve driving device 8, and the compressor 3 is set to the temperature difference sent from the indoor controller 17. And the rotation speed calculated from the data stored in the first storage device 15.

The high-temperature and high-pressure gas refrigerant discharged from the compressor 3 passes through the four-way valve 5 and radiates heat to the air blown by the outdoor fan 7 in the outdoor heat exchanger 25 to condense. The condensed liquid refrigerant is decompressed by the expansion valve 9 to become a gas-liquid two-phase refrigerant, and is sent to the indoor unit 28 through the liquid side pipe 31. The refrigerant sent to the indoor unit 28 cools the air blown by the indoor fan 20 in the indoor heat exchanger 29, turns into a gas refrigerant, passes through the gas side pipe 30, returns to the outdoor unit 24, and returns to the four-way valve 5, the accumulator. The flow returns to the compressor 3 through 26. After the opening degree of the expansion valve 9 is kept at the set value for a certain period of time, the compressor discharge refrigerant temperature detected by the discharge refrigerant temperature detector 10 is lower than the preset temperature stored in the first storage device 15 in advance. Is controlled to a value stored in the first storage device 10 based on the temperature difference of the outdoor air temperature detector 13 and the compressor rotation speed. When the temperature detected by the discharged refrigerant temperature detector 10 is higher than the set temperature, the opening is controlled so that the discharged refrigerant temperature becomes the set value. A part of the refrigerating machine oil enclosed in the compressor 3 flows out into the refrigerating cycle with the outflow of the refrigerant, but the enclosed refrigerating machine oil is compatible with the refrigerant and has a viscosity due to melting with the refrigerant. Drops and returns to the compressor by the flow of refrigerant.

When the temperature detected by the outdoor heat exchanger temperature detector 11 becomes higher than a preset temperature stored in the storage device 15, the compressor 3 is stopped to prevent overload of the compressor. You.

Next, the heating operation will be described. When the operation mode of the operation device 18 is set to the heating operation, the indoor controller 17
From this, the heating operation mode and the difference between the set temperature of the indoor unit and the temperature difference detected by the indoor air temperature detector 22 are transferred to the outdoor controller 1 at regular intervals. The outdoor controller 1 sets the four-way valve 5 to the heating operation side, sets the outdoor fan 7 to ON, sets the expansion valve 9 to the opening degree stored in the first storage device 15, and sets the compressor 3 to the required rotation speed. While being driven, the compressor 3 is driven at the rotation speed calculated from the data stored in the first storage device 15 from the temperature difference sent from the indoor controller 17. The indoor fan 20 is driven when the temperature detected by the indoor heat exchanger temperature detector 21 exceeds a set value in order to prevent cool air.

During the heating operation, the compressor 3
The high-temperature and high-pressure gas refrigerant that has exited
To the indoor unit 28. Indoor unit 28
Is heated by the indoor heat exchanger 29 to heat the air blown by the indoor fan 20, turns into a liquid refrigerant, passes through the liquid-side pipe 31, returns to the outdoor unit 24, and returns to the outdoor heat exchanger 25. It absorbs more heat and becomes a gas refrigerant, and the four-way valve 5,
It returns to the compressor 3 through the accumulator 26. After the opening degree of the expansion valve 9 is kept at the set value stored in the first storage device 15 for a certain period of time, if the compressor discharge refrigerant temperature detected by the discharge refrigerant temperature detector 10 is lower than the set temperature, The opening is controlled so that the temperature difference between the suction refrigerant temperature detector 12 and the outdoor heat exchanger temperature detector 11 becomes a value stored in the first storage device. The temperature distribution of the outdoor heat exchanger 25 at this time will be described with reference to FIG. With a single refrigerant such as R22, the refrigerant flowing into the outdoor heat exchanger 25 flows while evaporating in the pipe, but the refrigerant temperature slightly decreases due to pressure loss. Outdoor heat exchanger temperature detector 1 installed at position X1
1, the outdoor heat exchanger temperature T1 is detected. The refrigerant further continues to evaporate and finishes evaporating at the position X2, becomes superheated steam, exits the outdoor heat exchanger, and returns to the compressor. At this time, the suction refrigerant temperature detector 1 provided at the position X3 immediately before the compressor inlet
2, the compressor suction refrigerant temperature T2 is detected. By controlling the expansion valve 9 so that the difference between the suction refrigerant temperature T2 and the outdoor heat exchanger temperature T1 becomes a value stored in the first storage device 15, the air conditioner is operated with high efficiency. . When the temperature detected by the discharged refrigerant temperature detector 23 is higher than the set temperature, the expansion valve is controlled so that the discharged refrigerant temperature becomes the set value, and a decrease in reliability due to overheating of the compressor 3 can be prevented. When the temperature detected by the indoor heat exchanger temperature detector 21 becomes higher than a set temperature stored in the storage device 15 in advance, the compressor 3 is stopped to prevent the compressor from being overloaded.

Here, when a different refrigerant is introduced due to a failure or the like, the service valve 27 is opened, the enclosed refrigerant is recovered, and the refrigerant is evacuated.
A mixed refrigerant containing 30 wt% of R2 and 70 wt% of R134a is sealed from the service valve 27. Further, the second storage device 16 is selected by the storage device changeover switch 14. The expansion valve control during the heating operation at this time will be described with reference to FIG. The mixed refrigerant flowing into the outdoor heat exchanger 25 evaporates along the pipe, and the temperature rises due to the characteristics of the mixed refrigerant.
The outdoor heat exchanger temperature T3 is detected by the outdoor heat exchanger temperature detector 11 installed at the position X1. The refrigerant further continues to evaporate and finishes evaporating at the position X2, becomes superheated steam, exits the outdoor heat exchanger, and returns to the compressor. At this time, a suction refrigerant temperature T4 is detected by a suction refrigerant temperature detector 12 provided at a position X3 immediately before the compressor inlet. This suction refrigerant temperature T4
The air conditioner is normally operated by controlling the expansion valve 9 so that the difference between the temperature and the outdoor heat exchanger temperature T2 becomes a value stored in the second storage device 16. Furthermore, by using the value stored in the second storage device as the set value of the expansion valve at the time of starting or the like, transient fluctuation is reduced.

Further, the second storage device 16 stores data for performing the oil recovery operation at every predetermined time. When the operation time of the compressor 3 detected by the outdoor control device 1 reaches the time stored in the second storage device 16, the oil return operation is started. The operation will be described with reference to the time chart of the oil return operation in FIG. The operation of the compressor 3 is performed for a certain time Δt1.
, The compressor 3 is set to the high-speed rotation number stored in the second storage device 16 and the expansion valve 9 is fully opened regardless of the operation state of the refrigeration cycle.

Since the compressor 3 is operated at a high speed and the expansion valve 9 is opened, the refrigerant flowing out of the compressor 3 circulates in the refrigeration cycle at a high speed. At this time, the refrigerating machine oil that has flowed out of the compressor during the normal operation and has been separated from the refrigerant and stayed in the refrigeration cycle is returned to the compressor by the refrigerant circulating at high speed. When the oil return operation Δt2 elapses, the operation returns to the normal operation.

The set values stored in the second storage device 16 are used for the temperature of the indoor heat exchanger at which the compressor stops during the cooling operation and the temperature of the outdoor heat exchanger during the heating operation.

As described above, according to this embodiment, even when a different refrigerant is replaced, normal operation can be performed by changing data in the storage device. Further, since the oil return operation is performed at regular intervals of the compressor, even if a refrigerant which is not compatible with the conventionally enclosed refrigerating machine oil is used, poor lubrication due to lack of refrigerating machine oil in the compressor does not occur. Further, by changing the data of the set temperature provided for protecting the compressor, it is possible to prevent the compressor from being overloaded even if refrigerants having different evaporation pressure characteristics are used. In the case of refrigerants having greatly different characteristics, normal operation is possible by changing the relationship between the compressor speed and the capacity or changing the data of the compressor speed and the applied voltage.

In this embodiment, the first storage device and the second storage device are provided by the refrigerant. However, data of different refrigerants may be stored in one storage device, and may be switched by a storage device changeover switch. . Furthermore, instead of using a changeover switch, a removable storage device such as an IC card is provided on the mounted base, and when a different refrigerant is charged, a storage device storing data of the refrigerant to be charged is mounted. The same effect can be obtained also by the above.
In this case, the data in the storage device can be changed depending on the alternative refrigerant to be sealed, and there is an advantage that it is not necessary to determine a specific alternative refrigerant when manufacturing the air conditioner. Further, during the oil return operation, the expansion valve is fully opened to increase the rotation speed of the compressor. However, in a compressor in which the rotation speed of the compressor is fixed, even if the expansion valve is fully opened, the oil recovery effect can be obtained. .

Another embodiment of the present invention will be described with reference to FIGS.

FIG. 5 is a control circuit diagram of an air conditioner according to another embodiment of the present invention. FIG. 6 is a refrigeration cycle diagram of an air conditioner according to another embodiment of the present invention. FIG. 7 is a time chart during the oil recovery operation.

In FIG. 5, reference numeral 32 denotes an oil recovery operation switch provided in the outdoor controller 1.

In FIG. 6, reference numeral 33 denotes an oil release valve provided at the lower part of the hermetic compressor 3 in which a motor unit and a compression element are incorporated and refrigeration oil is sealed at the lower part, and reference numeral 34 denotes an oil fill valve provided at the upper part of the compressor.

The operation of the air conditioner configured as described above will be described.

During the cooling and heating operations, the same operation as in the above embodiment is performed. The operation when it is necessary to replace the refrigerant will be described with reference to FIG.

When the oil recovery switch 32 is turned on, the compressor 3 is operated at a high speed and the expansion valve 9 is fully opened based on the data stored in the first storage device 15. Further, the outdoor fan 7 and the indoor fan 20 are turned on. The four-way valve 5 is on the heating operation side. After a lapse of Δt1 time, the compressor 3 rotates at a low speed, and the expansion valve 9 is controlled so that the temperature difference detected by the outdoor heat exchanger temperature detector 11 and the refrigerant suction temperature detector 12 becomes a set value. . After the elapse of Δt2, the compressor and the like are stopped, and the oil recovery operation is terminated. Since the compressor 3 is initially operated at a high speed, a large amount of the refrigerant circulates in the refrigeration cycle, and even if the refrigeration oil stays in the refrigeration cycle, it is recovered in the compressor in a short time. In addition, by operating the compressor 3 at low speed rotation after high speed operation, the amount of refrigerating machine oil flowing out from the compressor 3 decreases,
The refrigerating machine oil flowing out together with the refrigerant during the high-speed operation of the compressor is also dissolved in the refrigerant and returns to the compressor. Therefore, most of the refrigerating machine oil flowing into the refrigerating cycle is recovered by the compressor. In this state, the refrigerant and oil drain valve 3
3 is evacuated from the service valve 27, and refrigeration oil for alternative refrigerant is supplied from the oil filling valve 34;
For example, the same operation as the embodiment can be performed by enclosing an ester oil and enclosing an alternative refrigerant after evacuation.

As described above, according to the present embodiment, it is possible to replace the refrigerating machine oil in the compressor with that for the alternative refrigerant. Further, by performing the refrigerating machine oil recovery operation before replacing the refrigerating machine oil, old refrigerating machine oil can be reduced as much as possible.

In the above-described embodiment, an air conditioner having one indoor unit for one outdoor unit has been described as a refrigerating device. However, the present invention provides a plurality of units for one outdoor unit. It can be used for all refrigeration systems of the type that compresses refrigerant such as an air conditioner having an indoor unit or a refrigerator.

[0033]

According to the present invention, by providing means for changing the data in the storage device of the refrigerator according to the refrigerant used, normal control can be performed even when a different refrigerant is charged.

[Brief description of the drawings]

FIG. 1 is a block diagram of an air conditioner according to an embodiment of the present invention.

FIG. 2 is a system diagram of a refrigeration cycle of the air conditioner according to the embodiment of the present invention.

FIG. 3 is a temperature distribution diagram of the outdoor heat exchanger.

FIG. 4 is a time chart during an oil return operation.

FIG. 5 is a control circuit diagram of an air conditioner according to another embodiment of the present invention.

FIG. 6 is a system diagram of a refrigeration cycle of an air conditioner according to another embodiment of the present invention.

FIG. 7 is a time chart during an oil recovery operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Outdoor controller, 3 ... Compressor, 5 ... Four-way valve, 9 ... Expansion valve, 10 ... Discharge refrigerant temperature detector, 11 ... Outdoor heat exchanger temperature detector, 12 ... Suction refrigerant temperature detector, 14 ... Storage device changeover switch, 15: first storage device, 16: second storage device, 17: indoor controller.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kensaku Oguni 502 Kandate-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. In-house (56) References JP-A-62-228839 (JP, A) JP-A-1-256765 (JP, A) JP-A-3-168566 (JP, A) JP-A-63-311061 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F25B 1/00

Claims (2)

(57) [Claims] 1. A compressor, a condenser, an expansion valve, and an evaporator are connected .
Refrigeration cycle consisting of
A service valve that can charge and discharge refrigerant into the
In refrigeration system including a detector for detecting each part of the operating conditions in the freezing cycle, and a controller that performs the operation of the refrigeration cycle signal and on the basis of the data stored in the storage device from the detector, the This cold storage
Data corresponding to multiple refrigerants that can be enclosed in the freeze cycle
And from these data, the refrigeration cycle
Means for selecting data used for operation . 2. A refrigeration cycle constituted by connecting a compressor, a condenser, an expansion valve, and an evaporator; a service valve capable of charging and discharging a refrigerant into the refrigeration cycle; A refrigerating apparatus comprising: a detector that detects a discharge temperature of refrigerant to be discharged; and a controller that adjusts an opening degree of the expansion valve based on a signal from the detector and data stored in a storage device. Means for storing data corresponding to a plurality of refrigerants that can be sealed in the refrigeration cycle in the storage device, and selecting data used for adjusting the degree of opening of the expansion valve from the data. Refrigeration equipment.