JPH07280378A - Heat pump type air conditioner - Google Patents

Abstract

PURPOSE:To suppress a temperature rise of a compressor at the time of heating, to prevent freezing of a drain pan and to reduce a quantity of liquid refrigerant retained in an outdoor heat exchanger at the time of cooling. CONSTITUTION:An auxiliary heat exchanger 18A is installed under an outdoor heat exchanger 18, and connected in series with the exchanger 18. A bypass circuit 29 is connected between either an outlet or an inlet of the exchanger 18A and a discharge tube 31 for connecting a compressor 1 to a four-way valve 2 via a flow regulating tube 19 and a switching valve 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type air conditioner.

[0002]

2. Description of the Related Art A refrigerant circuit diagram of a conventional heat pump type air conditioner is shown in FIG. During the cooling operation, the high temperature and high pressure refrigerant gas discharged from the compressor 1 enters the plural circuits of the outdoor heat exchanger 18 through the four-way valve 2 as shown by the solid arrow, and radiates the outside air here. Is condensed and liquefied into a high-pressure liquid refrigerant.

This liquid refrigerant passes through distribution pipes 17a, 17b and 17c, merges in a distributor 16, and adiabatically expands in a cooling throttle 15 to become a low-pressure liquid gas two-phase refrigerant.

This two-phase refrigerant is connected to the pipe joint 13 and the connecting pipe 1.
2, the pipe joint 11 and the check valve 10 to be distributed by the distributor 8, pass through the distribution pipes 7a and 7b, and enter the plural circuits of the indoor heat exchanger 6, where the indoor air is cooled. It vaporizes and becomes a low-pressure gas refrigerant.

This gas refrigerant passes through the pipe joint 5, the connecting gas pipe 4, the pipe joint 3, and the four-way valve 2 and then the accumulator 22.
The gas refrigerant, which has separated the non-evaporated liquid refrigerant, is sucked into the compressor 1 through the suction pipe 23 and compressed again.

On the other hand, during the heating operation, the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 passes through the four-way valve 2, the pipe joint part 3, the connecting gas pipe 4, and the pipe joint part 5 as shown by the broken line arrow. And enters the indoor heat exchanger 6, where it is condensed and liquefied into high-pressure liquid refrigerant.

The liquid refrigerant merges in the distributor 8 through the distribution pipes 7a and 7b and then adiabatically expands in the heating throttle 9 to become a low-pressure liquid gas two-phase refrigerant.

This two-phase refrigerant consists of a pipe joint 11 and a connecting pipe 1.
2, pipe joint 13, check valve 14, distributor 16, distribution pipe 17a, 1
It enters the outdoor heat exchanger 18 through 7b and 17c, and is evaporated and vaporized there to become a low-pressure gas refrigerant. This gas refrigerant returns to the compressor 1 through the accumulator 22 and the suction pipe 23 and is compressed again.

When the temperature of the compressor 1 rises abnormally due to changes in operating conditions, the on-off valve 20 provided in the liquid refrigerant injection circuit 28 is opened. Then, during the cooling operation, the high-pressure liquid refrigerant condensed in the outdoor heat exchanger 18 passes through the liquid refrigerant injection circuit 28 and the opening / closing valve 20, the flow rate adjusting pipe 21, and the suction pipe 23, which are passed to the compressor 1. It is injected to cool it.

During heating operation, the low-pressure liquid-gas two-phase refrigerant flowing through the check valve 14 is injected into the compressor 1 through the liquid-refrigerant injection circuit 28, the on-off valve 20, the flow rate adjusting pipe 21, and the suction pipe 23. .

When the outdoor heat exchanger 18 is frosted during the heating operation, the heat absorption efficiency thereof is reduced by the frosting. Therefore, the defrost operation is performed by switching the four-way valve 2 to the cooling operation state.

[0012]

[Problems to be Solved by the Invention]

(1) In the above conventional heat pump type air conditioner, the low-pressure liquid gas two-phase refrigerant that has passed through the check valve 14 in order to prevent the temperature of the compressor 1 from rising during the heating operation of the refrigerant injection circuit 28. It is then injected into the compressor 1. Therefore, the check valve
Since the pressure difference between the refrigerant pressure after passing through 14 and the refrigerant pressure in the suction pipe 23 is small, it is not possible to supply the compressor 1 with the liquid refrigerant in an amount necessary for cooling the compressor 1. However, during the heating operation, the temperature of the compressor 1 is likely to be high, which causes a problem that the operating range is narrowed.

(2) Since the outdoor heat exchanger 18 is mounted on the drain pan 35 as shown in FIG. 6, the outdoor heat exchanger 18 also cools the drain pan 35 to a low temperature during the heating operation. Therefore, during the defrost operation, the outdoor heat exchanger 18
Drain water dripping from the surface of the
There was a problem that the ice 36 was frozen on the ice 35, and this ice 36 grew every defrosting operation to press and deform the pipe 18B in the outdoor heat exchanger 18.

(3) During the heating operation, the difference in the amount of heat radiated between the circuits of the outdoor heat exchanger 18 causes unevenness in the amount of condensation of the refrigerant, and as a result, the refrigerant staying in the pipe 18B of the outdoor heat exchanger 18 There was a problem that the amount increased.

[0015]

The present invention has been invented to solve the above-mentioned problems, and is characterized in that an auxiliary heat exchanger is installed in the lower portion of the outdoor heat exchanger and the outdoor heat exchanger is installed outdoors. In addition to connecting in series with the heat exchanger, a bypass circuit in which a flow rate adjusting pipe and an on-off valve are installed between either the outlet or inlet of this auxiliary heat exchanger and the discharge pipe connecting the compressor and the four-way valve I have connected.

Another feature is that a flow rate adjusting pipe and an on-off valve are provided between one of the outlet and inlet of the auxiliary heat exchanger and the refrigerant pipe connecting the four-way valve and the indoor heat exchanger. The bypass circuit was connected.

A refrigerant bypass circuit in which a flow rate adjusting pipe and an on-off valve are interposed can be connected between any one of the outlet and inlet of the auxiliary heat exchanger and the suction pipe of the compressor.

Still another feature is that a pipe for liquid gas two-phase refrigerant connecting a parallel circuit of a cooling throttle and a check valve and a parallel circuit of a heating throttle and a check valve, and a compressor A liquid refrigerant injection circuit in which a flow rate adjusting pipe and an on-off valve are installed is connected between the suction pipe and the check valve at the outlet side of the check valve in the parallel circuit of the cooling throttle and the check valve. It is because the flow rate adjustment pipe was installed in series.

A flow rate adjusting pipe can be installed in series with the check valve on the outlet side of the check valve in the parallel circuit of the heating throttle and the check valve.

[0020]

[Function] When the opening / closing valve installed in the bypass circuit is opened during the heating operation, a part of the high-temperature / high-pressure gas refrigerant discharged from the compressor is opened in the bypass circuit and the opening / closing valve installed in the bypass circuit and the flow rate. It enters the auxiliary heat exchanger or the outdoor heat exchanger through the adjusting pipe, and radiates heat to the outside air to be condensed.

When the on-off valve installed in the liquid refrigerant injection circuit is opened, the high-pressure or medium-pressure liquid refrigerant passes through the liquid refrigerant injection circuit, the on-off valve installed in the liquid refrigerant injection circuit, and the flow rate adjusting pipe to the compressor. It is injected and cools it.

During the heating operation, when the low-pressure two-phase refrigerant throttled by the heating throttle passes through the auxiliary heat exchanger and enters the outdoor heat exchanger, the auxiliary heat exchanger has a flow path resistance, so that the auxiliary heat The refrigerant pressure in the exchanger is higher than the refrigerant pressure in the outdoor heat exchanger, and the temperature of the auxiliary heat exchanger is higher than the outside air temperature, which is the heat absorption source, so the surface of the auxiliary heat exchanger does not frost and drains. It does not freeze.

During the cooling operation, the liquid refrigerant condensed in each circuit of the outdoor heat exchanger flows into the auxiliary heat exchanger, so that the liquid refrigerant hardly accumulates nonuniformly in each circuit.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A first embodiment of the invention is shown in FIG. As shown in FIG. 1, an auxiliary heat exchanger 18A configured by dividing the outdoor heat exchanger 18 is installed in the lower part of the outdoor heat exchanger 18, and the auxiliary heat exchanger 18A is connected in series with the outdoor heat exchanger 18. Has been done.

One end of the liquid refrigerant injection circuit 28 is connected to the refrigerant pipe 30 connecting the distributor 16 and the auxiliary heat exchanger 18A, and the other end is connected to the suction pipe 23 of the compressor 1 as in the conventional one. .

Further, one end of a bypass circuit 29 is connected to a discharge pipe 31 of the compressor 1 connecting the compressor 1 and the four-way valve 2, and the other end is a parallel circuit 40 of a cooling throttle 15 and a check valve 14. Is connected to a refrigerant pipe 32 that connects the auxiliary heat exchanger 18A and the auxiliary heat exchanger 18A. An opening / closing valve 24 and a flow rate adjusting pipe 19 are interposed in the bypass circuit 29. Other configurations are similar to those of the conventional one shown in FIG. 5, and corresponding members are designated by the same reference numerals.

During heating operation, the refrigerant, as indicated by the broken line, is a compressor 1, a discharge pipe 31, a four-way valve 2, a pipe joint 3, a connecting gas pipe 4, a pipe joint 5, an indoor heat exchanger 6, and a distribution pipe. 7a, 7
b, distributor 8, heating throttle 9, pipe joint 11, connecting pipe 1
2, pipe joint 13, check valve 14, pipe 32, auxiliary heat exchanger 18A
, Pipe 30, distributor 16, distribution pipes 17a, 17b, 17c, outdoor heat exchanger 18, four-way valve 2, accumulator 22, suction pipe 23
And then returns to the compressor 1.

Auxiliary heat exchanger 18A, pipe 30, distributor 16, distribution pipes 17a, 17b, 17c due to flow resistance of the auxiliary heat exchanger 18
The refrigerant vaporization pressure in A is higher than the refrigerant vaporization pressure in the outdoor heat exchanger 18, so the refrigerant vaporization temperature in the auxiliary heat exchanger 18A is higher than that in the outdoor heat exchanger 18 and at the heat absorption source. It can be higher than the temperature of some outside air.

Therefore, in the heating operation at low outside air temperature, even when the outdoor heat exchanger 18 is frosted, the auxiliary heat exchanger 18A is not frosted, and the drain in the drain pan 35 is frozen. Can be prevented.

On the other hand, since a part of the gas refrigerant is diverted from the discharge pipe 31 to the bypass circuit 29, the amount of the gas refrigerant flowing into the indoor heat exchanger 6 is reduced, so that the condensation in the indoor heat exchanger 6 is reduced. The pressure drops. Also, the auxiliary heat exchanger 18A
Since the medium-pressure liquid refrigerant partially evaporated in (1) flows into the outdoor heat exchanger 18, the refrigerant evaporation pressure in the outdoor heat exchanger 18 rises. By these, the operating pressure of the compressor 1, that is, the load is reduced, so that the temperature of the compressor 1 is also reduced.

When the temperature of the compressor 1 rises abnormally during the heating operation, the open / close valves 20 and 24 are opened. Then, a part of the high-temperature and high-pressure gas refrigerant discharged from the compressor 1 enters the bypass circuit 29 from the discharge pipe 31, passes through the on-off valve 24, the flow rate adjusting pipe 19, and the pipe 32 and enters the auxiliary heat exchanger 18A. enter,
Here, by exchanging heat with the outside air and condensing, it becomes a medium-pressure liquid refrigerant. This medium-pressure liquid refrigerant enters the liquid refrigerant injection circuit 28 from the pipe 30, is injected into the compressor 1 through the on-off valve 20, the flow rate adjusting pipe 21, and the suction pipe 23 to cool the compressor 1.

However, since the pressure difference between the pressure of the medium-pressure liquid refrigerant partially evaporated in the auxiliary heat exchanger 18A and the refrigerant pressure in the suction pipe 23 of the compressor 1 becomes large, a sufficient amount is obtained. Since this liquid refrigerant can be supplied to the compressor 1, the compressor 1 can be effectively cooled.

During the cooling operation, the refrigerant is the compressor 1, the discharge pipe 31, the four-way valve 2, the outdoor heat exchanger as shown by the solid arrow.
18, distribution pipes 17a, 17b, 17c, distributor 16, pipe 30, auxiliary heat exchanger 18A, pipe 32, cooling throttle 15, pipe joint 13,
Connection pipe 12, pipe joint 11, check valve 10, distributor 8, distribution pipes 7a, 7b, indoor heat exchanger 6, pipe joint 5, connection gas pipe 4, pipe joint 3, four-way valve 2, accumulator 22 and the suction pipe 23 in this order, and then returns to the compressor 1.

Since the liquid refrigerant condensed in the outdoor heat exchanger 18 has a smaller flow resistance than the gas refrigerant, the distribution pipe 17a
, 17b and 17c, the distributor 16, and the pipe 30 to collect in the auxiliary heat exchanger 18A, it is possible to prevent the liquid refrigerant from accumulating in the pipe 18B of the outdoor heat exchanger 18 as in the conventional case.

Although not shown, one end of the bypass circuit 29 can be connected to the refrigerant pipe 30. Even in this case, the same effect as described above can be obtained.

A second embodiment is shown in FIG. In this embodiment, the other end of the bypass circuit 29 has the four-way valve 2
Is connected to a refrigerant pipe 33 that connects the indoor heat exchanger 6 and the indoor heat exchanger 6.
The liquid refrigerant injection circuit 28 is omitted. The other structure is the same as that of the first embodiment shown in FIG. 1, and the corresponding members are designated by the same reference numerals.

When the temperature of the compressor 1 rises abnormally during the heating operation, the open / close valve 24 is opened. Then, a part of the high temperature / high pressure gas refrigerant discharged from the compressor 1 enters the bypass circuit 29 through the four-way valve 2 and the pipe 33, and passes through the on-off valve 24, the flow rate adjusting pipe 19, and the pipe 32 for auxiliary heat exchange. Enters vessel 18A and condenses here.

Since a part of the gas refrigerant flows into the bypass circuit 29 from the pipe 33, the amount of refrigerant flowing into the indoor heat exchanger 6 is reduced, and the refrigerant condensing pressure in the indoor heat exchanger 6 is reduced accordingly. . On the other hand, the medium-pressure liquid refrigerant partially evaporated in the auxiliary heat exchanger 18A flows into the outdoor heat exchanger 18, and the refrigerant evaporation pressure in the outdoor heat exchanger 18 rises. As a result, the load on the compressor 1 decreases, and the temperature of the compressor 1 also decreases.

During the cooling operation, a part of the liquid refrigerant condensed in the auxiliary heat exchanger 18A enters the bypass circuit 29, and the flow rate adjusting pipe 19,
The liquid refrigerant returns to the pipe 33 through the on-off valve 24, and the liquid refrigerant is transferred to the four-way valve 2,
It is separated by the accumulator 22 and accumulates at the bottom. Then, the compressor 1 is cooled by being sucked into the compressor 1 together with the refrigerating machine oil from the oil return hole 22B provided in the lower portion of the U-shaped pipe 22A of the accumulator 22.

FIG. 3 shows a third embodiment. In this third embodiment, one end of the bypass circuit 29 is connected to the pipe 30, and one end of the liquid refrigerant injection circuit 28 is connected to the pipe 30.
Connected to 32. Even in this case, the second shown in FIG.
The same effect as that of the embodiment can be obtained.

FIG. 4 shows a fourth embodiment. In the fourth embodiment, a flow rate adjusting pipe 25 is connected to the downstream side of the check valve 14, and a cooling throttle 15 is connected in parallel to the check valve 14 and the flow rate adjusting pipe 25. . And
A flow rate adjusting pipe 26 is connected to the downstream side of the check valve 10, and a heating throttle 9 is connected in parallel to the check valve 10 and the flow rate adjusting pipe 26.

Further, one end of the liquid refrigerant injection circuit 28 is a parallel circuit.
It is connected to a liquid gas two-phase refrigerant pipe 34 connecting 43 and 44.

During the heating operation, the liquid gas two-phase refrigerant flowing out from the check valve 14 is throttled by the flow rate adjusting pipe 25, so that the pressure at the inlet of the check valve 14 rises. Therefore, when the on-off valve 20 is closed, the gas-liquid two-phase refrigerant whose pressure has risen is supplied to the compressor 1 through the liquid refrigerant injection circuit 28, so that a sufficient amount for cooling the compressor 1 is obtained. Refrigerant may be supplied to the compressor 1.

Further, during the cooling operation, the liquid gas two-phase refrigerant adiabatically expanded by the cooling throttle 15 passes through the check valve 10 and is throttled by the flow rate adjusting pipe 26, and then flows into the distributor 8. As a result, since the two-phase refrigerant is throttled by the flow rate adjusting pipe 26, the pressure on the upstream side of the check valve 10 rises, and the refrigerant pressure at the outlet of the cooling throttle 15 also rises accordingly. Therefore, since the high-pressure two-phase refrigerant is supplied to the compressor 1 through the liquid refrigerant injection circuit 29, a sufficient amount of refrigerant for cooling the compressor 1 can be supplied to the compressor 1.

[0045]

According to the present invention, (1) during heating operation, a part of the high-pressure gas refrigerant can be bypassed to the bypass circuit, so that the temperature rise of the compressor 1 can be suppressed. (2) Since the liquid refrigerant having a higher pressure than before can be flown into the liquid refrigerant injection circuit even during the heating operation, the liquid refrigerant can be supplied to the compressor in an amount sufficient to cool it. (3) During heating operation, the temperature of the auxiliary heat exchanger can be higher than the outside air temperature, which can prevent frost formation on the auxiliary heat exchanger and prevent freezing of drain water. Can be prevented. (4) During the cooling operation, the liquid refrigerant condensed in each circuit of the outdoor heat exchanger is collected in the auxiliary heat exchanger, so that the liquid refrigerant accumulated in each circuit can be almost eliminated.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a partial refrigerant circuit diagram of an air conditioner according to a second embodiment of the present invention.

FIG. 3 is a partial refrigerant circuit diagram of an air conditioner according to a third embodiment of the present invention.

FIG. 4 is a refrigerant circuit diagram of an air conditioner according to a fourth embodiment of the present invention.

FIG. 5 is a refrigerant circuit diagram of a conventional air conditioner.

FIG. 6 is a partial perspective view showing a mounted state of an outdoor heat exchanger of a conventional air conditioner.

[Description of symbols] 18 Outdoor heat exchanger 18A Auxiliary heat exchanger 40 Parallel circuit 15 Cooling throttle 14 Check valve 41 Parallel circuit 9 Heating throttle 10 Check valve 24, 20 Open / close valve 19, 21 Flow rate control pipe 1 Compressed Machine 6 Indoor heat exchanger 2 Four-way valve 28 Liquid refrigerant injection circuit 29 Bypass circuit

Claims (5)

[Claims] 1. A compressor, a four-way valve, an outdoor heat exchanger, a parallel circuit of a cooling throttle and a check valve, a parallel circuit of a heating throttle and a check valve, and an indoor heat exchanger are connected in this order. In this heat pump type air conditioner, an auxiliary heat exchanger is installed in the lower part of the outdoor heat exchanger and is connected in series with the outdoor heat exchanger, and either the outlet or inlet of the auxiliary heat exchanger and the compression A heat pump type air conditioner characterized in that a bypass circuit in which a flow rate adjusting pipe and an opening / closing valve are interposed is connected between a machine and a discharge pipe connecting the four-way valve. 2. A compressor, a four-way valve, an outdoor heat exchanger, a parallel circuit of a cooling throttle and a check valve, a parallel circuit of a heating throttle and a check valve, and an indoor heat exchanger are connected in this order. In the heat pump type air conditioner consisting of, an auxiliary heat exchanger is installed in the lower part of the outdoor heat exchanger and is connected in series with the outdoor heat exchanger, and with either the outlet or inlet of this auxiliary heat exchanger,
A heat pump type air conditioner characterized in that a bypass circuit in which a flow rate adjusting pipe and an on-off valve are interposed is connected between a refrigerant pipe connecting the four-way valve and the indoor heat exchanger. 3. A heat pump type characterized in that a bypass circuit having a flow rate adjusting pipe and an opening / closing valve is connected between one of the outlet and inlet of the auxiliary heat exchanger and the suction pipe of the compressor. Air conditioner. 4. A compressor, a four-way valve, an outdoor heat exchanger, a parallel circuit of a cooling throttle and a check valve, a parallel circuit of a heating throttle and a check valve, and an indoor heat exchanger are connected in this order. In the heat pump type air conditioner, the liquid gas two-phase refrigerant pipe connecting the parallel circuit of the cooling throttle and the check valve and the parallel circuit of the heating throttle and the check valve, and the suction of the compressor A liquid refrigerant injection circuit in which a flow rate adjusting pipe and an on-off valve are interposed is connected between the pipe and the check valve at the outlet side of the check valve in the parallel circuit of the cooling throttle and the check valve. A heat pump type air conditioner characterized by installing flow rate adjustment pipes in series. 5. The heat pump according to claim 4, wherein a flow rate adjusting pipe is installed in series with the check valve on the outlet side of the check valve in the parallel circuit of the heating throttle and the check valve. Type air conditioner.