JPH09257346A - Heat pump air-conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of a defrosting solenoid valve in a heat pump air-conditioner having a heat pump cycle which includes a compressor, a four- way valve, an outdoor heat exchanger, an expansion mechanism, an indoor heat exchanger and an accumulator. SOLUTION: A defrosting bypass circuit 20 for connecting the liquid side of an outdoor heat exchanger 3 to the inlet side of an accumulator 10 is provided, and a defrosting solenoid valve 21 is mounted in the circuit 20. At the time of defrosting operation, the valve 21 is opened by the command of defrost control means 24, and a four-way valve 2 is switched to a cooling cycle side to supply the hot gas from the compressor 1 via the valve 2, exchanger 3 and the circuit 20 in this order to the accumulator 10.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a heat pump type air conditioner.

[0002]

2. Description of the Related Art An example of a conventional air conditioner of this type is shown in FIG. Multiple units in one outdoor unit O (two units in the figure)
Indoor units A and B are connected to refrigerant pipes 11A, 12A, 11B and 12B
Connected through. During the cooling operation, the gas refrigerant discharged from the inverter-driven compressor 1 enters the outdoor heat exchanger 3 via the four-way valve 2 as shown by the solid arrow, and radiates the outside air blown by the outdoor fan 4 to the outside air. By doing so, it is condensed and liquefied.

This liquid refrigerant is divided into two parts, and the expansion mechanism 5A,
After being adiabatically expanded by being squeezed by 5B, the connection tool 6A,
6B and the connecting refrigerant pipes 11A and 11B to enter the indoor heat exchangers 7A and 7B of the indoor units A and B, where they absorb heat from the indoor air blown by the indoor fans 8A and 8B and evaporate. This gas refrigerant is connected refrigerant pipe 12A, 12B, connection
After joining through 9A, 9B and solenoid on-off valves 13A, 13B, they return to the compressor 1 through the four-way valve 2, accumulator 10.

During heating operation, the four-way valve 2 is switched in the opposite manner to the above, and the refrigerant circulates in the opposite direction as indicated by the broken line arrow. When a large amount of frost adheres to the surface of the outdoor heat exchanger 3 due to this heating operation, the defrost operation is performed.

During this defrosting operation, the defrosting solenoid valve 15 is opened, so that a part of the hot gas discharged from the compressor 1 is part of the hot gas bypass circuit 14 and the defrosting current valve as indicated by the one-dot chain line. After passing through 15, it merges with the branched refrigerant, melts the frost adhering to the surface when passing through the outdoor heat exchanger 3, and then returns to the compressor 1 via the four-way valve 2 and the accumulator 10.

Current is supplied to the drive motor 16 of the compressor 1 from an AC power source 18 via an inverter 17, and the inverter 17
The number of rotations of the compressor 1 changes according to the frequency.

[0007]

In the above conventional heat pump type air conditioner, during the defrost operation, the hot gas of high temperature and high pressure discharged from the compressor 1 is interposed in the hot gas bypass circuit 14 Solenoid valve 15
Therefore, the defrosting electromagnetic valve 15 must be of high quality capable of withstanding high temperature and high pressure hot gas, and therefore, there is a problem that the cost thereof increases.

[0008]

The present invention has been invented to solve the above-mentioned problems, and the gist of the invention is to provide a compressor, a four-way valve, an outdoor heat exchanger, an expansion mechanism, an accumulator, etc. In a heat pump type air conditioner having a heat pump cycle consisting of, a defrost bypass circuit connecting the liquid side of the outdoor heat exchanger and the inlet side of the accumulator is provided and a defrost electromagnetic valve is provided in this bypass circuit. During the defrost operation, the hot gas from the compressor is switched to the four-way valve, the outdoor heat exchanger, and the defrost bypass circuit in this order by opening the defrost electromagnetic valve and switching the four-way valve to the cooling cycle side. A heat pump type air provided with a defrost control means for allowing the air to flow into the accumulator. In the sum machine.

During defrost operation, however, the defrost control valve is opened by the defrost control means and the four-way valve is switched to the cooling cycle side so that hot gas from the compressor is used for the four-way valve, the outdoor heat exchanger, and the defroster. The bypass circuit is caused to flow into the accumulator through this order.

[0010]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the invention is shown in FIG. A defrost bypass circuit 20 that connects the liquid side of the outdoor heat exchanger 3 and the inlet side of the accumulator 10 is provided,
A defrost electromagnetic valve 21 and a capillary tube 22 are interposed in the defrost bypass circuit 20.

When a command from the defrost switch 23 is input to the defrost control means 24, the defrost control means 24
Outputs to the defrost electromagnetic valve 21 to open it and at the same time outputs to the four-way valve 2 to switch it to the cooling cycle side.

Then, the hot and high-pressure hot gas discharged from the compressor 1 enters the outdoor heat exchanger 3 via the four-way valve 2 as shown by the one-dot chain line, where the frost adhering to the surface thereof. The temperature is lowered by melting. Then, this gas passes through the defrost bypass circuit 20, the defrost electromagnetic valve 21 interposed therein, the capillary tube 22, and the accumulator 10 in this order and returns to the compressor 1. Other configurations and operations are the same as those of the conventional one shown in FIG. 2, and corresponding members are denoted by the same reference numerals and description thereof is omitted.

During the defrost operation, however, the low-temperature gas refrigerant cooled by melting the frost in the outdoor heat exchanger 3 flows through the defrost electromagnetic valve 21, so that the defrost electromagnetic valve 21 is heated to high temperature and high pressure. It does not have to be of high quality to withstand and therefore its cost can be significantly reduced.

[0014]

According to the present invention, during defrost operation,
The low-temperature gas refrigerant that has been cooled by melting frost in the outdoor heat exchanger flows through the defrost solenoid valve, so this defrost solenoid valve does not need to be of high quality that can withstand high temperatures and pressures. , The cost can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a refrigerant circuit diagram of a conventional heat pump type air conditioner.

[Explanation of symbols]

 1 compressor 2 4 way valve 3 outdoor heat exchanger 5A, 5B expansion mechanism 7A, 7B indoor heat exchanger 10 accumulator 20 defrost bypass circuit 21 defrost solenoid valve

Front page continuation (72) Inventor Kazumi Okamura 3-chome, Asahi-cho, Nishibiwajima-cho, Nishikasugai-gun, Aichi Prefecture Mitsubishi Heavy Industries, Ltd. Air-conditioner manufacturing factory (72) Takeshi Ito, Iwazuka-cho, Nakamura-ku, Nagoya Mitsubishi Heavy Industries Nagoya Research Center

Claims (1)

[Claims] 1. A heat pump type air conditioner comprising a heat pump cycle including a compressor, a four-way valve, an outdoor heat exchanger, an expansion mechanism, an accumulator, etc., wherein a liquid side of the outdoor heat exchanger and an inlet side of the accumulator. A defrosting bypass circuit for connecting the defroster and a defrosting solenoid valve interposed in the bypass circuit, and during defrosting operation, the defrosting solenoid valve is opened, and the four-way valve is switched to the cooling cycle side. A heat pump type air conditioner comprising defrost control means for allowing hot gas from the above to flow into the accumulator through the four-way valve, the outdoor heat exchanger, and the defrost bypass circuit in this order.