JP4104112B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner having a vapor compressor type heat pump cycle, and is particularly suitable for improving the operation efficiency and saving energy when operating at an intermediate load (intermediate capacity) or less.
[0002]
[Prior art]
Conventionally, an air conditioner provided with an injection circuit as a high-efficiency cycle for increasing the coefficient of performance of the air conditioner is known. For example, in Japanese Patent Application Laid-Open No. 10-176866, as a method for realizing an operation with a high coefficient of performance in a wide capacity range, an injection circuit is provided, and an operation with a higher coefficient of performance is selected from injection operation or non-injection operation. Is described.
[0003]
Further, as a capacity control means of the compressor, a method of extracting and bypassing the refrigerant from the compression chamber is known, and is described in, for example, Japanese Patent Application Laid-Open No. 9-256974. Further, Japanese Patent Laid-Open No. 11-351167 discloses that multi-stage capacity control is performed as a scroll compressor capable of changing a partial load operation of 50% or less to multi-stages.
[0004]
[Problems to be solved by the invention]
In the above prior art, the coefficient of performance of the air conditioner increases by using the gas injection cycle, but the effect decreases gradually as the pressure ratio decreases. That is, the effect of gas injection is great when the load is large, but the effect is small when the load is small. On the other hand, generally in an environment where an air conditioner is used, there are many cases of low and medium loads, which is not sufficient for energy saving, especially annual power saving. In addition, although the compressor capacity control according to the above-described prior art is multi-stage, the capacity control range is much narrower and the energy-saving effect is small compared to the inverter controller that is currently mainstream as an energy-saving model.
[0005]
An object of the present invention is to provide an air conditioner that improves the efficiency in accordance with the actual situation of the use environment and can operate with a high coefficient of performance (high energy saving) throughout the year.
[0006]
It is another object of the present invention to expand the operating range from a low load to a high load, that is, to further reduce the capacity even when the compressor is set to the minimum operating frequency in the inverter control model.
[0007]
Furthermore, the capacity control can be performed even in a model without inverter control, and an operation method suitable for energy saving can be selected regardless of the presence or absence of inverter control.
The present invention is to achieve at least one of the above objects.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention configured a refrigeration cycle by sequentially connecting a compressor, a heat source side heat exchanger, a first pressure reducing device, a receiver, a second pressure reducing device, and a use side heat exchanger with piping. In the air conditioner, an injection circuit that connects the receiver and a compression chamber of the compressor, a bypass circuit that connects the injection circuit and a suction side pipe of the compressor, and a compression chamber side of the compressor in the injection circuit A three-way valve that opens and closes the pipe to the injection circuit or the bypass circuit, a solenoid valve provided in the injection circuit, and a first temperature sensor that is provided on the heat source side heat exchanger side and detects an outdoor temperature When provided in the utilization-side heat exchanger side, a second temperature sensor for detecting the room temperature, the detection signal from the first and second temperature sensors Uptake, larger than the temperature difference is judged value between the outdoor temperature and the indoor temperature, and when the temperature difference between the set temperature and the indoor temperature is greater than the determination value, the compression chamber side of the compressor in the injection circuit A signal for communicating the pipe to the injection circuit is output to the three-way valve and an open signal is output to the electromagnetic valve, and the temperature difference between the outdoor temperature and the room temperature is smaller than the judgment value, and the set temperature and the room temperature And a signal for closing the communication between the piping on the compression chamber side of the compressor and the injection circuit in the injection circuit is output to the three-way valve and the electromagnetic valve. it is obtained by a controller you force out of the close signal.
[0012]
Furthermore, in the above, the compressor is a variable capacity compressor whose operating frequency is controlled from the minimum frequency to the maximum frequency, and when the operating frequency becomes the minimum frequency, the bypass circuit is opened and injection is not performed. Is desirable.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 and 2 show a system configuration of a heat pump cycle of an air conditioner, which includes a compressor 1, a four-way valve 2, a heat source side heat exchanger (outdoor heat exchanger) 3, a first pressure reducing device 4, a receiver 5, and a check valve. 6, the 2nd decompression device 7a, the utilization side heat exchanger (indoor heat exchanger) 8a, the blocking valve 9, and the compressor 1 are connected by piping in order. Furthermore, it has an injection circuit (a circuit connecting the pipe 111, the pipe 112, and the pipe 109) that connects the receiver 5 and the compression chamber in the compression process of the compressor 1, and a bypass that connects the injection circuit and the suction side pipe 108 of the compressor 1 It has a circuit (pipe 110).
[0014]
A three-way valve 10 which is a flow path switching valve is provided at a connection point between the injection circuit and the bypass circuit, and switches between the bypass circuit and the injection circuit. Further, the bypass circuit (pipe 110) is provided with a capillary tube 12 as a pressure reducing device, and adjusts the flow rate of the refrigerant flowing through the bypass circuit. Instead of the capillary tube 12, a flow rate adjusting valve or an electronic expansion valve may be used.
[0015]
Furthermore, an electromagnetic valve 11 is provided in the injection circuit (pipe 111, pipe 112) between the three-way valve 10 and the receiver 5, so that the injection circuit can be opened and closed. The receiver adjusts the necessary refrigerant amount difference between the cooling operation and the heating operation, and the necessary refrigerant amount difference between the rated capacity operation (high load operation) and the intermediate capacity operation (low load operation).
[0016]
1 and 2 show the refrigerant flow during the cooling operation. The refrigerant that has become high-temperature and high-pressure gas in the compressor 1 is directed to the heat source side heat exchanger (outdoor heat exchanger) 3 by the four-way valve 2. In the heat source side heat exchanger 3, heat is radiated to the blown air (the blower system is not shown), and the refrigerant condenses into a gas-liquid two-phase, saturated liquid or supercooled liquid refrigerant state. The determination of the state is controlled by the throttle amount of the first pressure reducing device 4. The refrigerant that has passed through the first decompression device 4 is decompressed and enters a gas-liquid two-phase state and flows into the receiver 5. A saturated liquid refrigerant or a gas-liquid two-phase refrigerant is taken out from the receiver 5, and then passes through the blocking valve 6 to reach the second pressure reducing device 7a. The second pressure reducing device 7a becomes a gas-liquid two-phase refrigerant having a temperature lower than the room air, and flows into the use side heat exchanger (indoor heat exchanger) 8a. In the use-side heat exchanger 6a, heat is absorbed from the blown room air (the blower system is not shown), and becomes a gas refrigerant and returns to the compressor 1. The refrigerant flow during the heating operation is reversed by switching the four-way valve 2.
[0017]
FIG. 1 shows the refrigerant flow in the injection circuit, and FIG. 2 shows the refrigerant flow in the bypass circuit. As shown in FIG. 1, when the three-way valve 10 is switched to the injection circuit side and the electromagnetic valve 11 on the injection circuit is open, the refrigerant is injected into the compression chamber in the compression process of the compressor 1. At this time, the bypass circuit is closed. When the electromagnetic valve 12 is closed, the injection circuit is closed even if the three-way valve 10 is switched to the injection circuit side.
[0018]
There are two types of injection methods depending on the state of the refrigerant taken out from the receiver 5. When the liquid or gas-liquid two-phase refrigerant is taken out and injected into the compressor 1, it becomes liquid injection, and the saturated gas refrigerant is taken out from the compressor. When it is injected into 1, gas injection is performed.
[0019]
Hereinafter, it demonstrates as what performs gas injection. The driving force of gas injection is a pressure difference between the pressure of the compression chamber into which the compressor 1 is injected and the pressure of the receiver 5. Therefore, gas injection is performed when the pressure of the receiver 5 is higher than the pressure in the compression chamber of the compressor 1. As shown in FIG. 2, when the three-way valve 10 is switched to the bypass circuit, the compression chamber in the compression process of the compressor 1 and the suction side pipe 108 of the compressor 1 are connected, and the compression chamber of the compressor 1 is connected. Since the pressure is lower than the pressure in the suction side pipe 108 of the compressor 1, the refrigerant flows out (bypass) from the compression chamber in the compression process of the compressor 1 to the suction side pipe 108 of the compressor 1. At this time, the injection circuit is closed.
[0020]
The above air conditioner can select three operation methods for each of the cooling operation and the heating operation. 3 to 5, each operation will be described using a Mollier diagram. The horizontal axis of the Mollier diagram is enthalpy h, and the vertical axis is pressure p. Line 81 is a saturated liquid line, and line 82 is a saturated gas line. The operation is shown as during cooling operation.
[0021]
FIG. 3 shows a case where both the injection circuit and the bypass circuit are closed. In the figure, points P1 to P2 are the compressor 1, P2 to P3 are the heat source side heat exchanger (outdoor heat exchanger) 3, P3 to P4 are the first pressure reducing device 4 to the second pressure reducing device 7a, P4 to P1 has shown the state of the refrigerant | coolant in the utilization side heat exchanger (indoor heat exchanger) 8a. At this time, the mass flow rate G1 of the refrigerant is constant in the cycle.
[0022]
FIG. 4 shows the case where the injection circuit is open and the bypass circuit is closed.
Points P1 to P5 in the figure are the compression process (stage 1) of the compressor 1 until gas injection, and the refrigerant of the saturated gas P11 is gas-injected into the compression chamber, so that the refrigerant state P6 becomes P5 and the stage The second compression process P6 to P7 starts. P7 to P3 are the heat source side heat exchanger (outdoor heat exchanger) 3, P3 to P8 are the first pressure reducing device 4, and P8 is the receiver 5, and the saturated gas refrigerant of P11 and the saturated liquid refrigerant of P9 are in the receiver. Coexist. In the main cycle, the refrigerant of the P9 saturated liquid is taken out from the receiver 5 and sent to the second decompression device. P9 to P10 show the state of the refrigerant in the second decompression device 7a, and P10 to P1 show the usage-side heat exchanger 8a. The mass flow rate of the refrigerant in the cycle is G2 = G3 + G4 where G2 is the heat source side heat exchanger, G3 is the injection circuit, and G4 is the use side heat exchanger. Naturally, in the compression process of the compressor 1, the flow rate of the refrigerant in the compression chamber before and after the injection is different from that of G4 and G2, respectively. Actually, since the gas injection is performed by a pressure difference between the receiver 5 and the compression chamber of the compressor 1, it is not performed instantaneously as in P6, but is performed sequentially over a certain time.
[0023]
FIG. 5 shows a case where the injection circuit is closed and the gas bypass circuit is open. Since P1 to P2 are the compressor 1, and the compression chamber having the pressure of P5 is connected to the suction side piping of the compressor 1, the refrigerant flows out from the compression chamber to the suction side piping of the compressor 1. P2 to P3 are the heat source side heat exchanger 3, P3 to P4 are the first expansion valve to the second expansion valve, and P4 to P12 are the use side heat exchanger 8a (indoor heat exchanger). Therefore, if the mass flow rate of the refrigerant at the time of suction of the compressor 1 is G7 and the bypass flow rate is G6, the refrigerant amount flowing in the cycle is G5 = G7−G5.
[0024]
The coefficient of performance of the cycles of FIGS. 4 and 5 (for example, during cooling operation: cooling COP = cooling capacity / power consumption) is compared with FIG. 3 as a reference. The cooling capacity is the product of the enthalpy difference of the use side heat exchanger (indoor heat exchanger (evaporator)) and the refrigerant mass flow rate. When gas injection is performed, the enthalpy difference in the use-side heat exchanger is Δh (FIG. 4) = h (P1) −h (P10) in FIG. On the other hand, the enthalpy difference in FIG. 3 is Δh (FIG. 3) = h (P1) −h (P4). Since the enthalpies of P1 and P3 are the same, Δh (FIG. 4)> Δh (FIG. 3), and if the capacity is the same, the refrigerant flow rate may be smaller when the gas injection is performed (G4 <G1). Therefore, the compression work between P1 and P5 of the compressor 1 decreases, that is, the denominator of the coefficient of performance decreases and the coefficient of performance increases.
[0025]
In the case of bypass (FIG. 5), the enthalpy difference of the use side heat exchanger is not changed, but the mass flow rate of the refrigerant is reduced (G5 = G7−G6: G7 = G1 if the theoretical stroke volume of the compressor 1 is the same). ), Ability can be reduced. Further, since the flow rate in the section from P5 to P2 of the compressor 1 is reduced, the compression work is reduced by this amount, and the power consumption is also reduced. For example, in the case of a compressor that performs capacity control with an inverter, the operation frequency of the compressor is changed according to the load. Will be. At this time, if a bypass circuit is used, the capacity can be adjusted according to the load, and operation can be performed with a high coefficient of performance. In addition, if a constant speed compressor is used, capacity control by the compressor operation method is not possible, but if the bypass circuit is used, capacity control is possible and operation at an operating point with high compressor efficiency is possible. Become.
[0026]
Furthermore, regardless of the inverter-driven compressor or the constant speed compressor, the bypass circuit is opened and the refrigerant is returned to the compressor suction side, so that it flows through the heat source side heat exchanger (outdoor heat exchanger) during cooling operation. The refrigerant mass flow rate is reduced, which is equivalent to an increase in the apparent heat exchanger, the condensation pressure is reduced, and the compressor discharge pressure (Pd) is reduced. Even in the use side heat exchanger (indoor heat exchanger), the refrigerant mass flow rate is reduced, so that the pressure loss is reduced, the evaporation pressure is increased, and the suction pressure (Ps) of the compressor can be increased. As a result, the pressure ratio (Pd / Ps) is reduced, the compression work can be reduced, and the air conditioner is energy-saving.
[0027]
In the above cycle, since three operation methods can be selected for both cooling and heating operation, the gas injection circuit has a large pressure ratio (= Pd / Ps) between the compressor suction pressure (Ps) and the compressor discharge pressure (Pd). In this case, the bypass circuit is used when the pressure ratio is small. For example, when applied to indoor and outdoor temperature conditions according to JIS standards, the gas injection circuit is used under overload conditions and rated conditions, and the bypass circuit is used under intermediate conditions. Normally, the optimum three driving methods are selected based on information set and stored in advance according to each driving condition.
[0028]
Specifically, an outdoor intake air temperature, an indoor intake air temperature, a set temperature set by a user and an operating frequency of the compressor are detected, and set values (for example, programs and tables) in which the data is stored in advance in a memory. Select driving according to. FIG. 1 also shows the configuration of the control system. A temperature sensor is provided on the suction side of the heat source side heat exchanger (outdoor heat exchanger) 3 to measure the outdoor temperature, and the use side heat exchanger (indoor heat exchanger) 8a A temperature sensor is provided on the suction side to measure the room temperature. A thermistor or a thermocouple is used for the temperature sensor.
[0029]
As an input device, for example, a user inputs a set temperature from a remote controller 70. In the case of inverter control, the compressor is provided with a measurement sensor for operating frequency, and the operating frequency is obtained from the current waveform or voltage waveform. Or you may substitute with the setting frequency of an inverter. The sensor and the input device (remote control) are connected to the controller 61, and this information is input to the controller 61. For example, information is transmitted to the controller 61 of the outdoor unit 21 via the indoor unit 22a.
[0030]
A flow path switching valve (three-way valve) 10 that switches between an injection circuit and a bypass circuit and an on-off valve (electromagnetic valve) 11 that opens and closes the injection circuit are also connected to the controller 61. The controller 61 receives data from the sensor and the input device, selects an optimum driving method from the three driving methods based on the judgment value stored in advance, and the controller 61 sends a control signal to the three-way valve 10 or the like. Control is transmitted to the electromagnetic valve 11. For example, when the temperature difference between the outdoor temperature and the room temperature is larger than the determination value and the temperature difference between the set temperature and the room temperature is larger than the determination value, the injection circuit is opened. If the temperature difference between the outdoor temperature and the room temperature is smaller than the determination value and the temperature difference between the set temperature and the room temperature is smaller than the determination value, the bypass circuit is opened. In other operating conditions, the operation is performed to close the bypass circuit and the injection circuit.
[0031]
FIG. 6 shows the structure of the scroll compressor used in this embodiment and the injection circuit connected to the compression chamber. In the case of a scroll compressor, two compression chambers are formed simultaneously. The compression chamber is formed by combining a wrap of the fixed scroll 42 and the orbiting scroll 43. Each compression chamber is provided with injection ports 47a and 47b at a predetermined pressure ratio. The ports 47a and 47b are most easily provided on the fixed scroll. The ports 47a and 47b are connected to the pipe 109 shown in FIG.
[0032]
7 and 8 show the cycle configuration of an air conditioner according to another embodiment, which is basically the same as the cycle configuration shown in FIGS. 1 and 2.
FIG. 7 shows a case where a four-way valve 13 is used instead of the three-way valve 10 shown in FIGS. 1 and 2, and one of the four passages of the four-way valve is always closed. The operation is basically the same when the three-way valve 10 is used and when the four-way valve 13 is used.
FIG. 8 shows a case where an electromagnetic valve 14 is used instead of the three-way valve 10 shown in FIGS. 1 and 2, and the electromagnetic valve 14 is connected between the capillary tube 13 on the pipe 110 and the connection point 19 between the injection circuit. Provided. When the solenoid valve 11 is opened and the solenoid valve 14 is closed, the injection circuit can be used, and when the solenoid valve 11 is closed and the solenoid valve 14 is opened, the bypass circuit can be used. When both are closed, the normal cycle configuration is obtained.
[0033]
FIG. 9 shows a cycle configuration according to another embodiment for performing gas injection, and the use of the gas injection circuit and the bypass circuit is the same as that of the air conditioner shown in FIGS. 1 and 2.
9 includes a compressor 1, a four-way valve 2, a heat source side heat exchanger 3, a receiver 5, a blocking valve 6, a second pressure reducing device 7a, a use side heat exchanger 8a, a blocking valve 9, and the compressor 1. A flow control circuit 16 is provided at the inlet of the receiver 5 so that the refrigerant inlets of the receiver 5 are in one direction both during cooling operation and during heating operation.
[0034]
The flow control circuit 16 constitutes a bridge circuit using four check valves 14a, 14b, 14c, 14d and a variable throttle electronic expansion valve as the first pressure reducing device 4. Further, an injection circuit for connecting the receiver 5 and the compressor 1 is provided. From the receiver 5 side, a pipe 116, a third pressure reducing device (injection pressure reducing device) 18, a pipe 117, a pipe 111, an on-off valve 11, a pipe 112, The pipe 109 is configured.
[0035]
An intermediate heat exchanger 17 is provided on the downstream side of the third decompression device 18 in order to exchange heat between the refrigerant on the downstream side of the third decompression device 18 and the refrigerant on the downstream side of the receiver 5. In the injection circuit, the receiver 5 The saturated liquid refrigerant is taken out of the refrigerant, and reduced to the injection pressure by the third pressure reducing device 18 to obtain a gas-liquid two-phase refrigerant. Thereafter, the intermediate heat exchanger 17 absorbs heat from the refrigerant downstream of the third decompression device 18 from the refrigerant downstream of the main receiver 5, and the gas-liquid two-phase refrigerant is completely gasified to intermediate compression of the compressor 1. Inject into the room. On the other hand, the mainstream refrigerant flow is a gas-liquid two-phase refrigerant state in which the saturated liquid refrigerant and the saturated gas refrigerant are taken out from the pipe 116 connected to the receiver 5, but are condensed by the intermediate heat exchanger 17 and further cooled. It becomes a liquid refrigerant in a cooled state and flows to the use side heat exchange 8a. When the connection pipe 105 and the pipe 106 that connect the outdoor unit 21 and the indoor unit 22a are long pipes (for example, 30 m or more), the gas injection method in FIG. 9 is more effective than that in FIG. The possible operating range is increased.
[0036]
As described above, the bypass circuit connecting the injection circuit and the suction side piping of the compressor is provided in the injection circuit, and the refrigerant is discharged from the compression chamber of the compressor by using the injection circuit by switching the circuit. Capable of capacity control. Basically, regardless of the presence or absence of inverter control, the gas injection circuit is effectively used to enable capacity control in the direction of reducing the capacity. As a result, capacity control that can further reduce the capacity is possible with inverter control models even at the lowest compressor operating frequency, and capacity control of capacity increase by gas injection (improves energy saving when capacity is constant) is possible. It is.
[0037]
Further, in an air conditioner equipped with an injection circuit, the circuit can be switched by adding one three-way valve, four-way valve or electromagnetic valve. Furthermore, the sensor used for operation control generally uses information from an existing temperature sensor or the like possessed by an air conditioner, and does not need to be newly installed. As a result, for example, when an inverter-driven compressor is used, the capacity can be further reduced even when the compressor operating frequency is minimized, and the capacity can be further reduced. By creating an optimum operating state, it is possible to operate with a high coefficient of performance of the air conditioner. In addition, if a constant speed compressor is used, extra work will be caused to the compressor in the case of maladjustment with the load, but by using the bypass circuit, capacity control becomes possible and the air conditioner Operation with a high coefficient of performance is possible. In addition, since it is equipped with an injection circuit, it is possible to reduce the operating frequency of the compressor if the same capacity is achieved if the gas injection is performed, as compared to the case where the gas injection is not performed. Power consumption is reduced and energy saving operation (high coefficient of performance) is achieved. In the constant speed compressor, if the same stroke volume is used, the capacity can be increased, and if the same capacity is used, the stroke volume can be reduced. Therefore, energy saving and downsizing of the compressor operation can be achieved.
[0038]
Regardless of inverter-driven compressors or constant speed compressors, the mass of refrigerant flowing through the heat source side heat exchanger (outdoor heat exchanger) during cooling operation by opening the bypass circuit and returning the refrigerant to the compressor suction side The flow rate is reduced, which is equivalent to the increase in the apparent heat exchanger, the condensing pressure is lowered, and the compressor discharge pressure (Pd) can be lowered. Even in the use side heat exchanger (indoor heat exchanger), the refrigerant mass flow rate is reduced, so that the pressure loss is reduced, the evaporation pressure is increased, and the suction pressure (Ps) of the compressor can be increased. Therefore, the pressure ratio (Pd / Ps) is reduced, and the compression work can be reduced.
[0039]
By combining the injection circuit and bypass circuit and selecting the operation method according to the conditions, the injection port can be used effectively, enabling operation with a high coefficient of performance in a wide operating range, and improving the operating efficiency of the air conditioner Energy saving.
[0040]
In addition, the effect was explained assuming that the compressor is driven by an inverter and the operating frequency of the compressor can be changed. However, in a compressor that operates at a constant speed, the stroke volume (theoretical discharge volume) of the compressor is reduced by gas injection. Accordingly, the load on the compressor is reduced accordingly, so that the electric input is reduced, and the required torque is reduced, so that the motor capacity can be reduced. Furthermore, the effect that the casing of a compressor etc. can be made small is also acquired.
[0041]
Furthermore, by providing a bypass circuit using a gas injection circuit, stepwise capacity control is possible even in a compressor that operates at a constant speed. In addition, the injection method can be liquid injection instead of gas injection, but the effect differs depending on the port position.
[0042]
Furthermore, although the compressor has been described as a scroll compressor, the same applies to a rotary compressor. Furthermore, R22, R410A, R32, R407C, natural refrigerants such as carbon dioxide gas and HC refrigerant can be used as the refrigerant.
[0043]
【The invention's effect】
As described above, according to the present invention, since the bypass circuit connecting the injection circuit and the suction side piping of the compressor is provided in the injection circuit, the injection circuit is diverted to allow the refrigerant to flow out from the compressor chamber. By enabling the capacity control and opening the bypass circuit and returning the refrigerant to the compressor suction side, the pressure ratio (Pd / Ps), which is the ratio between the compressor suction pressure and the compressor discharge pressure, can be reduced.
[0044]
Therefore, an optimum operating state adapted to the load can be created, an operation with a high coefficient of performance is possible in a wide operating range, the operating efficiency of the air conditioner can be improved, and energy saving can be achieved.
[Brief description of the drawings]
FIG. 1 is a system configuration diagram of an air conditioner according to an embodiment (opening of a gas injection circuit).
FIG. 2 is a system configuration diagram showing a state where a bypass circuit is opened in FIG. 1;
FIG. 3 is a Mollier diagram of cycle operation when neither gas injection nor bypass of an air conditioner according to an embodiment is performed.
FIG. 4 is a Mollier diagram at the time of gas injection of the air conditioner according to the embodiment.
FIG. 5 is a Mollier diagram at the time of bypass of the air conditioner according to the embodiment.
FIG. 6 is a cross-sectional view of a compressor according to an embodiment.
FIG. 7 is a system configuration diagram of an air conditioner according to another embodiment.
FIG. 8 is a system configuration diagram of an air conditioner according to another embodiment.
FIG. 9 is another system configuration diagram of the air conditioner according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Four-way valve, 3 ... Heat source side heat exchanger (outdoor heat exchanger), 4 ... First decompression device, 5 ... Receiver, 6 ... Stop valve, 7a, 7b ... Second decompression device, 8a 8b ... use side heat exchanger (indoor heat exchanger), 9 ... blocking valve, 10 ... three-way valve, 11 ... solenoid valve, 12 ... capillary tube, 13 ... four-way valve, 14 ... solenoid valve, 44 ... suction port 45a, 45b ... compression chamber, 46 ... discharge port, 47a, 47b ... injection port, 110 ... bypass piping, 111, 112 ... injection piping.

Claims (2)

In an air conditioner configured by connecting a compressor, a heat source side heat exchanger, a first pressure reducing device, a receiver, a second pressure reducing device, and a use side heat exchanger in a sequential pipe to constitute a refrigeration cycle,
An injection circuit connecting the receiver and the compression chamber of the compressor;
A bypass circuit connecting the injection circuit and a suction side pipe of the compressor;
A three-way valve that switches a pipe on the compression chamber side of the compressor in the injection circuit to the injection circuit or the bypass circuit;
A solenoid valve provided in the injection circuit;
A first temperature sensor provided on the heat source side heat exchanger side for detecting an outdoor temperature;
A second temperature sensor provided on the use side heat exchanger side for detecting an indoor temperature;
When detection signals from the first and second temperature sensors are taken in, the temperature difference between the outdoor temperature and the room temperature is larger than the determination value, and the temperature difference between the set temperature and the room temperature is also larger than the determination value A signal for communicating the compressor-side piping of the compressor in the injection circuit to the injection circuit is output to the three-way valve and an open signal is output to the electromagnetic valve, and the temperature difference between the outdoor temperature and the indoor temperature Is a signal that closes the communication between the piping on the compression chamber side of the compressor and the injection circuit in the injection circuit when the difference between the set temperature and the room temperature is also smaller than the determination value. the air conditioner is characterized in that a controller you outputs a close signal to the solenoid valve to output to the three-way valve.   2. The compressor according to claim 1, wherein the compressor is a variable capacity compressor in which an operation frequency is controlled from a minimum frequency to a maximum frequency, and when the operation frequency becomes the minimum frequency, the bypass circuit is opened. An air conditioner characterized by not performing injection.

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