JPS5971963A - Heat pump type refrigeration cycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pump type refrigeration cycle.

In a conventional heat pump type refrigeration cycle, as shown in Fig. 1, a compressor 1. Four-way switching valve 3. Outdoor heat exchanger4. The expansion device 5 and the indoor heat exchanger 6 are sequentially connected in an annular manner, and during cooling operation, high-temperature, high-pressure refrigerant gas is sent from the compressor 1 to the outdoor heat exchanger 4 as shown by the solid arrow, where it is condensed. The refrigerant gas is evaporated in the indoor heat exchanger 6 via the expansion device 5, and during heating operation, high-temperature, high-pressure refrigerant gas from the compressor 1 is reversely circulated as shown by the broken line arrow to perform heating.

Generally, in this type of refrigeration cycle, when defrosting is performed during heating operation, the four-way switching valve 3 is switched to flow high-temperature, high-pressure refrigerant gas to the outdoor heat exchanger 4. However, when the four-way switching valve 3 is switched, the high-pressure liquid refrigerant in the indoor heat exchanger 6 flows back into the compressor 1.
The refrigerant accumulates in the accumulator 2 to prevent liquid compression, and the amount of refrigerant circulating through the refrigeration cycle is insufficient, making it impossible to defrost the fluid sufficiently. However, heating operation cannot be performed during this time, which leads to a drop in room temperature, which impairs comfort.

The present invention was made with the aim of eliminating the above-mentioned drawbacks, and is a heat pump type that prevents liquid from returning to the compressor during defrosting, performs effective defrosting, and shortens defrosting time. It provides a refrigeration cycle.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 2 is a refrigerant circuit diagram of a heat pump type refrigeration cycle according to the present invention, and FIG. Explanatory diagram of the operation of the second solenoid valve, Figures 4 to 6
The figure is a refrigerant circuit diagram showing another embodiment of the present invention.

Note that solid arrows indicate the flow of refrigerant during cooling operation, and dashed arrows indicate the flow of refrigerant during heating operation.

In FIG. 2, 11 is a compressor that compresses refrigerant gas;
12 is an accumulator for preventing liquid return; 13 is a four-way switching valve that switches between cooling operation and heating operation; 14 is an outdoor heat exchanger that acts as a condenser during cooling operation and as an evaporator during heating operation; 15 is an expansion valve or An expansion device such as a capillary tube, 16 an indoor heat exchanger which acts as an evaporator during cooling operation and a condenser during heating operation, and 17 an outdoor heat exchanger outlet and an indoor heat exchanger inlet in this embodiment. The bypass flow path is a flow path connecting the four-way switching valve 13 including the outdoor heat exchanger 14 and the expansion device 15, other embodiments of which are shown in FIGS. 4 to 6. The bypass flow path may be located anywhere as long as it communicates an arbitrary point with any point in the flow path connecting the four-way switching valve 13 including the indoor heat exchanger 16 and the expansion device 15. 18 is a first solenoid valve provided in the bypass flow path; 19 is a compressor 1;
This is a second electromagnetic valve provided in a flow path connecting the suction side of the four-way switching valve 13 and the four-way switching valve 13.

FIG. 3 shows the operations of the four-way switching valve I3, the first solenoid valve 18, and the second solenoid valve 19. When switching the refrigeration cycle, these valves operate as shown in FIG. That is, first, the first solenoid valve 18 is opened, and the second solenoid valve 19 is opened.
After closing, the first electromagnetic valve 18 closes with a delay, and the four-way switching valve 13 switches. After further delay, the second
Solenoid valve 19 is opened.

Next, the operation of the refrigeration cycle will be explained.

In this refrigeration cycle, during normal heating operation, the first solenoid valve 18 is always closed and the second solenoid valve 19 is always open, which is exactly the same as the operating state of the conventional cycle shown in FIG.

Now, when switching the refrigeration cycle to start defrosting in response to a signal from a timer de-icer or a frost detection device (not shown) during heating operation, first the first solenoid valve 18
is opened, and the second solenoid valve 19 is closed. This can be done at the same time or slightly delayed.

By doing so, the high temperature and high pressure liquid refrigerant in the indoor heat exchanger 16 moves into the outdoor heat exchanger 14 without flowing back into the compressor 11. Due to the heat of the transferred high-temperature, high-pressure liquid refrigerant, a portion of the frost adhering to the outdoor heat exchanger 14 begins to melt.

In this way, after the liquid refrigerant in the indoor heat exchanger 16 has finished moving into the outdoor heat exchanger 14, the first electromagnetic valve 18 is closed and the four-way switching valve 13 is switched. This may be done by detecting the pressure or temperature of the outdoor heat exchanger 14, or may be controlled temporally from the first opening of the first electromagnetic valve 18.

After that, if the second solenoid valve 19 is opened, the refrigeration cycle is completely switched to a reverse cycle, and the outdoor heat exchanger 14 is removed by the high temperature and high pressure refrigerant gas discharged from the compressor 11. Frost begins.

In this way, in this refrigeration cycle, when the refrigeration cycle is switched, the liquid refrigerant flows back into the accumulator 12 of the compressor 11 and is held in the condenser without stagnation, so efficient operation is possible immediately after the refrigeration cycle is switched. Therefore, effective defrosting is possible, liquid compression overcurrent due to liquid returning to the compressor 11, etc. can be prevented, and reliability can be improved.

Furthermore, when switching to heating operation after defrosting, similarly, after opening the first solenoid valve 18 and closing the second solenoid valve 19,
After a delay, the first solenoid valve 18 is closed and the four-way switching valve 13 is switched, and then the second solenoid valve 19 is opened.

According to the heat pump type refrigeration cycle of the present invention, as shown in the double series, when defrosting is carried out during heating operation, effective defrosting can be carried out in a short time, so the drop in room temperature is small, and the outdoor heat is Since the exchanger can always be used in an efficient state with little frost, efficient and comfortable air conditioning can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a refrigerant circuit diagram of a conventional heat pump refrigeration cycle, Fig. 2 is a refrigerant circuit diagram of a heat pump refrigeration cycle according to the present invention, and Fig. 3 shows a four-way switching valve, a first solenoid valve, and a 2 Operation explanatory diagram of solenoid valve, 4th
5 and 6 are refrigerant circuit diagrams showing other embodiments of the present invention. 11: compressor, 12 near-accumulator, 13: four-way switching valve, 14: outdoor heat exchanger, 15: expansion device, 16 two indoor heat exchangers, 17: bypass passage, 18: first solenoid valve, 19: Second solenoid valve. Agent Patent attorney Aihiko Fukushi (and 2 others) Figure 1 111〉-■1 Figure 3

Claims (1)

[Claims] 1 Compressor, four-way switching valve, indoor heat exchanger, expansion device,
The indoor heat exchangers are sequentially connected in an annular manner, and any point in the flow path connecting the four-way switching valve including the outdoor heat exchanger and the expansion device, the four-way switching valve including the indoor heat exchanger, and the expansion device are connected. A bypass flow path communicating with any point in the flow path connecting the devices is provided, a first electromagnetic valve is provided in the bypass flow path, and a second electromagnetic valve is provided in the flow path connecting the compressor suction side and the four-way switching valve. In a heat pump refrigeration cycle equipped with a solenoid valve, when switching the refrigeration cycle from heating operation to dehumidification operation, the first solenoid valve opens, the second solenoid valve closes → the first solenoid valve closes, and the four-way switching valve switches → the second solenoid valve. A heat pump type refrigeration cycle characterized by control in the order of valve opening.