JP2008138923A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioner capable of properly correcting biased flow of a refrigerant flowing in each of heat source-side units, equalizing the refrigerant flow in each of heat source-side units, and sufficiently exerting the assumed horsepower by combining the heat source-side units. <P>SOLUTION: In a heating operation under a low outside air temperature, a control means 40 of the air conditioner 100 controls opening states of an opening and closing valve 23a, an opening and closing valve 23b, a throttle device 21a for bypass and a throttle device 21b for bypass according to the flow of a refrigerant, the refrigerant is guided to an injection circuit, and the openings of the throttle device 21a for bypass of the heat source-side unit 10a and the throttle device 21b for bypass of the heat source-side unit 10b are compared to decide the biased flow of the refrigerant flowing to a main circuit A and a main circuit B, and the liquid back amount of the refrigerant to each compressor or each accumulator to equalize the liquid refrigerant. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air conditioner equipped with a plurality of heat source side units, and in particular, an air conditioner that can appropriately equalize the refrigerant flow rate in each heat source side unit by appropriately correcting the deviation of the refrigerant flow rate in each heat source side unit. It is about.

  2. Description of the Related Art Conventionally, there is an air conditioner that can exhibit a sufficient heating capacity by injecting refrigerant into a compressor even in a cold district where the outside air temperature is minus 10 ° C. (hereinafter referred to as low outside air). . In such a cold district, the flow rate of the refrigerant sucked into the compressor decreases as the outside air decreases, so that the heating capacity decreases. Therefore, by supplying the refrigerant from the injection port of the compressor, the amount of refrigerant in the compressor is increased, the refrigerant density is increased, and the heating capacity is prevented from being lowered.

  As such, “in the refrigerating and air-conditioning apparatus in which the compressor, the indoor heat exchanger, the first pressure reducing device, and the outdoor heat exchanger are connected in an annular shape and supplied with heat from the indoor heat exchanger, the indoor heat exchange is performed. A first internal heat exchanger for exchanging heat between the refrigerant between the storage unit and the first decompressor, the refrigerant between the outdoor heat exchanger and the compressor, the indoor heat exchanger, and the An injection circuit that partially bypasses the refrigerant between the first decompression device and injects the refrigerant into the compression chamber in the compressor, an decompression device for injection provided in the injection circuit, and decompression by the decompression device for injection A refrigerating and air-conditioning apparatus including a second internal heat exchanger that exchanges heat between the generated refrigerant and the refrigerant between the indoor heat exchanger and the first pressure reducing device has been proposed (for example, a patent). Reference 1)

JP 2006-112708 A (page 7, FIG. 1)

  When a plurality of heat source side units of the refrigeration air conditioner having such characteristics are combined, the horsepower can be further increased. However, if a deviation occurs in the flow rate of the refrigerant flowing in each heat source side unit, the horsepower assumed in each heat source side unit cannot be realized. That is, the subject that the horsepower which can be implement | achieved by combining several heat-source side units cannot fully be produced arises. Further, if the refrigerant sucked into a certain compressor is biased, an excessive burden is placed on the compressor, and the possibility of damaging the compressor increases.

  The present invention was made in order to solve the above-described problems, and appropriately corrects the deviation of the flow rate of the refrigerant flowing through each heat source side unit so as to equalize the refrigerant flow rate of each heat source side unit. It aims at providing the air conditioning apparatus which can fully exhibit the horsepower assumed by combining the heat-source side unit.

  An air conditioner according to the present invention includes one or more load-side units including a load-side heat exchanger and a load-side throttle device, a compressor, a flow path switching valve, a refrigerant heat exchanger, and a heat source-side throttle device. And a heat source side exchanger, and a bypass throttling device, a refrigerant heat exchanger, a first on-off valve, and an injection pipe formed by branching a refrigerant pipe between the refrigerant heat exchanger and the load side throttling device, An air conditioner in which two or more heat source side units forming an injection circuit in which injection ports of a compressor are sequentially connected are connected, and the first opening / closing is performed when the outside air temperature is lower than a predetermined reference temperature value A control means for controlling the valve and the bypass throttling device in an open state in accordance with a flow rate of the refrigerant, and for causing the refrigerant to flow through the injection pipe, wherein the control means includes the two or more heat sources; By comparing the degree of opening of the bypass throttle device of the unit, to determine the liquid back amount of the refrigerant to each compressor, characterized in that to correct the deviation of the liquid refrigerant flow to the compression chambers.

  In addition, the air conditioner according to the present invention includes one or more load-side units including a load-side heat exchanger and a load-side throttle device, a compressor, a flow path switching valve, a refrigerant heat exchanger, and a heat source side. A throttle device, a heat source side exchanger, and an accumulator, and a bypass throttle device, a refrigerant heat exchanger, a first injection pipe formed by branching a refrigerant pipe between the refrigerant heat exchanger and the load side throttle device An air conditioner that connects two or more heat source units that form an injection circuit in which an on-off valve and an injection port of the compressor are sequentially connected, and the outside air temperature is lower than a predetermined reference temperature value, Control means for controlling the first on-off valve and the bypass throttling device to an open state in accordance with the flow rate of the refrigerant, and causing the refrigerant to flow through the injection pipe, the control means The amount of refrigerant liquid back to each accumulator is judged by comparing the opening degree of each bypass expansion device of the two or more heat source side units, and the deviation of the liquid refrigerant flow rate to each accumulator is corrected. It is characterized by.

  In the air conditioner according to the present invention, after the control means makes the refrigerant flow to the injection circuit, the opening degree of each of the bypass throttling devices is compared, and the liquid refrigerant flow rate is biased by the amount of liquid back to each compressor. Since the judgment can be made to equalize the flow rate of the liquid refrigerant to each compressor, it is possible to prevent the heating capacity from being lowered even in low outside air. Further, since the liquid refrigerant flowing into any of the compressors is not biased, damage to the compressor can be reduced without placing an excessive burden on the compressor.

  In the air conditioner according to the present invention, the control means makes the refrigerant flow to the injection circuit, compares the opening degree of each bypass throttling device, and the liquid refrigerant flow rate is biased by the liquid back amount to each accumulator. Therefore, it is possible to equalize the liquid refrigerant flow rate of each accumulator, so that it is possible to prevent the heating capacity from being lowered even in low outside air. Further, since the liquid refrigerant flowing into any of the accumulators is not biased, damage to the compressor can be reduced without imposing an excessive burden on the compressor.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of an air-conditioning apparatus 100 according to an embodiment of the present invention. Based on FIG. 1, the circuit configuration of the air conditioning apparatus 100 will be described. The air conditioner 100 performs a cooling operation and a heating operation using a refrigeration cycle (heat pump cycle) for circulating a refrigerant. In addition, in the following drawings including FIG. 1, the relationship of the size of each component may be different from the actual one.

  The air conditioner 100 includes two heat source side units (a heat source side unit 10a and a heat source side unit 10b) and a load side unit 50. That is, the air conditioning apparatus 100 is equipped with a plurality of heat source side units. These units are connected to each other by a liquid pipe 1 that is a refrigerant pipe and a gas pipe 2 that is a refrigerant pipe. Specifically, the heat source side unit 10a and the load side unit 50 include a compressor 11a, a four-way valve 13a as a flow path switching valve, a load side heat exchanger 52, a load side expansion device 51, a refrigerant heat exchanger 16a, a heat source. The side expansion device 15a and the heat source side exchanger 14a are connected by a main circuit A which is a refrigerant circuit in which the liquid pipe 1 and the gas pipe 2 are sequentially connected.

  Similarly, the heat source side unit 10b and the load side unit 50 also have a compressor 11b, a four-way valve 13b as a flow path switching valve, a load side heat exchanger 52, a load side expansion device 51, a refrigerant heat exchanger 16b, and a heat source side. The expansion device 15b and the heat source side exchanger 14b are connected by a main circuit B which is a refrigerant circuit in which the liquid pipe 1 and the gas pipe 2 are sequentially connected. That is, when the refrigerant circulates through the main circuit A and the main circuit B, the air conditioner 100 can perform the cooling operation and the heating operation. In this embodiment, the case where two units of the heat source side unit 10a and the heat source side unit 10b are mounted on the air conditioner 100 is shown as an example. May be mounted.

  A main refrigerant circuit and an injection circuit are formed in the heat source side unit 10a and the heat source side unit 10b. The main refrigerant circuit of the heat source side unit 10a includes a compressor 11a, an oil separation device 12a, a four-way valve 13a, a heat source side heat exchanger 14a, a heat source side expansion device 15a, a refrigerant heat exchanger 16a, and an accumulator 18a. Are sequentially connected. Similarly, the main refrigerant circuit of the heat source side unit 10b includes the compressor 11b, the oil separation device 12b, the four-way valve 13b, the heat source side heat exchanger 14b, the heat source side expansion device 15b, and the refrigerant heat exchanger 16b. And the accumulator 18b are sequentially connected.

  The compressor 11a and the compressor 11b suck the refrigerant flowing through the liquid pipe 1 and compress the refrigerant into a high temperature / high pressure state. For example, the number of revolutions is controlled by an inverter and the capacity is controlled. It should be composed of things. The compressor 11a and the compressor 11b have a structure capable of injecting (injecting) refrigerant supplied from an injection circuit into a compression chamber inside. The oil separator 12a and the oil separator 12b have a function of separating the refrigerator oil component from the refrigerant gas in which the refrigerator oil is mixed.

  The separated refrigerating machine oil is a capillary pipe 17a provided in a refrigerant pipe connecting the suction side pipe connected to the compressor 11a and the oil separator 12a, and a suction side pipe connected to the compressor 11b. The flow rate is controlled by a capillary tube 17b provided in a refrigerant pipe that communicates with the oil separator 12b so as to be returned to the compressor 11a and the compressor 11b. The four-way valve 13a and the four-way valve 13b switch the refrigerant flow between the cooling operation and the heating operation.

  The heat source side heat exchanger 14a and the heat source side heat exchanger 14b function as a condenser during cooling operation and as an evaporator during heating operation, and exchange heat between air supplied from a fan (not shown) and the refrigerant. The refrigerant is vaporized or condensed and liquefied. The heat source side expansion device 15a and the heat source side expansion device 15b function as a pressure reducing valve or an expansion valve, and decompress the refrigerant to expand it. It is assumed that the heat source side expansion device 15a and the heat source side expansion device 15b are configured by a device whose opening degree can be variably controlled, for example, an electronic expansion valve. The refrigerant heat exchanger 16a and the refrigerant heat exchanger 16b exchange heat between the refrigerant flowing through the main refrigerant circuit and the refrigerant flowing through the injection circuit. The accumulator 18a and the accumulator 18b store excess refrigerant.

  In the injection circuit of the heat source side unit 10a, the injection pipe 20a obtained by branching the liquid pipe 1 between the refrigerant heat exchanger 16a and the load side expansion device 51 of the load side unit 50 is connected to the injection port of the compressor 11a. It consists of Further, the injection pipe 20a between the branched portion of the liquid pipe 1 and the refrigerant heat exchanger 16a is provided with a bypass expansion device 21a. This injection pipe 20a is further branched between the refrigerant heat exchanger 16a and the compressor 11a, one is connected to the accumulator 18a via the on-off valve 22a, and the other is connected via the on-off valve 23a, which is the first on-off valve. To the injection port of the compressor 11a.

  Similarly, in the injection circuit of the heat source side unit 10b, the injection pipe 20b obtained by branching the liquid pipe 1 between the refrigerant heat exchanger 16b and the load side expansion device 51 of the load side unit 50 is connected to the injection port of the compressor 11b. Is made up of. Further, the injection pipe 20b between the portion branched from the liquid pipe 1 and the refrigerant heat exchanger 16b is provided with a bypass expansion device 21b. The injection pipe 20b is further branched between the refrigerant heat exchanger 16b and the compressor 11b, one of which is connected to the accumulator 18b via the on-off valve 22b, and the other is connected to the on-off valve 23b which is the first on-off valve. And connected to the injection port of the compressor 11b.

  The bypass throttling device 21a and the bypass throttling device 21b function as a pressure reducing valve and an expansion valve, and decompress the refrigerant to expand it. The bypass throttling device 21a and the bypass throttling device 21b are assumed to be configured by an opening that can be variably controlled, for example, an electronic expansion valve. That is, by flowing a part of the refrigerant flowing through the main refrigerant circuit into the injection circuit, in the refrigerant heat exchanger 16a and the refrigerant heat exchanger 16b, the refrigerant flowing through the main refrigerant circuit (liquid pipe 1), the injection pipe 20a, Heat is exchanged with the refrigerant that has flowed through the injection circuit 20b and has been depressurized by the bypass throttling device 21a and the bypass throttling device 21b and has become low temperature.

  The on-off valve 22a and the on-off valve 22b are controlled to be opened / closed by the control means 40 and may or may not conduct the refrigerant. The opening / closing valve 23a and the opening / closing valve 23b are also controlled to be opened / closed by the control means 40 and may or may not conduct the refrigerant. That is, by opening the on-off valve 23a and the on-off valve 23b, the refrigerant is conducted to the injection pipe 20a and the injection pipe 20b to form an injection circuit.

  Note that the pressure between the on-off valve 23a and the compressor 11a (between the on-off valve 23b and the compressor 11b) when the refrigerant is not conducted to the injection circuit is driven by the compressor 11a (compressor 11b). It may fluctuate greatly and may become larger or smaller than the pressure between the bypass throttling device 21a and the on-off valve 23a (between the bypass throttling device 21b and the on-off valve 23b). This may cause the on-off valve 23a (the on-off valve 23b) to vibrate and break. In order to avoid this, the on-off valve 22a (on-off valve 22b) is opened, and the pressure between the bypass throttling device 21a and the on-off valve 23a (between the bypass throttling device 21b and the on-off valve 23b) is always opened and closed. The pressure is smaller than the pressure between the valve 23a and the compressor 11a (between the on-off valve 23b and the compressor 11b).

  In the heat source side unit 10a and the heat source side unit 10b, the discharge temperature sensor 3a and the discharge temperature sensor 3b for detecting the temperature of the refrigerant discharged from the compressor 11a and the compressor 11b, and the injection pipe 20a and the injection pipe 20b are electrically connected. There are provided an injection temperature sensor 4a and an injection temperature sensor 4b for detecting the temperature of the refrigerant. The discharge temperature sensor 3a and the discharge temperature sensor 3b are installed in the discharge side piping connected to the compressor 11a and the compressor 11b. The injection temperature sensor 4a is installed in the injection pipe 20a between the refrigerant heat exchanger 16a and the on-off valve 22a and on-off valve 23a. Similarly, the injection temperature sensor 4b is installed in the injection pipe 20b between the refrigerant heat exchanger 16b and the on-off valve 22b and on-off valve 23b.

  Further, in the heat source side unit 10a and the heat source side unit 10b, a high pressure side pressure sensor 5a and a high pressure side pressure sensor 5b for detecting the high pressure of the refrigerant discharged from the compressor 11a and the compressor 11b, and the heat source side unit 10a and The refrigerant pressure sensor 6a and the refrigerant pressure sensor 6b for detecting the pressure of the refrigerant passing through the liquid pipe 1 connecting the heat source side unit 10b and the load side unit 50, and the low pressure of the refrigerant sucked into the compressor 11a and the compressor 11b A low-pressure side pressure sensor 7a and a low-pressure side pressure sensor 7b are provided.

  The high pressure side pressure sensor 5a and the high pressure side pressure sensor 5b are installed between the oil separator 12a and the oil separator 12b and the four-way valve 13a and the four-way valve 13b. The refrigerant pressure sensor 6 a and the refrigerant pressure sensor 6 b are installed in the liquid pipe 1 that connects the heat source side unit 10 a, the heat source side unit 10 b, and the load side unit 50. The low-pressure side pressure sensor 7a and the low-pressure side pressure sensor 7b are installed between the four-way valve 13a and the four-way valve 13b, and the accumulator 18a and accumulator 18b. The temperature information and pressure information detected by each temperature sensor and each pressure sensor are sent to the control means 40.

  A load side expansion device 51 and a load side heat exchanger 52 are mounted on the load side unit 50. The load side throttle device 51 functions as a pressure reducing valve or an expansion valve, and decompresses the refrigerant to expand it. It is assumed that the load side throttle device 51 is configured by a device whose opening degree can be variably controlled, for example, an electronic expansion valve. The load-side heat exchanger 52 functions as an evaporator during the cooling operation and as a condenser during the heating operation, and performs heat exchange between the refrigerant and the air, and evaporates or condenses the refrigerant. In this embodiment, the case where one load-side unit 50 is mounted on the air-conditioning apparatus 100 is shown as an example, but the present invention is not limited to this, and a plurality of units may be mounted.

  The liquid pipe 1 and the gas pipe 2 are refrigerant pipes that conduct the refrigerant circulating in the refrigeration cycle. The injection pipe 20a and the injection pipe 20b are also refrigerant pipes that conduct the refrigerant. Further, the driving frequency of the compressor 11a and the compressor 11b, the heat source side expansion device 15a and the heat source side expansion device 15b, the bypass expansion device 21a and the bypass expansion device 21b, the load side expansion device 51a and the load side expansion device. The control means 40 controls the opening degree with respect to 51b, the on-off valve 22a and the on-off valve 22b, and the on-off valve 23a and the on-off valve 23b.

  The control means 40 has a function of comprehensively controlling the entire air conditioner 100. That is, the control means 40 controls each device based on information sent from each temperature sensor or each pressure sensor. Here, the case where the control means 40 is provided outside the heat source side unit 10a and the heat source side unit 10b is described as an example, but the present invention is not limited to this. For example, it may be provided in any one of the heat source side units or may be provided in the load side unit 50.

The refrigerant | coolant which can be used for the air conditioning apparatus 100 is demonstrated.
Examples of the refrigerant that can be used in the refrigeration cycle of the air conditioner 100 include a non-azeotropic refrigerant mixture, a pseudo-azeotropic refrigerant mixture, and a single refrigerant. Non-azeotropic refrigerant mixture includes R407C (R32 / R125 / R134a) which is an HFC (hydrofluorocarbon) refrigerant. Since this non-azeotropic refrigerant mixture is a mixture of refrigerants having different boiling points, it has a characteristic that the composition ratio of the liquid-phase refrigerant and the gas-phase refrigerant is different. The pseudo azeotropic refrigerant mixture includes R410A (R32 / R125) and R404A (R125 / R143a / R134a) which are HFC refrigerants. This pseudo azeotrope refrigerant has the same characteristic as that of the non-azeotrope refrigerant and has an operating pressure of about 1.6 times that of R22.

  The single refrigerant includes R22, which is an HCFC (hydrochlorofluorocarbon) refrigerant, R134a, which is an HFC refrigerant, and the like. Since this single refrigerant is not a mixture, it has the property of being easy to handle. In addition, carbon dioxide, propane, isobutane, ammonia, etc., which are natural refrigerants, can also be used. R22 represents chlorodifluoromethane, R32 represents difluoromethane, R125 represents pentafluoroethane, R134a represents 1,1,1,2-tetrafluoroethane, and R143a represents 1,1,1-trifluoroethane. ing. Therefore, it is good to use the refrigerant | coolant according to the use and the objective of the air conditioning apparatus 100. FIG.

Here, operation | movement of the air conditioning apparatus 100 is demonstrated.
First, the heating operation when the outside air temperature is relatively high will be described. Based on FIG. 1, the refrigerant | coolant state at the time of the heating operation of the air conditioning apparatus 100 is demonstrated. When the air conditioning apparatus 100 starts the heating operation, the compressor 11a is first driven. The high-temperature and high-pressure gas refrigerant discharged from the compressor 11a flows out from the heat source side unit 10a via the oil separator 12a and the four-way valve 13a, flows through the gas pipe 2, and is loaded on the load side in the load side unit 50. The heat exchanger 52 is reached. In the load-side heat exchanger 52, the gas refrigerant is condensed and liquefied while dissipating heat to air or water, and becomes a low-temperature / high-pressure liquid refrigerant. In other words, the heating operation is performed by giving the heat stored in the refrigerant to the air or water on the load side.

  The liquid refrigerant condensed and liquefied by the load-side heat exchanger 52 is decompressed to an intermediate pressure by the load-side expansion device 51 to become an intermediate-pressure liquid refrigerant or a gas-liquid two-phase refrigerant. This intermediate-pressure liquid refrigerant or gas-liquid two-phase refrigerant flows out of the load side unit 50, flows through the liquid pipe 1, and reaches the heat source side unit 10a. Here, since the outside air temperature is relatively high, the refrigerant does not flow into the injection circuit. That is, the bypass throttle device 21a and the on-off valve 23a are controlled to be in a closed state.

  In such a state, the refrigerant that has flowed into the heat source side unit 10a passes through the refrigerant heat exchanger 16a and is then depressurized by the heat source side expansion device 15a to become a low-pressure / low-temperature liquid refrigerant or a gas-liquid two-phase refrigerant. This refrigerant evaporates into a gas refrigerant by exchanging heat with air in the heat source side heat exchanger 14a. That is, the state is changed to gas by absorbing heat from the air supplied to the heat source side heat exchanger 14a. The gas refrigerant passes through the four-way valve 13a and the accumulator 18a and is then sucked into the compressor 11a. In addition, since a refrigerant | coolant does not flow into an injection circuit, heat exchange is not performed in the refrigerant | coolant heat exchanger 16a.

  Further, when the air conditioning load is large, the air conditioner 100 can operate the heat source side unit 10a and the heat source side unit 10b at the same time as appropriate. This is because by operating the heat source side unit 10a and the heat source side unit 10b of a plurality of systems at the same time, the flow rate of the refrigerant circulating in the refrigeration cycle can be increased, and accordingly the heating capacity can be improved. That is, by mounting a plurality of heat source side units on the air conditioner 100, the horsepower of the air conditioner 100 can be increased. In addition, you may make it operate the heat source side unit 10a simultaneously in the state which operated the heat source side unit 10b.

  Here, the flow rate adjustment of the refrigerant flowing through the main circuit A and the main circuit B when the outside air temperature is relatively high will be described. The surplus refrigerant in the main circuit A and the main circuit B of the air conditioner 100 is stored as a liquid refrigerant in the accumulator 18a and the accumulator 18b. The amount of liquid refrigerant stored in the accumulator 18a and the accumulator 18b is not necessarily the same depending on the air conditioning load and the operating conditions of the heat source side unit 10a and the heat source side unit 10b. In general, when the amount of liquid refrigerant in the accumulator 18a and the accumulator 18b is biased, the liquid refrigerant flow rate is adjusted by controlling the opening degree of the heat source side expansion device 15a and the heat source side expansion device 15b. (Correct). The liquid refrigerant flow rate deviation correction process will be described in detail with reference to FIGS. 4 and 5.

  A case where the amount of liquid refrigerant in the accumulator 18a is large will be described as an example. When the amount of the liquid refrigerant in the accumulator 18a increases and the liquid refrigerant is likely to overflow, the refrigerant sucked into the compressor 11a of the main circuit A becomes wet, and the temperature of the discharged refrigerant decreases. As a result, the refrigerant is biased toward the main circuit A. The control unit 40 determines whether the temperature of the refrigerant is lowered based on the refrigerant discharge temperature information detected by the discharge temperature sensor 3a and the saturation temperature of the refrigerant discharge pressure detected by the high-pressure sensor 5a. Yes. Therefore, the control means 40 obtains the degree of superheat (hereinafter referred to as “discharge SH”) that is the difference between the refrigerant discharge temperature and the saturation temperature of the refrigerant discharge pressure, and determines whether the value is equal to or less than a predetermined value. This bias is judged.

  When the control unit 40 determines that the refrigerant discharge SH discharged from the compressor 11a is equal to or less than a predetermined value, the control unit 40 performs control so as to reduce the opening degree of the heat source side expansion device 15a. By doing so, the refrigerant flow rate of the main circuit A can be made smaller than the refrigerant flow rate of the main circuit B, and the refrigerant flowing out from the heat source side heat exchanger 14a becomes dry. As a result, the amount of refrigerant liquid stored and held in the accumulator 18a decreases. That is, the refrigerant flow rate biased to the main circuit A is adjusted, and the refrigerant flow rate of the main circuit A and the refrigerant flow rate of the main circuit B can be corrected.

  Next, the heating operation when the outside air temperature is relatively low, that is, when the outside air temperature is −10 ° C. or lower (low outside air) will be described. FIG. 2 is a Mollier diagram (P-H diagram) showing the refrigerant state of the heating operation when the outside air temperature is relatively low. Based on FIG.1 and FIG.2, the refrigerant | coolant state at the time of the heating operation in case the external temperature of the air conditioning apparatus 100 is comparatively low is demonstrated. In FIG. 2, the vertical axis represents the absolute pressure (P) and the horizontal axis represents the specific enthalpy (H). In addition, the refrigerant is in a gas-liquid two-phase state at the portion surrounded by the saturated liquid line and the saturated vapor line, is liquefied on the left side of the saturated liquid line, and is gas on the right side of the saturated vapor line. It represents that it is in a state of becoming. This Mollier diagram shows the state of the R410A refrigerant.

  When the air conditioning apparatus 100 starts the heating operation, the compressor 11a is first driven. The high-temperature and high-pressure gas refrigerant (state (a)) discharged from the compressor 11a flows out of the heat source side unit 10a via the oil separator 12a and the four-way valve 13a, flows through the gas pipe 2, and flows to the load side. The load-side heat exchanger 52 in the unit 50 is reached. In the load-side heat exchanger 52, the gas refrigerant is condensed and liquefied while dissipating heat to air or water, and becomes a low-temperature / high-pressure liquid refrigerant (state (b)). In other words, the heating operation is performed by giving the heat stored in the refrigerant to the air or water on the load side.

  Further, the condensed and liquefied liquid refrigerant is depressurized to an intermediate pressure by the load side expansion device 51, and becomes an intermediate pressure liquid refrigerant or a gas-liquid two-phase refrigerant (state (c)). This intermediate-pressure liquid refrigerant or gas-liquid two-phase refrigerant flows out of the load side unit 50, flows through the liquid pipe 1, and reaches the heat source side unit 10a. Here, since the outside air is low, a part of the refrigerant is allowed to flow into the injection circuit. The control means 40 controls the bypass expansion device 21a and the on-off valve 23a to be in an open state, and diverts the refrigerant that has flowed into the heat source side unit 10a. That is, the refrigerant flowing into the heat source side unit 10a is divided into the main refrigerant circuit and the injection circuit. Note that the on-off valve 22a may be controlled to be in a closed state so that the refrigerant is conducted to the injection circuit.

  The refrigerant divided into the main refrigerant circuit is exchanged in the refrigerant heat exchanger 16a with the low-temperature / low-pressure refrigerant (state (g)) that is diverted into the injection circuit and slightly decompressed by the bypass expansion device 21a. It is cooled and becomes a low-temperature and high-pressure liquid refrigerant (state (d)). This liquid refrigerant passes through the refrigerant heat exchanger 16a and is then depressurized by the heat source side expansion device 15a to become a low-temperature / low-pressure gas-liquid two-phase refrigerant (state (e)). This gas-liquid two-phase refrigerant exchanges heat with air in the heat source side heat exchanger 14a, thereby evaporating gas to become a gas refrigerant (state (f)). That is, the state is changed to gas by absorbing heat from the air supplied to the heat source side heat exchanger 14a. The gas refrigerant passes through the four-way valve 13a and the accumulator 18a and is then sucked into the compressor 11a.

  On the other hand, the refrigerant diverted to the injection circuit is decompressed by the bypass throttling device 21a and becomes a low-temperature / low-pressure gas-liquid two-phase refrigerant (state (g)). The gas-liquid two-phase refrigerant flows into the refrigerant heat exchanger 16a, exchanges heat with an intermediate-pressure liquid refrigerant or gas-liquid two-phase refrigerant (state (c)) flowing through the main refrigerant circuit, and is heated (state ( h)). In other words, the refrigerant flowing through the injection circuit becomes a slightly dry refrigerant by exchanging heat with the refrigerant flowing through the main refrigerant circuit in the refrigerant heat exchanger 16a. And this refrigerant | coolant is injected into the injection port of the compressor 11a through the on-off valve 23a.

  In the compressor 11a, the refrigerant sucked through the main refrigerant circuit (state (f)) is compressed and heated to an intermediate pressure (state (i)) and then injected from the injection circuit (state (h)). ). The merged refrigerant is compressed to a high pressure (state (a)) and discharged again after the temperature is slightly lowered (state (j)). In the heating operation when the outside air temperature is relatively low, heat exchange with the outside air has to be performed, so that the evaporation temperature of the refrigerant decreases, and the evaporation pressure (low pressure) decreases accordingly.

  Therefore, in the refrigeration cycle that does not include the injection circuit, the density of the refrigerant sucked into the compressor is lowered, so that the refrigerant flow rate is reduced and the compression ratio is increased. That is, the capacity of the refrigeration cycle is reduced. In contrast, in the refrigeration cycle including the injection circuit as in the air-conditioning apparatus 100 according to this embodiment, the intermediate pressure refrigerant (state (g)) is injected during the compression process of the compressor 11a to produce the refrigerant. The flow rate can be increased (the refrigerant density can be improved). That is, the heating capacity can be maintained even in low outside air without abnormally increasing the discharge temperature from the compressor 11a.

  Further, when the air conditioning load is large, the air conditioner 100 can operate the heat source side unit 10a and the heat source side unit 10b at the same time as appropriate. This is because by operating the heat source side unit 10a and the heat source side unit 10b of a plurality of systems at the same time, the flow rate of the refrigerant circulating in the refrigeration cycle can be increased, and accordingly the heating capacity can be improved. That is, by mounting a plurality of heat source side units on the air conditioner 100, the horsepower of the air conditioner 100 can be increased.

  Here, the flow rate adjustment of the refrigerant flowing through the main circuit A and the main circuit B in the case of low outside air will be described. Even in the case of low outside air, as in the case where the outside air temperature is relatively high, excess refrigerant in the main circuit A and the main circuit B of the air conditioner 100 is stored as liquid refrigerant in the accumulator 18a and accumulator 18b. . Further, similarly to the case where the outside air temperature is relatively high, the liquid refrigerant liquid amounts stored in the accumulator 18a and the accumulator 18b are not necessarily the same. Therefore, the liquid refrigerant flow rate is adjusted (corrected) by controlling the opening degree of the heat source side expansion device 15a and the heat source side expansion device 15b. The liquid refrigerant flow rate deviation correction process will be described in detail with reference to FIGS. 4 and 5.

  A case where the amount of liquid refrigerant in the accumulator 18a is large will be described as an example. For example, when the refrigerant flow rate of the main circuit A is higher than the refrigerant flow rate of the main circuit B, or when the intake air temperature of the heat source side heat exchanger 14a is lower than the intake air temperature of the heat source side heat exchanger 14b, the heat source side heat When the air volume of the exchanger 14a is smaller than the air volume of the heat source side heat exchanger 14b, etc., the refrigerant cannot completely evaporate in the heat source side heat exchanger 14a of the main circuit A and a liquid back is generated in the accumulator 18a. The amount of refrigerant liquid increases. As described above, when the accumulator 18a is likely to overflow, the refrigerant sucked into the compressor 11a of the main circuit A becomes wet, and the temperature of the discharged refrigerant is lowered without being injected into the compressor 11a. End up.

  Therefore, in such a state, the opening degree of the bypass expansion device 21a is smaller than the opening degree of the bypass expansion device 21b. If it does so, the refrigerant | coolant flow volume which flows through the main circuit A will increase rather than the refrigerant | coolant flow volume which flows through an injection circuit, and it will be in the state where the opening degree of the expansion apparatus for bypasses is small, ie, the refrigerant | coolant is biased to the main circuit A. Therefore, the control means 40 compares the opening of the bypass expansion device 21a and the opening of the bypass expansion device 21b to determine the deviation of the refrigerant flow rate. When the accumulator is not mounted, it is preferable to determine the deviation of the refrigerant flow rate of each main circuit based on the amount of liquid back generated in the compressor.

  When the control means 40 compares the opening of the bypass expansion device 21a with the opening of the bypass expansion device 21b and determines that the opening of the bypass expansion device 21a is smaller, the control circuit 40 Since the refrigerant is in a biased state, the opening degree of the heat source side expansion device 15a is controlled to be small. By doing so, the refrigerant flow rate of the main circuit A can be made smaller than the refrigerant flow rate of the main circuit B, and the refrigerant flowing out from the heat source side heat exchanger 14a becomes dry. As a result, the amount of refrigerant liquid stored and held in the accumulator 18a decreases.

  That is, the refrigerant flow rate biased to the main circuit A is adjusted, and the refrigerant flow rate of the main circuit A and the refrigerant flow rate of the main circuit B can be corrected. Note that here, adjustment of the accumulator liquid back amount that occurs due to variations in the refrigerant flow rate has been described, but due to differences in the intake air temperature of the heat source side heat exchanger and installation conditions, only on the heat source side unit on one side. Adjustment (correction) is possible in the same way even when the accumulator is likely to overflow due to liquid back due to the application of static pressure and variations in the air volume.

  Here, the flow rate of the refrigerant to be injected into the injection port of the compressor will be described. FIG. 3 is an explanatory diagram for explaining the flow rate of refrigerant to be injected (hereinafter referred to as injection flow rate). FIG. 3A shows the relationship between the discharge SH and the injection flow rate with the discharge SH on the vertical axis and the injection flow rate on the horizontal axis. FIG. 3B shows the injection flow rate on the vertical axis and the opening degree of the bypass throttle device on the horizontal axis, and shows the relationship between the injection flow rate and the opening degree of the bypass throttle device.

  The injection flow rates of the heat source side unit 10a and the heat source side unit 10b are adjusted by controlling the opening degree of the bypass expansion device 21a and the bypass expansion device 21b. When the injection flow rate increases, the discharge temperature of the refrigerant discharged from the compressor 11a and the compressor 11b decreases. Therefore, as shown in FIG. 3A, the discharge SH tends to decrease. When the injection flow rate is excessive, a large amount of liquid refrigerant flows into the compressor 11a and the compressor 11b, and an excessive load is applied to the compressor 11a and the compressor 11b. If it does so, possibility that the compressor 11a and the compressor 11b will be damaged will become high.

  On the other hand, when the opening degree of the bypass expansion device 21a and the bypass expansion device 21b is increased, the injection flow rate tends to increase as shown in FIG. Based on the above, the air conditioner 100 adjusts the opening degree of the bypass expansion device 21a and the bypass expansion device 21b so that the discharge SH of the compressor 11a and the compressor 11b is constant, and the compressor 11a And the flow volume of the excessive refrigerant | coolant which injects into the injection port of the compressor 11b is prevented. Further, the refrigerant flow rate of the main circuit A and the refrigerant flow rate of the main circuit B are adjusted by comparing the degree of opening of the bypass expansion device 21a and the bypass expansion device 21b.

  Hereinafter, the flow of processing for correcting the deviation between the refrigerant flow rate of the main circuit A and the refrigerant flow rate of the main circuit B (reflective flow rate deviation correction processing) will be described. FIG. 4 is a flowchart showing the flow of a refrigerant flow rate deviation correction process. Based on FIG. 4, the flow of the refrigerant flow rate deviation correction process when two heat source side units (the heat source side unit 10a and the heat source side unit 10b) are operating will be described. It is to be noted that the correction of the unevenness of the liquid back amount generated according to the installation environment of each heat source side unit and the variation among the respective heat source side units is performed by the refrigerant flow rate.

  In order to exhibit the performance of the air conditioner 100 efficiently, it is desirable that the refrigerant flow rate of the main circuit A and the refrigerant flow rate of the main circuit B be uniform to some extent. However, the refrigerant flow rate in the main circuit A and the refrigerant flow rate in the main circuit B are biased depending on the air conditioning load and the operating conditions of the heat source side unit 10a and the heat source side unit 10b. Therefore, the air conditioner 100 periodically performs a correction process of the refrigerant flow rate deviation so that the refrigerant flow rate of the main circuit A and the refrigerant flow rate of the main circuit B are equalized.

  First, when the air conditioning apparatus 100 starts a heating operation, the control means 40 determines whether or not a predetermined time set in advance has elapsed (step S101). Note that the predetermined time is not particularly limited as long as it is determined based on various conditions such as horsepower, usage, and installation location of the air conditioner 100. Further, it is preferable that the predetermined time can be changed. Further, the user may arbitrarily set a predetermined time. When it is determined that the predetermined time has elapsed (step S101; Yes), the control unit 40 calculates the opening degree (LEV2) of the heat source side expansion device 15a and the heat source side expansion device 15b (step S102).

  That is, the control means 40 calculates LEV2 based on LEV2 = LEV2 * × k (Pm−Pmm). Here, LEV2 * is the opening degree of the current heat source side expansion device 15a and the heat source side expansion device 15b, Pm is the refrigerant pressure value detected by the low pressure side pressure sensor 7a and the low pressure side pressure sensor 7b, and Pmm is the low pressure side. The target pressure value of the refrigerant detected by the pressure sensor 7a and the low pressure side pressure sensor 7b, k is a coefficient for determining the opening degree of the heat source side expansion device 15a and the heat source side expansion device 15b according to the difference between Pm and Pmm. Respectively. In addition, since the opening degree of the heat source side expansion device 15a and the heat source side expansion device 15b is the same until a predetermined time elapses, only one of the opening amounts may be calculated.

  Next, the control means 40 determines whether or not the outside air temperature is higher than a preset reference temperature value (step S103). Here, the control means 40 determines whether the operation is in the case of low outside air or the operation in the case where the outside air temperature is relatively high (including cooling operation). When the control means 40 determines that the outside air temperature is lower than the reference temperature value, that is, low outside air (step S103; Yes), the opening degree of the bypass throttling device 21a (LEV1a) and the opening degree of the bypass throttling device 21b. (LEV1b) is compared (step S104).

  In the case of low outside air, since the refrigerant is circulated through the injection circuit in order to maintain the heating capacity, the bypass expansion device 21a and the bypass expansion device 21b are open. Therefore, the control means 40 compares the LEV 1a with the LEV 1b to determine the deviation of the refrigerant flow rate. When the control means 40 determines that LEV1a is larger (step S104; No), the opening degree (LEV2a) of the heat source side expansion device 15a is set to a value obtained by adding the correction value α to LEV2 (LEV2a = LEV2 + α) ( Step S106). That is, when the LEV 1a is larger, the refrigerant flow rate is biased toward the main circuit B, so the opening degree of the heat source side expansion device 15a of the main circuit A is set to be larger.

  When the control means 40 determines that LEV1a is smaller (step S104; Yes), the opening degree (LEV2b) of the heat source side expansion device 15b is set to a value obtained by adding the correction value α to LEV2 (LEV2b = LEV2 + α). (Step S106). That is, when the LEV 1b is larger, the refrigerant flow rate is biased toward the main circuit A, so the opening degree of the heat source side expansion device 15b of the main circuit B is set to be larger. Thereafter, the newly set LEV 2a and LEV 2b are maintained until a predetermined time elapses. That is, in the case of the low outside air, the air conditioner 100 compares the LEV 1a and the LEV 1b to determine the deviation of the refrigerant flow rate, corrects the LEV 2a and the LEV 2b as appropriate, and equalizes the refrigerant flow rate. It is.

  On the other hand, when the control means 40 determines that the outside air temperature is higher than the reference temperature value (step S103; No), the refrigerant discharge SH (TdSHa) discharged from the compressor 11a and the refrigerant discharged from the compressor 11b. The discharge SH (TdSHb) is compared with a predetermined value set in advance (step S107). When the outside air temperature is relatively high, the refrigerant is not passed through the injection circuit, so that the bypass expansion device 21a and the bypass expansion device 21b are closed. That is, the opening degree of the bypass expansion device 21a cannot be compared with the opening amount of the bypass expansion device 21b.

  Therefore, the control means 40 compares TdSHa and TdSHb with a predetermined value to determine the deviation of the refrigerant flow rate. When it is determined that both TdSHa and TdSHb are larger than the predetermined values (step S107; Yes), the control unit 40 sets LEV2a and LEV2b to the value of LEV2 calculated in step S102 (step S110). That is, in this case, since the refrigerant flow rate is not biased, both the LEV 2a and LEV 2b are set to the same opening degree. Thereafter, the newly set LEV 2a and LEV 2b are maintained until a predetermined time elapses.

  When the control means 40 determines that one of TdSHa and TdSHb is smaller than the predetermined value (step S107; No), the control means 40 determines whether TdSHa is larger than the predetermined value and whether TdSHb is smaller than the predetermined value ( Step S108). When the control means 40 determines that TdSHa is larger than the predetermined value and TdSHb is smaller than the predetermined value (step S108; Yes), LEV2a is set to the value of LEV2, and LEV2b is set to the correction value β from LEV2. (LEV2b = LEV2-β) is set (step S111).

  In this case, it can be determined that the refrigerant flow rate is biased toward the main circuit B because the refrigerant liquid amount in the accumulator 18b has increased. Therefore, the opening amount of the heat source side expansion device 15b is corrected to be smaller than the opening amount of the heat source side expansion device 15a so as to equalize the refrigerant flow rate. Thereafter, the newly set LEV 2a and LEV 2b are maintained until a predetermined time elapses. In other words, when the outside air temperature is relatively high, the air conditioner 100 compares the TdSHa and TdSHb with a predetermined value to determine the deviation of the refrigerant flow rate, and corrects the LEV2a and LEV2b as appropriate to obtain the refrigerant flow rate. This is to equalize.

  On the other hand, when the control means 40 determines that TdSHa is smaller than the predetermined value or TdSHb is larger than the predetermined value (step S108; No), TdSHa is smaller than the predetermined value and TdSHb is larger than the predetermined value. Whether or not (step S109). When the control means 40 determines that TdSHa is smaller than the predetermined value and TdSHb is larger than the predetermined value (step S109; Yes), the value obtained by subtracting the correction value β from LEV2a (LEV2a = LEV2−). β) and LEV2b is set to the value of LEV2 (step S112).

  In this case, it can be determined that the refrigerant flow rate is biased toward the main circuit A because the amount of refrigerant liquid in the accumulator 18a has increased. Therefore, the opening amount of the heat source side expansion device 15a is corrected to be smaller than the opening amount of the heat source side expansion device 15b so as to equalize the refrigerant flow rate. Thereafter, the newly set LEV 2a and LEV 2b are maintained until a predetermined time elapses. If the control means 40 determines that both TdSHa and TdSHb are smaller than a predetermined value (step S109; No), it sets LEV2a and LEV2b to values obtained by subtracting the correction value β from LEV2 (step S113).

  In this case, it can be determined that there is no bias between the refrigerant flow rate of the main circuit A and the refrigerant flow rate of the main circuit B, but the air conditioner 100 as a whole has excess refrigerant. Therefore, both the opening degree of the heat source side expansion device 15a and the opening degree of the heat source side expansion device 15b are corrected to be small to adjust the refrigerant flow rate. Thereafter, the newly set LEV 2a and LEV 2b are maintained until a predetermined time elapses.

  As described above, when the outside air temperature is lower than the reference temperature value, the air conditioner 100 determines the deviation of the refrigerant flow rate based on the opening of the bypass expansion device 21a and the opening of the bypass expansion device 21b. When the outside air temperature is higher than the reference temperature value, the deviation of the refrigerant flow rate is determined based on the degree of superheat of the refrigerant discharged from the compressor 11a and the compressor 11b. In addition, since the refrigerant flow rate correction process can be performed before either the accumulator 18a or the accumulator 18b overflows, excessive liquid back to the compressor 11a and the compressor 11b can be prevented.

  The correction value α and the correction value β shown here may be determined based on various conditions such as the horsepower, the application, and the installation location of the air conditioner 100, and the numerical values are not particularly limited. The correction value α and the correction value β may be changed and set according to various conditions of the air conditioner 100. Further, the predetermined value to be compared with TdSHa and TdSHb may be determined based on various conditions such as the horsepower, the application, and the installation location of the air conditioner 100, and is not particularly limited. The predetermined value to be compared with TdSHa and TdSHb may be changed and set according to various conditions of the air conditioner 100.

  FIG. 5 is an explanatory diagram for explaining deviation correction in the case where deviation occurs in the refrigerant flow rate. FIG. 5 (a) shows the correction of bias in the case where the refrigerant is circulated through the injection circuit, that is, low outside air heating operation, and FIG. 5 (b) shows the case where the refrigerant is not circulated through the injection circuit, that is, the outside air temperature is The bias correction during heating operation when the temperature is relatively high is shown. Based on FIG. 5, the characteristic items will be mainly described while supplementing the refrigerant flow rate deviation correction processing described in FIG. 4.

  In FIG. 5A, the refrigerant flow rate deviation in the case where the refrigerant is circulated through the injection circuit (step S103 shown in FIG. 4; Yes to step S106), the opening degree (LEV1a) of the bypass expansion device 21a and the bypass are shown. This is determined by comparing the opening degree (LEV1b) of the diaphragm device 21b. As shown in FIG. 5A, when the amount of liquid refrigerant in the accumulator 18a or the compressor 11a is large, the opening degree of the bypass expansion device 21a is smaller than the opening degree of the bypass expansion device 21b. (Step S104 shown in FIG. 4; Yes).

  That is, when the accumulator 18a is likely to overflow or the amount of liquid back to the compressor 11a is increased, the refrigerant sucked into the compressor 11a of the main circuit A becomes wet and does not inject into the compressor 11a. However, since the temperature of the discharged refrigerant decreases, it can be seen that the refrigerant flow rate is biased in the main circuit A. Therefore, in order to correct this bias, the opening degree of the heat source side expansion device 15a of the main circuit A is set small and the opening degree of the heat source side expansion device 15b of the main circuit B is set large (step S105 shown in FIG. 4). The refrigerant flow rate in the main circuit B is increased to equalize the refrigerant flow rate.

  On the other hand, as shown in FIG. 5A, when the amount of refrigerant liquid in the accumulator 18b or the compressor 11b is large, the opening degree of the bypass throttling device 21b is smaller than the opening degree of the bypass throttling device 21a. (Step S104 shown in FIG. 4; No). That is, when the accumulator 18b is likely to overflow or the amount of liquid back to the compressor 11a is increased, the refrigerant sucked into the compressor 11b of the main circuit B becomes wet and does not inject into the compressor 11b. However, it can be seen that the refrigerant flow rate is biased in the main circuit B because the temperature of the discharged refrigerant is lowered. Therefore, in order to correct this bias, the opening degree of the heat source side expansion device 15a of the main circuit A is set large and the opening degree of the heat source side expansion device 15b of the main circuit B is set small (step S106 shown in FIG. 4). The refrigerant flow rate in the main circuit A is increased to equalize the refrigerant flow rate.

  In FIG. 5B, the refrigerant flow rate deviation in the case where no refrigerant is circulated in the injection circuit (step S103; No to step S113 shown in FIG. 4) is expressed as refrigerant discharge SH (TdSHA) discharged from the compressor 11a. ) And the refrigerant discharge SH (TdSHb) discharged from the compressor 11b. That is, when the refrigerant is not circulated through the injection circuit, since the bypass expansion device 21a and the bypass expansion device 21b are in the closed state, the TdSHa and TdSHb are compared so that the flow rate of the refrigerant is biased. Judgment.

  As shown in FIG. 5B, when the amount of refrigerant liquid in the accumulator 18a or the compressor 11a is large, the refrigerant sucked into the compressor 11a of the main circuit A becomes wet, and the temperature of the discharged refrigerant is In order to decrease, TdSHa also decreases (step S109 shown in FIG. 4; Yes). Therefore, in order to correct this deviation, the opening degree of the heat source side expansion device 15a of the main circuit A is set small and the opening degree of the heat source side expansion device 15b of the main circuit B is set large (step S112 shown in FIG. 4), The refrigerant flow rate in the main circuit B is increased to equalize the refrigerant flow rate.

  On the other hand, as shown in FIG. 5B, when the amount of refrigerant liquid in the accumulator 18b or the compressor 11b is large, the refrigerant sucked into the compressor 11b in the main circuit B becomes wet, and the refrigerant discharged Since temperature falls, TdSHb also becomes low (step S108 shown in FIG. 4; Yes). Therefore, in order to correct this deviation, the opening degree of the heat source side expansion device 15a of the main circuit A is set large and the opening degree of the heat source side expansion device 15b of the main circuit B is set small (step S111 shown in FIG. 4). The refrigerant flow rate in the main circuit A is increased to equalize the refrigerant flow rate.

  In this embodiment, the case where one load-side unit 50 is mounted on the air conditioner 100 has been described as an example, but the present invention is not limited to this. For example, a plurality of heat source side units 50 may be mounted on the air conditioner 100. In the embodiment, the case where the control means 40 performs each control has been described as an example. However, the control means 40 may be mounted for each heat source side unit, and one control means 40 may be installed on the heat source side. The entire unit may be controlled in an integrated manner.

  The air conditioning apparatus 100 can be applied to a refrigeration apparatus, a room air conditioner, a packaged air conditioner, a refrigerator, a humidifier, a humidity control apparatus, a heat pump water heater, and the like. Therefore, the number of refrigerants to be used and the number of load-side units 50 may be determined according to the purpose and application to which the air conditioner 100 is applied. Moreover, the control means 40 is good to comprise with the microcomputer etc. which can control the whole air conditioning apparatus 100 whole.

3 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of the air-conditioning apparatus according to Embodiment 1. FIG. It is a Mollier diagram (PH diagram) showing a refrigerant state of heating operation at the time of low outside air. It is explanatory drawing for demonstrating the flow volume of the refrigerant | coolant made to inject. It is a flowchart which shows the flow of the deviation correction process of a refrigerant | coolant flow rate. It is explanatory drawing for demonstrating deviation correction when deviation arises in a refrigerant | coolant flow rate.

Explanation of symbols

  1 liquid piping, 2 gas piping, 3a discharge temperature sensor, 3b discharge temperature sensor, 4a injection temperature sensor, 4b injection temperature sensor, 5a high pressure side pressure sensor, 5b high pressure side pressure sensor, 6a refrigerant pressure sensor, 6b refrigerant pressure sensor, 7a Low pressure side pressure sensor, 7b Low pressure side pressure sensor, 10a Heat source side unit, 10b Heat source side unit, 11a Compressor, 11b Compressor, 12a Oil separator, 12b Oil separator, 13a Four-way valve, 13b Four-way valve, 14a Heat source Side heat exchanger, 14b Heat source side heat exchanger, 15a Heat source side throttle device, 15b Heat source side throttle device, 16a Refrigerant heat exchanger, 16b Refrigerant heat exchanger, 17a Capillary tube, 17b Capillary tube, 18a Accumulator, 18b Accumulator, 20a Injection Tube, 20b Suction pipe, 21a bypass throttle device, 21b bypass throttle device, 22a on-off valve, 22b on-off valve, 23a on-off valve (first on-off valve), 23b on-off valve (first on-off valve), 40 control means, 50 load side Unit, 51 load side expansion device, 52 load side heat exchanger, 100 air conditioner, A main circuit, B main circuit.

Claims (6)

One or more load-side units composed of a load-side heat exchanger and a load-side expansion device;
An injection pipe comprising a compressor, a flow path switching valve, a refrigerant heat exchanger, a heat source side expansion device, and a heat source side exchanger, and having a refrigerant pipe branched between the refrigerant heat exchanger and the load side expansion device An air conditioner that connects a bypass expansion device, the refrigerant heat exchanger, the first on-off valve, and two or more heat source side units that form an injection circuit in which the injection ports of the compressor are sequentially connected,
When the outside air temperature is lower than a predetermined reference temperature value, control means is provided for controlling the first on-off valve and the bypass throttling device in an open state in accordance with the flow rate of the refrigerant, and causing the refrigerant to conduct to the injection pipe. ,
The control means includes
By comparing the opening degree of each bypass expansion device of the two or more heat source side units, the amount of liquid back of the refrigerant to each compressor is judged, and the deviation of the flow rate of liquid refrigerant to each compressor is corrected. An air conditioner characterized by that. One or more load-side units composed of a load-side heat exchanger and a load-side expansion device;
An injection system comprising a compressor, a flow path switching valve, a refrigerant heat exchanger, a heat source side expansion device, a heat source side exchanger, and an accumulator, in which refrigerant piping is branched between the refrigerant heat exchanger and the load side expansion device An air conditioner in which a bypass throttling device, a refrigerant heat exchanger, a first on-off valve, and two or more heat source side units forming an injection circuit in which an injection port of the compressor is sequentially connected by a pipe are connected. ,
When the outside air temperature is lower than a predetermined reference temperature value, control means is provided for controlling the first on-off valve and the bypass throttling device in an open state in accordance with the flow rate of the refrigerant, and causing the refrigerant to conduct to the injection pipe. ,
The control means includes
By comparing the opening degree of each bypass expansion device of the two or more heat source side units, the amount of liquid back to the accumulator is judged, and the deviation of the liquid refrigerant flow rate to each accumulator is corrected. An air conditioner characterized. The control means includes
3. The air conditioner according to claim 1, wherein an opening degree of the heat source side expansion device having the larger liquid back amount is set to be small to correct a deviation of a liquid refrigerant flow rate. The control means includes
If the outside air temperature is higher than the predetermined reference temperature value,
A superheat degree that is a difference between a discharge temperature of refrigerant discharged from each compressor of the two or more heat source side units and a saturation temperature of the discharge pressure is calculated, and the superheat degree is set in advance and a predetermined value The air conditioner according to claim 1 or 2, wherein the liquid back amount is determined by comparison to correct a deviation in the flow rate of the liquid refrigerant. The control means includes
If any of the superheats is lower than the predetermined value,
It is determined that the amount of liquid back of the refrigerant is biased in the compressor or accumulator that has calculated the degree of superheat, and the opening degree of the heat source side expansion device of the main circuit is set to be small so that the liquid refrigerant flow rate The air conditioning apparatus according to claim 4, wherein the bias is corrected. A discharge temperature sensor for detecting the temperature of the refrigerant discharged from the compressor;
A high pressure side pressure sensor for detecting the pressure of the refrigerant,
The control means includes
The air conditioner according to claim 4 or 5, wherein the degree of superheat is calculated based on temperature information from the discharge temperature sensor and pressure information from the high pressure side pressure sensor.

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