JP3723244B2 - Air conditioner - Google Patents

Description

[0001]
[Industrial application fields]
The present invention provides an air equipped with a refrigerant circuit from a compressor discharge port to a compressor intake port through a four-way switching valve, an outdoor heat exchanger, a decompressor, an indoor heat exchanger, a four-way switching valve, and an accumulator. It is about a harmony machine.
[0002]
[Prior art]
FIG. 11 is a refrigerant circuit diagram of a conventional multi-chamber air conditioner disclosed in, for example, Japanese Utility Model Publication No. 55-28993, in which (1) is a compressor, (1a) is a discharge port thereof, ( 1b) is an inlet, (2) is a four-way selector valve, (3) is an outdoor heat exchanger, (4) is a liquid side branch pipe, (5a) (5b) (5c) are electronic expansion valves, (6a) (6b) and (6c) are indoor side heat exchangers, (7) is a gas side branch pipe, and (8) is an accumulator.
[0003]
Next, the flow of the refrigerant during cooling of the refrigerant circuit will be described. The high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the four-way switching valve (2) and exchanges heat with outdoor air in the outdoor heat exchanger (3) to release heat. As a result, it is condensed into a gas-liquid two-phase or liquid refrigerant at room temperature and high pressure, branched for each indoor unit by the liquid side branch pipe (4), and depressurized by the respective electronic expansion valves (5a) (5b) (5c). Then, it becomes a complete gas-liquid two-phase and enters the indoor side heat exchanger (6a) (6b) (6c) of each indoor unit. Each indoor heat exchanger (6a) (6b) (6c) exchanges heat with the indoor air, absorbs the heat, evaporates, and becomes a low-temperature, low-pressure superheated gas or gas-liquid two-phase (7) Merge and pass through the four-way selector valve (2) into the accumulator (8). The liquid refrigerant is separated by the accumulator (8) and sucked into the compressor (1) from the suction port (1b). This cycle is repeated thereafter.
[0004]
During the heating operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the four-way selector valve (2) and passes through the gas side branch pipe (7) for each indoor unit. Into the indoor heat exchanger (6a) (6b) (6c) of each indoor unit. Each indoor-side heat exchanger (6a) (6b) (6c) exchanges heat with the indoor air and releases heat, condensing into a gas-liquid two-phase or liquid refrigerant at room temperature and high pressure, and each electronic expansion valve (5a ) (5b) (5c), the pressure is reduced to a complete gas-liquid two-phase phase, and the liquid side branch pipe (4) joins to enter the outdoor heat exchanger (3). The outdoor heat exchanger (3) exchanges heat with the outdoor air and absorbs the heat, evaporates into a low-temperature and low-pressure superheated gas or gas-liquid two-phase, passes through the four-way selector valve (2), and enters the accumulator (8). enter. The liquid refrigerant is separated by the accumulator (8) and sucked into the compressor (1) from the suction port (1b). This cycle is repeated thereafter.
[0005]
[Problems to be solved by the invention]
In the refrigerant circuit configured as described above, it is usually preferable that only the liquid refrigerant flows into the expansion valves such as the electronic expansion valves (5a), (5b), and (5c). If there is a large pressure loss due to pipe flow resistance in the outer heat exchanger (3), or if the outdoor heat exchanger (3) is limited in size and sufficient heat exchange performance cannot be obtained, Until the operation state changes and the refrigeration cycle stabilizes, the refrigerant that flows into the electronic expansion valves (5a), (5b), and (5c) cannot be properly cooled in the outdoor heat exchanger (3). It may become. For this reason, refrigerant distribution to the indoor heat exchangers (6a), (6b), and (6c) is poor by adjusting the opening of the electronic expansion valves (5a), (5b), and (5c). The refrigeration capacity of the machine becomes unstable, and uncomfortable refrigerant flow noise occurs when the refrigerant passing through the electronic expansion valves (5a), (5b), and (5c) is in a gas-liquid two phase.
[0006]
In addition, during the heating operation, the outdoor heat exchanger (3) gasifies during the compressor operation, and there are many refrigerants that become liquid from the gas state while the compressor (1) is stopped. When passing through the accumulator (8) from the exchanger (3) through the four-way selector valve (2), the liquid refrigerant cannot be completely separated, and the compressor (1) is inhaled with a lot of liquid refrigerant. Since liquid compression is performed, there is a problem that the load on the compressor (1) is increased and the life is shortened.
[0007]
The present invention has been made to solve the above-described problems. During cooling operation, complete liquid refrigerant flows into the expansion valve from the liquid side branch pipe, and refrigerant distribution to a plurality of indoor heat exchangers is performed. An object of the present invention is to obtain an air conditioner that is stable and does not generate refrigerant flow noise when refrigerant passes through an expansion valve.
[0008]
It is another object of the present invention to provide an air conditioner in which liquid refrigerant is not sucked into the compressor at the time of restarting the heating operation and the life of the compressor can be increased.
[0009]
  The air conditioner according to the present invention includes a compressor discharge port, a four-way switching valve, an outdoor heat exchanger, a liquid side branch pipe, a plurality of expansion valves, a plurality of indoor side heat exchangers, a gas side branch pipe, In a multi-chamber type air conditioner equipped with a four-way switching valve, and a refrigerant circuit leading to the compressor inlet through the accumulator,
A refrigerant heat exchanger that exchanges heat between the refrigerant in the refrigerant pipes between the outdoor heat exchanger and the refrigerant pipe between the liquid side branch pipes and the refrigerant pipe between the accumulator and the compressor suction port. As well as,
  The high pressure side to the low pressure side between the liquid side branch pipe side from the refrigerant heat exchanger of the refrigerant pipe between the outdoor heat exchanger and the liquid side branch pipe and between the refrigerant pipes between the accumulator and the refrigerant heat exchanger. Is provided with a bypass circuit with a throttle to return the saturated gas to.
[0010]
  The air conditioner according to the present invention includes a refrigerant heat exchanger, an outdoor heat exchanger, an outer pipe through which refrigerant flows between the liquid side branch pipes, a four-way switching valve, between accumulators, or an accumulator and a compressor intake. It has a double-pipe structure with an inner pipe that flows refrigerant between the mouths..
[0011]
  In the air conditioner according to the present invention, the refrigerant flow directions in the outer pipe and the inner pipe of the refrigerant heat exchanger are reversed..
[0014]
[Action]
In this invention, the high-temperature and high-pressure refrigerant condensed in the outdoor heat exchanger during cooling and the low-temperature and low-pressure refrigerant from the four-way switching valve to the accumulator or from the accumulator to the compressor inlet are heat-exchanged, The refrigerant is cooled and flows into the expansion valve through the liquid side branch pipe as a complete liquid refrigerant, so that the refrigerant distribution to the plurality of indoor heat exchangers is stabilized and the refrigerant noise generated in the expansion valve is reduced. . And since the refrigerant | coolant of a low voltage | pressure side is heated and becomes superheated gas, a liquid refrigerant is never suck | inhaled by a compressor at all.
[0015]
In addition, the superheat degree of the low-pressure side refrigerant due to the heat exchange between both the high-pressure side and low-pressure side refrigerant in the refrigerant heat exchanger is prevented by returning the saturated gas from the high-pressure side to the low-pressure side in the bypass circuit with a throttle.
Furthermore, since some saturated gas of the refrigerant further cooled by the refrigerant heat exchanger is returned to the low pressure side by the bypass circuit with throttle, the amount of refrigerant bypassed can be further reduced.
[0016]
In addition, since the refrigerant heat exchanger has a double-pipe structure of an outer pipe through which the high-pressure side high-temperature refrigerant flows and an inner pipe through which the low-pressure side low-temperature refrigerant flows, the high-pressure side high-temperature refrigerant is the low-temperature refrigerant in the inner pipe and the air around the outer pipe. As a result, the high-pressure side refrigerant is further subcooled.
Furthermore, since the refrigerant flow directions in the outer pipe and the inner pipe are reversed, the amount of heat exchange is further increased.
[0017]
In addition, when heating operation is started, by opening an electromagnetic valve or an electronic expansion valve of the bypass circuit from the compressor discharge port to the compressor suction port, the heated gas discharged from the compressor is sucked into the compressor, and the outdoor heat The liquid refrigerant that is liquefied by the exchanger and sucked into the compressor without being separated by the accumulator is gasified, and the load on the compressor is reduced.
[0018]
【Example】
Example 1.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of the first embodiment, where (1) is a compressor, (1a) is a discharge port thereof, (1b) is a suction port, (2) is a four-way selector valve, (3) Is an outdoor heat exchanger, (4) is a liquid side branch pipe, (5a) (5b) (5c) are electronic expansion valves, (6a) (6b) (6c) are indoor heat exchangers, (7) is The gas side branch pipe (8) is an accumulator, and the above is the same as the conventional example shown in FIG. (9) is the refrigerant pipe between the outdoor heat exchanger (3) and the liquid side branch pipe (4), (10) is the refrigerant pipe between the four-way selector valve (2) and the accumulator (8), and (11) is these Refrigerant heat exchanger that performs heat exchange of refrigerant in both refrigerant pipes (9) and (10), (12) is a liquid side branch pipe (4) side of the refrigerant heat exchanger (11) of the refrigerant pipe (9), It is a bypass circuit with a capillary throttle provided between the refrigerant pipe (10).
[0019]
Next, the refrigerant flow during cooling of the refrigerant circuit of this embodiment will be described. The high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the four-way switching valve (2) and exchanges heat with outdoor air in the outdoor heat exchanger (3) to release heat. As a result, it condenses into a gas-liquid two-phase or liquid refrigerant at room temperature and high pressure, and is cooled and completely liquefied by heat exchange with the low-temperature and low-pressure gas refrigerant in the refrigerant pipe (10) by the refrigerant heat exchanger (11). Are branched for each indoor unit by the liquid side branch pipe (4), depressurized by the respective electronic expansion valves (5a), (5b) and (5c) to become a complete gas-liquid two-phase, the indoor side of each indoor unit The heat exchanger (6a) (6b) (6c) is entered.
[0020]
In each indoor heat exchanger (6a) (6b) (6c), the gas-liquid two-phase refrigerant exchanges heat with the indoor air, absorbs heat and evaporates, and becomes a low-temperature and low-pressure superheated gas or gas-liquid two-phase gas. It merges in the side branch pipe (7), passes through the four-way switching valve (2), and is exchanged with the high-pressure liquid refrigerant in the refrigerant pipe (9) by the refrigerant heat exchanger (11), heated, further gasified and accumulator (8 )to go into. The liquid refrigerant is separated by the accumulator (8) and sucked into the compressor (1) from the suction port (1b). This cycle is repeated thereafter.
[0021]
In addition, a part of the liquid refrigerant from the outdoor heat exchanger (3) to the refrigerant pipe (9) and the refrigerant heat exchanger (11) becomes saturated gas in the bypass circuit (12) with a throttle and enters the refrigerant pipe (10). Bypassing, the degree of superheat of the low-pressure gas refrigerant in the refrigerant pipe (10) is prevented from excessively rising due to heat exchange by the refrigerant heat exchanger (11), and the appropriate superheated gas passes through the accumulator (8). It is sucked into the compressor (1).
[0022]
During the heating operation, the high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the four-way selector valve (2) and passes through the gas side branch pipe (7) for each indoor unit. Into the indoor heat exchanger (6a) (6b) (6c) of each indoor unit. Each indoor-side heat exchanger (6a) (6b) (6c) exchanges heat with the indoor air and releases heat, condensing into a gas-liquid two-phase or liquid refrigerant at room temperature and high pressure, and each electronic expansion valve (5a ) (5b) (5c) is reduced to a complete gas-liquid two-phase and merges in the liquid side branch pipe (4), passes through the refrigerant heat exchanger (11) and refrigerant pipe (9), and the outdoor heat exchanger (3 )to go into. Heat is exchanged with outdoor air in the outdoor heat exchanger (3) to absorb heat and evaporate into a low-temperature and low-pressure superheated gas or gas-liquid two-phase, passing through the four-way selector valve (2) and the refrigerant piping (10) Then, the refrigerant passes through the refrigerant heat exchanger (11) and enters the accumulator (8). The liquid refrigerant is separated by the accumulator (8) and sucked into the compressor (1) from the suction port (1b).
[0023]
At this time, the refrigerant heat exchanger (11) performs heat exchange between the low-temperature and low-pressure refrigerant in the refrigerant pipe (9) and the low-temperature and low-pressure refrigerant in the refrigerant pipe (10). There is little difference in temperature and very effective heat exchange is not performed, and there is no need to provide a check valve or the like that bypasses the refrigerant heat exchanger (11) particularly during heating. In addition, since there is no pressure difference between both ends of the bypass circuit (12) with restriction, it does not operate effectively during heating. However, since the refrigerant heat exchanger (11) and the bypass bypass circuit (12) are not required during heating, a check valve is provided in the refrigerant heat exchanger (11) installation part of the refrigerant pipe (9) to remove them during heating. It may be bypassed.
[0024]
As described above, in this embodiment, the refrigerant flowing into the electronic expansion valves (5a), (5b), and (5c) by the refrigerant heat exchanger (11) during cooling is converted into the indoor heat exchangers (6a), (6b), (6c). The refrigerant is cooled and completely liquefied by the low-temperature and low-pressure refrigerant that has exited the refrigerant), so that the refrigerant distribution to the plurality of indoor heat exchangers (6a), (6b), and (6c) is stabilized, and Refrigerant noise generated in the expansion valves (5a) (5b) (5c) is reduced. Moreover, an excessive increase in the degree of superheat of the low-pressure gas refrigerant due to the heat exchange is prevented by bypassing the saturated gas by the bypass circuit with throttle (12).
[0025]
Example 2
In Example 1, the refrigerant heat exchanger (11) is connected between the outdoor heat exchanger (3), the refrigerant pipe (9) between the liquid side branch pipe (4), the four-way switching valve (2), and the accumulator (8). Although provided between the refrigerant pipe (10), it may be provided between the refrigerant pipe (9) and the refrigerant pipe (13) between the accumulator (8) and the compressor inlet (1b). FIG. 2 is a refrigerant circuit diagram of Example 2 in this case.
[0026]
In the figure, (1) is a compressor, (1a) is its discharge port, (1b) is a suction port, (2) is a four-way switching valve, (3) is an outdoor heat exchanger, (4) is a liquid side Branch pipe, (5a) (5b) (5c) is an electronic expansion valve, (6a) (6b) (6c) is an indoor heat exchanger, (7) is a gas branch pipe, (8) is an accumulator, (9 ) Is the refrigerant pipe between the outdoor heat exchanger (3) and the liquid side branch pipe (4), (10) is the refrigerant pipe between the four-way selector valve (2) and the accumulator (8), and (13) is the accumulator (8 ) And the compressor inlet (1b), (11) is a refrigerant heat exchanger for exchanging heat in the refrigerant pipes (9) and (13), and (12) is a refrigerant in the refrigerant pipe (9). A bypass circuit with a restriction such as a capillary tube provided between the liquid side branch pipe (4) side of the heat exchanger (11) and the refrigerant pipe (13).
[0027]
Next, the refrigerant flow during cooling of the refrigerant circuit of this embodiment will be described. The high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the four-way switching valve (2) and exchanges heat with outdoor air in the outdoor heat exchanger (3) to release heat. As a result, it condenses into a gas-liquid two-phase or liquid refrigerant at room temperature and high pressure, and is cooled by the heat exchange with the low-temperature and low-pressure gas refrigerant in the refrigerant pipe (13) by the refrigerant heat exchanger (11) to be completely liquefied. Are branched for each indoor unit by the liquid side branch pipe (4), depressurized by the respective electronic expansion valves (5a), (5b) and (5c) to become a complete gas-liquid two-phase, the indoor side of each indoor unit The heat exchanger (6a) (6b) (6c) is entered.
[0028]
In each indoor heat exchanger (6a) (6b) (6c), the gas-liquid two-phase refrigerant exchanges heat with the indoor air, absorbs heat and evaporates, and becomes a low-temperature and low-pressure superheated gas or gas-liquid two-phase gas. Merges at the side branch pipe (7), passes through the four-way switching valve (2), and enters the accumulator (8). Even if the liquid refrigerant is separated by the accumulator (8) and the liquid refrigerant is not completely separated by the accumulator (8), the refrigerant heat exchanger (11) exchanges heat with the high-pressure liquid refrigerant in the refrigerant pipe (9). It is heated, completely gasified, and sucked into the compressor (1) through the suction port (1b). This cycle is repeated thereafter.
[0029]
In addition, a part of the liquid refrigerant from the outdoor heat exchanger (3) to the refrigerant pipe (9) and the refrigerant heat exchanger (11) becomes saturated gas in the bypass circuit (12) with a throttle and enters the refrigerant pipe (10). Bypassing, the degree of superheat of the low-pressure gas refrigerant in the refrigerant pipe (10) is prevented from excessively rising due to heat exchange by the refrigerant heat exchanger (11), and appropriate superheated gas is sucked into the compressor (1). Is done.
[0030]
As described above, also in this embodiment, the refrigerant flowing into the electronic expansion valves (5a), (5b), and (5c) by the refrigerant heat exchanger (11) during cooling is converted into the indoor side heat exchangers (6a), (6b), (6c). The refrigerant is cooled and completely liquefied by the low-temperature and low-pressure refrigerant that has exited the refrigerant), so that the refrigerant distribution to the plurality of indoor heat exchangers (6a), (6b), and (6c) is stabilized, and Refrigerant noise generated in the expansion valves (5a) (5b) (5c) is reduced. Moreover, an excessive increase in the degree of superheat of the low-pressure gas refrigerant due to the heat exchange is prevented by bypassing the saturated gas by the bypass circuit with throttle (12). Further, even if the liquid refrigerant is not completely separated by the accumulator (8), it is completely gasified by heat exchange by the refrigerant heat exchanger (11) and sucked into the compressor (1).
[0031]
In each of the above embodiments, a capillary tube is used for the bypass bypass circuit (12). However, equivalent control can be performed by using a mechanical expansion valve or an electronic expansion valve.
[0032]
3 and 4 show an example of the refrigerant heat exchanger (11) used in the first embodiment, FIG. 3 is a perspective view, and FIG. 4 is a longitudinal sectional view. In the figure, (11) is a refrigerant heat exchanger, an outdoor heat exchanger (3), an outer pipe (11a) communicating with the refrigerant pipe (9) between the liquid side branch pipe (4), and a four-way switching valve ( 2) It has a double pipe structure with an inner pipe (11b) communicating with the refrigerant pipe (10) between the accumulators (8). The refrigerant flow direction in the outer pipe (11a) and the refrigerant flow direction in the inner pipe (11b) are opposite to each other.
[0033]
Therefore, the structure is simple and can be manufactured at low cost, and the entire inner pipe (11b) is covered with a high-temperature and high-pressure refrigerant, so that a large heat transfer area is taken and efficient heat exchange is performed, and the high-temperature and high-pressure in the outer pipe (11a) is achieved. Since the refrigerant exchanges heat between the low-temperature refrigerant in the inner pipe (11b) and the air around the outer pipe (11a), the high-pressure refrigerant is further subcooled. Further, since the flow of the refrigerant to be heat exchanged is opposite, the most efficient counter flow heat exchange is performed.
Of course, the refrigerant heat exchanger (11) having this structure can obtain the same effect even when used in the second embodiment.
[0034]
Reference example 1.
  FIG. 5 shows the present invention.Reference example 1FIG. In the figure, (1) is a compressor, (1a) is its discharge port, (1b) is a suction port, (2) is a four-way switching valve, (3) is an outdoor heat exchanger, (4) is a liquid side Branch pipe, (5a) (5b) (5c) is an electronic expansion valve, (6a) (6b) (6c) is an indoor heat exchanger, (7) is a gas branch pipe, (8) is an accumulator, (9 ) Is the refrigerant pipe between the outdoor heat exchanger (3) and the liquid side branch pipe (4), (10) is the refrigerant pipe between the four-way selector valve (2) and the accumulator (8), and (11) is the refrigerant heat exchange. (13a) is a refrigerant pipe between the accumulator (8) and the refrigerant heat exchanger (11), (13b) is a refrigerant pipe between the refrigerant heat exchanger (11) and the compressor inlet (1b), (14) Is a refrigerant pipe between the compressor discharge port (1a) and the four-way selector valve (2), and the above is substantially the same as in the second embodiment. (15) is a bypass circuit between the refrigerant pipe (14) and the refrigerant pipe (13a), and (16) is an electromagnetic valve provided in the bypass circuit (15).
[0035]
Next, the refrigerant flow during cooling of the refrigerant circuit of this embodiment will be described. Since the solenoid valve (16) is closed during cooling, the operation during cooling is substantially the same as in the second embodiment. That is, the high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the four-way switching valve (2) and is heat-exchanged with outdoor air by the outdoor heat exchanger (3). Is condensed into a gas-liquid two-phase or liquid refrigerant at room temperature and pressure, and is cooled by the heat exchange with the low-temperature and low-pressure gas refrigerant in the refrigerant pipe (13) by the refrigerant heat exchanger (11). It is liquefied and branched for each indoor unit by the liquid side branch pipe (4), decompressed by the respective electronic expansion valves (5a), (5b), and (5c) to become a complete gas-liquid two-phase, It enters the indoor heat exchanger (6a) (6b) (6c).
[0036]
In each indoor heat exchanger (6a) (6b) (6c), the gas-liquid two-phase refrigerant exchanges heat with the indoor air, absorbs heat and evaporates, and becomes a low-temperature and low-pressure superheated gas or gas-liquid two-phase gas. Merges at the side branch pipe (7), passes through the four-way switching valve (2), and enters the accumulator (8). Even if the liquid refrigerant is separated by the accumulator (8) and the liquid refrigerant is not completely separated by the accumulator (8), the refrigerant heat exchanger (11) exchanges heat with the high-pressure liquid refrigerant in the refrigerant pipe (9). It is heated, completely gasified, and sucked into the compressor (1) through the suction port (1b). This cycle is repeated thereafter.
[0037]
The electromagnetic valve (16) is opened for a predetermined time at the start of heating operation. Thereby, a part of the high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the bypass circuit (15) and is sucked into the compressor (1) from the suction port (1b). . Therefore, the refrigerant liquefied in the compressor (1) or the outdoor heat exchanger (3) while the compressor (1) is not operating is liquefied by the accumulator (8) without being sufficiently separated. The liquid refrigerant sucked into the machine (1) is gasified by the high-temperature gas refrigerant from the bypass circuit (15), and the load on the compressor (1) at the start of the heating operation is significantly reduced. When this operation is continued for a predetermined time and all the refrigerant sucked into the compressor (1) becomes a gas refrigerant, the electromagnetic valve (16) is closed and a normal heating operation is started.
[0038]
That is, the high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the four-way switching valve (2) and is branched for each indoor unit by the gas side branch pipe (7). It enters the indoor heat exchanger (6a) (6b) (6c) of each indoor unit. Each indoor-side heat exchanger (6a) (6b) (6c) exchanges heat with the indoor air and releases heat, condensing into a gas-liquid two-phase or liquid refrigerant at room temperature and high pressure, and each electronic expansion valve (5a ) (5b) (5c) is reduced to a complete gas-liquid two-phase and merges in the liquid side branch pipe (4), passes through the refrigerant heat exchanger (11) and refrigerant pipe (9), and the outdoor heat exchanger (3 )to go into. By exchanging heat with outdoor air in the outdoor heat exchanger (3) and absorbing heat, it evaporates into a low-temperature and low-pressure superheated gas or gas-liquid two-phase, and the four-way switching valve (2) and refrigerant pipe (10) are connected. Enter the street accumulator (8). The liquid refrigerant is separated by the accumulator (8), passes through the refrigerant heat exchanger (11), and is sucked into the compressor (1) from the suction port (1b).
[0039]
Reference example 2.
  Reference example 1The bypass circuit (15) is provided between the refrigerant pipe (14) and the refrigerant pipe (13a), but may be provided between the refrigerant pipe (14) and the refrigerant pipe (13a). Figure 6 showsReference example 2FIG. In the figure, (1) is a compressor, (1a) is its discharge port, (1b) is a suction port, (2) is a four-way switching valve, (3) is an outdoor heat exchanger, (4) is a liquid side Branch pipe, (5a) (5b) (5c) is an electronic expansion valve, (6a) (6b) (6c) is an indoor heat exchanger, (7) is a gas branch pipe, (8) is an accumulator, (9 ) Is the refrigerant pipe between the outdoor heat exchanger (3) and the liquid side branch pipe (4), (10) is the refrigerant pipe between the four-way selector valve (2) and the accumulator (8), and (11) is the refrigerant heat exchange. (13a) is a refrigerant pipe between the accumulator (8) and the refrigerant heat exchanger (11), (13b) is a refrigerant pipe between the refrigerant heat exchanger (11) and the compressor inlet (1b), (14) Is a refrigerant pipe between the compressor discharge port (1a) and the four-way selector valve (2), (15) is a bypass circuit between the refrigerant pipe (14) and the refrigerant pipe (13b), and (16) is a bypass circuit (15 ) Solenoid valve provided inside.
  The operation of this embodiment isReference example 1The description is omitted because it is substantially the same as.
[0040]
Reference example 3.
  Reference example 1In, it has a plurality of electronic expansion valves (5a) (5b) (5c), a plurality of indoor heat exchangers (6a) (6b) (6c), a liquid side branch pipe (4) and a gas side branch pipe (7) The multi-room air conditioner has been described, but the effect of providing the bypass circuit (15) is the same even if the indoor heat exchanger is an air conditioner using one refrigerant circuit. Figure 7 showsReference example 3FIG.
[0041]
In the figure, (1) is a compressor, (1a) is its discharge port, (1b) is a suction port, (2) is a four-way switching valve, (3) is an outdoor heat exchanger, (5) is an electronic expansion Valve, (6) indoor heat exchanger, (8) accumulator, (9) refrigerant piping between outdoor heat exchanger (3) and electronic expansion valve (5), (10) four-way switching valve ( 2) and refrigerant pipe between accumulator (8), (13) refrigerant pipe between accumulator (8) and compressor inlet (1b), (14) compressor outlet (1a) and four-way switching valve (2 ) Refrigerant piping, (15) is a bypass circuit, and (16) is a solenoid valve.
[0042]
Next, the refrigerant flow during cooling of the refrigerant circuit of this embodiment will be described. The electromagnetic valve (16) is closed during cooling. The high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the four-way switching valve (2) and exchanges heat with outdoor air in the outdoor heat exchanger (3) to release heat. As a result, it condenses into a gas-liquid two-phase or liquid refrigerant at room temperature and high pressure, and is depressurized by the electronic expansion valve (5) to become a complete gas-liquid two-phase and enters the indoor heat exchanger (6).
[0043]
The electromagnetic valve (16) is opened for a predetermined time at the start of heating operation. Thereby, a part of the high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the bypass circuit (15) and is sucked into the compressor (1) from the suction port (1b). . Therefore, the refrigerant liquefied in the compressor (1) or the outdoor heat exchanger (3) while the compressor (1) is not operating is liquefied by the accumulator (8) without being sufficiently separated. The liquid refrigerant sucked into the machine (1) is gasified by the high-temperature gas refrigerant from the bypass circuit (15), and the load on the compressor (1) at the start of the heating operation is significantly reduced. When this operation is continued for a predetermined time and all the refrigerant sucked into the compressor (1) becomes a gas refrigerant, the electromagnetic valve (16) is closed and a normal heating operation is started.
[0044]
That is, the high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the four-way switching valve (2) and enters the indoor heat exchanger (6). By exchanging heat with indoor air in the indoor heat exchanger (6) and releasing heat, it condenses to become a gas-liquid two-phase or liquid refrigerant at room temperature and high pressure, and is decompressed by the electronic expansion valve (5) to complete gas-liquid two-phase. It becomes a phase, merges at the liquid side branch pipe (4), passes through the refrigerant heat exchanger (11) and the refrigerant pipe (9), and enters the outdoor heat exchanger (3). By exchanging heat with outdoor air in the outdoor heat exchanger (3) and absorbing heat, it evaporates into a low-temperature and low-pressure superheated gas or gas-liquid two-phase, and the four-way switching valve (2) and refrigerant pipe (10) are connected. Enter the street accumulator (8). The liquid refrigerant is separated by the accumulator (8), passes through the refrigerant pipe (13), and is sucked into the compressor (1) from the suction port (1b).
[0045]
  Reference example 3The refrigerant heat exchanger (11) is not provided because there is no need to consider refrigerant distribution by multiple electronic expansion valves (5a) (5b) (5c), but the refrigerant noise of the electronic expansion valve (5) is reduced. Therefore, the refrigerant heat exchanger (11) may be provided between the refrigerant pipes (9) and (10) or between the refrigerant pipes (9) and (13).
  Also,Reference Examples 1-3In FIG. 1, the bypass circuit (15) is opened and closed by the electromagnetic valve (16). However, noise caused by opening and closing of the bypass circuit (15) can be reduced by slowly opening and closing the electronic expansion valve.Reference Examples 4-6Is an example of this case.
[0046]
Reference example 4.
  Figure 8Reference example 4FIG. In the figure, (1) is a compressor, (1a) is its discharge port, (1b) is a suction port, (2) is a four-way switching valve, (3) is an outdoor heat exchanger, (4) is a liquid side Branch pipe, (5a) (5b) (5c) is an electronic expansion valve, (6a) (6b) (6c) is an indoor heat exchanger, (7) is a gas branch pipe, (8) is an accumulator, (9 ) Is the refrigerant pipe between the outdoor heat exchanger (3) and the liquid side branch pipe (4), (10) is the refrigerant pipe between the four-way selector valve (2) and the accumulator (8), and (11) is the refrigerant heat exchange. (13a) is a refrigerant pipe between the accumulator (8) and the refrigerant heat exchanger (11), (13b) is a refrigerant pipe between the refrigerant heat exchanger (11) and the compressor inlet (1b), (14) Is a refrigerant pipe between the compressor discharge port (1a) and the four-way selector valve (2), (15) is a bypass circuit between the refrigerant pipe (14) and the refrigerant pipe (13a), and (17) is a bypass circuit (15 ) Is an electronic expansion valve provided inside.
[0047]
  The operation during cooling and normal heating in this embodiment is as follows.Reference example 3Since this is the same as the above, the description is omitted, and the operation at the start of heating will be described.
  At the start of heating operation, the electronic expansion valve (17) is controlled and slowly opened. As a result, part of the high-temperature and high-pressure gas refrigerant compressed by the compressor (1) and discharged from the discharge port (1a) passes through the bypass circuit (15) and generates noise from the suction port (1b) to the compressor (1). Inhaled slowly without Therefore, the refrigerant liquefied in the compressor (1) or the outdoor heat exchanger (3), etc. during the shutdown of the compressor (1) is liquefied and compressed without being sufficiently separated by the accumulator (8). The liquid refrigerant sucked into the machine (1) is gasified by the high-temperature gas refrigerant from the bypass circuit (15), and the load on the compressor (1) at the start of the heating operation is significantly reduced. When this operation is continued for a predetermined time and all the refrigerant sucked into the compressor (1) becomes a gas refrigerant, the electronic expansion valve (17) is slowly closed and a normal heating operation is started.
[0048]
Reference Example 5.
  Figure 9Reference Example 5FIG. In the figure, (1) is a compressor, (1a) is its discharge port, (1b) is a suction port, (2) is a four-way switching valve, (3) is an outdoor heat exchanger, (4) is a liquid side Branch pipe, (5a) (5b) (5c) is an electronic expansion valve, (6a) (6b) (6c) is an indoor heat exchanger, (7) is a gas branch pipe, (8) is an accumulator, (9 ) Is the refrigerant pipe between the outdoor heat exchanger (3) and the liquid side branch pipe (4), (10) is the refrigerant pipe between the four-way selector valve (2) and the accumulator (8), and (11) is the refrigerant heat exchange. (13a) is a refrigerant pipe between the accumulator (8) and the refrigerant heat exchanger (11), (13b) is a refrigerant pipe between the refrigerant heat exchanger (11) and the compressor inlet (1b), (14) Is a refrigerant pipe between the compressor discharge port (1a) and the four-way selector valve (2), (15) is a bypass circuit between the refrigerant pipe (14) and the refrigerant pipe (13b), and (17) is a bypass circuit (15 ) Is an electronic expansion valve provided inside.
  The operation of this embodiment isReference example 4The description is omitted because it is substantially the same as.
[0049]
Reference Example 6.
  FIG.Reference Example 6FIG. In the figure, (1) is a compressor, (1a) is its discharge port, (1b) is a suction port, (2) is a four-way switching valve, (3) is an outdoor heat exchanger, (5) is an electronic expansion Valve, (6) indoor heat exchanger, (8) accumulator, (9) refrigerant piping between outdoor heat exchanger (3) and electronic expansion valve (5), (10) four-way switching valve ( 2) and refrigerant pipe between accumulator (8), (13) refrigerant pipe between accumulator (8) and compressor inlet (1b), (14) compressor outlet (1a) and four-way switching valve (2 ) Refrigerant piping, (15) is a bypass circuit, and (17) is an electronic expansion valve provided in the bypass circuit (15).
  The operation of the electronic expansion valve (17) of this embodiment isReference example 4And the other parts areReference example 3The explanation is omitted because it is the same as.
[0050]
【The invention's effect】
In this invention, the high-temperature and high-pressure refrigerant condensed in the outdoor heat exchanger during cooling and the low-temperature and low-pressure refrigerant from the four-way switching valve to the accumulator or from the accumulator to the compressor inlet are heat-exchanged, Since the refrigerant is cooled and flows into the expansion valve through the liquid side branch pipe as a complete liquid refrigerant, the refrigerant distribution to the plurality of indoor heat exchangers is stabilized, and the refrigerant sound generated in the expansion valve is reduced. Since the low-pressure side refrigerant is heated to become superheated gas and sucked into the compressor, liquid compression can be prevented.
[0051]
In addition, the superheat degree of the low-pressure side refrigerant due to the heat exchange of both refrigerants on the high-pressure side and low-pressure side in the refrigerant heat exchanger is prevented by returning saturated gas from the high-pressure side to the low-pressure side in the bypass circuit with restriction, and always The compressor has an effect of sucking an appropriate superheated gas into the compressor.
[0052]
Furthermore, since a part of the saturated gas of the refrigerant further cooled by the refrigerant heat exchanger is returned to the low pressure side by the bypass circuit with the throttle, the amount of refrigerant to be bypassed can be reduced.
[0053]
In addition, since the refrigerant heat exchanger has a double-pipe structure of an outer pipe through which the high-pressure side high-temperature refrigerant flows and an inner pipe through which the low-pressure side low-temperature refrigerant flows, the high-pressure side high-temperature refrigerant includes As a result, the high-pressure side refrigerant is further subcooled.
[0054]
Furthermore, since the refrigerant flow directions in the outer tube and the inner tube are reversed, the heat exchange amount is further increased.
[0055]
In addition, since a bypass circuit that is opened and closed by a solenoid valve is provided between the compressor discharge port and the compressor suction port, the heating gas discharged from the compressor is opened by opening this solenoid valve when heating operation starts. Liquid refrigerant that is sucked into the compressor, liquefied by the outdoor heat exchanger, etc., and sucked into the compressor without being separated by the accumulator is gasified, reducing the load on the compressor and extending the life of the compressor. It is what you have.
[0056]
In addition, since the bypass circuit is opened and closed by the electronic expansion valve at the start of heating operation, the load on the compressor is reduced, the life of the compressor is extended, and the electronic expansion valve is opened and closed slowly to open and close the valve. The noise value is reduced.
[Brief description of the drawings]
FIG. 1 is a refrigerant circuit diagram of Example 1. FIG.
2 is a refrigerant circuit diagram of Example 2. FIG.
3 is a perspective view of a refrigerant heat exchanger used in Embodiment 1. FIG.
4 is a longitudinal sectional view of a refrigerant heat exchanger used in Example 1. FIG.
5 is a refrigerant circuit diagram of Reference Example 1. FIG.
6 is a refrigerant circuit diagram of Reference Example 2. FIG.
7 is a refrigerant circuit diagram of Reference Example 3. FIG.
FIG. 8 is a refrigerant circuit diagram of Reference Example 4.
9 is a refrigerant circuit diagram of Reference Example 5. FIG.
10 is a refrigerant circuit diagram of Reference Example 6. FIG.
FIG. 11 is a refrigerant circuit diagram of a conventional multi-room air conditioner.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Compressor, 1a Discharge port, 1b Inlet port, 2 Four-way switching valve, 3 Outdoor heat exchanger, 4 Liquid side branch pipe, 5, 5a, 5b, 5c Electronic expansion valve, 6, 6a, 6b, 6c Indoor side Heat exchanger, 7 gas side branch pipe, 8 accumulator, 9, 10, 13, 14 refrigerant piping, 11 refrigerant heat exchanger, 12 bypass circuit with throttle, 15 bypass circuit, 16 solenoid valve, 17 electronic expansion valve.

Claims (3)

Compressor from compressor outlet to four-way switching valve, outdoor heat exchanger, liquid side branch pipe, multiple expansion valves, multiple indoor heat exchangers, gas side branch pipe, four-way switching valve, and accumulator In a multi-chamber air conditioner equipped with a refrigerant circuit leading to the inlet,
The outdoor heat exchanger, a refrigerant pipe between the liquid side branch pipes, the accumulator, between a refrigerant pipe between the compressor inlet, a refrigerant heat exchanger for exchanging heat of the coolant of both the refrigerant in the pipe provided Rutotomoni,
The high pressure side to the low pressure side between the liquid side branch pipe side from the refrigerant heat exchanger of the refrigerant pipe between the outdoor heat exchanger and the liquid side branch pipe and between the refrigerant pipes between the accumulator and the refrigerant heat exchanger. An air conditioner provided with a bypass circuit with a throttle for returning saturated gas to the interior . The refrigerant heat exchanger is composed of an outdoor heat exchanger, an outer pipe for flowing refrigerant between the liquid side branch pipes, and an inner pipe for flowing refrigerant between the four-way switching valve and the accumulator or between the accumulator and the compressor suction port. The air conditioner according to claim 1, wherein the air conditioner has a double pipe structure . The air conditioner according to claim 2, wherein the flow direction of the refrigerant in the outer pipe and the inner pipe of the refrigerant heat exchanger is reversed .

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