JP2001280669A - Refrigerating cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of such a case that the stable supply, etc., of a refrigerating capacity is not secured, the number of starting and stopping times of the thermostat of a compressor increases, or the temperature fluctuation in a room increases due to an increase in number of defrosting operations. SOLUTION: A refrigerating cycle device is provided with a first control means 14a which uses a detecting means 11 for detecting the discharge temperature of a compressor, detecting means 10 and 12 for detecting the suction superheat of the compressor, and detecting means 9 and 13 for detecting the subcooling at the outlet of a condenser as sensors and a changing means 6 for changing the heat-exchanging amount of the condenser, a gas by-passing means 7, and a liquid by-passing means 8 as actuators and controls the actuators in a linked state so that the detected values of the sensors may respectively fall within prescribed desired ranges preset at every sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration cycle device used for a refrigerator or an air conditioner, and more particularly to protection of a compressor and securing an appropriate refrigerant temperature in each indoor unit.

[0002]

2. Description of the Related Art A conventional refrigeration cycle apparatus generally comprises
The configuration as shown in FIG. 9 is adopted. In the figure, 1
Is a compressor, 2 is a condenser, 3 is a throttle device, and 4 is an evaporator, which communicates with the annular arrangement to form a main refrigerant circuit. The heat source unit A is configured by the compressor 1, the condenser 2, and the like, and the indoor unit B is configured by the expansion device 3, the evaporator 4, and the like. Reference numeral 5 denotes a refrigerant pipe, which communicates the heat source unit A with one or more indoor units B. In addition to the above, the heat source unit A is provided with actuators such as a fan 6, a gas bypass unit 7, and a liquid bypass unit 8 as a condenser heat exchange amount adjusting unit. Further, sensors such as a compressor discharge pressure detecting means 9, a compressor suction pressure detecting means 10, and a compressor discharge temperature detecting means 11 are also provided. Then, the control means 14A individually controls each actuator so that the detection value of each sensor does not deviate from the respective allowable range. For example, the flow rate of the fan 6 to the condenser 2 is controlled based on the refrigerant discharge pressure detected by the compressor discharge pressure detecting means 9, and the gas flow is controlled based on the refrigerant suction pressure detected by the compressor suction pressure detecting means 10. The opening and closing of the bypass means 7 is controlled, and the liquid bypass means 8 is controlled based on the refrigerant discharge temperature detected by the compressor discharge temperature detecting means 11.
Was controlled to open and close. Further, in the indoor unit B, an operation is performed in which the evaporation pressure of the evaporator 4 is uniquely determined based on the pressure corresponding to the refrigerant suction pressure of the heat source unit A. The conventional refrigeration cycle device is configured as described above,
The environment in which the indoor unit B is installed is refrigerated or air-conditioned while performing protection control for maintaining an appropriate operating range of the compressor 1.

[0003]

Since the conventional refrigeration cycle apparatus is configured as described above, there are the following problems. In particular, in the above-described refrigeration cycle device in which the heat source unit A, the evaporator 4, and the throttle unit 3 are individually and autonomously distributedly controlled, the operating state of the compressor 1 greatly changes with a change in evaporation capacity. There is. In such cases,
A stable supply of refrigeration capacity and a safe operation range of the compressor 1 cannot be ensured, or the frequency of the thermostat of the compressor 1 due to protection control increases, or the frequency of defrost operation due to a decrease in evaporation temperature increases. This may lead to an increase in room temperature change due to the In addition, due to pressure loss or the like in the refrigerant pipe 5, the condensing capacity or the evaporating capacity required in the indoor heat exchanger 4 may be insufficient. Alternatively, when the condensing temperature or the evaporating temperature required by the plurality of indoor side heat exchangers 4 is different, for example, too warm or too cold due to the setting of the highest condensing temperature and the lowest evaporating temperature, or accompanying it In some cases, an increase in the temperature of the room due to an increase in the frequency of the start / stop of the thermostat or an increase in the frequency of the defrost operation may be caused. In addition, simple refrigeration capacity control means is required instead of complicated refrigeration capacity control by capacity control using an inverter or the like.

[0004]

SUMMARY OF THE INVENTION A refrigeration cycle apparatus according to the present invention has been made in order to solve the above-mentioned problems, and has a compressor, a condenser, a throttle means, an evaporator and the like connected in an annular arrangement. A refrigerating cycle device, a compressor discharge temperature detecting means for detecting a refrigerant temperature on a discharge side of the compressor, a compressor suction superheat detecting means for detecting a refrigerant superheat amount on a suction side of the compressor, A condenser heat exchange amount changing means for changing the heat exchange amount of the refrigerant in the condenser by using a condenser outlet subcool detecting means for detecting the refrigerant subcool amount on the outlet side as a sensor, and a discharge side and a suction side of the compressor. Gas bypass means connected between the outlet side of the condenser and the suction side of the compressor, and a liquid bypass connected bypassing the throttling means and the evaporator. And a first control means for controlling each actuator in cooperation with each other such that each detection value of each sensor falls within a predetermined target range preset for each sensor, while using the step as an actuator. Is what it is.

[0005] A refrigeration cycle apparatus according to the present invention comprises:
A refrigerant pipe connects a heat source unit formed by connecting a compressor, a first four-way valve, an outdoor heat exchanger, and the like, and one or more indoor units formed by connecting a throttle unit, an indoor heat exchanger, and the like. In the refrigerating cycle device, the refrigerant pressurizing means for pressurizing the gas refrigerant is provided on the gas refrigerant side of the indoor heat exchanger.

The refrigeration cycle apparatus according to the present invention connects a heat source unit including a compressor, a first four-way valve, an outdoor heat exchanger, and the like, and a throttle unit, an indoor heat exchanger, and the like. In a refrigeration cycle apparatus in which one or a plurality of indoor units are connected by a refrigerant pipe, a refrigerant pressure reducing means for reducing the pressure of the gas refrigerant is provided on the gas refrigerant side of the indoor heat exchanger.

Further, in the refrigeration cycle apparatus according to claim 2, a first bypass means for forming a low pressure loss path when the refrigerant pressurizing means is not used is provided in parallel with the refrigerant pressurizing means.

In the refrigeration cycle apparatus according to the present invention, a refrigerant pressurizing means for pressurizing the refrigerant to flow in one direction and a second four-way valve are provided between the first four-way valve and the indoor heat exchanger. The discharge side of the refrigerant pressurizing means is connected to the high-pressure side inlet of the second four-way valve, and the suction side of the refrigerant pressurizing means is connected to the low-pressure side outlet of the second four-way valve. In this configuration, the refrigerant is bidirectionally switched to flow by switching.

Further, in the refrigeration cycle apparatus according to the third aspect, a second bypass means for forming a low pressure loss path when the refrigerant pressure reducing means is not used is provided in parallel with the refrigerant pressure reducing means.

Further, in the refrigeration cycle apparatus according to claim 2, first pressure detecting means for detecting a pressure equivalent value corresponding to the refrigerant pressure on the indoor heat exchanger side of the refrigerant pressurizing means,
The control amount of the refrigerant pressurizing means is changed so that the detection value of the first pressure detecting means approaches the target pressure value based on the set temperature of the indoor environment temperature and / or the target pressure value based on the actual indoor environment temperature. Control means.

[0011] In the refrigeration cycle apparatus according to the second aspect, the second pressure detecting means for detecting a pressure equivalent value corresponding to the refrigerant pressure on the heat source device side of the refrigerant pressurizing means, and the detected value of the second pressure detecting means. And a third control means for changing the control amount of the refrigerant pressurizing means so as to approach a target pressure value corresponding to the refrigerant pressure on the compressor suction side during the refrigeration / cooling operation by the indoor unit.

In the refrigeration cycle apparatus according to the third aspect, the third pressure detecting means for detecting a pressure equivalent value corresponding to the refrigerant pressure on the indoor side heat exchanger side of the refrigerant pressure reducing means, and the detection by the third pressure detecting means. And a fourth control means for changing the control amount of the refrigerant pressure reducing means so that the value approaches a target pressure value based on the set temperature of the indoor environment temperature and / or a target pressure value based on the actual indoor environment temperature. It is.

Further, in the refrigeration cycle apparatus according to the third aspect, the fourth pressure detecting means for detecting a pressure equivalent value corresponding to the refrigerant pressure on the heat source unit side of the refrigerant pressure reducing means, and the detected value of the fourth pressure detecting means, A fifth control means for changing the control amount of the refrigerant pressure reducing means so as to approach a target pressure value corresponding to the refrigerant pressure on the compressor suction side during the refrigeration / cooling operation by the indoor unit.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings. Embodiment 1 of the Invention FIG. 1 is a configuration diagram illustrating a refrigerant circuit of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. In FIG. 1, 1 is a compressor, 2 is an outdoor heat exchanger (condenser during cooling), 3 is a throttle device, and 4 is an indoor heat exchanger (evaporator during cooling), and these are arranged in a ring. To form a main refrigerant circuit. Here, a heat source unit A is configured by the compressor 1, the condenser 2, and the like, and an indoor unit B is configured by the expansion device 3, the evaporator 4, and the like. Reference numeral 5 denotes a refrigerant pipe, which communicates the heat source unit A with one or more indoor units B. In addition to the above, the heat source unit A includes a fan 6 as a condenser heat exchange amount adjusting unit, and a gas bypass unit connected to the refrigerant circuit between the discharge side and the suction side of the compressor 1 so as to bypass the compressor 1. 7. The outlet side of the outdoor heat exchanger 2 and the compressor 1
An actuator such as a liquid bypass unit 8 connected to the refrigerant circuit between the suction side and the bypass unit 3 and the indoor heat exchanger 4 is provided. The heat source device A includes a compressor discharge pressure detecting means 9 for detecting a refrigerant discharge pressure on a discharge side of the compressor 1, a compressor suction pressure detecting means 10 for detecting a refrigerant pressure on a suction side of the compressor 1, A compressor discharge temperature detecting means 11 for detecting a refrigerant temperature on a discharge side of the compressor 1, a compressor suction temperature detecting means 12 for detecting a refrigerant temperature on a suction side of the compressor 1, and a refrigerant discharge side of the indoor heat exchanger 4; Sensors such as condenser outlet temperature detecting means 13 for detecting the refrigerant temperature are also provided. The actuators are controlled by the control device 14 in association with each other based on the detection values of the sensors.

Here, the cooperative control by the control device 14 will be described. First, compressor discharge temperature, condenser outlet subcool, and compressor suction superheat are taken as parameters of an appropriate operation range of the heat source machine A including the compressor 1. Here, the condenser outlet subcool is obtained from the difference between the detected temperature of the condenser outlet temperature detecting means 13 and the refrigerant saturation temperature corresponding to the detected pressure of the compressor discharge pressure detecting means 9,
Compressor suction superheat is compressor suction temperature detection means 1
2 and the refrigerant saturation temperature corresponding to the pressure detected by the compressor suction pressure detecting means 10. That is, the combination of the condenser outlet temperature detecting means 13, the compressor discharge pressure detecting means 9, and the control device 14 provides a condenser outlet for detecting the refrigerant subcooling amount at the outlet side of the outdoor heat exchanger (condenser) 2. This is an example of a subcool detection unit.
Further, the combination of the compressor suction temperature detecting means 12, the compressor suction pressure detecting means 10, and the control device 14 is an example of a compressor suction superheat detecting means for detecting a refrigerant superheat amount on the suction side of the compressor 1. Becomes

FIG. 2 shows a change in the Mollier diagram of the refrigeration cycle due to the operation of each actuator, depending on the operating conditions and the control amount. In the operation of the gas bypass means 7, as shown in FIG. 7A, the operation in the opening direction of the valve is controlled so as to decrease the compressor discharge temperature, decrease the condenser subcool, and increase the compressor suction superheat. You. In the operation of the liquid bypass means 8, as shown in FIG. 3B, the operation in the opening direction of the valve is controlled such that the compressor discharge temperature decreases, the condensation sub-cool increases, and the compressor suction superheat decreases. You. In the operation of the fan 6 as the condenser heat exchange amount control means, as shown in FIG. 3C, the operation of the fan 6 in the speed increasing direction causes a decrease in the compressor discharge temperature, an increase in the condenser outlet subcool, and an inhalation of the compressor. Controlled in the direction of super heat reduction. In this case, the configuration in which the control device 4 controls the air volume of the fan 6 is an example of a condenser heat exchange amount changing unit that changes the heat exchange amount of the refrigerant in the outdoor heat exchanger 2. As described above, the above three parameters all change due to the control operation of each actuator. Therefore, according to the conventional concept of associating one actuator with one parameter, there is a possibility that the control variable may be oscillating such that it swings without converging toward a target value. Therefore, the following equation is introduced to realize the linkage control based on the following equation.

[0017]

(Equation 1)

Here, a to i in the equations are functions obtained in advance through experiments and the like. Further, by defining a maximum value as the target value-detection value, a sudden change in the control amount is suppressed, and the control based on the above equation is periodically repeated. Also,
The target value has a width within an allowable range to suppress the vibration of the control operation.

As described above, the actuators are linked by the first control means 14a of the control device 14 so that the respective detection values of the sensors fall within a predetermined target range preset for each sensor. Can be controlled. That is, even in a refrigeration cycle in which the heat source unit A, the evaporator 4 and the throttle unit 3 are completely autonomously and decentralized, the change in the evaporation capacity is caused by the joint control by the actuator and the sensor closed in the heat source unit A. As a result, the operating state of the compressor 1 changes significantly, and it becomes impossible to ensure a stable supply of refrigeration capacity and a safe operating range of the compressor 1,
The protection control can solve such a problem that the frequency of starting and stopping thermostat of the compressor 1 increases, or that the indoor temperature change increases due to an increase in the frequency of defrost operation due to a decrease in evaporation temperature. Further, it is possible to realize simple refrigeration capacity control such as gas bypass and liquid bypass instead of complicated refrigeration capacity control by capacity control of an inverter or the like. Here, the detected pressure of the compressor discharge pressure detecting means 9 is used for the control,
It is needless to say that the same control can be performed by using the high-pressure refrigerant saturation temperature detected at the intermediate portion or the like.

Embodiment 2 of the Invention Embodiments corresponding to the inventions of claims 2, 4, 5, 7, and 8 will be described with reference to FIGS. In FIG. 3, reference numeral 1 denotes a compressor, 2 denotes an outdoor heat exchanger, 3 denotes a throttle device, and 4 denotes an indoor heat exchanger, which communicate with an annular arrangement to form a main refrigerant circuit. The heat source unit A is configured by the compressor 1, the outdoor heat exchanger 2, and the like, and the indoor unit B is configured by the expansion device 3, the indoor heat exchanger 4, and the like. Reference numeral 5 denotes a refrigerant pipe, which communicates the heat source unit A with one or more indoor units B.
In addition to the above, the heat source unit A is a first four-way valve 15 that switches the flow direction of the refrigerant in the refrigerant circuit by switching the valve flow path.
It has. In addition to the above, the indoor unit B is provided in a refrigerant circuit on the gas refrigerant side of the indoor heat exchanger 4, and is a refrigerant pressurizing means 16 such as a gas pump that pressurizes the gas refrigerant and allows the gas refrigerant to flow in one direction. The first bypass means 18, which is provided in the refrigerant circuit in parallel with the refrigerant circuit 16 and forms a low pressure loss path when the refrigerant pressurizing means 16 is not in use, switches the flow direction of the refrigerant in the refrigerant circuit in both directions by switching the valve flow path to distribute the refrigerant. Second
A four-way valve 17 is provided. The refrigerant pressurizing means 16 and the second four-way valve 17 are provided in a refrigerant circuit between the first four-way valve 15 and the indoor heat exchanger 4. The discharge side of the refrigerant pressurizing means 16 is connected to the high pressure side inlet 17 a of the second four-way valve 17.
The suction side of the refrigerant pressurizing means 16 is connected to the low pressure side outlet 17b of the second four-way valve 17. The indoor unit B further includes a first pressure detecting unit 19 that detects a pressure equivalent value corresponding to the refrigerant pressure of the refrigerant pressurizing unit 16 on the indoor side heat exchanger 4 side, and a heat source unit A side of the refrigerant pressurizing unit 16. A second pressure detecting means 20 for detecting a pressure equivalent value corresponding to the refrigerant pressure of the refrigerant, and an indoor environment temperature setting means (not shown; the same applies hereinafter) for setting a target indoor environment temperature. I have.

With this configuration, the flow path of the second four-way valve 17 is switched and controlled according to the flow direction of the refrigerant in the indoor unit B, so that the refrigerant pressurizing means 16 always operates in the pressurizing direction. Can be. Also, the refrigerant pressurizing means 16
Is unnecessary, the first bypass means 18 is fully opened, so that the conventional indoor unit B can be operated without pressure loss.

The control operation according to the seventh embodiment will be described with reference to FIG. FIG. 4A shows the case of the cooling operation. In the figure, the second control means 14b of the control device 14 adjusts the first pressure toward the target pressure value based on the set temperature of the indoor environment temperature setting means in each indoor unit B or the target pressure value based on the actual indoor environment temperature. The refrigerant pressurizing means 1 is set so that the pressure detected by the pressure detecting means 19 is approximated.
6 is changed. With such a configuration, an evaporation temperature lower than the refrigerant saturation temperature corresponding to the suction pressure of the compressor 1 in the heat source unit A can be realized for each indoor unit B, and the heat source adapted to the indoor unit B having a high evaporation temperature can be achieved. By the operation of the unit A, it is possible to suppress an increase in the frequency of thermo start / stop and an increase in the frequency of the indoor defrost operation due to the excessive cooling in the indoor unit B.

FIG. 4B shows the case of the heating operation. In the figure, the second control means 14b of the control device 14
Is set so that the detected pressure of the first pressure detecting means 19 approaches the target pressure value based on the set temperature value of the indoor environment temperature setting means or the target pressure value based on the actual indoor environment temperature in each indoor unit B. Then, the pressure control amount of the refrigerant pressurizing means 16 is changed. With this configuration, a condensation temperature higher than the refrigerant saturation temperature corresponding to the discharge pressure of the compressor 1 in the heat source unit A can be realized for each of the indoor units B, and the heat source adapted to the indoor unit B can have a low evaporation temperature. By the operation of the machine A,
It is possible to suppress an increase in the frequency of thermo start / stop caused by excessive heating in the indoor unit B.

The control operation according to the eighth embodiment will be described with reference to FIG. FIG. 5A shows a case of a cooling (freezing) operation. In the figure, a third control unit 14c of the control device 14 calculates a target pressure value obtained by adding a target value of the compressor suction pressure of the heat source unit A to a pressure loss corresponding to the refrigerant pipe 5 connected to each indoor unit B. , So that the pressure detected by the second pressure detecting means 20 is made closer.
Is changed. With such a configuration, the compressor suction pressure in the heat source unit A decreases to deviate from the proper operation range, the amount of circulating refrigerant in the refrigerant circuit decreases, or the indoor amount calculated backward from the heat source unit A side. The evaporation pressure in the machine B does not rise and the temperature difference between the air and the refrigerant in the indoor heat exchanger 4 does not decrease, and the shortage of the evaporation ability required in the indoor heat exchanger 4 can be suppressed. .

FIG. 5B shows the case of the heating operation. In the figure, the third control means 14c of the control device 14 calculates a target pressure value obtained by subtracting a pressure loss corresponding to the refrigerant pipe 5 connected to each indoor unit B from a target value of the compressor discharge pressure of the heat source unit A. , The pressure control amount of the refrigerant pressurizing means 16 is changed so that the detected pressure of the second pressure detecting means 20 approaches. With this configuration, the proper operation range is deviated due to an increase in the compressor discharge pressure or the compressor discharge temperature in the heat source unit A, or the condensation in the indoor unit B is calculated backward from the heat source unit A side. The temperature drops and the indoor heat exchanger 4
In this case, the temperature difference between the air and the refrigerant does not decrease, and the shortage of the condensation capacity required by the indoor heat exchanger 4 can be suppressed.

Embodiment 3 of the Invention Embodiments corresponding to the third, sixth, ninth, and tenth aspects of the present invention will be described with reference to FIGS. In FIG. 6, 1 is a compressor, 2 is an outdoor heat exchanger, 3 is a throttling device, and 4 is an indoor heat exchanger, which communicate with an annular arrangement to form a main refrigerant circuit. The heat source unit A is configured by the compressor 1, the outdoor heat exchanger 2, and the like, and the indoor unit B is configured by the expansion device 3, the indoor heat exchanger 4, and the like. 5 is a refrigerant pipe, which is a heat source unit A
And one or more indoor units B. The heat source device A includes a first four-way valve 15 in addition to the above.
In addition to the above, the indoor unit B is provided in the refrigerant circuit on the gas refrigerant side of the indoor heat exchanger 4, and is provided in the refrigerant circuit in parallel with the refrigerant decompression means 21 and the refrigerant decompression means 21 for decompressing the gas refrigerant. And a second bypass means 22 for forming a low pressure loss path when the refrigerant pressure reducing means 21 is not used. Further, the indoor unit B is connected to the indoor heat exchanger 4 of the refrigerant pressure reducing means 21.
Pressure detecting means 23 for detecting a pressure equivalent value corresponding to the refrigerant pressure on the refrigerant side, second pressure detecting means 24 for detecting the refrigerant pressure in the refrigerant circuit on the heat source device A side of the refrigerant pressure reducing means 21, and detecting the indoor environment temperature Indoor environment temperature detecting means 2
5. It has an indoor environment temperature setting means.

With this configuration, the indoor unit B
In the above, when the refrigerant pressure reducing means 21 is unnecessary, by fully opening the second bypass means 22, it is possible to operate as a conventional indoor unit without pressure loss.

The control operation according to the ninth embodiment will be described with reference to FIG. FIG. 7A shows the case of the cooling operation. In the figure, the fourth control means 14d of the control device 14 sets the third pressure toward the target pressure value based on the set temperature of the indoor environment temperature setting means in each indoor unit B or the target pressure value based on the actual indoor environment temperature. Refrigerant pressure reducing means 2 so that the pressure detected by pressure detecting means
The pressure reduction control amount of 1 is changed. With such a configuration, an evaporation temperature higher than the refrigerant saturation temperature corresponding to the suction pressure of the compressor 1 in the heat source unit A can be realized for each of the indoor units B, and is adjusted to the indoor unit B having a low evaporation temperature. By the operation of the heat source unit A, it is possible to suppress an increase in the frequency of thermo start / stop and an increase in the frequency of the indoor defrost operation due to excessive cooling in the indoor unit B having a high evaporation temperature.

FIG. 7B shows the case of the heating operation. In the figure, the fourth control means 14d of the control device 14 sets the third pressure toward the target pressure value based on the set temperature of the indoor environment temperature setting means in each indoor unit B or the target pressure value based on the actual indoor environment temperature. The pressure reduction control amount of the refrigerant pressure reducing means 21 is changed so that the pressure detected by the pressure detecting means 23 approaches. With such a configuration, a condensation pressure lower than the refrigerant saturation temperature corresponding to the compressor discharge pressure in the heat source unit A can be realized for each indoor unit B, and the heat source unit adapted to the indoor unit B having a high evaporation temperature By the operation of A, it is possible to suppress an increase in the frequency of thermo start / stop caused by excessive heating in the indoor unit B, which is good at a low condensation temperature.

The control operation according to the tenth embodiment will be described with reference to FIG. FIG. 8 shows a case of a cooling (freezing) operation. In the figure, the set value of the indoor environment temperature setting means in each indoor unit B and the indoor environment temperature detection means 2
5 when the difference from the detection value of the control unit 5 becomes small.
The fifth control means 14e reduces the target pressure value corresponding to the compressor suction pressure in the heat source unit A in order to suppress the evaporation capacity of the indoor unit B. Further, the fifth control unit 14e changes the pressure reduction control amount of the refrigerant pressure reduction unit 21 so that the pressure detected by the fourth pressure detection unit 24 approaches the target value. With this configuration, the suction pressure of the compressor 1 in the heat source device A decreases, and the amount of circulating refrigerant in the refrigerant circuit is suppressed. Thereby, the refrigerating capacity can be suppressed. In addition, it is possible to suppress an increase in the frequency of thermo start / stop caused by excessive cooling in the indoor unit B and an increase in the frequency of the indoor defrost operation.

[0031]

According to the present invention having the above-described structure, the following effects can be obtained. That is, according to the first aspect of the present invention, since the cooperative control by each actuator is performed based on the detection value of each sensor, the operating state of the compressor greatly changes with the change of the evaporation capacity. Inability to ensure a stable supply of refrigeration capacity and a safe operating range for the compressor, and increase in indoor temperature change due to an increase in compressor start / stop frequency due to protection control and an increase in defrost operation frequency due to a decrease in evaporation temperature. Can be suppressed.

In addition, the refrigerant pressurizing means is provided on the gas refrigerant side of the indoor heat exchanger as in the invention according to the second, fourth, fifth, seventh and eighth aspects. Insufficient condensing capacity and evaporating capacity required in the indoor heat exchanger can be suppressed. In addition, even if the condensing temperature or evaporating temperature of the indoor heat exchanger required by a plurality of indoor units is different, the target temperature is set to the highest condensing temperature or the lowest evaporating temperature. Alternatively, it is possible to suppress an increase in room temperature change due to an increase in the frequency of thermo start / stop and an increase in the frequency of defrost operation accompanying the change.

Further, by providing the refrigerant pressure reducing means on the gas refrigerant side of the indoor heat exchanger as in the invention according to claims 3, 6, 9 and 10, the room required by a plurality of indoor units is provided. Even if the condensing temperature or evaporating temperature of the inner heat exchanger is different, setting the target temperature to the highest condensing temperature or the lowest evaporating temperature results in overheating or overcooling, or the accompanying increase or decrease in the frequency of thermostats or defrost. It is possible to suppress an increase in indoor temperature change due to an increase in operation frequency or the like.

Further, according to the present invention, the simple refrigerating capacity can be easily obtained by the cooperative control of the gas bypass means and the liquid bypass means, or the control of the refrigerant pressure reducing means of the indoor unit, without depending on complicated capacity control such as capacity control of an inverter or the like. Control means can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a refrigerant circuit of a refrigeration cycle apparatus according to Embodiment 1 of the present invention.

FIGS. 2A and 2B are diagrams for explaining the operation of the refrigeration cycle apparatus according to the first embodiment, in which FIG. 2A is a ph diagram for controlling a gas bypass unit, and FIG. FIG. 3C is a ph diagram when controlling, and FIG. 3C is a ph diagram when controlling the condenser heat exchange amount changing means.

FIG. 3 is a configuration diagram illustrating a refrigerant circuit of a refrigeration cycle apparatus according to Embodiment 2 of the present invention.

4A and 4B are diagrams for explaining the operation of the refrigeration cycle apparatus according to Embodiment 2; FIG.
An h diagram, (b) is a ph diagram at the time of a heating operation.

5A and 5B are diagrams for explaining another operation of the refrigeration cycle device according to the second embodiment, where FIG. 5A is a ph diagram during a cooling operation, and FIG. FIG.

FIG. 6 is a configuration diagram illustrating a refrigerant circuit of a refrigeration cycle apparatus according to Embodiment 3 of the present invention.

FIGS. 7A and 7B are diagrams for explaining the operation of the refrigeration cycle apparatus according to Embodiment 3; FIG.
An h diagram, (b) is a ph diagram at the time of a heating operation.

FIG. 8 is a ph diagram for explaining another operation during the cooling operation in the refrigeration cycle apparatus of the third embodiment.

FIG. 9 is a configuration diagram showing a conventional refrigerant circuit.

[Explanation of symbols]

1 compressor, 2 outdoor heat exchanger (condenser), 3 expansion device, 4 indoor heat exchanger (evaporator), 5 refrigerant piping,
Reference Signs List 6 fan, 7 gas bypass means, 8 liquid bypass means, 9 compressor discharge pressure detecting means, 10 compressor suction pressure detecting means, 11 compressor discharge temperature detecting means, 12 compressor suction temperature detecting means, 13 condenser outlet temperature Detection means, 14 control device, 14a first control means, 14b
Second control means, 14c Third control means, 14d Fourth control means, 14e Fifth control means, 15 First four-way valve, 1
6 refrigerant pressurizing means, 17 second four-way valve, 17a high pressure side inlet, 17b low pressure side outlet, 18 first bypass means,
19 first pressure detecting means, 20 second pressure detecting means, 2
1 refrigerant decompression means, 22 second bypass means, 23 third
Pressure detecting means, 24 Fourth pressure detecting means, 25 Indoor environment temperature detecting means, A heat source unit, B Indoor unit.

Claims (10)

[Claims] In a refrigeration cycle apparatus in which a compressor, a condenser, a throttle means, an evaporator, and the like are connected in an annular arrangement, a compressor discharge temperature detecting means for detecting a refrigerant temperature on a discharge side of the compressor; The compressor suction superheat detecting means for detecting the refrigerant superheat amount on the suction side of the compressor, and the condenser outlet subcool detection means for detecting the refrigerant subcool amount on the outlet side of the condenser, respectively, as the sensors, Condenser heat exchange amount changing means for changing the heat exchange amount of the refrigerant in the compressor, gas bypass means connected around the compressor between a discharge side and a suction side of the compressor, and an outlet side of the condenser. And a liquid bypass means connected between the suction side of the compressor and the bypass means bypassing the evaporator, respectively, as actuators. A refrigeration cycle apparatus comprising: first control means for controlling each of the actuators in cooperation with each other such that respective detection values of the sensors fall within a predetermined target range preset for each of the sensors. . 2. A heat source unit connected to a compressor, a first four-way valve, an outdoor heat exchanger and the like, and one or more indoor units connected to a throttle unit, an indoor heat exchanger and the like. Refrigeration cycle apparatus, wherein a refrigerant pressure means for pressurizing the gas refrigerant is provided on the gas refrigerant side of the indoor heat exchanger. 3. A heat source unit connected to a compressor, a first four-way valve, an outdoor heat exchanger and the like, and one or more indoor units connected to a throttle means, an indoor heat exchanger and the like. Refrigeration cycle device, wherein refrigerant decompression means for decompressing the gas refrigerant is provided on the gas refrigerant side of the indoor heat exchanger. 4. The refrigeration cycle according to claim 2, further comprising a first bypass unit that forms a low pressure loss path when the refrigerant pressurization unit is not used, in parallel with the refrigerant pressurization unit. apparatus. 5. A refrigerant pressurizing means for pressurizing a refrigerant to flow in a unidirectional manner, and a second four-way valve are provided between the first four-way valve and the indoor heat exchanger. Side the second
While connected to the high pressure side inlet of the four-way valve, the suction side of the refrigerant pressurizing means is connected to the low pressure side outlet of the second four-way valve,
3. A structure in which the refrigerant is bidirectionally switched and circulated by switching the flow path of the second four-way valve.
A refrigeration cycle apparatus according to the paragraph. 6. The refrigeration cycle apparatus according to claim 3, further comprising a second bypass unit that forms a low pressure loss path when the refrigerant decompression unit is not used, in parallel with the refrigerant decompression unit. 7. A first pressure detecting means for detecting a pressure equivalent value corresponding to the refrigerant pressure on the indoor heat exchanger side of the refrigerant pressurizing means, and detecting the detected value of the first pressure detecting means as an indoor environment temperature. A second control means for changing a control amount of the refrigerant pressurizing means so as to approach a target pressure value based on a set temperature and / or a target pressure value based on an actual indoor environment temperature. Item 3. A refrigeration cycle apparatus according to Item 2. 8. A second pressure detecting means for detecting a pressure equivalent value corresponding to a refrigerant pressure on a heat source unit side of the refrigerant pressurizing means, and a refrigeration / cooling operation by an indoor unit based on the detected value of the second pressure detecting means. 3. The apparatus according to claim 2, further comprising: third control means for changing a control amount of the refrigerant pressurizing means so as to approach a target pressure value corresponding to the refrigerant pressure on the compressor suction side at the time. A refrigeration cycle apparatus as described in the above. 9. A third pressure detecting means for detecting a pressure equivalent value corresponding to a refrigerant pressure on the indoor heat exchanger side of the refrigerant depressurizing means, and a detection value of the third pressure detecting means is set to an indoor environment temperature. A fourth control means for changing a control amount of the refrigerant pressure reducing means so as to approach a target pressure value based on a temperature and / or a target pressure value based on an actual indoor environment temperature. Item 4. The refrigeration cycle device according to item 3. 10. A fourth pressure detecting means for detecting a pressure equivalent value corresponding to the refrigerant pressure on the heat source side of the refrigerant pressure reducing means, and detecting the detected value of the fourth pressure detecting means during a refrigeration / cooling operation by an indoor unit. 5. The apparatus according to claim 3, further comprising: fifth control means for changing a control amount of the refrigerant pressure reducing means so as to approach a target pressure value corresponding to the refrigerant pressure on the compressor suction side. Refrigeration cycle device.