JP2009014210A - Refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve convergence in capacity control in a refrigerating device performing a supercritical cycle. <P>SOLUTION: An air conditioning device 10 comprises a refrigerant circuit 20 constituted by successively connecting a compressor 21, an outdoor heat exchanger 23, an outdoor expansion valve 24 and an indoor heat exchanger 27, and performing the supercritical refrigerating cycle where high pressure is at a critical pressure of the refrigerant or higher, and a controller 40 controlling controlling objects including at least the compressor 21 and the outdoor expansion valve 24. The controller 40 simultaneously controls the plurality of controlling objects to simultaneously control prescribed physical quantities as barometer of the capacity of the refrigerating device and high pressure of the refrigerating cycle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus including a refrigerant circuit that performs a supercritical cycle.

  In a refrigeration apparatus having a refrigerant circuit in which a compression mechanism, a heat source side heat exchanger, an expansion mechanism, and a use side heat exchanger are connected in order, the capacity of the refrigeration apparatus is controlled by controlling the compression mechanism and the expansion mechanism. It is common to control. One example of such a refrigeration apparatus is disclosed in Patent Document 1.

The refrigeration apparatus disclosed in Patent Document 1 includes compressor capacity control means for controlling the capacity of a compressor as a compression mechanism, and expansion valve opening degree control means for controlling the valve opening degree of an expansion valve as an expansion mechanism. It has. The compressor capacity control means controls the capacity of the compressor based on the low pressure of the refrigerant in the refrigerant circuit. The expansion valve opening degree control means controls the opening degree of the expansion valve based on the refrigerant temperature at the evaporator outlet. At this time, the control amount of the expansion valve opening control means is corrected based on the capacity of the compressor.
JP 2002-22242 A

  However, even if the expansion valve opening degree control means corrects the control amount of the expansion valve opening degree based on the capacity of the compressor, if the expansion valve opening degree is changed, the circulation state of the refrigerant is changed. Due to the change, a change also occurs in the low pressure of the refrigerant. When the low pressure of the refrigerant changes, the capacity of the compression mechanism is adjusted by the compressor capacity control means. Thus, when the capacity of the compressor changes, it becomes necessary to correct the control amount by the expansion valve opening degree control means again. As a result, the correction of the control amount of the expansion valve opening control means, the change of the low pressure of the refrigerant, the change of the capacity of the compressor, the correction of the control amount of the expansion valve opening control means again, and so on. There is a problem that the low-pressure control by the superheater and the superheat control by the expansion valve do not converge easily.

  In particular, in a refrigeration apparatus that performs a supercritical refrigeration cycle in which the high pressure is equal to or higher than the critical pressure of the refrigerant, the convergence of this control is poor and becomes a problem.

  This invention is made | formed in view of this point, The place made into the objective is to improve the convergence of the capability control in the freezing apparatus which performs a supercritical cycle.

The present invention has been made paying attention to the fact that the amount of change in the enthalpy of the refrigerant at the outlet of the gas cooler is large with respect to the change in high pressure in the supercritical cycle. Specifically, in the supercritical cycle, when the high pressure is changed due to the low pressure fluctuation in the cooling operation, the enthalpy of the refrigerant at the gas cooler outlet may be greatly changed. As a result, the enthalpy of the refrigerant at the inlet of the indoor heat exchanger changes, thereby adding an effect not found in the subcritical refrigerant that the degree of superheat at the outlet of the indoor heat exchanger changes, and the convergence of control is further deteriorated. When the high pressure changes even during heating, the enthalpy of the refrigerant at the gas cooler outlet may change greatly.As a result, the indoor capacity increases and decreases, and the room temperature fluctuates. The convergence of control deteriorates in a vicious circle in which the target value changes. In addition, in CO ₂ which is a supercritical refrigerant, the density change of the refrigerant when the degree of superheat is larger than that of chlorofluorocarbon (for example, when the superheat degree changes from 0 ° C. to 5 ° C. at an evaporation temperature of 5 ° C.) , whereas the gas density in R410A is not reduced only 3.5%, decreases also CO 6.5% in _2), because the degree of superheat is greater changes in circulating volume and capacity by changing, more control The effect on sex is increased. In view of this, the present invention controls both the high pressure of the refrigeration cycle and a predetermined physical quantity controlled by capacity control.

  Specifically, in the first invention, the compression mechanism (21), the heat source side heat exchanger (23), the expansion mechanism (24), and the use side heat exchanger (27) are connected in order so that the high pressure is reduced. A refrigeration apparatus comprising a refrigerant circuit (20) that performs a supercritical refrigeration cycle that is equal to or higher than a critical pressure, and a control means (40) that controls a control target including at least the compression mechanism (21) and the expansion mechanism (24) Is the target. And the said control means (40) shall control both the predetermined | prescribed physical quantity in a freezing apparatus, and the high voltage | pressure of a refrigerating cycle by controlling the said several control object together.

  In the case of the above configuration, the predetermined physical quantity is controlled while controlling the high pressure of the refrigeration cycle in the refrigerant circuit (20). That is, other physical quantities can be controlled in consideration of a change in the high pressure of the refrigeration cycle when the control target is adjusted, and a change in the enthalpy of the refrigerant at the gas cooler outlet. In this way, by controlling both the high pressure of the refrigeration cycle and the predetermined physical quantity by controlling a plurality of controlled objects together, the control is performed in consideration of the influence on the high pressure and the predetermined physical quantity caused by the mutual changes. Since the target can be controlled, the controlled object is controlled separately, and the high pressure and the predetermined physical quantity of the corresponding refrigeration cycle are changed separately to affect each other and prevent the situation where it does not converge easily Can do. As a result, it is possible to improve the convergence of a predetermined physical quantity and high pressure control in the refrigeration apparatus.

  In a second aspect based on the first aspect, the control means (40) receives the predetermined physical quantity and the high pressure of the refrigeration cycle as input, and outputs a control signal for each of the plurality of control objects to the physical quantity and the high pressure. Are generated in association with each other, and the control signal is output to each control target, thereby controlling both the predetermined physical quantity and the high pressure of the refrigeration cycle.

  In the case of the above-described configuration, a control signal for controlling each of the plurality of control objects is generated by inputting a predetermined physical quantity and a high pressure of the refrigeration cycle in association with each other, thereby generating a predetermined physical quantity or high pressure. Instead of controlling any one of these as an input, it is possible to control each controlled object in consideration of both a predetermined physical quantity and a high pressure. Furthermore, since a plurality of control objects are controlled together as described above, when generating a control signal for one control object, the control signal also takes into account the influence on the predetermined physical quantity and high voltage due to the adjustment of the other control object. Can be generated.

  A third invention further includes a heat source side fan (28) for supplying air to the heat source side heat exchanger (23) for exchanging heat between the refrigerant and air in the first or second invention, and during cooling operation. The predetermined physical quantities are the refrigerant evaporation temperature in the use side heat exchanger (27) and the degree of superheat of the refrigerant at the outlet of the use side heat exchanger (27). A heat source side fan (28) is further included, and the control means (40) receives the evaporating temperature and superheat degree of the refrigerant and the high pressure of the refrigeration cycle as inputs, and the compression mechanism (21), expansion mechanism ( 24) and the heat source side fan (28) are controlled together to control both the evaporating temperature of the refrigerant, the superheat degree of the refrigerant, and the high pressure of the refrigeration cycle.

  In the case of the above-described configuration, during the cooling operation, the refrigerant evaporates while controlling the high pressure of the refrigeration cycle by controlling the three control objects of the compression mechanism (21), the expansion mechanism (24) and the heat source side fan (28) together. By controlling both the temperature and the degree of superheat, the refrigerant evaporating temperature and the degree of superheat can be controlled while stably controlling the high pressure of the refrigeration cycle to a desired target value. The evaporation temperature and superheat degree of the refrigerant can be controlled with high convergence.

  According to a fourth invention, in the first or second invention, during the heating operation, the predetermined physical quantity is a degree of superheat of the refrigerant at an outlet of the heat source side heat exchanger (23), and the control means (40) Controls both the superheat degree of the refrigerant and the high pressure of the refrigeration cycle by controlling both the compression mechanism (21) and the expansion mechanism (24) with the superheat degree of the refrigerant and the high pressure of the refrigeration cycle as inputs. It shall be.

  In the case of the above-described configuration, during heating operation, by controlling both the compression target (the compression mechanism (21) and the expansion mechanism (24)) and controlling the high pressure of the refrigeration cycle, the superheat degree of the refrigerant is controlled together. Since the superheat degree of the refrigerant can be controlled in a state where the high pressure of the refrigeration cycle is stably controlled to a desired target value, the high pressure of the refrigeration cycle and the superheat degree of the refrigerant can be controlled with high convergence.

  In a fifth aspect based on the first or second aspect, the compression mechanism is discharged from the first compressor (21a) that sucks and compresses the low-pressure refrigerant, and the first compressor (21a). A second compressor (21b) that further compresses and discharges the refrigerant, and the expansion mechanism includes a first expansion mechanism (24) that expands the high-pressure refrigerant and an intermediate between the first expansion mechanism (24). A second expansion mechanism (26) that further expands the refrigerant that has become a pressure, and during the cooling operation, the predetermined physical quantity is determined by the refrigerant evaporation temperature and the utilization in the utilization side heat exchanger (27). The refrigerant superheat degree at the outlet of the side heat exchanger (27) and the intermediate pressure of the refrigeration cycle, and the control means (240) includes the evaporating temperature of the refrigerant, the superheat degree of the refrigerant, and the intermediate pressure of the refrigeration cycle. Using the high pressure of the refrigeration cycle as an input, the first and second compressors (21a, 21b) are arranged By controlling the first and second expansion mechanism (24, 26) together, and to control the evaporation temperature of the refrigerant, the high pressure of the intermediate pressure and the refrigeration cycle of the degree of superheat and refrigeration cycle of the refrigerant together.

  In the case of the above-described configuration, during the cooling operation, the four controlled objects of the first and second compressors (21a, 21b) and the first and second expansion mechanisms (24, 26) are controlled together to increase the pressure of the refrigeration cycle. By controlling the evaporating temperature, superheat, and intermediate pressure of the refrigerant together while controlling the refrigerant, the evaporating temperature, superheat, and refrigeration cycle of the refrigerant are controlled while the high pressure of the refrigeration cycle is stably controlled to a desired target value. Since the intermediate pressure can be controlled, the high pressure of the refrigeration cycle, the evaporation temperature of the refrigerant, the degree of superheat, and the intermediate pressure of the refrigeration cycle can be controlled with high convergence.

  In a sixth aspect based on the first or second aspect, the compression mechanism is discharged from the first compressor (21a) that sucks and compresses the low-pressure refrigerant, and the first compressor (21a). A second compressor (21b) that further compresses and discharges the refrigerant, and the expansion mechanism includes a first expansion mechanism (24) that expands the high-pressure refrigerant and an intermediate between the first expansion mechanism (24). A second expansion mechanism (26) that further expands the refrigerant that has become a pressure, and during the heating operation, the predetermined physical quantity is the refrigerant evaporation temperature and the heat source in the heat source side heat exchanger (23). A degree of superheat of the refrigerant at the outlet of the side heat exchanger (23) and a gas cooler outlet temperature which is the temperature of the refrigerant at the outlet of the utilization side heat exchanger (27), and the control means (240) Evaporation temperature, refrigerant superheat, refrigerant gas cooler outlet temperature and refrigeration cycle And controlling the first and second compressors (21a, 21b) and the first and second expansion mechanisms (24, 26) as inputs, the evaporating temperature of the refrigerant and the overheating of the refrigerant. And the temperature of the gas cooler outlet of the refrigerant and the high pressure of the refrigeration cycle are both controlled.

  In the case of the above-described configuration, during the heating operation, the four controlled objects of the first and second compressors (21a, 21b) and the first and second expansion mechanisms (24, 26) are controlled together to increase the pressure of the refrigeration cycle. The refrigerant evaporation temperature, superheat, and gas cooler outlet are controlled in a state where the high pressure of the refrigeration cycle is stably controlled to a desired target value by controlling the refrigerant evaporation temperature, superheat, and gas cooler outlet temperature together. Since the temperature can be controlled, the high pressure of the refrigeration cycle, the evaporation temperature of the refrigerant, the superheat degree, and the gas cooler outlet temperature can be controlled with high convergence.

  A seventh invention is the first or second invention, wherein a plurality of the use side heat exchangers (27a, 27b) are provided and connected in parallel to each other, and the expansion mechanism A plurality of utilization side expansion mechanisms (26a, 26b) provided corresponding to the respective side heat exchangers (27a, 27b), the utilization side heat exchangers (27a, 27b), and the utilization side expansion mechanisms (26a, 26b). 26b) and a heat source side heat exchanger (23) provided between the heat source side heat exchanger (23), and during the cooling operation, the predetermined physical quantity is the use side heat exchanger ( 27a, 27b) and the refrigerant evaporating temperature and the degree of superheat of the refrigerant at the outlet of each use side heat exchanger (27a, 27b), and the control means (340) The compression mechanism (21) includes a plurality of superheat degrees of the refrigerant in the side heat exchangers (27a, 27b) and the high pressure of the refrigeration cycle as inputs. By controlling both the use side expansion mechanism (26a, 26b) and the heat source side expansion mechanism (24), the evaporating temperature of the refrigerant and the degree of superheat of the refrigerant in each use side heat exchanger (27a, 27b) And the high pressure of the refrigeration cycle.

  In the case of the above-described configuration, during the cooling operation, a plurality of controlled objects such as the compression mechanism (21), the heat source side expansion mechanism (24), and the plurality of usage side expansion mechanisms (26a, 26b) are controlled together to increase the pressure of the refrigeration cycle. By controlling both the evaporating temperature of the refrigerant and the degree of superheat in each use-side heat exchanger (27a, 27b) while controlling the refrigerant, the high pressure of the refrigeration cycle is stably controlled to the desired target value. Since the evaporation temperature and the degree of superheat in each use side heat exchanger (27a, 27b) can be controlled, the high pressure of the refrigeration cycle, the evaporation temperature of the refrigerant, and the degree of superheat in each use side heat exchanger (27a, 27b) Can be controlled with high convergence.

  An eighth invention is the first or second invention, wherein a plurality of the use side heat exchangers (27a, 27b) are provided and connected in parallel to each other, and the expansion mechanism A plurality of utilization side expansion mechanisms (26a, 26b) provided corresponding to the respective side heat exchangers (27a, 27b), the utilization side heat exchangers (27a, 27b), and the utilization side expansion mechanisms (26a, 26b). 26b) and a heat source side heat exchanger (23) provided between the heat source side heat exchanger (23), and during the heating operation, the predetermined physical quantity is the heat source side heat exchanger ( 23) and the gas cooler outlet temperature, which is the temperature of the refrigerant at the outlet of each use side heat exchanger (27a, 27b), and the control means (340) And the gas cooler outlet temperature of the refrigerant and the high pressure of the refrigeration cycle in each of the use side heat exchangers (27a, 27b) By controlling the compression mechanism (21), the plurality of use side expansion mechanisms (26a, 26b) and the heat source side expansion mechanism (24) together, the superheat degree of the refrigerant and each use side heat exchanger are controlled. It is assumed that both the gas cooler outlet temperature of the refrigerant in (27a, 27b) and the high pressure of the refrigeration cycle are controlled.

  In the case of the above-described configuration, during heating operation, a plurality of controlled objects such as the compression mechanism (21), the heat source side expansion mechanism (24), and the plurality of usage side expansion mechanisms (26a, 26b) are controlled together to increase the pressure of the refrigeration cycle. Controlling both refrigerant superheat and refrigerant gas cooler outlet temperature in each heat exchanger (27a, 27b) while controlling the high pressure of the refrigeration cycle to the desired target value Can control the refrigerant superheat degree and the refrigerant gas cooler outlet temperature in each use side heat exchanger (27a, 27b), so that the high pressure of the refrigeration cycle, the refrigerant superheat degree, and each use side heat exchanger (27a 27b), the refrigerant gas cooler outlet temperature can be controlled with high convergence.

  According to the present invention, a plurality of objects to be controlled are controlled together to control both a predetermined physical quantity in the refrigeration apparatus and a high pressure of the refrigeration cycle, thereby considering both the predetermined physical quantity and the high pressure of the refrigeration cycle. Since the predetermined physical quantity and the high pressure of the refrigeration cycle can be controlled in consideration of the mutual influences of the controlled objects, the convergence of the predetermined physical quantity and high pressure control in the refrigeration apparatus can be improved.

  According to the second invention, a control signal for controlling each of the plurality of control targets is generated by inputting a predetermined physical quantity and a high pressure of the refrigeration cycle in association with each other, thereby generating one control target. When generating the control signal, in addition to considering both the predetermined physical quantity and the high pressure of the refrigeration cycle, the control signal is also generated in consideration of the influence on the predetermined physical quantity and high pressure due to the adjustment of other control targets. It is possible to improve the convergence of a predetermined physical quantity and high-pressure control in the refrigeration apparatus.

  According to the third invention, during the cooling operation, the three control objects of the compression mechanism (21), the expansion mechanism (24), and the heat source side fan (28) are controlled together to control the high pressure of the refrigeration cycle. By controlling both the evaporation temperature and the degree of superheat, the high pressure of the refrigeration cycle, the evaporation temperature of the refrigerant, and the degree of superheat can be controlled with high convergence.

  According to the fourth aspect of the present invention, during the heating operation, the two control objects of the compression mechanism (21) and the expansion mechanism (24) are controlled together to control the superheat degree of the refrigerant while controlling the high pressure of the refrigeration cycle. Thus, the high pressure of the refrigeration cycle and the degree of superheat of the refrigerant can be controlled with high convergence.

  According to the fifth invention, in the refrigeration apparatus that performs the two-stage compression refrigeration cycle, during the cooling operation, the first and second compressors (21a, 21b) and the first and second expansion mechanisms (24, 26) 4 By controlling both the control target and the high pressure of the refrigeration cycle while simultaneously controlling the refrigerant evaporating temperature and superheat degree and the intermediate pressure of the refrigeration cycle, the refrigeration cycle high pressure, refrigerant evaporating temperature, superheat degree and The intermediate pressure of the refrigeration cycle can be controlled with high convergence.

  According to the sixth invention, in the refrigeration apparatus that performs the two-stage compression refrigeration cycle, during the heating operation, the first and second compressors (21a, 21b) and the first and second expansion mechanisms (24, 26) 4 By controlling both the refrigerant temperature, superheat and gas cooler outlet temperature while controlling the high pressure of the refrigeration cycle by controlling two control objects together, the high pressure of the refrigeration cycle, the refrigerant evaporation temperature, the superheat and the gas cooler outlet The temperature can be controlled with high convergence.

  According to the seventh invention, in a so-called multi-machine provided with a plurality of indoor units, the cooling mechanism is referred to as a compression mechanism (21), a heat source side expansion mechanism (24), and a plurality of use side expansion mechanisms (26a, 26b). By controlling both of the objects to be controlled and controlling the high temperature of the refrigeration cycle while controlling the evaporation temperature of the refrigerant and the degree of superheat in each use side heat exchanger (27a, 27b), It is possible to control the evaporation temperature and the degree of superheat in each use side heat exchanger (27a, 27b) with high convergence.

  According to the eighth invention, in a so-called multi-machine provided with a plurality of indoor units, the heating mechanism is referred to as a compression mechanism (21), a heat source side expansion mechanism (24), and a plurality of use side expansion mechanisms (26a, 26b). By controlling both the controlled objects together and controlling the high pressure of the refrigeration cycle, the superheat degree of the refrigerant and the refrigerant gas cooler outlet temperature in each use side heat exchanger (27a, 27b) are controlled together. The high pressure, the degree of superheat of the refrigerant, and the gas cooler outlet temperature of the refrigerant in each use side heat exchanger (27a, 27b) can be controlled with high convergence.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment 1 of the Invention
Embodiments of the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the air conditioner (10) of this embodiment includes a refrigerant circuit (20) and a controller (40).

The refrigerant circuit (20) is a closed circuit filled with carbon dioxide (CO ₂ ) as a refrigerant. The refrigerant circuit (20) is configured to perform a vapor compression refrigeration cycle by circulating the refrigerant. The refrigerant circuit (20) performs a supercritical refrigeration cycle (that is, a refrigeration cycle including a vapor pressure region higher than the critical temperature of carbon dioxide) in which the high pressure is set to a value equal to or higher than the critical pressure of carbon dioxide. It is configured.

  The refrigerant circuit (20) includes a compressor (21), a four-way switching valve (22), an outdoor heat exchanger (23), an outdoor expansion valve (24), and an indoor heat exchanger (27). Is connected.

  Specifically, in the refrigerant circuit (20), the compressor (21) has a discharge side connected to the first port of the four-way switching valve (22) and a suction side connected to the second port of the four-way switching valve (22). Has been. In the refrigerant circuit (20), the outdoor heat exchanger (23), the outdoor expansion valve (24), and the indoor heat exchanger (27) are sequentially arranged from the third port to the fourth port of the four-way switching valve (22). ) Are arranged in order.

  The compressor (21) is a variable capacity type so-called hermetic type. The compressor (21) compresses and discharges the sucked refrigerant (carbon dioxide) to the critical pressure or more. By changing the frequency of the alternating current supplied to the motor (not shown) of the compressor (21), the rotational speed, that is, the capacity of the compressor (21) can be changed. This compressor (21) constitutes a compression mechanism.

  In the outdoor heat exchanger (23), the outdoor air taken in by the outdoor fan (28) and the refrigerant exchange heat. In the indoor heat exchanger (27), the indoor air taken in by the indoor fan (29) and the refrigerant exchange heat. The outdoor heat exchanger (23) constitutes a heat source side heat exchanger, and the indoor heat exchanger (27) constitutes a use side heat exchanger. The outdoor fan (28) constitutes a heat source side fan.

  The outdoor expansion valve (24) is constituted by a variable opening electronic expansion valve whose valve body (not shown) is driven by a pulse motor (not shown). This outdoor expansion valve (24) constitutes an expansion mechanism.

  The four-way selector valve (22) includes a first state (state indicated by a solid line in FIG. 1) in which the first port and the third port communicate with each other and the second port and the fourth port communicate with each other, It is possible to switch to a second state (state indicated by a broken line in FIG. 1) in which the four ports communicate and the second port and the third port communicate.

  That is, the air conditioner (10) can be switched between a cooling operation and a heating operation by switching the four-way switching valve (22).

  During the cooling operation, the four-way selector valve (22) is set to the first state. When the compressor (21) is operated in this state, the outdoor heat exchanger (23) becomes a radiator (gas cooler), and each indoor heat exchanger (27) becomes an evaporator to perform a refrigeration cycle. Specifically, the supercritical refrigerant discharged from the compressor (21) flows into the outdoor heat exchanger (23) and radiates heat to the outdoor air. The radiated refrigerant is expanded (depressurized) when passing through the outdoor expansion valve (24) and flows to the indoor heat exchanger (27). In the indoor heat exchanger (27), the refrigerant absorbs heat from the room air and evaporates, and the cooled room air is supplied to the room. The evaporated refrigerant is sucked into the compressor (21) and compressed.

  During the heating operation, the four-way selector valve (22) is set to the second state. When the compressor (21) is operated in this state, the indoor heat exchanger (27) becomes a radiator (gas cooler), and the outdoor heat exchanger (23) becomes an evaporator to perform a refrigeration cycle. Specifically, the supercritical refrigerant discharged from the compressor (21) flows into the indoor heat exchanger (27) and radiates heat to the indoor air. Thereby, the heated indoor air is supplied indoors. The radiated refrigerant expands (depressurizes) when passing through the outdoor expansion valve (24). The refrigerant expanded by the outdoor expansion valve (24) flows into the outdoor heat exchanger (23), absorbs heat from the outdoor air, and evaporates. The evaporated refrigerant is sucked into the compressor (21) and compressed.

  In the air conditioner (10) configured as described above, the refrigerant circuit (20) includes an outside air temperature sensor (30), an indoor temperature sensor (31), a low pressure sensor (32), and a discharge temperature sensor ( 33), a high pressure sensor (34), a heating gas cooler outlet temperature sensor (37), and a cooling gas cooler outlet temperature sensor (39).

  The outdoor temperature sensor (30) is a temperature detection means for detecting the temperature of the outdoor air taken into the outdoor heat exchanger (23). The indoor temperature sensor (31) is temperature detection means for detecting the temperature of the indoor air taken into the indoor heat exchanger (27). The low pressure sensor (32) is temperature detection means for detecting the pressure of the refrigerant sucked into the compressor (21), that is, the low pressure of the refrigeration cycle in the refrigerant circuit (20). The discharge temperature sensor (33) is temperature detection means for detecting the temperature of the refrigerant discharged from the compressor (21). The high pressure sensor (34) is temperature detection means for detecting the pressure of the refrigerant discharged from the compressor (21), that is, the high pressure of the refrigeration cycle in the refrigerant circuit (20). The heating gas cooler outlet temperature sensor (37) is a temperature detecting means for detecting the outlet refrigerant temperature of the indoor heat exchanger (27) when the refrigerant circulates in the heating cycle in the refrigerant circuit (220). The cooling-time gas cooler outlet temperature sensor (39) is a temperature detecting means for detecting the outlet refrigerant temperature of the outdoor heat exchanger (23) when the refrigerant circulates in the cooling cycle in the refrigerant circuit (220).

  The controller (40) receives the output signals of the indoor temperature sensor (31), the low pressure sensor (32), the discharge temperature sensor (33) and the high pressure sensor (34), and the operating frequency of the compressor (21), The opening of the outdoor expansion valve (24) and the operating frequency of the outdoor fan (28) are controlled. This controller (40) constitutes a control means.

  As shown in FIGS. 2 and 3, the controller (40) includes a target low-pressure calculation unit (41) that calculates a target low-pressure Pls that is a low-pressure target value of the refrigeration cycle, and a target that is a high-pressure target value of the refrigeration cycle. A target high pressure calculation unit (42) for calculating the high pressure Phs, a target discharge temperature calculation unit (43) for calculating a target discharge temperature T1s which is a target value of the refrigerant discharge temperature, a compressor (21), an outdoor expansion valve ( 24) and a control signal generator (49) for generating a control signal to the outdoor fan (28). Note that the controller (40) has different control contents in the cooling operation and the heating operation, that is, since the functioning elements are different, the control block diagram during the cooling operation is shown in FIG. 2, and the control block diagram during the heating operation is shown in FIG. It is divided into three.

  The target low pressure calculator (41) calculates the target low pressure Pls based on the temperature deviation et between the set temperature Ts and the output signal from the room temperature sensor (31) (namely, the room temperature Ta).

  The target high pressure calculator (42) outputs an output signal from the outside air temperature sensor (30) during cooling operation (ie, the outside air temperature T0) and an output signal from the cooling gas cooler outlet temperature sensor (39) (ie, the gas cooler outlet temperature). Based on T4), during the heating operation, the target high pressure Phs is calculated based on the temperature deviation et and an output signal from the heating gas cooler outlet temperature (37) (that is, the gas cooler outlet temperature T4).

  The target discharge temperature calculation unit (43) includes the temperature deviation et, an output signal from the low pressure sensor (32) (ie, the actual low pressure Pl), an output signal from the high pressure sensor (34) (ie, the actual high pressure Ph), A target discharge temperature T1s is calculated based on the operating frequency fc of the compressor (21) and the outside air temperature T0. Specifically, the target discharge temperature calculation unit (43) corresponds to the target superheat degree based on the temperature deviation et, the actual low pressure Pl, the actual high pressure Ph, the operating frequency fc of the compressor (21), and the outside air temperature T0. A target discharge temperature T1s is calculated.

  Each of the target low pressure calculation unit (41), the target high pressure calculation unit (42), and the target discharge temperature calculation unit (43) has a map and a function, and an output value corresponding to each input (target Value).

  The control signal generator (49) is configured to receive different signals for the cooling operation and the heating operation. The control signal generation unit (49) includes a plurality of PID control units (p1a, p2a,..., P1b, p2b,...) Having control parameters corresponding to the input signals.

  During cooling operation, the target low pressure Pls calculated by the target low pressure calculator (41) and the low pressure deviation e1 between the low pressure sensor (32) and the actual low pressure Pl, the target high pressure Phs calculated by the target high pressure calculator (42) and the high pressure sensor (42) 34), the high pressure deviation e2 from the actual high pressure Ph, the target discharge temperature T1s calculated by the target discharge temperature calculation section (43), and the output signal from the discharge temperature sensor (33) (ie, the actual discharge temperature T1). The discharge temperature deviation e3 is input to the control signal generator (49).

  In the cooling operation, nine PID control units (p1a, p2a,...) In the control signal generation unit (49) function. That is, the low-pressure deviation e1 input to the control signal generation unit (49) is input to the three first to third PID control units (p1a, p2a, p3a), and the high-pressure deviation e2 is another three fourth to fourth. The sixth PID control unit (p4a, p5a, p6a) is input, and the discharge temperature deviation e3 is input to another three seventh to ninth PID control units (p7a, p8a, p9a).

  Each of the first to ninth PID control units (p1a, p2a,...) Multiplies the input deviation by a predetermined control parameter and outputs the result. As a result, the control signal generation unit (49) adds the output signals from the first PID control unit (p1a), the fourth PID control unit (p4a), and the seventh PID control unit (p7a) to generate the compressor frequency control signal Δfc. And adding the output signals from the second PID control unit (p2a), the fifth PID control unit (p5a), and the eighth PID control unit (p8a) to generate the expansion valve opening degree control signal Δev, and the third PID control unit ( p3a), the output signals from the sixth PID controller (p6a) and the ninth PID controller (p9a) are added to generate the fan frequency control signal Δff.

  The compressor frequency control signal Δfc, the expansion valve opening control signal Δev, and the fan frequency control signal Δff thus generated are output to the air conditioner (10).

  In the air conditioner (10), the frequency of the alternating current supplied to the motor of the compressor (21) (that is, the operating frequency) is set to a value corresponding to the compressor frequency control signal Δfc, and the compressor (21) The rotation speed changes. As a result, the capacity of the compressor (21) changes according to the compressor frequency control signal Δfc.

  Further, the number of pulses of the signal supplied to the pulse motor of the outdoor expansion valve (24) is set to a value corresponding to the expansion valve opening control signal Δev. As a result, the pulse motor of the outdoor expansion valve (24) rotates by an angle corresponding to the number of pulses, and the valve opening is adjusted according to the expansion valve opening control signal Δev.

  Furthermore, the AC frequency (that is, the operating frequency) supplied to the motor of the outdoor fan (28) is set to a value corresponding to the fan frequency control signal Δff, and the rotational speed of the outdoor fan (28) changes. As a result, the flow rate of air supplied from the outdoor fan (28) to the outdoor heat exchanger (23) changes according to the fan frequency control signal Δff.

  The low pressure Pl, the discharge temperature T1, and the high pressure Ph in the air conditioner (10) operated in such an operating state are supplied to the controller (40 through the low pressure sensor (32), the discharge temperature sensor (33), and the high pressure sensor (34). ). Thus, the controller (40) performs feedback control so that the low pressure Pl (and thus the evaporation temperature), the discharge temperature T1 (and thus the degree of superheat), and the high pressure Ph become target values according to the operating state.

  As described above, each of the compressor frequency control signal Δfc, the expansion valve opening control signal Δev, and the fan frequency control signal Δff is generated by associating the low pressure deviation e1, the high pressure deviation e2, and the discharge temperature deviation e3 with each other. Yes. That is, for example, the compressor (21) controls the low pressure of the refrigeration cycle, the outdoor expansion valve (24) controls the refrigerant discharge temperature, and the outdoor fan (28) controls the high pressure of the refrigeration cycle. , Instead of controlling the control objects individually corresponding to each physical quantity separately, the compressor (21), the outdoor expansion valve (24) and the outdoor fan (28) are controlled together, so that high pressure, low pressure and discharge are controlled. The temperatures are controlled together, i.e. simultaneously. That is, each of the low pressure, the high pressure, and the discharge temperature is not controlled by any one of the compressor (21), the outdoor expansion valve (24), and the outdoor fan (28), but the compressor (21 ), All of the outdoor expansion valve (24) and the outdoor fan (28). More specifically, each of the compressor (21), outdoor expansion valve (24), and outdoor fan (28) to be controlled not only changes in low pressure, high pressure and discharge temperature when only the drive is controlled. , Drive control is performed in consideration of changes in low pressure, high pressure, and discharge temperature when a control target other than the control target is controlled (in other words, the first to ninth steps are taken into consideration). The control parameters of the PID control unit (p1a, p2a,... Are set).

  On the other hand, during heating operation, the high pressure deviation e2 between the target high pressure Phs calculated by the target high pressure calculation unit (42) and the actual high pressure Ph from the high pressure sensor (34), and the target discharge calculated by the target discharge temperature calculation unit (43). A discharge temperature deviation e3 between the temperature T1s and the actual discharge temperature T1 from the discharge temperature sensor (33) is input to the control signal generator (49).

  Further, during the heating operation, the four PID control units (p1b, p2b,...) In the control signal generation unit (49) function. That is, the discharge temperature deviation e3 input to the control signal generation unit (49) is input to the two first and PID control units (p1b, p2b), and the high pressure deviation e2 is the other two third and fourth PID controls. Part (p3b, p4b).

  Each of the first to fourth PID control units (p1b, p2b,...) Multiplies the input deviation by a predetermined control parameter and outputs the result. As a result, the control signal generation unit (49) adds the output signals from the first PID control unit (p1b) and the third PID control unit (p3b) to generate the compressor frequency control signal Δfc, and the second PID control unit ( The expansion valve opening control signal Δev is generated by adding the output signals from p2b) and the fourth PID control unit (p4b).

  The compressor frequency control signal Δfc and the expansion valve opening control signal Δev generated in this way are output to the air conditioner (10).

  In the air conditioner (10), the capacity of the compressor (21) changes in accordance with the compressor frequency control signal Δfc, and the outdoor expansion valve (24) has a valve opening in accordance with the expansion valve opening control signal Δev. Will be adjusted.

  Then, the discharge temperature T1 and the high pressure Ph in the air conditioner (10) operated in such an operating state are fed back to the controller (40) via the discharge temperature sensor (33) and the high pressure sensor (34). Thus, the controller (40) performs feedback control so that the discharge temperature T1 (and thus the degree of superheat) and the high pressure Ph become target values according to the operating state.

  Thus, the compressor frequency control signal Δfc and the expansion valve opening degree control signal Δev are each generated by associating the high pressure deviation e2 and the discharge temperature deviation e3 with each other. In other words, for example, the control target individually corresponding to each physical quantity is separately controlled as in the configuration in which the compressor (21) controls the high pressure of the refrigeration cycle and the outdoor expansion valve (24) controls the refrigerant discharge temperature. Instead of controlling, both the compressor (21) and the outdoor expansion valve (24) are controlled to control both the high pressure and the discharge temperature, that is, simultaneously. That is, each of the high pressure and the discharge temperature is not controlled only by any one of the compressor (21) and the outdoor expansion valve (24), but the compressor (21) and the outdoor expansion valve (24). Controlled by all of the above. More specifically, each of the compressor (21) and the outdoor expansion valve (24) to be controlled is not only a change in high pressure and discharge temperature when only the drive control is performed, but also other control objects other than the control target. Is controlled in consideration of changes in high pressure and discharge temperature when driving is controlled (in other words, the first to fourth PID control units (p1b, p2b,... Control parameters are set).

  Therefore, according to the first embodiment, in addition to a predetermined physical quantity in the air conditioner (10), a plurality of control objects (for example, compressors) are set so that the high pressure of the refrigeration cycle becomes a predetermined target value corresponding to the operating state. (21), the outdoor expansion valve (24), etc.) and simultaneously driving and controlling each controlled object while taking into account changes in the physical quantity and high pressure of the refrigeration cycle when a plurality of controlled objects are controlled. The ability control of the air conditioner (10) (for example, the low pressure and the degree of superheat during cooling operation) can be performed while the high pressure is stably maintained at the target value according to the operating state. As a result, by adjusting one physical quantity, another physical quantity changes, and when the other physical quantity is adjusted to correct the change, another physical quantity or the previously adjusted physical quantity changes. Therefore, it is possible to prevent a situation in which the physical quantity to be controlled does not converge so that further adjustment is required, and to improve the convergence of capacity control and high pressure control in the air conditioner (10). it can.

  In the present embodiment, during the cooling operation, the three physical quantities of low pressure, high pressure, and discharge temperature are controlled by the three control targets of the compressor (21), the outdoor expansion valve (24), and the outdoor fan (28), During heating operation, the two physical quantities of high pressure and discharge temperature are controlled by the two controlled objects, the compressor (21) and the outdoor expansion valve (24). Depending on the controlled object, these physical quantities are likely to be affected. Or there are things that are difficult to give. That is, there is a case where there is a physical quantity that does not change much even if any one control object is changed. In this embodiment, all the physical quantities to be controlled are input and associated with each other to generate a control signal for each control target. However, when generating a control signal for a control target having a physical quantity that is difficult to influence, The relevance of a physical quantity that is less likely to be affected may be reduced or the relevance may be eliminated (specifically, a PID control unit (p1a that generates a control signal for a control target having a physical quantity that is less likely to be affected). ,..., P1b,...), The control parameter of the PID control unit having a physical quantity that does not easily affect this may be reduced or zero).

<< Embodiment 2 of the Invention >>
Next, Embodiment 2 of the present invention will be described.

  The air conditioner (210) according to Embodiment 2 includes two expansion valves (24, 26) between the outdoor heat exchanger (23) and the indoor heat exchanger (27) in the refrigerant circuit (220). In addition, it is different from the air conditioner (10) according to the first embodiment in that two compressors (21a, 21b) are provided and a two-stage compression refrigeration cycle is performed.

  Specifically, as shown in FIG. 4, the air conditioner (210) includes a refrigerant circuit (220) and a controller (240).

  The refrigerant circuit (220) includes a first compressor (21a) on the lower stage side, a second compressor (21b) on the higher stage side, a four-way switching valve (22), and an outdoor heat exchanger (23 ), An outdoor expansion valve (24), a gas-liquid separator (25), an indoor expansion valve (26), and an indoor heat exchanger (27).

  Specifically, in the refrigerant circuit (220), the discharge side of the second compressor (21b) is the first port of the four-way switching valve (22), and the suction side of the first compressor (21a) is the four-way switching valve ( 22) is connected to the second port. The first compressor (21a) and the second compressor (21b) are arranged so that the refrigerant compressed and discharged by the first compressor (21a) is sucked into the second compressor (21b) and further compressed. Connected by piping. In the refrigerant circuit (220), the outdoor heat exchanger (23), the outdoor expansion valve (24), and the gas-liquid separator (25) are sequentially arranged from the third port to the fourth port of the four-way switching valve (22). ), The indoor expansion valve (26) and the indoor heat exchanger (27) are arranged in this order. The gas-liquid separator (25) is connected to a pipe connecting the first compressor (21a) and the second compressor (21b) via the first intermediate pressure refrigerant pipe (25a).

  The first and second compressors (21a, 21b) are the same compressors as in the first embodiment. These first and second compressors (21a, 21b) constitute a compression mechanism.

  Both the outdoor expansion valve (24) and the indoor expansion valve (26) are constituted by variable opening electronic expansion valves whose valve bodies (not shown) are driven by a pulse motor (not shown). The outdoor expansion valve (24) constitutes a first expansion mechanism, and the indoor expansion valve (26) constitutes a second expansion mechanism.

  The gas-liquid separator (25) is a vertically long and cylindrical sealed container. The gas-liquid separator (25) is connected to the outdoor expansion valve (24) and the indoor expansion valve (26) via a bridge circuit (50).

  Specifically, the outdoor expansion valve (24) is connected to one terminal of the bridge circuit (50) via the second intermediate pressure refrigerant pipe (25b). The indoor expansion valve (26) is connected to another terminal of the bridge circuit (50) via the third intermediate pressure refrigerant pipe (25c). Furthermore, one end of the refrigerant inflow pipe (25d) is connected to another terminal of the bridge circuit (50), and the other end of the refrigerant inflow pipe (25d) is connected to the gas-liquid separator (25). It is connected. The other end of the refrigerant inflow pipe (25d) penetrates the upper surface of the closed container of the gas-liquid separator (25) and is located in the upper space. Furthermore, one end of the refrigerant outflow pipe (25e) is connected to another terminal of the bridge circuit (50), and the other end of the refrigerant outflow pipe (25e) is connected to the gas-liquid separator (25). It is connected to the. The other end of the refrigerant outflow pipe (25e) penetrates the upper surface of the sealed container of the gas-liquid separator (25) and is located in the lower space.

  The end portion of the first intermediate pressure refrigerant pipe (25a) on the gas-liquid separator (25) side is located in the upper space through the upper side surface of the sealed container of the gas-liquid separator (25). ing.

  As with the first embodiment, the air conditioner (210) can be switched between a cooling operation and a heating operation by switching the four-way switching valve (22).

  During the cooling operation, the four-way selector valve (22) is set to the first state. When the first and second compressors (21a, 21b) are operated in this state, the outdoor heat exchanger (23) becomes a radiator (gas cooler), and each indoor heat exchanger (27) becomes an evaporator to form a refrigeration cycle. Is done. Specifically, the intermediate pressure refrigerant discharged from the first compressor (21a) is compressed to the supercritical state by the second compressor (21b). The refrigerant in the supercritical state flows to the outdoor heat exchanger (23) and radiates heat to the outdoor air. The radiated high-pressure refrigerant is decompressed by the outdoor expansion valve (24) to become a gas-liquid two-phase intermediate pressure refrigerant, and is connected to the second intermediate pressure refrigerant pipe (25b), the bridge circuit (50), and the refrigerant inflow pipe (25d). Through the gas-liquid separator (25). The intermediate pressure refrigerant flowing into the gas-liquid separator (25) is separated into liquid refrigerant and gas refrigerant. Then, the intermediate-pressure gas refrigerant flows from the upper space of the gas-liquid separator (25) to the suction side of the second compressor (21b) via the first intermediate-pressure refrigerant pipe (25a), and the first compressor ( The intermediate pressure gas refrigerant discharged from 21a) joins and is sucked into the second compressor (21b). On the other hand, the intermediate-pressure liquid refrigerant is temporarily stored in the lower space of the gas-liquid separator (25), and then, from the lower space, the refrigerant outlet pipe (25e), the bridge circuit (50), and the third intermediate-pressure refrigerant pipe. The refrigerant flows out through (25c), further expands (depressurized) in the indoor expansion valve (26), becomes a low-pressure refrigerant in a gas-liquid two-phase state, and flows into the indoor heat exchanger (27). In the indoor heat exchanger (27), the refrigerant absorbs heat from the room air and evaporates, and the cooled room air is supplied to the room. The evaporated refrigerant is sucked into the first compressor (21a) and compressed.

  During the heating operation, the four-way selector valve (22) is set to the second state. When the first and second compressors (21a, 21b) are operated in this state, the indoor heat exchanger (27) becomes a radiator (gas cooler), the outdoor heat exchanger (23) becomes an evaporator, and the refrigeration cycle starts. Done. Specifically, the intermediate-pressure gas refrigerant discharged from the first compressor (21a) is compressed to a supercritical state by the second compressor (21b). The supercritical refrigerant flows into the indoor heat exchanger (27) and radiates heat to the indoor air. Thereby, the heated indoor air is supplied indoors. The radiated refrigerant is decompressed by the indoor expansion valve (26) to become an intermediate-pressure refrigerant in a gas-liquid two-phase state, and passes through the third intermediate-pressure refrigerant pipe (25c), the bridge circuit (50), and the refrigerant inflow pipe (25d). Flow into the gas-liquid separator (25). The intermediate pressure refrigerant flowing into the gas-liquid separator (25) is separated into liquid refrigerant and gas refrigerant. Then, the intermediate-pressure gas refrigerant flows from the upper space of the gas-liquid separator (25) to the suction side of the second compressor (21b) via the first intermediate-pressure refrigerant pipe (25a), and the first compressor ( The intermediate pressure gas refrigerant discharged from 21a) joins and is sucked into the second compressor (21b). On the other hand, after the intermediate-pressure liquid refrigerant is temporarily stored in the lower space of the gas-liquid separator (25), the refrigerant outflow pipe (25e), the bridge circuit (50) and the second intermediate-pressure refrigerant pipe ( Flows into the outdoor expansion valve (24) via 25b). The intermediate-pressure liquid refrigerant is expanded (depressurized) when passing through the outdoor expansion valve (24) to become a low-pressure refrigerant in a gas-liquid two-phase state, and flows into the outdoor heat exchanger (23). In the outdoor heat exchanger (23), the refrigerant absorbs heat from the outdoor air and evaporates. The evaporated refrigerant is sucked into the first compressor (21a) and compressed.

  In the air conditioner (210) configured as described above, the refrigerant circuit (220) includes an indoor temperature sensor (31), a low pressure sensor (32), a discharge temperature sensor (33), and a high pressure sensor (34). ), An intake temperature sensor (35), an intermediate pressure saturation temperature sensor (36), and a heating gas cooler outlet temperature sensor (37).

  The indoor temperature sensor (31) is temperature detection means for detecting the temperature of the indoor air taken into the indoor heat exchanger (27). The low pressure sensor (32) is temperature detection means for detecting the pressure of the refrigerant sucked into the first compressor (21a), that is, the low pressure of the refrigeration cycle in the refrigerant circuit (220). The discharge temperature sensor (33) is temperature detection means for detecting the temperature of the refrigerant discharged from the second compressor (21b). The high pressure sensor (34) is temperature detection means for detecting the pressure of the refrigerant discharged from the second compressor (21b), that is, the high pressure of the refrigeration cycle in the refrigerant circuit (220). The suction temperature sensor (35) is temperature detection means for detecting the temperature of the refrigerant sucked into the first compressor (21a). The intermediate pressure saturation temperature sensor (36) is provided in the refrigerant outflow pipe (25e) connecting the bridge circuit (50) and the gas-liquid separator (25), and the temperature of the intermediate pressure refrigerant, that is, the intermediate pressure of the refrigeration cycle. It is a temperature detection means for detecting the saturation temperature. The heating gas cooler outlet temperature sensor (37) is a temperature detecting means for detecting the outlet refrigerant temperature of the indoor heat exchanger (27) when the refrigerant circulates in the heating cycle in the refrigerant circuit (220).

  The controller (240) includes the indoor temperature sensor (31), the low pressure sensor (32), the high pressure sensor (34), the suction temperature sensor (35), the intermediate pressure saturation temperature sensor (36), and the heating gas cooler outlet temperature sensor ( 37) is input, and the operation frequency of the first and second compressors (21a, 21b) and the opening degree of the outdoor and indoor expansion valves (24, 26) are controlled.

  As shown in FIGS. 5 and 6, the controller (240) includes a target low pressure calculation unit (41) that calculates a target low pressure Pls that is a low pressure target value of the refrigeration cycle, and a target that is a high pressure target value of the refrigeration cycle. A target high pressure calculator (42) for calculating the high pressure Phs, a target superheat degree calculator (44) for calculating a target superheat degree SHs that is a target value of the superheat degree of the refrigerant, and an actual superheat that is the actual superheat degree of the refrigerant An actual superheat degree calculation part (45) for calculating the degree SH, a target intermediate pressure saturation temperature calculation part (46) for calculating a target intermediate pressure saturation temperature T3s that is a target value of the intermediate pressure saturation temperature of the refrigerant, and heating operation A target gas cooler outlet temperature calculating section (47) for calculating a target gas cooler outlet temperature T4s, which is a target value of the refrigerant gas cooler outlet temperature, first and second compressors (21a, 21b), outdoor and indoor expansion valves (24 , 26) Control signal generating unit and a (249). The controller (240) has different control contents between the cooling operation and the heating operation, so the control block diagram during the cooling operation is shown in FIG. 5, and the control block diagram during the heating operation is shown in FIG.

  The target superheat degree calculation unit (44) is based on the temperature deviation et between the set temperature Ts and the room temperature Ta from the room temperature sensor (31) during the cooling operation, and the temperature deviation et and the outside air temperature sensor ( The target superheat degree SHs of the heat exchanger functioning as an evaporator among the outdoor heat exchanger (23) and the indoor heat exchanger (27) is calculated based on the outside air temperature T0 from 30).

  Based on the actual low pressure Pl from the low pressure sensor (32) and the actual suction temperature T2 from the suction temperature sensor (35), the actual superheat degree calculation unit (45) exchanges with the outdoor heat exchanger (23) and the indoor heat exchange. The actual superheat degree SH which is the actual superheat degree of the refrigerant | coolant in the exit of the heat exchanger which functions as an evaporator among evaporators (27) is calculated.

  The target intermediate pressure saturation temperature calculation unit (46) includes an outside air temperature T0 from the outside air temperature sensor (30), an indoor temperature sensor (31), an actual high pressure Ph from the high pressure sensor (34), and a low pressure sensor (32). A target intermediate pressure saturation temperature T3s is calculated based on at least one of the actual low pressure Pl, the target high pressure Phs calculated by the target high pressure calculator (42), and the target low pressure Pls calculated by the target low pressure calculator (41). .

  Based on the temperature deviation et, the target gas cooler outlet temperature calculation unit (47) calculates a target gas cooler outlet temperature T4s that is a target value of the refrigerant temperature at the outlet when the indoor heat exchanger (27) functions as a radiator. Is calculated.

  Each of the target superheat degree calculation unit (44), the actual superheat degree calculation part (45), and the target intermediate pressure saturation temperature calculation part (46) has a map and a function, and corresponds to each input. An output value (target value) is output.

  The control signal generator (249) is configured to receive different signals for the cooling operation and the heating operation. Further, the control signal generation unit (249) includes PID control units (p1c, p2c,..., P1d, p2d,...) Having control parameters corresponding to the input signals.

  During cooling operation, the low pressure deviation e1 between the target low pressure Pls calculated by the target low pressure calculator (41) and the actual low pressure Pl from the low pressure sensor (32), the target high pressure Phs calculated by the target high pressure calculator (42), and the high pressure sensor The superheat degree deviation of the high pressure deviation e2 from the actual high pressure Ph from (34), the target superheat degree SHs calculated by the target superheat degree calculation unit (44) and the actual superheat degree SH calculated by the actual superheat degree calculation unit (45). e4 and the intermediate pressure saturation temperature between the target intermediate pressure saturation temperature T3s calculated by the target intermediate pressure saturation temperature calculation unit (46) and the output signal from the intermediate pressure saturation temperature sensor (36) (that is, the actual intermediate pressure saturation temperature T3). The deviation e5 is input to the control signal generator (249).

  In the cooling operation, 16 PID control units (p1c, p2c,...) In the control signal generation unit (249) function. That is, the high pressure deviation e2 input to the control signal generation unit (249) is input to the four first to fourth PID control units (p1c to p4c), and the intermediate pressure saturation temperature deviation e5 is set to the other four fifths. Thru | or 8th PID control part (p5c-p8c), the low voltage | pressure deviation e1 is inputted into another 4th 9th thru | or 12th PID control part (p9c-p12c), and superheat degree deviation e4 is another 4 pieces. Are input to the thirteenth to sixteenth PID control units (p13c to p16c).

  Each of the first to 16th PID control units (p1c, p2c,...) Multiplies the input deviation by a predetermined control parameter and outputs the result. As a result, the control signal generation unit (249) adds the output signals from the first PID control unit (p1c), the fifth PID control unit (p5c), the ninth PID control unit (p9c), and the thirteenth PID control unit (p13c). The first compressor frequency control signal Δfc1 is generated and the output signals from the second PID control unit (p2c), the sixth PID control unit (p6c), the tenth PID control unit (p10c), and the fourteenth PID control unit (p14c) are added. The second compressor frequency control signal Δfc2 is generated, and output signals from the third PID control unit (p3c), the seventh PID control unit (p7c), the eleventh PID control unit (p11c), and the fifteenth PID control unit (p15c) are generated. Addition to generate the outdoor expansion valve opening control signal Δev1, and output signals from the fourth PID control unit (p4c), the eighth PID control unit (p8c), the twelfth PID control unit (p12c) and the sixteenth PID control unit (p16c) To increase the opening of the indoor tension valve A control signal Δev2 is generated.

  The first compressor frequency control signal Δfc1, the second compressor frequency control signal Δfc2, the outdoor expansion valve opening control signal Δev1 and the indoor expansion valve opening control signal Δev2 generated in this way are output to the air conditioner (210). The

  In the air conditioner (210), the capacity of the first compressor (21a) changes to a value corresponding to the first compressor frequency control signal Δfc1, and the capacity of the second compressor (21b) changes to the second compressor frequency. It changes to a value corresponding to the control signal Δfc2.

  The outdoor expansion valve (24) is adjusted to a valve opening corresponding to the outdoor expansion valve opening control signal Δev1, and the indoor expansion valve (26) is similarly a valve corresponding to the indoor expansion valve opening control signal Δev2. The opening is adjusted.

  The low pressure Pl, high pressure Ph, suction temperature T2, and intermediate pressure saturation temperature T3 in the air conditioner (210) operated in such an operating state are the low pressure sensor (32), the high pressure sensor (34), and the suction temperature sensor (35). And fed back to the controller (240) via the intermediate pressure saturation temperature sensor (36). Thus, the controller (240) performs feedback control so that the low pressure Pl, the high pressure Ph, the superheat degree SH, and the intermediate pressure saturation temperature T3 become target values according to the operating state.

  Thus, the first and second compressor frequency control signals Δfc1 and Δfc2 and the outdoor and indoor expansion valve opening control signals Δev1 and Δev2, respectively, are low pressure deviation e1, high pressure deviation e2, superheat degree deviation e4, and intermediate pressure saturation. The temperature deviation e5 is generated in association with each other. In other words, the control objects individually corresponding to each physical quantity are not controlled separately, but by controlling both the first and second compressors (21a, 21b) and the outdoor and indoor expansion valves (24, 26). , Low pressure, high pressure, superheat and intermediate pressure saturation temperature are controlled together, ie simultaneously. That is, each of the low pressure, the high pressure, the superheat degree, and the intermediate pressure saturation temperature is controlled by any one of the first and second compressors (21a, 21b) and the outdoor and indoor expansion valves (24, 26). Instead, it is controlled by the first and second compressors (21a, 21b) and the outdoor and indoor expansion valves (24, 26). More specifically, each of the first and second compressors (21a, 21b) and the outdoor and indoor expansion valves (24, 26) to be controlled is low pressure, high pressure, and superheat degree when only the drive is controlled. In addition to the change in the intermediate pressure saturation temperature, the drive control is performed in consideration of the change in the low pressure, the high pressure, the superheat degree, and the intermediate pressure saturation temperature when the control target other than itself is controlled (in other words, For example, the control parameters of the first to 16th PID control units (p1c, p2c,...) Are set so that they are taken into consideration).

  On the other hand, during heating operation, the high pressure deviation e2 between the target high pressure Phs calculated by the target high pressure calculator (42) and the actual high pressure Ph from the high pressure sensor (34), and the target superheat degree calculated by the target superheat degree calculator (44). The superheat degree deviation e4 between the SHs and the actual superheat degree SH calculated by the actual superheat degree calculator (45), the target intermediate pressure saturation temperature T3s calculated by the target intermediate pressure saturation temperature calculator (46), and the intermediate pressure saturation temperature sensor ( 36), an intermediate pressure saturation temperature deviation e5 from the actual intermediate pressure saturation temperature T3, a target gas cooler outlet temperature T4s calculated by the target gas cooler outlet temperature calculating section (47), and an output signal from the heating gas cooler outlet temperature sensor (37). The gas cooler outlet temperature deviation e6 (that is, the actual gas cooler outlet temperature T4) is input to the control signal generator (249).

  In the heating operation, the control signal generation unit (249) functions 16 PID control units (p1d, p2d,...) Different from those in the cooling operation. That is, the high pressure deviation e2 input to the control signal generation unit (249) is input to the four first to fourth PID control units (p1d to p4d), and the intermediate pressure saturation temperature deviation e5 is set to the other four fifths. Thru | or 8th PID control part (p5d-p8d), gas cooler exit | outlet temperature deviation e6 is inputted into another four 9th thru | or 12th PID control part (p9d-p12d), and superheat degree deviation e4 is further another. The four thirteenth to sixteenth PID control units (p13d to p16d) are input.

  Each of the first to sixteenth PID control units (p1d, p2d,...) Multiplies the input deviation by a predetermined control parameter and outputs the result. As a result, the control signal generation unit (249) adds the output signals from the first PID control unit (p1d), the fifth PID control unit (p5d), the ninth PID control unit (p9d), and the thirteenth PID control unit (p13d). The first compressor frequency control signal Δfc1 is generated and the output signals from the second PID control unit (p2d), the sixth PID control unit (p6d), the tenth PID control unit (p10d), and the fourteenth PID control unit (p14d) are added. The second compressor frequency control signal Δfc2 is generated, and output signals from the third PID control unit (p3d), the seventh PID control unit (p7d), the eleventh PID control unit (p11d), and the fifteenth PID control unit (p15d) are generated. Addition to generate the outdoor expansion valve opening control signal Δev1, and output signals from the fourth PID control unit (p4d), the eighth PID control unit (p8d), the twelfth PID control unit (p12d) and the sixteenth PID control unit (p16d) To increase the opening of the indoor tension valve A control signal Δev2 is generated.

  The first compressor frequency control signal Δfc1, the second compressor frequency control signal Δfc2, the outdoor expansion valve opening control signal Δev1 and the indoor expansion valve opening control signal Δev2 generated in this way are output to the air conditioner (210). The

  In the air conditioner (210), the capacity of the first compressor (21a) changes according to the first compressor frequency control signal Δfc1, and the capacity of the second compressor (21b) changes to the second compressor frequency control signal. It changes according to Δfc2. Further, the outdoor expansion valve (24) is adjusted to a valve opening corresponding to the outdoor expansion valve opening control signal Δev1, and the indoor expansion valve (26) is adjusted to a valve opening corresponding to the indoor expansion valve opening control signal Δev2. Will come to be.

  The high pressure Ph, the suction temperature T2, the intermediate pressure saturation temperature T3, and the gas cooler outlet temperature T4 in the air conditioner (210) operated in such an operating state are the high pressure sensor (34), the suction temperature sensor (35), and the intermediate pressure saturation. The temperature is fed back to the controller (240) through the temperature sensor (36) and the heating gas cooler outlet temperature sensor (37). In this way, the controller (240) performs feedback control so that the high pressure Ph, the superheat degree SH, the intermediate pressure saturation temperature T3, and the gas cooler outlet temperature T4 become target values according to the operation state.

  Thus, the first and second compressor frequency control signals Δfc1 and Δfc2 and the outdoor and indoor expansion valve opening control signals Δev1 and Δev2, respectively, are a high pressure deviation e2, a superheat degree deviation e4, an intermediate pressure saturation temperature deviation e5, and The gas cooler outlet temperature deviation e6 is generated in association with each other. In other words, the control objects individually corresponding to each physical quantity are not controlled separately, but by controlling both the first and second compressors (21a, 21b) and the outdoor and indoor expansion valves (24, 26). The high pressure, superheat, intermediate pressure saturation temperature and gas cooler outlet temperature are controlled together, i.e. simultaneously. That is, the high pressure, superheat, intermediate pressure saturation temperature, and gas cooler outlet temperature are respectively determined by any one of the first and second compressors (21a, 21b) and the outdoor and indoor expansion valves (24, 26). Rather than being controlled, it is controlled by the first and second compressors (21a, 21b) and all of the outdoor and indoor expansion valves (24, 26). More specifically, each of the first and second compressors (21a, 21b) and the outdoor and indoor expansion valves (24, 26) to be controlled is high pressure, superheat, intermediate when only the drive control is performed. Drive control is performed in consideration of not only changes in pressure saturation temperature and gas cooler outlet temperature, but also changes in high pressure, superheat, intermediate pressure saturation temperature, and gas cooler outlet temperature when other controlled objects are driven and controlled. (In other words, the control parameters of the first to 16th PID control units (p1d, p2d,...) Are set so that they are taken into account).

  Therefore, according to the second embodiment, in addition to the predetermined physical quantity in the air conditioner (210), a plurality of control objects (for example, the first control object) are set so that the high pressure of the refrigeration cycle becomes a predetermined target value corresponding to the operating state. Compressor (21a), outdoor expansion valve (24), etc.) are driven and controlled at the same time, and each controlled object is driven and controlled while taking into account changes in the physical quantity and high pressure of the refrigeration cycle when multiple controlled objects are controlled As a result, it is possible to control the capacity of the air conditioner (210) (for example, the low pressure and the degree of superheat during the cooling operation) while stably maintaining the high pressure at the target value corresponding to the operating state. As a result, by adjusting one physical quantity, another physical quantity changes, and when the other physical quantity is adjusted to correct the change, another physical quantity or the previously adjusted physical quantity changes. As a result, it is possible to prevent a situation in which the physical quantity to be controlled does not converge so that further adjustment is required, and to improve the convergence of the capacity control and the high pressure control in the air conditioner (210). it can.

  In the present embodiment, during the cooling operation, the four physical quantities of low pressure, high pressure, superheat degree, and intermediate pressure saturation temperature are used as the first and second compressors (21a, 21b) and the outdoor and indoor expansion valves (24, 26). In the heating operation, the four physical quantities of high pressure, superheat, intermediate pressure saturation temperature, and gas cooler outlet temperature are used for the first and second compressors (21a, 21b) and the outdoor and indoor expansion valves. Although control is performed with four control targets (24, 26), there are some that are likely to affect each physical quantity, or some that are difficult to give depending on the control target. That is, there is a case where there is a physical quantity that does not change so much even if any one control object is changed. In this embodiment, all the physical quantities to be controlled are input and associated with each other to generate a control signal for each control target. However, when generating a control signal for a control target having a physical quantity that is difficult to influence, The relevance of a physical quantity that is less likely to be affected may be reduced or the relevance may be eliminated (specifically, a PID control unit (p1c that generates a control signal for a control target having a physical quantity that is less likely to be affected). ,..., P1d,...), The control parameter of the PID control unit having a physical quantity that does not easily affect the control parameter may be reduced or zero).

<< Embodiment 3 of the Invention >>
Subsequently, Embodiment 3 of the present invention will be described.

  The air conditioner (310) according to Embodiment 3 is different from the air conditioner (10) according to Embodiment 1 in that a plurality of indoor heat exchangers (27a, 27b) are provided in the refrigerant circuit (320). Different.

  Specifically, as shown in FIG. 7, the air conditioner (310) includes a refrigerant circuit (320) and a controller (340).

  The refrigerant circuit (320) includes a compressor (21), a four-way switching valve (22), an outdoor heat exchanger (23), an outdoor expansion valve (24), a receiver (25), a first The second indoor expansion valve (26a, 26b) and the first and second indoor heat exchangers (27a, 27b) are connected. In this refrigerant circuit (320), a plurality (two in this embodiment) of indoor heat exchangers (27a, 27b) are connected in parallel to each other, and each indoor heat exchanger (27a (27b)) is expanded indoors. A valve (26a (26b)) is connected.

  Specifically, in the refrigerant circuit (320), the compressor (21) has a discharge side connected to a first port of the four-way switching valve (22) and a suction side connected to a second port of the four-way switching valve (22). Has been. Further, in the refrigerant circuit (320), the outdoor heat exchanger (23), the outdoor expansion valve (24), the receiver (25) and 2 are arranged in order from the third port to the fourth port of the four-way switching valve (22). A pair of indoor expansion valves (26a, 26b) and indoor heat exchangers (27a, 27b) are sequentially arranged.

  Both the outdoor expansion valve (24) and the first and second indoor expansion valves (26a, 26b) are constituted by variable opening electronic expansion valves whose valve bodies (not shown) are driven by pulse motors (not shown). Has been. This outdoor expansion valve (24) constitutes a heat source side expansion mechanism, and the first and second indoor expansion valves (26a, 26b) constitute a utilization side expansion mechanism.

  Separate first and second outdoor fans (29a, 29b) are provided in the first and second indoor heat exchangers (27a, 27b), respectively.

  As in the first embodiment, the air conditioner (310) can be switched between a cooling operation and a heating operation by switching the four-way switching valve (22).

  During the cooling operation, the four-way selector valve (22) is set to the first state. When the compressor (21) is operated in this state, the outdoor heat exchanger (23) serves as a radiator and the first and second indoor heat exchangers (27a, 27b) serve as evaporators to perform a refrigeration cycle. Specifically, the supercritical refrigerant discharged from the compressor (21) flows into the outdoor heat exchanger (23) and radiates heat to the outdoor air. The radiated refrigerant expands (depressurizes) when passing through the outdoor expansion valve (24). The expanded refrigerant passes through the receiver (25), then branches and passes through the first and second indoor expansion valves (26a, 26b). At this time, the refrigerant is further expanded (depressurized) and flows to the first and second indoor heat exchangers (27a, 27b). That is, the refrigerant between the outdoor expansion valve (24) including the receiver (25) and the indoor expansion valves (26a, 26b) is in an intermediate pressure state. In the first and second indoor heat exchangers (27a, 27b), the refrigerant absorbs heat from the room air and evaporates, and the cooled room air is supplied to the room. The evaporated refrigerant is sucked into the compressor (21) and compressed.

  During the heating operation, the four-way selector valve (22) is set to the second state. When the compressor (21) is operated in this state, the first and second indoor heat exchangers (27a, 27b) serve as radiators, and the outdoor heat exchanger (23) serves as an evaporator to perform a refrigeration cycle. Specifically, the supercritical refrigerant discharged from the compressor (21) branches and flows to the first and second indoor heat exchangers (27a, 27b) and dissipates heat to the indoor air. Thereby, the heated indoor air is supplied indoors. The radiated refrigerant expands (depressurizes) when passing through the first and second indoor expansion valves (26a, 26b). The expanded refrigerant passes through the receiver (25) and then expands (depressurizes) when passing through the outdoor expansion valve (24). That is, the refrigerant between the outdoor expansion valve (24) including the receiver (25) and the first and second indoor expansion valves (26a, 26b) is in an intermediate pressure state. The refrigerant expanded by the outdoor expansion valve (24) flows into the outdoor heat exchanger (23), absorbs heat from the outdoor air, and evaporates. The evaporated refrigerant is sucked into the compressor (21) and compressed.

  In the air conditioner (310) thus configured, the refrigerant circuit (320) includes the first and second indoor temperature sensors (31a, 31b), the low pressure sensor (32), and the high pressure sensor (34). An intake temperature sensor (35), first and second heating gas cooler outlet temperature sensors (37a, 37b), first and second evaporator outlet temperature sensors (38a, 38b), and a cooling gas cooler outlet temperature. A sensor (39) is provided.

  The first and second indoor temperature sensors (31a, 31b) are temperature detection means for detecting the temperature of the indoor air taken into the first and second indoor heat exchangers (27a, 27b). Two indoor heat exchangers (27a, 27b) are provided. The first and second heating gas cooler outlet temperature sensors (37a, 37b) are connected to the outlets of the first and second indoor heat exchangers (27a, 27b) when the refrigerant circulates in the heating circuit in the refrigerant circuit (320). It is a temperature detection means which each detects refrigerant | coolant temperature, Comprising: It is provided for every 1st and 2nd indoor heat exchanger (27a, 27b). The first and second evaporator outlet temperature sensors (38a, 38b) are used for outlet cooling of the first and second indoor heat exchangers (27a, 27b) when the refrigerant circulates in the cooling cycle in the refrigerant circuit (320). It is a temperature detection means which detects each temperature, Comprising: It is provided for every 1st and 2nd indoor heat exchanger (27a, 27b).

  The controller (340) includes first and second indoor temperature sensors (31a, 31b), a low pressure sensor (32), a high pressure sensor (34), an intake temperature sensor (35), and first and second heating gas cooler outlet temperatures. The output signals of the sensors (37a, 37b) and the first and second evaporator outlet temperature sensors (38a, 38b) are input, the operating frequency of the compressor (21), the outdoor, first and second indoor expansion valves (24 , 26a, 26b).

  As shown in FIGS. 8 and 9, the controller (340) includes a target low pressure calculation unit (41) that calculates a target low pressure Pls that is a low pressure target value of the refrigeration cycle, and a target that is a high pressure target value of the refrigeration cycle. A target high pressure calculation unit (42) for calculating the high pressure Phs, an actual superheat calculation unit (45) for calculating the actual superheat degree SH which is the actual superheat degree of the refrigerant, and a first indoor heat exchanger ( A target first superheat degree calculation unit (44a) for calculating a target first superheat degree SHas that is a target value of the superheat degree of the refrigerant at the outlet of 27a), and an outlet of the second indoor heat exchanger (27b) during cooling operation A target second superheat degree calculation unit (44b) that calculates a target second superheat degree SHbs that is a target value of the superheat degree of the refrigerant in the refrigerant, and a refrigerant gas cooler at the outlet of the first indoor heat exchanger (27a) during heating operation Target first gas cooler outlet temperature T4a which is a target value of outlet temperature A target first gas cooler outlet temperature calculating section (47a) for calculating the target gas gas outlet temperature T4bs, which is a target value of the refrigerant gas cooler outlet temperature at the outlet of the second indoor heat exchanger (27b) during heating operation. A target second gas cooler outlet temperature calculation unit (47b) to be calculated, and a target superheat degree calculation unit to calculate a target superheat degree SHs that is a target value of the superheat degree of the refrigerant at the outlet of the outdoor heat exchanger (23) during heating operation (44), and a compressor (21) and a control signal generator (349) for generating control signals to the outdoor, first indoor and second indoor expansion valves (24, 26a, 26b). Since the controller (340) has different control contents between the cooling operation and the heating operation, the control block diagram during the cooling operation is shown in FIG. 8, and the control block diagram during the heating operation is shown in FIG.

  The target low-pressure calculating unit (41) is configured to generate a temperature deviation eta between the set temperature Tsa on the first indoor heat exchanger (27a) side and the indoor temperature Taa from the first indoor temperature sensor (31a), and a second indoor heat exchange. Based on the temperature deviation etb between the set temperature Tsb on the container (27b) side and the room temperature Tab from the second room temperature sensor (31b), the target low pressure Pls of the air conditioner (310) as a whole is calculated.

  The target high pressure calculator (42) is configured to use the first indoor temperature during heating operation based on the outside air temperature T0 from the outside air temperature sensor (30) during cooling operation and the gas cooler outlet temperature T4 from the gas cooler outlet temperature sensor (39) during cooling. The temperature deviation eta on the heat exchanger (27a) side, the temperature deviation etb on the second indoor heat exchanger (27b) side, the target first gas cooler outlet temperature T4as calculated by the target first gas cooler outlet temperature calculator (47a), The target second gas cooler outlet temperature T4bs calculated by the target second gas cooler outlet temperature calculation section (47b) and the first and second gas cooler outlet temperatures T4a from the first and second heating gas cooler outlet temperature sensors (37a, 37b). , T4b, the target high pressure Phs of the air conditioner (310) as a whole is calculated.

  The target first superheat degree calculation unit (44a) calculates a target first superheat degree SHas based on the temperature deviation eta on the first indoor heat exchanger (27a) side.

  The target second superheat degree calculation unit (44b) calculates a target second superheat degree SHbs based on the temperature deviation etb on the second indoor heat exchanger (27b) side.

  In the cooling operation, the actual superheat degree calculation unit (45) includes the actual low pressure Pl from the low pressure sensor (32) and the first or second evaporator from the first or second evaporator outlet temperature sensor (38a, 38b). While calculating the actual first or second superheat degree SHa, SHb, which is the actual superheat degree of the refrigerant at the outlet of the first or second indoor heat exchanger (27a, 27b) based on the outlet temperature T5a, T5b, During the heating operation, the actual superheat degree of the refrigerant at the outlet of the outdoor heat exchanger (23) based on the actual low pressure Pl from the low pressure sensor (32) and the actual suction temperature T2 from the suction temperature sensor (35). The superheat degree SH is calculated.

  The target first gas cooler outlet temperature calculator (47a) calculates a target first gas cooler outlet temperature T4as based on the temperature deviation eta on the first indoor heat exchanger (27a) side.

  The target second gas cooler outlet temperature calculator (47b) calculates a target second gas cooler outlet temperature T4bs based on the temperature deviation etb on the second indoor heat exchanger (27b) side.

  These target low pressure calculator (41), target high pressure calculator (42), target first superheat degree calculator (44a), target second superheat degree calculator (44b), target superheat degree calculator (44), target Each of the first gas cooler outlet temperature calculator (47a) and the target second gas cooler outlet temperature calculator (47b) has a map and a function, and is configured to output a corresponding output value for each input. Has been.

  The control signal generator (349) is configured to receive different signals for the cooling operation and the heating operation. The control signal generation unit (349) includes PID control units (p1e, p2e,..., P1f, p2f,...) Having control parameters corresponding to the input signals.

  During cooling operation, the low pressure deviation e1 between the target low pressure Pls calculated by the target low pressure calculator (41) and the actual low pressure Pl from the low pressure sensor (32), the target high pressure Phs calculated by the target high pressure calculator (42), and the high pressure sensor The high pressure deviation e2 from the actual high pressure Ph from (34), the target superheat degree SHas calculated by the target first superheat degree calculation unit (44a), and the first indoor heat exchanger (45) calculated by the actual superheat degree calculation unit (45) ( 27a) the first superheat degree deviation e4a with the actual first superheat degree SHa and the target superheat degree SHbs calculated by the target second superheat degree calculation unit (44b) and the second value calculated by the actual superheat degree calculation unit (45). A second superheat degree deviation e4b from the actual second superheat degree SHb on the indoor heat exchanger (27b) side is input to the control signal generation unit (349).

  In the cooling operation, 16 PID control units (p1e, p2e,...) In the control signal generation unit (349) function. That is, the low pressure deviation e1 input to the control signal generation unit (349) is input to the four first to fourth PID control units (p1e to p4e), and the high pressure deviation e2 is set to the other four fifth to eighth PIDs. The first superheat degree deviation e4a is inputted to another four ninth to twelfth PID control parts (p9e to p12e), and the second superheat degree deviation e4b is further inputted to the control part (p5e to p8e). The four thirteenth to sixteenth PID control units (p13e to p16e) are input.

  Each of the first to sixteenth PID control units (p1e, p2e,...) Multiplies the input deviation by a predetermined control parameter and outputs the result. Specifically, the control signal generation unit (349) adds the output signals from the first PID control unit (p1e), the fifth PID control unit (p5e), the ninth PID control unit (p9e), and the thirteenth PID control unit (p13e). The compressor frequency control signal Δfc is generated, and output signals from the second PID control unit (p2e), the sixth PID control unit (p6e), the tenth PID control unit (p10e), and the fourteenth PID control unit (p14e) are added. An outdoor expansion valve opening control signal Δev1 is generated, and output signals from the third PID control unit (p3e), the seventh PID control unit (p7e), the eleventh PID control unit (p11e), and the fifteenth PID control unit (p15e) are added. The first indoor expansion valve opening control signal Δev2a is generated and output signals from the fourth PID control unit (p4e), the eighth PID control unit (p8e), the twelfth PID control unit (p12e), and the sixteenth PID control unit (p16e). Is added to open the second indoor tension valve It generates a control signal Derutaev2b.

  The compressor frequency control signal Δfc, the outdoor expansion valve opening control signal Δev1, the first indoor expansion valve opening control signal Δev2a, and the second indoor expansion valve opening control signal Δev2b generated in this way are sent to the air conditioner (310). Is output.

  In the air conditioner (310), the capacity of the compressor (21) changes to a value corresponding to the compressor frequency control signal Δfc.

  The outdoor expansion valve (24) is adjusted to a valve opening corresponding to the outdoor expansion valve opening control signal Δev1, and the first indoor expansion valve (26a) is adjusted according to the first indoor expansion valve opening control signal Δev2a. The second indoor expansion valve (26b) is adjusted to a valve opening corresponding to the second indoor expansion valve opening control signal Δev2b.

  And in the air conditioner (310) operated in such an operating state, the low pressure Pl, the high pressure Ph, the first evaporator outlet temperature T5a on the first indoor heat exchanger (27a) side, and the second indoor heat exchanger (27b) The second evaporator outlet temperature T5b on the side is fed back to the controller (340) via the low pressure sensor (32), the high pressure sensor (34), and the first and second evaporator outlet temperature sensors (38a, 38b). Thus, the controller (340) performs feedback control so that the low pressure Pl, the high pressure Ph, and the first and second superheat degrees SHa and SHb become target values according to the operating state.

  Thus, the compressor frequency control signal Δfc and the outdoor, first indoor and second indoor expansion valve opening control signals Δev1, Δev2a, Δev2b are respectively low pressure deviation e1, high pressure deviation e2, first superheat degree deviation e4a and The second superheat degree deviation e4b is generated in association with each other. In other words, the control target corresponding to each physical quantity is not controlled separately, but the compressor (21), the outdoor expansion valve (24), and the first and second indoor expansion valves (26a, 26b) are controlled together. Thus, the low pressure, the high pressure, the first superheat degree and the second superheat degree are controlled together, that is, simultaneously. That is, each of the low pressure, the high pressure, the first superheat degree, and the second superheat degree is any of the compressor (21), the outdoor expansion valve (24), and the first and second indoor expansion valves (26a, 26b). Instead of being controlled by one, it is controlled by the compressor (21), the outdoor expansion valve (24), and the first and second indoor expansion valves (26a, 26b). More specifically, each of the compressor (21), the outdoor expansion valve (24), and the first and second indoor expansion valves (26a, 26b) to be controlled is low pressure and high pressure when only the drive is controlled. Considering not only changes in the first superheat degree and the second superheat degree, but also changes in the low pressure, high pressure, first superheat degree, and second superheat degree when other controlled objects are driven and controlled. Drive control is performed (in other words, the control parameters of the first to 16th PID control units (p1e, p2e,...) Are set so that they are taken into consideration).

  On the other hand, during heating operation, the high pressure deviation e2 between the target high pressure Phs calculated by the target high pressure calculator (42) and the actual high pressure Ph from the high pressure sensor (34), and the target superheat degree calculated by the target superheat degree calculator (44). Supersaturation deviation e4 between SHs and actual superheat degree SH calculated by actual superheat degree calculator (45), target first gas cooler outlet temperature T4as calculated by target first gas cooler outlet temperature calculator (47a), and first heating time The first gas cooler outlet temperature deviation e6a from the actual first gas cooler outlet temperature T4a from the gas cooler outlet temperature sensor (37a), the target second gas cooler outlet temperature T4bs calculated by the target second gas cooler outlet temperature calculator (47b), and the second The second gas cooler outlet temperature deviation e6b from the actual second gas cooler outlet temperature T4b from the heating gas cooler outlet temperature sensor (37b) is input to the control signal generator (349).

  Further, during the heating operation, the control signal generation unit (349) functions 16 PID control units (p1f, p2f,...) Different from those during the cooling operation. That is, the high pressure deviation e2 input to the control signal generation unit (349) is input to the four first to fourth PID control units (p1f to p4f), and the first gas cooler outlet temperature deviation e6a is set to another four. The second gas cooler outlet temperature deviation e6b is inputted to another four ninth to twelfth PID control parts (p9f to p12f), and the superheat degree deviation e4 is inputted to the fifth to eighth PID control parts (p5f to p8f). Are input to four other thirteenth to sixteenth PID control units (p13f to p16f).

  Each of the first to 16th PID control units (p1f, p2f,...) Multiplies the input deviation by a predetermined control parameter and outputs the result. Specifically, the control signal generation unit (349) adds the output signals from the first PID control unit (p1f), the fifth PID control unit (p5f), the ninth PID control unit (p9f), and the thirteenth PID control unit (p13f). The compressor frequency control signal Δfc is generated and the output signals from the second PID control unit (p2e), the sixth PID control unit (p6e), the tenth PID control unit (p10e), and the fourteenth PID control unit (p14e) are added. An outdoor expansion valve opening control signal Δev1 is generated, and output signals from the third PID control unit (p3e), the seventh PID control unit (p7e), the eleventh PID control unit (p11e), and the fifteenth PID control unit (p15e) are added. The first indoor expansion valve opening control signal Δev2a is generated and output signals from the fourth PID control unit (p4e), the eighth PID control unit (p8e), the twelfth PID control unit (p12e), and the sixteenth PID control unit (p16e). Is added to open the second indoor tension valve Degree control signal Δev2b is generated.

  The compressor frequency control signal Δfc, the outdoor expansion valve opening control signal Δev1, the first indoor expansion valve opening control signal Δev2a, and the second indoor expansion valve opening control signal Δev2b generated in this way are sent to the air conditioner (310). Is output.

  In the air conditioner (310), the capacity of the compressor (21) changes to a value corresponding to the compressor frequency control signal Δfc.

  The outdoor expansion valve (24) is adjusted to a valve opening corresponding to the outdoor expansion valve opening control signal Δev1, and the first indoor expansion valve (26a) is a valve corresponding to the first indoor expansion valve opening control signal Δev2a. The second indoor expansion valve (26b) is adjusted to the valve opening according to the second indoor expansion valve opening control signal Δev2b.

  And in the air conditioner (310) operated in such an operating state, the low pressure Pl, the high pressure Ph, the first gas cooler outlet temperature T4a on the first indoor heat exchanger (27a) side, and the second indoor heat exchanger (27b) side The second gas cooler outlet temperature T4b is fed back to the controller (340) via the low pressure sensor (32), the high pressure sensor (34), and the first and second heating gas cooler outlet temperature sensors (37a, 37b). Thus, the controller (340) performs feedback control so that the low pressure Pl, the high pressure Ph, and the first and second superheat degrees SHa and SHb become target values according to the operating state.

  Thus, the compressor frequency control signal Δfc and the outdoor, first indoor and second indoor expansion valve opening control signals Δev1, Δev2a, Δev2b are respectively a high pressure deviation e2, a superheat degree deviation e4, and a first gas cooler outlet temperature deviation. e6a and the second gas cooler outlet temperature deviation e6b are generated in association with each other. In other words, the control target corresponding to each physical quantity is not controlled separately, but the compressor (21), the outdoor expansion valve (24), and the first and second indoor expansion valves (26a, 26b) are controlled together. Thus, the high pressure, the degree of superheat, the first gas cooler outlet temperature, and the second gas cooler outlet temperature are all controlled, that is, simultaneously. That is, the high pressure, the degree of superheat, the first gas cooler outlet temperature, and the second gas cooler outlet temperature are respectively the compressor (21), the outdoor expansion valve (24), and the first and second indoor expansion valves (26a, 26b). It is not controlled by any one of these, but is controlled by all of the compressor (21), the outdoor expansion valve (24), and the first and second indoor expansion valves (26a, 26b). More specifically, the compressor (21), the outdoor expansion valve (24), and the first and second indoor expansion valves (26a, 26b) to be controlled are high pressure and overheat when only the drive is controlled. Not only changes in the first gas cooler outlet temperature and the second gas cooler outlet temperature, but also changes in high pressure, superheat, first gas cooler outlet temperature, and second gas cooler outlet temperature when a control object other than itself is driven and controlled. (In other words, the control parameters of the first to 16th PID control units (p1f, p2f,...) Are set so that they are taken into consideration).

  Therefore, according to the third embodiment, in addition to a predetermined physical quantity in the air conditioner (310), a plurality of control objects (for example, compressors) are set so that the high pressure of the refrigeration cycle becomes a predetermined target value corresponding to the operating state. (21), the outdoor expansion valve (24), etc.) and simultaneously driving and controlling each controlled object while taking into account changes in the physical quantity and high pressure of the refrigeration cycle when a plurality of controlled objects are controlled. The capacity control of the air conditioner (310) (for example, the low pressure and the degree of superheat during the cooling operation) can be performed while the high pressure is stably maintained at the target value according to the operation state. As a result, by adjusting one physical quantity, another physical quantity changes, and when the other physical quantity is adjusted to correct the change, another physical quantity or the previously adjusted physical quantity changes. As a result, it is possible to prevent a situation in which the physical quantity to be controlled does not converge so that further adjustment is required, and to improve the convergence of capacity control and high pressure control in the air conditioner (310). it can.

  In the present embodiment, during the cooling operation, four physical quantities of low pressure, high pressure, first superheat degree, and second superheat degree are used as the compressor (21), the outdoor expansion valve (24), and the first and second indoor expansion valves. (26a, 26b) and the four physical quantities of high pressure, first gas cooler outlet temperature, second gas cooler outlet temperature and superheat degree during the heating operation, the compressor (21), outdoor expansion valve ( 24) and the first and second indoor expansion valves (26a, 26b) are controlled by four controlled objects. Depending on the controlled objects, there are those that easily or hardly affect each physical quantity. That is, there is a case where there is a physical quantity that does not change so much even if any one control object is changed. In this embodiment, all the physical quantities to be controlled are input and associated with each other to generate a control signal for each control target. However, when generating a control signal for a control target having a physical quantity that is difficult to influence, The relevance of a physical quantity that is less likely to be affected may be reduced or the relevance may be eliminated (specifically, a PID control unit (p1e that generates a control signal for a control target having a physical quantity that is less likely to be affected). ,..., P1f,...), The control parameter of the PID control unit having a physical quantity that does not easily affect this may be reduced or zero).

<< Other Embodiments >>
The present invention may be configured as follows with respect to the embodiment.

  That is, the present invention is not limited to the refrigerant circuit according to the embodiment, and can be adopted in any refrigerant circuit. For example, as shown in FIG. 10, it may be a multi-type air conditioner (410) that performs a two-stage compression refrigeration cycle and is provided with a plurality of indoor units. In this case, for example, the high pressure, the low pressure, the first evaporator outlet temperature, the second evaporator outlet temperature, and the intermediate pressure saturation temperature are input, and the first and second compressors (21a, 21b) are associated with these physical quantities. ), Control signals for driving and controlling the first and second indoor expansion valves (26a, 26b) and the outdoor expansion valve (24) may be generated. As a result, when all of the first and second compressors (21a, 21b), the first and second indoor expansion valves (26a, 26b), and the outdoor expansion valve (24) are adjusted, the high pressure, low pressure, The first and second compressors (21a, 21b), the first and second indoor expansion valves are set so that the one evaporator outlet temperature, the second evaporator outlet temperature, and the intermediate pressure saturation temperature each have a predetermined target value. (26a, 26b) and the outdoor expansion valve (24) control signals are generated, that is, the first and second compressors (21a, 21b), the first and second indoor expansion valves (26a, 26b), and The outdoor expansion valve (24) is driven and controlled.

  For example, as shown in FIG. 11, a two-stage compression refrigeration cycle in which an internal heat exchanger (51) is provided between the outdoor heat exchanger (23) and the outdoor expansion valve (24) is performed and the indoor unit A multi-type air conditioner (510) in which a plurality of air conditioners are provided.

  Specifically, in the air conditioner (510), the first compressor (21a) and the second compressor branch from the middle of the connection pipe (52) connecting the outdoor heat exchanger (23) and the receiver (25). A bypass pipe (53) connected to the pipe connecting the compressor (21b) is provided. A bypass-side expansion valve (54) is provided in the middle of the bypass pipe (53), and the refrigerant flowing through the bypass pipe (53) is depressurized by the bypass-side expansion valve (54) to be an intermediate pressure refrigerant. Become.

  In addition, an outdoor expansion valve (24) is provided in a portion of the connection pipe (52) that is closer to the receiver (25) than the branch of the bypass pipe (53).

  The internal heat exchanger (51) includes a connection pipe (52) between the branch pipe (53) and the outdoor expansion valve (24), and a bypass pipe (53) on the bypass side. It is provided across the portion downstream of the expansion valve (54), and heat exchange is performed between the refrigerants flowing through both portions. That is, during cooling operation, the refrigerant flowing through the bypass pipe (53) is reduced in pressure by the bypass side expansion valve (54) to become an intermediate-pressure liquid refrigerant or a gas-liquid two-phase refrigerant, and then the internal heat exchanger ( By circulating through 51), it absorbs heat from the refrigerant flowing through the connecting pipe (52) and becomes a superheated gas refrigerant and flows to the suction side of the second compressor (21b). On the other hand, the refrigerant flowing through the connection pipe (52) flows out of the outdoor heat exchanger (23) and then dissipates heat to the refrigerant flowing through the bypass pipe (53) by flowing through the internal heat exchanger (51). After being in a supercooled state, the pressure is reduced by the outdoor expansion valve (24) to become an intermediate pressure and flows into the receiver (25).

  A receiver pressure saturation temperature sensor (55) is provided in a portion of the connection pipe (52) closer to the receiver (25) than the outdoor expander (24). Further, an intermediate pressure saturation temperature sensor (36) is provided in a portion of the bypass pipe (53) on the downstream side of the internal heat exchanger (51).

  In the air conditioner (510) configured as described above, for example, detection is performed by a high pressure, a low pressure, a first evaporator outlet temperature, a second evaporator outlet temperature, an intermediate pressure saturation temperature, and a receiver pressure saturation temperature sensor (55). The receiver internal pressure is input, and the plurality of physical quantities are related to each other so that the first and second compressors (21a, 21b), the first and second indoor expansion valves (26a, 26b), the outdoor expansion valve (24), and A control signal for driving and controlling each of the bypass side expansion valves (54) is generated. As a result, all of the first and second compressors (21a, 21b), the first and second indoor expansion valves (26a, 26b), the outdoor expansion valve (24), and the bypass side expansion valve (54) were adjusted. In this case, the first and second compressors (21a, 21a, 21) are set so that the high pressure, the low pressure, the first evaporator outlet temperature, the second evaporator outlet temperature, the intermediate pressure saturation temperature, and the receiver internal pressure become predetermined target values. 21b), control signals for the first and second indoor expansion valves (26a, 26b), the outdoor expansion valve (24) and the bypass side expansion valve (54) are generated, that is, the first and second compressors ( 21a, 21b), the first and second indoor expansion valves (26a, 26b), the outdoor expansion valve (24), and the bypass side expansion valve (54) are driven and controlled.

  Further, in the second embodiment, two compressors (21a, 21b) and two expansion valves (24, 26) are provided to perform a two-stage compression refrigeration cycle. A configuration may be employed in which gas injection is provided during the compression process of the compressor. In this case, since a total of three objects to be controlled are one compressor and two expansion valves (24, 26), it is preferable to control a total of three physical quantities (including at least the high pressure of the refrigeration cycle). .

  In the embodiment, a control signal for one control object is generated by adding a plurality of physical quantities as inputs and multiplying each physical quantity by a control parameter. However, the present invention is not limited to this. It is not a thing. For example, based on a dynamic model of the refrigeration cycle of each refrigerant circuit, it is configured to calculate a plurality of control signals as outputs by taking a plurality of physical quantities as inputs and multiplying this by a matrix of control parameters. Also good. Even in such a configuration, it is possible to generate a control signal to be controlled by associating inputs of a plurality of physical quantities with each other, and to control a plurality of physical quantities together by controlling the plurality of control targets together. And the convergence of each physical quantity can be improved.

  Furthermore, in the said embodiment, although the expansion valve is employ | adopted as an expansion mechanism, it is not restricted to this, An expander may be sufficient.

  Furthermore, only in Embodiment 1, the outdoor fan (28) is controlled as a control target. However, in other embodiments, the outdoor fan (28) is also used for high pressure control and capacity control. Good.

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for a refrigeration apparatus including a refrigerant circuit that performs a supercritical cycle.

1 is a piping system diagram illustrating a configuration of an air conditioner according to Embodiment 1. FIG. It is a control block diagram of a controller at the time of cooling operation. It is a control block diagram of a controller at the time of heating operation. It is a piping system diagram which shows the structure of the air conditioning apparatus which concerns on Embodiment 2. It is a control block diagram of a controller at the time of cooling operation. It is a control block diagram of a controller at the time of heating operation. It is a piping system diagram which shows the structure of the air conditioning apparatus which concerns on Embodiment 3. It is a control block diagram of a controller at the time of cooling operation. It is a control block diagram of a controller at the time of heating operation. It is a piping system diagram which shows the structure of the air conditioning apparatus which concerns on other embodiment. It is a piping system diagram which shows the structure of the air conditioning apparatus which concerns on another other embodiment.

Explanation of symbols

20 Refrigerant circuit
21 Compressor (compression mechanism)
21a First compressor (compression mechanism)
21b Second compressor (compression mechanism)
23 Outdoor heat exchanger (heat source side heat exchanger)
24 Outdoor expansion valve (expansion mechanism, first expansion mechanism, heat source side expansion mechanism)
26 Indoor expansion valve (expansion mechanism, second expansion mechanism)
26a 1st indoor expansion valve (use side expansion mechanism)
26b Second indoor expansion valve (use side expansion mechanism)
27 Indoor heat exchanger (use side heat exchanger)
27a 1st indoor heat exchanger (use side heat exchanger)
27b 2nd indoor heat exchanger (use side heat exchanger)
28 Outdoor fan (heat source side fan)
40,240,340 Controller (control means)

Claims (8)

A compression mechanism (21), a heat source side heat exchanger (23), an expansion mechanism (24), and a use side heat exchanger (27) are connected in order to perform a supercritical refrigeration cycle in which the high pressure exceeds the critical pressure of the refrigerant. A refrigeration apparatus comprising a refrigerant circuit (20) and control means (40) for controlling a control object including at least the compression mechanism (21) and the expansion mechanism (24),
The said control means (40) controls both the predetermined physical quantity used as the parameter | index of the capacity | capacitance of a refrigerating device, and the high voltage | pressure of a refrigerating cycle by controlling the said several control object together. In claim 1,
The control means (40) receives the predetermined physical quantity and the high pressure of the refrigeration cycle as inputs, generates a control signal for each of the plurality of control objects in association with the physical quantity and the high pressure, and generates the control signal. The refrigeration apparatus is characterized in that both the predetermined physical quantity and the high pressure of the refrigeration cycle are controlled by outputting to each control object. In claim 1 or 2,
A heat source side fan (28) for supplying air to the heat source side heat exchanger (23) for exchanging heat between the refrigerant and air;
During cooling operation,
The predetermined physical quantity is a refrigerant evaporation temperature in the use side heat exchanger (27) and a superheat degree of the refrigerant at an outlet of the use side heat exchanger (27),
The control object further includes the heat source side fan (28),
The control means (40) controls both the compression mechanism (21), the expansion mechanism (24), and the heat source side fan (28) with the evaporation temperature and superheat degree of the refrigerant and the high pressure of the refrigeration cycle as inputs. Thus, both the evaporating temperature of the refrigerant, the superheat degree of the refrigerant, and the high pressure of the refrigeration cycle are controlled. In claim 1 or 2,
During heating operation,
The predetermined physical quantity is the degree of superheat of the refrigerant at the outlet of the heat source side heat exchanger (23),
The control means (40) receives the superheat degree of the refrigerant and the high pressure of the refrigeration cycle as inputs, and controls both the compression mechanism (21) and the expansion mechanism (24), whereby the superheat degree of the refrigerant and the refrigeration cycle are controlled. The refrigeration apparatus characterized by controlling both the high pressure of the two. In claim 1 or 2,
The compression mechanism includes a first compressor (21a) that sucks and compresses a low-pressure refrigerant, and a second compressor (21b) that further compresses and discharges the refrigerant discharged from the first compressor (21a). And
The expansion mechanism includes a first expansion mechanism (24) that expands a high-pressure refrigerant and a second expansion mechanism (26) that further expands the refrigerant that has reached an intermediate pressure by the first expansion mechanism (24). ,
During cooling operation,
The predetermined physical quantities are a refrigerant evaporation temperature in the use side heat exchanger (27), a superheat degree of the refrigerant at an outlet of the use side heat exchanger (27), and an intermediate pressure of the refrigeration cycle,
The control means (240) receives the first and second compressors (21a, 21b) and the first as input with the evaporating temperature of the refrigerant, the degree of superheat of the refrigerant, the intermediate pressure of the refrigeration cycle and the high pressure of the refrigeration cycle as inputs. By controlling both the first and second expansion mechanisms (24, 26), the evaporating temperature of the refrigerant, the superheat degree of the refrigerant, the intermediate pressure of the refrigeration cycle, and the high pressure of the refrigeration cycle are both controlled. Refrigeration equipment. In claim 1 or 2,
The compression mechanism includes a first compressor (21a) that sucks and compresses a low-pressure refrigerant, and a second compressor (21b) that further compresses and discharges the refrigerant discharged from the first compressor (21a). And
The expansion mechanism includes a first expansion mechanism (24) that expands a high-pressure refrigerant and a second expansion mechanism (26) that further expands the refrigerant that has reached an intermediate pressure by the first expansion mechanism (24). ,
During heating operation,
The predetermined physical quantity includes the refrigerant evaporation temperature in the heat source side heat exchanger (23), the degree of superheat of the refrigerant at the outlet of the heat source side heat exchanger (23), and the outlet of the use side heat exchanger (27). Gas cooler outlet temperature, which is the temperature of the refrigerant,
The control means (240) receives the first and second compressors (21a, 21b) and the refrigerant temperature, the superheat degree of the refrigerant, the gas cooler outlet temperature of the refrigerant, and the high pressure of the refrigeration cycle as inputs. By controlling both the first and second expansion mechanisms (24, 26), the evaporation temperature of the refrigerant, the degree of superheat of the refrigerant, the gas cooler outlet temperature of the refrigerant, and the high pressure of the refrigeration cycle are controlled together. Refrigeration equipment. In claim 1 or 2,
The use side heat exchangers (27a, 27b) are provided in plural and connected in parallel to each other,
The expansion mechanism includes a plurality of utilization side expansion mechanisms (26a, 26b) provided corresponding to the respective utilization side heat exchangers (27a, 27b), the utilization side heat exchangers (27a, 27b), and A heat source side expansion mechanism (24) provided between the use side expansion mechanism (26a, 26b) and the heat source side heat exchanger (23);
During cooling operation,
The predetermined physical quantity is a refrigerant evaporation temperature in the use side heat exchanger (27a, 27b) and a superheat degree of the refrigerant at an outlet of each use side heat exchanger (27a, 27b),
The control means (340) receives the evaporating temperature of the refrigerant, the superheat degree of the refrigerant in each of the use side heat exchangers (27a, 27b), and the high pressure of the refrigeration cycle as inputs. By controlling both the use side expansion mechanism (26a, 26b) and the heat source side expansion mechanism (24) of the refrigerant, the evaporating temperature of the refrigerant and the overheating of the refrigerant in each of the use side heat exchangers (27a, 27b) A refrigeration system that controls both the temperature and the high pressure of the refrigeration cycle. In claim 1 or 2,
The use side heat exchangers (27a, 27b) are provided in plural and connected in parallel to each other,
The expansion mechanism includes a plurality of utilization side expansion mechanisms (26a, 26b) provided corresponding to the respective utilization side heat exchangers (27a, 27b), the utilization side heat exchangers (27a, 27b), and A heat source side expansion mechanism (24) provided between the use side expansion mechanism (26a, 26b) and the heat source side heat exchanger (23);
During heating operation,
The predetermined physical quantity is a degree of superheat of the refrigerant at the outlet of the heat source side heat exchanger (23) and a gas cooler outlet temperature which is a temperature of the refrigerant at the outlet of each use side heat exchanger (27a, 27b),
The control means (340) receives the superheat degree of the refrigerant, the gas cooler outlet temperature of the refrigerant in each of the use side heat exchangers (27a, 27b), and the high pressure of the refrigeration cycle as inputs, the compression mechanism (21), By controlling both the plurality of use side expansion mechanisms (26a, 26b) and the heat source side expansion mechanism (24), the degree of superheat of the refrigerant and the refrigerant in each use side heat exchanger (27a, 27b) are controlled. A refrigeration apparatus that controls both the gas cooler outlet temperature and the high pressure of the refrigeration cycle.

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