JPH01123965A - Air conditioner - Google Patents

Abstract

PURPOSE: To decrease a defrost time and prevent defrosted water from being frozen again by providing a first bypass circuit having a flow rate control valve between the discharge gas piping of a compressor and the inlet piping of an accumulator and a second bypass circuit having a solenoid valve for bypassing a second throttle device. CONSTITUTION: In a defrosting operation, a part of high temperature and high pressure gas refrigerant discharged from a compressor 1 enters an accumulator 11 through a first bypass circuit 20 from a discharge piping 2 and the rest thereof enters an indoor side heat exchanger 8 through a four-way selector valve 3 switched to a heating side and passes bypass circuit 63 for bypassing a second throttle device 6 through the first check valve 71 of a first throttling device 7. At this time, a solenoid valve 64 provided in the bypass circuit 63 is closed. Then, frost adhering on the surface of an outdoor side heat exchanger 4 is melted by the high temperature gas refrigerant and the refrigerant is condensed and liquefied and enters the accumulator 11 through the four-way selector valve 3. The first bypass circuit 20 detects the shell temperature of the compressor 1 or the temperature of the discharge piping 2 to close a flow rate control valve 21, so that switching loss is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an air conditioner, and particularly to refrigerant control during defrost operation.

[Conventional technology]

Figure 2 shows the refrigerant cycle of a conventional air conditioning system. outer fan, 6 is a second throttle device, 61 is a second check valve that passes 79 the second capillary tube 62, 7 is a first throttle device, 71 is the first capillary tube 7;
2 is a first check valve that prevents a pinch error; 8 is an indoor heat exchanger; 9 is an indoor fan that blows air to this heat exchanger 8;
is an accumulator.

Next, the operation will be explained. First, during cooling operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor 8!1 is energized by the four-way switching valve 3 as shown by the thick solid arrow, and is blown by the outdoor fan 5 in the outdoor heat exchanger 4. It exchanges heat with outdoor air, and the refrigerant condenses and liquefies. Thereafter, the refrigerant passes through the second check valve 61t'' of the second expansion device 6 and is depressurized (by the first capillary tube 72 of the first expansion device 7) to become a low-temperature, low-pressure liquid refrigerant. The refrigerant enters the indoor heat exchanger 8 and cools the indoor air by exchanging heat with the indoor air blown by the indoor fan 91C.The refrigerant evaporates and becomes gas, passes through the four-way switching valve 3 and the accumulator 11, and then is sent to the compressor. 1, and the above operation is repeated.

Next, in the case of heating operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is energized by the four-way switching valve 3, which is switched to the heating side, as shown by the thin solid line, and is then input into the indoor heat exchanger 8. ,
The refrigerant is condensed and liquefied by exchanging heat with the indoor air blown by the indoor fan 9 to heat the air. Then, the refrigerant is energized through the first check valve 71 of the first expansion device 7 and is depressurized by the second capillary tube 62 of the second expansion device 6, becoming a low-temperature, low-pressure liquid refrigerant. After that, the liquid refrigerant enters the outdoor heat exchanger 4 and exchanges heat with the outdoor air that is blown by the outdoor fan 5, collects heat from the outdoor air and cools the air, and the refrigerant evaporates and gases. The switching valve 3 and the accumulator 11 are returned to the energized compressor 1, and the above operations are repeated thereafter. Note that if the above-mentioned operation is continued, frost will form on the outdoor heat exchanger 4, for example, if the outdoor air temperature is low. When this amount of frost increases, heat exchange decreases and the amount of heat extracted from the outdoor air decreases, resulting in a significant decrease in the heating capacity of the air conditioner, making defrosting necessary.

Next, defrost operation will be explained. The high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is energized through the four-way switching valve 3, which is switched from the heating side to the cooling side, as shown by the broken line, and enters the outdoor heat exchanger 4. At this point, the outdoor fan 5 is stopped. Then, the frost forming on the surface of the outdoor heat exchanger 4 is melted by the high-temperature gas refrigerant, the refrigerant is condensed and liquefied, and the second reverse valve 61 of the second throttle device 6 is energized, and the first Squeezing device 7
The pressure is reduced in the first capillary tube 71 of the
The low-pressure liquid refrigerant enters the indoor heat exchanger 8. At this point, the indoor fan 9 normally operates in a light breeze mode or is stopped. When the breeze operation is performed, the low-temperature, low-pressure liquid refrigerant and indoor air exchange heat, the air is cooled, the refrigerant evaporates, and then returns to the compressor 1 via the four-way switching valve 3 and the accumulator 11. In this case, cold air is blown indoors, which significantly reduces the air conditioning effect. Furthermore, when the indoor fan 9 is stopped, the low-temperature, low-pressure liquid refrigerant cannot collect heat and enters the accumulator 11 as a liquid and returns to the compressor 1. This may lead to malfunction. Furthermore, regarding the outdoor heat exchanger 4, when the outside temperature is low, since the heating operation starts immediately after the defrost operation ends, the defrost water may not be able to fall sufficiently from the surface of the outdoor heat exchanger 4, and it may freeze again. there were.

[Problem that the invention seeks to solve]

Since conventional air conditioners are configured as described above, when defrosting during heating operation, cold air is supplied into the room, and if the cold air is stopped, there is a possibility of liquid compression problems in the compressor. Furthermore, during defrosting, since the high pressure was low, the low pressure was also low, making it impossible to fully utilize the compression function, and the defrosting time took a long time. Furthermore, during the heating operation, the four-way switching valve 3't is switched to the cooling side to perform the defrost operation, resulting in switching heat loss. Further, when the outside temperature is low, the defrost water does not completely fall off the surface of the outdoor heat exchanger 4 and enters the heating operation, which may cause it to refreeze.

This invention was made to solve the above-mentioned problems, and aims to provide an air conditioner that can shorten the defrost time and at the same time drain the defrost water. purpose.

[Means for solving problems]

The air conditioner according to the present invention provides a first bypass n path equipped with a flow rate control valve between the discharge gas piping of the compressor and the accumulator inlet piping, and a second solenoid valve that completely bypasses the throttle valve. A second bypass circuit is provided.

[Function] In this invention, the first and second bypass circuits are opened during defrost operation, the four-way switching valve remains on the heating side, and the indoor side heat exchanger and the guide side heat exchanger function as a total condenser. However, by defrosting the outdoor heat exchanger and bypassing the gas refrigerant discharged from the compressor to the low pressure side, the low pressure can be increased and the low pressure liquid refrigerant can be used as a heat collection source. Also, before the defrost is finished, the indoor/outdoor fan is operated to drain the outdoor heat exchanger and then the heating operation is started.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows a refrigerant cycle of an air conditioner according to the present invention. In the figure, 1 is a compressor, 2 is a discharge pipe of this compressor, 3 is a four-way switching valve, 4 is an outdoor heat exchanger, and 5 is an outdoor heat exchanger. 6 is a second throttle device; 61 is a second check valve that completely bypasses the second capillary tube 62; 63 is a second check valve that bypasses the second throttle device 6; 64 is a solenoid valve provided with a second bypass circuit 631C. 7 is a first throttle device, 71 is a first check valve that bypasses the first capillary tube 72, 8 is an indoor heat exchanger, 9 is an indoor fan that blows air to the indoor heat exchanger 8; 10 is an inlet pipe of the accumulator 11, 20 is a first bypass circuit connecting the discharge pipe 2 and the inlet pipe 10 of the accumulator 11, 21 is a flow control valve provided in the first bypass circuit 20, 30 is a controller that detects the entire shell temperature or discharge gas temperature of the compressor 1 and outputs an opening/closing signal to the flow rate control valve 21.

Next, the operation will be explained. First, during cooling operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 is energized by the four-way switching valve 3 as shown by the thick solid line arrow, and the outdoor fan 5 blows the air in the outdoor heat exchanger 4. The refrigerant condenses and liquefies by exchanging heat with the outdoor air. Thereafter, the refrigerant passes through the second check valve 61 of the second expansion device 6, is depressurized by the first capillary tube 72 of the first expansion device 7, and becomes a low-temperature, low-pressure liquid refrigerant. The liquid refrigerant then enters the indoor heat exchanger 8 and exchanges heat with the indoor air blown by the indoor fan 9 to cool the indoor air, and the refrigerant is evaporated and gasified to the four-way switching valve 3 and the accumulator. 11 and then returned to the compressor 1, whereupon the above operation is repeated.

Next, in the case of heating operation, the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way switching valve 3, which is switched to the heating side, and enters the indoor heat exchanger 8, as shown by the thin solid line. C,
The refrigerant is condensed and liquefied by exchanging heat with the indoor air blown by the indoor fan 9 to heat the air. Then, the refrigerant is energized through the first check valve 71 of the first expansion device 7 and depressurized by the second capillary tube 62 of the second expansion device 6, becoming a low-temperature, low-pressure liquid refrigerant. After that, the liquid refrigerant enters the outdoor heat exchanger 4 and exchanges heat with the outdoor air blown by the outdoor fan 5, collects heat from the outdoor air and cools the air, and the refrigerant evaporates and gases. The switching valve 3 and the accumulator 11 are returned to the energized compressor 1, and the above operations are then repeated. Note that if the above-mentioned operation is continued, frost will form on the outdoor heat exchanger 4, for example, if the outdoor air temperature is low. When this amount of frost increases, heat exchange decreases and the amount of heat extracted from the outdoor air decreases, resulting in a significant decrease in the heating capacity of the air conditioner, making defrosting necessary.

Next, defrost operation will be explained. A portion of the high-temperature, high-pressure gas refrigerant discharged from the compressor 1 enters the accumulator 11 from the discharge pipe 2 (throughout the first bypass circuit 20), as shown by the broken line. In addition, the four-way switching valve 3, which has been switched to the heating side, is energized and enters the indoor heat exchanger 8. At this time, the indoor fan 9 is stopped, and the first check valve 71 of the first throttle device 7 is energized as it is through the second bypass circuit 63 that bypasses the second throttle device 6 .

At this time, the solenoid valve 6 provided in the second bypass circuit 63
4 is open circuit. The hot gas refrigerant then enters the outdoor heat exchanger 4. At this time, the outdoor fan 5 is stopped.

In this way, the frost formed on the surface of the outdoor heat exchanger 4 is melted by the high-temperature gas refrigerant, and the refrigerant is condensed and liquefied and enters the four-way switching valve 3 all-through shaker 11. Here, it is mixed with the high-temperature gas refrigerant that has entered from the first bypass circuit 20, extracts heat from the high-temperature gas refrigerant, evaporates into gas, and returns to the compressor 1. In this case, the first bypass circuit 20 detects the shell temperature of the compressor 1 or the temperature of the discharge pipe 2. For example, when the shell temperature is 80°C or higher or the temperature of the discharge pipe 2 is 130°C or higher, the flow control valve 21 I am trying to make a closed circuit. Therefore, during defrosting, the four-way switching valve 3 can enter the defrosting operation without switching from the heating side to the cooling side, so there is no switching loss. Furthermore, since the high-temperature gas refrigerant passes through the entire interior of the indoor heat exchanger 8, there is no cold air inside the room. Furthermore, since the high-temperature gas refrigerant is bypassed to the low-pressure side, the low-pressure pressure increases, the capacity of the compressor 1 can be fully demonstrated, and the defrost time can be shortened. Also,
Since the indoor fan 9 and the outdoor fan 5 are operated immediately before the end of defrosting, an abnormal rise in high pressure can be prevented before the end of defrosting, and the defrost water in the outdoor heat exchanger 4 can be drained.

〔Effect of the invention〕

As explained above, according to the present invention, the first bypass circuit equipped with the flow control valve is installed between the discharge gas pipe of the compressor and the accumulator inlet pipe, and the second throttle device is connected to the pipe bypass circuit. A second bypass circuit equipped with a solenoid valve is provided, which prevents switching loss of the four-way switching valve, prevents cold air from blowing into the room, and reduces compression function power due to rise in low pressure. By improving this, it is possible to shorten the bufrost time. Furthermore, since the water can be drained immediately before the end of the defrost operation, re-freezing of the defrost water can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a refrigerant cycle diagram of an air conditioner according to an embodiment of the present invention, and FIG. 2 is a refrigerant cycle diagram of a conventional air conditioner. DESCRIPTION OF SYMBOLS 1...Compressor, 2...Discharge piping, 3...Four-way switching valve, 4...Outdoor side heat exchanger, 5...Outdoor side fan,
6... Second diaphragm device, 7... First diaphragm device, 8
...Indoor heat exchanger, 9...Indoor fan, 10.
... Accumulator inlet piping, 11... Accumulator, 20... First pinosu circuit, 21...
Flow control valve, 30...controller, 63...second
Bypass circuit, 64... solenoid valve. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] The compressor, the four-way switching valve, the indoor heat exchanger, the first and second throttling devices, the outdoor heat exchanger, and the accumulator are connected to the refrigerant pipes in this order, and the first pipe bypasses the compressor discharge pipe and the accumulator inlet pipe. bypass circuit,
This bypass circuit is equipped with a flow control valve that controls the refrigerant flow rate based on a temperature signal of the shell temperature of the compressor or a pipe temperature signal of the compressor discharge pipe, and a controller that adjusts the opening degree of the flow rate control valve based on the above signal. An air conditioner comprising: a second bypass circuit that bypasses the throttle device; and a solenoid valve in the bypass circuit.