JPH0413576Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a heat pump type air conditioner in which a plurality of indoor units are connected in parallel to one outdoor unit.

(Prior Art) An example of a conventional refrigerant circuit of this type of heat pump type air conditioner is shown in FIG.

When heating two indoor units A and B connected in parallel to one outdoor unit C at the same time, the high temperature and high pressure gas refrigerant discharged from the compressor 1 is heated as shown by the solid line arrow. It branches off through the four-way valve 2 and flows into indoor unit A and indoor unit B in parallel through gas side branch pipes 17A and 17B. The indoor air then enters the indoor heat exchangers 3A and 3B, where the indoor air blown by the indoor fans 14A and 14B is heated and condensed and liquefied to become a high-pressure liquid refrigerant. This liquid refrigerant is transferred to the liquid side branch pipe 16
After being depressurized by cooling throttles 4A, 4B installed in A, 16B, the air flows through heating on-off valves 5A, 5B, check valves 9A, 9B, joins and enters receiver 18.
The refrigerant that has exited the receiver 18 enters the heating throttle 11, where it is throttled and adiabatically expanded to become a low-temperature, low-pressure gas-liquid two-phase flow. Next, this gas-liquid two-phase refrigerant enters the outdoor heat exchanger 12, where it absorbs heat from the outside air sent by the outdoor fan 15, evaporates, and becomes a low-temperature, low-pressure gas refrigerant, which spreads in all directions. It returns to the compressor 1 via the valve 2 and the accumulator 13. During this operation, the heating on-off valves 5A and 5B are open, and the cooling on-off valves 8A and 8B are both closed.

During heating operation, when any one of the two indoor units A and B, for example indoor unit B, is to be stopped, the operation of the indoor fan 14B is stopped.
Furthermore, when the thermostat of indoor unit B is turned off, that is, when the temperature in the room where indoor unit B is installed reaches a predetermined value, the rotational speed of indoor fan 14B is reduced by a signal from the thermostat that detects this. do.

When cooling the two indoor units A and B at the same time, switch the four-way valve 2 to the dashed line position, close the heating on-off valves 5A and 5B, and close the cooling on-off valve 8.
Let A and 8B be open. Then, the refrigerant discharged from the compressor 1 passes through the four-way valve 2 as shown by the broken line arrow.
After being condensed and liquefied in the outdoor heat exchanger 12, it branches off through the check valve 10 and the receiver 18, and is further connected to the cooling on-off valves 8A, 8B and check valves installed in the liquid side branch pipes 16A, 16B. After passing through the valves 6A, 6B and adiabatic expansion in the cooling throttles 4A, 4B, and then being evaporated in the indoor heat exchangers 3A, 3B, the gas side branch pipe 1
7A and 17B, and return to the compressor 1 via the four-way valve 2 and the accumulator 13.

To stop any one unit, for example, indoor unit B, during this cooling operation, the operation of the indoor fan 14B is stopped, and when the thermostat of indoor unit B is turned off, the rotational speed of the indoor fan 14B is reduced.

During defrosting operation, the refrigerant is circulated as shown by the broken line arrows, similar to during cooling operation.

(Problems to be Solved by the Invention) In the above-mentioned conventional air conditioner, when one indoor unit, e.g. Instead, a large amount of refrigerant liquefies and accumulates inside the indoor heat exchanger 3B and the gas side branch pipe 17B. Then, the amount of refrigerant circulating within the indoor unit A during operation becomes insufficient, resulting in so-called gas-low operation, so in order to prevent this, it is necessary to fill the refrigerant circuit with more refrigerant than necessary. To deal with this, as mentioned above, even when one of the indoor units B is stopped or the thermostat is turned off, the heating on-off valve 5B is opened, and the operation of the outdoor fan 14B is stopped or its rotational speed is reduced. However, in this case, the refrigerant is in the indoor heat exchanger 3.
Since the refrigerant flows through in a gaseous state without being substantially cooled by B, the amount of refrigerant circulated within the refrigerant circuit becomes excessive, resulting in a so-called overcharge state. Therefore,
A receiver 18 must be installed to store the refrigerant for this overcharge. Furthermore, if the heating on-off valve 5B is opened, the refrigerant is transferred to the indoor heat exchanger 3.
Since heat is radiated when flowing through B, there was a problem in that the capacity of indoor unit A was reduced accordingly.

(Means for Solving the Problems) The present invention was proposed in order to solve the above problems, and its gist is to provide a single outdoor unit equipped with a compressor, an outdoor heat exchanger, etc. A plurality of indoor units having indoor heat exchangers, etc. are connected to the unit in parallel, and a heating on-off valve and a check valve are installed in each liquid side branch pipe between each indoor heat exchanger and the outdoor heat exchanger. In a heat pump type air conditioner that has a parallel circuit with a cooling shutoff valve and a check valve, a thermo-off throttle is connected in parallel to the heating shutoff valve, and a stop throttle is connected in parallel with the heating shutoff valve. The heat pump type air conditioner is characterized in that a parallel circuit formed by interposing a shutoff valve and a shutoff valve in series is connected in parallel.

(Function) Since the present invention has the above configuration, the heating on-off valve and the pause on-off valve of the indoor unit that turns off the thermostat are closed during heating operation.
The liquid refrigerant flows out through the thermo-off throttle. During heating operation, the heating on-off valve of the indoor unit that is inactive is closed, and the inactive on-off valve is open, so the liquid refrigerant passes through the thermo-off restrictor and the inactive restrictor, which are connected in parallel with this heating on-off valve. leak.

(Embodiment) An embodiment of the present invention is shown in FIG. 2
Two indoor units A and B are one outdoor unit C.
are connected in parallel. Indoor units A and B each include indoor heat exchangers 3A and 3B, and outdoor unit C includes a compressor 1 and an outdoor heat exchanger 12. Each liquid side branch pipe 16A, 16B between each indoor heat exchanger 3A, 3B and outdoor heat exchanger 12
are equipped with cooling on/off valves 8A, 8B and check valve 9, respectively.
A, 9B parallel circuit is interposed, and the check valves 6A, 6B are connected in parallel to the heating on-off valves 5A, 5B, and the thermo-off apertures 7A,
7B are connected in parallel, and the rest aperture 20
A, 20B and the stop valves 19A, 19B are connected in parallel in a parallel circuit.

The rest of the structure is the same as the conventional one shown in FIG. 2, except that the receiver 18 is omitted, and corresponding members are given the same reference numerals.

When heating the two indoor units A and B at the same time, the refrigerant circulates as shown by the solid arrows, similar to the conventional system shown in FIG.

During heating operation, when any one of the two indoor units A and B, for example, indoor unit B, is to be suspended, its heating on-off valve 5B is closed, the suspension on-off valve 19B is opened, and the indoor fan 14B is shut down. stop.
On the other hand, the heating on-off valve 5A of the indoor unit A to be operated is opened, the suspension on-off valve 19A is closed, and the indoor fan 14A is operated. Then, the refrigerant discharged from the compressor 1 branches through the four-way valve 2 and flows into the indoor units A and B through the gas side branch pipes 17A and 17B. The refrigerant that has flowed into the indoor unit A is condensed and liquefied by heating the indoor air sent by the indoor fan 14A in the indoor heat exchanger 3A, and then passes through the cooling throttle 4 interposed in the liquid side branch pipe 16A.
A. Enters the heating throttle 11 through the heating opening/closing portion 5A and the check valve 9A, where it undergoes adiabatic expansion and then enters the outdoor exchanger 12, where it absorbs heat from the outside air blown by the outdoor fan 15. After being evaporated and vaporized, it returns to the compressor 1 via the four-way valve 2 and the accumulator 13. On the other hand, since the heating on-off valve 5B is closed, the gas refrigerant that has flowed into the indoor unit B liquefies and accumulates in the indoor heat exchanger 3B, but this liquid refrigerant passes through the cooling throttle 4B and stops at the thermo-off throttle 7B. After flowing in parallel through the on-off valve 19B and the stop throttle 20B, the refrigerant passes through the check valve 9B, joins with the refrigerant flowing out from the indoor unit A, and returns to the compressor 1 together with the refrigerant.

When turning off the thermostat of any one unit, for example, indoor unit B, during heating operation, its heating on-off valve 5B and pause on-off valve 19B are closed, and the rotational speed of the indoor fan 14B is reduced. Heating on/off valve 5A of indoor unit A which is operated on the other hand
And the shutoff valve 19A is opened and the indoor fan 1
4A is operated at the normal rotation speed. Then, the gas refrigerant that has flowed into the indoor unit B with the thermostat turned off liquefies and accumulates in the indoor heat exchanger 3B, and this liquid refrigerant flows out from the indoor unit A via the cooling throttle 4B, the thermostat off throttle 7B, and the check valve 9B. It joins with the refrigerant and returns to the compressor 1 together with it.

Therefore, when the indoor unit B turns off the thermostat, the refrigerant passes through the thermo-off aperture 7B, and when it stops, the refrigerant flows through the thermo-off aperture 7B and the stop aperture 20B in parallel. Since the gas refrigerant is hardly condensed and liquefied in the indoor heat exchanger 3B, there is a large resistance when flowing through these throttles 7B and 20B, and therefore the gas refrigerant is not condensed and liquefied in the indoor heat exchanger 3B.
The liquid refrigerant accumulates therein, and this liquid refrigerant gradually flows out little by little through the throttles 7B and 20B.

During heating operation, a certain amount of the refrigerant that has flowed into the indoor unit B, which is turned off or stopped, accumulates in the indoor heat exchanger 3B as a liquid refrigerant. 7B or through the pause throttle 20B in small amounts. Thus, even when the heating on-off valve 5B is closed, the indoor heat exchanger 3B and the gas side branch pipe 1 are closed, as in the case where the heating on-off valve 5B is closed in the conventional one shown in FIG.
It is possible to prevent the refrigerant from liquefying and completely accumulating in 7B. As a result, even when one indoor unit B is turned off or stopped, the amount of refrigerant circulated through the operating indoor unit A does not change much compared to when two indoor units A and B are operated for heating at the same time. The receiver that stores excess refrigerant can be eliminated. In addition, since a certain amount of liquid refrigerant accumulates in the indoor heat exchanger 3B of the indoor unit B when the thermostat is off or inactive, it is possible to prevent the amount of refrigerant circulating in the refrigerant circuit from becoming excessive. Furthermore, since the amount of refrigerant passing through the indoor unit B when the thermostat is off or inactive is small, and the amount of heat released is also small, there is almost no reduction in the performance of the indoor unit A during operation.

Furthermore, when the indoor unit B is at rest, the liquid refrigerant flows out little by little through the thermo-off throttle 7B and the hibernation throttle 20B, and when the indoor unit's thermostat is off, the liquid refrigerant flows out only through the thermo-off throttle 7B, so it flows out when the thermostat is off. The amount of liquid refrigerant will be even smaller than when it is stopped. As a result, it is possible to prevent liquid refrigerant from accumulating when indoor unit B is at rest, that is, when indoor fan 14B is stopped, and at the same time, it is possible to prevent liquid refrigerant from accumulating when indoor unit B is inactive, that is, when indoor unit B is in a low-speed circuit, when indoor unit B is in a low-speed circuit. The deterioration in performance can be further reduced.

(Effects of the invention) In this invention, even if some of the indoor units are thermo-off or stopped, the amount of refrigerant circulating through the operating indoor units is reduced to the same amount as that of all the indoor units operating. Since this is almost the same as the case, there is no need for a receiver to store excess refrigerant, and it is possible to prevent refrigerant from overcharging to the indoor unit during operation. Furthermore, since the amount of refrigerant flowing through the indoor unit when the thermostat is off or the indoor unit is inactive is small, and the amount of heat released is also small, the decrease in the performance of the indoor unit during operation can be reduced.

Further, when the indoor unit is at rest, the liquid refrigerant flows out through the thermo-off throttle and the halt throttle, so that it is possible to prevent the refrigerant liquid from accumulating in the indoor unit when the indoor fan is at rest. Further, when the thermostat of the indoor unit is turned off, the liquid refrigerant flows out only through the thermostat off throttle, so that the decrease in the performance of the indoor unit during low-speed operation of the indoor unit when the thermostat is turned off can be further reduced.

[Brief explanation of the drawing]

FIG. 1 is a refrigerant circuit diagram of the first embodiment of the present invention,
FIG. 2 is a refrigerant circuit diagram of a conventional heat pump type air conditioner. 1...Compressor, 12...Outdoor heat exchanger, C...
Outdoor unit, 3A, 3B... Indoor heat exchanger,
A, B... Indoor unit, 16A, 16B... Liquid side branch pipe, 5A, 5B... Heating on/off valve, 6A,
6B...Check valve, 8A, 8B...Cooling on/off valve,
9A, 9B...Check valve, 7A, 7B...Thermo-off throttle, 20A, 20B...Stop throttle, 19
A, 19B... Shutdown on-off valve.

Claims (1)

[Scope of utility model registration request] A plurality of indoor units each having an indoor heat exchanger etc. are connected in parallel to one outdoor unit having a compressor, an outdoor heat exchanger etc., and each unit between each indoor heat exchanger and the outdoor heat exchanger is In a heat pump air conditioner in which a parallel circuit of a heating on-off valve and a check valve and a parallel circuit of a cooling on-off valve and a check valve are interposed in the liquid side branch pipe, the heating on-off valve In contrast, a heat pump air conditioner is characterized in that a thermo-off throttle is connected in parallel, and a parallel circuit is connected in parallel with a stop throttle and a stop opening/closing valve interposed in series.