JP2009236461A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner can improve COP in cooling and heating simultaneous operation. <P>SOLUTION: In an air conditioning system connecting an outdoor unit 100 to a plurality of indoor units 301-303 by a flow dividing controller 200 and constituting one refrigerating cycle using supercritical fluid, the outdoor unit 100 and the flow dividing controller 200 are connected by three pipes of a high pressure pipe, a low pressure pipe, and a high temperature gas pipe. The flow dividing controller 200 and the plurality of indoor units 301-303 are connected by two pipes of a high pressure pipe 700 and a low pressure pipe 800. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an air conditioner in which an outdoor unit and a plurality of indoor units are connected by a shunt controller and a single refrigeration cycle is configured using a supercritical fluid.

Conventionally, in a heat recovery type air conditioner that uses a supercritical fluid such as CO ₂ to cool and heat at the same time, the outdoor unit and the branch kit are mainly connected by three pipes: a high pressure pipe, a low pressure pipe, and a high temperature gas pipe. Met. In addition, from the branch kit to the indoor unit is a two-pipe type.

  However, the pressure in the critical region of the supercritical fluid is very high, and the wall thickness of the connecting pipe between each unit is significantly higher than in the case of refrigerants typified by conventional chlorofluorocarbons. Or it is easily predicted that the local processing costs such as bending will increase enormously.

  Therefore, it is conceivable to reduce the number of connection pipes by incorporating a branch kit for each indoor unit in one shunt controller in order to reduce connection pipes.

  On the other hand, as a feature of the air conditioner using a supercritical fluid, it is most effective to lower the temperature of the fluid sent to the cooling operation indoor unit and raise the temperature of the fluid sent to the heating operation indoor unit. Realized with low fluid flow rate. For this reason, efficiency (here, COP: Coefficient of Performance) in which the numerator is the capacity of the air conditioner (unit: kW) and the denominator is power consumption (unit: kW) is improved. Therefore, the inlet temperature of the indoor unit, that is, the outlet temperature of the heat source side heat exchanger is basically low during cooling and high during heating.

  However, in the air conditioner that enables simultaneous cooling and heating by the two-pipe type, the following trade-off occurs when the cooling operation indoor unit and the heating operation indoor unit exist (mixed) at the same time.

-It is necessary to supply a low temperature fluid to the cooling operation indoor unit and lower the outlet temperature of the heat source side heat exchanger.
-It is necessary to supply a high-temperature fluid to the heating operation indoor unit and raise the outlet temperature of the heat source side heat exchanger.

  For example, in the conventional cooling main operation (refrigeration cycle is simultaneous cooling and heating operation in the cooling cycle), the heat source side heat exchanger has a certain degree of cooling and heating (for example, pressure of 10 MPa in the supercritical region, around 40 to 50 ° C. in the Mollier diagram). In order to exert its ability as a result, it must be controlled by the outlet temperature, and the difference in enthalpy is insufficient, which is compensated by increasing the fluid flow rate (increasing the power consumption of the compressor), resulting in a decrease in COP. .

  Furthermore, the efficiency of the air conditioner has been evaluated only by the efficiency with respect to 100% load, using the coefficient called COP described above. However, in recent years, for example, loads in general offices have been accompanied by the development of OA equipment and the improvement of the insulation performance of buildings, and cooling loads have also occurred in the heating season, and the frequency of simultaneous cooling and heating increases throughout the year. It is coming. Therefore, the trend of improving the efficiency including the COP in the simultaneous cooling and heating operation is increasing rather than evaluating only with the COP of 100% load.

  As described above, the conventional air-conditioning apparatus has a problem that COP is lowered when it is operated so as to satisfy both the cooling and heating.

  The present invention has been made in view of the above-described points, and an object thereof is to obtain an air conditioner that can improve COP in simultaneous cooling and heating operations.

  An air conditioner according to the present invention is an air conditioner in which an outdoor unit and a plurality of indoor units are connected by a shunt controller and a single refrigeration cycle is configured using a supercritical fluid. It is characterized in that the space is connected by three pipes of a high pressure pipe, a low pressure pipe and a high temperature gas pipe, and the branch flow controller and the plurality of indoor units are connected by two pipes of a high pressure pipe and a low pressure pipe.

  According to the present invention, the outdoor unit and the branch flow controller are connected by three pipes, a high pressure pipe, a low pressure pipe and a high temperature gas pipe, and the high pressure pipe and the low pressure pipe are connected between the branch flow controller and the plurality of indoor units. By connecting with two pipes, the number of pipes connected from the flow dividing controller to each indoor unit can be reduced, and COP in simultaneous cooling and heating operations can be improved. In addition, an energy saving operation can be realized in a cooling main operation in which the cooling main operation is partly heating operation.

Embodiment 1 FIG.
FIG. 1 is a refrigerant circuit diagram at the time of cooling main operation of the air-conditioning apparatus according to Embodiment 1 of the present invention. In the air conditioner shown in FIG. 1, an outdoor unit 100 and a plurality of indoor units 301 to 303 are connected by a shunt controller 200 to form one refrigeration cycle using a supercritical fluid. Mainly includes a compressor 110 and a heat source side heat exchanger 130, and the indoor units 301 to 303 include load side heat exchangers 311 to 313 and expansion valves 321 to 323 as expansion devices, and a shunt controller. 200 mainly includes flow path switching valves 221 to 223, a first expansion valve 211, and a second expansion valve 212.

  Here, the outdoor unit 100 and the shunt controller 200 are connected by three pipes of a high pressure pipe 400, a low pressure pipe 500, and a high temperature gas pipe 600, and the shunt controller 200 and each of the indoor units 301 to 303 are connected with high pressure. Two pipes of a pipe 700 and a low-pressure pipe 800 are connected to each other. Here, it mainly describes cooling operation, and describes the cooling-main operation (hereinafter abbreviated as cooling main operation) of partial heating operation, but about heating-main operation (hereinafter abbreviated as warm main operation) The outdoor unit 100 further includes a four-way valve 120 and check valves 141 to 147 for switching the flow path.

First, the flow in the refrigerant circuit during the cold main operation will be described with reference to FIG. Here, a case where CO ₂ is used as a supercritical fluid will be described. The high-pressure and high-temperature fluid compressed by the compressor 110 is heat-exchanged with the ambient air in the heat source side heat exchanger 130 via the four-way valve 120, cooled to the ambient air temperature, and the heat source side heat exchanger 130 outlet. Becomes a state of high pressure and intermediate temperature.

  The fluid exiting the heat source side heat exchanger 130 flows into the first expansion valve 211 in the shunt controller 200 via the high-pressure pipe 400 and is reduced to an intermediate pressure in the supercritical region slightly lower than the high pressure. It flows into the expansion valves 322 and 323 of the indoor units 302 and 303 that are in the cooling operation through the check valves 232 and 233 and the high-pressure pipe 700 in the middle temperature state, and is further reduced to a low-pressure region and becomes low-pressure and low-temperature. Then, by flowing into the heat exchangers 312 and 313 on the load side, heat is exchanged with room temperature, and the dryness at low pressure and intermediate temperature is high, and the outdoor unit is connected via the low pressure pipe 800, the shunt controller 200 and the low pressure pipe 500. Return to the 100 side. At this time, the second expansion valve 212 is in a closed state.

  On the other hand, the high-pressure and high-temperature gas refrigerant branched from between the compressor 110 and the heat source side heat exchanger 130 enters the shunt controller 200 through the on-off valve 150 and the high-temperature gas pipe 600 to the indoor unit 301 side that performs the heating operation. And flows into the load side heat exchanger 311 of the indoor unit 301 that performs the heating operation via the flow path switching valve 223. The high-pressure and high-temperature gas refrigerant that has flowed into the load-side heat exchanger 311 exchanges heat with room temperature, reaches a high-pressure intermediate temperature that is substantially equal to room temperature, and is decompressed by the expansion valve 321. The medium pressure / medium temperature fluid reduced in pressure joins to the low pressure side of the first expansion valve 211 in the flow dividing controller 200 via the check valve 231.

  Thereby, the number of connecting pipes from the diversion controller 200 to each of the indoor units 301-303 can be reduced, and the COP in the simultaneous cooling and heating operation can be improved.

  Next, FIG. 2 is a refrigerant circuit diagram at the time of heating main operation of the air-conditioning apparatus according to Embodiment 1 of the present invention. The air conditioning apparatus shown in FIG. 2 has a configuration similar to that shown in FIG.

  The flow in the refrigerant circuit during the warm main operation will be described with reference to FIG. The high-pressure and high-temperature fluid compressed by the compressor 110 passes through the four-way valve 120, the heat source side heat exchanger 130, and the high-pressure pipe 400 as in the description of the flow in the refrigerant circuit during the cold main operation. And flows into the load-side heat exchangers 311 and 312 of the indoor units 301 and 302 that perform heating operation via the flow path switching valves 222 and 223. The high-pressure and high-temperature gas refrigerant that has flowed into the load-side heat exchangers 311 and 312 is exchanged with room temperature, becomes a high-pressure medium temperature substantially equal to room temperature, and is decompressed by the expansion valves 321 and 322. The medium pressure / medium temperature fluid reduced in pressure joins to the low pressure side of the first expansion valve 211 in the flow dividing controller 200 via the check valves 231 and 232.

  On the other hand, the medium-pressure medium-temperature fluid supplied from the indoor units 301 and 302 that perform the heating operation branches to the indoor unit 303 that performs the cooling operation and branches in front of the second expansion valve 212. Only the necessary flow rate is supplied via the check valve 233 to the indoor unit 303 that performs the cooling operation, and the remaining partial flow rate is reduced by the second expansion valve 212 and flows into the low-pressure pipe 500. The refrigerant that has flowed into the indoor unit 303 that is performing the cooling operation is further reduced in pressure to a low pressure region by the expansion valve 323, becomes low pressure and low temperature, and flows into the heat exchanger 313 on the load side, thereby exchanging heat with room temperature. The dryness becomes large, and the low pressure pipe 800 returns to the outdoor unit 100 side through the branch controller 200 and the low pressure pipe 500. The refrigerant that has flowed into the low-pressure pipe 500 via the second expansion valve 212 flows into the outdoor unit 100, is heat-exchanged with the surrounding air in the heat source side heat exchanger 130, and is heated to the surrounding air temperature. Then, the low-pressure medium-temperature dryness state becomes large, and the flow returns to the indoor unit 303 via the shunt controller 200.

  Therefore, according to the first embodiment, one outdoor unit 100 and one shunt controller 200 are connected by three pipes of the high-pressure pipe 400, the low-pressure pipe 500, and the high-temperature gas pipe 600. By connecting the indoor units 301 to 303 with the two pipes of the high pressure pipe 700 and the low pressure pipe 800, the number of connection pipes from the shunt controller 200 to each of the indoor units 301 to 303 can be reduced, and the COP can be operated simultaneously with cooling and heating. Can also be improved. Furthermore, energy-saving operation can also be realized in the cooling-main operation in which the cooling operation is a part of the heating operation.

It is a refrigerant circuit figure at the time of the cooling main operation | movement of the air conditioning apparatus which concerns on Embodiment 1 of this invention. It is a refrigerant circuit figure at the time of heating main operation | movement of the air conditioning apparatus which concerns on Embodiment 1 of this invention.

Explanation of symbols

  100 outdoor unit, 110 compressor, 120 four-way valve, 130 heat source side heat exchanger, 141-147 check valve, 150 on-off valve, 200 shunt controller, 211 first expansion valve, 212 second expansion valve, 221-223 flow Road switching valve, 231 to 233 check valve, 301 to 303 indoor unit, 311 to 313 load side heat exchanger, 321 to 323 expansion valve, 400 high pressure piping, 500 low pressure piping, 600 high temperature gas piping, 700 high pressure piping, 800 Low pressure piping.

Claims (2)

In an air conditioner in which an outdoor unit and a plurality of indoor units are connected by a shunt controller and one refrigeration cycle is configured using a supercritical fluid,
Between the outdoor unit and the shunt controller, three pipes, a high pressure pipe, a low pressure pipe and a high temperature gas pipe,
The air conditioner characterized in that the branch controller and the plurality of indoor units are connected by two pipes, a high pressure pipe and a low pressure pipe. In the air conditioning apparatus according to claim 1,
The outdoor unit includes a compressor and a heat source side heat exchanger that exchanges heat between the refrigerant compressed by the compressor and the surrounding air.
The branch flow controller includes a first expansion valve that depressurizes refrigerant flowing from the heat source side heat exchanger of the outdoor unit via the high-pressure pipe between the outdoor unit and the branch flow controller, and the first expansion valve The refrigerant decompressed by the valve and the refrigerant flowing from the indoor unit through the low pressure pipe between the diversion controller and the plurality of indoor units are merged to be between the diversion controller and the plurality of indoor units. The refrigerant flowing into the indoor unit via the high-pressure pipe is branched and decompressed, and together with the refrigerant flowing through the low-pressure pipe between the branch controller and the plurality of indoor units, the outdoor unit And a second expansion valve for flowing out to the outdoor unit via the low-pressure pipe between the flow controller and the branch flow controller,
The refrigerant branched from the compressor flows out into the branch controller through the high-temperature gas pipe, and flows into the indoor unit through the high-pressure pipe between the branch controller and the plurality of indoor units. An air conditioner characterized by.

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