JPH0132431B2 - - Google Patents

Description

Detailed Description of the Invention The present invention connects a plurality of indoor units to one outdoor unit, and uses a four-way valve provided in the outdoor unit to control the flow of refrigerant between cooling and heating. The present invention relates to a heat pump type air conditioner/heater that performs air conditioning and heating by switching to the air conditioner, and aims to increase heating capacity during heating and reduce overload when a compressor is overloaded.

In conventional multi-type heat pump air conditioners, refrigerant control is performed as shown in FIG. That is, in FIG. 1, 51 is an outdoor unit, 52 is a rotary compressor, 53 is a four-way valve that switches the flow of refrigerant during cooling and heating, and 54 is an outdoor heat exchanger that serves as a condenser during cooling and an evaporator during heating. vessel, 5
5a, 55b are first capillary tubes, 56
a, 56b are liquid side electromagnetic valves, 57a, 57b are three-way valves connected to indoor units 58a, 58b and have a service valve, 59a, 59b are second capillary tubes, 60a, 60b are cooling evaporators. , indoor heat exchanger that serves as a condenser during heating, 61a,
61b is a three-way valve, 62a and 62b are gas-side solenoid valves, 63a and 63b are check valves through which refrigerant bypasses gas-side solenoid valves 62a and 62b during cooling and are closed during heating, and 64 is an accumulator. , 65
a and 65b are check valves that always send a small amount of refrigerant to the rotary compressor 52 through the injection exit capillary tube 66 during both cooling and heating;
67, when an abnormally high pressure occurs during either cooling or heating, the opening degree is adjusted according to the high pressure, and the refrigerant is returned to the suction pipe 68 side to lower the temperature, thereby reducing the abnormally high pressure of the compressor 52. 69 is a discharge pipe, and 70a and 70b are capillary tubes.

Conventionally, such a refrigerant circuit is configured, and if a small amount of gas-liquid mixed refrigerant flows into the check valves 65a and 65b during heating, the refrigerant for the injection exit (due to the resistance of the capillary tube 66 for the injection exit) The refrigerant is returned to the compressor 52 from the capillary tube 66 of the indoor unit 58a, 58b.
It is condensed in the indoor heat exchangers 60a and 60b, and the pressure is reduced in the capillary tubes 59a and 59b, and it returns as a gas-liquid mixed refrigerant, but the gas-liquid mixture is mainly liquid refrigerant that is compressed during compression in the cylinder in the compressor. The disadvantage is that the heating capacity decreases because the air is injected into the gas to alleviate the temperature rise. Similarly, when the indoor temperature rises during heating, the compressor 52 becomes overloaded, and the high-pressure pressure regulating valve 67 causes the suction pipe to The refrigerant is returned to the 68 side, but since the refrigerant is a gas-liquid mixture, a sufficient amount of refrigerant does not return to the suction pipe side, resulting in a large burden on the compressor during overload. It had

The present invention solves the above-mentioned conventional drawbacks, and an embodiment thereof will be described below based on FIG. 2.
In Fig. 2, 1 is an outdoor unit, 2 is a rotary compressor, 3 is a four-way valve for switching the flow of refrigerant during cooling and heating, and 4 is a condenser during cooling and an evaporator during heating. 5 is a first capillary tube for cooling, 6 is an outdoor heat exchanger that acts as a
a and 6b are check valves, 7a and 7b are liquid-side solenoid valves that are opened and closed by operation of the indoor unit, 8a and 8b are three-way valves provided in the outdoor unit 1, and 9a and 9b are provided on the indoor unit 10a side. Two-way valve, 10
b is another indoor unit. 11a and 11b are second capillary tubes 12a and 11b for cooling provided in the indoor units 10a and 10b, respectively;
12b is a check valve provided to bypass the second capillary tubes 11a and 11b so that the condensed refrigerant flows to the outdoor unit 1 side during heating and not during cooling; 13a and 13b are condensers during heating; indoor heat exchanger acting as an evaporator, 14a,1
4b is a two-way valve, 15a and 15b are outdoor unit 1
The three-way valves 16a and 16b provided on the side plates of the gas side solenoid valves 17a and 16b are opened for heating and closed for cooling, respectively, by the operation of the indoor units 10a and 10b.
17b is a check valve provided so that gas refrigerant flows during cooling, does not flow during heating, and bypasses gas-side solenoid valves 16a and 16b during cooling; 18 is an accumulator that vaporizes liquid refrigerant; 19 20 is a suction pipe, 21 is a high-pressure pressure regulating valve, and when the refrigerant discharged from the compressor 2 becomes abnormally high during operation, the pressure in the pipe 22 increases, A part of the refrigerant is liquefied in a heat exchange part 23 for a high-pressure pressure regulating valve provided in a part of the outdoor heat exchanger 4, and the liquefied refrigerant is passed through a high-pressure pressure regulating valve whose opening degree is adjusted according to the pressure. By flowing through the refrigerant 21 and bypassing the suction pipe 20 and returning a portion of the liquid refrigerant, the amount of refrigerant passing through the high-pressure pressure regulating valve 21 is increased and the load on the compressor is reduced. 24 is a heating solenoid valve that opens during heating and closes during cooling; 25a, 2
5b is a heating pipe through which refrigerant flows only during heating; 26
a, 26b are check valves through which refrigerant flows only during heating; 2
7a and 27b are first capillary tubes for heating, and 28 is a gas-liquid mixed refrigerant always stored at an intermediate pressure (after passing through the first capillary tubes 27a and 27b) only during heating. A separator, 29 is a pipe through which gas refrigerant flows from above the sererator 28 to an injection circuit 33 to the compressor 2 during heating, 30 is a check valve, and 31 is a second pipe for heating.
In the capillary tube, the pressure changes from intermediate pressure to low pressure in this second capillary tube 31, and the outdoor heat exchanger 4
It is evaporated and vaporized, and returns to the compressor 2 via the four-way valve 3.
32 is a capillary tube for heating injection exit through which the liquid refrigerant stored below the separator 28 passes; 33 and 34 are injection exit circuits to the compressor 2 connected to the cylinder of the compressor 2. 35 is a cooling capillary tube for cooling injection; during cooling, part of the liquid refrigerant condensed in the outdoor heat exchanger 4 is transferred into the cylinder of the compressor as refrigerant enough to cool the gas being compressed. The length of the capillary tube through which the quantity can flow is determined, and the capillary tube is connected to the injection circuits 33 and 34 to the compressor. 36
a, 36b are pipes 37 taken out from between the gas side solenoid valves 16a, 16b and the three-way valves 15a, 15b.
The pressure equalizing capillary tubes 36a and 37b are provided in the pressure equalizing capillary tubes 36a and 37b.
6b is connected to the suction pipe 20 and connected to the indoor unit 10.
This is provided to equalize the pressure of the condensed refrigerant in the indoor heat exchanger of the stopped indoor unit with the pressure on the suction pipe side and gradually recover the high-pressure liquid refrigerant when either one of a and 10b is stopped. It is something that

In the above configuration, normal refrigeration cycle operation is performed during cooling. That is, the gas refrigerant compressed by the compressor 2 is transferred to a four-way valve 3, an outdoor heat exchanger 4, where it is condensed, and a first capillary tube 5 for cooling (some liquid refrigerant is transferred to an injector for refrigerant). ), check valve 6a,
6b, liquid side solenoid valves 7a, 7b, three-way valves 8a, 8b
(At this time, since the heating solenoid valve 24 is closed, the flow does not flow to the check valves 26a and 26b.)
0a, 10b second capillary tube 11a,
11b, indoor heat exchanger 13a, 13b, three-way valve 1
5a, 15b, check valves 17a, 17b, four-way valve 3, and accumulator 18.
If the high pressure becomes abnormally high, the high pressure pressure regulating valve 2
1 opens to return the liquid refrigerant condensed in the heat exchange section 23 to the suction pipe 20, reducing the load on the compressor. Next, during heating, the gas refrigerant compressed by the compressor 2 is transferred to the four-way valve 3, the gas-side solenoid valves 16a and 16b, and the three-way valve 1.
5a, 15b, and the indoor heat exchangers 13a, 13b of the indoor units 10a, 10b.
2a, 12b, three-way valve 8a, 8b, check valve 6a,
6b, the check valves 26a, 2
6b, the first capillary tube 2 for heating
7A, 27b, heating solenoid valve 24, separator 2
It reaches 8. In this separator 28, the liquid refrigerant serves as the main circuit of the check valve 30, the second capillary tube 31 for heating, the outdoor heat exchanger 4, and the heating circuit of the four-way valve 3; is compressor 2
At the same time, a part of the gas refrigerant flows through the piping 29 and becomes a gas-liquid mixed refrigerant, which is a mixture of liquid refrigerant and gas refrigerant. It flows through the injection exit circuit 33 to the compressor 2 and is injected into the cylinder of the compressor 2. At this time, most of the gas-liquid mixed refrigerant is gas refrigerant from the pipe 29, and only a small amount of liquid refrigerant is from the capillary tube 32 of the heating injection extension.
In addition, when the indoor temperature, range, or outdoor temperature rises and the compressed high-temperature, high-pressure refrigerant becomes abnormally high, creating an overload condition, the pressure in the pipe 22 also rises, and the high-pressure pressure regulating valve 21 begins to open. The liquid refrigerant condensed in the heat exchange section 23 flows through the high-pressure pressure regulating valve 21 and enters the suction pipe 2.
0 and returns to the accumulator 18, reducing the load on the compressor 2. Next, during heating, when either of the indoor units 10a, 10b is stopped, liquid refrigerant is prevented from accumulating in the indoor heat exchanger 10a, 10b that is stopped. The side where the gas side solenoid valves 16a and 16b are stopped is closed, and the pipes 37a and 37b, as well as the pressure equalization capillary tubes 36a and 36b, are closed.
It gradually flows through the stopped side and flows into the suction pipe 20,
The refrigerant is recovered while reducing the pressure of the stopped high pressure circuit to the suction pipe 20 side.

Also, for example, while the indoor unit 10a is operating, the indoor unit 10b is simultaneously operated for a short time,
Also, when the indoor unit 10a is stopped and only the indoor unit 10b is operated, the gas side solenoid valve 16
a is closed, the refrigerant in this system flows through the piping 37a and the pressure equalization capillary tube 36a, and is gradually recovered to the suction pipe 20, and also flows through the first heating capillary tube 27a, the heating solenoid valve 24, and , the separator 28, and the second capillary tube 31 for heating through the check valve 30 are at an intermediate pressure, and this intermediate pressure allows the refrigerant in the stopped pipe to be recovered and returned to the indoor unit in operation. 10b, the amount of refrigerant circulated through the compressor 2 will not temporarily become insufficient and the temperature will rise, which would place a burden on the compressor.

In this way, the present invention allows the check valve 30 to
By keeping the heating solenoid valve 24 normally closed, the separator 28 is disconnected from the main cooling circuit.
Refrigerant does not accumulate in the separator 18. On the other hand, during heating operation, the gas refrigerant coming out from above the separator 28 occupies the main stream of the injection refrigerant returned to the injection extraction circuit 33 to the compressor 2, and the gas refrigerant flows through the piping 29. The flowing gas refrigerant and the liquid refrigerant flowing from the lower part of the separator 28 to the compressor 2 through the injection exit circuit 34 and the heating injection exit capillary tube 32 are merged, resulting in a gas-liquid mixture containing mainly gas refrigerant. Since the refrigerant is injected into the cylinder of the compressor 2, the discharge temperature can be increased and the heating capacity can be improved compared to the conventional injection of mainly liquid refrigerant. or,
Compared to the conventional method, which mainly returns a gas-liquid mixture refrigerant even during overload, the present invention allows almost liquefied liquid refrigerant to flow through the high-pressure pressure regulating valve 21 in the heat exchange section 23. A large amount of refrigerant can be obtained by reducing the volume of refrigerant, and the load on the compressor can be reduced. Furthermore, compared to the conventional method in which the liquid refrigerant in the stopped indoor heat exchanger is recovered from an intermediate pressure during heating through an injection exit, the present invention enables the recovery of liquid refrigerant between the gas side solenoid valve and the three-way valve during heating. By creating a height difference so that the pressure is equalized from a certain high pressure side, it can be recovered quickly and has the effect of reducing the rate at which liquid refrigerant accumulates in the indoor unit.

[Brief explanation of drawings]

FIG. 1 is a refrigerant control circuit diagram of a conventional heat pump type air conditioner/heater, and FIG. 2 is a refrigerant control circuit diagram of a heat pump type air conditioner/heater according to an embodiment of the present invention. 2...Compressor, 3...Four-way valve, 4...Outdoor heat exchanger, 7a, 7b...Liquid side solenoid valve, 15a, 15
b... Three-way valve, 16a, 16b... Gas side solenoid valve, 20... Suction pipe, 21... High pressure pressure regulating valve,
24... Solenoid valve for heating, 26a, 26b... Check valve, 27a, 27b... First capillary tube for heating, 28... Separator, 29... Piping,
32... Capillary tube for heating injection extension, 36a, 36b... Capillary tube for pressure equalization.

Claims (1)

[Claims] 1 In a heat pump type air conditioner equipped with a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, a pressure reduction mechanism, indoor heat exchangers 13a, 13b, etc., the outdoor heat exchanger 4 is The overload prevention circuit is connected to the high pressure regulating valve 21 through the heat exchange section 23 disposed in a part of the circuit, and is connected to the suction pipe 20 side of the compressor 2 from the high pressure regulating valve 21. Three-way valves 8a, 8b and liquid side solenoid valves 7a, 7
Check valves 26a, 26b led out from between b, first capillary tubes 27a, 27b for heating, and solenoid valve 2 for heating that opens during heating and closes during cooling.
4 to the separator 28, and an injection extraction circuit 34 in which the liquid refrigerant flows from the separator 28 through an injection extraction capillary tube 32 for heating, and joins the liquid refrigerant into an injection extraction circuit 33 which returns the gas refrigerant from the separator 28 to the compressor. and gas side solenoid valves 16a, 16
A refrigerant control device for a heat pump type air conditioner/heater, which is led out from between the three-way valves 15a and 15b and connected to the suction pipe 20 of the compressor 2 via pressure equalization capillary tubes 36a and 36b.