JP2000234818A - Refrigerant supercooling mechanism of air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling effect by supercooling a refrigerant that is unloaded from a heat exchanger. SOLUTION: In an air-conditioning device 1, a compressor 2, an outdoor heat exchanger 7, a pressure reduction device 20, and an indoor heat exchanger 21 are connected for circulating a refrigerant. The air-conditioning device 1 is provided with the refrigerant supercooling mechanism of the air-conditioning device, where the liquid refrigerant extraction port of a gas/liquid separator 35 in the middle of the outdoor heat exchanger 7 is connected to the inlet of a heat transfer pipe 30, in a cooling receiver 12 that is provided between the outlet of the outdoor heat exchanger 21 and the pressure reduction device 20 via a first throttle valve 37, and the outlet of the heat transfer pipe 30 is connected to the inlet of the compressor 2. A second throttle valve 10 is provided between the outlet of the outdoor heat exchanger 7 and the cooling receiver 12, thus promoting the supercooling of the refrigerant in the receiver 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant supercooling mechanism of an air conditioner which connects a compressor, an outdoor heat exchanger, a pressure reducing device, and an indoor heat exchanger to circulate a refrigerant.

[0002]

2. Description of the Related Art Conventionally, a gas-liquid separator is provided in the middle of a condenser (heat exchanger), and a liquid refrigerant extraction port of the gas-liquid separator is connected to an outlet of the heat exchanger. A refrigerating apparatus designed to improve the efficiency and reduce the size of the heat exchanger has already been proposed (for example, Japanese Patent Application Laid-Open No. 8-327181). However, in this case, the liquid refrigerant extracted by the gas-liquid separator is simply mixed into the refrigerant flowing out of the heat exchanger, so that it is not used for supercooling the refrigerant, thus further improving the cooling effect. I can't expect it.

[0003]

SUMMARY OF THE INVENTION The refrigerant from the heat exchanger is supercooled to further improve the cooling effect.

[0004]

According to a first aspect of the present invention, there is provided an air conditioner in which a refrigerant is circulated by connecting a compressor, an outdoor heat exchanger, a decompression device, and an indoor heat exchanger. The liquid refrigerant extraction port of the gas-liquid separator in the middle is connected via a first throttle valve to the inlet of a heat transfer tube in a cooling receiver provided between the outlet of the outdoor heat exchanger and the pressure reducing device. Is connected to an inlet of a compressor. According to a second aspect of the present invention, there is provided the air conditioner according to the first aspect, wherein a second throttle valve is provided between an outlet of the outdoor heat exchanger and the cooling receiver to promote supercooling of the refrigerant in the cooling receiver. This is a refrigerant supercooling mechanism.

[0005]

FIG. 1 shows a state of a cooling operation of an air conditioner 1 according to the present invention. An outlet 3 of a compressor 2 driven by an engine or the like has a passage 4, a four-way valve 5, and a passage 6.
And the outlet 9 of the outdoor heat exchanger 7 is connected to the inlet 13 of the cooling receiver 12 via a passage 11 having a second throttle valve 10 in the middle. The cooling receiver 12 has an upper gas phase portion 14 and a lower liquid refrigerant 15, and an outlet 16 is connected to an indoor unit 18 via a passage 17. The indoor unit 18 includes a plurality of passages 22 having a pressure reducing device 20 (throttle valve) and an indoor heat exchanger 21, and a merging passage 23 of the passages 22 passes through a four-way valve 5, a passage 24, an accumulator 25, a passage 26, and a compressor 2 is connected to the inlet 27 of the second.

The second throttle valve 10 throttles the upstream passage 11 during the cooling operation shown in the drawing, and completely liquefies the refrigerant at the outlet of the outdoor heat exchanger 7 to cool or cool the liquid-phase refrigerant in the cooling receiver 12. It has a function to promote the cooling action. Conventionally, a heating expansion valve is provided at this location (fully open during cooling)
Is arranged, the illustrated second throttle valve 10 is a two-way type which also has the function of a conventional heating expansion valve.

[0007] The cooling receiver 12 is provided with a heat transfer tube 30 described later in the liquid refrigerant 15 therein. Conventionally, a receiver having no heat transfer tube 30 is disposed at this location.
The cooling receiver 12 is formed by, for example, utilizing a function of pooling surplus refrigerant when the number of heat exchangers 21 used in the indoor units 18 decreases.

The temperature sensors 31, 32 on the inlet side and the outlet side (during cooling operation) of the indoor heat exchanger 21 of the indoor unit 18 are connected to the throttle valve 20, and the same temperature signals are supplied from the temperature sensors 31, 32. This means that the liquid refrigerant passes through the outlet of the indoor heat exchanger 21, that is, the indoor heat exchanger 2
1 corresponds to the fact that the refrigerant has not sufficiently absorbed heat from the room and vaporized (cooling the room), so the throttle valve 20 is further throttled, and the temperature signal from the temperature sensor 32 is If higher than the signal, the indoor heat exchanger 21
Means that the refrigerant has sufficiently absorbed heat from the room and vaporized, and if the difference is too large, the throttle valve 2
Control is performed so as to increase the amount of passing refrigerant by increasing the opening degree of 0, thereby enhancing the cooling effect. This control is conventionally employed as a superheat control method, and is controlled so that the low-pressure gas always passes through the passage 23. The throttle valve 20 is a conventional type that acts as a throttle only in the illustrated cooling operation, and is fully opened during heating (during reverse flow).

The mechanism further employed in the present invention will be described. Gas-liquid separator 3 provided in the middle of the outdoor heat exchanger 7
5 through a passage 38 having an on-off valve 36 and a first throttle valve 37 on the way.
9, and the outlet 40 of the heat transfer tube 30 is connected to the passage 24 via the passage 41. The temperature sensors 42 and 43 are the first
It is electrically connected to the throttle valve 37 to form a superheat control mechanism. As a result, the gas refrigerant always passes through the passage 41.

FIG. 2 is a front view of a vertical section of the gas-liquid separator 35.
, A large number of fins 46 are fixed to the outer peripheral surface of the gas-liquid separation U-bend 45 (heat transfer tube), and cooling air is supplied from, for example, an upper fan. Reference numeral 47 denotes a separation tube, and the separation tubes 47 are assembled and connected to the passage 38 via the liquid refrigerant extraction port 34 in FIG. Although the left separation pipe is not shown in FIG. 2, the left separation pipe is similarly connected to the liquid refrigerant extraction port 34 in FIG. 1. 2, the inlet 48 and outlet 49 of the U-bend 45 are connected to the inlet 8 and outlet 9 of FIG. 1 directly or through a plurality of gas-liquid separation U-bends, respectively.

The high-pressure gas-liquid 2 flowing from the inlet 48 in FIG.
The phase refrigerant is cooled by the cooling air to be separated into the liquid phase refrigerant 50 and the gas phase refrigerant 51, and the liquid phase refrigerant 50 is sent to the separation pipe 47 by centrifugal force at the bend portion (curved portion).
All the gas-liquid two-phase refrigerant that has exited the outlet 49 eventually becomes a high-pressure liquid-phase refrigerant and is discharged from the outlet 9 in FIG.

During the cooling operation, the gas-phase refrigerant (high-pressure gas) compressed by the compressor 2 shown in FIG. 1 enters the outdoor heat exchanger 7 through the passage 4, the four-way valve 5, the passage 6, and the inlet 8, where it is cooled. The high-pressure liquid (R32 / R125 rich) enters the cooling receiver 12 through the outlet 9, the passage 11, the throttle valve 10, and the inlet 13 and is supercooled by the heat transfer tube 30 as described later. Pressure reducing device 2 of the machine 18
0 (throttle valve), the heat is removed from the room by the indoor heat exchanger 21 (cooling), and the compressor 2 passes through the passage 23, the four-way valve 5, the passage 24, the accumulator 25, and the passage 26 in a low-pressure gas state. Is returned to the entrance 27.

In the gas-liquid separator 35 in the middle of the outdoor heat exchanger 7, the refrigerant (eg, 10%) liquefied so far is extracted from the liquid refrigerant extraction port 34, and the separated high-pressure liquid (R134) is extracted.
a rich) passes through the passage 38 and the open / close valve 36,
The liquid refrigerant 15 expands at the portion of the throttle valve 37, supercools the liquid refrigerant 15 while passing through the heat transfer tube 30, enters the passage 41 as a low-pressure gas from the outlet 40, and merges with the low-pressure gas in the passage 24. That is, the passage 38, the heat transfer tube 30, and the passage 41 form a cooling bypass circuit.

The solid line frame in FIG. 3 is a normal cycle having no cooling bypass circuit, and the thick white line is a cycle according to the present invention. Also, CP inlet is the compressor inlet, CP outlet is the compressor outlet, outer HEx inlet, outer HEx outlet is the outdoor heat exchanger inlet, outlet, EV input, EV outlet are the decompression device inlet, outlet, and inner HEx outlet is the indoor heat, respectively. Shows the exchanger outlet. L1 in FIG. 3 indicates a pressure drop by the throttle valve 10 in FIG. 1, and L2 indicates a decrease in specific enthalpy due to cooling of the liquid refrigerant 15 in the cooling receiver 12 by flowing the extracted and separated high-pressure liquid to the cooling bypass circuit. In conclusion, according to the present invention, it is understood that the cooling effect is improved by L2.

[0015]

According to the first aspect of the present invention, a part of the high-pressure liquid refrigerant is extracted from the gas-liquid separator 35 in the middle of the outdoor heat exchanger 7, and is expanded by the first throttle valve 37 to cool the refrigerant. 1
Since it is used to cool the liquid refrigerant 15 in the inside 2, the improvement of the cooling performance (for example, 5%) of the entire air conditioner can be expected in addition to the improvement of the heat exchange rate of the outdoor heat exchanger 7. According to the invention of claim 2, the resistance of the passage 11 is increased by the second throttle valve 10, so that the refrigerant is completely liquefied at the outlet of the outdoor heat exchanger 7 during the cooling operation, and the cooling capacity of the cooling receiver is efficiently increased. It is used for supercooling to achieve improved cooling performance.

[Brief description of the drawings]

FIG. 1 is a schematic structural diagram of an air conditioner according to the present invention during a cooling operation.

FIG. 2 is a vertical sectional front view of a gas-liquid separation U-bend in the gas-liquid separator of FIG.

FIG. 3 is a graph showing a relationship between refrigerant pressure and specific enthalpy.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 air conditioner 2 compressor 7 outdoor heat exchanger 9 outlet 10 second throttle valve 12 cooling receiver 20 pressure reducing device 21 indoor heat exchanger 27 inlet 30 heat transfer tube 34 liquid refrigerant extraction port 35 gas-liquid separator 37 first throttle valve 39 inlet Exit 40

Claims (2)

[Claims] 1. An air conditioner in which a refrigerant is circulated by connecting a compressor, an outdoor heat exchanger, a decompression device, and an indoor heat exchanger to extract a liquid refrigerant from a gas-liquid separator in the middle of the outdoor heat exchanger during a cooling operation. That the outlet was connected to the inlet of the heat transfer tube in the cooling receiver provided between the outlet of the outdoor heat exchanger and the pressure reducing device via the first throttle valve, and that the outlet of the heat transfer tube was connected to the inlet of the compressor. A refrigerant supercooling mechanism for air conditioners. 2. The air conditioner according to claim 1, wherein a second throttle valve is provided between an outlet of the outdoor heat exchanger and the cooling receiver to promote supercooling of the refrigerant in the cooling receiver. Cooling mechanism.