JPS6251383B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an air conditioner using a capacity control compressor.
The objective is to provide an efficient air conditioner that configures an appropriate refrigeration cycle and obtains cooling capacity according to the load.

For example, when using a pole converter compressor to change the refrigerant discharge amount according to the load, when using a 4-pole compressor, the compressor rotational speed is halved compared to when using 2 poles, which reduces the refrigerant discharge amount by half, resulting in a lower load. Accordingly, efficient operation can be performed.

However, in this case, at the time of four poles, the discharge pressure decreases, so the degree of supercooling is small at the inlet of the throttling resistor, the cooling capacity decreases, and the growth coefficient decreases. Furthermore, the appropriate amount of refrigerant required in the refrigeration cycle is different between two-pole operation and four-pole operation, which have different cooling loads, so simply using a pole converter compressor does not necessarily result in efficient operation. It wasn't something.

Furthermore, during low-load four-pole operation, the refrigerant cannot be completely evaporated in the evaporator, causing a so-called liquid back phenomenon in which the refrigerant returns to the compressor. Furthermore, when the cooling load is even smaller, the compressor repeatedly starts and stops, but the compressor has the disadvantage that when starting the compressor, the compressor compresses the liquid refrigerant that has remained in the evaporator. In particular, under such operating conditions, the degree of superheating of the refrigerant sucked into the compressor is small and the refrigerant tends to be compressed wet, which has been pointed out as a significant drawback.

Furthermore, as a method for increasing the operating efficiency of an air conditioner, a method is known in which the degree of subcooling of the refrigerant at the throttle resistor inlet is increased by exchanging heat between the refrigerant pipe at the throttle resistor inlet and the compressor suction pipe.

However, when this method is applied to the refrigerant circuit of a pole conversion compressor, the degree of subcooling and superheating can be large in the case of four-pole operation, but in the case of two-pole operation, the degree of subcooling and superheating are originally large, and the compressor Since the discharge temperature is high, the degree of superheating further increases, resulting in a disadvantage that the discharge refrigerant temperature becomes too high.

The present invention has been made in view of the above points, and will be explained in detail below with reference to the drawings. FIG. 1 shows a refrigerant circuit equipped with a pole change compressor according to the present invention. Reference numeral 1 is a pole conversion compressor, 2 is a condenser, 3 is a first pressure reducer, and 4 is an evaporator, which constitute a refrigerant circuit. Reference numeral 7 denotes a first electromagnetic on-off valve that is provided between the first pressure reducer 3 and the evaporator 4 and opens when the compressor 1 is in bipolar operation, and 5 is a second pressure reduction valve that is provided in parallel with this on-off valve 7. 8 is an accumulator, which is branched from the discharge circuit 13 which immediately enters the condenser 2 from the compressor 1, is provided with a throttling resistor 9 in the middle, passes through the accumulator 8, and joins the discharge circuit 13. The circuit 14 is formed in a communicating state. Reference numeral 10 denotes a branch section provided in the middle of the evaporator 4, which is provided with a two-way electromagnetic on-off valve 11 in the middle, and which leads to a heat transfer tube 12 that meandered inside the accumulator 8, and which connects the compressor 1. The low pressure refrigerant pipe 15 connected to the suction pipe 16 is connected in a branched manner. Reference numeral 17 denotes an evaporator side suction pipe, which is connected to the suction pipe 16 described above.

Next, the operation of the present invention will be explained. Compressor 1
The refrigerant discharged from the refrigerant immediately enters the discharge circuit 13 which enters the condenser 2 and the accumulator 8, passes through the throttle resistor 9, and enters the branch circuit 14 which enters the condenser 2.
It is branched into. Further, a low pressure refrigerant pipe 15 is connected to a branch part 10 provided in the middle of the evaporator 4.
The refrigerant gas No. 5 passes through the two-way electromagnetic on-off valve 11, enters the aforementioned accumulator, exchanges heat with the discharged gas refrigerant through the heat transfer tube 12, joins the suction pipe 16, and is sucked into the compressor 1. A parallel circuit is formed of a refrigerant circuit in which the refrigerant is drawn into the compressor 1 from the evaporator-side suction pipe 17 through the suction pipe 16.

When the normal cooling load is large, that is, during two-pole operation, the two-way electromagnetic on-off valve 11 is closed.
The refrigerant evaporated in the evaporator 4 does not pass through the heat transfer tube 12 in the accumulator 8 and is directly sucked into the compressor 1 from the evaporator side suction pipe 17, so that the refrigerant discharged from the compressor 1 One side always flows into the accumulator 8, but since the low-pressure and low-temperature refrigerant from the evaporator 4 does not flow in, there is no heat exchange between the discharged refrigerant and the suctioned refrigerant, and the discharged refrigerant does not liquefy, resulting in the same refrigeration as before. Configure the cycle.

When the cooling load is small, that is, during four-pole operation, the compressor rotation speed is low, and therefore the amount of refrigerant circulating is small, so it is necessary to increase the throttling resistance of the refrigerant, and the electromagnetic on-off valve 7 is closed. At the same time, the two-way electromagnetic on-off valve 11 is opened to allow the low-pressure, low-temperature refrigerant in the evaporator 4 to flow into the heat transfer tubes 12 in the accumulator 8 . Therefore, one of the branched high-temperature, high-pressure refrigerants discharged from the compressor is liquefied and stored in the accumulator 8 by the heat transfer tube 12 . Since the outlet pipe of the accumulator 8 on the high pressure side is provided with a throttle resistor 9, the refrigerant flow rate in this pipe is much smaller than that in the other discharge pipe 13, which greatly changes the superheat of the suction refrigerant. It is possible to maintain the same level of super heat as during two-pole operation without any problems.

In this way, liquid refrigerant accumulates in the accumulator when changing the number of poles, and the amount of refrigerant circulated during the refrigeration cycle can be adjusted. In other words, during 4-pole operation, refrigerant accumulates in the accumulator 8, so the amount of refrigerant distributed in the condenser 2, evaporator 4, and other piping is smaller than during 2-pole operation, resulting in more efficient operation according to the load. can be done.

Therefore, according to the present invention, when the cooling load is small, the refrigerant that was conventionally compressed due to dampness can be reduced to a super high temperature by reducing the amount of circulating refrigerant and by heat exchange of the suction refrigerant in the accumulator. The above-mentioned drawbacks can be solved by obtaining the necessary amount of heat.
At the same time, by being able to operate with an appropriate amount of refrigerant commensurate with the load, the coefficient of performance of the cycle improves.

In addition, the refrigerant that accumulates in the evaporator when the compressor is started and stopped flows into the compressor when restarted, which was a large startup load.In the case of the present invention, the indoor load is small when the compressor is stopped. Therefore, since 4-pole operation is performed and refrigerant is accumulated in the accumulator, there is no sudden inflow of refrigerant containing liquid refrigerant into the compressor, and it functions as a protection device for the compressor. , the load at startup can be reduced.

In addition, while the compressor is stopped, the refrigerant liquid continues to flow to the low pressure side and is condensed again in the evaporator, warming the evaporator and reducing the refrigeration effect, thereby solving the above-mentioned liquid compression problem. Since the accumulator is located on the discharge side of the compressor, the inflow of refrigerant into the low pressure side when the compressor is stopped can be suppressed to a very small amount, and losses when the compressor is restarted can be minimized.

The effects of the present invention have been explained above using a pole number changing compressor as an example, but the present invention has similar effects not only on pole number changing, but also on compressors that change the output of the compressor in stages. be.

[Brief explanation of the drawing]

The figure is a diagram showing a refrigerant circuit of an air conditioner according to the present invention. In the figure, 7 is an electromagnetic on-off valve, 8 is an accumulator, 9 is a throttle resistor, 10 is a branch part, and 12 is a heat exchanger tube.

Claims (1)

[Claims] 1. In an air conditioner comprising a variable capacity compressor capable of switching the compressor motor between two poles and four poles, a condenser, a first pressure reducer, a second pressure reducer, and an evaporator connected in sequence. A circuit is constructed in which the refrigerant discharged from the compressor is branched in parallel, one is led to an accumulator, and after passing through the accumulator, it joins with the other refrigerant discharged and enters the condenser. A refrigerant circuit is branched into the pipe, which passes through the accumulator via a two-way electromagnetic on-off valve and a heat transfer tube, joins the evaporator suction pipe, and is sucked into the compressor, and a solenoid on-off valve is connected in parallel to the second pressure reducer. When the compressor is operating at high output, the solenoid on-off valve is opened and the two-way solenoid on-off valve is closed.When the compressor is operating at low output, the solenoid on-off valve is closed. An air conditioner characterized in that a two-way electromagnetic on-off valve is opened, and the refrigerant discharged from the compressor and the low-pressure refrigerant passing through the two-way electromagnetic on-off valve are subjected to heat exchange in an accumulator. 2. The air conditioner according to claim 1, characterized in that the accumulator outlet pipe on the discharge side of the compressor is provided with a throttling resistance.