JPH08152208A - Refrigerant-circulating system, and refrigerating and air-conditioner apparatus - Google Patents

Abstract

PURPOSE: To obtain a circulating system wherein the composition of a nonazeotropic mixture refrigerant is maintained so as to be suitable for its operating condition at all times, reliability is high and its capacity can be displayed, by a method wherein the composition of the mixed refrigerant circulating in a refrigerant circuit is estimated at the time of operation, is varied according to its estimate, and is properly controlled corresponding to the operating condition. CONSTITUTION: A compressor 1, a four-way valve 2, a heat source-side heat-exchanger 3, a throttling device 4, a load-side heat-exchanger 5 and a low-pressure receiver 6 are respectively connected to each other, and a refrigerant circuit is composed. A controller 100 determines the degree of opening of the throttling device 4 on the basis of data from a first thermal sensor 101, a second temperature sensor 102 and a pressure sensor 103, and controls a refrigerant-circulating system. When the degree of opening of the throttling device 4 is determined, first of all, either cooling operation or heating operation is determined. In the case of the cooling operation, an evaporating temperature Te is found on the basis of a composition α1 of a nonazeotropic mixture circulating in the refrigerant circuit, a temperature T1 detected by the first temperature sensor 101, and a temperature T2 detected by the second temperature sensor 102, and the degree of opening of the throttling device 4 is determined in order that the degree of superheat, SH=T2-Te, is at a target value corresponding to the composition α1 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant circulation system and a refrigerating / air-conditioning apparatus using a non-azeotropic mixed refrigerant in which several kinds of refrigerant are blended.

[0002]

2. Description of the Related Art FIG. 34 shows, for example, Japanese Patent Publication No. 6-12201.
No. 1 is a compressor, 5 is a load side heat exchanger, 4 is a refrigerating / air-conditioning apparatus using a conventional non-azeotropic mixed refrigerant.
Reference numerals a and 4b are main expansion devices, and 3 is a heat source side heat exchanger, which are connected by a refrigerant pipe to form a main circuit of a refrigeration cycle. 29 is a rectification tower, the tower top reservoir 31 is connected to the tower top by a refrigerant pipe 50 and a refrigerant pipe 51 in which a cooling source 30 is arranged, and a refrigerant pipe 52 is provided at the bottom of the rectification tower. And the refrigerant pipe 53 in which the heating source 32 is arranged, the tower overhead reservoir 33 is connected.

Between the load side heat exchanger 5 and the heat source side heat exchanger 3, a tower pipe reservoir 31 is connected by a refrigerant pipe 54 having an opening / closing valve 34, and an opening / closing valve 36 is installed. The tower bottom reservoir 33 is connected by a refrigerant pipe 55.
On the upstream side of the heat source side heat exchanger 3, a sub-throttle device 37 and an on-off valve 38 are installed by a refrigerant pipe 56 in which the overhead reservoir 31 is installed.
, And the bottom reservoir 33 is connected by a refrigerant pipe 57 in which an auxiliary expansion device 37 and an opening / closing valve 39 are installed. The outlet from the overhead reservoir 31 to the refrigerant pipe 56 is at the bottom of the overhead reservoir 11, and the bottom reservoir 33.
To the refrigerant pipe 57 are installed at the bottom of the tower bottom reservoir 33.

In the above structure, the vapor of the high-temperature and high-pressure non-azeotropic mixed refrigerant (hereinafter referred to as refrigerant) compressed by the compressor 1 flows in the direction of arrow A, is condensed in the load side heat exchanger 5, and is mainly condensed. Enter the diaphragm device 4a. Open / close valves 34, 36 during normal operation
Is closed, so enter the main diaphragm device 4b as it is,
The low-temperature low-pressure refrigerant evaporates in the heat source side heat exchanger 3 and returns to the compressor 1 again.

In the case of changing the composition of the refrigerant flowing through the main circuit, first, in order to make the composition of the refrigerant flowing through the main circuit rich in extremely high boiling point components, the on-off valves 38 and 34 are closed and the on-off valve 39 is closed. , 36 open. Then, a part of the refrigerant flowing out of the main expansion device 4a flows to the open / close valve 36, and the rest flows into the main expansion device 4b to flow in the same circuit as in the normal operation. The refrigerant flowing into the opening / closing valve 36 enters the tower bottom reservoir 33. The refrigerant that has entered the tower bottom reservoir 33 partially enters the sub expansion device 37 through the open / close valve 39, merges with the refrigerant that flows in the main circuit on the upstream side of the heat source side heat exchanger 3, and remains. Enters the refrigerant pipe 53 in which the heating source 32 is installed and is heated to rise in the refrigerant rectification column 29 as vapor. At this time, the refrigerant liquid stored in the overhead reservoir 31 also descends from the refrigerant pipe 50 in the refrigerant rectification column 29 and comes into gas-liquid contact with the rising refrigerant vapor to perform a so-called rectification action.

Thus, the refrigerant vapor becomes rich in low-boiling components as it rises, is introduced into the refrigerant pipe 51 in which the cooling source 30 is installed and is liquefied, and the on-off valve 38 is closed so that the overhead storage It is stored in the container 31. Such rectification action is repeated until finally the overhead reservoir 3
Only the refrigerant rich in a very low boiling point component is stored in 1. Therefore, the composition of the refrigerant flowing through the main circuit has been made rich in the components having a very high boiling point.

To make the composition of the refrigerant flowing through the main circuit rich in low-boiling components, the on-off valves 38 and 34 are opened and the on-off valves 39 and 36 are closed. Then, the main diaphragm device 4a
A part of the refrigerant flowing through the main circuit that has flowed out flows into the overhead reservoir 31 through the open / close valve 34 that is open, but since the open / close valve 38 is also open, The portion passes through the refrigerant pipe 4a, passes through the sub expansion device 37, and joins with the main circuit. Then, the remaining refrigerant enters the refrigerant rectification column 29 through the refrigerant pipe 50 and descends. At this time, a part of the refrigerant in the bottom reservoir 33 is heated by the heating source 32 to rise in the refrigerant rectification column and come into gas-liquid contact with the descending liquid to perform a so-called rectification action. In this way, the descending refrigerant liquid gradually becomes rich in high-boiling components, and is stored in the column bottom reservoir 33 because the on-off valve 39 is closed. Then, such rectification action is repeated, and finally, only the refrigerant rich in the extremely high boiling point component is stored in the column bottom reservoir 33. Therefore, the composition of the refrigerant flowing through the main circuit has been made rich in extremely low boiling point components. Regarding the technique of circulating the non-azeotropic mixed refrigerant, in addition to the above, Japanese Patent Publication No. 5-40221 and Japanese Patent Publication No. 6-2
Japanese Patent No. 3625 is known.

[0008]

In such a conventional refrigeration / air-conditioning apparatus, there is no means for detecting or judging the composition of the refrigerant, control is not performed according to the composition, and efficient operation is not always performed. I couldn't. In addition, the control is very complicated. An object of the present invention is to solve the above problems and to estimate the composition of the refrigerant circulating in the refrigerant circuit during operation and change the composition of the refrigerant. Further, the present invention performs control according to the composition of the refrigerant during operation. Further, the object of the present invention is to perform appropriate control according to the operating state, and to adjust the composition in a shorter time. Further, it is an object of the present invention to provide a system and apparatus using a non-azeotropic mixed refrigerant having higher reliability.

[0009]

According to a first aspect of the present invention, there is provided a refrigerant circulation system in which a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger and a low pressure receiver are sequentially connected, and several refrigerants are used. Circulates a non-azeotropic mixed refrigerant mixed with, the flow direction of the refrigerant in the refrigerant circulation system, the elapsed time from startup,
Operation determination means for determining each operation state such as load amount, storage means for storing the composition state of the refrigerant preset for each operation state, and storage means based on the operation state determined by the operation determination means From the refrigerant composition selection means for selecting the composition state of the refrigerant, and the refrigerant composition setting means for changing the composition of the refrigerant circulating through the refrigerant circulation system to the composition state of the refrigerant selected by the refrigerant composition selection means, is there.

In the refrigerant circulation system of the present invention according to claim 2, the refrigerant composition setting means for changing the composition of the refrigerant is the opening degree setting means of the expansion device.

The refrigerant circulation system of the present invention according to claim 3 is provided with a control means for determining a set value for controlling the operation of the refrigerant circulation system based on the composition state of the refrigerant selected by the refrigerant circulation composition selection means. Is.

According to a fourth aspect of the refrigerant circulation system of the present invention, a compressor, a heat source side heat exchanger, a throttling device, a load side heat exchanger and a low pressure receiver are sequentially connected, and a non-azeotropic mixture of several refrigerants is mixed. Circulating the mixed refrigerant, based on the operation determination means for determining the state of each operation of the refrigerant circulation system, and the operating state determined by this operation determination means, changing the set value of the operation control of the refrigerant circulation system, the refrigerant And a control means for controlling the circulation system.

In the refrigerant circulation system of the present invention according to claim 5, the target value of at least one of the evaporator outlet superheat degree and the condenser outlet supercooling degree is set as a set value for the operation control of the refrigerant circulation system. However, the control is performed according to this target value.

According to a sixth aspect of the present invention, there is provided a refrigerant circulation system in which a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger and a low pressure receiver are sequentially connected, and a non-azeotropic mixture of several refrigerants is mixed. A control means is provided which circulates the mixed refrigerant, changes the set value of the control of the refrigerant circulation system during cooling and heating, and controls the operation of the refrigerant circulation system.

According to a seventh aspect of the refrigerant circulation system of the present invention, a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger, and a low pressure receiver are sequentially connected, and a non-azeotropic mixture of several refrigerants is mixed. Using a mixed refrigerant, changing the set value of the control of the refrigerant circulation system during cooling, heating and the operating capacity of the compressor,
It is provided with a control means for controlling the operation of the refrigerant circulation system.

A refrigerant circulation system of the present invention according to claim 8 is a non-azeotropic mixture of several kinds of refrigerant, which is formed by sequentially connecting a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger and a low pressure receiver. The present invention is provided with a control means that uses a mixed refrigerant and changes the set value of the control of the refrigerant circulation system according to the time from the start of the compressor to control the operation of the refrigerant circulation system.

According to the ninth aspect of the refrigerant circulation system of the present invention, the set value of the control is changed every predetermined time or every major change of the operating condition.

In the refrigeration / air-conditioning system of the present invention according to claim 10, the compressor, the heat source side heat exchanger, the expansion device, the load side heat exchanger, and the low-pressure receiver are sequentially connected, and several types of refrigerant are mixed. A mechanism that circulates the azeotropic mixed refrigerant and estimates the composition of the refrigerant that circulates in the refrigerant circuit, and a controller that changes the set value of the refrigeration cycle control according to the detected composition of the refrigerant and performs control It is a thing.

The refrigeration / air-conditioning system of the present invention according to claim 11 is a non-azeotropic mixture in which a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger and a low pressure receiver are sequentially connected to mix refrigerants. In a refrigeration cycle using a refrigerant, a means for detecting the temperature and pressure of a place where the refrigerant becomes saturated near the heat source side heat exchanger or the load side outlet is provided, and by this detected value, the composition of the refrigerant circulating in the refrigerant circuit. To change the set value of the refrigeration cycle control according to the calculated composition value,
And a controller for controlling the refrigeration cycle.

In the refrigeration / air-conditioning apparatus of the present invention according to claim 12, of the heat source side heat exchanger and the load side heat exchanger, temperature detecting means for detecting the refrigerant temperature at the outlet of the heat exchanger serving as an evaporator, Pressure detecting means for detecting the refrigerant pressure at the outlet of the evaporator is provided. Further, the refrigeration / air-conditioning apparatus of the present invention according to claim 13 is pressure detecting means for detecting the refrigerant pressure at the heat exchanger outlet of the heat source side heat exchanger and the load side heat exchanger, which is a condenser, Temperature detecting means for detecting the temperature of the refrigerant at the outlet of the condenser.

In the refrigeration / air-conditioning system of the present invention according to claim 14, a compressor, a heat source side heat exchanger, a high pressure receiver, a throttling device, and a load side heat exchanger are sequentially connected, and a non-coexistence system in which several refrigerants are mixed is used. In a refrigeration cycle using a boiling mixed refrigerant, a temperature detecting means for detecting the refrigerant temperature inside the high pressure receiver, a pressure detecting means for detecting the refrigerant pressure inside the high pressure receiver, and a detection value of the temperature detecting means and the pressure detecting means, A controller for calculating the composition of the refrigerant circulating in the refrigerant circuit, changing the setting value of the refrigeration cycle control according to the composition calculation value, and controlling the refrigeration cycle.

According to the fifteenth aspect of the refrigeration / air-conditioning system of the present invention, the saturation temperature of the refrigerant gas is calculated according to the composition of the refrigerant circulating in the estimated or calculated refrigerant circuit, and the evaporator outlet superheat degree is calculated. Or a throttle device for changing the opening so that the degree of supercooling at the condenser outlet becomes a predetermined value.

The refrigeration / air-conditioning apparatus of the present invention according to claim 16 comprises a compressor, a four-way valve, a heat source side heat exchanger, a supercooling heat exchanger, a first expansion device, a load side heat exchanger and a low pressure receiver. In a refrigeration cycle using a non-azeotropic mixed refrigerant in which several refrigerants are mixed in sequence, branched from the refrigerant circuit between the heat source side heat exchanger and the first expansion device, the second expansion device and the above Via a supercooling heat exchanger, a bypass pipe connected to a low-pressure gas pipe, a first temperature detecting means for detecting the refrigerant temperature at the inlet of the second expansion device, and a refrigerant at the outlet of the second expansion device. Second temperature detecting means for detecting the temperature, the pressure detecting means for detecting the refrigerant pressure of the second expansion device outlet, by the detection value of the first and second temperature detecting means and the pressure detecting means, Calculate the composition of the refrigerant circulating in the refrigerant circuit Change the set value of the control of the refrigerating cycle in accordance with the composition calculated value, in which a main controller for controlling the refrigeration cycle.

The refrigeration / air-conditioning system according to the seventeenth aspect of the present invention is provided with a third expansion device between the heat source side heat exchanger and the supercooling heat exchanger.

According to the eighteenth aspect of the refrigeration / air-conditioning system of the present invention, the bypass pipe inlet is provided at the bottom of the main pipe.

In the refrigerating / air-conditioning apparatus of the present invention according to claim 19, a refrigerant agitating portion is provided upstream of the main pipe near the branch portion of the bypass.

In the refrigeration / air-conditioning system of the present invention according to claim 20, a plurality of load side heat exchangers are provided, and refrigerant pipes of the stopped load side heat exchangers are used as the composition adjusting means.

A refrigeration / air-conditioning system of the present invention according to claim 21 is a compressor, a four-way valve, a heat source side heat exchanger, a second expansion device, a high pressure receiver, a first expansion device, a load side heat exchanger, and In a refrigeration cycle configured by a low-pressure receiver or the like and using a non-azeotropic mixed refrigerant in which several refrigerants are mixed, a first temperature detecting means for detecting a temperature between the load side heat exchanger and the first expansion device, A second temperature detecting means for detecting a temperature between the first expansion device and the high pressure receiver, and a third temperature detecting means for detecting a temperature between the heat source side heat exchanger and the second expansion device. , A fourth temperature detecting means for detecting a temperature between the second expansion device and the high-pressure receiver, a fifth temperature detecting means for detecting a temperature between the four-way valve and the load side heat exchanger, and Sixth temperature to detect the temperature between the four-way valve and the heat source side heat exchanger Output means, first pressure detecting means for detecting pressure between the load side heat exchanger and the first expansion device, and pressure detection between the heat source side heat exchanger and the second expansion device. It is provided with a second pressure detecting means, a computing device for computing the composition of the refrigerant circulating in the refrigerant circuit, and a main controller for computing and controlling the openings of the first and second expansion devices.

A refrigeration / air-conditioning system of the invention according to claim 22 is a compressor, a four-way valve, a heat source side heat exchanger, a second expansion device, a high pressure receiver, a first expansion device, a load side heat exchanger, and In a refrigeration cycle configured by a low-pressure receiver or the like and using a non-azeotropic mixed refrigerant in which several refrigerants are mixed, a bypass pipe connecting the high-pressure receiver and the low-pressure receiver, and a third throttle installed on the bypass pipe Device, a first temperature detecting means for detecting the temperature between the low pressure receiver and the third expansion device, a second temperature detection means for detecting the temperature between the third expansion device and the high pressure receiver, Third temperature detecting means for detecting the temperature between the load side heat exchanger and the first expansion device, and fourth temperature detecting means for detecting the temperature between the four-way valve and the load side heat exchanger, , The second expansion device and the heat source side heat Fifth temperature detecting means for detecting the temperature between the exchangers, sixth temperature detecting means for detecting the temperature between the four-way valve and the heat source side heat exchanger, a third expansion device and a low pressure receiver. A first pressure detecting means for detecting the pressure between, a second pressure detecting means for detecting the pressure on the discharge side of the compressor, an arithmetic device for calculating the composition of the refrigerant circulating in the refrigerant circuit, A composition regulator that determines the opening of the third expansion device and adjusts the composition, and a main controller that calculates and controls the openings of the first and second expansion devices.

A refrigeration / air-conditioning system according to a twenty-third aspect of the present invention comprises a main pipe before and after the high pressure receiver, and a supercooling heat exchanger for exchanging heat between the third throttle device and the pipe between the low pressure receiver.

According to a twenty-fourth aspect of the present invention, there is provided a refrigeration / air-conditioning system of the present invention, which comprises a bypass pipe connecting the compressor discharge side pipe and a suction side pipe of the low pressure receiver, and an opening / closing mechanism on the bypass pipe.

The refrigeration / air-conditioning system of the present invention according to claim 25 is installed between the high-pressure receiver and the second expansion device, and the first opening / closing mechanism installed between the high-pressure receiver and the first expansion device. Bypass piping that bypasses the second opening / closing mechanism and the first opening / closing mechanism and connects the third opening / closing mechanism to the first subcooling heat exchanger, and bypasses the second opening / closing mechanism and the fourth opening / closing mechanism. A low-pressure receiver includes the first and second supercooling heat exchangers, and a bypass pipe that connects the mechanism and the second supercooling heat exchanger.

According to a twenty-sixth aspect of the refrigeration / air-conditioning system of the present invention, a low-pressure receiver is divided into a portion for storing liquid refrigerant,
A buffer portion is provided to prevent temporary liquid return to the compressor.

A refrigeration / air-conditioning system of the present invention according to claim 27 is a refrigeration cycle in which a compressor, a condenser, a throttle device and an evaporator are sequentially connected, and a non-azeotropic mixed refrigerant in which several refrigerants are mixed is used, Branch from the refrigerant circuit between the heat source side heat exchanger and the first expansion device, through the second expansion device and the supercooling heat exchanger, a bypass pipe connected to the low-pressure gas pipe, and First temperature detecting means for detecting the refrigerant temperature at the second throttle device inlet, second temperature detecting means for detecting the refrigerant temperature at the second throttle device outlet, and refrigerant at the second throttle device outlet Pressure detecting means for detecting pressure, dryness detecting means installed near a branch portion of the main pipe with the bypass pipe, the first and second temperature detecting means, the pressure detecting means and the dryness detecting means Depending on the detected value of A composition calculation device that calculates the composition of the refrigerant circulating in the refrigerant circuit, and a main controller that changes the set value of the refrigeration cycle control according to the composition calculation value and controls the refrigeration cycle. is there.

[0035]

In the refrigerant circuit in which the compressor, the heat source side heat exchanger, the expansion device, the load side heat exchanger and the low pressure receiver are sequentially connected, the present invention according to claim 1 is a non-azeotropic mixture of several kinds of refrigerant. Using the mixed refrigerant, the composition of the target refrigerant that circulates in the refrigerant circuit (hereinafter referred to as the circulation composition) is determined from the operating state, and the refrigerant composition setting means adjusts the circulation composition to the target circulation composition. Therefore, the circulation composition of the non-azeotropic mixed refrigerant suitable for the operating state is always maintained. The present invention according to claim 2 changes the composition of the refrigerant by setting the opening degree of the expansion device.

According to a third aspect of the present invention, in a refrigerant circuit in which a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger, and a low pressure receiver are sequentially connected, a non-azeotropic mixture of several kinds of refrigerant is used. The mixed refrigerant is used to calculate and set the control value for the operation of the refrigerant circulation system according to the circulation composition selected based on the operating state. According to a fourth aspect of the present invention, the operating state of the refrigerant system is determined and the control set value is changed. According to the fifth aspect of the present invention, at least one of the evaporator outlet superheat degree and the condenser outlet supercooling degree is controlled as a target value.

According to a sixth aspect of the present invention, in a refrigerant circuit in which a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger, and a low-pressure receiver are sequentially connected, a non-azeotropic mixture of several kinds of refrigerant is used. The mixed refrigerant is used to control the operation by changing the control parameters of the refrigerant circulation system during cooling and heating.

According to a seventh aspect of the present invention, in a refrigerant circuit in which a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger and a low pressure receiver are sequentially connected, a non-azeotropic mixture of several kinds of refrigerant is used. The mixed refrigerant is used to control the operation by changing the control parameters of the refrigerant circulation system according to the cooling capacity, the heating status, and the operating capacity of the compressor.

In the refrigerant circuit in which the compressor, the heat source side heat exchanger, the expansion device, the load side heat exchanger and the low pressure receiver are sequentially connected, the present invention according to claim 8 is a non-azeotropic mixture of several kinds of refrigerant. By using a mixed refrigerant, the control parameters are changed, the operation is controlled, and the startup characteristics are improved depending on the time from the start of the compressor.

According to the ninth aspect of the present invention, the set value of the control of the refrigerant circulation system is changed every predetermined time period or every large change of the operating state, and the control following the change is performed.

According to a tenth aspect of the present invention, in a refrigerant circuit in which a compressor, a heat source side heat exchanger, an expansion device, a load side heat exchanger and a low pressure receiver are sequentially connected, a non-azeotropic mixture of several kinds of refrigerant is used. Using the mixed refrigerant, the composition of the refrigerant circulating in the refrigerant circuit (hereinafter referred to as the circulation composition) is estimated. A set value for control of the refrigeration cycle is calculated based on the estimated composition, the circulation composition is adjusted to a target circulation composition by the composition adjusting means, and control according to the circulation composition is performed.

The present invention according to claim 11 detects the temperature and pressure at a place where the refrigerant becomes saturated, obtains the composition of the refrigerant from these values, and changes the set value for control of the refrigeration cycle according to this composition. Control.

According to the twelfth aspect of the present invention, of the heat source side heat exchanger and the load side heat exchanger, the pressure and temperature of the refrigerant are detected at the heat exchanger outlet serving as an evaporator, and the detected pressure and temperature are detected. The circulation composition is calculated and the refrigeration cycle is controlled.

In the thirteenth aspect of the present invention, of the heat source side heat exchanger and the load side heat exchanger, the pressure and temperature of the refrigerant are detected at the heat exchanger outlet serving as a condenser, and the detected pressure and temperature are detected. The circulation composition is calculated and the refrigeration cycle is controlled.

According to the fourteenth aspect of the present invention, the pressure and temperature of the refrigerant inside the high-pressure receiver in which the saturated liquid surface exists is detected,
The circulation composition is calculated from the detected pressure and temperature to control the refrigeration cycle.

According to the fifteenth aspect of the present invention, the saturation temperature of the refrigerant gas is calculated in accordance with the estimated or calculated composition of the refrigerant circulating in the refrigerant circuit, and the evaporator outlet superheat degree,
Alternatively, the opening degree of the expansion device is changed so that the degree of supercooling at the condenser outlet becomes a predetermined value.

According to the sixteenth aspect of the present invention, a low-pressure gas is branched from the refrigerant circuit between the heat source side heat exchanger and the first expansion device, and passes through the second expansion device and the supercooling heat exchanger. A bypass pipe connected to the pipe, a first temperature detecting means for detecting the refrigerant temperature at the second throttle device inlet, a second temperature detecting means for detecting the refrigerant temperature at the second throttle device outlet, and a second Pressure detecting means for detecting the refrigerant pressure at the outlet of the expansion device,
The composition of the refrigerant circulating in the refrigerant circuit is calculated based on the detection values of the temperature detection means and the pressure detection means, and the set value of the refrigeration cycle control is changed in accordance with the calculated composition value to control the refrigeration cycle.

According to a seventeenth aspect of the present invention, a third expansion device is provided between the heat source side heat exchanger and the subcooling heat exchanger, and the vicinity of the bypass pipe inlet is in a liquid state during cooling and heating. To do.

According to the eighteenth aspect of the present invention, by installing the branch portion of the main pipe and the bypass pipe downward with respect to the main pipe, the liquid of the refrigerant is always guided to the bypass pipe.

According to the nineteenth aspect of the present invention, the refrigerant stirring section is provided upstream of the main pipe in the vicinity of the bypass pipe branch.

The present invention according to claim 20 provides a load side heat exchanger in which the circulating composition control means is stopped, and when the composition is adjusted, refrigerant is stored in the stopped load side heat exchanger. discharge.

According to the twenty-first aspect of the present invention, during cooling operation, the detected value of the temperature between the load side heat exchanger and the first expansion device and the temperature between the first expansion device and the high pressure receiver are detected. The circulating composition is calculated by the calculation device from the detected value and the detected value of the pressure between the load side heat exchanger and the first expansion device. During heating operation, the detected value of the temperature between the heat source side heat exchanger and the second expansion device, the detected value of the temperature between the second expansion device and the high-pressure receiver, the heat source side heat exchanger and the second The circulation composition is calculated by the calculation device from the detected value of the pressure between the expansion devices. Furthermore,
In the main controller, the openings of the first and second expansion devices are calculated, and control is performed according to the composition.

According to a twenty-second aspect of the present invention, on a bypass pipe connecting the high-voltage receiver and the low-voltage receiver,
The temperature and pressure are detected, and the circulating composition is calculated by the calculation device from the detected values. The composition adjuster determines the opening degree of the third expansion device so that the calculated circulation composition becomes the target circulation composition. The main controller determines the rotation speed of the compressor, the rotation speed of the fan of the heat source side heat exchanger, and the opening degree of the expansion device according to the calculated circulation composition.

The present invention according to claim 23 provides a subcooling heat exchanger for exchanging heat between the main pipe before and after the high pressure receiver and the pipe between the third expansion device and the low pressure receiver, and by exchanging heat, The enthalpy of the refrigerant flowing through the bypass pipe is transmitted to the refrigerant flowing through the main circuit.

According to a twenty-fourth aspect of the present invention, a bypass pipe connecting the compressor discharge side pipe and the suction side pipe of the low pressure receiver is provided, and the liquid refrigerant inside the low pressure receiver is discharged from the compressor at a high temperature. Evaporate quickly with gas.

The present invention according to claim 25 provides a first opening / closing mechanism installed between the high-voltage receiver and the first diaphragm device, and a second opening-closing mechanism installed between the high-voltage receiver and the second diaphragm device. And a bypass pipe that bypasses the first opening / closing mechanism and connects the third opening / closing mechanism to the first subcooling heat exchanger, bypasses the second opening / closing mechanism, and connects the fourth opening / closing mechanism and the second opening / closing mechanism. By providing a bypass pipe that communicates the subcooling heat exchanger and incorporating the first and second subcooling heat exchangers in the low-pressure receiver, the liquid refrigerant inside the low-pressure receiver can be quickly transferred by the high-pressure and high-temperature liquid pipes. And the latent heat of evaporation when the refrigerant liquid is evaporated inside the low-pressure receiver is transferred to the refrigerant flowing through the main circuit.

According to the twenty-sixth aspect of the present invention, the low-pressure receiver is divided, a portion for storing the liquid refrigerant and a buffer portion for preventing temporary liquid return to the compressor are provided, and liquid return to the compressor is prevented. To do.

According to a twenty-seventh aspect of the present invention, during cooling operation, temperature detecting means for detecting the refrigerant temperature at the inlet / outlet of the second expansion device and pressure detecting means for detecting the refrigerant pressure at the outlet of the second expansion device. Is calculated, the composition of the refrigerant circulating in the refrigerant circuit is calculated, and the composition is adjusted by the composition adjusting means so that the composition becomes a target composition. During the heating operation, the temperature detecting means for detecting the refrigerant temperature at the outlet of the second expansion device, the pressure detecting means for detecting the pressure of the refrigerant at the outlet of the second expansion device, and the vicinity of the branch part of the bypass pipe in the main pipe. The composition of the refrigerant circulating in the refrigerant circuit is calculated from the value detected by the dryness detecting means for detecting the dryness of the refrigerant, and the composition is adjusted by the composition adjusting means so as to obtain a target composition.

[0059]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. First Embodiment FIG. 1 is a refrigerant circuit diagram showing a first embodiment of the present invention. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is a heat source side heat exchanger, 4 is a throttle device, 5 is a load side heat exchanger, and 6 is a low-pressure receiver. It forms a refrigerant circuit. Further, 101 is a first temperature sensor, 10
Reference numeral 2 is a second temperature sensor, 103 is a pressure sensor, and 100 is a controller that determines the opening degree of the expansion device from the information of the first temperature sensor, the second temperature sensor, and the pressure sensor, and performs control. . When the sensing positions are different or common in cooling and heating, the flow of the refrigerant is reversed between cooling and heating, so that the condenser and the evaporator cannot be specified. Therefore, a heat exchanger that serves as a condenser during cooling and an evaporator during heating is used as a heat source side heat exchanger. The load side heat exchanger shows the opposite.

The operation will be described. During cooling, as shown in the flow of the refrigerant in FIG. 1, the refrigerant is discharged from the compressor 1, condensed in the heat source side heat exchanger 3, condensed by the expansion device 4, and brought into a low-temperature / low-pressure two-phase state. Become. The low-temperature low-pressure two-phase refrigerant flows into the load-side heat exchanger 5 and takes heat from the surroundings to cool it, and at the same time evaporates and vaporizes itself to the compressor 1 via the four-way valve 2 and the low-pressure receiver 6. Return.

During heating, the refrigerant is discharged from the compressor 1,
In the load side heat exchanger 5, heat is released to the surroundings for heating, and at the same time, the heat condenses and liquefies itself, and is throttled by the expansion device 4 to become a low temperature / low pressure two-phase state. The low-temperature low-pressure two-phase refrigerant flows into the heat source side heat exchanger 3, evaporates and vaporizes, and returns to the compressor 1 via the four-way valve 2 and the low pressure receiver 6. Furthermore, to detect the driving condition and judge the driving condition,
For example, the mode such as cooling or heating can be determined if it is linked to the mode changeover switch. Alternatively, the temperature of the inlet or the outlet of the heat exchanger may be detected to determine the flowing direction of the refrigerant. It is possible to judge the operating state from the ON-OFF of the four-way valve.

The change in the excess refrigerant amount and the circulation composition will be described. First, regarding the amount of excess refrigerant generated, the amount of excess refrigerant is generally determined by cooling or heating once the refrigerant circuit is determined. Therefore, the amount of surplus refrigerant generated in cooling and heating can be estimated in advance. 2 shows the relationship between the liquid level of the low pressure receiver 6 and the circulating composition. As shown in the figure, as the amount of refrigerant inside the low-pressure receiver increases, the circulation composition increases. Therefore, by using these relationships, it is possible to predict in advance how much the circulation composition in cooling and heating will be. That is, the composition state of the refrigerant corresponding to the state of each operation may be set and stored in advance, and the composition state may be selected from these depending on the determined operation state.

FIG. 3 is a flow chart of the process of determining the opening degree of the expansion device 4 during cooling and heating. The opening degree of the expansion device 4 is determined as follows based on the circulation composition estimated in advance as described above. First, it is determined whether this is cooling or heating (ST01). In the case of cooling, the circulation composition is set to α ₁ (ST02), and the evaporation temperature t _e is obtained from this α ₁ and the temperature T1 detected by the first temperature sensor 101 and the temperature T2 detected by the second temperature sensor 102. (ST03), then
The throttle device 4 so that SH = T2-Te, which is the degree of superheat at the outlet of the evaporator, becomes constant at a target value determined according to the composition α _1.
The opening degree of is determined (ST05, ST06).

During heating (ST01), the circulating composition is set to α ₂ (ST07), and the condensation temperature TC is calculated from this α ₂ and the pressure P detected by the pressure sensor 103 (ST08). T
From C and the temperature T2 detected by the second temperature sensor 102,
The condenser outlet supercooling degree is calculated from SC = TC-T2 (ST09). The opening degree of the expansion device 4 is determined (ST11) so that the condenser outlet supercooling degree SC becomes constant at the target value (ST10). As a result, efficient operation can be performed with simple control.

As described above, for example, by changing the value of SC in particular, the surplus refrigerant moves from the low pressure receiver to the condenser or vice versa. Therefore, the liquid level of the low-pressure receiver fluctuates and the composition changes. Next, this procedure will be described. First, narrow down the aperture. This increases SC. Therefore, the liquid level of the low-pressure receiver is lowered. The proportion of low boiling components in the circulating composition will be reduced. In this way, changing the aperture of the throttle leads to a change in composition through an increase / decrease in SC and an increase / decrease in the liquid level of the low-pressure receiver. In this case, the controller detects the composition from the direct or indirect detection means of the circulation composition, obtains the opening degree from the detection means of the throttle, and operates the means for adjusting the circulation composition. In general, the circulation composition is the proportion of low-boiling components, and when the decrease in the low-pressure receiver decreases, the proportion of low-boiling components decreases as the high-boiling components increase in the circulation circuit.

To change the control set value, SH,
It is a common idea to change the target value of SC, and in the case of multiple models, change the target high pressure, which is the target pressure for controlling the discharge pressure of the compressor to keep the condensing temperature constant. is there. Note that SC is Tc (condensation temperature, strictly speaking, saturated liquid temperature) -Tc out (condenser outlet temperature). Further, SH is Te out (evaporator outlet temperature) -Te (evaporation temperature, strictly speaking, saturated gas temperature). In the non-azeotropic mixed refrigerant, the boiling start temperature (boiling point) and the condensation start temperature (dew point) are different even at the saturation temperature.

In the above, one embodiment has been described in which the control for keeping the SH superheat degree at the evaporator outlet constant during cooling and the control for keeping the SC degree of cooling SC at the condenser outlet during heating are described. And the control for keeping the superheat degree at the evaporator outlet constant or the control for keeping the supercool degree at the condenser outlet constant.

Example 2. Embodiment 2 of the present invention will be described below with reference to the drawings. FIG. 4 is a refrigerant circuit diagram showing Embodiment 2 of the present invention. In the figure, 1 is a compressor, 2 is a four-way valve,
3 is a heat source side heat exchanger, 4 is a throttle device, 5 is a load side heat exchanger, and 6 is a low-pressure receiver.
It forms the main refrigerant circuit. Further, 106 is the first temperature sensor, 107 is the second temperature sensor, 103 is the pressure sensor, 100 is the opening of the expansion device from the information of the first temperature sensor, the second temperature sensor, and the pressure sensor. Decide,
It is a controller that controls. The load side heat exchanger is a,
b It has a multi-circuit of two series.

The operation will be described. During cooling, as shown in the flow of the refrigerant in FIG. 4, the refrigerant is discharged from the compressor 1, condensed in the heat source side heat exchanger 3, condensed by the expansion device 4, and brought into a low temperature / low pressure two-phase state. Become. The low-temperature low-pressure two-phase refrigerant flows into the load-side heat exchanger 5 and takes heat from the surroundings to cool it, and at the same time evaporates and vaporizes itself to the compressor 1 via the four-way valve 2 and the low-pressure receiver 6. Return. The load side heat exchanger can be operated only at 5a or 5b.

During heating, the refrigerant is discharged from the compressor 1,
In the load side heat exchanger 5, heat is released to the surroundings for heating, and at the same time, the heat condenses and liquefies itself, and is throttled by the expansion device 4 to become a low temperature / low pressure two-phase state. The low-temperature low-pressure two-phase refrigerant flows into the heat source side heat exchanger 3, evaporates and vaporizes, and returns to the compressor 1 via the four-way valve 2 and the low pressure receiver 6. The load side heat exchanger can be operated only at 5a or 5b.

The change in the excess refrigerant amount and the circulation composition will be described. First, regarding the amount of excess refrigerant generated, the amount of excess refrigerant is generally determined by cooling or heating once the refrigerant circuit is determined. In addition, since the amount of surplus refrigerant also depends on the operating number of load-side heat exchangers, the operating number of load-side heat exchangers is also roughly understood from the operating frequency of the compressor. As a result, the amount of surplus refrigerant generated in cooling and heating can be estimated more accurately in advance by adding information on the operating frequency of the compressor. FIG. 5 shows the relationship between the liquid level of the low pressure receiver 6 and the circulating composition. As shown in the figure, as the amount of refrigerant inside the low-pressure receiver increases, the circulation composition increases. Therefore, using these relationships, the circulating composition in cooling and heating can be estimated by the operating frequency of the compressor.

The degree of opening of the expansion device 4 is determined as follows from the circulation composition estimated from the operating frequency of the compressor as described above. The circulating composition α ₁ during cooling is obtained from the operating frequency of the compressor, and the temperature T detected by the first temperature sensor 107 is used.
The opening degree of the expansion device 4 is determined so that the difference SH = T1-T2 between 1 and the temperature T2 detected by the second temperature sensor 106 becomes constant.

The circulation composition α ₂ during heating is obtained from the operating frequency of the compressor, and the condensation temperature TC is calculated from the pressure P detected by the pressure sensor 105. TC and the second temperature sensor 106
From the temperature T2 detected by the
Calculate from TC-T2. This condenser outlet supercooling degree SC
The opening degree of the expansion device 4 is determined so that is constant. As a result, with simple control, efficient operation can be performed even in a multi-refrigerant circuit having a plurality of heat exchangers.

An example of estimating the composition of the refrigerant in FIG. 5 is shown in FIGS. 6 and 7. The data in FIG. 7 can be determined in advance by experiments or the like. During cooling or heating (ST13),
Depending on the frequency level of the compressor (ST14, ST2
0), the stored circulation composition may be obtained (ST15,
ST21). Temperature and pressure are measured, evaporation temperature and condensation temperature are calculated (ST16, ST22), and SH and SC are calculated (S
T17, ST23), and according to the target value (ST18, S
T24), the operating frequency of the compressor, the operating mode, and the circulation composition can be associated from these data by changing the opening degree. Further, FIG. 8 shows an example of changes other than the valve opening degree. In FIG. 8, k ₁ and k ₂ are constants and Δ
S is the opening change amount of the expansion device. The evaporation temperature Te is detected during cooling. SH is obtained as the difference between the detected Te and the evaporator outlet. Difference Δ between SH value and SH target value
SH is calculated, and the opening degree of the expansion device is changed according to the amount of ΔSH. Further, the rotation frequency Δfcomp of the compressor is calculated according to the difference ΔTe between the target value Te and Te. During heating, the condensing temperature Tc is detected. This detected Tc
And SC as the difference between the condenser outlet and the condenser outlet. SC value and S
The difference ΔSC from the target value of C is calculated, and the opening of the diaphragm device is changed according to the amount of ΔSC. Further, according to the difference ΔTc between the target value of Tc and Tc, the rotation frequency Δfco of the compressor
Calculate mp. As a result, the target value is set for the evaporation temperature during cooling, the target value is set for the condensation temperature during heating, and the frequency of the compressor is changed so as to reach the target value.

As described above, by changing SC and SH,
In addition to the change in the liquid level of the low-pressure receiver, it is estimated from the operating frequency of the compressor which capacity of the indoor unit is operating in the case of multiple models. Here, if the operation capacity of the indoor unit is small, the refrigerant remains as long as the stagnation in the indoor unit is not considered. In other words, the smaller the operating frequency of the compressor,
Excess refrigerant accumulates in the low-pressure receiver, and the circulating composition becomes rich in low-boiling components. Furthermore, it can be said that the number of operating indoor units (capacity) is large when the operating frequency of the compressor is high. The difference between the number of units and the capacity may be one indoor unit that exhibits a large capacity even with the same capacity, or may be a large number of units having a small capacity. As a result, although there is some variation, the tendency that the excess refrigerant decreases as the capacity increases becomes the same.

The set value of the opening degree of the expansion device 4 can be changed depending on the operation mode, frequency conditions and the like. That is, depending on the set value, the opening is changed to correspond to this set value. Along with this, the circulating composition gradually changes to a corresponding composition. At this time, the load state of the system is changed by changing the opening degree. Moreover, a similar load change occurs even if the composition is changed, and as a result, the frequency is added. For this, it is advisable to detect the opening of the throttle and the operating frequency of the compressor at regular intervals (for example, every one minute) to change the set value.
However, this cycle does not always match the cycle of changing the operating frequency of the compressor or changing the opening of the throttle. Alternatively, the set value may be changed only when the mode switching and the fluctuation of the operating frequency of the compressor are large. With these controls, it is possible to perform highly accurate control that follows changes in operating conditions.

Example 3. Embodiment 3 of the present invention will be described below with reference to the drawings. FIG. 9 is a refrigerant circuit diagram showing Embodiment 3 of the present invention. In the figure, 1 is a compressor, 3 is a heat source side heat exchanger, 4 is a throttle device, 5 is a load side heat exchanger, and 6 is a low pressure receiver, and these are sequentially connected to form a main refrigerant circuit. Further, 101 is a first temperature sensor, and 102
Is a second temperature sensor, and 100 is a controller that determines the opening degree of the expansion device based on the information of the first temperature sensor and the second temperature sensor, and performs control.

The operation will be described. The refrigerant is the compressor 1
Is discharged from the heat source side, condensed in the heat source side heat exchanger 3, and throttled by the expansion device 4 to be in a low temperature / low pressure two-phase state. The low-temperature low-pressure two-phase refrigerant flows into the load-side heat exchanger 5 to remove heat from the surroundings and cool, and at the same time evaporates itself and returns to the compressor 1 via the low-pressure receiver 6.

When the compressor is started up, the low pressure receiver 6 is filled with the refrigerant liquid due to the sleeping refrigerant and the liquid bag when the compressor is started up. After that, the distribution of the refrigerant in the refrigerant circuit becomes appropriate, and the amount of the refrigerant liquid inside the low-pressure receiver decreases. When the amount of refrigerant liquid inside the low pressure receiver decreases,
Since the circulating composition also decreases, the circulating composition also decreases depending on the time from the start of the compressor, as shown in FIG. 10, for example.
Therefore, the circulation composition α is estimated from the time from the start of the compressor, and the difference SH = T between the temperature T1 detected by the first temperature sensor 101 and the temperature T2 detected by the second temperature sensor 102.
The opening degree of the expansion device 4 is determined so that 1-T2 is constant. At this time, the target value of the load side heat exchanger outlet superheat degree SH is changed according to the circulation composition which changes with time. As a result, the time from the start of the compressor to the steady state is shortened.

At the time of start-up, liquid refrigerant is often accumulated in the low-pressure receiver due to liquid return or stagnation, and the circulating composition is rich in low-boiling components. Therefore, SH = T1-T
By setting the target value of 2 in accordance with the composition, it is possible to prevent the aperture from being too narrow or being opened too much. As a result, the liquid refrigerant in the low-pressure receiver can be smoothly moved to the condenser at startup. As a result, the time from the start of the compressor to the steady state of the refrigerant circuit can be shortened.

The starting state in which the above-mentioned control is performed and the state considered to be steady are detected, for example, from the time from the start or the high pressure is detected every minute, and the fluctuation range of 3 minutes is detected. It may be divided from the data such as when it becomes equal to or less than the predetermined value (the time interval is not limited to 1 minute).

In Examples 1 to 3, the amount of surplus refrigerant present in the low-pressure receiver can be predicted to some extent depending on the operating mode, the operating frequency of the compressor, the start-up time, etc. In general, refrigeration using a non-azeotropic mixed refrigerant is used. Refrigerant in a low-pressure receiver such as a cycle accumulator is separated into a liquid phase rich in high-boiling components and a gas phase rich in low-boiling components, and the liquid phase rich in high-boiling components is stored in the accumulator. . Therefore, when the liquid refrigerant is present in the accumulator, the refrigerant composition circulating in the refrigeration cycle tends to have a large amount of low-boiling components (the circulation composition increases). The relationship between the refrigerant liquid level height h in the accumulator and the circulation composition α is such that the refrigerant liquid level height in the accumulator increases. That is, as the amount of liquid refrigerant in the accumulator increases, the circulation composition increases. Therefore, if you investigate this relationship beforehand by experiments,
The circulation composition α can be estimated from the refrigerant liquid level height h in the accumulator detected by the liquid level detector or the like. As described above, the circulation composition is adjusted according to the operating state, and the composition state of the non-azeotropic mixed refrigerant adapted to the operating state is always maintained, so stable operation is possible, the operation reliability is high, and the capacity is always sufficient. It is possible to obtain a refrigerant circulation system that can be demonstrated.

Embodiment 4 FIG. Embodiment 4 of the present invention will be described below with reference to the drawings. FIG. 11 is a refrigerant circuit diagram showing Embodiment 4 of the present invention. In the figure, 1 is a compressor, 3 is a heat source side heat exchanger, 4 is a throttle device, 5 is a load side heat exchanger, and 6 is a low pressure receiver, and these are sequentially connected to form a main refrigerant circuit. Further, 101 is a first temperature sensor, 10
3 is a first pressure sensor, 106 is a second temperature sensor, 1
Reference numeral 05 is a second pressure sensor, and 100 is a controller that calculates the circulation composition from the information of the first temperature sensor and the first pressure sensor, determines the opening degree of the expansion device, and controls. .

The operation will be described. The refrigerant is the compressor 1
Is discharged from the heat source side, condensed in the heat source side heat exchanger 3, and throttled by the expansion device 4 to be in a low temperature / low pressure two-phase state. The low-temperature low-pressure two-phase refrigerant flows into the load-side heat exchanger 5 to remove heat from the surroundings and cool, and at the same time evaporates itself and returns to the compressor 1 via the low-pressure receiver 6.

The controller has a function of calculating the circulation composition α,
It has a function of driving the diaphragm device 4. The circulation composition α is calculated from the temperature T1 detected by the first temperature sensor and the pressure P detected by the first pressure sensor. FIG. 12 is a diagram in which the composition of the refrigerant is plotted on the horizontal axis and the temperature is plotted on the vertical axis under a constant pressure. In the figure, the saturated vapor temperature is shown by a broken line, the saturated liquid temperature is shown by a one-dot chain line, and the line of the dryness X = 0.9 of the refrigerant is shown by a solid line. From the figure, it can be seen that the composition is uniquely determined when the pressure, the temperature, and the dryness of the refrigerant are determined in the two-phase portion. Therefore, the dryness of the evaporator outlet refrigerant is generally set to 0.
Considering about 9, the circulation composition can be obtained from the temperature T and the pressure P. The controller calculates the condensation temperature Tc from the calculated circulation composition and the value P2 detected by the second pressure sensor 105. The condenser outlet supercooling degree SC is calculated from SC = Tc-T2 based on the difference between the value T2 detected by the second temperature sensor and the condensation temperature Tc. As a result, the degree of supercooling of the refrigerant at the condenser outlet is optimized,
Efficient operation can be performed.

In FIG. 12, the horizontal axis represents the proportion (%) of the high boiling point component. Further, to make the degree of supercooling of the refrigerant appropriate means to bring it close to the target value. First, the composition α is calculated, then Tc is calculated, SC is calculated, and the difference between the calculated SC and the target SC is large. For example, the opening degree of the difference is obtained, α is calculated again, and the calculation is repeated to make SC appropriate. If SC is too large, in the heat exchanger, the proportion of the liquid portion in the gas portion, the two-phase portion, and the liquid portion increases, and the efficiency of the heat exchanger decreases. On the other hand, if SC is too small, the heat exchanger outlet will be in a two-phase state, and a refrigerant noise will be produced, or the refrigerant will not be distributed well in multiple models. Therefore, by making SC appropriate, it is possible to obtain an efficient system in which no abnormality occurs.

Example 5. Embodiment 5 of the present invention will be described below with reference to the drawings. FIG. 13 is a refrigerant circuit diagram showing a fifth embodiment of the present invention. In the figure, 1 is a compressor, 3 is a heat source side heat exchanger, 4 is a throttle device, 5 is a load side heat exchanger, and 6 is a low pressure receiver, and these are sequentially connected to form a main refrigerant circuit. Further, 101 is a temperature sensor, 103 is a pressure sensor, and 100 is a controller that calculates the circulating composition from the information of the temperature sensor and the pressure sensor, determines the opening of the expansion device, and performs control.

The operation will be described. The refrigerant is the compressor 1
Is discharged from the heat source side, condensed in the heat source side heat exchanger 3, and throttled by the expansion device 4 to be in a low temperature / low pressure two-phase state. The low-temperature low-pressure two-phase refrigerant flows into the load-side heat exchanger 5 to remove heat from the surroundings and cool, and at the same time evaporates itself and returns to the compressor 1 via the low-pressure receiver 6.

The controller 100 has a function of calculating the circulation composition α and a function of driving the expansion device 4. Circulation composition α
Is calculated from the temperature T detected by the temperature sensor and the pressure P detected by the pressure sensor. FIG. 14 is a diagram in which the composition of the refrigerant is plotted on the horizontal axis and the temperature is plotted on the vertical axis under a constant pressure.
In the figure, the saturated vapor temperature is indicated by a broken line, and the saturated liquid temperature is indicated by a one-dot chain line. From the figure, it can be seen that the composition is uniquely determined when the pressure, the temperature, and the dryness of the refrigerant are determined in the two-phase portion (including the saturated state). Therefore, in general, when the dryness of the condenser outlet refrigerant is considered to be about 0, the temperature T
The circulation composition can be obtained from the pressure P and the pressure P. The dryness of 0 indicates a saturated liquid state. The controller calculates the condensation temperature Tc from the calculated circulation composition and the value P detected by the pressure sensor 103. From the difference between the value T detected by the temperature sensor and the condensation temperature Tc, the condenser outlet supercooling degree SC is calculated from SC = Tc-T. As a result, it is possible to optimize the degree of supercooling of the refrigerant at the outlet of the condenser by repeating the same calculation as in the first embodiment, and to perform efficient operation. The aperture of the throttle is determined with SC as a target value, but it is assumed that SC when determining this and the dryness of 0 (SC = 0) in the composition estimation are different. In Examples 4 and 5, since the composition is estimated from the temperature and pressure of the portion in the refrigeration cycle that is in a saturated state, the calculation can be greatly simplified, thus simplifying the program of the controller 100 and the preset values, Not only is the cost low, but since the control is performed based on the estimated composition, the refrigeration cycle has high reliability, and a cost-effective device can be obtained.

Example 6. Embodiment 6 of the present invention will be described below with reference to the drawings. FIG. 15 is a refrigerant circuit diagram showing Embodiment 6 of the present invention. In the figure, 1 is a compressor, 3 is a heat source side heat exchanger, 11 is a high pressure receiver, 4 is a throttle device, 5 is a load side heat exchanger, and 6 is a low pressure receiver. It forms a refrigerant circuit. Further, 101 is a temperature sensor and 103 is a pressure sensor, which measures the pressure and temperature inside the high-voltage receiver. Reference numeral 100 denotes a controller that calculates the circulating composition based on the information from the temperature sensor and the pressure sensor, determines the opening of the expansion device, and controls.

The operation will be described. The refrigerant is the compressor 1
Is further discharged, condensed in the heat source side heat exchanger 3, and once enters the high pressure receiver. The liquid refrigerant flowing out from the high-pressure receiver is throttled by the throttling device 4 and becomes a low-temperature / low-pressure two-phase state. The low-temperature low-pressure two-phase refrigerant flows into the load-side heat exchanger 5 to remove heat from the surroundings and cool, and at the same time evaporates itself and returns to the compressor 1 via the low-pressure receiver 6.

The controller has a function of calculating the circulation composition α,
It has a function of driving the diaphragm device 4. The circulation composition α is calculated by the temperature T101 detected by the temperature sensor and the pressure sensor 1.
And the pressure P detected by 03. Generally, when the dryness of the refrigerant at the outlet of the condenser is considered to be about 0, the dryness also becomes 0 inside the high-pressure receiver, so that the circulating composition can be obtained from the temperature T and the pressure P. The controller calculates the condensation temperature Tc from the calculated circulation composition and the value P detected by the pressure sensor 103. From the difference between the value T detected by the temperature sensor and the condensation temperature Tc, the condenser outlet supercooling degree SC is calculated from SC = Tc-T. As a result, the degree of supercooling of the refrigerant at the outlet of the condenser can be made appropriate, and efficient operation can be performed.

Since the saturated liquid surface is always formed in the high-pressure receiver, the pressure can be detected more reliably, and the refrigeration plant with higher reliability can be obtained with high accuracy in calculating the circulation composition. Further, this high-pressure receiver may be provided anywhere between the condenser and the expansion device, but it is necessary to secure a saturated liquid level. In Examples 1 to 6, S at the outlet of the evaporator
H, or by making SC at the condenser outlet constant,
The state of the refrigerant distributed in the refrigerant circuit is proper.

That is, in the refrigerant circuit consisting of the compressor, the condenser, the expansion device, and the evaporator, a detector for detecting the pressure and temperature at the place where the operating state such as mode, start-up, load magnitude, etc. or the saturated state is detected. Then, the composition is determined by the value detected by the detector, the saturation temperature is calculated according to the composition, and the throttle opening is controlled by the controller so that the evaporator outlet SH or the condenser outlet SC reaches the target value. It is equipped with. This allows
You can drive efficiently. Furthermore, a refrigerant circuit consisting of a compressor, a condenser, a throttle device, and an evaporator, a composition calculation means, and a throttle control means are provided, and the dryness of the refrigerant at a specific position in the refrigeration circuit is assumed to be a constant value. The value α which has been set in advance according to the dryness is called, and the SH or SC at the outlet of the condenser or the evaporator is controlled to be constant based on α. This makes it possible to obtain a highly reliable and efficient refrigeration / air-conditioning device with simple control means.

Example 7. Embodiment 7 of the present invention will be described below with reference to the drawings. FIG. 16 is a refrigerant circuit diagram showing Embodiment 7 of the present invention. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is a heat source side heat exchanger, 8 is a supercooling heat exchanger, 4 is a first expansion device, 5 is a load side heat exchanger, and 6 is a low pressure receiver. Yes, these are connected in sequence to form the main refrigerant circuit. Further, the load side heat exchanger has a refrigerant circuit of two systems a and b, and the refrigerant circuit is branched between the first expansion device 4 and the heat source side heat exchanger on the main circuit. A bypass pipe leading to the low-pressure gas pipe section on the main circuit is connected via the device 7 and the supercooling heat exchanger 8. 101 is a first temperature sensor, 102 is a second temperature sensor, 103 is a first pressure sensor, 105 is a second pressure sensor, 107 is a third temperature sensor, 106 is a fourth temperature sensor, 109
Is a fifth temperature sensor. 100 calculates a circulation composition from the information of the first and second temperature sensors 101 and 102 and the first pressure sensor 103, and calculates the circulation composition and the third and fourth temperature sensors and the second pressure. It is a controller that determines the opening degree of the diaphragm device from the detection value of the sensor and performs control.

The operation will be described. During the cooling operation, the refrigerant is discharged from the compressor 1, condensed in the heat source side heat exchanger 3, and throttled by the expansion device 4 to be in a low temperature / low pressure two-phase state. This low-temperature, low-pressure two-phase refrigerant flows into the load-side heat exchanger 5 to remove heat from the surroundings and cool, and at the same time evaporate itself and pass through the four-way valve 2 and the low-pressure receiver 6 to the compressor 1. Return. Part of the refrigerant flows into the bypass pipe 200, is throttled to a low pressure by the second expansion device, and is introduced to the supercooling heat exchanger 8. The supercooling heat exchanger 8 exchanges heat between the high-pressure liquid refrigerant flowing in the main circuit and the low-temperature low-pressure two-phase refrigerant flowing in the bypass pipe 200. Therefore, the enthalpy of the refrigerant flowing through the bypass pipe 200 is transmitted to the refrigerant flowing through the main circuit, and energy loss is eliminated.

The controller has a function of calculating the circulation composition α,
It has a function of adjusting the opening degree of the expansion device 4, the operating frequency of the compressor 1, and the rotation speed of the blower 12. The calculation of the circulation composition α is performed in the following procedure. The data on the bypass circuit 200 is used as the data. First, the values T1, T2 and P1 detected by the first temperature sensor, the second temperature sensor and the first pressure sensor are fetched. Assuming a circulating composition α ₁ such that the initial value is the refrigerant filling composition, the enthalpy H1 is calculated from T1, assuming that the enthalpy of the liquid refrigerant depends only on the temperature of the refrigerant. If the enthalpy of the refrigerant at the outlet of the second expansion device 7 is equal to the enthalpy at the entrance of the second expansion device 7, T2, P1 and H1
From this, the dryness X at the outlet of the second expansion device 7 can be obtained. The circulation composition α _{2 of the} refrigerant is back-calculated from the calculation result X, T2 and P1. Until α ₁ and α ₂ are equal, for example α ₁ =
The assumption of (α ₁ + α ₂ ) / 2 and α ₁ is repeatedly calculated, and the obtained result is defined as the circulation composition α.

When the circulating composition α is obtained, the condensation temperature Tc can be obtained from P1 and α, and the evaporation temperature Te can be obtained from T1. In the controller, the target values of the condensation temperature and the evaporation temperature are set in advance, and the operating frequency of the compressor 1 and the rotation speed of the blower 12 are respectively corrected according to the deviations from the target values. Further, the opening degree of the expansion device 4 is controlled so that the difference between the values detected by the third and fourth temperature sensors 107 and 106 becomes constant. As described above, the refrigerant temperature depends on the control of the compressor or the blower, and the circulation composition depends on the valve opening. For example, in the case of multiple models, the throttle plays a role of controlling the flow rate of the refrigerant. If the liquid level inside the low-pressure receiver fluctuates due to the operation of the diaphragm, the composition fluctuates as a result. Reference numeral 109 is a fifth temperature sensor, and by making the difference between the first and fifth temperature sensors constant, the flow rate of the refrigerant in the bypass flowing through the supercooling heat exchanger is controlled and heat exchange efficiency is improved. The effect on α is that when the liquid refrigerant is bypassed from the bypass to the low pressure receiver,
The liquid refrigerant inside the low-pressure receiver increases and the composition increases.

The flow of the refrigerant during the heating operation is shown by the broken line in FIG. The refrigerant flows into the bypass pipe 200 in a two-phase state. Therefore, the circulation composition α is calculated in the following procedure. The values T1 and P1 detected by the first temperature sensor and the first pressure sensor are captured. Here, the dryness of the refrigerant flowing into the bypass pipe 200 is set to 0.1 to 0.4.
Set as a value of this degree, and this dryness X and T2 and P1
From this, the circulation composition α of the refrigerant is calculated. Here, the dryness is determined by assuming the state immediately after the throttling, that is, the isenthalpic change from the high-pressure liquid portion to the low-pressure two-phase portion. In the above, the temperature and pressure of the refrigerant after throttling are detected, but this considers that the sensor can be shared between cooling and heating, and if sharing is not considered, the composition in the bypass pipe during cooling is considered. As a matter of course, the composition may be estimated at the inlet (or outlet) of the evaporator during heating.

When the circulation composition α is obtained, the condensation temperature Tc can be obtained from P1 and α, and the evaporation temperature Te can be obtained from T1. In the controller, the target values of the condensation temperature and the evaporation temperature are set in advance, and the operating frequency of the compressor 1 and the rotation speed of the blower 12 are respectively corrected according to the deviations from the target values. Further, the opening degree of the expansion device 4 is controlled so that the difference between the condensation temperature and the value detected by the fourth temperature sensor becomes constant. Condensation temperature is determined as a function of compressor discharge pressure and composition. The evaporation temperature is determined by the temperature of the two-phase refrigerant after squeezing. Also,
The target values are, for example, a condensation temperature of 50 ° C. and an evaporation temperature of 0 ° C. Therefore, the estimation accuracy of the circulation composition is good, and efficient operation can be reliably performed. FIG. 17 shows the ratio between the temperature and the weight of the high boiling point component in the circulating composition in the refrigerant circuit. For example, when the low pressure is a constant pressure P and the temperature near the outlet of the second expansion device 7 is t, The ratio is shown assuming that the dryness is 0.25. The composition is obtained by storing such characteristics in advance.

Example 8. Embodiment 8 of the present invention will be described below with reference to the drawings. FIG. 18 is a refrigerant circuit diagram showing Embodiment 8 of the present invention. In the figure, the same parts as those of the seventh embodiment are designated by the same reference numerals and the description thereof will be omitted. A third expansion device 9 is added between the heat source side heat exchanger 3 and the supercooling heat exchanger in the configuration of the seventh embodiment in FIG.

The operation will be described. The cooling operation is the same as that of the seventh embodiment except that the opening degree of the third expansion device is fully opened, and thus the description thereof is omitted. The heating operation will be described. During the heating operation, the refrigerant is discharged from the compressor 1, condensed in the load side heat exchanger 5, and slightly throttled by the expansion device 4. The slightly throttled high pressure liquid refrigerant is throttled to a low pressure by the third expansion device 9 to become a low temperature / low pressure two-phase refrigerant. This low-temperature low-pressure two-phase refrigerant flows into the heat source side heat exchanger 3, evaporates and vaporizes, and then the four-way valve 2 and the low pressure receiver 6
Return to the compressor 1 via. Part of the refrigerant flows into the bypass pipe 200, is throttled to a low pressure by the second expansion device, and is introduced to the supercooling heat exchanger 8. Supercooling heat exchanger 8
Performs heat exchange between the high-pressure liquid refrigerant flowing in the main circuit and the low-temperature low-pressure two-phase refrigerant flowing in the bypass pipe 200. As a result, the sensor can be shared during cooling and heating.

The circulating composition is calculated in the same manner as in the cooling operation of the seventh embodiment. When the circulation composition α is obtained, the condensation temperature Tc can be obtained from P1 and α, and the evaporation temperature Te can be obtained from T1. In the controller, the target values of the condensation temperature and the evaporation temperature are set in advance, and the operating frequency of the compressor 1 and the rotation speed of the blower 12 are respectively corrected according to the deviations from the target values. Further, the opening degree of the expansion device 4 is controlled so that the difference between the condensation temperature Tc and the value T4 detected by the fourth temperature sensor is constant. The opening degree of the second expansion device 7 is controlled so that the difference between the values detected by the first and fifth temperature sensors 101 and 109 becomes constant. Therefore, in the present embodiment, by adding the throttle, it is possible to make the estimation method of the circulation composition the same in cooling and heating, and also with high accuracy,
Efficient operation can be performed.

Example 9. Embodiment 9 of the present invention will be described below with reference to the drawings. FIG. 19 is a refrigerant circuit diagram showing Embodiment 9 of the present invention. In the figure, the same parts as those of the seventh embodiment are designated by the same reference numerals, and the description thereof will be omitted. FIG. 20 shows the main pipe 210 and the bypass pipe 200 in this embodiment.
It shows the branch part of. As shown in the figure, the bypass pipe 200 is connected downward to the main pipe 210. That is, the inlet is provided at the bottom of the main pipe.

The operation will be described. The cooling operation is the same as that of the seventh embodiment, and therefore will be omitted. The flow of the refrigerant during the heating operation is shown by the broken line in FIG. During heating, the refrigerant is in a low-temperature, low-pressure gas-liquid two-phase state in the main pipe connecting the first expansion device 4 and the heat source side heat exchanger 3. At this time, the flow mode of the refrigerant may be a flow in which gas and liquid are vertically separated as shown by a broken line in FIG.
1 has a form of an annular flow that forms a liquid film on the wall of the tube as indicated by the broken line. Therefore, in either form, the liquid refrigerant of the gas-liquid two-phase state refrigerant flows into the bypass pipe. That is, the dryness of the refrigerant flowing into the bypass pipe can be zero.

The circulation composition α is calculated by the following procedure.
The values T1 and P1 detected by the first temperature sensor and the first pressure sensor are captured. Here, the dryness of the refrigerant flowing into the bypass pipe 200 is set to 0, and from the dryness X and T2 and P1, the bypass pipe 200 is set.
The composition α _L of the refrigerant flowing inside is calculated. From this α _L ,
The composition α (circulation composition) of the refrigerant flowing through the main pipe 210 is estimated.

When the circulation composition α is obtained, the condensation temperature Tc can be obtained from P1 and α, and the evaporation temperature Te can be obtained from T1. In the controller, the target values of the condensation temperature and the evaporation temperature are set in advance, and the operating frequency of the compressor 1 and the rotation speed of the blower 12 are respectively corrected according to the deviations from the target values. Further, the opening degree of the expansion device 4 is controlled so that the difference between the condensation temperature and the value detected by the fourth temperature sensor becomes constant. This is to perform VPM control that determines the rotational speed of the compressor and the gain (change amount) of the outdoor fan air volume from the high pressure (condensing temperature) and the low pressure (evaporating temperature). Therefore, the estimation accuracy of the circulation composition during heating can be improved at low cost. Although the control differs between cooling and heating, composition estimation is possible without changing the refrigerant circuit configuration. In Examples 7 to 9, a bypass pipe for flowing a liquid refrigerant is provided between the heat source side heat exchanger (condenser) and the throttle, and by utilizing the fact that the main pipe and the bypass have the same composition, the bypass pipe Α is repeatedly calculated by using the isenthalpic change before and after throttling, the condensation temperature and the evaporation temperature are calculated based on α, and the compressor, blower, etc. are controlled so as to match the target values. That is, in the refrigerant circuit including the compressor, the condenser, the expansion device, the evaporator, and the low-pressure receiver,
It is provided with a bypass pipe from between the condenser and the expansion device to the low-pressure receiver via the second device, a composition calculation means, and a controller for determining and controlling the opening of the expansion device.

Example 10. Embodiment 10 of the present invention will be described below with reference to the drawings. 22 is a refrigerant circuit diagram showing Embodiment 10 of the present invention. In the figure, the same parts as those of the seventh embodiment are designated by the same reference numerals, and the description thereof will be omitted. FIG. 23
Shows a branch portion between the main pipe 210 and the bypass pipe 200 in the present embodiment. As shown in the figure, in the vicinity of the branch portion between the bypass pipe 200 and the main pipe 210, a mesh 211 is installed upstream of the branch portion of the main pipe.

The operation will be described. The cooling operation is the same as that of the seventh embodiment, and therefore will be omitted. The flow of the refrigerant during heating is shown by the broken line in FIG. Bypass piping 2
00 and the effect of the mesh 211 installed in the vicinity of the branch portion of the main pipe 210, the refrigerant having a flow mode in which gas and liquid are separated upstream of the mesh 211 becomes a spray state after passing through the mesh. As a result, the bypass piping 200
A refrigerant having a dryness equal to the dryness of the refrigerant flowing through the main pipe 210 flows into this.

Therefore, the calculation of the circulation composition α is performed in the following procedure. The values T1 and P1 detected by the first temperature sensor 101 and the first pressure sensor 103, respectively, are loaded. Here, the dryness of the refrigerant flowing into the bypass pipe 200 is set to a value of about 0.1 to 0.4, and the dryness X
And the circulating composition α of the refrigerant is calculated from T2 and P1.

When the circulation composition α is obtained, the condensation temperature Tc can be obtained from P1 and α, and the evaporation temperature Te can be obtained from T1. In the controller, the target values of the condensation temperature and the evaporation temperature are set in advance, and the operating frequency of the compressor 1 and the rotation speed of the blower 12 are respectively corrected according to the deviations from the target values. Further, the opening degree of the expansion device 4 is controlled so that the difference between the condensation temperature and the value detected by the fourth temperature sensor 106 becomes constant. Therefore, by adding the mesh, the main pipe in the vicinity of the branch portion with the bypass pipe 200 and the dryness of the refrigerant flowing in the bypass pipe 200 are equalized during heating, and the estimation accuracy of the circulation composition during heating is improved. Then
It is possible to reliably perform efficient operation. Although the example in which the mesh is provided has been described above, it goes without saying that, for example, a weir may be provided on the peripheral wall or a moving stirring may be performed as long as it has a structure in which the gas-liquid separated refrigerant is in a spray state.

Example 11. Embodiment 11 of the present invention will be described below with reference to the drawings. 24 is a refrigerant circuit diagram showing Embodiment 11 of the present invention. In the figure, the same parts as those of the seventh embodiment are designated by the same reference numerals, and the description thereof will be omitted. In this embodiment, the information of the second temperature sensor 106 is taken into the arithmetic unit.

The operation will be described. The cooling operation is the same as that of the seventh embodiment, and thus the description thereof is omitted. Since only the operation of the arithmetic unit is different during the heating operation, the description of the operation of the main controller will be omitted. The calculation of the circulation composition α during the heating operation is performed according to the following procedure. The values T1, T2, and P1 detected by the fourth temperature sensor 106, the second temperature sensor 102, and the first pressure sensor 103, respectively, are loaded. Assuming the circulation composition α ₁ , the enthalpy H1 is calculated from T1, assuming that the enthalpy of the liquid refrigerant depends only on the temperature of the refrigerant. Assuming that the enthalpy of the refrigerant at the outlet of the second expansion device 7 is equal to the enthalpy at the entrance of the second expansion device 7, the dryness X at the exit of the second expansion device 7 can be obtained from T2, P1 and H1. This calculation result X and T2 and P
The circulation composition α _{2 of the} refrigerant is calculated back from 1. The assumption of α ₁ is repeatedly calculated until α ₁ and α ₂ are equal, and the obtained result is set as the circulation composition α.

Therefore, even during the heating operation, the composition can be accurately estimated and the operation can be performed efficiently.

Example 12. Embodiment 12 of the present invention will be described below with reference to the drawings. FIG. 25 is a refrigerant circuit diagram showing Embodiment 12 of the present invention. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is a heat source side heat exchanger, 8 is a supercooling heat exchanger, 4
Is a first expansion device, 5 is a load side heat exchanger, and 6 is a low-pressure receiver, which are sequentially connected to form a main refrigerant circuit. The load side heat exchanger has a refrigerant circuit of two systems, a and b. A refrigerant circuit is branched between the first expansion device 4 and the heat source side heat exchanger on the main circuit, and the low pressure on the main circuit is divided via the second expansion device 7 and the supercooling heat exchanger 8. The bypass pipe 200 leading to the gas pipe section is connected.
101 is a first temperature sensor, 102 is a second temperature sensor, 103 is a first pressure sensor, 105 is a second pressure sensor, 107 is a third temperature sensor, and 106 is a fourth temperature sensor. Reference numeral 110 denotes an arithmetic unit that calculates the circulation composition based on the information from the first and second temperature sensors 101 and 102 and the first pressure sensor 103. Reference numeral 111 is a composition adjuster for adjusting the composition. Reference numeral 112 determines the opening degree of the expansion device, the operating frequency of the compressor, and the fan rotation speed of the outdoor unit from the detected values of the third and fourth temperature sensors 107 and 106 and the second pressure sensor 105, and controls them. It is the main controller that performs.

The operation will be described. During the cooling operation, the refrigerant is discharged from the compressor 1, condensed in the heat source side heat exchanger 3, and throttled by the expansion device 4 to be in a low temperature / low pressure two-phase state. This low-temperature, low-pressure two-phase refrigerant flows into the load-side heat exchanger 5 to remove heat from the surroundings and cool, and at the same time evaporate itself and pass through the four-way valve 2 and the low-pressure receiver 6 to the compressor 1. Return. Part of the refrigerant flows into the bypass pipe 200, is throttled to a low pressure by the second expansion device, and is introduced to the supercooling heat exchanger 8. The supercooling heat exchanger 8 exchanges heat between the high-pressure liquid refrigerant flowing in the main circuit and the low-temperature low-pressure two-phase refrigerant flowing in the bypass pipe 200. Therefore, the enthalpy of the refrigerant flowing through the bypass pipe 200 is transmitted to the refrigerant flowing through the main circuit, and energy loss is eliminated.

The arithmetic unit has a function of calculating the circulation composition α. The calculation of the circulation composition α is performed in the following procedure. The data on the bypass circuit 200 is used as the data. First, the values T1, T2 and P1 detected by the first temperature sensor, the second temperature sensor and the first pressure sensor are fetched. Assuming the circulation composition α ₁ , the enthalpy H1 is calculated from T1, assuming that the enthalpy of the liquid refrigerant depends only on the temperature of the refrigerant. Assuming that the enthalpy of the refrigerant at the outlet of the second expansion device 7 is equal to the enthalpy at the inlet of the second expansion device 7, from T2, P1 and H1 to the second expansion device 7
The dryness X at the exit is obtained. The circulation composition α _{2 of the} refrigerant is back-calculated from the calculation result X, T2 and P1. α ₁ and α ₂
The hypothesis of α ₁ is iteratively calculated until the values are equal to each other, and the obtained result is set as the circulation composition α.

The operation of the composition regulator during the cooling operation will be described. The composition regulator operates when some of the load side heat exchangers are stopped.
The load side heat exchanger that is currently stopped is designated as 5a. The composition controller adjusts the composition according to the difference between the circulation composition α calculated by the calculation device 110 and the target circulation composition α ^* . In the composition adjusting method, first, the liquid refrigerant is stored in the low pressure receiver.
At this time, the liquid level of the low-pressure receiver rises, so that the refrigerant having a low boiling point in the circulation composition circulates in the refrigerant circuit. Here, the first expansion device 4a is closed, and the high temperature and high pressure liquid refrigerant is guided to the pipe 202a. at this point,
Since the refrigerant discharged from the compressor is rich in low boiling point components,
The refrigerant stored inside the pipe 202a is rich in low-boiling components. As a result, the composition of the refrigerant circulating in the refrigerant circuit changes from one rich in low-boiling components to one rich in high-boiling components. Here, in the comparison between the circulation composition α calculated by the calculation device 110 and the target circulation composition α ^* , when α <α ^* , the first expansion device 4a is opened, and when α> α ^* Controls to close the first expansion device 4a so that the circulation composition is balanced near the target value.

In the main controller, the condensation temperature Tc is calculated from the circulation composition α and P1 obtained by the arithmetic unit, and the evaporation temperature Te is calculated from T1.
Ask for. Further, the target values of the condensation temperature and the evaporation temperature are set in advance, and the operating frequency of the compressor 1 and the rotation speed of the blower 12 are corrected in accordance with the deviations from the target values. Further, the opening degree of the expansion device 4 is controlled so that the difference between the values detected by the third and fourth expansion devices becomes constant.
The opening degree of the second expansion device is controlled so that the difference between the values detected by the first and fifth temperature sensors is constant.

The flow of the refrigerant during the heating operation is shown by the broken line in FIG. The refrigerant flows into the bypass pipe 200 in a two-phase state. Therefore, the circulation composition α is calculated in the following procedure. The values T1 and P1 respectively detected by the first temperature sensor and the first pressure sensor are loaded into the arithmetic unit. Here, the dryness of the refrigerant flowing into the bypass pipe 200 is set to 0.
Set as a value of 1 to 0.4, and the dryness X and T2
And the circulating composition α of the refrigerant is calculated from P1.

The operation of the composition regulator during heating will be described. The composition regulator operates when some of the load side heat exchangers are stopped. The load side heat exchanger that is currently stopped is designated as 5a. The composition controller adjusts the composition according to the difference between the circulation composition α calculated by the calculation device 110 and the target circulation composition α ^* . In the composition adjusting method, first, the liquid refrigerant is stored in the low pressure receiver. To store the liquid in the low-pressure receiver, the expansion device 4 is fully opened and the compressor is activated. At this time, the liquid level of the low-pressure receiver rises, so that the refrigerant having a low boiling point in the circulation composition circulates in the refrigerant circuit. Here, the first expansion device 4a is closed and the high-temperature, high-pressure liquid refrigerant is guided to the pipe 202b. At this point, the refrigerant discharged from the compressor is rich in low-boiling components, so the refrigerant stored inside the pipe 202b is rich in low-boiling components. As a result, the composition of the refrigerant circulating in the refrigerant circuit changes from one rich in low-boiling components to one rich in high-boiling components. Here, in the comparison between the circulation composition α calculated by the calculation device 110 and the target circulation composition α ^* , when α <α ^* , the first throttle device is opened, and α>
In the case of α ^* , control is performed to close the first diaphragm device,
Try to balance the circulation composition near the target value.

In the main controller, when the circulation composition α is obtained, the condensation temperature Tc is obtained from P1 and α, and the evaporation temperature Te is obtained from T1.
Can be requested. In the controller, the target values of the condensation temperature and the evaporation temperature are set in advance, and the operating frequency of the compressor 1 and the blower 12 are set in accordance with the deviations from the target values.
Correct the rotation speed of. Further, the opening degree of the expansion device 4 is controlled so that the difference between the condensation temperature and the value detected by the fourth temperature sensor becomes constant. Therefore, the estimation accuracy of the circulation composition is good, and efficient operation can be reliably performed. When adjusting the composition, it is necessary to let the refrigerant fall asleep with the composition that is flowing at that moment. That is, when the refrigerant rich in low boiling point components is stored in the stopped indoor unit, the insufficient refrigerant evaporates from the low pressure receiver. Since the evaporated refrigerant is rich in high-boiling components, the composition changes. If the throttle of the stopped indoor unit is opened, the refrigerant having the same circulation composition will flow into the stopped indoor unit, and this effect is diminished.

Example 13 Embodiment 13 of the present invention will be described below with reference to the drawings. FIG. 26 is a refrigerant circuit diagram showing Embodiment 13 of the present invention. In the figure, the same parts as those in the twelfth embodiment are designated by the same reference numerals, and the description thereof will be omitted. Figure 2
In the twelfth embodiment of the fifth aspect, the refrigerant dryness sensor 150 is provided near the branch portion between the main pipe and the bypass pipe 200.
To add.

The operation will be described. Since the operation during cooling is the same as that of the twelfth embodiment, the description thereof will be omitted. Further, in the heating operation, the refrigerant flow, the composition controller, and the main controller have the same functions as in the twelfth embodiment, and thus the description thereof will be omitted. Therefore, only the operation of the arithmetic unit during the heating operation will be described. The calculation of the circulation composition α is performed in the following procedure. The values T1 and P1 detected by the first temperature sensor and the first pressure sensor are fetched into the arithmetic unit. Here, the branch portion of the bypass pipe 200 is made only of the liquid of the inflowing refrigerant by being installed downward. Therefore, the dryness X of the refrigerant flowing into the bypass pipe 200 is set to 0.
And the composition α ⁻ of the refrigerant flowing through the bypass pipe 200 is calculated from the dryness X and T2 and P1.
The circulation composition α of the refrigerant flowing through the main pipe is calculated from this α ⁻ and the dryness X ⁻ detected by the dryness sensor 150.

Therefore, in the present embodiment, the composition estimation accuracy is high even during heating, and efficient operation can be performed. In Examples 7 to 13, the opening degree of the second expansion device 7 is controlled so that the temperature difference between the inlet and outlet of the heat exchange section 8 provided in the bypass pipe 200 becomes a predetermined value (for example, 10 ° C). It That is, a temperature sensor provided in the bypass pipe 200, for example, a difference between temperatures detected by 101 and 109 is calculated, and feedback control such as PID control is performed according to the difference between the temperature difference and a predetermined value (for example, 10 ° C.). The correction value of the opening degree of the expansion device 7 is calculated by this, and by doing so, the refrigerant going from the bypass pipe 200 to the low-pressure receiver 6 is always in a vapor state, energy is effectively used, and the compressor 1 It also has the effect of preventing the liquid from returning. In this embodiment, a two-component system is described as the mixed refrigerant, but the same effect can be obtained in the case of a multi-component system such as a three-component system.

Example 14 Embodiment 14 of the present invention will be described below with reference to the drawings. FIG. 27 is a refrigerant circuit diagram showing Embodiment 14 of the present invention. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is a heat source side heat exchanger, 9 is a second expansion device, 1
Reference numeral 1 is a high pressure receiver, 4 is a first expansion device, 5 is a load side heat exchanger, and 6 is a low pressure receiver, and these are sequentially connected to form a main refrigerant circuit. 101 is a first temperature sensor, 102 is a second temperature sensor, 103 is a first pressure sensor, 107 is a third temperature sensor, 122 is a fourth temperature sensor, and 123 is a second pressure sensor. 108, 1
Reference numerals 09 are fifth and sixth temperature sensors, respectively. Reference numeral 110 denotes an arithmetic unit that calculates the circulation composition based on the information from the first, second, third and fourth temperature sensors and the first and second pressure sensors. Reference numeral 112 denotes a main controller that determines the opening degrees of the first and second throttle devices and controls the opening degrees.

The operation will be described. During the cooling operation, the refrigerant is discharged from the compressor 1 and condensed in the heat source side heat exchanger 3. Here, when the value of the second pressure sensor 123 is equal to or greater than a certain set value, the main controller 112 judges that
The second expansion device 9 is fully opened. The liquid refrigerant flows into the high-pressure receiver 11, and the liquid refrigerant is stored. The liquid refrigerant flowing out of the high-pressure receiver 11 is throttled by the first expansion device 4 and becomes a low-temperature / low-pressure two-phase state. This low-temperature, low-pressure two-phase refrigerant flows into the load side heat exchanger 5 to remove heat from the surroundings and cool, and at the same time evaporate itself and pass through the four-way valve 2 and the low pressure receiver 6 to the compressor 1
Return to As a result, since the liquid refrigerant does not exist in the low pressure receiver, the high boiling point component increases in the circulation composition, and the high pressure decreases. At this time, the main controller 112
Then, the first temperature sensor 101 and the fifth temperature sensor 10
8 so that the difference between the detection values of 8 is constant.
Control the opening of.

During the cooling operation, when the value of the second pressure sensor 123 is less than a certain set value, the first throttle device 4 is fully opened according to the judgment of the main controller. Heat source side heat exchanger 3
The liquid refrigerant condensed in 2 becomes a low-temperature, low-pressure two-phase state in the second expansion device 9. Since the two-phase refrigerant flows into the high-pressure receiver 11 and the liquid refrigerant flows out, the liquid refrigerant is not stored. The low-temperature, low-pressure two-phase refrigerant flowing out from the high-pressure receiver 11 flows into the load-side heat exchanger 5 to take heat from the surroundings and cool, and at the same time evaporate itself, and pass through the four-way valve 2 and the low-pressure receiver 6. , Return to compressor 1. As a result, the liquid refrigerant is stored in the low-pressure receiver, the low boiling point component is increased in the circulating composition, and the high pressure is increased.

The arithmetic unit has a function of calculating the circulation composition α. The calculation of the circulation composition α is performed in the following procedure. The values T1, T2, and P1 detected by the third temperature sensor 107, the fourth temperature sensor 122, and the second pressure sensor 123 are taken in. Assuming a circulation composition α ₁ , the enthalpy of the liquid refrigerant is T
The enthalpy H1 is calculated from 1. Assuming that the enthalpy of the refrigerant at the outlet of the second expansion device 9 is equal to the enthalpy at the entrance of the second expansion device 9, the dryness X at the exit of the first expansion device 4 can be obtained from T2, P1 and H1. The circulation composition α _{2 of the} refrigerant is back-calculated from the calculation result X, T2 and P1.
The assumption of α ₁ is repeatedly calculated until α ₁ and α ₂ are equal, and the obtained result is set as the circulation composition α.

When the circulating composition α is obtained, the main controller determines the condensing temperature Tc from P1 and α. The opening degree of the second expansion device 9 is the condensation temperature and the third temperature sensor 121.
The difference between the values detected by is controlled to be constant.

During the heating operation, the refrigerant is discharged from the compressor 1 and condensed in the load side heat exchanger 5. Here, when the value of the first pressure sensor 103 is equal to or greater than a certain set value, the first throttle device 4 is fully opened according to the judgment of the main controller. The liquid refrigerant flows into the high-pressure receiver 11, and the liquid refrigerant is stored. The liquid refrigerant flowing out from the high-pressure receiver 11 is throttled by the second expansion device 9 to be in a low temperature / low pressure two-phase state. The low-temperature low-pressure two-phase refrigerant flows into the heat source side heat exchanger 3, evaporates and vaporizes, and returns to the compressor 1 via the four-way valve 2 and the low pressure receiver 6. As a result, since the liquid refrigerant does not exist in the low pressure receiver, the high boiling point component increases in the circulation composition, and the high pressure decreases. At this time, in the main controller, the third temperature sensor 10
The opening degree of the second expansion device 9 is controlled so that the difference between the detection values of the seventh and sixth temperature sensors 109 becomes constant.

During the heating operation, when the value of the first pressure sensor 103 is less than a certain set value, the second throttle device 9 is fully opened according to the judgment of the main controller. Load side heat exchanger 5
The liquid refrigerant condensed in 1. becomes a low-temperature, low-pressure two-phase refrigerant in the first expansion device 4. Since the two-phase refrigerant flows into the high-pressure receiver 11 and the liquid refrigerant flows out, the liquid refrigerant is not stored. The low-temperature low-pressure two-phase refrigerant flowing out from the high-pressure receiver 11 flows into the heat source side heat exchanger 3 to remove heat from the surroundings and cool, and at the same time evaporate itself, and pass through the four-way valve 2 and the low-pressure receiver 6. , Return to compressor 1. As a result, the liquid refrigerant is stored in the low-pressure receiver, the low boiling point component is increased in the circulating composition, and the high pressure is increased.

The arithmetic unit has a function of calculating the circulation composition α. The calculation of the circulation composition α is performed in the following procedure. The values T1, T2, and P1 detected by the first temperature sensor 101, the second temperature sensor 102, and the first pressure sensor 103, respectively, are loaded. Assuming a circulation composition α ₁ , the enthalpy of the liquid refrigerant is T
The enthalpy H1 is calculated from 1. Assuming that the enthalpy of the refrigerant at the outlet of the first expansion device 4 is equal to the enthalpy at the inlet of the first expansion device 4, the dryness X at the exit of the first expansion device 4 can be obtained from T2, P1 and H1. The circulation composition α _{2 of the} refrigerant is back-calculated from the calculation result X, T2 and P1.
The assumption of α ₁ is repeatedly calculated until α ₁ and α ₂ are equal, and the obtained result is set as the circulation composition α.

When the circulation composition α is obtained, the main controller obtains the condensing temperature Tc from P1 and α. The opening degree of the first expansion device 4 is the condensation temperature and the first temperature sensor 101.
The difference between the values detected by is controlled to be constant. Therefore, the estimation accuracy of the circulation composition is good, the high pressure is properly controlled, and the efficient operation can be surely performed.

Example 15. Embodiment 15 of the present invention will be described below with reference to the drawings. FIG. 28 is a refrigerant circuit diagram showing Embodiment 15 of the present invention. In the figure, 1 is a compressor, 2 is a four-way valve, 3 is a heat source side heat exchanger, 9 is a second expansion device, 1
Reference numeral 1 is a high pressure receiver, 4 is a first expansion device, 5 is a load side heat exchanger, and 6 is a low pressure receiver, and these are sequentially connected to form a main refrigerant circuit. The load side heat exchanger has a refrigerant circuit of two systems, a and b. Reference numeral 204 is a bypass pipe from the high-voltage receiver 11 to the low-voltage receiver via the third expansion device 16. 101 is a first temperature sensor, 102 is a second temperature sensor, 103 is a first pressure sensor, 105 is a second pressure sensor, 107 is a fourth temperature sensor, 106 is a third temperature sensor, and 108 is A sixth temperature sensor 109 is a fifth temperature sensor. Reference numeral 110 denotes a computing device that computes the circulation composition based on the information from the first and second temperature sensors and the first pressure sensor. 1
11 is, depending on the difference between the circulation composition and the target circulation composition,
It is a composition controller that opens and closes the third expansion device. 112
Determines the opening of the expansion device, the operating frequency of the compressor, and the fan speed of the outdoor unit from the detected values of the third, fourth, fifth and sixth temperature sensors and the second pressure sensor, and controls them. It is the main controller that does.

The operation will be described. During the cooling operation, the refrigerant is discharged from the compressor 1 and condensed in the heat source side heat exchanger 3. Here, when the device 9 is fully opened, the high-voltage receiver 1
The liquid refrigerant flows into 1 and the liquid refrigerant is stored. The liquid refrigerant flowing out of the high-pressure receiver 11 is throttled by the first expansion device 4 and becomes a low-temperature / low-pressure two-phase state.
This low-temperature, low-pressure two-phase refrigerant flows into the load side heat exchanger 5 to remove heat from the surroundings and cool, and at the same time evaporate itself and pass through the four-way valve 2 and the low pressure receiver 6 to the compressor 1
Return to

The arithmetic unit calculates the circulation composition α. The data on the bypass circuit 204 is used as the data.
First, the first temperature sensor 101 and the second temperature sensor 10
2 and the value T detected by the first pressure sensor 103, respectively.
Take in 1, T2 and P1. Assuming the circulation composition α ₁ , the enthalpy H1 is calculated from T1, assuming that the enthalpy of the liquid refrigerant depends only on the temperature of the refrigerant. The enthalpy of the refrigerant at the outlet of the second expansion device 7 is the third expansion device 16
If it is equal to the enthalpy of the inlet, the dryness X at the outlet of the second expansion device 9 can be obtained from T2, P1 and H1. From the calculation result X, T2 and P1, the refrigerant circulation composition α
Calculate ₂ backwards. The assumption of α ₁ is repeatedly calculated until α ₁ and α ₂ are equal, and the obtained result is set as the circulation composition α.

The composition controller 111 adjusts the composition according to the difference between the circulation composition α calculated by the calculation device 110 and the target circulation composition α ^* . When the relationship between α and α ^* is α <α ^* , the third diaphragm device 16 is opened according to each difference α−α ^* . The liquid refrigerant in the high-pressure receiver 11 is the low-pressure receiver 6
Move on to. As a result, in the circulating composition, the proportion of low boiling point components increases and the circulating composition α increases. When α> α ^* , the third diaphragm device 16 is closed according to each difference α−α ^* . The liquid refrigerant in the low-pressure receiver 6 is the high-pressure receiver 1
Move to 1. As a result, in the circulating composition, the proportion of high-boiling components increases and the circulating composition α decreases.

When the circulation composition α is obtained, the condensation temperature Tc can be obtained from P1 and α, and the evaporation temperature Te can be obtained from T1. In the controller, the target values of the condensation temperature and the evaporation temperature are set in advance, and the operating frequency of the compressor 1 and the rotation speed of the blower 12 are respectively corrected according to the deviations from the target values. The opening of the expansion device 4 is determined so that the difference between the values detected by the third and fourth temperature sensors is constant.

In the heating operation, the refrigerant is discharged from the compressor 1 and condensed in the load side heat exchanger 5. The liquid refrigerant is slightly squeezed by the first device 4, then flows into the high-pressure receiver 11 and is stored therein. The liquid refrigerant flowing out from the high-pressure receiver 11 is throttled by the second expansion device 9 to be in a low temperature / low pressure two-phase state. This low-temperature, low-pressure two-phase refrigerant flows into the load-side heat exchanger 5 to remove heat from the surroundings and cool, and at the same time evaporate itself and pass through the four-way valve 2 and the low-pressure receiver 6 to the compressor 1. Return.

The functions of the arithmetic unit and the composition adjuster are the same as those in the case of cooling, so the description thereof will be omitted. When the circulation composition α is obtained,
From the value P2 and α detected by the second pressure detector, the condensation temperature T
c, the evaporation temperature Te can be obtained from the value T1 detected by the first temperature detector 101. In the controller, the target values of the condensation temperature and the evaporation temperature are set in advance, and the operating frequency of the compressor 1 and the rotation speed of the blower 12 are respectively corrected according to the deviations from the target values. The opening of the expansion device 4 is determined so that the difference between the condensation temperature Tc and the value detected by the second temperature sensor is constant. The opening of the expansion device 9 is determined so that the difference between the values detected by the fifth and sixth temperature sensors is constant. Therefore, in the present embodiment, efficient operation can be realized by accurately detecting the circulation composition and adjusting the composition.

Example 16. Embodiment 16 of the present invention will be described below with reference to the drawings. FIG. 29 is a refrigerant circuit diagram showing Embodiment 16 of the present invention. In the figure, the same parts as those of the fifteenth embodiment are designated by the same reference numerals and the description thereof will be omitted. Figure 2
8, the pipe between the second expansion device 9 and the high-pressure receiver 11 and the pipe between the high-pressure receiver 11 and the first expansion device 4, and between the third expansion device 16 and the low-pressure receiver 6. The subcooling heat exchanger 17 for exchanging heat with the pipe is used.

The operation will be described. The flow of the refrigerant, the operation of the arithmetic unit, the composition adjuster, and the controller are the same as those in the fifteenth embodiment, and therefore the description thereof will be omitted. The supercooling heat exchanger 17 exchanges heat between the high-pressure liquid refrigerant flowing in the main circuit and the low-temperature low-pressure two-phase refrigerant flowing in the bypass pipe 204. Therefore, the enthalpy of the refrigerant flowing through the bypass pipe 204 is transmitted to the refrigerant flowing through the main circuit, energy loss is eliminated, and efficient operation is performed.

Example 17: Embodiment 17 of the present invention will be described below with reference to the drawings. FIG. 30 is a refrigerant circuit diagram showing Embodiment 17 of the present invention. In the figure, the same parts as those of the fifteenth embodiment are designated by the same reference numerals and the description thereof will be omitted. Figure 2
8 in Example 15, bypass pipe 2 bypassing compressor 1 discharge pipe and low-pressure receiver 6 suction pipe
05 and the bypass pipe 205 on the switchgear 18
Is added.

The operation will be described. The flow of the refrigerant, the operation of the arithmetic unit, the composition adjuster, and the controller are the same as those in the fifteenth embodiment, and therefore the description thereof will be omitted. When the liquid refrigerant in the low-pressure receiver 6 is quickly evaporated and stored in the high-pressure receiver 11, the opening / closing mechanism 18 is opened, and the high-temperature refrigerant gas discharged from the compressor is guided to the low-pressure receiver 6 and evaporated. Therefore, even if the high pressure rises abnormally, the high pressure can be quickly suppressed.

Example 18. Embodiment 18 of the present invention will be described below with reference to the drawings. FIG. 31 is a refrigerant circuit diagram showing Embodiment 18 of the present invention. In the figure, the same parts as those of the fifteenth embodiment are designated by the same reference numerals and the description thereof will be omitted. Figure 2
Bypass pipe 20 for bypassing the discharge pipe of the compressor 1 and the inside of the low-pressure receiver 6 in the embodiment 15 of No. 8
The switchgear 18 is added on the bypass pipe 205 and the bypass pipe 205.

The operation will be described. The flow of the refrigerant, the operation of the arithmetic unit, the composition adjuster, and the controller are the same as those in the fifteenth embodiment, and therefore the description thereof will be omitted. When the liquid refrigerant in the low-pressure receiver 6 is quickly evaporated and stored in the high-pressure receiver 11, the opening / closing mechanism 18 is opened to guide the high-temperature refrigerant gas discharged from the compressor into the low-pressure receiver 6 so that the liquid inside the low-pressure receiver 6 is discharged. Evaporate the refrigerant effectively. Therefore, even if the high pressure rises abnormally, the high pressure can be quickly suppressed.

Example 19 Embodiment 19 of the present invention will be described below with reference to the drawings. 32 is a refrigerant circuit diagram showing Embodiment 19 of the present invention. In the figure, the same parts as those of the fifteenth embodiment are designated by the same reference numerals and the description thereof will be omitted. Figure 2
In the fifteenth embodiment, the open / close mechanism 22 is provided between the high-voltage receiver 11 and the first expansion device 4, and the high-voltage receiver 1
A bypass pipe 206 that bypasses the opening / closing mechanism 24 and the opening / closing mechanism 22 and connects the opening / closing mechanism 21 and the first subcooling heat exchanger 25 between the first and second expansion devices 9 and the opening / closing mechanism 24.
Bypassing the open / close mechanism 23 and the second subcooling heat exchanger 2
6 and a bypass pipe 207 communicating with each other, and the first and second subcooling heat exchangers are built in the low-pressure receiver.

The operation will be described. The flow of the refrigerant, the operation of the arithmetic unit, the composition adjuster, and the controller are the same as those in the fifteenth embodiment, and therefore the description thereof will be omitted. During the cooling operation, the liquid refrigerant in the low-pressure receiver 6 is quickly evaporated, and the liquid refrigerant is supplied to the high-pressure receiver 11
When storing in the bypass pipes 2, the opening / closing mechanisms 21, 24 are opened, the opening / closing mechanisms 22, 23 are closed, and the high-pressure liquid refrigerant is
Cycle to 06. As a result, the liquid refrigerant inside the low-pressure receiver is effectively evaporated, and the latent heat of evaporation when the liquid refrigerant evaporates inside the low-pressure receiver is absorbed as the enthalpy of the liquid refrigerant in the main circuit to improve efficiency. During the heating operation, when the liquid refrigerant in the low-pressure receiver 6 is quickly evaporated and the liquid refrigerant is stored in the high-pressure receiver 11, the opening / closing mechanisms 22 and 23 are opened, the opening / closing mechanisms 21 and 24 are closed, and the high-pressure liquid refrigerant is It is circulated to the bypass pipe 207. As a result, the liquid refrigerant inside the low-pressure receiver is effectively evaporated. Therefore, in this embodiment, the same effects as those of the sixteenth and seventeenth embodiments can be obtained, and the efficiency during the cooling operation is improved.

Example 20. Embodiment 20 of the present invention will be described below with reference to the drawings. FIG. 33 is a refrigerant circuit diagram showing Embodiment 20 of the present invention. In the figure, the same parts as those of the fifteenth embodiment are designated by the same reference numerals and the description thereof will be omitted. Figure 2
In Example 15 in Example 8, the inside of the low-pressure receiver is divided, and a portion for storing the liquid refrigerant and a portion for the buffer that does not normally store the liquid and prevents a temporary liquid return to the compressor are provided. The height of the pipe opening is made higher than the height of the partition that divides the inside of the low-voltage receiver.

The operation will be described. The flow of the refrigerant, the operation of the arithmetic unit, the composition adjuster, and the controller are the same as those in the fifteenth embodiment, and therefore the description thereof will be omitted. Normally, since a part that stores excess refrigerant and a buffer part that prevents temporary liquid return to the compressor are provided, liquid return to the compressor is prevented during unsteady operation during composition adjustment, etc. Improve sex.

[0152]

Since the present invention is constructed as described above, the present invention has the following effects.

The present invention according to claim 1 always maintains the composition of the non-azeotropic mixed refrigerant suitable for the operating state, has high reliability,
It is possible to obtain a circulation system that can constantly exert its ability.

According to the second aspect of the present invention, the circulation composition suitable for the operating condition can be maintained by setting the opening degree of the expansion device, and the efficient operation can be performed by the simple control.

According to the third aspect of the present invention, the operation of the refrigerant circulation system can be controlled based on the selected circulation composition, and the efficient operation can always be performed.

According to the present invention of claim 4, the refrigerant circulation system can be controlled by judging the operating state, and stable operation can always be performed.

According to the fifth aspect of the present invention, the refrigerant circulation system is operated according to the target value of the evaporator outlet superheat degree or the condenser outlet supercooling degree.

The present invention according to claim 6 simplifies the control and improves the cooling and heating efficiency by changing the control parameters of the refrigerant circulation system at the time of cooling and at the time of heating. You can

The present invention according to claim 7 simplifies the control and changes the efficiency by changing the control parameters of the refrigerant circulation system according to the operating capacity of the compressor during cooling, during heating. Good driving can be surely performed.

According to the eighth aspect of the present invention, the start-up characteristics can be improved by changing the control parameters of the refrigerant circulation system and performing the control depending on the time from the start of the compressor.

According to the present invention of claim 9, it is possible to obtain the control capable of efficiently following the change in the operating state.

According to the tenth aspect of the present invention, the target value of the refrigerating cycle is calculated from the composition of the estimated composition of the refrigerant circulating in the refrigerant circuit (hereinafter referred to as the circulation composition), and the composition adjusting means circulates the target value. Adjust the composition to the target circulation composition,
It is possible to perform efficient operation by performing control according to the circulation composition.

The present invention according to claim 11 detects the temperature and pressure at a place where the refrigerant is saturated, obtains the composition of the refrigerant from these values, and changes the set value of the refrigeration cycle control according to this composition. Since it is controlled, the calculation becomes easy,
It is possible to obtain a highly reliable device with an inexpensive device.

According to the twelfth aspect of the present invention, of the heat source side heat exchanger and the load side heat exchanger, the pressure and temperature of the refrigerant are detected at the heat exchanger outlet serving as an evaporator, and the detected pressure and temperature are detected. The controllability of the refrigeration cycle is improved by an inexpensive device by calculating the circulation composition and controlling the refrigeration cycle.

According to the thirteenth aspect of the present invention, of the heat source side heat exchanger and the load side heat exchanger, the refrigerant pressure and temperature are detected at the heat exchanger outlet serving as a condenser, and the detected pressure and temperature are detected. The controllability of the refrigeration cycle is improved by an inexpensive device by calculating the circulation composition and controlling the refrigeration cycle.

According to the fourteenth aspect of the present invention, the pressure and temperature of the refrigerant inside the high-pressure receiver in which the saturated liquid surface exists is detected,
Since a highly accurate circulation composition is calculated by the detected pressure and temperature and the refrigeration cycle is controlled, a highly reliable refrigeration cycle can be obtained.

According to the fifteenth aspect of the present invention, the saturation temperature of the refrigerant gas is calculated according to the estimated or calculated composition of the refrigerant circulating in the refrigerant circuit, and the evaporator outlet superheat degree,
Alternatively, since the opening degree of the expansion device is changed so that the degree of supercooling at the outlet of the condenser becomes a predetermined value, efficient operation becomes possible.

The present invention according to claim 16 branches from the refrigerant circuit between the condenser and the first expansion device, and connects to the low-pressure gas pipe via the second expansion device and the supercooling heat exchanger. By-pass pipe, temperature detection means for detecting the refrigerant temperature at the outlet of the second expansion device, pressure detection means for detecting the refrigerant temperature at the outlet of the second expansion device, by the detection value of the temperature detection means and the pressure detection means By calculating the composition of the refrigerant circulating in the refrigerant circuit, changing the setting value of the refrigeration cycle control according to the composition calculation value, and controlling the refrigeration cycle, the estimation accuracy of the circulation composition is improved, The cycle can be properly controlled.

According to the seventeenth aspect of the present invention, a third expansion device is provided between the condenser and the subcooling heat exchanger, and the vicinity of the bypass pipe inlet is in a liquid state during cooling and heating. It is possible to improve the estimation accuracy of the circulation composition in cooling and heating.

In the eighteenth aspect of the present invention, the bypass pipe is provided at the lower part of the main pipe, the liquid is always introduced into the bypass pipe, and the estimation accuracy of the circulation composition during heating can be improved at low cost.

According to the nineteenth aspect of the present invention, a refrigerant agitator is provided upstream of the main pipe near the bypass pipe branch to improve the accuracy of estimating the circulation composition during heating.

The present invention according to claim 20 provides a load side heat exchanger in which the circulating composition control means is stopped, and when the composition is adjusted, refrigerant is stored in the stopped load side heat exchanger or By releasing, composition can be adjusted and highly accurate cycle control can be realized.

According to the twenty-first aspect of the present invention, during the cooling operation, the detected value of the temperature between the load side heat exchanger and the first expansion device and the temperature between the first expansion device and the high pressure receiver are detected. The circulating composition is calculated by the calculation device from the detected value and the detected value of the pressure between the load side heat exchanger and the first expansion device. During heating operation, the detected value of the temperature between the heat source side heat exchanger and the second expansion device, the detected value of the temperature between the second expansion device and the high-pressure receiver, the heat source side heat exchanger and the second The circulation composition is calculated by the calculation device from the detected value of the pressure between the expansion devices. Furthermore,
In the main controller, the opening degrees of the first and second expansion devices are calculated, and control is performed according to the composition, so that the refrigeration cycle is properly controlled, and therefore efficient operation can be performed.

According to the twenty-second aspect of the present invention, the temperature and pressure are detected on the bypass pipe connecting the high pressure receiver and the low pressure receiver, and the circulation composition is calculated by the calculation device from the detected values. The composition adjuster determines the opening degree of the third expansion device so that the calculated circulation composition becomes the target circulation composition. In the main controller, depending on the calculated circulation composition,
The rotation speed of the compressor, the rotation speed of the fan of the heat source side heat exchanger, and the opening degree of the expansion device are determined. Therefore, the composition can be calculated by the same sensor regardless of cooling and heating, and the circulation composition can be controlled to a target value, and even if the circulation composition changes, control according to the circulation composition is possible.

The present invention according to claim 23 provides a subcooling heat exchanger for exchanging heat between the main pipe before and after the high-pressure receiver and the pipe between the third expansion device and the low-pressure receiver, and by exchanging heat, The enthalpy of the refrigerant flowing through the bypass pipe can be transmitted to the refrigerant flowing through the main circuit, energy loss can be prevented, and efficient operation can be performed.

According to the twenty-fourth aspect of the present invention, a bypass pipe connecting the compressor discharge side pipe and the suction side pipe of the low pressure receiver is provided, and the liquid refrigerant inside the low pressure receiver is discharged from the compressor at a high temperature. Evaporate quickly with gas,
The time taken for the refrigerant liquid to move to the high pressure receiver can be shortened.

The present invention according to claim 25 provides a first opening / closing mechanism installed between the high voltage receiver and the first diaphragm device, and a second opening / closing mechanism installed between the high voltage receiver and the second diaphragm device. And a bypass pipe that bypasses the first opening / closing mechanism and connects the third opening / closing mechanism to the first subcooling heat exchanger, bypasses the second opening / closing mechanism, and connects the fourth opening / closing mechanism and the second opening / closing mechanism. By providing a bypass pipe that communicates the subcooling heat exchanger and incorporating the first and second subcooling heat exchangers in the low-pressure receiver, the liquid refrigerant inside the low-pressure receiver can be quickly transferred by the high-pressure and high-temperature liquid pipes. To reduce the time it takes for the refrigerant liquid to transfer to the high-pressure receiver, and to transfer the latent heat of vaporization when the refrigerant liquid evaporates inside the low-pressure receiver to the refrigerant flowing through the main circuit to improve energy efficiency. it can.

According to the twenty-sixth aspect of the present invention, the low-pressure receiver is divided, a portion for storing the liquid refrigerant and a buffer portion for preventing temporary liquid return to the compressor are provided, and liquid return to the compressor is prevented. And reliability can be improved.

According to a twenty-seventh aspect of the present invention, a compressor, a four-way valve, a condenser, a subcooling heat exchanger, a first expansion device, an evaporator and a low pressure receiver are sequentially connected, and the condenser and the first expansion device are connected. Temperature that detects the refrigerant temperature at the evaporator inlet in a refrigeration cycle that branches from the refrigerant circuit between the devices and has a bypass pipe connected to the low-pressure gas pipe via the second expansion device and the supercooling heat exchanger Detection means, pressure detection means for detecting the refrigerant pressure at the evaporator inlet, dryness detection means for detecting the dryness of the refrigerant at the evaporator inlet, temperature detection means, pressure detection means and detection values of the dryness detection means Thus, the composition of the refrigerant circulating in the refrigerant circuit can be calculated, the composition can be adjusted by the composition adjusting means so as to obtain the target composition, and more accurate cycle control can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a relationship between temperature and circulation composition of a non-azeotropic mixed refrigerant according to Example 1 of the present invention.

FIG. 3 is a flowchart showing an operation of the controller according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a relationship between a liquid level and a circulating composition of a low pressure receiver according to a second embodiment of the present invention.

FIG. 6 is a flowchart showing the operation of the controller according to the second embodiment of the present invention.

FIG. 7 is an explanatory diagram showing the relationship between the operating frequency and the circulation composition according to the second embodiment of the present invention.

FIG. 8 is a flowchart showing another operation according to the second embodiment of the present invention.

FIG. 9 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to a third embodiment of the present invention.

FIG. 10 is an explanatory diagram showing the relationship between the time from the start of the compressor and the liquid level of the low pressure receiver according to the third embodiment of the present invention.

FIG. 11 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to Embodiment 4 of the present invention.

FIG. 12 is an explanatory diagram showing the relationship between the temperature and the circulation composition of the non-azeotropic mixed refrigerant according to Example 4 of the present invention.

FIG. 13 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to a fifth embodiment of the present invention.

FIG. 14 is an explanatory diagram showing the relationship between the temperature of the non-azeotropic mixed refrigerant and the circulating composition according to Example 5 of the present invention.

FIG. 15 is a configuration diagram showing a refrigerant circuit of a refrigeration / air-conditioning apparatus according to Embodiment 6 of the present invention.

FIG. 16 is a configuration diagram showing a refrigerant circuit of a refrigeration / air-conditioning apparatus according to Embodiment 7 of the present invention.

FIG. 17 is an explanatory diagram showing the relationship between the temperature of the non-azeotropic mixed refrigerant and the circulating composition according to Example 7 of the present invention.

FIG. 18 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to Embodiment 8 of the present invention.

FIG. 19 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to Embodiment 9 of the present invention.

FIG. 20 is a detailed view of a bypass pipe branching unit according to a ninth embodiment of the present invention.

FIG. 21 is a detailed view of a bypass pipe branching portion according to the ninth embodiment of the present invention.

FIG. 22 is a configuration diagram showing a refrigerant circuit of a refrigeration / air-conditioning apparatus according to Embodiment 10 of the present invention.

FIG. 23 is a detailed view of the bypass pipe branching unit according to the tenth embodiment of the present invention.

FIG. 24 is a configuration diagram showing a refrigerant circuit of a refrigeration / air-conditioning apparatus according to Embodiment 11 of the present invention.

FIG. 25 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to Embodiment 12 of the present invention.

FIG. 26 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to Embodiment 13 of the present invention.

FIG. 27 is a configuration diagram showing a refrigerant circuit of a refrigeration / air-conditioning apparatus according to Embodiment 14 of the present invention.

FIG. 28 is a configuration diagram showing a refrigerant circuit of a refrigeration / air-conditioning apparatus according to Embodiment 15 of the present invention.

FIG. 29 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to Embodiment 16 of the present invention.

FIG. 30 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to Embodiment 17 of the present invention.

FIG. 31 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to Embodiment 18 of the present invention.

FIG. 32 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus of Embodiment 19 of the present invention.

FIG. 33 is a configuration diagram showing a refrigerant circuit of a refrigerating / air-conditioning apparatus according to Embodiment 20 of the present invention.

FIG. 34 is a configuration diagram showing a conventional refrigeration / air-conditioning apparatus using a non-azeotropic mixed refrigerant.

[Explanation of symbols]

1 compressor, 2 4-way valve, 3 heat source side heat exchanger, 4 throttling device, 5 load side heat exchanger, 6 low pressure receiver, 7
Expansion device, 8 supercooling heat exchanger, 9 expansion device, 11
High-pressure receiver, 16 expansion device, 17 supercooling heat exchanger, 18 opening / closing mechanism, 20 blower 21, 22, 2
3,24 Opening / closing mechanism, 25,26 Supercooling heat exchanger, 1
00 controller, 101 temperature sensor, 102 temperature sensor, 103 pressure sensor, 105 pressure sensor, 106
Temperature sensor, 107 temperature sensor, 108 temperature sensor, 109 temperature sensor, 110 arithmetic unit, 111
Composition regulator, 112 main controller, 122 temperature sensor, 123 pressure sensor.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshihiro Sumida 8-1-1 Tsukaguchihonmachi, Amagasaki City Mitsubishi Electric Corporation Central Research Laboratory

Claims (27)

[Claims] 1. A refrigerant circulation system in which a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger and a low pressure receiver are sequentially connected to circulate a non-azeotropic mixed refrigerant in which several refrigerants are mixed, Operation determination means for determining the operating state of each operation such as the flow direction of the refrigerant in the circulation system, the elapsed time from startup, the load amount, etc., and a storage means for storing the composition state of the refrigerant preset for each operating state. And a refrigerant composition selection means for selecting a composition state of the refrigerant from the storage means based on the operation state determined by the operation determination means, and a refrigerant circulation system for circulating the refrigerant circulation system to the composition state of the refrigerant selected by the refrigerant composition selection means. A refrigerant circulation system comprising: a refrigerant composition setting means for changing the composition of the refrigerant. 2. The refrigerant circulation system according to claim 1, wherein the refrigerant composition setting means for changing the composition of the refrigerant is an opening degree setting means of the expansion device. 3. The control means for determining a set value for controlling the operation of the refrigerant circulation system on the basis of the composition state of the refrigerant selected by the refrigerant circulation composition selection means. Refrigerant circulation system. 4. A refrigerant circulation system in which a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger and a low pressure receiver are sequentially connected to circulate a non-azeotropic mixed refrigerant in which several refrigerants are mixed, Based on the operation judging means for judging the state of each operation of the circulation system and the operation state judged by this operation judging means, the control for changing the set value of the operation control of the refrigerant circulation system to control the refrigerant circulation system A refrigerant circulation system comprising: 5. A target value of at least one of an evaporator superheat degree and a condenser outlet supercool degree is set as a set value for controlling the operation of the refrigerant circulation system, and control is performed according to this target value. The refrigerant circulation system according to claim 3 or 4, characterized in that. 6. A refrigerant circulation system in which a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger and a low pressure receiver are sequentially connected to circulate a non-azeotropic mixed refrigerant in which several refrigerants are mixed, A refrigerant circulation system comprising: a control unit that changes a set value of control of the refrigerant circulation system between heating and heating to control operation of the refrigerant circulation system. 7. A refrigerant circulation system in which a compressor, a heat source side heat exchanger, a throttle device, a load side heat exchanger and a low pressure receiver are sequentially connected to circulate a non-azeotropic mixed refrigerant in which several refrigerants are mixed, A refrigerant circulation system characterized by comprising control means for changing a set value of control of the refrigerant circulation system depending on time, heating, and operating capacity of the compressor, and controlling operation of the refrigerant circulation system. 8. A refrigerant circulation system in which a compressor, a heat source side heat exchanger, an expansion device, a load side heat exchanger and a low pressure receiver are sequentially connected to circulate a non-azeotropic mixed refrigerant in which several refrigerants are mixed, A refrigerant circulation system comprising: a control unit that changes a control set value of the refrigerant circulation system according to the time from the start of the machine and controls the operation of the refrigerant circulation system. 9. The control means for changing the set value of the control of the refrigerant circulation system every predetermined time period or each time a large change in the operating state is provided. 7. The refrigerant circulation system according to 7 or 8. 10. A compressor, a heat source side heat exchanger, a throttle device,
A load side heat exchanger and a low-pressure receiver are sequentially connected, and in a refrigeration cycle using a non-azeotropic mixed refrigerant in which several kinds of refrigerant are mixed, a mechanism for estimating the composition of the refrigerant circulating in the refrigerant circuit, and the estimated refrigerant A refrigerating / air-conditioning apparatus comprising: a controller for changing and controlling a set value for control of a refrigeration cycle and a composition of a refrigerant circulating in a refrigerant circuit according to a composition. 11. A compressor, a heat source side heat exchanger, a throttle device,
The load side heat exchanger and the low-pressure receiver are sequentially connected, and in a refrigeration cycle using a non-azeotropic mixed refrigerant in which several types of refrigerant are mixed, the heat source side heat exchanger or the load side heat exchanger is provided near the outlet, Temperature detection means and pressure detection means for detecting the temperature and pressure of the place where the refrigerant is saturated, the detection value of the temperature detection means and the pressure detection means, the composition of the refrigerant circulating in the refrigerant circuit is calculated, A refrigerating / air-conditioning apparatus comprising: a controller that changes a set value for controlling a refrigerating cycle according to the calculated composition value and controls the refrigerating cycle. 12. A temperature detecting means for detecting a refrigerant temperature at a heat exchanger outlet serving as an evaporator of the heat source side heat exchanger and the load side heat exchanger, and a pressure detecting means for detecting a refrigerant pressure at the evaporator outlet. The refrigeration / air-conditioning apparatus according to claim 11, further comprising: 13. A pressure detecting means for detecting a refrigerant pressure at a heat exchanger outlet of a heat source side heat exchanger and a load side heat exchanger, the temperature detecting means for detecting a refrigerant temperature at the condenser outlet. The refrigeration / air-conditioning apparatus according to claim 11, further comprising: 14. A refrigeration cycle in which a compressor, a heat source side heat exchanger, a high pressure receiver, a throttle device, and a load side heat exchanger are sequentially connected, and a non-azeotropic mixed refrigerant in which several refrigerants are mixed is used, The temperature detection means for detecting the refrigerant temperature, the pressure detection means for detecting the refrigerant pressure inside the high-pressure receiver, the detection value of the temperature detection means and the pressure detection means, the composition of the refrigerant circulating in the refrigerant circuit. A refrigerating / air-conditioning apparatus comprising: a controller for performing a calculation and changing a set value of the refrigerating cycle control according to the calculated composition value to control the refrigerating cycle. 15. The saturation temperature of the refrigerant gas is calculated according to the estimated or calculated composition of the refrigerant circulating in the refrigerant circuit, and the evaporator outlet superheat degree or the condenser outlet supercooling degree becomes a predetermined value. 15. A refrigeration / air-conditioning system according to claim 10, 11 or 14, further comprising: a diaphragm device for changing the opening degree. 16. A non-coexistence system in which a compressor, a four-way valve, a heat source side heat exchanger, a supercooling heat exchanger, a first expansion device, a load side heat exchanger and a low pressure receiver are sequentially connected to mix several refrigerants. In the refrigeration cycle using a boiling mixed refrigerant, branched from the refrigerant circuit between the heat source side heat exchanger and the first expansion device,
Through the second expansion device and the supercooling heat exchanger, a bypass pipe connected to the low-pressure gas pipe, a first temperature detection means for detecting the refrigerant temperature of the second expansion device inlet,
Second temperature detecting means for detecting the refrigerant temperature at the outlet of the second expansion device, pressure detecting means for detecting the refrigerant pressure at the outlet of the second expansion device, and the first and second temperature detecting means. A composition calculation device for calculating the composition of the refrigerant circulating in the refrigerant circuit by the detection value of the pressure detection means, and changing the set value of the refrigeration cycle control according to the composition calculation value to control the refrigeration cycle. A refrigeration / air-conditioning system, which is provided with a main controller. 17. A third expansion device is provided between the heat source side heat exchanger and the subcooling heat exchanger.
Refrigeration / air-conditioning system according to 6. 18. The refrigerating / air-conditioning apparatus according to claim 16, wherein the bypass piping inlet is provided at a lower portion of the main piping. 19. A refrigerant agitator is provided upstream of the main pipe near the branch of the bypass.
Refrigeration / air conditioning system as described. 20. A plurality of load side heat exchangers are provided, and
The refrigerating / air-conditioning apparatus according to claim 16, wherein the refrigerant pipe of the stopped heat exchanger on the load side is used as the composition adjusting means. 21. A compressor, a four-way valve, a heat source side heat exchanger, a second expansion device, a high pressure receiver, a first expansion device, a load side heat exchanger, a low pressure receiver, etc., and mixes several refrigerants. In the refrigeration cycle using the non-azeotropic mixed refrigerant, the first temperature detecting means for detecting the temperature between the load side heat exchanger and the first expansion device, and between the first expansion device and the high pressure receiver. Second temperature detecting means for detecting the temperature,
Third temperature detection means for detecting the temperature between the heat source side heat exchanger and the second expansion device, and a fourth temperature detection means for detecting the temperature between the second expansion device and the high-pressure receiver, Fifth temperature detecting means for detecting temperature between the four-way valve and the load side heat exchanger, and sixth temperature detecting means for detecting temperature between the four-way valve and the heat source side heat exchanger, A first pressure detecting means for detecting pressure between the load side heat exchanger and the first expansion device, and a second pressure for detecting pressure between the heat source side heat exchanger and the second expansion device. Refrigeration characterized by comprising a detection means, a computing device for computing the composition of the refrigerant circulating in the refrigerant circuit, and a main controller for computing and controlling the openings of the first and second expansion devices. -Air conditioner. 22. A compressor, a four-way valve, a heat source side heat exchanger, a second expansion device, a high pressure receiver, a first expansion device, a load side heat exchanger, a low pressure receiver, etc., and mixes several refrigerants. In a refrigeration cycle using the non-azeotropic mixed refrigerant, a bypass pipe connecting the high pressure receiver and the low pressure receiver, a third expansion device installed on the bypass pipe, the low pressure receiver and the third expansion device. First temperature detecting means for detecting a temperature between the two, a second temperature detecting means for detecting a temperature between the third expansion device and the high-voltage receiver, the load side heat exchanger and the first expansion device Fourth temperature detecting means for detecting the temperature between, and third temperature detecting means for detecting the temperature between the four-way valve and the load side heat exchanger,
Fifth temperature detecting means for detecting a temperature between the second expansion device and the heat source side heat exchanger, and sixth temperature detecting means for detecting a temperature between the four-way valve and the heat source side heat exchanger. A first pressure detecting means for detecting the pressure between the third expansion device and the low pressure receiver, a second pressure detecting means for detecting the pressure on the discharge side of the compressor, and a circulation in the refrigerant circuit. A computer for calculating the composition of the refrigerant, a composition adjuster for determining the opening of the third expansion device and adjusting the composition, and a main for calculating and opening the openings of the first and second expansion devices. A refrigeration / air-conditioning system characterized by having a controller. 23. The refrigeration / air conditioning system according to claim 22, further comprising a supercooling heat exchanger for exchanging heat between the main pipes before and after the high-pressure receiver and the pipe between the third expansion device and the low-pressure receiver. apparatus. 24. The bypass pipe for connecting the compressor discharge side pipe to the suction side pipe of the low pressure receiver or the inside of the low pressure receiver, and the opening / closing mechanism on the bypass pipe. Refrigeration and air conditioning equipment. 25. A first opening / closing mechanism installed between the high voltage receiver and the first expansion device, a second opening / closing mechanism installed between the high voltage receiver and the second expansion device, and a first opening / closing mechanism. Bypass pipe connecting the third opening / closing mechanism and the first subcooling heat exchanger, and the second opening / closing mechanism by bypassing the fourth opening / closing mechanism and the second subcooling heat exchanger. 23. A low-pressure receiver, wherein the first and second subcooling heat exchangers are built into the low-pressure receiver.
Refrigeration / air conditioning system as described. 26. The refrigeration / air-conditioning system according to claim 22, wherein the low-pressure receiver is divided into a portion for storing a liquid refrigerant and a buffer portion for preventing a temporary liquid return to the compressor. . 27. A compressor, a heat source side heat exchanger, a first expansion device, a load side heat exchanger, and a low pressure receiver are sequentially connected,
In a refrigeration cycle using a non-azeotropic mixed refrigerant in which several refrigerants are mixed, the refrigerant is branched from the refrigerant circuit between the heat source side heat exchanger and the first expansion device, and the second expansion device and supercooling heat exchange are performed. Through a bypass pipe connected to a low-pressure gas pipe, a first temperature detecting means for detecting the refrigerant temperature at the second throttle device inlet, and a first temperature detecting means for detecting the refrigerant temperature at the second throttle device outlet. Two temperature detecting means, a pressure detecting means for detecting the refrigerant pressure at the outlet of the second expansion device, a dryness detecting means installed near a branch portion of the main pipe with the bypass pipe, and the first and the second. Two temperature detection means, the pressure detection means and the detection value of the dryness detection means, the composition calculation device for calculating the composition of the refrigerant circulating in the refrigerant circuit, and the control of the refrigeration cycle according to the composition calculation value. Set value Refrigeration and air-conditioning apparatus characterized by change, and a main controller for controlling the refrigeration cycle.