JP2008215697A - Air conditioning device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioning device free from degradation of operational efficiency of a refrigerating cycle and foreign matter recovering efficiency even in replacing a heat source-side unit and a load-side unit at a low outside air temperature. <P>SOLUTION: In this air conditioning device 100, the load-side unit 50 and the heat source-side unit 10 provided with an injection circuit are connected with each other, a liquid pipe 1 is branched between a refrigerant heat exchanger 16 and a load-side throttle device 51, an opening and closing valve 32, a foreign matter separator 31 and an opening and closing valve 33 are successively connected by a bypass pipe 30 reconnected to the liquid pipe 1 between a refrigerant heat exchanger 15 and the load-side throttle device 51 to constitute a foreign matter recovering circuit, and an opening and closing valve 24 is disposed in the liquid pipe 1 between a part branching to the bypass pipe 30 and a part reconnecting the bypass pipe 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an air conditioner that can be replaced with a new heat source side unit and a load side unit using an existing refrigerant pipe, and particularly when the air conditioner is replaced with a new heat source side unit and a load side unit, the operating efficiency of the refrigeration cycle is improved. The present invention relates to an air conditioner that improves the efficiency of collecting foreign matter in the refrigerant pipe while maintaining it.

  Conventionally, there is an air conditioner that can replace the refrigerant by using the existing refrigerant pipe as it is. Such an air conditioner simply replaces the existing heat source side unit (outdoor unit) and load side unit (indoor unit) with a new heat source side unit and load side unit, that is, replaces it with a new refrigerant pipe. No need. Therefore, the labor, cost and time required for the replacement work of the refrigerant pipe can be reduced. In addition, since the heat source side unit and the load side unit are simply replaced, significant construction of the building in which the air conditioner is installed is unnecessary, and the reliability of the air conditioner is improved.

  In addition, such an air conditioner normally collects foreign matter such as refrigeration oil remaining in the existing refrigerant pipe or its deteriorated product after replacing the heat source side unit and the load side unit. Yes. In other words, after replacing the heat source side unit and the load side unit, the operation of the air conditioner is started, and the foreign matter remaining in the refrigerant pipe is washed away with the new filled refrigerant, and the foreign matter is removed by a foreign matter catcher or the like. The air conditioner is renewed so that only the new refrigerant flows into the refrigerant pipe.

  As such, “the extension pipe and / or the use side machine used in the refrigeration cycle apparatus using the first refrigerant and the first lubricating oil, the second refrigerant and the second lubricating oil are used. In the refrigeration cycle apparatus used as the extension pipe of the refrigeration cycle apparatus and / or the use side machine, the first lubricating oil remaining in the extension pipe and / or the use side machine is continuously fed while performing the refrigeration cycle operation. A "refrigeration cycle apparatus having storage means for storing in a part of the refrigerant circuit" has been proposed (see, for example, Patent Document 1).

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

  In the refrigeration cycle apparatus described above, the collection efficiency of foreign matters has been reduced in cold regions where the outside air temperature is minus 10 ° C. (hereinafter referred to as low outside air). In such a cold district, heat exchange is performed between the outside air and the refrigerant, so that the evaporation temperature of the refrigerant is lowered and the low pressure of the refrigerant is also lowered. Therefore, the density of the refrigerant sucked into the compressor is reduced. That is, the flow rate of the refrigerant sucked into the compressor is reduced. As a result, the amount of foreign matter that can be pushed away decreases, and as a result, the collection efficiency of the foreign matter has been reduced.

  The present invention has been made in order to solve the above-described problems, so that the operating efficiency of the refrigeration cycle and the recovery efficiency of foreign matter are not reduced even if the heat source side unit and the load side unit are replaced during low outside air. An object of the present invention is to provide an air conditioning apparatus.

  An air conditioner according to the present invention includes a load side unit composed of a load side heat exchanger and a load side throttle device, a compressor, a flow path switching valve, a refrigerant heat exchanger, a heat source side throttle device, and a heat source side exchanger. An injection pipe comprising a refrigerant pipe branched between the refrigerant heat exchanger and the load side throttle device, a bypass throttle device, the refrigerant heat exchanger, a first on-off valve, and an injection port of the compressor An air conditioner connected to a heat source side unit forming an injection circuit in which the refrigerant circuits are sequentially connected, wherein the refrigerant pipe is branched between the refrigerant heat exchanger and the load side expansion device, and the refrigerant heat exchanger A foreign substance recovery circuit in which a second on-off valve, a foreign substance separator, and a third on-off valve are sequentially connected by a bypass pipe reconnected to the refrigerant pipe between the valve and the load side throttle device, and branching to the bypass pipe You A portion, characterized in that a fourth on-off valve in the refrigerant pipe between the portions to reconnect the bypass pipe.

  The air conditioner according to the present invention includes a load-side unit including a load-side heat exchanger and a load-side throttle device, a compressor, a flow path switching valve, a refrigerant heat exchanger, a heat source-side throttle device, and a heat source side. A bypass throttle device, a refrigerant heat exchanger, a first on-off valve, and a compressor configured by an injection pipe that is constituted by an exchanger and branches a refrigerant pipe between the refrigerant heat exchanger and the load side throttle device. An air conditioner connected to a heat source side unit forming an injection circuit in which injection ports are sequentially connected, wherein the refrigerant pipe is branched between the flow path switching valve and the suction port of the compressor. A foreign matter recovery circuit in which a second on-off valve, a foreign matter separator, and a third on-off valve are sequentially connected by a bypass pipe reconnected to the refrigerant pipe between the path switching valve and the suction port of the compressor; Minute to bypass pipe A portion, characterized in that a fourth on-off valve in the refrigerant pipe between the portions to reconnect the bypass pipe.

  Since the air conditioner according to the present invention includes the injection circuit and the foreign matter recovery circuit, the refrigerant flow rate can be increased even in low outside air where the coolant flow rate is low, and the heating capacity and the foreign matter recovery efficiency are reduced. You can avoid it.

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

  The air conditioner 100 is roughly composed of a heat source side unit 10 and a load side unit 50. The heat source side unit 10 and the load side unit 50 are connected and communicated by a liquid pipe 1 that is a refrigerant pipe and a gas pipe 2 that is a refrigerant pipe. Specifically, the heat source side unit 10 and the load side unit 50 are composed of a compressor 11, a four-way valve 13 as a flow path switching valve, a load side heat exchanger 52, a load side expansion device 51, a refrigerant heat exchanger 16, and a heat source. The side expansion device 15 and the heat source side exchanger 14 are connected by a main circuit which is a refrigerant circuit in which the liquid pipe 1 and the gas pipe 2 are sequentially connected. That is, the air conditioner 100 can perform the cooling operation and the heating operation by circulating the refrigerant in the main circuit.

  In the heat source side unit 10, a main refrigerant circuit, an injection circuit, and a foreign matter recovery circuit are formed. The main refrigerant circuit of the heat source side unit 10 includes a compressor 11, an oil separator 12, a four-way valve 13, a heat source side heat exchanger 14, a heat source side expansion device 15, a refrigerant heat exchanger 16, and an accumulator 18. Are sequentially connected. The compressor 11 is a type in which the number of revolutions is controlled by an inverter and the capacity is controlled. The compressor 11 sucks the refrigerant flowing through the liquid pipe 1 and compresses the refrigerant to a high temperature / high pressure state. Further, the compressor 11 has a structure capable of injecting (injecting) refrigerant supplied from an injection circuit into a compression chamber inside the compressor 11.

  The oil separation device 12 has a function of separating the refrigerator oil component from the refrigerant gas in which the refrigerator oil is mixed. The separated refrigerating machine oil is returned to the compressor 11 by controlling the flow rate by a capillary tube 17 provided in a refrigerant pipe connecting the suction side pipe connected to the compressor 11 and the oil separator 12. It has become. The four-way valve 13 switches the refrigerant flow between the cooling operation and the heating operation. The heat source side heat exchanger 14 functions as a condenser, and performs heat exchange between air supplied from a fan or the like (not shown) and the refrigerant to condense and liquefy the refrigerant.

  The heat source side expansion device 15 functions as a pressure reducing valve or an expansion valve, and decompresses the refrigerant to expand it. It is assumed that the heat source side expansion device 15 is configured by a device whose opening degree can be variably controlled, for example, an electronic expansion valve or the like. The refrigerant heat exchanger 16 exchanges heat between the refrigerant flowing through the main refrigerant circuit and the refrigerant flowing through the injection circuit. The accumulator 18 stores excess refrigerant. Due to the presence of the accumulator 18, gas-liquid separation is possible, and the dryness of the suction of the compressor can be made more than specified. In addition, the accumulator 18 should just be a container which can store an excessive refrigerant | coolant.

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

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

  The on-off valve 22 is controlled to be opened / closed by the control means 40 and may or may not conduct the refrigerant. The on-off valve 22 is installed to adjust the pressure fluctuation in the refrigeration cycle by being controlled to open and close by the control means 40. The on-off valve 23 is also controlled to be opened / closed by the control means 40 and may or may not conduct the refrigerant. That is, by opening the on-off valve 23, the refrigerant is conducted to the injection pipe 20 to form an injection circuit.

  The foreign material recovery circuit of the heat source side unit 10 is configured such that the bypass pipe 30 that branches the liquid pipe 1 between the refrigerant heat exchanger 16 and the load side expansion device 51 is connected to the refrigerant heat exchanger 16 and the load side expansion device 51. It is comprised by making it reconnect to the liquid piping 1 between. Further, the bypass pipe 30 includes two on-off valves (an on-off valve 32 as a second on-off valve and an on-off valve 33 as a third on-off valve), and a foreign matter separator 31 between the two on-off valves. It has been. Further, the liquid pipe 1 between the part where the bypass pipe 30 is branched and the part where the bypass pipe 30 is reconnected is provided with an on-off valve 24 which is a fourth on-off valve.

  The on-off valve 32 and the on-off valve 33 are controlled to be opened / closed by the control means 40 and may or may not conduct the refrigerant. By controlling the opening and closing of the on-off valve 32 and the on-off valve 33, the refrigerant can be conducted to the bypass pipe 30 and the foreign matter can be sealed in the foreign matter separator 31. The on-off valve 24 is also controlled to open / close by the control means 40 so that the refrigerant is not conducted. That is, by making the on-off valve 24 closed, the refrigerant is conducted to the bypass pipe 30 to form a foreign substance recovery circuit. The foreign matter separator 31 is for separating the foreign matter remaining in the liquid pipe 1 and the gas pipe 2 from the refrigerant.

  That is, when the heat source side unit 10 and the load side unit 50 are operated after replacement, the on-off valve 24 is closed, the refrigerant is conducted into the bypass pipe 30, and foreign matter is collected by the foreign matter separator 31. When the foreign matter collecting step is completed, the on-off valve 24 is opened and the on-off valve 32 and the on-off valve 33 are closed to separate and collect the foreign matter from the refrigeration cycle. The configuration of the foreign matter separator 31 is not particularly limited as long as foreign matter such as refrigeration oil mixed in the refrigerant can be collected. Moreover, although the case where the foreign material collection | recovery circuit is provided in the heat source side unit 10 is shown as an example, it is not limited to this. For example, the foreign substance recovery circuit may be provided in the load side unit 50 or may be provided outside the heat source side unit 10 and the load side unit 50.

  The control means 40 has a function of comprehensively controlling the entire air conditioner 100. Specifically, the control means 40 controls the drive frequency of the compressor 11, the opening degree of the heat source side expansion device 15, the bypass expansion device 21 and the load side expansion device 51, the opening / closing valve 22, the opening / closing valve 23. The on-off valve 24, the on-off valve 32, and the on-off valve 33 are controlled to open and close. Here, although the case where the control means 40 is provided in the heat source side unit 10 is described as an example, the present invention is not limited to this. For example, the control means 40 may be provided in the load side unit 50 or may be provided outside the heat source side unit 10 and the load side unit 50.

  A load side expansion device 51 and a load side heat exchanger 52 are mounted on the load side unit 50. The load side throttle device 51 functions as a pressure reducing valve or an expansion valve, and decompresses the refrigerant to expand it. It is assumed that the load side throttle device 51 is configured by a device whose opening degree can be variably controlled, for example, an electronic expansion valve. The load-side heat exchanger 52 functions as an evaporator, performs heat exchange between the refrigerant and air, and evaporates and condenses the refrigerant. In addition, in this Embodiment 1, although the case where the one load side unit 50 is mounted in the air conditioning apparatus 100 is shown as an example, it is not limited to this, You may mount multiple units.

  The gas pipe 2 is a refrigerant pipe that conducts the refrigerant that has been compressed by the compressor 11 and turned into a gas. The liquid pipe 1 is a refrigerant pipe that conducts the refrigerant that has been condensed by the load-side heat exchanger 52 to become a liquid. The injection pipe 20 and the bypass pipe 30 are also refrigerant pipes that conduct the refrigerant. The drive frequency of the compressor 11, the opening degree of the heat source side expansion device 15, the bypass expansion device 21, and the load side expansion device 51, and the opening / closing control of the on / off valve 22 and the on / off valve 23 are controlled. Means 40 is adapted to do this. That is, the control means 40 controls each device based on information sent from each temperature sensor and each pressure sensor (not shown).

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

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

Here, the update of the air conditioning apparatus 100 will be described.
First, the heat source side unit 10 and the load side unit 50 constituting the air conditioner 100 are replaced with the new heat source side unit 10 and the load side unit 50, that is, the new heat source side unit 10 and the load side unit 50 are replaced. Next, the replaced heat source side unit 10 and the load side unit 50 are connected by the existing liquid piping 1 and gas piping 2, thereby forming a refrigeration cycle. Thus, the refrigerant can be replenished or replaced only by replacing the heat source side unit 10 and the load side unit 50 with new ones.

  Thereafter, foreign matters such as refrigerating machine oil remaining in the existing liquid pipe 1 and gas pipe 2 and deteriorated products thereof are collected. That is, after replacing the heat source side unit 10 and the load side unit 50 with each other, the operation of the air conditioner 100 is started, and the foreign matter remaining in the liquid pipe 1 and the gas pipe 2 is washed away with the new sealed refrigerant. The foreign matter is collected by the foreign matter catcher 31 and the air conditioner 100 is updated so that only the refrigerant flows into the liquid pipe 1 and the gas pipe 2. In addition, the new refrigerant | coolant enclosed may be a refrigerant | coolant for replenishing the refrigerant | coolant used before replacement, and may be a refrigerant | coolant different from the refrigerant | coolant used before replacement.

  Specifically, the open / close valve 24 is closed and the open / close valve 32 and the open / close valve 33 are opened. In such a valve state, the refrigerant in which foreign matters are mixed flows into the bypass pipe 30, and after the foreign matter is collected by the foreign matter separator 31, only the refrigerant returns to the main circuit. If the operation is continued for a predetermined time in such a valve state, the foreign matters mixed in the refrigerant can be collected. Thereafter, by opening the on-off valve 24 and closing the on-off valve 32 and the on-off valve 33, foreign matter can be removed from the main circuit and sealed in the foreign matter separator 31.

Here, the operation | movement including the update of the air conditioning apparatus 100 is demonstrated.
First, the heating operation when the outside air temperature is relatively high will be described. Based on FIG. 1, the refrigerant | coolant state at the time of the heating operation of the air conditioning apparatus 100 is demonstrated. When the air conditioner 100 starts the heating operation, the compressor 11 is first driven. The high-temperature and high-pressure gas refrigerant discharged from the compressor 11 flows out from the heat source side unit 10 via the oil separator 12 and the four-way valve 13, flows through the gas pipe 2, and loads on the load side in the load side unit 50. The heat exchanger 52 is reached.

  When this high-temperature / high-pressure gas refrigerant flows through the gas pipe 2, the refrigerating machine oil and its degradation products used in the old unit (the heat source side unit and the load side unit before replacement) are pushed together with the refrigerant, and the load side The heat exchanger 52 is reached. In the load-side heat exchanger 52, the gas refrigerant is condensed and liquefied while dissipating heat to air or water, and becomes a low-temperature / high-pressure liquid refrigerant. In other words, the heating operation is performed by giving the heat stored in the refrigerant to the air or water on the load side.

  The liquid refrigerant condensed and liquefied by the load-side heat exchanger 52 is decompressed to an intermediate pressure by the load-side expansion device 51 to become an intermediate-pressure liquid refrigerant or a gas-liquid two-phase refrigerant. This intermediate-pressure liquid refrigerant or gas-liquid two-phase refrigerant flows out of the load side unit 50, flows through the liquid pipe 1, and reaches the heat source side unit 10. At this time, by opening the on-off valve 24 and closing the on-off valve 32 and the on-off valve 33, the refrigerant containing foreign matters is circulated in the foreign matter collecting circuit before reaching the heat source unit 10. . The refrigerant flows through the bypass pipe 30, returns to the liquid pipe 1 after the foreign matter is collected by the foreign matter separator 31, and reaches the heat source side unit 10.

  Here, since the outside air temperature is relatively high, the refrigerant does not flow into the injection circuit. That is, the bypass throttling device 21 and the on-off valve 23 are controlled to be closed. The on-off valve 22 may be controlled to be opened and closed so as to adjust the pressure fluctuation in the refrigeration cycle. For example, when the bypass throttling device 21 and the on-off valve 23 are closed, the on-off valve 22 may be opened to adjust the pressure fluctuation in the refrigeration cycle.

  In such a state, the refrigerant that has flowed into the heat source side unit 10 passes through the refrigerant heat exchanger 16 and is then depressurized by the heat source side expansion device 15 to become a low-pressure / low-temperature liquid refrigerant or a gas-liquid two-phase refrigerant. This refrigerant is evaporated and gasified into a gas refrigerant by exchanging heat with air in the heat source side heat exchanger 14. That is, the state changes to gas by absorbing heat from the air supplied to the heat source side heat exchanger 14. The gas refrigerant passes through the four-way valve 13 and the accumulator 18 and is then sucked into the compressor 11. The heating operation is continued for a predetermined time while maintaining such a valve state. Thereafter, the foreign matter collecting circuit can be separated from the main circuit by opening the on-off valve 24 and closing the on-off valve 32 and the on-off valve 33. That is, the foreign matter can be collected in the foreign matter separator 31 and sealed.

  In this Embodiment 1, although the case where the one heat source side unit 10 is mounted is demonstrated to the example, it does not limit to this. For example, a plurality of the heat source side units 10 may be mounted in preparation for a case where the air conditioning load required for the air conditioner 100 is large. Note that when the outside air temperature is relatively high, the refrigerant does not flow into the injection circuit, and thus the heat exchange is not performed in the refrigerant heat exchanger 16. Further, when the outside air temperature is relatively high, the flow rate of the refrigerant flowing through the main circuit does not decrease so much, and the heating operation efficiency and the foreign matter recovery efficiency do not significantly decrease.

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

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

  Further, the liquid refrigerant condensed and liquefied by the load-side heat exchanger 52 is decompressed to an intermediate pressure by the load-side expansion device 51 to become an intermediate-pressure liquid refrigerant or a gas-liquid two-phase refrigerant (state (c)). This intermediate-pressure liquid refrigerant or gas-liquid two-phase refrigerant flows out of the load side unit 50, flows through the liquid pipe 1, and reaches the heat source side unit 10. At this time, by opening the on-off valve 24 and closing the on-off valve 32 and the on-off valve 33, the refrigerant containing foreign matters is circulated in the foreign matter collecting circuit before reaching the heat source unit 10. . The refrigerant flows through the bypass pipe 30, returns to the liquid pipe 1 after the foreign matter is collected by the foreign matter separator 31, and reaches the heat source side unit 10.

  Here, since the outside air is low, a part of the refrigerant is allowed to flow into the injection circuit. Whether or not the outside air is low is determined by the control means 40 comparing the outside air temperature with a preset reference temperature value. The control means 40 controls the bypass expansion device 21 and the on-off valve 23 to be in an open state, and diverts the refrigerant that has flowed into the heat source unit 10. That is, the refrigerant flowing into the heat source side unit 10 is divided into the main refrigerant circuit and the injection circuit. In addition, when the bypass throttling device 21 and the on-off valve 23 are in the open state, the on-off valve 22 may be closed to adjust the pressure fluctuation in the refrigeration cycle.

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

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

  In the compressor 11, the refrigerant sucked through the main refrigerant circuit (state (f)) is compressed and heated to an intermediate pressure (state (i)), and then injected from the injection circuit (state (h)). ). The merged refrigerant is compressed to a high pressure (state (a)) and discharged again after the temperature is slightly lowered (state (j)). The heating operation is continued for a predetermined time while maintaining such a valve state. Thereafter, the foreign matter collecting circuit can be separated from the main circuit by opening the on-off valve 24 and closing the on-off valve 32 and the on-off valve 33. That is, the foreign matter can be collected in the foreign matter separator 31 and sealed. Note that heat exchange is performed in the refrigerant heat exchanger 16 in order to cause the refrigerant to flow into the injection circuit.

  FIG. 3 is a graph for explaining the relationship between the outside air temperature and the refrigerant flow rate. FIG. 4 is a graph for explaining the relationship between the outside air temperature and the foreign matter recovery time. Based on FIG. 3 and FIG. 4, the foreign substance recovery time when the refrigerant is circulated through the injection circuit at the time of low outside air will be described. In FIG. 3, the vertical axis indicates the refrigerant flow rate, and the horizontal axis indicates the outside air temperature. In FIG. 4, the vertical axis represents the foreign substance recovery time, and the horizontal axis represents the outside air temperature.

  In the heating operation when the outside air temperature is relatively low, heat exchange with the outside air has to be performed, so that the evaporation temperature of the refrigerant decreases, and the evaporation pressure (low pressure) decreases accordingly. And the density of the refrigerant | coolant suck | inhaled by the compressor 11 also falls. As a result, the refrigerant flow rate decreases with the outside air temperature as shown by line A in FIG. Therefore, in the refrigeration cycle that does not include the injection circuit, the density of the refrigerant sucked into the compressor is lowered, so that the refrigerant flow rate is reduced and the compression ratio is increased. That is, the capacity of the refrigeration cycle is reduced.

  In the refrigeration cycle including the injection circuit as in the air conditioner 100 according to the first embodiment, an intermediate-pressure refrigerant (state (g)) in the compression process of the compressor 11 as shown by the line B in FIG. Can be injected to increase the refrigerant flow rate (improve the density of the refrigerant). That is, the heating capacity can be maintained even in low outside air without abnormally increasing the discharge temperature from the compressor 11. Further, the efficiency when the foreign matter remaining in the liquid pipe 1 and the gas pipe 2 is washed away by the refrigerant and the amount of the foreign matter remaining in the liquid pipe 1 and the gas pipe 2 are large in the shearing force acting between the foreign matter and the refrigerant. Affected. For this reason, in the case of the low outside air and the flow rate characteristic as shown by line A in FIG. 3, the foreign matter recovery time becomes longer as the outside air temperature decreases as shown by line A in FIG. That is, the foreign substance collection efficiency is reduced.

  Therefore, in the refrigeration cycle including the injection circuit as in the air conditioner 100 according to the first embodiment, an intermediate-pressure refrigerant (state (g) in the compression process of the compressor 11 as shown by the line B in FIG. )) Can be injected to increase the flow rate of the refrigerant, so that the decrease in the flow rate of the refrigerant can be reduced, and the foreign matter collecting ability can be maintained even with low outside air. Therefore, as can be seen from FIG. 3 and FIG. 4, the air conditioning apparatus 100 according to the first embodiment includes the injection circuit, and therefore allows the refrigerant to flow through the injection circuit even in the low outside air. As a result, the foreign matter recovery ability is improved while maintaining the heating ability.

Embodiment 2.
FIG. 5 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of the air-conditioning apparatus 200 according to Embodiment 2 of the present invention. Based on FIG. 5, the circuit configuration of the air conditioning apparatus 200 will be described. The air conditioner 200 performs a cooling operation and a heating operation using a refrigeration cycle (heat pump cycle) for circulating a refrigerant. In the second embodiment, differences from the first embodiment will be mainly described, and the same parts as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

  The difference of the air conditioning apparatus 200 from the air conditioning apparatus 100 according to Embodiment 1 is the installation position of the foreign substance recovery circuit. In the foreign substance recovery circuit according to the second embodiment, the bypass pipe 30a branched from the gas pipe 2 between the four-way valve 13 and the accumulator 18 is reconnected to the gas pipe 2 between the four-way valve 13 and the accumulator 18. Is made up of. The bypass pipe 30a includes two on-off valves (an on-off valve 32a as a second on-off valve and an on-off valve 33a as a third on-off valve), and a foreign matter separator 31a between the two on-off valves. It has been. Further, the gas pipe 2 between the part where the bypass pipe 30a is branched and the part where the bypass pipe 30a is reconnected is provided with an on-off valve 24a which is a fourth on-off valve.

  Even if the foreign substance recovery circuit is arranged as described above, the same effect as that of the air-conditioning apparatus 100 according to Embodiment 1 can be obtained. Therefore, the air conditioning apparatus 200 according to Embodiment 2 can increase the refrigerant flow rate (improve the refrigerant density) without abnormally increasing the temperature of the refrigerant discharged from the compressor 11 by providing an injection circuit. It is possible to maintain the heating capability and the foreign matter recovery capability even with low outside air.

  In the first and second embodiments, the case where both the heat source side unit 10 and the load side unit 50 are replaced has been described as an example. However, the present invention is not limited to this. That is, the same effect can be obtained even when at least one of the heat source side unit 10 and the load side unit 50 is replaced. The air conditioning apparatus 100 and the air conditioning apparatus 200 can be applied to a refrigeration apparatus, a room air conditioner, a packaged air conditioner, a refrigerator, a humidifier, a humidity control apparatus, a heat pump water heater, and the like.

  Therefore, it is preferable to determine the refrigerant to be used, the number of the heat source side units 10 and the number of the load side units 50 according to the purpose and application to which the air conditioning apparatus 100 and the air conditioning apparatus 200 are applied. Moreover, the control means 40 is good to comprise with the microcomputer etc. which can control the air conditioning apparatus 100 and the air conditioning apparatus 200 whole. Further, a temperature sensor for detecting the temperature of the refrigerant discharged from the compressor 11, a pressure sensor for detecting the pressure of the refrigerant sucked into the compressor 11, and the injection pipe 20 after heat exchange with the refrigerant heat exchanger 16 are provided. A temperature sensor or the like for detecting the temperature of the flowing refrigerant may be installed.

3 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of the air-conditioning apparatus according to Embodiment 1. FIG. It is a Mollier diagram (PH diagram) showing a refrigerant state of heating operation at the time of low outside air. It is a graph for demonstrating the relationship between external temperature and a refrigerant | coolant flow rate. It is a graph for demonstrating the relationship between external temperature and foreign material collection | recovery time. 6 is a refrigerant circuit diagram illustrating a refrigerant circuit configuration of an air-conditioning apparatus according to Embodiment 2. FIG.

Explanation of symbols

  1 liquid piping, 2 gas piping, 10 heat source side unit, 11 compressor, 12 oil separator, 13 four-way valve, 14 heat source side heat exchanger, 15 heat source side expansion device, 16 refrigerant heat exchanger, 17 capillary tube, 18 accumulator , 20 Injection pipe, 21 Bypass throttling device, 22 On-off valve, 23 On-off valve (first on-off valve), 24 On-off valve (fourth on-off valve), 24a On-off valve (fourth on-off valve), 30 Bypass pipe, 30a Bypass pipe, 31 foreign matter separator, 31a foreign matter separator, 32 on-off valve (second on-off valve), 32a on-off valve (second on-off valve), 33 on-off valve (third on-off valve), 33a on-off valve (third on-off valve) Valve), 40 control means, 50 load side unit, 51 load side throttle device, 52 load side heat exchanger, 100 air conditioner, 200 air conditioner.

Claims (5)

A load-side unit composed of a load-side heat exchanger and a load-side expansion device;
An injection pipe comprising a compressor, a flow path switching valve, a refrigerant heat exchanger, a heat source side expansion device, and a heat source side exchanger, and having a refrigerant pipe branched between the refrigerant heat exchanger and the load side expansion device An air conditioner in which a bypass expansion device, the refrigerant heat exchanger, a first on-off valve, and a heat source side unit that forms an injection circuit in which the injection ports of the compressor are sequentially connected,
A bypass pipe branched from the refrigerant heat exchanger and the load side throttle device and reconnected to the refrigerant pipe between the refrigerant heat exchanger and the load side throttle device is a second pipe. An on-off valve, a foreign matter separator and a third on-off valve sequentially connected,
An air conditioner characterized in that a fourth on-off valve is provided in the refrigerant pipe between a portion branching to the bypass pipe and a portion reconnecting the bypass pipe. A load-side unit composed of a load-side heat exchanger and a load-side expansion device;
An injection pipe comprising a compressor, a flow path switching valve, a refrigerant heat exchanger, a heat source side expansion device, and a heat source side exchanger, and having a refrigerant pipe branched between the refrigerant heat exchanger and the load side expansion device An air conditioner in which a bypass expansion device, the refrigerant heat exchanger, a first on-off valve, and a heat source side unit that forms an injection circuit in which the injection ports of the compressor are sequentially connected,
A bypass pipe branched from the refrigerant switching pipe between the flow path switching valve and the compressor inlet and reconnected to the refrigerant pipe between the flow path switching valve and the compressor inlet; A foreign matter collecting circuit in which a second on-off valve, a foreign matter separator and a third on-off valve are sequentially connected;
An air conditioner characterized in that a fourth on-off valve is provided in the refrigerant pipe between a portion branching to the bypass pipe and a portion reconnecting the bypass pipe. The air conditioner according to claim 1 or 2, wherein an accumulator is provided between the flow path switching valve and the suction port of the compressor. When replacing at least one of the load side unit or the heat source side unit,
When the outside air temperature is lower than the predetermined reference temperature value,
While controlling the first on-off valve and the bypass throttling device to an open state, the refrigerant is conducted to the injection pipe,
The control means for controlling the second on-off valve and the third on-off valve to be in an open state and the fourth on-off valve to be in a closed state to allow the refrigerant to flow through the bypass pipe. An air conditioner according to claim 1. The control means includes
After a predetermined time,
The air conditioner according to claim 4, wherein the second open / close valve and the third open / close valve are closed and the fourth open / close valve is controlled open to separate the bypass pipe from the refrigerant pipe.

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