JPS602538Y2 - Refrigeration cycle overload control device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an overload control device for a refrigeration cycle that constitutes a dual-purpose air conditioner.

In conventional air conditioners that can be used for both cooling and heating, the cooling capacity is too large compared to the heating capacity when used in the same room. The capacity was adjusted by controlling the operating time of the compressor using a temperature controller, which may not be sufficient for safety or cooling sensation, and if the temperature on the heat source side rises during heating operation, the load on the compressor may become excessive. This has disadvantages such as requiring an operation to stop the fan for the heat exchanger on the heat source side.

Therefore, the present invention solves the drawbacks of the conventional control described above, and controls the cooling capacity in three stages and the heating capacity in two stages, so that the optimal air conditioning effect can always be obtained. It is something.

Hereinafter, the present invention will be described with reference to the accompanying drawings showing one embodiment thereof.

In the figure, 1 is a rotary compressor, and an electric motor 3 and a compression mechanism section 4 are disposed inside a closed container 2.

The compression mechanism section 4 closes the cylinder 5 and both end surfaces of the cylinder 5, and also includes a bearing end plate (not shown) that supports the rotating shaft 6.
and a piston 8 that eccentrically rolls inside the cylinder 5 as the rotating shaft 6 rotates.The piston 8 is slidably fitted into a partition groove 9 provided in the cylinder 5 and is biased by a spring 10 so that one end is always in contact with the piston 8. partition plate 11, and the cylinder 5
A suction hole 12, an intermediate discharge hole 13, and a discharge hole 14 are provided in this order from the partition groove 9 toward the rotational direction of the rotating shaft 6, respectively.

Furthermore, the suction hole 12 communicates with the outside of the closed container 2, the intermediate discharge hole 13 communicates with the outside of the closed container 2 via an intermediate discharge valve 15 and an intermediate discharge passage 16, and the discharge hole 14 communicates with the outside of the closed container 2 through an intermediate discharge valve 15 and an intermediate discharge passage 16. It communicates with the inside of the closed container 2 via 17.

18 is a discharge pipe that communicates the inside and outside of the closed container 2.

19 is a four-way switching valve that switches the refrigerant passage during heating and cooling; 20
is the heat source side heat exchanger, 21 is the refrigeration cycle throttling device, 2
Reference numeral 2 denotes a utilization side heat exchanger, and 23 denotes a refrigerant pipe connecting the utilization side heat exchanger 22 and the four-way switching valve 19.

Reference numeral 24 denotes a flow rate restricting device, which is provided in a bypass passage 25 that communicates the refrigerant pipe 23 with the intermediate discharge passage 16, and restricts the flow rate of the refrigerant flowing therethrough, and is made of a thin tube, a pressure reducing device, or the like.

26 is a first on-off valve that opens and closes the bypass passage 25; 27 is a connection between the flow rate restriction device 24, such as a thin tube, and the intermediate discharge passage 16, via a second on-off valve 28, and the four-way switching valve 19 and the suction side of the compressor 1; This is a suction bypass path connected to the suction path 29 connecting to the suction path 29.

30 is an accumulator.

Next, the overload control operation of the refrigeration cycle having the above configuration will be explained.

The compressor 1 sucks gaseous refrigerant through the suction hole 12 as the rotating shaft 6 rotates, compresses the gaseous refrigerant in a compression space surrounded by the piston 8, the inner wall of the cylinder 5, the bearing end plate, and the partition plate 11, Normally, high-pressure refrigerant gas is discharged from the discharge hole 14 through the discharge pipe 18 through the closed container 2 via the discharge valve 17 .

In this normal operating state, when suction pressure is applied to the intermediate discharge passage 16, a portion of the compressed gaseous refrigerant is transferred to the intermediate discharge hole 13.
The air then flows through the intermediate discharge valve 15 to the accumulator 30, which is the suction side of the compressor 1.

Next, when a discharge pressure is applied to the intermediate discharge passage 16, the gaseous refrigerant is discharged from the closed container 2 through the discharge hole 14 and the discharge valve 17.

Therefore, when both on-off valves 26.2B are closed during cooling operation, the high temperature and high pressure gaseous refrigerant discharged from the compressor 1 is transferred to the heat source side heat exchanger via the four-way switching valve 19 as shown by the solid arrow. 20, the refrigerant is cooled and condensed to become a high-pressure liquid refrigerant, which is depressurized by an expansion device 21, absorbs ambient heat by a user-side heat exchanger 22, and becomes a low-pressure gas refrigerant.

Then, it returns to the compressor 1 via the four-way switching valve 19.

In this cooling operating state, when only the first on-off valve 26 is opened, the intermediate discharge passage 16 is connected to the flow rate restricting device 24 made of a thin tube or the like.
A part of the gaseous refrigerant compressed in the cylinder 5 is communicated with the low-pressure side refrigerant pipe 23 through the intermediate discharge hole 13 to the intermediate discharge valve 1.
The refrigerant is bypassed to the suction side of the compressor 1 together with the refrigerant flowing from the user-side heat exchanger 22 with its flow rate being restricted by the flow rate restriction device 24 via the refrigerant 5 .

Therefore, since the amount of refrigerant circulation is reduced, the cooling capacity is slightly reduced.

On the other hand, when only the second on-off valve 28 is opened during normal cooling operation, the intermediate discharge passage 16 communicates with the suction passage 29, and a portion of the gaseous refrigerant compressed in the cylinder 5 flows from the intermediate discharge hole 13 to the intermediate discharge passage 16. The air is directly bypassed to the suction side of the compressor 1 via the discharge valve 15, and the cooling capacity is greatly reduced.

When the second on-off valve 28 is open, the refrigerant circulation amount does not change even if the first on-off valve 26 is opened, so the capacity does not change.

Next, during heating operation, when both the on-off valves 26 and 28 are closed, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 undergoes heat exchange on the user side via the four-way switching valve 19 as shown by the broken line arrow. The refrigerant radiates heat and condenses in the refrigerant 22, is depressurized in the throttle device 21, absorbs heat in the heat source side heat exchanger 20, becomes a low-pressure gas refrigerant, and returns to the compressor 1 through the four-way switching valve 19.

In this heating operation state, when only the second on-off valve 28 is opened, the intermediate discharge passage 16 is communicated with the suction passage 29, and a part of the gaseous refrigerant compressed in the cylinder 5 flows from the intermediate discharge hole 13 to the intermediate discharge valve 15. The air is bypassed to the suction side of the compressor 1 through the air.

Therefore, the amount of refrigerant circulated is drastically reduced, and the heating capacity is drastically reduced.

Furthermore, when both on-off valves 26 and 28 are opened at the same time, compressor 1
A portion of the high-pressure gas discharged flows to the suction side of the compressor 1 through the bypass path 25 equipped with the flow restriction device 24, so the heating capacity is further reduced compared to when only the second on-off valve 28 is opened. .

Even if only the first on-off valve 26 is opened during heating operation, the compressor 1
Since the suction side of the
does not flow and the heating capacity does not change.

Therefore, for example, in the case of an air conditioner that does not use a heater during heating, the input during cooling can be prevented from becoming excessive by opening the first on-off valve 26 during cooling operation.

Additionally, in the past, when the air conditioning function capacity was greater than the cooling/heating load during cooling/heating, the compressor was frequently turned on and off using a temperature controller, etc. to limit the capacity of the air conditioner. According to , the temperature fluctuation of the user-side heat exchanger 22 is large and increases discomfort, but the second on-off valve 28
If the control is open, the heating and cooling capacity will be drastically reduced, so the compressor will not be turned on and off frequently, and therefore the temperature fluctuation of the heat exchanger 22 on the user side will be eliminated, causing discomfort. Less is.

Furthermore, when the load is heavy during heating operation and an excessive load is applied to the compressor 1, conventionally, the fan (not shown) of the heat source side heat exchanger 20 is stopped, etc. to exchange heat in the heat source side heat exchanger 20. Although the amount was limited, according to this embodiment, the load on the compressor 1 can be reduced simply by opening the on-off valve 28.

That is, during cooling operation, heating operation, etc., the indoor temperature, outdoor temperature, pressure during the refrigeration cycle, etc. (any one as necessary) are detected by an appropriate detection device (not shown), and the temperature or pressure is first detected. When the first set value is reached, the first on-off valve 26 opens during cooling to perform capacity control, and if the temperature or pressure returns to the original value in this state, the first on-off valve 26 opens.
The on-off valves 26 and 28 may be controlled to open and close so that when the temperature or pressure reaches the second set value with the first on-off valve 26 closed and the temperature or pressure reaching the second set value, the second on-off valve 28 opens. (In this case, it is preferable that the first on-off valve 26 is closed).

In addition, during heating, the indoor temperature, outdoor temperature, pressure during the refrigeration cycle, etc. (any one as necessary) are similarly detected by the above-mentioned appropriate detection device, and when the temperature or pressure reaches the first set value, , the second on-off valve 28 opens to reduce the amount of refrigerant circulation to perform capacity control, and if the temperature or pressure returns to the original level in this state, the second on-off valve 28 closes.

Further, when the temperature or pressure further reaches the second set value while the second on-off valve 28 is open, the first on-off valve 26 also opens, further reducing the performance.

Therefore, when the rotary compressor 1 is operating during cooling and heating, the amount of refrigerant circulation (refrigerant discharge amount) is controlled in multiple stages, so fine capacity control can be performed, and the rotary compressor 1 1 is not frequently operated intermittently, no sudden temperature changes are felt, good cooling and heating effects can be obtained, and input during cooling can be reduced.

Incidentally, the present invention can be similarly implemented in a rotary compressor having a configuration in which the vane lla is provided on the histone 8 as shown in FIG.

As is clear from the above embodiments, the refrigeration cycle overload control device of the present invention uses a rotary compressor, a four-way switching valve, a user side heat exchanger, a heat source side heat exchanger, and a pressure reducing device. The rotary compressor is equipped with a cylinder and a piston, and is provided with an intermediate discharge hole that opens midway through the compression stroke into the compression space of the cylinder. An intermediate discharge passage communicating with the outside of the machine is provided, and one end of the refrigeration cycle is connected between the user-side heat exchanger and the four-way switching valve, and the other end is connected to the intermediate discharge passage. A bypass path is provided, a first on-off valve is provided in the bypass path, and the first on-off valve is provided in the bypass path.
A suction bypass path is provided between the on-off valve and the intermediate discharge valve and connected to the suction path side of the compressor via a second on-off valve, and by opening only the first on-off valve, the cooling capacity can be increased. By opening only the second on-off valve, the capacity during cooling and heating can be greatly reduced.Furthermore, by opening the first and second on-off valves during heating, In addition to further reducing the heating capacity, it is possible to reduce the input during cooling due to the above-mentioned factors, and the change in temperature is smaller compared to the conventional method of controlling the air conditioning temperature, especially during cooling, by intermittent operation of the compressor. ,
It has various advantages such as an improved feeling of air conditioning, and there is no need to reduce the heat exchange capacity of the heat source side heat exchanger when the heating load is heavy.

[Brief explanation of the drawing]

Fig. 1 is a diagram of a refrigeration cycle equipped with an overload control device according to an embodiment of the present invention, Fig. 2 is a sectional view of a rotary compressor that constitutes the refrigeration cycle, and Fig. 3 is another embodiment of the present invention. It is a sectional view of the rotary compressor in an example. 1... Rotary compressor, 5... Cylinder, End... Zeston, 13... Intermediate discharge hole, 15
......Intermediate discharge valve, 16...Intermediate discharge passage, 19...Four-way switching valve, 20...Heat source side heat exchanger, 21... ...Aperture device, 22...
... User side heat exchanger, 24 ... Flow rate restriction device,
25... Bypass path, 26... First on-off valve, 27... Suction bypass path, 28...
...Second on-off valve.

Claims (1)

[Scope of utility model registration request] A refrigeration cycle is composed of a rotary compressor, a four-way switching valve, a user side heat exchanger, a heat source side heat exchanger, and a pressure reducing device.
The rotary compressor is provided with a cylinder and a piston, and an intermediate discharge hole is provided in the compression space of the cylinder and opens halfway through the compression stroke, and the intermediate discharge port communicates with the outside of the rotary compressor via an intermediate discharge valve. An intermediate discharge passage is provided, and the refrigeration cycle is further provided with a bypass passage whose one end is connected between the utilization side heat exchanger and the four-way switching valve and the other end is connected to the intermediate discharge passage, A refrigeration cycle in which a first on-off valve is provided in the bypass path, and a suction bypass path is connected from between the first on-off valve and the intermediate discharge valve to the suction path side of the compressor via a second on-off valve. overload control device.