JPS6030431B2 - Defrosting device for heat pump refrigerant circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in defrosting devices for air source heat pumps.

In a heat pump cold soot circuit where the heat source side heat exchanger is installed outdoors and is formed by multiple air heat exchangers, water vapor in the atmosphere condenses on the surface of the air heat exchanger, and the frozen frost is removed by high-temperature cold gas. Hot gas defrosting methods that involve melting are commonly used.

However, with this type of conventional system, liquid cooling soot tends to accumulate in the air heat exchanger, and when defrosting is finished, the refrigerant in a liquid state is sucked into the compressor, giving various effects to the compressor. It had drawbacks. The present invention, which was made in view of these points, will be explained below with reference to the drawings. 1 is a soot compressor, 2 is a user-side heat exchanger, and 3 is a plurality of air heat exchangers 4, 4', 4^. 5 is a pressure reducing device such as an expansion valve that operates during cooling, 6 is a device for exchanging heat between high temperature discharge refrigerant gas and low temperature return soot gas, 7 and 8 are a check valve and a liquid receiver installed in parallel with the pressure reducing device 5 and opened during heating;
9, 9', 9''... are pressure reducing devices such as expansion valves that operate during heating, and 10, 10', 10... are pressure reducing devices that are opened during normal heating and cooling operation and closed during defrosting. 9,9
11, a timed on-off valve connected in series to ',9''...
11', 11... and 12, 12', 12... are side pipes that bypass the expansion valve and timed on-off valve, and check valves that close during heating and open during cooling, 13, 13', 1
3... and 14, 14', 14"... are solenoid valves arranged in parallel to the cold soot outlet pipe 15 during heating, and the solenoid valves 13, 13', 13"... It is connected to the compressor 1 via a four-way switching valve 16, which is opened during normal heating and cooling operation and closed during defrosting, while solenoid valves 14, 14', 14'',
... are connected to the discharge side 18 of the compressor via an auxiliary pressure reducing device 17, and are controlled to be closed during normal heating and cooling operation and opened during defrosting.

, 19, 19', 19"... are air blowers attached to the respective air heat exchangers 4, 4', 4... and independently controlled; 20, 20', 20"...・ is a second pressure reducing device that connects the inlets of the air heat exchanger during heating.

When the device of the present invention having such a configuration is operated as a heating cycle, the four-way valve 16 is in the state shown in the figure, and cold soot flows as shown by the solid line arrow to obtain hot water for heating from the user-side heat exchanger 2. be able to.

On the other hand, during the cooling cycle, the four-way valve 16 is in the state shown by the dashed-dotted line, and the refrigerant flows in the direction opposite to the direction shown by the dashed-dotted line.In a circuit with a check valve, the refrigerant flows in the direction shown by the dashed-dotted line
Cold water for air conditioning can be obtained from the user-side heat exchanger 2. Therefore, in the heating cycle, if frost forms on the air heat exchanger 3, the solenoid valve 13 is closed at the four-way valve position shown in the figure.
When the solenoid valve 14 is closed and the solenoid valve 14 is opened, the high-temperature, high-pressure refrigerant gas discharged from the compressor 1 has its top pressure reduced by the auxiliary pressure reducing device 17, and then passes through the air heat exchanger 4 as shown by the dotted line.
The refrigerant flows into the heat exchanger and melts the frost adhering to the heat exchanger, and becomes a liquid refrigerant. However, the opposite sides of the check valve 12 and the expansion valve 9 both pass through the liquid receiver 8 and become high-pressure. state, the liquid cooled soot is transferred to a second pressure reducing device (capillary tube in the illustrated embodiment)
0 to another air heat exchanger 4', where it again obtains heat from the atmosphere, returns to the compressor 1 via a solenoid valve 13' and a four-way valve 16, and is recirculated.

During this defrosting operation, the blower 19 is stopped, and
If all the air heat exchangers 4, 4', 4'', etc. are not in defrosting operation at the same time, the liquid refrigerant generated in the air heat exchanger 4 during defrosting will be transferred to the air heat exchanger during heating operation. Since it flows into the compressor 4' and is vaporized, the compressor 1 is
Defrosting operation can be continued while preventing liquid backflow.

Furthermore, at the end of defrosting, the solenoid valve 14 is first closed, the solenoid valve 13 is opened, and the liquid cooling butterfly in the air heat exchanger 4 is cooled in the same way as the other air heat exchangers 4, 4', 4''... When the time-limited on-off valve 10 is opened after a period of time when the amount of liquid cooling soot becomes normal, the air heat exchanger 4 returns to the defrosted heat source side heat exchanger in normal heating operation.

Such a defrosting operation is similarly performed in any air heat exchanger 4', 4'', etc. as appropriate.

As described above, in the defrosting device according to the present invention, when defrosting the plurality of air heat exchangers forming the heat source side heat exchanger of the heat pump cold soot circuit, the liquid refrigerant condensed in the heat exchanger during defrosting is
Since the defrosting refrigerant is immediately led to another air heat exchanger to ensure a sufficient circulating amount of defrosting refrigerant, rapid defrosting can be performed. In addition, the control of the solenoid valve and the action of the timed on/off valve eliminates refrigerant stagnation after defrosting.
Since liquid backflow to the compressor can be completely prevented during reuse, the downtime for defrosting each air heat exchanger is extremely short, and overall efficient heat pump operation can be maintained. It is.

[Brief explanation of the drawing]

The figure is a refrigerant circuit diagram of a heat pump incorporating an embodiment of the defrosting device according to the present invention. 1...Compressor, 2...Using side heat exchanger, 3...Heat source side heat exchanger, 4, 4', 4''...
... Air heat exchanger, 5 ... Pressure reduction device, 9.
..... Expansion valve, 10 ..... Timed opening/closing valve, 11
... Side pipe, 12 ... Check valve, 13,
To 13', 13... 14, 14', 14''...
... Solenoid valve, 16... Four-way switching valve, 17...
...Auxiliary pressure reducing device.

Claims (1)

[Claims] 1. A heat pump refrigerant circuit in which the refrigerant circuit is composed of a compressor, a user side heat exchanger, a heat source side heat exchanger, a pressure reducing device, a four-way switching valve, etc., and the heat source side heat exchanger is formed by multiple air heat exchangers. In each air heat exchanger, the refrigerant inlet line during heating is connected to the expansion valve and the timed opening/closing valve by a series circuit of an expansion valve and a timed opening/closing valve, and a check valve that closes during heating and opens during cooling. A side pipe that bypasses the on-off valve is provided, and two solenoid valves that are opened and closed independently are arranged in parallel in the refrigerant outlet pipe during heating, and one of the solenoid valves is a four-way switching valve. A defrosting device for a heat pump refrigerant circuit, characterized in that the other solenoid valve is connected to the compressor via an auxiliary pressure reducing device to the discharge side of the compressor.