JPS6038562A - Air conditioner - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an air conditioner, and particularly relates to a compressor having a capacity control mechanism, a utilization side heat exchanger, an air side heat exchanger, an expansion valve,
This invention relates to an air conditioner using an air source heat pump system, in which a four-way valve and an accumulator are successively connected by refrigerant piping.

[Prior art]

Air conditioners using an air source heat pump system use an air-side heat exchanger to absorb thermal energy from outdoor air and release it indoors, and are rapidly becoming popular due to their high thermal efficiency. .

FIG. 1 is a block diagram showing an embodiment of an air conditioner using an air source heat pump system that has been commonly used in the past. In the figure, 1 is a compressor that compresses refrigerant; 2 is a compressor that compresses refrigerant;
is a discharge pipe connected to the discharge port of the compressor 1, 3 is a four-way valve connected to this discharge pipe 2, and 4 is a user-side heat exchanger, which is connected to the compressor 1 via the four-way valve 3. There are many. 5 is a four-way switching valve whose one end is connected to the utilization side heat exchanger 4, and 6 is an air-side heat exchanger connected between the four-way switching valve 5 and the four-way valve 3. 7 is an accumulator inlet pipe connecting between the accumulator 8 and the four-way valve 3; 9 is an accumulator 8;
This is the accumulator outlet piping that connects the compressor 1 and the compressor 1.

Note that dotted line arrows in the figure indicate the flow of refrigerant during heating operation, and dotted line arrows indicate the flow of refrigerant during cooling operation.

In the air conditioner configured in this way, first, during heating operation, the refrigerant is compressed to a high temperature and high pressure in the compressor 1.
Discharge pipe 2. By being supplied to the user-side heat exchanger 4 via the four-way valve 3, the heat is absorbed by the user-side fluid (hot water or hot air) and condenses and liquefies. Then, the refrigerant that has passed through the user-side heat exchanger 4 is supplied to the air-side heat exchanger 6 via the four-way switching valve 5 in a low-temperature, low-pressure, easily evaporated state by a pressure reducing device. In the air side heat exchanger 6, heat is absorbed from the air (outside air) and evaporated, and this evaporated refrigerant is passed through the four-way valve 3. Accumulator inlet piping7. Accumulator8. Compressor 1 via accumulator outlet piping 9
form a cycle by returning to . In this way, the user-side fluid is heated and provided for heating.

On the other hand, the flow of refrigerant during cooling operation is such that the user-side heat exchanger 4 acts as an evaporator, and the user-side fluid (chilled water or cold air)
Cooling is performed by

However, in the air conditioner using the air source heat pump method described above, the user side fluid temperature is high during heating operation.
In addition, when the outside air temperature is low, the high pressure side is high and the low pressure side is low, which causes the discharge gas temperature to become abnormally high, resulting in decomposition of the refrigerant and changes in the lubricating oil, resulting in harsh operation for the compressor. I have a problem.

[Summary of the invention]

Therefore, the electric conditioner according to the present invention has been devised to eliminate the above-mentioned conventional deficiencies, and by providing a hot gas bypass circuit between the output side of the compressor and the accumulator. The purpose of the present invention is to provide an air conditioner using an air heat source heat pump system that can optimize the discharge gas temperature even when the side fluid temperature is high (and the outside air temperature is low).

[Embodiments of the invention]

FIG. 2 is a block diagram showing an embodiment of the air conditioner according to the present invention, and the same parts as in FIG. 1 are denoted by the same symbols and detailed explanation thereof will be omitted.

In the figure, 13 is a stop valve whose one end is connected to the discharge pipe 2, 14 is an electromagnetic on-off valve whose one end is connected to the outlet side of the stop valve 5, and 15 is a connection between the electromagnetic on-off valve 15 and the accumulator 8. A second capillary reach tube 16 is connected between the outlet side of the stop valve 13 and the accumulator 8.

In the air conditioner configured in this way, during heating operation, the higher the temperature of the fluid on the user side and the lower the outside air temperature, the higher the high pressure side becomes and the lower the low pressure side becomes, and the discharge gas temperature becomes higher. In this state, the inside of the discharge pipe 2 is under high pressure and the temperature of the discharged gas is high, while the inside of the inlet pipe 7 of the accumulator 8 is under low pressure and at a low temperature.

When the electromagnetic on-off valve 14 is opened during full operation of the compressor 1, the differential pressure between the pressure in the discharge pipe and the pressure in the accumulator 80 input pipe 7 is increased by the stop valve 13. Solenoid on-off valve 14. The amount of refrigerant that is equal to the fluid resistance of the refrigerant flowing through the first capillary reach tube 15 and the second capillary reach tube 16 flows from the discharge pipe to the accumulator inlet pipe 7.

On the other hand, since the pressure reducing device 10 is equipped with the temperature sensing cylinder 11 at the outlet pipe 9 of the accumulator, the temperature at this position is controlled to be constant.

As a result, the temperature of the mixture of the refrigerant gas binoxed from the discharge pipe 2 and the refrigerant that evaporates from the air side heat exchanger 6 and flows into the accumulator inlet pipe 7 via the four-way valve 3 is measured. It is detected by the cylinder 11. Therefore, if the amount of nitrogen from the bypass circuit increases, the state of the refrigerant at the outlet side of the air-side heat exchanger 6, which serves as the evaporator, will be desuperheated, and the saturated refrigerant gas and saturated refrigerant liquid will be mixed. A two-phase state occurs due to the mixed state.In this case, as is generally known, in the evaporator, the refrigerant side heat transfer coefficient shows the highest value when the refrigerant is in the two-phase state.Therefore, the air-side heat exchanger Since the state of the refrigerant on the outlet side of 6 is in the phase range, the heat exchange performance in the air side heat exchanger 6 is greatly improved, and as a result, the pressure on the low pressure side increases.

On the other hand, since a part of the discharged gas discharged from the compressor 1 is bypassed via the bypass circuit as in the case described above, the amount of refrigerant flowing to the user-side heat exchanger 4 decreases.
As a result, the pressure on the high pressure side decreases. In addition, the amount of refrigerant bypassed by bypass piping is large.
In other words, when the high pressure side is high and the low pressure side is low (state where the fluid temperature on the user side is high and the outside air temperature is low), the state of the refrigerant flowing into the accumulator, that is, the bypassed refrigerant and the outlet of the air side heat exchanger 6. The mixture with the refrigerant becomes a two-phase state. When it flows into the accumulator 8 in this two-phase state, gas and liquid are separated by the action of the accumulator 280, so that only the gas refrigerant flows from the accumulator outlet pipe 9. The separated liquid refrigerant will accumulate at the bottom of the accumulator 8, but this liquid refrigerant will pass through the oil return pipe 12 and be discharged from the outlet pipe 9 of the accumulator 8.As a result, Compressor 1
The refrigerant sucked into the refrigerant is a refrigerant with almost no superheat. Here, the first capillary tube 15. The length of the second capillary reach tube 16 needs to be determined by testing so as to provide an appropriate amount of bypass.

In this way, by providing a bypass circuit and optimizing its bypass amount, the temperature of the discharged gas can be adjusted to an appropriate value by reducing the pressure on the high pressure side, increasing the pressure on the low pressure side, and returning the liquid appropriately to the accumulator 8. It can be kept at

Furthermore, when the compressor 1 is operated under capacity control, the electromagnetic on-off valve 14 is closed to cut off the refrigerant flowing to the first capillary reach tube 15 and allow it to flow only to the second capillary reach tube 16. By doing this, the amount of bypass can be reduced, and accordingly, an appropriate amount of bypass can be maintained even during capacity control operation. If such measures are not taken, the amount of bypass becomes excessive and a large amount of liquid refrigerant accumulates in the accumulator, causing liquid back-up operation and damage to the compressor.

The above is the case during heating operation, but during cooling operation, the pressure difference between the high pressure side and the low pressure side is smaller than during heating, and the discharge gas temperature does not rise much. Therefore, a large amount of bypass is not required. Therefore, during cooling operation, the temperature of the discharged gas can be lowered somewhat by closing the electromagnetic on-off valve 14 and reducing the amount of bypass using only the second capillary reach tube.

In the above embodiment, a case has been described in which one end of the bypass pipe is connected to the inlet pipe 7 of the accumulator 8, but it goes without saying that it may be directly connected to the accumulator 8.

[Effect of idea]

As explained above, the air conditioner according to this invention includes a series body consisting of a solenoid valve and a first capillary between the discharge side of the compressor and the acchierator, and a second capillary connected in parallel to the first capillary. The solenoid valve is opened to increase the amount of bypass during full compressor operation during heating, and the amount of bypass is reduced by closing the solenoid valve during capacity control operation, and furthermore, during cooling operation, the solenoid valve is closed to reduce the amount of bypass. By closing the solenoid valve and reducing the amount, the discharge gas temperature is maintained at an appropriate value.
In particular, it has an excellent effect of allowing highly reliable operation even under severe conditions such as low outside temperature during heating and high temperature of the fluid on the user side.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an air conditioner using a conventional air source heat pump system, and FIG. 2 is a block diagram showing an embodiment of an air conditioner according to the present invention. 1...Compressor, 2...Discharge piping, 3...Four-way valve,
4... User-side heat exchanger, 5... Four-way switching valve, 6...
・Air side heat exchanger, 7" Accumulator inlet piping, 8
...Accumulator, 9...Accumulator outlet piping, 10...Pressure reducing device, 11...Temperature sensing tube, 12...
・Oil return piping, 13° stop valve, 14°...electromagnetic shut-off valve,
15...1st capillary reach tube, 16...2nd
Capillar Reach Youtube. In the drawings, identical or half-phase parts are indicated using the same symbols. Agent Masuo Oiwa (2 others) Spear 11 Otsuo 2 Eyes: Knee---4

Claims (1)

[Claims] (1) In an air-source heat pump type air conditioner configured by sequentially connecting a compressor with a capacity control mechanism, a four-way valve, a user-side heat exchanger, an air-side heat exchanger, and an accumulator, A series body of a stop valve, an electromagnetic on-off valve, and a first capillary reach tube connected between the discharge piping of the compressor and the inlet side piping of the accumulator, and in parallel with the electromagnetic on-off valve and the first capillary. A hot gas bypass circuit is established with the connected second capillary, and the solenoid valve is opened during heating operation and full compressor operation, and closed during capacity control operation, and the solenoid valve is closed during cooling operation regardless of the operating state of the compressor. An air conditioner characterized by closing an on-off valve. (21) The air conditioner according to claim 1, wherein one end of the hot gas bypass circuit is directly connected to the accumulator.