JP2003336914A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner capable of preventing a refrigerating capacity from lowering without reducing a refrigerant amount flowing through a refrigerant circuit when a cooling operation is performed at a high ambient temperature. <P>SOLUTION: This air conditioner comprises the refrigerant circuit formed by connecting, in order, a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, an indoor heat exchanger 5, and an accumulator 6. A bypass passage 8 having a relief valve 7 parallel with the expansion valve is connected to both sides of the expansion valve 4. When a pressure difference between both sides of the expansion valve 4 is increased to a specified value or higher during cooling operation, the relief valve is opened to control a part of high pressure liquid refrigerant to bypass the expansion valve to a low pressure side. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an air conditioner, and more particularly, to a refrigerant in an outdoor heat exchanger during a cooling operation at a high outdoor temperature. The present invention relates to a configuration of a refrigerant circuit that can suppress a decrease in the amount of condensate and prevent a decrease in refrigeration capacity. 2. Description of the Related Art As shown in FIG. 2A, a conventional air conditioner includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, and an indoor heat exchanger 5. Are sequentially connected to form a refrigerant circuit. During the cooling operation, the high-temperature and high-pressure refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 3 through the four-way valve 2 and transfers heat to the air flowing around the outdoor heat exchanger 3. Release and condense. The condensed refrigerant expands by passing through the expansion valve 4 and has a low temperature and low pressure, flows into the indoor heat exchanger 5, absorbs heat in the indoor heat exchanger 5, and evaporates. The refrigerant is returned to the compressor 1 through a four-way valve 2. [0003] However, for example, when the outside temperature in the Middle East region is 4
When the above-described air conditioner is operated in an environment exceeding 0 ° C., since high-temperature air flows around the outdoor heat exchanger 3, heat exchange efficiency in the outdoor heat exchanger 3 is reduced, and refrigerant The amount of condensation decreases. As a result, the high-pressure gas-phase refrigerant returns to the compressor 1 via the indoor heat exchanger 5 and the four-way valve 2, and the pressure in the compressor 1 increases. If the pressure rises above a certain level, the high-pressure shell type compressor 1 may be damaged. Therefore, the pressure sensor 22 provided on the discharge pipe side operates to stop the compressor 1 for a predetermined time. It has become. [0006] As means for preventing a pressure increase in the compressor 1, as shown in FIG. 6 (B), between the downstream side of the outdoor heat exchanger 3 and the compressor 1. An injection line 20 having a capillary tube 21 is provided, and the liquid-phase refrigerant flowing out of the outdoor heat exchanger 3 is returned to the compressor 1 by the injection line 20, thereby cooling the compressor 1. , To prevent an abnormal rise in pressure. However, the above-described pressure sensor 2
The method of stopping the compressor 1 by 2 causes discomfort to the user by interrupting the cooling operation, and when the injection pipe 20 is provided, when the cooling operation is performed at a relatively low temperature, Since the liquid-phase refrigerant directly flows into the compressor 1, the compressor 1 may be damaged by liquid compression. SUMMARY OF THE INVENTION In view of the above problems, the present invention prevents a decrease in refrigeration capacity without reducing the amount of refrigerant flowing through a refrigerant circuit during cooling operation at a high outside temperature. It is an object of the present invention to provide an air conditioner that can perform such operations. [0007] In order to solve the above problems, the present invention provides a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, and an accumulator. Are sequentially connected to form a refrigerant circuit,
A bypass including a relief valve is provided in parallel with the expansion valve, and when a pressure difference between both ends of the expansion valve becomes equal to or greater than a predetermined value during a cooling operation, the relief valve is opened and one of the high-pressure liquid refrigerant is released. The part is bypassed to the low pressure side. Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a refrigerant circuit diagram showing an embodiment of an air conditioner according to the present invention. In the figure, a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, an expansion valve 4, an indoor heat exchanger 5, and an accumulator 6 are sequentially connected, while being connected in parallel between both sides of the expansion valve 4. A bypass circuit 8 having a relief valve 7 is provided to constitute a refrigerant circuit. A two-way valve 9 is provided between the expansion valve 4 and the indoor heat exchanger 5.
And the four-way valve 2 are provided with three-way valves 10, respectively.
The outdoor unit and the indoor unit are connected by piping. Next, the flow of the refrigerant in the refrigerant circuit will be described. During the cooling operation, the refrigerant flows in the direction of the solid line arrow in FIG. 1, and the high-temperature and high-pressure refrigerant discharged from the compressor 1 flows into the outdoor heat exchanger 3 via the four-way valve 2, The heat is released and condensed in the heat exchanger 3. The condensed refrigerant passes through the expansion valve 4 and becomes low temperature and low pressure, flows into the indoor heat exchanger 5, absorbs heat in the indoor heat exchanger 5 and evaporates, and the evaporated refrigerant passes through the four-way valve 2 The refrigerant is returned to the compressor 1 through the compressor. The relief valve 7 connected to the bypass passage 8 is closed during a normal cooling and heating operation, but has a pressure difference between both sides of the expansion valve 4 during a cooling operation, that is, the outdoor heat exchanger 3. When the pressure difference between the high-pressure liquid refrigerant that has exited and the low-pressure two-phase refrigerant that has passed through the expansion valve 4 becomes greater than or equal to a predetermined value, it is automatically opened by the operation of a built-in spring. At the time of cooling operation at a high outdoor temperature, high-temperature air flows around the outdoor heat exchanger 3 and the heat exchange efficiency in the outdoor heat exchanger 3 is reduced. Although the pressure of the exchanger 3 increases, when the pressure difference between both sides of the expansion valve 4 becomes equal to or more than a predetermined value, the relief valve 7 is opened as described above. When the relief valve 7 is opened, the high-pressure liquid refrigerant that has exited the outdoor heat exchanger 3 is released to the low-pressure two-phase refrigerant, and the refrigeration capacity is reduced without reducing the amount of refrigerant circulating in the refrigerant circuit. Can be prevented. Further, by connecting one end of the bypass passage 8 to a connection pipe between the expansion valve 4 and the two-way valve 9, the bypass passage 8 receives the influence of vibration generated in the compressor 1. This makes it possible to prevent the occurrence of cracks and the like in the pipes constituting the pipe. As described above, a bypass circuit 8 provided with a relief valve 7 in parallel is provided between both sides of the expansion valve 4 to constitute a refrigerant circuit, and the cooling operation of the expansion valve 4 is performed during a cooling operation at a high outside air temperature. If the pressure difference between both sides exceeds a specified value,
By opening the relief valve 7 and bypassing a part of the high-pressure liquid refrigerant to the low-pressure side, it is possible to prevent a decrease in refrigeration capacity without reducing the amount of refrigerant circulating in the refrigerant circuit, 8 is connected to a connection pipe between the expansion valve 4 and the two-way valve 9,
The influence of the vibration generated in the compressor 1 is reduced by the bypass passage 8.
The air conditioner can prevent the occurrence of cracks in the piping that constitutes the air conditioner. As described above, according to the present invention, a bypass circuit having a relief valve is provided in parallel between both sides of the expansion valve to form a refrigerant circuit, and the refrigerant circuit expands during cooling operation at a high outside air temperature. When the pressure difference between both sides of the valve becomes equal to or more than a predetermined value, the relief valve is opened and a part of the high-pressure liquid refrigerant is bypassed to the low-pressure side, so that the amount of refrigerant circulating in the refrigerant circuit is not reduced, and the refrigeration is performed. It is possible to prevent a decrease in capacity, and by connecting one end of the bypass to the connection pipe between the expansion valve and the two-way valve, the bypass is not affected by the vibration generated in the compressor. Thus, the air conditioner can prevent cracks from occurring in the pipes constituting the air conditioner.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a refrigerant circuit diagram of an air conditioner according to the present invention. FIGS. 2A and 2B are refrigerant circuit diagrams of an air conditioner according to a conventional example. [Description of Signs] 1 Compressor 2 Four-way valve 3 Outdoor heat exchanger 4 Expansion valve 5 Indoor heat exchanger 6 Accumulator 7 Relief valve 8 Bypass path 9 Two-way valve 10 Three-way valve

Claims (1)

Claims 1. A refrigerant circuit is configured by sequentially connecting a compressor, a four-way valve, an outdoor heat exchanger, an expansion valve, an indoor heat exchanger, and an accumulator. In the air conditioner, a bypass including a relief valve is provided in parallel with the expansion valve, and when a pressure difference between both ends of the expansion valve becomes equal to or more than a predetermined value during a cooling operation, the relief valve is opened. An air conditioner characterized in that a part of a high-pressure liquid refrigerant is controlled to be bypassed to a low-pressure side.