JPS6152909B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pump device including an indoor heat exchanger and a plurality of outdoor heat exchangers.

Conventionally, this type of device has a compressor 1, an indoor heat exchanger 2, and a plurality of units (in this figure, 3 units), as shown in FIG.
) outdoor heat exchangers 3, 4, 5, four-way valve 6, receiver 7, expansion valves 8, 9, 10, check valve 11,
12, 13, communication passages 14, 15, 16, valve 17,
18, 19, 20, 21, 22, an expansion valve 23, and a check valve 24, and these devices are connected to pipes 25, 2.
6, 27, 28, and 29 are connected. valve 17,
18, 19, 20, 21, and 22 function as switching valves that selectively connect the outlet sides of the outdoor heat exchangers 3, 4, and 5 to the suction side and the discharge side of the compressor 1. .

When the four-way valve 6 is placed in the position shown and the heating cycle is operating, the outdoor heat exchanger 3,
High-temperature, high-pressure gas (hereinafter referred to as hot gas) discharged from the compressor 1 when frost formation is observed on 4 and 5.
A portion of the air is guided to the indoor heat exchangers 3, 4, and 5 in order for defrosting. That is, first, as shown in the figure, the valve 17 is closed and the valve 18 is opened to introduce the hot gas to the outdoor heat exchanger 3 for defrosting. The condensed refrigerant liquid of the hot gas generated at this time descends and is guided to the secondary side of the expansion valves 9, 10 through the communication passages 14, 16, and the refrigerant gas sent from the receiver 7 and passed through the expansion valves 9, 10.
The refrigerant enters the outdoor heat exchangers 4 and 5 together with the refrigerant liquid, evaporates, and is led to the suction port of the compressor 1 via valves 19 and 21 and pipes 28.

Next, the valves 18 and 19 are closed, the valves 17 and 20 are opened, and the hot gas is guided to the outdoor heat exchanger 4 for defrosting, and then the outdoor heat exchanger 5 is defrosted in the same manner.

FIG. 2 shows another conventional example in which the condensed refrigerant liquid generated by defrosting is transferred to a valve 30, 31 or 32 and a pipe 33.
The voltage is then returned to the receiver 7, which is the high voltage side.

In addition, there are other types that are configured to return the condensed refrigerant liquid to the refrigerant liquid supply header (high pressure side), etc., but it is difficult to return the condensed refrigerant liquid in stable operating conditions, and it has the following drawbacks. had.

When returning condensed refrigerant liquid to the low pressure side: (1) A special pressure reduction device is required for each coil to return the liquid refrigerant from the highest pressure in the refrigerant cycle to the low pressure side.

(2) To coils where the amount of refrigerant evaporation has decreased due to frost formation,
Since liquid refrigerant is supplied, at the beginning of defrosting, the liquid refrigerant is directly sent to the coil outlet side. Therefore, the expansion valve of the coil to which the refrigerant liquid has returned operates in the closing direction, and the ratio of the amount of return liquid refrigerant supplied to the coil increases. It is difficult to control the amount of this returned liquid refrigerant so that it is not sucked into the pressure condenser in the form of droplets.

(3) As a result, the amount of refrigerant liquid that dissolves in the lubricating oil increases, making the lubrication system more likely to fail.

In addition, when returning the condensed refrigerant to the high pressure side, (1) In order to return the condensed refrigerant, there must be a sufficient pressure difference between the hot gas line and the receiver or refrigerant supply header only during defrosting. Special equipment is required to produce this.

(2) This device for generating differential pressure creates piping resistance during normal operation, increasing the power of the compressor.

(3) During defrosting, if the hot gas pressure is increased to create a differential pressure, the power of the compressor will increase, and if the pressure of the receiver or liquid refrigerant supply header is lowered, the refrigeration capacity will increase even more than the coil reduction. Or heating capacity decreases.

The present invention aims to provide a heat pump system that does not require a special pressure reducing device or differential pressure generator, and the pressures on the high pressure side and low pressure side do not change even during defrosting, except for the above-mentioned drawbacks of the conventional ones. It is something to do.

The present invention provides a heat pump device including a compressor, an indoor heat exchanger, and a plurality of outdoor heat exchangers, in the middle of a refrigerant path from the outlet of the indoor heat exchanger to the inlet of the outdoor heat exchanger. is provided with an economizer, the gas phase part of the economizer is connected to the intermediate pressure stage of the compressor, and the outlet side of each of the outdoor heat exchangers is connected to the suction side of the compressor via a switching valve. The inlet side of each of the outdoor heat exchangers is irreversibly connected to the liquid phase part of the economizer via an expansion valve, and is selectively connected to the liquid phase section of the economizer via an expansion valve. (A) The switching on-off valve is connected to the secondary side of the inlet expansion valve of the economizer and requires defrosting when frost forms on the outdoor heat exchanger. (B) Open the return on-off valve and connect the inlet side of the outdoor heat exchanger to the inlet expansion valve of the economizer. This heat pump device is characterized in that it is configured to be connected to the secondary side and perform defrosting.

The present invention will be described by way of example with reference to the drawings.

Although FIG. 3 shows the flow of a heating cycle as an example, it can also be used as a cooling cycle with the four-way valve 6, check valves 11, 12, 13, expansion valve 23, check valve 24, etc. shown in FIG. Alternatively, the switching may be performed.

In FIG. 3, the outlet of the indoor heat exchanger 2,
An economizer 34 is provided between the inlets of the outdoor heat exchangers 3, 4, and 5. The economizer 34 shown in this figure is of a closed type. The conduit 27 from the receiver 7 divides the conduit 35 into a bypass 36 . The pipe line 35 is connected to the inlet side of the outdoor heat exchangers 3, 4, 5 via a heat exchanger 37, a pipe line 38, and expansion valves 8, 9, 10. Bypass 3
6 is connected to the intermediate pressure stage of the compressor 1 via an expansion valve 39, a heat exchanger 37, and a bypass 40. The secondary side of the expansion valves 8, 9, 10, that is, the inlet side of each outdoor heat exchanger 3, 4, 5, is provided with valves 41, 42,
43 and further via a common line 44 to the secondary side of the expansion valve 39 at the inlet of the economizer 34.

To explain the action during defrosting, when the outdoor heat exchangers 3, 4, and 5 are frosted, first close the valve 17, open the valve 19, and guide the hot gas to the outdoor heat exchanger 3 for defrosting. Do frost. The valve 41 is opened and the condensed refrigerant liquid generated during defrosting is transferred to the irreversible expansion valve 8.
cannot pass through, so it is guided through the valve 41 and through the conduit 44 to the intermediate pressure section on the secondary side of the expansion valve 39. At this time, the refrigerant from the pipe line 35 is introduced into the other outdoor heat exchangers 4, 5, and continues to operate regardless of the return refrigerant liquid from the pipe line 44, so the pressure is high. There is no risk of causing a change in the pressure on the side or low pressure side, and there is no need to cause a change.

Next, valves 18, 19, and 41 are closed, and valves 17 and 2 are closed.
0 and 42 are opened to defrost the outdoor heat exchanger 4, and then defrost the outdoor heat exchanger 5 in the same manner.

In this way, defrosting is performed by sequentially and selectively applying a similar process to outdoor heat exchangers that require defrosting.

The number of outdoor heat exchangers is not limited to three, but any plural number can be used, and the defrosting switching order and number can be arbitrarily selected.

As the economizer 34, a flash economizer can be used in addition to a closed economizer. In this case, the return condensate refrigerant should be guided to the economizer chamber.

FIG. 4 shows a heat pump cycle diagram when a closed economizer is used, and FIG. 5 shows a heat pump cycle diagram when a flash economizer is used.

According to the present invention, the condensate refrigerant is returned to the economizer, which has an intermediate pressure on the refrigerant cycle, eliminating the need for a special pressure reducing device or differential pressure generating device, and leaving the operating condition of the coil that is not defrosted. is the same as before defrosting, there is no disadvantage that the amount of liquid refrigerant sucked into the compressor increases only during defrosting, and therefore the refrigerant dissolving into the lubricating oil does not increase compared to normal operation.
To provide a heat pump device in which the pressures on the high-pressure side and low-pressure side during defrosting are the same as before defrosting, and the disadvantages such as an increase in compressor power and a further decrease in refrigerating capacity than the decrease in coils occur. This has an extremely large practical effect.

[Brief explanation of the drawing]

Figures 1 and 2 are flow diagrams of the conventional example, Figure 3 is a flow diagram of the embodiment of the present invention, Figure 4 is its heat pump cycle diagram, and Figure 5 is a heat pump cycle diagram of another embodiment. It is. 1...Compressor, 2...Indoor heat exchanger, 3,
4, 5... Outdoor heat exchanger, 6... Four-way valve, 7...
...Receiver, 8,9,10...Expansion valve, 11,
12, 13... Check valve, 14, 15, 16... Communication path, 17, 18, 19, 20, 21, 22...
Valve, 23... Expansion valve, 24... Check valve, 25, 2
6, 27, 28, 29...pipeline, 30, 31, 3
2...Valve, 33...Pipeline, 34...Economizer, 35...Pipeline, 36...Bypass, 37...
Heat exchanger, 38... Pipeline, 39... Expansion valve, 40
...Bypass, 41, 42, 43...Valve, 44...
...Pipe line.

Claims (1)

[Claims] 1. In a heat pump device comprising a compressor, an indoor heat exchanger, and a plurality of outdoor heat exchangers, a refrigerant from the outlet of the indoor heat exchanger to the inlet of the outdoor heat exchanger. An economizer is provided in the middle of the path, the gas phase part of the economizer is connected to the intermediate pressure stage of the compressor, and the outlet side of each of the outdoor heat exchangers is connected to the compressor through a switching valve. The inlet side of each of the outdoor heat exchangers is irreversibly connected to the liquid phase part of the economizer via an expansion valve, and a return on/off valve. (A) for an outdoor heat exchanger that is connected to the secondary side of the inlet expansion valve of the economizer through the switch and that requires defrosting when frost occurs on the outdoor heat exchanger; (B) Open the return on-off valve to connect the inlet side of the outdoor heat exchanger to the inlet of the econoiser. A heat pump device characterized in that it is configured to be connected to the secondary side of an expansion valve to perform defrosting. 2. The apparatus of claim 1, wherein the economizer is a closed economizer. 3. The apparatus according to claim 1, wherein the economizer is a flash economizer, and the condensed refrigerant generated by defrosting is guided into the economizer chamber of the flash economizer. 4 If frost occurs on two or more of the plurality of outdoor heat exchangers, the connections in (A) and (B) above are
2. The apparatus according to claim 1, wherein defrosting is performed selectively and sequentially on a plurality of heat exchangers that require defrosting.