JP2012167869A - Air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve further improvement in efficiency, which is necessary to satisfy a demand for energy saving in an air conditioner.SOLUTION: The air conditioner constitutes a heat pump type refrigeration cycle configured by connecting a compressor 5, a four-way valve 6, an indoor heat exchanger 3, a pressure reducer 9 and an outdoor heat exchanger 7. The air conditioner includes: a first bypass circuit 10, which has a first two-way valve 11 and a refrigerant heater 13, and which connects a route between the indoor heat exchanger 3 and the pressure reducer 9 with a suction side of the compressor 5; and a second two-way valve 15. Further, the air conditioner includes: a second bypass circuit 14 for connecting a route between the pressure reducer 9 and the outdoor heat exchanger 7 with a discharge side of the compressor 5; and a third bypass circuit 18 including a flow regulation valve 19 and connecting a route between the pressure reducer 9 and the outdoor heat exchanger 7 to a route between the first two-way valve 11 and the refrigerant heater 13. By bypassing a portion of the refrigerant to the third bypass circuit 18 during a heating operation, pressure loss of the outdoor heat exchanger 7 can be reduced, which increases heating efficiency.

Description

  The present invention relates to an air conditioner that mainly performs indoor cooling and heating.

  A heat pump refrigeration cycle for performing conventional hot bypass defrosting will be described with reference to FIG.

  FIG. 11 is a configuration diagram showing a refrigeration cycle of a conventional air conditioner.

  As shown in FIG. 11, a first bypass circuit 105 is provided to connect between the indoor heat exchanger 101 and the decompressor 102, and the four-way valve 103 and the suction side of the compressor 104. An energy charging system provided with a first two-way valve 106 and a refrigerant heater 107 has been proposed (for example, Patent Document 1).

JP 2009-47344 A

  The air conditioner is required to save energy, and further efficiency improvement is an issue. The present invention solves such a conventional problem, and an air conditioner that can improve heating efficiency by effectively using the amount of heat of a refrigerant heater in a heating operation other than the defrosting step. I will provide a.

  In order to solve the above problems, an air conditioner according to the present invention includes a heat pump refrigeration cycle in which a compressor, a decompressor, an outdoor heat exchanger, and an indoor heat exchanger are connected by a refrigerant circuit, and a heat pump refrigeration cycle during cooling operation. In the first direction in which the refrigerant discharged from the compressor passes through the outdoor heat exchanger, the decompressor, and the indoor heat exchanger and returns to the compressor in this order, the refrigerant discharged from the compressor is discharged from the compressor during heating operation. Switching means for switching between the second direction in which the refrigerant passes through the indoor heat exchanger, the decompressor, and the outdoor heat exchanger in this order and returns to the compressor, a first two-way valve, and a refrigerant heater. Furthermore, it has the 1st bypass circuit which connects the one end between an indoor heat exchanger and a pressure reduction device, and the suction side of a compressor, and a 2nd two-way valve, between a pressure reduction device and an outdoor heat exchanger A second bypass circuit that connects one end and the discharge side of the compressor, a first connection portion provided between the switching means that connects the decompressor to the outdoor heat exchanger, and the compressor suction from the first connection portion It has a 3rd bypass circuit which connects with the 2nd connection part provided between the sides, and heats the refrigerant which flows through the 3rd bypass circuit with a refrigerant heater.

  According to the present invention, since power consumption can be reduced by improving heating efficiency, energy saving can be achieved.

It is a block diagram which shows the refrigerating cycle of the air conditioner which concerns on Embodiment 1 of this invention. It is a block diagram which shows an example of the switching means in the refrigerating cycle of the air conditioner which concerns on Embodiment 1 of this invention. It is a matrix figure which shows the relationship between the driving | running state and valve operation in the refrigerating cycle of the air conditioner which concerns on Embodiment 1 of this invention. It is a flowchart which shows the opening degree control method of the flow regulating valve in the refrigerating cycle of the air conditioner which concerns on Embodiment 1 of this invention. It is a flowchart which shows switching control from the heating operation to the defrost operation in the refrigerating cycle of the air conditioner according to Embodiment 1 of the present invention. It is a graph which shows the relationship between the calorie | heat amount of the refrigerant | coolant heater in a refrigerating cycle of the air conditioner which concerns on Embodiment 1 of this invention, and a heating efficiency (COP) improvement rate. It is a block diagram which shows the refrigerating cycle of the air conditioner which concerns on Embodiment 2 of this invention. It is a block diagram which shows the refrigerating cycle of the air conditioner which concerns on Embodiment 3 of this invention. It is a matrix figure which shows the relationship between the driving | running state and valve operation in the refrigerating cycle of the air conditioner concerning Embodiment 3 of this invention. It is a block diagram which shows another example of the refrigerating cycle of the air conditioner in the refrigerating cycle of the air conditioner which concerns on Embodiment 3 of this invention. It is a block diagram which shows the refrigerating cycle of the conventional air conditioner.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a configuration diagram showing a refrigeration cycle of an air conditioner according to Embodiment 1 of the present invention.

  As shown in FIG. 1, the air conditioner connects an indoor unit 1 and an outdoor unit 2. The indoor unit 1 includes an indoor heat exchanger 3 and an indoor fan 4 that heats the indoor heat exchanger 3 by applying indoor air to the indoor heat exchanger 3. On the other hand, the outdoor unit 2 includes a compressor 5 that compresses refrigerant, a four-way valve 6 as switching means that switches the direction of the refrigerant compressed by the compressor 5 between heating operation and cooling operation, and an outdoor unit that is connected to the four-way valve 6. A heat exchanger 7, an outdoor fan 8 that exchanges heat by applying outside air to the outdoor heat exchanger 7, and a decompressor 9 provided between the outdoor heat exchanger 7 and the indoor heat exchanger 3 are provided.

  Further, the outdoor unit 2 branches from between the decompressor 9 and the indoor heat exchanger 3 and is connected to the compressor 5 suction, and a first bypass circuit 10 that controls opening and closing of the first bypass circuit 10. A refrigerant that includes a two-way valve 11 and heat storage means 12 (brine as an example) that stores heat using exhaust heat of the compressor 5, and that heats the refrigerant flowing through the first bypass circuit 10 by the amount of heat stored in the heat storage means 12. The heater 13, the second bypass circuit 14 branched from between the indoor heat exchanger 3 and the compressor 5 and connected between the decompressor 9 and the outdoor heat exchanger 7, and opening / closing of the second bypass circuit 14 A second two-way valve 15 is provided.

  The intake of the compressor 5 is provided with an accumulator 16 to prevent liquid return to the compressor 5 by temporarily storing liquid refrigerant. Here, although the four-way valve 6 is applied as the switching means, the switching means of the present invention is not limited to this.

  FIG. 2 is a configuration diagram showing an example of switching means in the refrigeration cycle of the air conditioner according to Embodiment 1 of the present invention. For example, the switching means may be a circuit in which two three-way valves 17 are connected in a loop by a pair of pipes as shown in FIG. Alternatively, the switching means may be a so-called bridge circuit as shown in FIG. The heat source of the refrigerant heater 13 is not particularly limited to the heat storage means 12, and a heater may be used as another example, or natural energy such as solar heat may be used from the viewpoint of environmental consideration.

  The outdoor unit 2 further includes a first connection A provided between the switching means (here, the four-way valve 6) connected from the decompressor 9 to the outdoor heat exchanger 7, and the suction of the compressor 5 from the first connection A. A third bypass circuit that directly connects the second connecting portion B provided between the two sides.

  That is, in the first embodiment of the present invention, the outdoor unit 2 further branches from the decompressor 9 to the outdoor heat exchanger 7 and is connected between the first two-way valve 11 and the refrigerant heater 13. 3 bypass circuit 18 and a flow rate adjusting valve 19 for adjusting the flow rate of the refrigerant flowing through the third bypass circuit 18.

  As an example of the flow rate adjustment valve 19, an expansion valve that can be fully closed and that can adjust the opening degree from 0 to 480 pls from the fully closed state to the fully open state can be used. The outdoor unit 2 further includes heating load detection means 20 that detects the size of the heating load during the heating operation. As an example of the heating load detection means 20, when the heating load is large, the refrigerant flow rate is large, so the pressure loss of the outdoor heat exchanger 7 increases, the pressure difference before and after the flow rate adjustment valve 19 increases, and conversely the heating load Is small, the flow rate of the refrigerant is reduced, so that the pressure loss of the outdoor heat exchanger 7 is reduced and the pressure difference before and after the flow rate adjustment valve 19 is also reduced. Therefore, the differential pressure before and after the flow rate adjustment valve 19 is detected. A differential pressure detection means 21 (a differential pressure gauge as an example) can be applied (FIG. 1 shows a differential pressure detection means 21 as an example of the heating load detection means 20). Further, the heating load detection means 20 is not limited to the differential pressure detection means 21. As another example, the number of rotations of the compressor 5 and the input to the compressor 5 increase and decrease as the heating load increases and decreases. A method of detecting the number of revolutions of 5 or the input to the compressor 5 may be used.

  Further, in the outdoor unit 2, it is confirmed that frost is generated in the outdoor heat detection means 22 for detecting the outdoor air temperature, the outdoor heat exchange temperature detection means 23 for detecting the outdoor heat exchange temperature, and the outdoor heat exchanger 7. Frost generation detecting means 24 for detecting, refrigerant heater temperature detecting means 25 for detecting the temperature of the refrigerant heater 13, and flow temperature adjusting valve pre-temperature detecting means for detecting the pipe temperature between the pressure reducer and the flow rate adjusting valve 19. 26 and a refrigerant heater outlet temperature detecting means 27 for detecting the pipe temperature at the outlet of the refrigerant heater 13.

  The outdoor unit 2 further receives control information from each detection means and controls the control means 28 (not shown) for controlling the opening / closing of the first two-way valve 11 and the second two-way valve 15 and the opening degree of the flow rate adjusting valve 19. ) And time measuring means 29 (not shown) capable of measuring time. For example, a thermistor can be used as an example of the temperature detecting means. As an example of the detection method of the frost formation detection means 24, when the outdoor heat exchanger 7 temperature is 0 ° C. or lower and the outdoor heat exchanger 7 temperature is 9 ° C. or lower than the outdoor air temperature, it is detected that frost is generated. be able to. As an example of the control means 28, a control board on which a microcomputer is mounted can be used, and as an example of the time measurement means 29, a timer can be used.

  Next, the operating state and the respective valve operations will be described.

  FIG. 3 is a matrix diagram showing the relationship between the operating state and the valve operation in the refrigeration cycle of the air conditioner according to Embodiment 1 of the present invention.

  As shown in FIG. 3, during the cooling operation, the first two-way valve 11 and the second two-way valve 15 are closed, and the flow rate adjustment valve 19 is also closed. By such valve operation, the high-temperature refrigerant discharged from the compressor 5 flows into the outdoor heat exchanger 7 via the four-way valve 6 switched to the cooling operation state, and is condensed and liquefied by exchanging heat with the outside air. The liquefied refrigerant is depressurized by the decompressor 9 to become a low temperature, and after evaporating and evaporating by exchanging heat with indoor air in the indoor heat exchanger 3, the refrigerant is sucked into the compressor 5 via the four-way valve 6. At this time, since the first two-way valve 11, the second two-way valve 15, and the flow rate adjustment valve 19 are closed, the refrigerant does not flow to each bypass circuit.

  Next, a defrosting operation in the case where frost formation has occurred in the outdoor heat exchanger 7 when the outside air temperature is particularly low during the heating operation will be described.

  As shown in FIG. 3, during the defrosting operation, the first two-way valve 11 and the second two-way valve 15 are opened, and the flow rate adjustment valve 19 is closed. By this valve operation, a part of the high-temperature refrigerant discharged from the compressor 5 flows into the indoor heat exchanger 3 via the four-way valve 6 switched to the heating operation state, and exchanges heat with indoor air to be condensed and liquefied. . The liquefied refrigerant flows into the first bypass circuit 10, is heated by the refrigerant heater 13, evaporates and is evaporated and sucked into the compressor 5, and the remaining high-temperature refrigerant discharged from the compressor 5. Flows into the second bypass circuit 14, defrosts by exchanging heat in the outdoor heat exchanger 7, and simultaneously performs a second bypass operation that is sucked into the compressor 5 via the four-way valve 6, thereby heating The outdoor heat exchanger 7 can be defrosted while operating. At this time, since the flow rate adjusting valve 19 is closed, the refrigerant does not flow into the third bypass circuit 18.

  Next, the heating operation will be described.

  As shown in FIG. 3, during the heating operation, the first two-way valve 11 and the second two-way valve 15 are closed, and the flow rate adjustment valve 19 is opened to adjust the opening degree. By such valve operation, the high-temperature refrigerant discharged from the compressor 5 flows into the indoor heat exchanger 3 via the four-way valve 6 switched to the heating operation state, and exchanges heat with indoor air to be condensed and liquefied. After the liquefied refrigerant is decompressed by the decompressor 9 and becomes low temperature, a part of the refrigerant flows to the third bypass circuit 18 by the flow rate adjusting valve 19 and is heated by the refrigerant heater 13 to be evaporated and evaporated. 5 and the remaining refrigerant that has not flowed to the third bypass circuit 18 flow to the outdoor heat exchanger 7, exchange heat with the outside air, evaporate and evaporate, and then the compressor passes through the four-way valve 6. 5 inhaled. At this time, since the first two-way valve 11 and the second two-way valve 15 are closed, the refrigerant does not flow through the first and second bypass circuits 14.

  By flowing a part of the refrigerant to the third bypass circuit 18 during the heating operation, the amount of refrigerant flowing to the outdoor heat exchanger 7 can be reduced and the pressure loss can be reduced, and the suction pressure of the compressor 5 is increased. be able to. Thereby, the input of the compressor 5 can be reduced, heating efficiency can be improved, and energy can be saved.

  In Embodiment 1 of the present invention, since the exhaust heat of the compressor 5 is stored and used as the heat source of the refrigerant heater 13 by the heat storage means 12, the refrigerant flows through the third bypass circuit 18 during the heating operation. If the heat quantity of the heat storage means 12 is deprived, there is a concern that the heat quantity of the heat storage means 12 is insufficient in the first bypass operation in which the refrigerant flows through the first bypass circuit 10 when switching to the defrosting operation. Therefore, since the differential pressure detection means 21 as the heating load detection means 20 has a high possibility of switching to the defrosting operation when the heating load is large, the refrigerant is supplied to the third bypass circuit 18 by closing the flow rate adjustment valve 19. So that the heat storage means 12 is not deprived of heat and the possibility of switching to the defrosting operation is low when the heating load is small. Therefore, the refrigerant is supplied to the third bypass circuit 18 by opening the flow control valve 19. It is effective to control the flow. Here, the threshold value of the heating load by the differential pressure detecting means 21 is determined by confirming the differential pressure before and after the flow regulating valve 19 under a heating low temperature condition in which the heating load is large and defrosting is necessary. Alternatively, the differential pressure immediately before switching to the defrosting operation in the actual use environment may be stored in the control means 28, and the differential pressure may be set as a threshold value.

  Next, the opening degree control of the flow rate adjustment valve 19 during the heating operation will be described with reference to FIG.

  FIG. 4 is a flowchart showing an opening control method of the flow rate adjustment valve in the refrigeration cycle of the air conditioner according to Embodiment 1 of the present invention.

  As shown in FIG. 4, after the heating operation is started (S0), for example, when the heating load measured by the differential pressure detecting means 21 is equal to or less than a predetermined value (S1), before the refrigerant heater 13 temperature and the flow rate adjustment valve 19 The temperature of the temperature is compared (S2), and when the refrigerant heater 13 temperature is higher than the temperature before the flow rate adjustment valve 19, that is, when the refrigerant before the flow rate adjustment valve 19 can be heated, the process proceeds to the next step (S3), When it is low, the opening degree of the flow regulating valve 19 is lowered (S4). Next, the temperature before the flow rate adjusting valve 19 and the temperature of the refrigerant heater 13 outlet temperature are compared (S3). When the refrigerant heater 13 outlet temperature is high, that is, when the refrigerant evaporates at the refrigerant heater 13 outlet. The opening degree of the flow rate adjusting valve 19 is increased (S5), and if lower, the opening degree of the flow rate adjusting valve 19 is decreased (S4). Next, a fixed detection interval time (10 seconds as an example) is measured by the time measuring means 29 (S6), and the flow returns to the temperature comparison (S2) flow again.

  In addition, after heating operation start (S0), when the heating load measured, for example with the differential pressure | voltage detection means 21 is larger than a predetermined value (S1), the opening degree of a flow regulating valve is lowered | hung (S4).

  Here, considering the detection variation of the temperature detecting means, such a temperature comparison is judged when a difference of 3 ° C. or more is detected, and when it is within 3 ° C., the opening degree of the flow regulating valve 19 is changed. It is better not to.

  In addition, the opening adjustment of the flow rate adjusting valve 19 is desirably changed by 1 pls in order to finely adjust the opening.

  Next, switching control from the heating operation to the defrosting operation will be described with reference to FIG.

  FIG. 5 is a flowchart showing switching control from the heating operation to the defrosting operation in the refrigeration cycle of the air conditioner according to Embodiment 1 of the present invention.

  As shown in FIG. 5, after the heating operation is started (S <b> 11), the frost formation detection means 24 detects whether frost is generated in the outdoor heat exchanger 7, and determines whether frost is generated or not. When the occurrence determination (S12) is performed and it is determined that frost formation has not occurred, a predetermined time (5 minutes as an example) until the next frost detection is detected by the time measurement means 29 as the detection interval time (S14). It waits and returns to frost formation determination (S12) again. If it is determined that frost formation has occurred, the first two-way valve 11 and the second two-way valve 15 are opened, the flow rate adjustment valve 19 is closed, and the defrosting operation is started (S13). After a predetermined time (as an example, 5 minutes) has elapsed (S15) in the time measuring means 29, the first two-way valve 11 and the second two-way valve 15 are closed again, and the flow rate adjustment valve 19 is opened to perform the defrosting operation. The process is finished (S16), and the time measurement means 29 controls the detection interval time until the next frost detection (S14) and then returns to the frost generation determination (S12).

  With the above configuration, during the heating operation, a part of the refrigerant is bypassed to the third bypass circuit 18, thereby reducing the amount of refrigerant flowing into the outdoor heat exchanger 7 and reducing pressure loss, thereby compressing the refrigerant. Heating efficiency can be improved by increasing the suction pressure of the machine 5. The refrigerant flow rate that can be passed through the third bypass circuit 18 is determined by the amount of heat necessary to evaporate the refrigerant in the refrigerant heater 13.

  FIG. 6 is a graph showing the relationship between the amount of heat of the refrigerant heater and the heating efficiency (COP) improvement rate in the refrigeration cycle of the air-conditioning apparatus according to Embodiment 1 of the present invention.

  As shown in FIG. 6, every time the amount of heat of the refrigerant heater 13 increases by 100 W, there is an effect of improving the heating efficiency by 0.5%.

(Embodiment 2)
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 7 is a configuration diagram showing a refrigeration cycle of an air conditioner according to Embodiment 2 of the present invention.

  As shown in FIG. 7, a heat pump refrigeration cycle in which a compressor 5, a four-way valve 6, an indoor heat exchanger 3, a first decompressor 30, a second decompressor 31, and an outdoor heat exchanger 7 are connected is configured. The gas-injection path 34 includes a gas-liquid separator 33 between the first decompressor 30 and the second decompressor 31 and injects only the gas refrigerant separated by the gas-liquid separator 33 into the suction of the compressor 5. It has. A first bypass circuit 10 that branches from between the indoor heat exchanger 3 and the first pressure reducer 30 and is connected to the suction of the compressor 5, and a first two that controls opening and closing of the first bypass circuit 10 The valve 11, the refrigerant heater 13 having the heat storage means 12 for heating the refrigerant in the first bypass circuit 10, and the second decompressor 31 and the outdoor heat are branched from between the indoor heat exchanger 3 and the compressor 5. A second bypass circuit 14 connected between the exchangers 7 and a second two-way valve 15 for controlling opening and closing of the second bypass circuit 14 are provided.

  In the second embodiment of the present invention, the third bypass circuit 18 is further branched from between the gas-liquid separator and the second pressure reducer 31 and merged into the gas injection path 34 via the refrigerant heater 13, 3 is provided with a flow rate adjusting valve 19 for adjusting the flow rate of the refrigerant flowing through the bypass circuit 18. Further, as the heating load detection means 20 for detecting the magnitude of the heating load during the heating operation, a differential pressure detection means 21 for detecting the differential pressure before and after the flow rate adjustment valve 19 is provided.

  Next, the valve operation in each operation state is the same as that of the first embodiment of the present invention, and will be described with reference to FIG.

  As shown in FIG. 3, during the cooling operation, the first two-way valve 11 and the second two-way valve 15 are closed, and the flow rate adjustment valve 19 is also closed. By such valve operation, the high-temperature and high-pressure refrigerant discharged from the compressor 5 flows into the outdoor heat exchanger 7 via the four-way valve 6 switched to the cooling operation state, and exchanges heat with the outside air to be condensed and liquefied. The liquefied refrigerant is once decompressed to an intermediate pressure by the second decompressor 31 to be in a gas-liquid two-phase state, and is separated into a gas refrigerant and a liquid refrigerant by the gas-liquid separator. The gas refrigerant passes through the gas injection path 34 and is returned to the suction of the compressor 5, and the liquid refrigerant is further decompressed to a low pressure by the first decompressor. The depressurized refrigerant is evaporated with the indoor heat exchanger 3 through heat exchange with room air, and then passes through the four-way valve 6 to join with the gas refrigerant flowing from the gas injection path 34 and is sucked into the compressor 5. . At this time, since the first two-way valve 11, the second two-way valve 15, and the flow rate adjustment valve 19 are closed, the refrigerant does not flow to each bypass circuit.

  Next, a defrosting operation in the case where frost formation has occurred in the outdoor heat exchanger 7 when the outside air temperature is particularly low during the heating operation will be described.

  As shown in FIG. 3, during the defrosting operation, the first two-way valve 11 and the second two-way valve 15 are opened, and the flow rate adjustment valve 19 is closed. By this valve operation, a part of the high-temperature refrigerant discharged from the compressor 5 flows into the indoor heat exchanger 3 via the four-way valve 6 switched to the heating operation state, and exchanges heat with indoor air to be condensed and liquefied. . The liquefied refrigerant flows into the first bypass circuit 10, is heated by the refrigerant heater 13, vaporizes and evaporates and is sucked into the compressor 5, and the remaining high-temperature refrigerant discharged from the compressor 5. Flows into the second bypass circuit 14, defrosts by exchanging heat in the outdoor heat exchanger 7, and simultaneously performs a second bypass operation that is sucked into the compressor 5 via the four-way valve 6, thereby heating The outdoor heat exchanger 7 can be defrosted while operating. At this time, since the flow rate adjusting valve 19 is closed, the refrigerant does not flow into the third bypass circuit 18.

  Next, the heating operation will be described.

  As shown in FIG. 3, during the heating operation, the first two-way valve 11 and the second two-way valve 15 are closed, and the flow rate adjustment valve 19 is opened to adjust the opening degree. By such valve operation, the high-temperature and high-pressure refrigerant discharged from the compressor 5 flows into the indoor heat exchanger 3 via the four-way valve 6 switched to the heating operation state, and exchanges heat with indoor air to be condensed and liquefied. The liquefied refrigerant is once decompressed to an intermediate pressure by the first decompressor 30 to be in a gas-liquid two-phase state, and is separated into a gas refrigerant and a liquid refrigerant by the gas-liquid separator. The gas refrigerant flows into the gas injection path 34, and a part of the liquid refrigerant flows into the third bypass circuit 18 by the flow rate adjusting valve 19, is heated by the refrigerant heater 13, and merges with the gas injection path 34, and then the compressor 5 Returned to inhalation. The remaining liquid refrigerant is further decompressed to a low pressure by the second decompressor. The decompressed refrigerant is heat-exchanged with the outside air in the outdoor heat exchanger 7 and evaporated to evaporate, and then merges with the gas refrigerant flowing from the gas injection path 34 via the four-way valve 6 and is sucked into the compressor 5. At this time, since the first two-way valve 11 and the second two-way valve 15 are closed, the refrigerant does not flow through the first and second bypass circuits 14. Further, by controlling the opening and closing of the flow rate adjusting valve 19 according to the size of the heating load by the differential pressure detection means 21 as the heating load detection means 20, it is possible to secure the amount of heat of the heat storage means 12 required during the defrosting operation. it can.

  By flowing a part of the refrigerant through the third bypass circuit 18 during the heating operation as described above, the amount of refrigerant flowing through the outdoor heat exchanger 7 can be reduced and the pressure loss can be reduced. The suction pressure can be increased. Thereby, the input of the compressor 5 can be reduced, heating efficiency can be improved, and energy can be saved.

  The method described in Embodiment 1 can be applied to the opening degree control of the flow rate adjusting valve 19 during the heating operation and the switching control from the heating operation to the defrosting operation.

  With the above configuration, during the heating operation, a part of the refrigerant is bypassed to the third bypass circuit 18, thereby reducing the amount of refrigerant flowing into the outdoor heat exchanger 7 and reducing pressure loss, thereby compressing the refrigerant. The suction pressure of the machine 5 can be increased to improve the heating efficiency and save energy.

(Embodiment 3)
In the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 8 is a configuration diagram illustrating a refrigeration cycle of the air-conditioning apparatus according to Embodiment 3 of the present invention.

  As shown in FIG. 8, a heat pump refrigeration cycle in which a compressor 5, a four-way valve 6, an indoor heat exchanger 3, a decompressor 9, and an outdoor heat exchanger 7 are connected is configured, and the indoor heat exchanger 3 and the decompressor 9 are configured. The first bypass circuit 10 that branches from between and connected to the suction of the compressor 5, the first two-way valve 11 that controls the opening and closing of the first bypass circuit 10, and the refrigerant in the first bypass circuit 10 are heated A refrigerant heater 13 provided with a heat storage means 12, a second bypass circuit 14 branched from between the indoor heat exchanger 3 and the compressor 5 and connected between the decompressor 9 and the outdoor heat exchanger 7, a second The second two-way valve 15 for controlling the opening and closing of the bypass circuit 14 is provided.

  In the third embodiment of the present invention, the first end is connected between the decompressor 9 and the outdoor heat exchanger 7 and the other end is connected to the decompressor 9 side of the outdoor heat exchanger 7 via the refrigerant heater 13. 3 bypass circuit 18, and a third two-way valve 32 between one end and the other end of third bypass circuit 18. Furthermore, the heating load detection means 20 which detects the magnitude of a heating load at the time of heating operation is provided.

  Next, the operating state and the respective valve operations will be described.

  FIG. 9 is a matrix diagram showing the relationship between the operating state and the valve operation in the refrigeration cycle of the air conditioner according to Embodiment 3 of the present invention.

  As shown in FIG. 9, during the cooling operation, the first two-way valve 11 and the second two-way valve 15 are closed, and the third two-way valve 32 is opened. By such valve operation, the high-temperature and high-pressure refrigerant discharged from the compressor 5 flows into the outdoor heat exchanger 7 via the four-way valve 6 switched to the cooling operation state, and exchanges heat with the outside air to be condensed and liquefied. The liquefied refrigerant passes through the third two-way valve 32 and is decompressed by the decompressor 9. At this time, since the flow path loss when the refrigerant flows through the third two-way valve 32 is smaller than the flow path loss when the refrigerant flows through the third bypass circuit 18, most of the refrigerant is the third. Flows to the two-way valve 32 side and does not flow to the third bypass circuit 18. The decompressed refrigerant is evaporated with the indoor heat exchanger 3 through heat exchange with room air, and then sucked into the compressor 5 via the four-way valve 6. At this time, since the first two-way valve 11 and the second two-way valve 15 are closed, the refrigerant does not flow through the first bypass circuit 10 and the second bypass circuit 14.

  Next, a defrosting operation in the case where frost formation has occurred in the outdoor heat exchanger 7 when the outside air temperature is particularly low during the heating operation will be described.

  As shown in FIG. 9, during the defrosting operation, all of the first two-way valve 11, the second two-way valve 15, and the third two-way valve 32 are opened. By this valve operation, a part of the high-temperature refrigerant discharged from the compressor 5 flows into the indoor heat exchanger 3 via the four-way valve 6 switched to the heating operation state, and exchanges heat with indoor air to be condensed and liquefied. . The liquefied refrigerant flows into the first bypass circuit 10, is heated by the refrigerant heater 13, vaporizes and evaporates and is sucked into the compressor 5, and the remaining high-temperature refrigerant discharged from the compressor 5. Flows through the second bypass circuit 14, passes through the third two-way valve 32, is defrosted by exchanging heat with the outdoor heat exchanger 7, and is sucked into the compressor 5 through the four-way valve 6. By performing the bypass operation 2 at the same time, the outdoor heat exchanger 7 can be defrosted while performing the heating operation. At this time, the refrigerant does not flow into the third bypass circuit 18 due to the flow path loss in the same manner as in the cooling operation.

  Next, the heating operation will be described.

  As shown in FIG. 9, during the heating operation, all of the first two-way valve 11, the second two-way valve 15, and the third two-way valve 32 are closed. By such valve operation, the high-temperature and high-pressure refrigerant discharged from the compressor 5 flows into the indoor heat exchanger 3 via the four-way valve 6 switched to the heating operation state, and exchanges heat with indoor air to be condensed and liquefied. The liquefied refrigerant is decompressed by the decompressor 9 to be in a gas-liquid two-phase state, and the third two-way valve 32 is closed, so that all the refrigerant flows into the third bypass circuit 18 and enters the refrigerant heater 13. It becomes a gas-liquid two-phase state heated by the heat storage means 12 provided and having increased in dryness, and flows into the outdoor heat exchanger 7. After evaporating by heat exchange with outside air in the outdoor heat exchanger 7, the air is sucked into the compressor 5 through the four-way valve 6. At this time, since the first two-way valve 11 and the second two-way valve 15 are closed, the refrigerant does not flow through the first and second bypass circuits 14. Further, by controlling the opening and closing of the third two-way valve 32 according to the size of the heating load by the heating load detection means 20, it is possible to ensure the amount of heat of the heat storage means 12 required during the defrosting operation.

  Since all the refrigerant flows through the third bypass circuit 18 during the heating operation as described above, the dryness of the gas-liquid two-phase refrigerant flowing into the outdoor heat exchanger 7 can be increased. By reducing the amount of heat necessary for evaporating the refrigerant in the unit 7 and increasing the suction pressure of the compressor 5, heating efficiency can be improved and energy can be saved.

  FIG. 10 shows an example of another configuration according to the third embodiment of the present invention.

  FIG. 10 is a configuration diagram illustrating another example of the refrigeration cycle of the air conditioner in the refrigeration cycle of the air conditioner according to Embodiment 3 of the present invention.

  As shown in FIG. 10, the third bypass connects one end between the outdoor heat exchanger 7 and the four-way valve 6 and connects the other end to the four-way valve 6 side of the outdoor heat exchanger 7 via the refrigerant heater 13. The circuit 18 and a third two-way valve 32 may be provided between one end and the other end of the third bypass circuit 18. Thereby, since it is not necessary to completely gasify the refrigerant at the outlet of the outdoor heat exchanger 7 during the heating operation, the amount of heat necessary for evaporating the refrigerant in the outdoor heat exchanger 7 is reduced, and the suction pressure of the compressor 5 is reduced. A similar effect can be obtained by raising the value.

  The air conditioner according to the present invention can also be applied to a water heater using a heat pump refrigeration cycle.

DESCRIPTION OF SYMBOLS 1 Indoor unit 2 Outdoor unit 3 Indoor heat exchanger 4 Indoor fan 5 Compressor 6 Four-way valve 7 Outdoor heat exchanger 8 Outdoor fan 9 Decompressor 10 1st bypass circuit 11 1st two-way valve 12 Heat storage means 13 Refrigerant heating 14 Second bypass circuit 15 Second two-way valve 16 Accumulator 17 Three-way valve 18 Third bypass circuit 19 Flow rate adjusting valve 20 Heating load detection means 21 Differential pressure detection means 22 Outside air temperature detection means 23 Outdoor heat exchange temperature detection Means 24 Frosting occurrence detection means 25 Refrigerant heater temperature detection means 26 Flow rate adjusting valve pre-temperature detection means 27 Refrigerant heater outlet temperature detection means 28 Control means 29 Time measurement means 30 First decompressor 31 Second decompressor 32 Third two-way valve 33 Gas-liquid separator 34 Gas injection path

Claims (11)

A heat pump refrigeration cycle in which a compressor, a decompressor, an outdoor heat exchanger, and an indoor heat exchanger are connected by a refrigerant circuit;
During the cooling operation, the direction of the refrigerant flowing through the heat pump refrigeration cycle is changed so that the refrigerant discharged from the compressor passes through the outdoor heat exchanger, the decompressor, and the indoor heat exchanger in this order to the compressor. During the heating operation, the refrigerant discharged from the compressor passes through the indoor heat exchanger, the decompressor, and the outdoor heat exchanger in this order, and returns to the compressor in the second direction. Switching means for switching with,
A first bypass circuit having a first two-way valve and a refrigerant heater, connecting between the indoor heat exchanger and the decompressor and the suction side of the compressor;
A second bypass circuit having a second two-way valve and connecting between the decompressor and the outdoor heat exchanger and a discharge side of the compressor;
A first connecting part provided between the switching means connected to the outdoor heat exchanger from the decompressor and a second connecting part provided between the first connecting part and the suction side of the compressor are connected. 3 bypass circuits,
An air conditioner that heats the refrigerant flowing through the third bypass circuit with the refrigerant heater. A flow control valve;
The air conditioner according to claim 1, wherein the third bypass circuit connects between the pressure reducer and the outdoor heat exchanger and between the first two-way valve and the refrigerant heater. . The decompressor is composed of a first decompressor and a second decompressor,
In the first direction, the refrigerant discharged from the compressor passes through the outdoor heat exchanger, the second decompressor, the first decompressor, and the indoor heat exchanger in this order to the compressor. Back in the first direction,
The second direction is a second direction that passes through the indoor heat exchanger, the first decompressor, the second decompressor, and the outdoor heat exchanger in this order and returns to the compressor,
A gas injection path connecting the gas-liquid separator and the suction side of the compressor, and a flow rate adjusting valve;
2. The air conditioner according to claim 1, wherein the third bypass circuit is connected to the gas injection path through the refrigerant heater from between the gas-liquid separator and the second pressure reducer. .   When the defrosting operation is not performed during the heating operation, the first two-way valve and the second two-way valve are closed, and the opening degree of the flow rate adjustment valve is controlled so that the COP is optimal. The air conditioner according to claim 2 or 3. The third bypass circuit connects one end between the decompressor and the outdoor heat exchanger, and the other end to the decompressor side of the outdoor heat exchanger via the refrigerant heater,
The air conditioner according to claim 1, further comprising a third two-way valve between the one end and the other end of the third bypass circuit. The third bypass circuit has one end between the outdoor heat exchanger and the suction side of the compressor, and the other end between the one end and the suction side of the compressor via the refrigerant heater. Concatenate
The air conditioner according to claim 1, further comprising a third two-way valve between the one end and the other end of the third bypass circuit.   In the heating operation, when the defrosting operation is not performed, control is performed to close the first two-way valve, the second two-way valve, and the third two-way valve. The air conditioner described.   The air conditioner according to any one of claims 1 to 7, wherein the refrigerant heater is a heat storage unit that recovers and stores heat of exhaust heat of the compressor.   A heating load detecting means for detecting the size of the heating load is further provided, and during heating operation, when the heating load detected by the heating load detecting means is larger than a predetermined value, the flow control valve is controlled to be closed, and the heating load is controlled. The air conditioner according to any one of claims 1 to 7, wherein when the heating load detected by the detection means is equal to or less than a predetermined value, control is performed to open the flow rate adjustment valve.   The heating load detecting means is a differential pressure detecting means for detecting a pressure difference in the pipe before and after the flow rate adjusting valve connected to the refrigerant circuit, and when the differential pressure detected by the differential pressure detecting means is larger than a predetermined value. The air conditioner according to claim 9, wherein control is performed to close the flow rate adjustment valve, and control is performed to open the flow rate adjustment valve when the differential pressure detected by the differential pressure detection means is equal to or less than a predetermined value.   The refrigerant heater is a heat storage unit that collects and stores the exhaust heat of the compressor, and further includes a heating load detection unit that detects the size of the heating load, and the heating detected by the heating load detection unit during heating operation. When the load is greater than a predetermined value, control is performed to open the third two-way valve, and when the heating load detected by the heating load detection means is less than a predetermined value, control is performed to close the third two-way valve. The air conditioner according to any one of claims 5 to 7.

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