JP2009198099A - Air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device capable of operation of making the most use of its pipe connection, while performing efficient operation of using injection. <P>SOLUTION: This air conditioner includes a heat source machine 100 having a compressor 110 capable of making a refrigerant flow in an intermediate part of a compression stroke via an injection pipe 161, a plurality of indoor units 200 and a relay machine 300, and can perform both heating/cooling operation, and includes a control means 400 for controlling opening of a heat source machine side flow control device 135 so that pressure of the refrigerant flowing out of an indoor unit side heat exchanger 210 being an evaporator becomes a target, by determining the target of the pressure of the refrigerant flowing to the heat source machine 100 by passing through the relay machine 300 from the indoor unit side heat exchanger 210 being the evaporator, when determining that the refrigerant is made to flow in the compressor 110 from an injection pipe 161, and a heat source machine side heat exchanger 131 becomes the evaporator, and at least one indoor unit side heat exchanger 210 becomes the evaporator. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an air conditioner for an electric heat pump that performs air conditioning by performing cooling and heating using a refrigeration cycle (heat pump cycle). In particular, the present invention relates to an improvement in the use of an air conditioner in which a plurality of indoor units (load-side units) can each perform heating or cooling, and further improve performance by injecting refrigerant during a compression stroke.

  For example, in an air conditioner using a refrigeration cycle (heat pump cycle), basically, a heat source unit (heat source unit, outdoor unit) having a compressor, a heat source unit side heat exchanger, etc., and a flow rate control unit (expansion valve) Etc.) and a load side unit (indoor unit) having an indoor unit side heat exchanger or the like is connected by a refrigerant pipe to constitute a refrigerant circuit for circulating the refrigerant. Then, in the indoor unit side heat exchanger, when the refrigerant evaporates and condenses, the heat, heat is released from the air in the air-conditioning target space to be heat exchanged, and the pressure, temperature, etc. related to the refrigerant in the refrigerant circuit are Air conditioning is performed while changing. Here, for example, according to the set temperature of the remote controller provided to the indoor unit and the temperature around the indoor unit, in each of the plurality of indoor units, cooling and heating are automatically determined, respectively. There is also an air conditioner that can perform heating and cooling simultaneous operation (mixed operation of cooling and heating) that can perform heating.

On the other hand, for example, in an air conditioner installed in a cold district or the like, when the temperature of outdoor air (hereinafter referred to as outside air) is low, the heating capacity (when heating is supplied to the indoor unit side by refrigerant circulation by the compressor ( In order to increase the amount of heat per hour (hereinafter referred to as the capacity including the cooling capacity), the refrigerant is caused to flow through the injection pipe (injection) into the middle of the compression stroke of the compressor provided in the heat source apparatus. (See, for example, Patent Document 1). This is to increase the capacity by increasing the density of refrigerant discharged from the compressor.
Japanese Patent Laid-Open No. 5-149634 (FIG. 1)

  As in Patent Document 1, it is possible to apply a refrigerant in the middle of the compression stroke to improve the heating capacity, even in an air conditioner capable of simultaneous cooling and heating operations. Therefore, the indoor unit that performs heating can sufficiently exhibit its ability.

  However, in order to perform injection in accordance with the heating capacity of the indoor unit that performs heating, the pressure on the upstream side of the injection pipe (corresponding to the pressure on the refrigerant outlet side of the indoor unit-side heat exchanger) is applied to the injection. It is necessary to increase it according to the flow rate of the refrigerant. Here, in an air conditioner that can be operated simultaneously with cooling and heating, there may be an indoor unit that performs cooling at the same time. If the heating capacity is increased in accordance with the indoor unit that is heating, the pressure of the refrigerant on the refrigerant outlet side of the indoor unit side heat exchanger that serves as the evaporator also increases in the indoor unit that performs cooling, Since a pressure difference becomes small, the cooling capacity supplied to the indoor unit which is performing cooling will fall.

  Therefore, the present invention is an air conditioner capable of simultaneous cooling and heating operation capable of supplying refrigerant to the compressor by injection, while performing efficient operation using injection and further utilizing the pipe connection. An object is to obtain a device capable of performing the above.

  An air conditioner according to the present invention includes a compressor capable of causing a refrigerant flowing through an injection pipe to flow into an intermediate portion of a compression stroke and discharging the compressor, a heat source side heat exchanger performing heat exchange between the outside air and the refrigerant, and a heat source A heat source unit having a unit-side flow control device and a four-way switching valve, a plurality of indoor units having an indoor unit-side heat exchanger and an indoor unit-side flow control unit for performing heat exchange between air to be air-conditioned and a refrigerant, and a heat source unit And a plurality of indoor units connected to a relay unit that forms a flow path for supplying a gaseous refrigerant to an indoor unit performing a heating operation and supplying a liquid refrigerant to an indoor unit performing a cooling operation An air conditioner capable of operating in a mixed heating and cooling configuration that constitutes a refrigerant circuit, wherein the refrigerant flows into the compressor from the injection pipe, the heat source side heat exchanger serves as an evaporator, and at least one indoor unit Indoor unit side heat exchanger If it is determined that the cooling operation is performed as an evaporator, a relay device is connected from the indoor unit side heat exchanger that is the evaporator in order to ensure the ability to supply the indoor unit that is performing the cooling operation. The target of the pressure of the refrigerant passing through and flowing to the heat source unit is determined, and the opening degree of the heat source unit side flow control device is controlled so that the pressure of the refrigerant flowing out from the indoor unit side heat exchanger as the evaporator becomes the target. Control means for performing processing.

  According to the present invention, the refrigerant flows into the compressor from the injection pipe, the heat source unit side heat exchanger serves as an evaporator, and the indoor unit side heat exchanger of at least one indoor unit serves as an evaporator. Heat source unit side flow control so that the control means has the determined target pressure of the refrigerant flowing out from the indoor unit side heat exchanger as the evaporator when performing the heating main operation that performs cooling Since the opening degree of the device is controlled, the heating capacity to be supplied to the indoor unit that is heating is ensured (maintained) by flowing the refrigerant from the injection pipe to the compressor, and then the evaporator and By controlling the pressure of the refrigerant flowing out from the indoor unit-side heat exchanger, it is possible to ensure (maintain) the cooling capacity supplied to the indoor unit that is performing cooling.

Embodiments of the present invention will be described below.
Embodiment 1 FIG.
FIG. 1 is a diagram illustrating the overall configuration of the air-conditioning apparatus according to Embodiment 1. First, based on FIG. 1, the means (apparatus) etc. which comprise an air conditioning apparatus are demonstrated. This air conditioner performs a cooling / heating operation using a refrigeration cycle (heat pump cycle) based on refrigerant circulation. In particular, the air conditioning apparatus according to the present embodiment is an apparatus that can perform simultaneous cooling and heating operations in which a plurality of indoor units are mixed with cooling and heating at the same time.

  As shown in FIG. 1, the air conditioner of the present embodiment mainly includes a heat source unit (heat source unit side unit, outdoor unit) 100, a plurality of indoor units (load side units) 200a, 200b and 200c, and a relay unit 300. To do. In this Embodiment, in order to control the flow of a refrigerant | coolant, the relay machine 300 is provided between the heat-source equipment 100 and indoor unit 200a, 200b, 200c, and these apparatuses are connected by piping with various refrigerant | coolant piping. In addition, the plurality of indoor units (load side units) 200a, 200b, and 200c are connected in parallel to each other. Note that, for example, in the indoor units 200a, 200b, and 200c, when there is no need to particularly distinguish or specify, the subscripts a, b, and c are hereinafter omitted.

  Regarding the pipe connection, the heat source device 100 and the relay device 300 are connected by the second main tube 20 and the first main tube 10 having a pipe diameter larger than that of the second main tube 20. In the second main pipe 20, a high-pressure refrigerant flows from the heat source device 100 side to the relay device 300 side. Further, in the first main pipe 10, a refrigerant having a lower pressure than the refrigerant flowing in the second main pipe 20 flows from the relay device 300 side to the heat source device 100 side. Here, the level of the pressure is not determined by the relationship with the reference pressure (numerical value), but by the pressurization of the compressor 110, the control of the open / close state (opening) of each flow control device, or the like. In the refrigerant circuit, it is expressed based on relative height (including the middle) (hereinafter the same. Basically, the pressure of the refrigerant discharged from the compressor 110 is the highest, and the flow rate control device Etc., the pressure of the refrigerant sucked into the compressor 110 is the lowest).

  On the other hand, the repeater 300 and the indoor unit 200a are connected by the second branch pipe 40a and the first branch pipe 30a. Similarly, the repeater 300 and the indoor unit 200b are connected by the second branch pipe 40b and the first branch pipe 30b, and the repeater 300 and the indoor unit c are connected by the second branch pipe 40c and the first branch pipe 30c. . By connecting the first main pipe 10, the second main pipe 20, the second branch pipe 40 (40a, 40b, 40c) and the first branch pipe 30 (30a, 30b, 30c), the heat source unit 100, the relay unit 300, and the indoor unit The refrigerant circulates between 200 (200a, 200b, 200c) to constitute a refrigerant circuit.

  The heat source device 100 of the present embodiment includes a compressor 110, a four-way switching valve 120, a heat source device side heat exchange unit 130, an accumulator 140, a heat source device side check valve unit 150, and an injection unit 160.

  The compressor 110 of the heat source apparatus 100 applies pressure to the sucked refrigerant and discharges (sends out) it. Here, it is assumed that the compressor 110 of the present embodiment has a two-stage configuration of a low-stage compressor 110a and a high-stage compressor 110b. The low-stage compressor 110a and the high-stage compressor 110b can arbitrarily change the drive frequency based on an instruction from the control means 400 by an inverter circuit (not shown). For this reason, the compressor 110 is an inverter compressor that can change the discharge capacity (the discharge amount of the refrigerant per unit time) and the capacity according to the discharge capacity as a whole. In addition, an injection port (not shown) for allowing the high-stage compressor 110b to suck the refrigerant flowing from the injection pipe 161 in the middle of the compression stroke between the low-stage compressor 110a and the high-stage compressor 110b. Z). For this reason, for example, when the refrigerant sucked by the low-stage compressor 110a decreases in a low outside air environment, the refrigerant can be compensated by flowing in through the injection port, and the discharge capacity can be increased. It is possible to prevent a decrease in capacity for supplying to the indoor unit that is being performed.

  The four-way switching valve 120 switches the valve corresponding to the cooling / heating mode (mode) based on the instruction of the control means 400 so that the refrigerant path is switched. In the present embodiment, the cooling only operation (herein, it means that all the indoor units being operated are cooling), the cooling main operation (cooling is the main among the simultaneous cooling and heating operations), and , The route is switched depending on the heating operation (here, all the indoor units in operation are heating) and the heating main operation (heating is the main among the simultaneous cooling and heating operations). Like that.

  The heat source machine side heat exchanger 130 includes a heat source machine side heat exchanger 131 (131a, 131b), a heat source machine side first electromagnetic on-off valve 132 (132a, 132b), and a heat source machine side second electromagnetic on-off valve 133 (133a, 133b). ), A heat source machine side blower 134, a heat source machine side flow rate control device 135, a heat exchanger bypass pipe 136, and a heat source machine side third electromagnetic on-off valve 137.

  The heat source unit side heat exchanger 131 (131a, 131b) has a heat transfer tube through which the refrigerant passes and fins (not shown) for increasing the heat transfer area between the refrigerant flowing through the heat transfer tube and the outside air. The heat exchange between the refrigerant and air (outside air) is performed. For example, it functions as an evaporator during the heating only operation or during the heating main operation, and evaporates and evaporates the refrigerant. On the other hand, during the cooling only operation or the cooling main operation, it functions as a condenser and condenses and liquefies the refrigerant. In some cases, for example, during the cooling main operation, the gas is not completely gasified or liquefied, but is condensed to a state of two-phase mixing of liquid and gas (gas) (gas-liquid two-phase refrigerant). May be performed. Here, in the present embodiment, the heat source unit side heat exchange unit 130 includes two heat source unit side heat exchangers 131a and 131b. Although the heat transfer area in the fins of the heat source machine side heat exchanger 131a and the heat source machine side heat exchanger 131b may be made different from each other, the performance related to heat exchange may be made different. It is assumed that the performance relating to the heat exchange between the heat exchanger 131a and the heat source device side heat exchanger 131b is the same.

  Further, the heat source machine side first electromagnetic on / off valve 132 (132a, 132b) and the heat source machine side second electromagnetic on / off valve 133 (133a, 133b) are opened and closed based on an instruction from the control means 400, and the heat source machine side heat exchanger The refrigerant inflow / outflow to / from 131 (131a, 131b) is controlled. For example, either the heat source machine side first electromagnetic on-off valve 132a (heat source machine side second electromagnetic on / off valve 133a) or the heat source machine side first electromagnetic on / off valve 132b (heat source machine side second electromagnetic on / off valve 133b) is closed. . This prevents the refrigerant from flowing into one of the heat source machine side heat exchangers 131a and 131b so that heat cannot be exchanged, and heat exchange as a whole of the heat source machine side heat exchange unit 130 (heat source machine side heat exchanger 131) is performed. The capacity (amount of heat related to heat exchange) can be reduced.

  And the heat source side air blower 134 for performing heat exchange with a refrigerant | coolant and air efficiently is provided in the vicinity of the heat source side heat exchanger 131. The heat source device side blower 134 can change the air volume based on an instruction from the control means 400, and the heat exchange capacity in the heat source device side heat exchanger 131 can also be changed by this air volume change. Further, the heat source apparatus side flow rate control device 135 controls the refrigerant flow rate (the amount of refrigerant flowing per unit time) to be passed based on the instruction of the control means 400, so that the inside of the heat source apparatus side heat exchanger 131. Adjust the pressure of the refrigerant that passes through.

  Furthermore, it has a heat exchanger bypass pipe 136 and a heat source machine side third electromagnetic on-off valve 137 for controlling refrigerant passage through the heat exchanger bypass pipe 136. For example, by opening the heat source machine side third electromagnetic on-off valve 103, the refrigerant can be passed through the heat exchanger bypass pipe 136 without passing through the heat source machine side heat exchanger 131.

  The accumulator 140 stores excess refrigerant in the refrigerant circuit. Further, the heat source machine side check valve unit 150 includes a heat source machine side first check valve 151 to a heat source machine side fourth check valve 154. Each heat source apparatus side check valve regulates the flow of the refrigerant by preventing the refrigerant from flowing back, and makes the refrigerant circulation path constant according to the mode. The heat source machine side first check valve 151 is located on the pipe between the heat source machine side heat exchange unit 130 and the heat source machine side second main pipe 20, and is directed from the heat source machine side heat exchange unit 130 to the second main pipe 20. Allow refrigerant circulation to. The heat source machine side second check valve 152 is located on the pipe between the four-way switching valve 120 and the first main pipe 10 and allows the refrigerant to flow from the first main pipe 10 toward the four-way switching valve 120. The heat source machine side third check valve 153 is located on the pipe between the four-way switching valve 120 and the second main pipe 20 and allows the refrigerant to flow from the four-way switching valve 120 to the second main pipe 20. The heat source machine side fourth check valve 154 is located on the pipe between the heat source machine side heat exchange unit 130 and the first main pipe 10, and is a refrigerant from the first main pipe 10 to the heat source machine side heat exchanger 131. Allow distribution.

  The injection unit 160 includes an injection pipe 161, a heat source side gas-liquid separation device 162, an injection flow rate control device 163, and an injection heat exchanger 164. The injection pipe 161 is connected to the injection port, and allows the refrigerant to flow into (supply) the compressor 110 (the high-stage compressor 110b) through the injection port. The heat source side gas-liquid separation device 162 separates the refrigerant passing therethrough into a gas refrigerant and a liquid refrigerant, and basically a part of the liquid refrigerant flows to the injection flow rate control device 163 side. The injection flow rate control device 163 adjusts the flow rate of refrigerant passing through the injection pipe 161 and the pressure of the refrigerant based on an instruction from the control unit 400. The injection heat exchanger 164 is provided for exchanging heat between the refrigerant flowing toward the injection pipe 161 and the refrigerant flowing toward the heat source unit side heat exchanging section 130.

  Here, the position of the heat source machine side gas-liquid separator 162 will be described. The injection unit 160 is basically provided to allow the refrigerant to flow into the compressor 110 via the injection pipe 161 during the heating operation (during all heating operation or during heating main operation). It is desirable to provide a position that does not affect the flow of the refrigerant during operation or cooling-main operation. Therefore, in the present embodiment, the heat source machine side gas-liquid separation device 162 is provided between the heat source machine side heat exchanger 131 and the heat source machine side first check valve 151 (second main pipe 20). In this position, during cooling, high-pressure liquid refrigerant or gas-liquid two-phase refrigerant passes, but low-pressure gas refrigerant that is most susceptible to pressure loss does not pass. Therefore, the cooling capacity can be exhibited without being affected by pressure loss.

  Moreover, in this Embodiment, the heat source machine side 1st pressure detector 170 used as the pressure sensor for detecting the pressure of the refrigerant | coolant which concerns on discharge is attached to piping connected with the discharge side of the compressor 110. FIG. Based on the signal from the heat source unit side first pressure detector 170, the control unit 400 detects, for example, the pressure Pd and temperature Td of the refrigerant discharged from the compressor 110 and calculates the condensation temperature Tc and the like based on the pressure Pd. Do. Further, a heat source unit side second pressure detector 171 for detecting the pressure of the refrigerant flowing from the relay unit 300 (indoor unit 200) side is attached on the pipe connecting the heat source unit 100 and the first main pipe 10. Then, an outside air temperature detector 172 for detecting the outside air temperature (outside air temperature) is attached.

  Next, the repeater 300 of this Embodiment is comprised with the repeater side gas-liquid separation apparatus 310, the 1st branch part 320, the 2nd branch part 330, and the repeater side heat exchange part 340. The repeater side gas-liquid separation device 310 separates the refrigerant flowing from the second main pipe 20 into a gas refrigerant and a liquid refrigerant. A gas phase part (not shown) from which the gas refrigerant flows out is connected to the first branch part 320. On the other hand, the liquid phase part (not shown) from which the liquid refrigerant flows is connected to the second branch part 330 via the relay-side heat exchange part 340.

  The 1st branch part 320 has the three-way switching valve 321 (321a, 321b, 321c) which has three ports. For each three-way switching valve 321, the first port is connected to each first branch pipe 30. Further, the second port is connected to the first main pipe 10, and the third port is connected to the gas phase part side of the repeater side gas-liquid separation device 310. The three-way switching valve 321 allows the refrigerant to flow from the indoor unit 200 side to the first main pipe 10 side based on an instruction from the control unit 400, or allows the refrigerant to flow from the relay unit side gas-liquid separator 310 side to the indoor unit 200 side. Switch the valve to flow.

  The 2nd branch part 330 has the relay machine side 1st check valve 331 (331a, 331b, 331c) and the relay machine side 2nd check valve 332 (332a, 332b, 332c). The repeater side first check valve 331 and the repeater side second check valve 332 are in an inverse parallel relationship, and one end of each is connected to the second branch pipe 40 (40a, 40b, 40c). To do. When the refrigerant flows from the indoor unit 200 side to the relay unit side heat exchange unit 340 side, the refrigerant passes through the relay unit side first check valve 331 and the relay unit side second bypass pipe 346 of the relay unit side heat exchange unit 340. Flowing into. Further, when the refrigerant flows from the repeater side heat exchange section 340 side to the indoor unit 200 side, it passes through the repeater side second check valve 332.

  The repeater-side heat exchange unit 340 includes a repeater-side first flow rate control device 341, a repeater-side first bypass pipe 342, a repeater-side second flow rate control device 343, a repeater-side second heat exchanger 344, a repeater Side first heat exchanger 345 and repeater side second bypass pipe 346 are provided.

  The relay-unit-side heat exchanging unit 340 supercools the liquid refrigerant and supplies it to the indoor unit 200 side, for example, during the cooling only operation. In addition, a pipe connection is made between the first main pipe 10, and the refrigerant that has flowed from the indoor unit 200 side and the refrigerant used for supercooling are caused to flow through the first main pipe 10. The repeater-side first flow rate control device 341 is provided between the repeater-side first heat exchanger 345 and the repeater-side second heat exchanger 344, and controls the opening degree based on an instruction from the control means 400. The refrigerant flow rate and the refrigerant pressure flowing from the repeater side gas-liquid separator 310 are adjusted. On the other hand, the relay-device-side second flow rate control device 343 controls the opening degree based on an instruction from the control unit 400, and adjusts the refrigerant flow rate and the refrigerant pressure of the refrigerant passing through the relay-device-side first bypass pipe 342. Here, the opening degree of the repeater side second flow rate control device 343 of the present embodiment is based on the difference in pressure detected by the repeater side first pressure detector 350 and the repeater side second pressure detector 351. It is assumed that the control means 400 decides. The refrigerant that has passed through the relay-side second flow rate control device 343 and the relay-side first bypass pipe 342 supercools the refrigerant in, for example, the relay-side second heat exchanger 344 and the relay-side first heat exchanger 345. The first main pipe 10 flows.

  The relay-side second heat exchanger 344 is a refrigerant in a downstream portion of the relay-side second flow control device 343 that flows through the relay-side first bypass pipe 342 (refrigerant that has passed through the relay-side second flow control device 343). And heat exchange with the refrigerant flowing from the relay-side first flow control device 341. Further, the relay-side first heat exchanger 345 includes the refrigerant that has passed through the relay-side first bypass pipe 342 and the relay-side second heat exchanger 344 and the relay-side gas-liquid separator 310 to the relay-side first heat exchanger 345. Heat exchange is performed with the refrigerant flowing through the one flow rate controller 341.

  Furthermore, the relay-unit-side second bypass pipe 346 flows the refrigerant from the indoor unit 200 that has passed through the relay-device-side first check valve 331. The refrigerant that has passed through the relay-side second bypass pipe 346 is, for example, in the cooling-main operation or heating-main operation, for example, after passing through the relay-side second heat exchanger 344 and partially or entirely performing cooling. It flows into the machine 200. Further, for example, when the all-heating operation is performed, the whole passes through the relay-unit-side second flow rate control device 343 and the relay-device-side first bypass pipe 342 and flows to the first main pipe 10.

  Further, in the relay 300, the relay-side first flow control device 341 and the relay-side gas-liquid separation device 310 are connected to detect the refrigerant pressure before and after passing through the relay-side first flow control device 341. The relay side first pressure detector 350 is attached to the pipe side. In addition, a relay-side second pressure detector 351 is attached to the pipe side connecting the second branch part 330. As described above, based on the pressure difference detected by the repeater side first pressure detector 350 and the repeater side second pressure detector 351, the control unit 400 opens the repeater side second flow rate control device 343. Determine the degree and give instructions. Further, a relay-side temperature detector 352 is attached to a pipe connecting the first main pipe 10 and the relay-side first heat exchanger 345. Based on the signal from the repeater side temperature detector 352, for example, the control means 400 determines the pressure of the refrigerant flowing from the indoor unit 200 side to the first main pipe 10 side by calculation or the like.

  Next, the configuration of the indoor unit 200 (200a, 200b, 200c) will be described. The indoor unit 200 includes an indoor unit side heat exchanger 210 (210a, 210b, 210c), an indoor unit side flow control device 220 (220a, 220b, 220c) connected in series near the indoor unit side heat exchanger 210, and an indoor unit The machine side control means 230 (230a, 230b, 230c) is provided. Similarly to the heat source unit side heat exchanger 131 described above, the indoor unit side heat exchanger 210 serves as an evaporator during cooling and serves as a condenser during heating, and between the air and the refrigerant in the air-conditioning target space. Perform heat exchange. Moreover, the indoor unit side air blower 211 (211a, 211b, 211c) for performing the heat exchange with a refrigerant | coolant and air efficiently is provided in the vicinity of each indoor unit side heat exchanger 210.

The indoor unit side flow control device 220 functions as a pressure reducing valve and an expansion valve, and adjusts the pressure of the refrigerant passing through the indoor unit side heat exchanger 210. Here, the indoor unit side flow control device 220 of the present embodiment is assumed to be composed of, for example, an electronic expansion valve that can change the opening degree. And about the opening degree of the indoor unit side flow control apparatus 220, based on the superheat degree of the refrigerant | coolant exit side (here it becomes the 1st branch pipe 30 side) of the indoor unit side heat exchanger 210 at the time of cooling, for example, each indoor The indoor unit side control means 230 of the unit 200 determines. Moreover, it determines based on the supercooling degree of the refrigerant | coolant exit side (it becomes the 2nd branch pipe 40 side here) at the time of heating. The indoor unit side control unit 230 controls the operation of each unit of the indoor unit 200. In addition, signals including various data are communicated with the control unit 400 by wire or wireless to perform processing. Here, the indoor unit side control unit 230 includes, for example, a storage unit (not shown), and the size (heat transfer area and the like) of the indoor unit side heat exchanger 210 and the air volume by the indoor unit side blower 211 The data of the heat exchange capacity at the time of cooling operation or heating operation determined by the above is stored (the size of the indoor unit side heat exchanger 210 is determined by each indoor unit 200. The heat exchange capacity will be different). Here, the heat exchange capacity of the indoor unit side heat exchanger 210 related to the heating operation is Q _jh, and the heat exchange capacity of the indoor unit side heat exchanger 210 related to the cooling operation is Q _jc . The indoor unit side control means 230 determines the cooling operation or the heating operation, the instructed air volume, etc. based on, for example, an instruction of an operator in the room input via a remote controller (not shown), and performs heat exchange. A signal including the capacity data is transmitted to the control means 400.

  The indoor unit side first temperature detector 240 (240a, 240b, 240c) and the indoor unit side second temperature detection are connected to the refrigerant inlet and outlet pipes in the indoor unit side heat exchanger 210 of each indoor unit 200. A container 241 (241a, 241b, 241c) is attached. Based on the difference between the temperature detected by the indoor unit side first temperature detector 240 and the temperature detected by the indoor unit side second temperature detector 241, the indoor unit side control means 230 determines the degree of superheat or the degree of supercooling, respectively. The opening degree of each indoor unit side flow control device 220 is determined by calculation.

  The control unit 400 performs, for example, determination processing based on signals transmitted from various detectors (sensors) provided inside and outside the air conditioner, and each device (means) of the air conditioner. And it has a function which operates each apparatus based on the judgment and carries out overall control of the whole operation | movement of an air conditioning apparatus. Specifically, the drive frequency control of the compressor 110, the opening control of the flow control device such as the heat source device side flow control device 135, the open / close control of the on / off valve such as the heat source device side first electromagnetic on / off valve 132, the four-way switching valve 120, switching control of the three-way switching valve 321 and the like. The storage unit 410 temporarily or long-term stores various data, programs, and the like necessary for the control unit 400 to perform processing. Here, in the present embodiment, the control unit 400 and the storage unit 410 are provided independently of the heat source unit 100, but are often provided in the heat source unit 100, for example. In addition, the control unit 400 and the storage unit 410 are provided in the vicinity of the apparatus. For example, the control unit 400 and the storage unit 410 may be remotely controlled by performing signal communication via a public telecommunications network or the like.

  As described above, the air conditioning apparatus of the present embodiment configured as described above performs the operation in any one of the four modes (modes) of the cooling only operation, the heating only operation, the cooling main operation, and the heating main operation. be able to. Here, the heat source device side heat exchanger 131 of the heat source device 100 functions as a condenser during the cooling only operation and the cooling main operation, and functions as an evaporator during the heating only operation and the heating main operation. Next, basic operation of each device and refrigerant flow in the operation of each embodiment will be described.

  FIG. 2 is a diagram illustrating the refrigerant flow during the cooling only operation according to the first embodiment. First, the operation of each device and the flow of refrigerant in the cooling only operation will be described with reference to FIG. The refrigerant flow in the cooling only operation is indicated by solid line arrows in FIG. Here, a case where all the indoor units 200 are performing cooling without stopping will be described. Further, the control means 400 is in a state in which the heat source machine side first electromagnetic on / off valves 132a and 132b and the heat source machine side second electromagnetic on / off valves 133a and 133b are opened, and in a state in which the heat source machine side third electromagnetic on / off valve 137 is closed. It is assumed that both the heat source apparatus side heat exchangers 131a and 131b perform heat exchange (the same applies in the description of the flow of each mode).

  In the heat source device 100, the compressor 110 compresses the sucked refrigerant and discharges the high-pressure gas refrigerant. The refrigerant discharged from the compressor 110 flows through the four-way switching valve 120 to the heat source device side heat exchanger 131. The high-pressure gas refrigerant is condensed by heat exchange with the outside air while passing through the heat source machine side heat exchanger 131, becomes a high pressure liquid refrigerant, and flows through the heat source machine side first check valve 151 (relationship of refrigerant pressure). The heat source machine side third check valve 153 and the heat source machine side fourth check valve 154 side do not flow). Then, the high-pressure liquid refrigerant flows into the repeater 300 through the second main pipe 20.

  The relay-side gas-liquid separator 310 separates the refrigerant that has flowed into the relay 300 into a gas refrigerant and a liquid refrigerant. Here, the refrigerant flowing into the relay device 300 during the cooling only operation is a liquid refrigerant, and the control unit 400 switches and controls the three-way switching valve 321 of the first branching section 320. To the indoor unit 200 (200a, 200b, 200c) side, no gas refrigerant flows. On the other hand, the liquid refrigerant passes through the relay-side first heat exchanger 345, the relay-side first flow control device 341, and the relay-side second heat exchanger 344, and a part thereof flows into the second branch section 330. To do. The refrigerant that has flowed into the second branch section 330 is divided into the indoor units 200a, 200b, and 200c via the relay-device-side second check valves 332a, 332b, and 332c and the second branch pipes 40a, 40b, and 40c.

  In the indoor units 200a, 200b, and 200c, the indoor unit flow control devices 220a, 220b, and 220c adjust the pressure and adjust the pressure of the liquid refrigerant that has flowed from the second branch pipes 40a, 40b, and 40c, respectively. Here, as described above, the opening adjustment of each indoor unit side flow control device 22 is performed based on the degree of superheat on the refrigerant outlet side of each indoor unit side heat exchanger 210. Refrigerant that has become low-pressure liquid refrigerant or gas-liquid two-phase refrigerant by adjusting the opening degree of each indoor unit side flow rate control device 220a, 220b, 220c flows to the indoor unit side heat exchangers 210a, 210b, 210c, respectively. The low-pressure liquid refrigerant or gas-liquid two-phase refrigerant evaporates by heat exchange with the indoor air that is the air-conditioning target space while passing through the indoor unit side heat exchangers 210a, 210b, and 210c. And it becomes a low-pressure gas refrigerant and flows into the 1st branch pipes 30a, 30b, and 30c, respectively. At this time, the room air is cooled by heat exchange to cool the room. Although the gas refrigerant is used here, for example, when the air conditioning load in each indoor unit 200 (the amount of heat required by the indoor unit; hereinafter referred to as load) is small, or in a transient state such as immediately after the start, the indoor unit In the side heat exchangers 210a, 210b, and 210c, the gas-liquid two-phase refrigerant may flow without being completely vaporized. The low-pressure gas refrigerant or gas-liquid two-phase refrigerant (low-pressure refrigerant) flowing from the first branch pipes 30a, 30b, 30c passes through the three-way switching valves 321a, 321b, 321c and flows to the first main pipe 10.

  The refrigerant that has passed through the first main pipe 10 and has flowed to the heat source device 100 is circulated by returning to the compressor 110 again via the heat source device side second check valve 152, the four-way switching valve 120, and the accumulator 140. This is the refrigerant circulation path during the cooling only operation.

  Here, the flow of the refrigerant in the repeater side heat exchange unit 340 will be described. As described above, the liquid refrigerant separated by the repeater side gas-liquid separation device 310 passes through the repeater side first heat exchanger 345, the repeater side first flow control device 341, and the repeater side second heat exchanger 344. Then, a part flows into the second branch part 330. On the other hand, the refrigerant that has not flowed to the second branch portion 330 side passes through the relay-device-side second flow rate control device 343. Then, the refrigerant passes through the relay-side first bypass pipe 342 and supercools the refrigerant flowing from the relay-side gas-liquid separator 310 in the relay-side second heat exchanger 344 and the relay-side first heat exchanger 345. , Flows into the first main pipe 10. By subcooling the refrigerant and flowing it to the second branch part 330 side, the enthalpy on the refrigerant inlet side (here, the second branch pipe 40 side) is reduced, and in the indoor unit side heat exchangers 210a, 210b, 210c, The amount of heat exchange with air can be increased. Here, if the opening degree of the relay-side second flow rate control device 343 is large and the amount of refrigerant (refrigerant used for supercooling) flowing through the relay-side first bypass pipe 342 increases, the amount of refrigerant that is not evaporated increases. For this reason, the gas-liquid two-phase refrigerant flows into the heat source unit 100 via the first main pipe 10.

  FIG. 3 is a diagram illustrating the refrigerant flow in the cooling-main operation. Here, the case where the indoor units 200a and 200b perform cooling and the indoor unit 200c performs heating will be described. The refrigerant flow in the cooling-main operation is indicated by solid line arrows in FIG. The operation performed by each device of the heat source apparatus 100 and the flow of the refrigerant are the same as in the cooling only operation described with reference to FIG. However, here, it is assumed that the refrigerant flowing into the relay 300 through the second main pipe 20 becomes a gas-liquid two-phase refrigerant by controlling the condensation of the refrigerant in the heat source apparatus side heat exchanger 131.

  Further, the flow of the refrigerant from the indoor units 200a and 200b in which cooling is performed, through the first main pipe 10 and into the heat source unit 100, is the same as the flow in the all cooling operation described with reference to FIG. Since it is the same, description is abbreviate | omitted. On the other hand, the refrigerant flow related to the indoor unit 200c that performs heating is different from the indoor units 200a and 200b that perform cooling. First, the gas-liquid two-phase refrigerant that has flowed into the repeater 300 is separated into a gas refrigerant and a liquid refrigerant by the repeater-side gas-liquid separator 310. The control unit 400 prevents the gas refrigerant from flowing through the three-way switching valves 321a and 321b of the first branch section 320 to the indoor units 200a and 200b. On the other hand, the three-way switching valve 321c is caused to cause a gas refrigerant to flow to the indoor unit 200c side via the first branch pipe 30c.

  In the indoor unit 200c, the pressure of the refrigerant flowing in the indoor unit side heat exchanger 210c is adjusted with respect to the refrigerant flowing from the first branch pipe 30c by adjusting the opening degree of the indoor unit side flow control device 220c. The high-pressure gas refrigerant is condensed by heat exchange while passing through the indoor unit side heat exchanger 210c, and passes through the indoor unit side flow control device 220c. At this time, the room air is heated by heat exchange to heat the room. The refrigerant that has passed through the indoor unit side flow control device 220c becomes liquid refrigerant with a slight decrease in pressure, and flows through the relay unit side second bypass pipe 346 via the second branch pipe 40c and the relay unit side first check valve 331c. . Then, it merges with the liquid refrigerant flowing from the relay-side gas-liquid separator 310, flows to the indoor units 200a and 200b, and is used as a refrigerant for cooling.

  Thus, in the cooling main operation, the heat source unit side heat exchanger 131 of the heat source unit 100 functions as a condenser. The refrigerant that has passed through the indoor unit 200 that performs heating (here, the indoor unit 200c) is used as a refrigerant for the indoor unit 200 that performs cooling (here, the indoor units 200a and 200b). Here, when the load on the indoor units 200a and 200b is small and the refrigerant flowing through the indoor units 200a and 200b is suppressed, the control unit 400 increases the opening degree of the relay-unit-side second flow rate control device 343. . Thereby, even if it does not supply the refrigerant | coolant more than necessary to the indoor units 200a and 200b which are cooling, it can flow to the 1st main pipe 10 via the relay machine side 1st bypass piping 342.

  FIG. 4 is a diagram illustrating the refrigerant flow during the heating only operation according to the first embodiment. Next, the operation of each device and the flow of refrigerant in the heating only operation will be described. Here, the case where all the indoor units 200 are heating without stopping will be described. The flow of the refrigerant in the all heating operation is indicated by solid line arrows in FIG. In the heat source device 100, the compressor 110 compresses the sucked refrigerant and discharges the high-pressure gas refrigerant. The refrigerant discharged from the compressor 110 flows through the four-way switching valve 120 and the heat source machine side third check valve 153 (the heat source machine side second check valve 152 and the heat source machine side first check valve due to the refrigerant pressure). 151 does not flow to the 151 side) and flows into the repeater 300 through the second main pipe 20.

  The refrigerant flowing into the repeater 300 is separated into a gas refrigerant and a liquid refrigerant by the repeater side gas-liquid separation device 310 and flows to the first branch section 320. Here, in the 1st branch part 320, it diverts to all the indoor units 200a, 200b, 200c via the 1st branch pipes 30a, 30b, 30c from the three-way switching valve 321 (321a, 321b, 321c).

  In the indoor units 200a, 200b, and 200c, the indoor unit side flow control devices 220a, 220b, and 220c each adjust the opening degree. Thereby, the pressure of the refrigerant flowing in the indoor unit side heat exchangers 210a, 210b, and 210c is adjusted for the refrigerant that has flowed from the first branch pipes 30a, 30b, and 30c, respectively. The high-pressure gas refrigerant is condensed by heat exchange while passing through the indoor unit side heat exchangers 210a, 210b, 210c, and passes through the indoor unit side flow control devices 220a, 220b, 220c. At this time, the indoor air is heated by heat exchange to heat the air-conditioning target space (indoor). The refrigerant that has passed through the indoor unit side flow control devices 220a, 220b, and 220c becomes a low-pressure liquid refrigerant or a gas-liquid two-phase refrigerant, and the second branch pipes 40a, 40b, and 40c and the relay unit side first check valves 331a, 331b, It flows through the repeater side second bypass pipe 346 via 331c. Then, it passes through the repeater side second flow rate control device 343 and the repeater side first bypass pipe 342 and flows to the first main pipe 10. At this time, the low pressure gas-liquid two-phase refrigerant flows into the first main pipe 10 by adjusting the opening degree of the relay-side second flow control device 343.

  The refrigerant that has flowed into the heat source apparatus 100 from the first main pipe 10 passes through the heat source apparatus side fourth check valve 154 of the heat source apparatus 100 and flows into the heat source apparatus side heat exchanger 131. While passing through the heat source machine side heat exchanger 131, it evaporates by heat exchange with air and becomes a gas refrigerant. And it returns to the compressor 110 again through the four-way switching valve 120 and the accumulator 140. Circulating by discharging as described above. This is the refrigerant circulation path during the all-heating operation.

  Here, although it has been described that all the indoor units 200a, 200b, and 200c are operating in the above-described cooling operation and heating operation, some of the indoor units may be stopped, for example. Further, for example, when some of the indoor units 200 are stopped and the load of the entire air conditioner is small, the change in the discharge capacity according to the change in the driving frequency of the low-stage compressor 110a and the high-stage compressor 110b or any It is also possible to change the supply capability by stopping one of them. In some cases, for example, the heat source machine side first electromagnetic on-off valve 132 (132, 132b), the heat source machine side second electromagnetic on / off valve 133 (133, 133b), etc., for example, the heat source machine side heat exchanger 131 (131a, The refrigerant inflow in 131b) may be controlled to change the heat exchange capacity.

  FIG. 5 is a diagram illustrating the flow of refrigerant during heating-main operation. Here, the case where the indoor units 200a and 200b perform heating and the indoor unit 200c performs cooling will be described. The flow of the refrigerant in the cooling main operation is indicated by solid line arrows in FIG. Since the operation of each device of the heat source apparatus 100 and the flow of the refrigerant are the same as those in the heating only operation described with reference to FIG.

  Moreover, about the flow of the refrigerant | coolant in the heating of indoor unit 200a, 200b, since it is the same as that of the flow at the time of the heating operation demonstrated using FIG. 4, description is abbreviate | omitted. On the other hand, the indoor unit 20c performs cooling, and the refrigerant flow differs from the indoor units 200a and 200b that perform heating. In the indoor units 200a and 200b, the refrigerant condensed by heat exchange while passing through the indoor unit side heat exchangers 210a and 210b is the indoor unit side flow rate control devices 220a and 220b, the relay unit side first check valve 331a. 331b flows to the repeater side second bypass pipe 346. Here, the control unit 400 shuts off the refrigerant flow with the relay-side gas-liquid separation device 310 by closing the relay-side first flow rate control device 341. Therefore, the condensed refrigerant passes through the relay-device-side second check valve 332c and the second branch pipe 40c, flows into the indoor unit 200c, and becomes a refrigerant used for cooling. At this time, the relay-unit-side second flow rate control device 343 is adjusted, and the control unit 400 controls the relay-device-side first heat exchanger 345 to adjust the opening degree, and supplies the refrigerant necessary for the indoor unit 200c. Meanwhile, the remaining refrigerant flows through the first main pipe 10 via the relay-side first bypass pipe 342.

  In the heating-main operation, the refrigerant that has flowed out of the indoor units that are heating (here, the indoor units 20a and 20b) flows through the indoor unit that performs cooling (here, the indoor unit 20c). Therefore, when the indoor unit 200 that performs cooling stops, the amount of the gas-liquid two-phase refrigerant that flows through the relay-side first bypass pipe 342 increases. On the contrary, when the load in the indoor unit 200 that performs cooling increases, the amount of the gas-liquid two-phase refrigerant flowing through the repeater-side first bypass pipe 342 decreases. Therefore, the load of the indoor unit side heat exchanger 210 (evaporator) in the indoor unit 200 that performs cooling changes without changing the amount of refrigerant necessary for the indoor unit 200 that performs heating.

  FIG. 6 is a diagram showing a flowchart for performing control in the heating only operation or the heating main operation of the present invention. First, based on the signal transmitted from the outside air temperature detector 172, the control unit 400 determines whether or not the outside air temperature is lower than a predetermined outside air temperature (low outside air determination) (STEP 1).

  FIG. 7 is a diagram showing the relationship between the outside air temperature, the heating capacity, and the discharge superheat degree TdSH. When the outside air temperature decreases, the pressure in the heat source apparatus side heat exchanger 131 serving as an evaporator (pressure on the suction side of the compressor 110) decreases. Therefore, the refrigerant sucked into the compressor 110 (circulating refrigerant) decreases (refrigerant density decreases), and the temperature of the refrigerant discharged from the compressor 110 increases. For example, in FIG. 7, when the refrigerant is not supplied by injection to the compressor 110 and the discharge superheat degree TdSH is 50 ° C., as shown by the thick line, the piping of the refrigerant circuit when the outside air temperature becomes lower than 0 ° C. Since the pressure of the refrigerant in the whole is lowered, the heating capacity is lowered and it is difficult to maintain 100% heating capacity. This is a characteristic tendency in an air conditioner of an electric heat pump. Therefore, the refrigerant is supplemented by injection to lower the discharge superheat degree TdSH, the pressure is maintained, and the necessary heating capacity can be ensured for all the indoor units 200 that perform heating.

  For example, the control unit 400 controls the injection flow rate control device 163 so that the target discharge superheat degree TdSH becomes 20 ° C., for example, in the case of the heating only operation using the injection for compensating the refrigerant flow shortage, Adjust the opening. At this time, as shown in FIG. 7, the heating capacity can be maintained at 100% until the outside air becomes lower than about −15 ° C.

  FIG. 8 is a diagram illustrating a relationship example between the driving frequency of the compressor 110 and the pressure loss. Moreover, as shown in FIG. 8, the pressure loss tends to increase as the drive frequency of the compressor 110 increases. For this reason, it is also effective from the viewpoint of energy efficiency to use the refrigerant supply by injection and supply the necessary capacity while lowering the drive frequency of the compressor 110 and increasing the compression ratio.

  When the control means 400 determines that the outside air temperature is not lower than a predetermined outside air temperature (for example, 0 ° C. in FIG. 7) (the outside air temperature is equal to or higher than the predetermined outside air temperature), the control unit 400 closes the injection flow rate control device 163 (closes the air flow). Leave it as it is.) Thus, the refrigerant is prevented from flowing into the injection pipe 161, and control by normal operation is performed (STEP 10).

  On the other hand, if it is determined that the outside air temperature is lower than the predetermined outside air temperature, the injection flow control device 163 is controlled (STEP 2), and the opening is adjusted so that the refrigerant flows through the injection pipe 161. Then, the refrigerant is caused to flow into the compressor 110 through the injection port.

FIG. 9 is a diagram showing the relationship between the heating capacity, the flow rate ratio, and the discharge superheat degree TdSH. 9A shows the relationship between the heating capacity and the target of the discharge superheat degree TdSH (hereinafter referred to as the target discharge superheat degree), and FIG. 9B shows the relationship between the flow rate ratio and the discharge superheat degree TdSH. Here, the heating capacity represents the sum (ΣQ _jh ) of the heat exchange capacities related to the indoor unit side heat exchangers 210 in all the indoor units 200 that perform heating. The flow rate ratio represents the ratio of the refrigerant flow rate passing through the injection pipe 161 to the refrigerant flow rate flowing through the heat source unit side heat exchange unit 130. Therefore, the flow rate ratio increases as the refrigerant flow rate passing through the injection pipe 161 increases. Such a relationship as shown in FIG. 9 is stored in the storage means 410 as data.

As shown in FIG. 9 (b), when the flow rate of the refrigerant flowing through the injection pipe 161 increases, the efficiency related to the operation decreases. However, when the heating capacity is required (when the heating capacity ΣQ _jh is large), the efficiency is reduced. Since priority is given to supplying capability at the expense, the target discharge superheat degree is small, and the flow rate of the refrigerant flowing through the injection pipe 161 is increased. On the other hand, when the heating capacity ΣQ _jh is small, priority is given to efficiency, so the target discharge superheat degree is large, and the flow rate of refrigerant flowing through the injection pipe 161 is reduced.

Based on the signal including the heat exchange capacity data (Q _jh during heating operation and Q _jc during cooling operation) transmitted from the indoor unit side control means 230 of each indoor unit 200, the control unit 400 The state of 200 is judged and the indoor unit 200 which is heating is judged. Then, the heating capacity is calculated, and the target discharge superheat degree is determined based on the data stored in the storage unit 410. And the control means 400 controls the opening degree of the injection flow control apparatus 163 so that it may become the determined target discharge superheat degree. In addition, the drive frequency of the compressor 110 is also controlled.

FIG. 10 is a diagram showing a flowchart relating to the opening degree control process of the injection flow rate control device 163. The control means 400 detects (determines) the pressure Pd and the temperature Td of the refrigerant discharged from the compressor 110 based on the detection by the heat source device side first pressure detector 170 (STEP 21). Further, the condensation temperature Tc is calculated based on the pressure Pd, and the discharge superheat degree TdSH that is the difference between the temperature Td and the condensation temperature Tc is calculated (STEP 22). Further, the target opening difference ΔLEV1 of the injection flow control device 163 is calculated based on the following equation (1) (STEP 23). Here, TdSH _m represents the target discharge superheat degree. K is a constant.
ΔLEV1 = k (TdSH−TdSH _m ) (1)

Then, based on the calculated ΔLEV1, the next opening degree target LEV1 _m of the injection flow control device 163 is calculated based on the following equation (2) (STEP 24). Here, LEV1 is the current opening target.
LEV1 _m = LEV1 + ΔLEV1 (2)

  The above processing is repeated every predetermined time (STEP 25), and the control means 400 controls the flow rate of the refrigerant flowing through the injection pipe 161 by controlling the opening degree of the injection flow control device 163.

  Furthermore, based on the signal transmitted from each indoor unit 200, the presence / absence of the indoor unit 200 performing cooling is determined (STEP 3). If it is determined that there is no air-conditioning indoor unit 200, it is determined that the heating operation is performed, and the heating operation is performed by circulating the refrigerant as described above (STEP 4). At this time, the refrigerant in the path from the indoor unit side flow control device 220 through the relay device side second bypass pipe 346, the relay device side first bypass pipe 342, and the first main pipe 10 to the heat source device side flow control device 135 The opening degree of the heat source apparatus side flow control device 135 is adjusted (STEP 6) so that the pressure (hereinafter referred to as intermediate pressure) becomes a predetermined pressure (STEP 5). This predetermined pressure is determined based on the flow rate of the refrigerant for injection.

On the other hand, if it is determined that there is at least one indoor unit 200 that is performing cooling, it is determined that the heating-main operation is performed (STEP 7). Based on the relay-side temperature detector 352 and the ratio between the heating capacity and the cooling capacity, the target intermediate pressure necessary to prevent and maintain the cooling capacity is determined (STEP 8). Here, the cooling capacity represents the sum (ΣQ _jc ) of the heat exchange capacities of the indoor unit side heat exchangers 210 in all the indoor units 200 that are performing cooling. The opening degree of the heat source device side flow control device 135 is adjusted (STEP 6) so that the pressure related to the signal from the relay side temperature detector 352 becomes the determined target intermediate pressure (STEP 9).

FIG. 11 is a flowchart illustrating a control process related to intermediate pressure during heating-main operation. This process is performed by the control unit 400. For example, the control unit 400 calculates the heating capacity ΣQ _jh at regular time intervals (STEP 31). Then, it is determined whether or not the heating capacity ΣQ _jh has changed (STEP 32). If it is determined that the heating capacity ΣQ _jh has changed, the target intermediate pressure P _mo is calculated based on the following equation (3) (STEP 33). Here, P _m represents an intermediate pressure applied to the detection by the relay-side temperature detector 352, and k ₂ represents a constant set in advance by performing a test or the like. Here, in the heating main operation, since the driving frequency of the compressor 110 changes depending on the heating capacity, the equation (3) is based on the heat exchange capacity Q _jh . Further, since the pipe friction loss and the like are proportional to the square of the refrigerant flow rate, the heat exchange capacity Q _jh is also squared in the equation (3).
P _mo = P _m −k ₂ Σ (Q _jh ) ² (3)

Further, the target opening difference ΔLEV2 of the heat source device side flow control device 135 is calculated based on the following equation (4) (STEP 34). Here, P _1m represents the current intermediate pressure, and k ₁ represents a constant set in advance by performing a test or the like.
ΔLEV2 = k ₁ (P _mo −P _1m ) (4)

Then, based on the calculated ΔLEV2, the opening degree LEV2 of the heat source device side flow control device 135 is calculated based on the following equation (5) (STEP 35). Here, LEV2 is the current opening.
LEV2 = LEV2 + ΔLEV2 (5)

  By repeating the above processing, the control means 400 controls the intermediate pressure by controlling the opening degree of the heat source unit side flow control device 135.

Figure 12 is a refrigerant flow rate Gr, the opening degree of the injection flow control device 163 LEV1 flowing injection tube 161 is a diagram representing the relationship between the intermediate pressure P _m. According to FIG. 12, the flow rate of the refrigerant flowing through the injection pipe 161 increases as the opening degree of the injection flow control device 163 increases and / or as the intermediate pressure controlled by the opening control of the heat source apparatus side flow control device 135 increases. Represents that.

  FIG. 13 is a diagram illustrating the relationship between the outside air temperature and the refrigerant temperature in the indoor unit 200 that performs cooling (the low pressure side of the relay unit 300). For example, when the outside air temperature decreases, the temperature of the liquid refrigerant tends to decrease. Therefore, if the temperature of the refrigerant in the indoor unit 200 that flows into the cooling sometimes falls below 0 ° C., the pipe will freeze. If the heating capacity can be supplied by injection, the temperature of the liquid refrigerant can be prevented from becoming 0 ° C. or less, and the refrigerant can be prevented from freezing.

  However, if the heating capacity is supplied, the intermediate pressure increases, and therefore, the excessive supply of the heating capacity changes the liquid pipe temperature (evaporation temperature) in the indoor unit 200 that is performing the cooling operation, thereby reducing the cooling capacity. Therefore, the target intermediate pressure may be determined after taking into account the determination of the target intermediate pressure as described above in order to prevent and maintain the cooling capacity. In FIG. 13, 10 ° C. is defined as a boundary example of insufficient cooling capacity, but is not limited to this value.

  As described above, according to the first embodiment, in the air conditioning apparatus capable of simultaneous cooling and heating operation including the compressor 110 that can supply the refrigerant from the injection port via the injection pipe 161, particularly the heating main body When the operation is performed, when the outside air temperature is low, injection is performed to supply the refrigerant to the compressor 110, and the control unit 400 is configured to supply heating capacity and cooling capacity while sufficiently supplying the heating capacity. Based on the ratio and the outside air temperature, a target intermediate pressure that is within a range that does not impair the cooling capability of the indoor unit 200 that performs cooling is determined, and the heat source unit side flow control device 135 is set so as to be the target intermediate pressure. Since the intermediate pressure control is performed by adjusting the opening degree, the necessary capacity is supplied to the indoor unit 200 that performs cooling in the heating-main operation, It is possible to equity. At this time, since the target discharge superheat degree in the compressor 110 is determined based on the heating capacity in the indoor unit 200 that performs heating, and the opening degree of the injection flow control device 163 is controlled, heating is performed. A sufficient capacity can be supplied to the indoor unit 200 as well.

Embodiment 2. FIG.
As described above, the control means 400 is often provided in the heat source apparatus 100. In such a case, the amount of communication with the repeater 300 and the indoor unit 200 can be reduced by performing signal communication with a device (means) provided in the heat source device 100. For example, if the state of the relay unit 300 and the indoor unit 200 can be determined based on a signal transmitted from a detector provided in the heat source unit 100, signal communication between the relay unit 300 and the indoor unit 200 is possible. There is no need to do.

  FIG. 14 is a diagram illustrating a relationship example between the heat source unit side intermediate pressure unit and the drive frequency of the compressor 110. Here, the pressure in the heat source device side intermediate pressure part is the pressure of the refrigerant related to the detection by the heat source device side second pressure detector 171. Further, the pressure in the relay unit-side low pressure portion shown in FIG. 14 is the pressure of the refrigerant that passes through the first main pipe 10 and tends to flow toward the heat source device 100, and is detected by the relay-device-side temperature detector 352. Pressure is based on temperature. For example, when the heating main operation is performed, the pressure is also the pressure on the refrigerant outlet side of the indoor unit side heat exchanger 210 of the indoor unit 200 performing the cooling.

  Ideally, the pressure in the low pressure section on the repeater side and the pressure in the intermediate pressure section on the heat source machine side are the same, but in reality, pressure loss occurs in the piping, etc. The pressure in the intermediate pressure part is different. Further, as shown in FIG. 8 described above, the pressure loss increases as the drive frequency of the compressor 110 increases. Therefore, as shown in FIG. 10, the pressure at the heat source device side intermediate pressure portion decreases and deviates from the pressure at the relay device side low pressure portion. The relationship between the heat source machine side intermediate pressure section as shown in FIG. 10 and the drive frequency of the compressor 110 differs depending on, for example, the length of the pipe. Here, for example, a pressure loss also occurs in the second main pipe 20, but the influence of the pressure loss is particularly large when the refrigerant pressure is low. Therefore, the refrigerant pressure before and after passing through the first main pipe 10 is greater than the second main pipe 20. It is affected by the refrigerant pressure before and after passing.

  Therefore, in the present embodiment, the control unit 400 determines the relay frequency on the repeater side, the heat source side intermediate pressure unit, and the drive frequency of the compressor 110 as shown in FIG. A relationship is derived and stored in the storage means 410 as data. Then, the control means 400 determines the target intermediate pressure in the first embodiment based on the heat source device side second pressure detector 171 instead of performing the determination based on the pressure based on the temperature detected by the relay device side temperature detector 352. And the driving frequency of the compressor 110 (the discharge amount of the compressor 110).

Next, an example of a process for determining the relationship between the relay machine-side low pressure part and the heat source machine-side intermediate pressure part will be described. For example, the intermediate pressure P _m (pressure of the low pressure portion of the repeater side) related to the detection of the relay side temperature detector 352 and the intermediate of the heat source side related to the detection of the heat source side second pressure detector 171 at a plurality of driving frequencies F. The pressure P ₁ of the pressure part is determined and stored in the storage means 410. Here, when n = 1 to 4, data of P _m and P ₁ at each driving frequency F of 30 × n (30, 60, 90, 120) Hz are stored in the storage unit 410.

And in each section, for example, 30-60 Hz, 60-90 Hz, etc., ΔP _m which becomes the pressure (P _m −P ₁ ) lost between the intermediate pressure P _m and the pressure P ₁ of the heat source machine side intermediate pressure part With respect to the relationship with the drive frequency F, an interpolation equation is derived by interpolation, and the equation is stored in the storage unit 410. Here, for example, when linear interpolation is performed, the interpolation formula of ΔP _m in each section is represented by a linear function of the drive frequency F. Since P _m = P ₁ + ΔP _m , if the pressure P ₁ and the drive frequency F are known, the intermediate pressure P _m can be determined. From the intermediate pressure P _m , the target intermediate pressure P _mo can be calculated based on the equation (3). Here, after calculating the intermediate pressure P _m , the target intermediate pressure P _mo is calculated based on the equation (3). For example, as described above, the drive frequency F of the compressor 110 depends on the heating capacity. Therefore, by interpolating the target intermediate pressure P _mo shown in the equation (3) in an interpolation manner, the target intermediate pressure P _mo is directly calculated from the drive frequency F based on the interpolation equation. Also good.

  For example, this processing may be determined when the air conditioner is installed. For example, during heating-main operation, a predetermined number of data is stored in the storage unit 410 at a predetermined timing, and then an interpolation formula is derived. It may be. In addition, communication may be performed so as not to cause a communication load between the relay device 300 and the indoor unit 200, and an interpolation formula may be marched based on the data.

Here, the driving frequency of the compressor 110, the pressure Pd of the refrigerant compressor 110 is discharged is determined to be the target pressure Pd _m. On the other hand, as described above, the flow rate of the refrigerant flowing through the injection pipe 161 is controlled by the opening degree target LEV1 calculated based on the target discharge superheat degree TdSH, and the refrigerant discharge state of the compressor 110 is controlled to be constant. Therefore, the driving frequency of the compressor 110 and the discharge amount are associated with each other via the pressure Pd. If the driving frequency of the compressor 110 is determined, the discharge amount of the compressor 110 is also uniquely determined.

  Further, the control unit 400 thereafter uses the indoor unit side heat exchanger of the indoor unit 200 that performs cooling based on the pressure detected by the signal from the heat source unit side second pressure detector 171, for example, in the heating main operation. The pressure on the refrigerant outlet side of 210 is determined. And based on the determination, in order to make the determined target intermediate pressure, control of the heat source unit side flow control device 135 is performed.

  Thereby, it is not necessary to receive a signal from the repeater side temperature detector 352 by communication with the repeater 300 side, and the indoor unit 200 that performs cooling while heating is mainly operated while reducing the communication amount. The pressure on the refrigerant outlet side of the indoor unit side heat exchanger 210 can be adjusted to ensure the cooling capacity.

  Here, although application at the time of heating main operation is explained, it is not limited only to heating main operation. For example, during the cooling main operation, the determination based on the pressure detected by the signal from the heat source device side second pressure detector 171 may be performed.

Embodiment 3 FIG.
FIG. 15 is a diagram illustrating the relationship between the cooling capacity and the heating capacity. When the heating-main operation is performed, if the ratio of the cooling capacity that functions as an evaporator increases with respect to the heating capacity, the ratio of the gas refrigerant in the gas-liquid two-phase refrigerant that flows in through the first main pipe 10 increases. Become.

  On the other hand, the heat source apparatus side heat exchanger 131 can function as an evaporator even in heating-main operation, but if the ratio of the cooling capacity increases and the ratio of the gas refrigerant increases, if the refrigerant can be circulated, the heat source apparatus The operation can be continued even if the side heat exchanger 131 does not evaporate the refrigerant by heat exchange. Further, in the heat source machine side heat exchanger 131, since the evaporation temperature of the low-pressure refrigerant is lower than the outside air temperature, for example, when the refrigerant is passed through the heat source machine side heat exchanger 131 in a state where the outside air temperature is low, Water vapor freezes in the heat source unit side heat exchanger 131 and is likely to be frosted.

  Therefore, in the heating-main operation, the control unit 400 determines that the outside air temperature is equal to or lower than a predetermined temperature based on the detection by the outside air temperature detector 172, and the ratio between the heating capacity and the cooling capacity is determined in advance. If it is determined that it is greater than or equal to the range (the shaded area in FIG. 15), the injection flow control device 163 is controlled to be opened. Then, the liquid refrigerant separated by the heat source device side gas-liquid separation device 162 passes through the injection pipe 161 and is sucked into the high stage compressor 110b through the injection port. Thereby, a path through which the liquid refrigerant circulates through the injection pipe 161 is formed. On the other hand, the heat source side third electromagnetic on-off valve 137 is controlled to be opened, and the gas refrigerant that has passed through the heat exchanger bypass pipe 136 is sucked into the low stage compressor 110a. Then, the electromagnetic open / close valves provided before and after the indoor unit side heat exchangers 131a, 131b (heat source unit side second electromagnetic open / close valves 133a, 133b, heat source unit side first electromagnetic open / close valves 132a, 132b) are closed. For this reason, the refrigerant does not pass through the heat source device side heat exchanger 131 and heat exchange is not performed in the heat source device side heat exchanger 131. Therefore, it does not frost.

  In this way, the refrigerant is allowed to pass through the injection pipe 161 and the heat exchanger bypass pipe 136 to secure a circulation path, and the refrigerant is prevented from passing through the heat source unit side heat exchanger 131, so that It can suppress that the frost which concerns on water vapor | steam arrives at the heat source apparatus side heat exchanger 131. FIG. Therefore, the frequency of defrosting (defrosting) can be reduced, driving efficiency can be increased, and comfort can be improved.

Embodiment 4 FIG.
FIG. 16 is a diagram illustrating a configuration of an air-conditioning apparatus according to Embodiment 4 of the present invention. In FIG. 16, the same reference numerals as those in the first embodiment perform the same operation, and thus the description thereof is omitted. In FIG. 13, the defrost bypass pipe 180 is a refrigerant that connects the refrigerant pipe on the discharge side of the compressor 110 (the high-stage compressor 110 b), the heat source apparatus side flow control device 135, and the heat source apparatus side heat exchanger 131. It is a pipe that connects the pipe. The defrost bypass pipe 180 becomes a part of a defrost bypass circuit that is different from the refrigerant circuit that performs the simultaneous cooling and heating operation when the heat source apparatus side heat exchanger 131 is defrosted. The heat source side defrosting electromagnetic on-off valve 181 adjusts the passage of the refrigerant in the defrosting bypass pipe 180 by opening and closing. The air conditioner of the present embodiment is an air conditioner that can be operated simultaneously with cooling and heating, including the compressor 110 provided with an injection port, as in the first embodiment. Therefore, the above-described injection pipe 161 is used as a part of the refrigerant circuit so that defrosting of the heat source unit side heat exchanger 131 can be performed simultaneously with simultaneous cooling and heating operation.

  In addition, in order to detect the temperature of the refrigerant before and after passing through the heat source unit side heat exchanger 131, the pipe side connecting the heat source unit side heat exchange unit 130 and the four-way switching valve 120 (during heating operation or heating main operation). The heat source machine side second temperature detector 174 is attached to the refrigerant outlet side. Further, the heat source side second temperature detector 174 is attached to the pipe side (the refrigerant outlet side during the cooling only operation or the cooling main operation) connecting the defrost bypass pipe 180 and the heat source side heat exchanger 131.

  Here, the flow of the refrigerant that performs defrosting of the heat source apparatus side heat exchanger 131 while performing the heating main operation will be described. First, defrosting operation on the heat source device 100 side will be described. When starting the defrost operation, the control means 400 controls the opening degree of the heat source unit side flow control device 135 to close it (sets the opening degree to 0), and opens the heat source unit side defrosting electromagnetic on-off valve 181. The refrigerant can pass through the defrost bypass pipe 180.

  In this state, a heat source provided to allow a part of the high-temperature and high-pressure gas refrigerant discharged from the high-stage compressor 110b to pass through the defrost bypass pipe 180 and immediately bypass a sufficient amount of refrigerant. The machine-side defrost electromagnetic on-off valve 181 becomes a high-temperature / low-pressure refrigerant and flows into a pipe connecting the heat source machine side flow control device 135 and the heat source machine side heat exchanger 131. Since the heat source apparatus side flow control device 135 is closed, the refrigerant flows to the heat source apparatus side heat exchanger 131 side. The flowing refrigerant passes through the heat source apparatus side heat exchanger 131. At this time, heat exchange is performed between the frost adhering to the heat source apparatus side heat exchanger 131 and the refrigerant, the frost is melted, and defrosting is performed. On the other hand, the refrigerant having a low temperature and a low pressure due to heat exchange with frost is sucked into the low-stage compressor 110a through the four-way switching valve 120 and the accumulator 140.

  Of the refrigerant discharged from the high-stage compressor 110b, the refrigerant that has not flown into the defrost bypass pipe 180 is connected to the repeater 300 and the indoor unit through the same refrigerant path as in the heating-main operation described in the first embodiment. 200 is passed. Here, based on the instruction of the control means 400, the relay unit is set so that the dryness of the intermediate-pressure gas-liquid two-phase refrigerant that has passed through the relay unit-side second flow rate control device 343 is about 0.1 to 0.2. The second side flow rate control device 343 controls the opening degree. Here, for example, when the ratio of the cooling capacity to the heating capacity is 0.9 or more, for example, the refrigerant flowing through the relay-side second flow control device 343 is about 10% of the total. On the other hand, the other refrigerant (about 90% of the refrigerant) passes through the indoor unit 200 that performs cooling in which the indoor unit-side heat exchanger 210 functions as an evaporator. Therefore, the ratio of the gas refrigerant by evaporation is large in the indoor unit side heat exchanger 210, and the merged refrigerant becomes a gas-liquid two-phase refrigerant having a dryness of about 0.9.

  This gas-liquid two-phase refrigerant flows through the first main pipe 10 and flows into the heat source apparatus 100, and then flows through the heat source apparatus side second check valve 152 to the heat source apparatus side gas-liquid separation device 162. Here, when the injection flow control device 163 is opened, the heat source apparatus side flow control device 135 is closed, so that the refrigerant having a dryness of about 0.9 passes through the injection flow control device 163 and the injection pipe 161 and is injected. Flows into the port. And it merges with the refrigerant | coolant discharged from the low stage side compressor 110a, and flows in into the high stage side compressor 110b.

  FIG. 17 is a diagram illustrating a flowchart of processing related to defrosting in heating-main operation. In the present embodiment, based on the ratio between the heating capacity and the cooling capacity, the above-described defrost while performing the heating main operation and the defrost that is switched to the cooling main operation are performed separately.

  For example, when the heating main operation is performed in the air conditioner (STEP 41), the control unit 400 detects the heat source machine side first temperature based on the signal transmitted from the heat source machine side first temperature detector 173. It is determined whether the temperature (the temperature of the refrigerant that has passed through the heat source device side heat exchanger 131) related to the detection of the heat exchanger 173 is lower than a predetermined first defrosting temperature (STEP 42). If the temperature is lower than the first defrosting temperature, it is determined that the heat source device side heat exchanger 131 is to be defrosted on the assumption that heat exchange is not performed well due to frost.

  Next, it is determined whether or not the ratio between the heating capacity and the cooling capacity is greater than a predetermined value (STEP 43). Here, basically, if the heating capacity / cooling capacity <1, the ratio of the cooling capacity is larger, and in this case, the cooling main operation is performed. Therefore, the predetermined value is assumed to be a value of 1 or more.

  If it is determined that the ratio between the heating capacity and the cooling capacity is larger than the predetermined value, as described above, the heat source apparatus side flow control device 135 is closed and the heat source apparatus side defrosting electromagnetic on-off valve 181 is opened (STEP 44). . Then, as described above, defrosting is started while the heating main operation is continued.

  When the frost melts and heat exchange with the frost disappears, the temperature on the outlet side becomes higher during heating of the heat source device side heat exchanger 131. Therefore, based on the signal transmitted from the heat source device side first temperature detector 173, the temperature related to the detection by the heat source device side first temperature detector 173 (the temperature of the refrigerant that has passed through the heat source device side heat exchanger 131) is It is determined whether the temperature is higher than the second defrosting temperature (STEP 46). If it is determined that the temperature is higher than the second defrosting temperature, a signal related to the instruction is transmitted to the heat source device side flow control device 135 to be opened, and the heat source device side defrosting electromagnetic on-off valve 181 is closed (STEP 48). Accordingly, the refrigerant is prevented from passing through the defrost bypass pipe 180, and is passed through the heat source unit side heat exchanger 131, and the defrost operation is ended (STEP 50).

  On the other hand, when it is determined that the ratio between the heating capacity and the cooling capacity is equal to or less than the predetermined value, the four-way switching valve 120 and the like are switched to the cooling side (STEP 45), and the cooling main operation is started. As described above, when the ratio between the heating capacity and the cooling capacity decreases, the refrigerant having a large proportion of the liquid refrigerant flows into the heat source unit 100 through the first main pipe 10, so that the injection pipe 161 is used as a refrigerant circuit. It cannot be used. Therefore, in order to continue the cooling and heating simultaneous operation while performing defrosting, the four-way switching valve 120 and the like are switched to the cooling side, the cooling main operation is performed, and the high-temperature gas refrigerant directly from the compressor 110 is converted into the heat source unit side heat exchanger 131. Let it pass in. Thereby, a cooling and heating simultaneous operation is continued, performing defrost.

  Basically, in an environment where the heating capacity is larger than the cooling capacity, the cooling main operation is not originally performed. However, if the heating capacity is slightly larger than the cooling capacity, the heat source side heat exchanger 131 by defrost is used. It is possible to perform the cooling main operation after giving priority to the defrosting.

  Here, for example, the cooling capacity is smaller than the heating capacity means that in the indoor unit 200 that performs cooling, there is little refrigerant (refrigerant that evaporates into gas) that passes through the indoor unit-side heat exchanger 210, and relaying is performed. The amount of refrigerant passing through the machine-side second flow rate control device 343 increases. Therefore, the gas-liquid two-phase refrigerant having a low dryness (a large proportion of the liquid refrigerant) flows into the heat source apparatus 100 from the first main pipe 10. Here, as described above, in order to perform defrosting, the heat source apparatus side flow control device 135 is closed, and all the refrigerant from the first main pipe 10 passes through the injection pipe 161 and flows from the injection port. Become. Therefore, the amount of liquid back (liquid refrigerant is sucked into the compressor) in the high stage compressor 110b also increases. When the amount of the liquid back increases, for example, the refrigerant liquid is mixed with the refrigerating machine oil serving as the lubricating oil of the compressor 110 or the like, and the refrigerating machine oil in the compressor 110 is diluted to cause a lubrication failure or the like. Cause seizure. For this reason, in the heating-main operation, if the amount of liquid back increases, the injection pipe 161 cannot be used as a refrigerant circuit. Therefore, in consideration of the amount of liquid refrigerant passing through the injection pipe 161, depending on the case, the defrosting while continuing the heating main operation is not performed or the cooling main operation is continued by switching to the cooling main operation.

  When the frost melts and heat exchange with the frost disappears, the temperature on the outlet side during the cooling of the heat source apparatus side heat exchanger 131 increases. Therefore, based on the signal transmitted from the heat source device side second temperature detector 174, the control means 400 passes the temperature related to the detection by the heat source device side second temperature detector 174 (the heat source device side heat exchanger 131 has passed. It is determined whether the temperature of the refrigerant is higher than the third defrost temperature (STEP 47). If it is determined that the temperature of the refrigerant related to condensation is higher than the third defrost temperature, the four-way switching valve 120 or the like is switched to the heating side (STEP 49), the heating main operation is returned, and the defrost operation is terminated (STEP 50).

  The control means 400 further determines the state of each indoor unit 200 based on the signal transmitted from each indoor unit 200, and determines whether or not to continue the heating main operation (STEP 51). If it is determined that the heating main operation is to be continued, the process returns to STEP 42 to continue the above-described determination and the like. If it is determined that the heating main operation is not continued, the heating main operation is terminated (STEP 52), and a process such as shifting to another mode is performed.

  As described above, according to the air conditioner of Embodiment 4, the injection pipe 161 is used as the refrigerant circuit, and the refrigerant that has flowed in through the first main pipe 10 from the indoor unit 200 side is allowed to pass through the injection pipe 161. To return to the compressor 110 (higher stage compressor 110b). On the other hand, a part of the refrigerant discharged from the compressor 110 is passed through the defrost bypass pipe 180 and sent to the heat source machine side heat exchanger 131 to perform defrosting. The defrosting of the heat source machine side heat exchanger 131 can be performed. Therefore, the low-temperature refrigerant passes through the indoor-unit-side heat exchanger 210 of the indoor unit 200 in which the low-temperature refrigerant is heated by interruption of the operation on the indoor-unit 200 side by defrosting or heat exchange with frost. It can be prevented from being sent to the air-conditioning target space, and comfortable air-conditioning operation can be continued. Further, the control means 400 performs the defrost while continuing the cooling / heating simultaneous operation by the heating main operation based on the ratio of the heating capacity and the cooling capacity, or switches to the cooling main operation and continues the cooling / heating simultaneous operation. Try to determine what to do. Thereby, only when the amount of liquid back to the compressor 110 is appropriate as an allowable amount, the injection pipe 161 is used as a refrigerant circuit. For example, dilution of refrigerating machine oil inside the high stage compressor 110b, etc. Therefore, it is possible to prevent the seizure of the bearing, and to obtain a highly reliable air conditioner.

It is a figure showing the structure and refrigerant circuit of the air conditioning apparatus in Embodiment 1. FIG. 3 is a diagram illustrating a refrigerant flow in a cooling only operation in the first embodiment. 3 is a diagram illustrating a refrigerant flow in a cooling main operation in Embodiment 1. FIG. 3 is a diagram illustrating a refrigerant flow in a heating only operation in Embodiment 1. FIG. FIG. 3 is a diagram illustrating a refrigerant flow in heating-main operation in Embodiment 1. It is a figure showing the flowchart of the control at the time of all heating operation or heating main operation. It is a figure showing the relationship between external temperature and a heating capability. It is a figure showing the example of a relationship between the drive frequency of the compressor 110, and a pressure loss. It is a figure showing the relationship between heating capacity and target discharge superheat degree. It is a figure showing the control flowchart of the injection flow control apparatus 163. It is a figure showing the flowchart of intermediate pressure control at the time of heating main operation. It is a figure showing the relationship between the refrigerant | coolant flow volume which flows through the injection pipe | tube 161, and an intermediate pressure. It is a figure showing the relationship between external temperature and the refrigerant | coolant temperature of the indoor unit 200 which concerns on air_conditioning | cooling. It is a figure showing the example of a relationship between the heat source side intermediate pressure part and the drive frequency of the compressor. It is a figure showing the relationship between a cooling capacity | capacitance and a heating capacity | capacitance. It is a figure showing the structure and refrigerant circuit of the air conditioning apparatus in Embodiment 4. It is a figure showing the flowchart of the defrost process in heating main operation.

Explanation of symbols

  10 1st main pipe, 20 2nd main pipe, 30a, 30b, 30c 1st branch pipe, 40a, 40b, 40c 2nd branch pipe, 100 heat source machine, 110 compressor, 110a low stage side compressor, 110b high stage side compression Machine, 120 four-way switching valve, 130 heat source machine side heat exchange section, 131a, 131b heat source machine side heat exchanger, 132a, 132b heat source machine side first electromagnetic on-off valve, 133a, 133b heat source machine side second electromagnetic on-off valve, 134 Heat source machine side blower, 135 Heat source machine side flow control device, 136 Heat exchanger bypass pipe, 137 Heat source machine side third electromagnetic on-off valve, 140 Accumulator, 150 Heat source machine side check valve section, 151 Heat source machine side first check Valve, 152 heat source machine side second check valve, 153 heat source machine side third check valve, 154 heat source machine side fourth check valve, 160 injection section, 161 injection pipe 162 heat source side gas-liquid separation device, 163 injection flow control device, 164 injection heat exchanger, 170 heat source side first pressure detector, 171 heat source side second pressure detector, 172 outside air temperature detector, 173 heat source unit Side first temperature detector, 174 heat source unit side second temperature detector, 200a, 200b, 200c indoor unit, 210a, 210b, 210c indoor unit side heat exchanger, 211a, 211b, 211c indoor unit side blower, 220a, 220b , 220c Indoor unit side flow control device, 230a, 230b, 230c Indoor unit side control means, 240a, 240b, 240c Indoor unit side first temperature detector, 241a, 241b, 241c Indoor unit side second temperature detector, 300 relay 310, repeater side gas-liquid separator, 320 first branching section, 321a, 321b , 321c Three-way switching valve, 330 Second branch section, 331a, 331b, 331c Relay machine side first check valve, 332a, 332b, 332c Relay machine side second check valve, 340 Relay machine side heat exchange section, 341 Relay Machine side first flow control device, 342 relay machine side first bypass piping, 343 relay machine side second flow control device, 344 relay machine side second heat exchanger, 345 relay machine side first heat exchanger, 346 relay machine Side second bypass pipe, 350 relay machine side first pressure detector, 351 relay machine side second pressure detector, 352 relay machine side temperature detector, 400 control means, 410 storage means.

Claims (7)

Compressor capable of flowing and discharging refrigerant flowing through injection pipe into intermediate part of compression stroke, heat source side heat exchanger performing heat exchange between outside air and refrigerant, heat source side flow control device, and four-way switching valve A heat source machine having
A plurality of indoor units having an indoor unit side heat exchanger that performs heat exchange between air to be air-conditioned and a refrigerant, and an indoor unit side flow control device;
A relay device that is between the heat source unit and the plurality of indoor units and forms a flow path for supplying a gaseous refrigerant to the indoor unit that performs heating and supplying a liquid refrigerant to the indoor unit that performs cooling And an air conditioner capable of mixed cooling and heating operation that constitutes a refrigerant circuit by pipe connection,
The refrigerant flows into the compressor from the injection pipe, the heat source unit side heat exchanger serves as an evaporator, and the indoor unit side heat exchanger of at least one of the indoor units serves as an evaporator. If you determine that
The ratio of the amount of heat related to the heat exchange of the indoor unit-side heat exchanger of the indoor unit that performs the heating to the amount of heat of the indoor unit-side heat exchanger of the indoor unit that performs the cooling, and the temperature of the outside air Based on the indoor unit side heat exchanger that serves as the evaporator, and determines the target of the pressure of the refrigerant that flows through the relay unit from the indoor unit side heat exchanger that is the evaporator and flows into the heat source unit. An air conditioner comprising: control means for performing processing for controlling an opening degree of the heat source unit side flow control device so that the pressure of the refrigerant flowing out of the exchanger becomes the target. Regarding the refrigerant flowing through the relay unit to the heat source unit, the refrigerant pressure in the relay unit from the indoor unit side heat exchanger serving as the evaporator, and the refrigerant flowing through the relay unit to the heat source unit Storage means for storing in advance data relating to the pressure loss between
The control means is configured such that the pressure of the refrigerant flowing out from the indoor unit-side heat exchanger serving as the evaporator based on the pressure of the refrigerant in the heat source apparatus and the data stored in the storage means according to detection by the detection means. The air conditioning apparatus according to claim 1, wherein a process for controlling an opening degree of the heat source unit side flow control device is performed. The heat source apparatus further includes an injection flow rate control device for controlling the flow rate of the refrigerant flowing through the injection pipe,
The control means determines a target temperature of the refrigerant discharged from the compressor based on the amount of heat exchanged in the indoor unit-side heat exchanger of the indoor unit that performs the heating and the temperature of the outside air. The air conditioner according to claim 1 or 2, wherein a process for controlling the injection flow rate control device is performed based on the determined target temperature of the refrigerant discharged from the compressor. Pipe connection in parallel with the heat source machine side heat exchanger, the heat source machine further comprises a heat exchanger bypass pipe that allows only gaseous refrigerant to pass through,
When the heat source unit side heat exchanger serves as an evaporator, and the indoor unit side heat exchanger of at least one of the indoor units functions as an evaporator and performs cooling,
The control means has a predetermined ratio between a heat amount related to heat exchange of the indoor unit-side heat exchanger of the indoor unit that performs the heating and a heat amount of the indoor unit-side heat exchanger of the indoor unit that performs the cooling. The control processing is performed so as to pass a gaseous refrigerant through the heat exchanger bypass pipe and to pass a liquid refrigerant through the heat source side heat exchanger when it is determined that the refrigerant is within the range. The air conditioning apparatus in any one of 1-3. A defrost bypass pipe for branching a part of the refrigerant discharged from the compressor and passing the heat source unit side heat exchanger;
When the heat source unit side heat exchanger serves as an evaporator and the indoor unit side heat exchanger of at least one of the indoor units serves as an evaporator to perform cooling,
The control means is configured such that a ratio between a heat amount related to heat exchange of the indoor unit side heat exchanger of the indoor unit performing the heating and a heat amount of the indoor unit side heat exchanger of the indoor unit performing the cooling is a predetermined value. When it is determined that defrost due to frost formation on the heat source unit side heat exchanger is necessary, the heat source unit side flow control device is closed, and the refrigerant is passed through the defrost bypass pipe, A process of forming a circuit that circulates through the heat source unit side heat exchanger and forming a refrigerant circuit in which the refrigerant flowing from the relay unit side to the heat source unit side passes through the injection pipe and flows into the compressor The air conditioner according to any one of claims 1 to 4, wherein When the ratio between the amount of heat related to heat exchange of the indoor unit-side heat exchanger of the indoor unit that performs the heating and the amount of heat of the indoor unit-side heat exchanger of the indoor unit that performs the cooling is smaller than the predetermined value Judging
The air conditioning apparatus according to claim 5, wherein a process of switching the four-way switching valve is performed so that the heat source apparatus side heat exchanger becomes a condenser.   An injection heat exchanger that exchanges heat between the refrigerant that passes through the relay and flows to the heat source apparatus side heat exchanger and the refrigerant that flows to the injection pipe when the heat source apparatus side heat exchanger is an evaporator; Furthermore, it equips with the said heat-source equipment, The air conditioning apparatus in any one of Claims 1-6 characterized by the above-mentioned.

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