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In a refrigerating air conditioning system using refrigerant such as CO2 used in a supercritical area, a highly efficient refrigerating air conditioning system is provided by adjusting the amount of refrigerant in a radiator which contributes to the efficiency of the system stably and quickly. Durin

In a refrigerating air conditioning system using refrigerant such as CO2 used in a supercritical area, a highly efficient refrigerating air conditioning system is provided by adjusting the amount of refrigerant in a radiator which contributes to the efficiency of the system stably and quickly. During heat utilizing operation, the superheat at the exit of an evaporator is controlled to a predetermined value by controlling the opening of an expansion valve provided on the upstream side of the evaporator, and an expansion valve is controlled so that the state of refrigerant in a connection pipe on the high-pressure side becomes a supercritical state. In this state, a flow rate control valve is controlled to change the density of the refrigerant stored in a refrigerant storage container and the amount of refrigerant existing in the radiator is adjusted. A target high-pressure value and a target value of the radiator exit temperature are set and the capacity of the compressor is controlled to obtain the target values, and the amount of refrigerant existing in the radiator is adjusted by the refrigerant amount adjusting circuit.

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1. A refrigerating air conditioning system comprising: a refrigeration cycle configured to circulate refrigerant through a compressor, a user side heat exchanger, a user side decompression device, a heat source side decompression device and a heat source side heat exchanger and operated with a high-

1. A refrigerating air conditioning system comprising: a refrigeration cycle configured to circulate refrigerant through a compressor, a user side heat exchanger, a user side decompression device, a heat source side decompression device and a heat source side heat exchanger and operated with a high-pressure value being a pressure higher than a critical pressure of the refrigerant and a low-pressure value being a pressure lower than the critical pressure;a refrigerant amount adjusting circuit including, a refrigerant storage container, a high-pressure low-temperature refrigerant connecting pipe for connecting and disconnecting the refrigerant pipe between the heat source side decompression device and the user side decompression device and the refrigerant storage container,a low-pressure low-temperature refrigerant connecting pipe for connecting and disconnecting the refrigerant storage container and a suction side of the compressor, anda high-pressure high-temperature refrigerant connecting pipe for connecting and disconnecting the refrigerant storage container and a discharge side of the compressor, wherein the refrigerant amount adjusting circuit can increase and decrease the amount of refrigerant existing in the refrigeration cycle;superheat controlling means for controlling the heat source side decompression device so that the degree of superheat at an exit of the heat source side heat exchanger becomes a predetermined value during a heat utilizing operation in which heat is supplied by the user side heat exchanger;refrigerant amount controlling means for changing the amount of refrigerant in the refrigerant storage container which adjusts the amount of refrigerant existing in the user side heat exchanger, so that the temperature or the pressure of the refrigerant at an exit of the user side heat exchanger becomes a predetermined state by, during the heat utilizing operation,when a high-pressure value of the refrigeration cycle is smaller than a high-pressure target value or an exit refrigerant temperature of the user side heat exchanger is larger than an exit refrigerant target temperature, cutting off the high-pressure low-temperature refrigerant connecting pipe and connecting the high-pressure high-temperature refrigerant connecting pipe or the low-pressure low-temperature refrigerant connecting pipe, so that a small-density refrigerant is stored in the refrigerant storage container, andwhen the high-pressure value of the refrigeration cycle is larger than the high-pressure target value or the exit refrigerant temperature of the user side heat exchanger is smaller than the exit refrigerant target temperature, connecting the high-pressure low-temperature refrigerant connecting pipe or the high-pressure high-temperature connecting pipe and cutting off the low-pressure low-temperature refrigerant connecting pipe, so that a large-density refrigerant is stored in the refrigerant storage container; and decompression device controlling means for controlling the user side decompression device so that the state of the refrigerant in a pipe that connects the heat source side decompression device and the user side decompression device becomes a supercritical state. 2. The refrigerating air conditioning system according to claim 1, comprising compressor controlling means for controlling a capacity of the compressor, and target setting means for setting a target high-pressure value and a target value of the refrigerant temperature at the exit of the user side heat exchanger, so as to obtain an amount of heat required in the user side heat exchanger, wherein the refrigerant amount controlling means and the compressor controlling means controls the high-pressure value of the refrigeration cycle to be the high-pressure target value and controls the refrigerant temperature at the exit of the user side heat exchanger to be the target value of the refrigerant temperature at the exit. 3. The refrigerating air conditioning system according to claim 2, wherein the compressor controlling means controls the capacity of the compressor so that the high-pressure value of the refrigeration cycle becomes the target high-pressure value, and the refrigerant amount controlling means controls the refrigerant amount adjusting circuit so that the refrigerant temperature at the exit of the user side heat exchanger becomes the target value of refrigerant temperature at the exit. 4. The refrigerating air conditioning system according to claim 1, comprising a plurality of indoor machines each having a user side heat exchanger and the user side decompression device. 5. The refrigerating air conditioning system according to claim 4, wherein the decompression device controlling means adjusts the flow resistances of each user side decompression device according to a predetermined capacity of the corresponding user side heat exchanger. 6. The refrigerating air conditioning system according to claim 4, wherein the decompression device controlling means adjusts the flow resistance of each user side decompression devices so that the refrigerant temperature at the exit of the corresponding user side heat exchangers or a representative refrigerant temperature which represents these refrigerant temperatures becomes a target value of the refrigerant temperature at the exit which is determined by the operating state of the refrigeration cycle. 7. The refrigerating air conditioning system according to claim 6, wherein the decompression device controlling means adjusts the flow resistance of each user side decompression device so that the refrigerant temperature at the exit of the corresponding user side heat exchanger fall within a predetermined temperature difference from the refrigerant temperature at the inlet port of the heat source side decompression device. 8. A refrigerating air conditioning system comprising: a refrigeration cycle configured to circulate refrigerant through a compressor, a heat source side heat exchanger, a heat source side decompression device, a user side decompression device and a user side heat exchanger and operated with a high-pressure value being a pressure higher than a critical pressure of the refrigerant and a low-pressure value being a pressure lower than the critical pressure;a refrigerant amount adjusting circuit including, a refrigerant storage container, a high-pressure low-temperature refrigerant connecting pipe for connecting and disconnecting the refrigerant pipe between the heat source side decompression device and the user side decompression device and the refrigerant storage container,a low-pressure low-temperature refrigerant connecting pipe for connecting and disconnecting the refrigerant storage container and a suction side of the compressor, anda high-pressure high-temperature refrigerant connecting pipe for connecting and disconnecting the refrigerant storage container and a discharge side of the compressor, wherein the refrigerant amount adjusting circuit can increase and decrease the amount of refrigerant existing in the refrigeration cycle;superheat controlling means for controlling the user side decompression device so that the degree of superheat at an exit of the user side heat exchanger becomes a predetermined value during a cold heat utilizing operation in which cold heat is supplied by the user side heat exchanger;refrigerant amount controlling means for changing the amount of refrigerant in the refrigerant storage container which adjusts the amount of refrigerant existing in the heat source side heat exchanger so that the temperature or the pressure of the refrigerant at the exit of the heat source side heat exchanger becomes a predetermined state by, during the heat utilizing operation, when a high-pressure value of the refrigeration cycle is smaller than a high-pressure target value or an exit refrigerant temperature of the heat source side heat exchanger is larger than an exit refrigerant target temperature, cutting off the high-pressure low-temperature refrigerant connecting pipe and connecting the high-pressure high-temperature refrigerant connecting pipe or the low-pressure low-temperature refrigerant connecting pipe, so that a small-density refrigerant is stored in the refrigerant storage container, andwhen the high-pressure value of the refrigeration cycle is larger than the high-pressure target value or the exit refrigerant temperature of the heat source side heat exchanger is smaller than the exit refrigerant target temperature, connecting the high-pressure low-temperature refrigerant connecting pipe or the high-pressure high-temperature connecting pipe and cutting off the low-pressure low-temperature refrigerant connecting pipe, so that a large-density refrigerant is stored in the refrigerant storage container; anddecompression device controlling means for controlling the heat source side decompression device so that the state of the refrigerant in a pipe that connects the heat source side decompression device and the user side decompression devices becomes a supercritical state. 9. The refrigerating air conditioning system according to claim 8, comprising target value setting means for setting a target high-pressure value or a target value of the refrigerant temperature at the exit of the heat source side heat exchanger, wherein the refrigerant amount controlling means controls the refrigerant amount adjusting circuit so as to satisfy at least one of the target values. 10. The refrigerating air conditioning system according to claim 8, wherein the compressor is a variable capacity compressor and compressor controlling means controls the capacity of the compressor so that the low-pressure value of the refrigeration cycle becomes a predetermined value. 11. The refrigerating air conditioning system according to claim 8, wherein the compressor is a variable capacity compressor and compressor controlling means controls the capacity of the compressor so that an amount of cold heat required in the user side heat exchangers can be obtained. 12. A refrigerating air conditioning system comprising: a refrigeration cycle for circulating refrigerant through a compressor, a heat source side heat exchanger, a heat source side decompression device, a user side decompression device, and a user side heat exchanger which are connected with a refrigerant pipe, and operating with a high-pressure value being a pressure higher than a critical pressure of the refrigerant and a low-pressure value being a pressure lower than the critical pressure;a refrigerant amount adjusting circuit including, a refrigerant storage container, a high-pressure low-temperature refrigerant connecting pipe which can connect and disconnect the refrigerant pipe between the heat source side decompression device and the user side decompression device and the refrigerant storage container,a low-pressure low-temperature refrigerant connecting pipe which can connect and disconnect the refrigerant storage container and a suction side of the compressor, anda high-pressure high-temperature refrigerant connecting pipe which can connect and disconnect the refrigerant storage container and a discharge side of the compressor, wherein the refrigerant amount adjusting circuit can increase and decrease the amount of refrigerant existing in the refrigeration cycle;a heat utilizing operation mode in which the refrigerant is circulated through the compressor, the user side heat exchanger, the user side decompression device, the heat source side decompression device, and the heat source side heat exchanger in order, and the user side heat exchanger is operated as a radiator and the heat source side heat exchanger is operated as an evaporator;a cold heat utilizing mode in which the refrigerant is circulated through the compressor, the heat source side heat exchanger, the heat source side decompression device, the user side decompression device and the user side heat exchanger in order, and the user side heat exchanger is operated as an evaporator and the heat source side heat exchanger is operated as a radiator;a flow path switching valve for switching the flow of the refrigerant between the heat utilizing operation mode and the cold heat utilizing operation mode;superheat controlling means for controlling the decompression device disposed on the upstream side of the heat exchanger which serves as the evaporator so that the superheat at the exit of the heat exchanger which serves as the evaporator becomes a predetermined value when being operated in the heat utilizing operation mode and the cold heat utilizing operation mode;and refrigerant amount controlling means for changing the amount of refrigerant in the refrigerant storage container which adjusts the amount of refrigerant existing in the heat exchanger which serves as the radiator to control the temperature or the pressure of the refrigerant at the exit of the heat exchanger which serves as a radiator to become a predetermined state, by,when a high-pressure value of the refrigeration cycle is smaller than a high-pressure target value or an exit refrigerant temperature of the heat exchanger which serves as a radiator is larger than an exit refrigerant target temperature, cutting off the high-pressure low-temperature refrigerant connecting pipe and connecting the high-pressure high-temperature refrigerant connecting pipe or the a low-pressure low-temperature refrigerant connecting pipe, so that a small-density refrigerant is stored in the refrigerant storage container, andwhen the high-pressure value of the refrigeration cycle is larger than the high-pressure target value or the exit refrigerant temperature of the heat exchanger which serves as a radiator is smaller than the exit refrigerant target temperature, connecting the high-pressure low-temperature refrigerant connecting pipe or the high-pressure high-temperature refrigerant connecting pipe and cutting off the low-pressure low-temperature refrigerant connecting pipe to change the refrigerant amount in the refrigerant storage container, so that a large-density refrigerant is stored in the refrigerant storage container; and decompression device controlling means for controlling each heat source side decompression device and user side decompression device so that the state of the refrigerant in a pipe that connects the heat source side decompression device and the user side decompression device becomes a supercritical state. 13. The refrigerating air conditioning system according to claim 8, comprising a plurality of the indoor machines each having the user side heat exchanger and the user side decompression device. 14. The refrigerating air conditioning system according to claim 1, comprising a temperature adjusting heat exchange unit for adjusting the temperature of the refrigerant flowing in the pipe which connects the user side decompression device and the heat source side decompression device. 15. The refrigerating air conditioning system according to claim 14, wherein the temperature adjusting heat exchange unit is provided on the upstream side of a connecting portion between the refrigeration cycle refrigerant pipe and the refrigerant amount adjusting circuit, and heat is exchanged between refrigerant flowing on the upstream side of the connecting portion and low-pressure refrigerant obtained by branching and decompressing part of the refrigerant flowing on the upstream side, thereby adjusting the temperature of the refrigerant flowing at the connecting portion. 16. The refrigerating air conditioning system according to claim 1, wherein the compressor, the heat source side decompression device, the heat source side heat exchanger and the refrigerant storage container are stored in an outdoor machine, the user side heat exchangers and the user side decompression devices are stored in the indoor machines, and the indoor machines and the outdoor machine are connected by the refrigerant pipes. 17. The refrigerating air conditioning system according to claim 1, wherein carbon dioxide is used as the refrigerant. 18. A method of controlling the operation of a refrigerating air conditioning system comprising: a refrigeration cycle configured by circulating refrigerant through a compressor, a radiator, a user side decompression device, a heat source side decompression device, and an evaporator;a refrigerant amount adjusting circuit including, a refrigerant storage container, a high-pressure low-temperature refrigerant connecting pipe for connecting and disconnecting the refrigerant pipe between the heat source side decompression device and the user side decompression device and the refrigerant storage container,a low-pressure low-temperature refrigerant connecting pipe for connecting and disconnecting the refrigerant storage container and a suction side of the compressor, anda high-pressure high-temperature refrigerant connecting pipe for connecting and disconnecting the refrigerant storage container and a discharge side of the compressor, whereinthe refrigerant amount adjusting circuit can increase and decrease the amount of refrigerant existing in the refrigeration cycle;a refrigeration air conditioning step for performing an operation with the high pressure side of the refrigeration cycle being a critical pressure or more and the low pressure side of the refrigeration cycle being the critical pressure or less to perform refrigeration air conditioning in the evaporator or the radiator;a superheat controlling step for controlling a decompression device disposed at the upstream side of the evaporator so that the superheat at the exit of the evaporator is a predetermined value;a refrigerant amount controlling step for changing the amount of refrigerant in the refrigerant storage container which adjusts the amount of refrigerant existing in the heat exchanger which serves as a radiator so that the temperature or the pressure of the refrigerant at the exit of the heat exchanger which serves as a radiator becomes a state of the target value by,when a high-pressure value of the refrigeration cycle is smaller than a high-pressure target value or an exit refrigerant temperature of the heat exchanger which serves as a radiator is larger than an exit refrigerant target temperature, cutting off the high-pressure low-temperature refrigerant connecting pipe and connecting the high-pressure high-temperature refrigerant connecting pipe or the low-pressure low-temperature connecting pipe, so that a small-density refrigerant is stored in the refrigerant storage container, andwhen the high-pressure value of the refrigeration cycle is larger than the high-pressure target value or the exit refrigerant temperature of the heat exchanger which serves as a radiator is smaller than the exit refrigerant target temperature, connecting the high-pressure low-temperature refrigerant connecting pipe or the high-pressure high-temperature connecting pipe and cutting off the low-pressure low-temperature refrigerant connecting pipe, so that a large-density refrigerant is stored in the refrigerant storage container; and a decompression device controlling step for controlling each of the heat source side decompression device and the user side decompression device so that the state of the refrigerant in a pipe that connects the heat source side decompression device and the user side decompression device becomes a supercritical state. 19. The method of controlling the operation of a refrigerating air conditioning system according to claim 18, wherein intervals of the superheat control performed at the exit of the evaporator in the superheat controlling step are shorter than intervals of the refrigerant amount adjusting control performed in the refrigerant amount controlling step. 20. The method of controlling the operation of a refrigerating air conditioning system according to claim 18, comprising a target setting step for setting a high-pressure target and a target value of the refrigerant temperature at the radiator exit for obtaining an amount of heat required in the radiator, and a compressor controlling step for controlling the capacity of the compressor so that the high-pressure value of the circulating refrigerant becomes the target high pressure value, wherein the refrigerant amount controlling step is to adjust the amount of refrigerant so that the temperature of the circulating refrigerant at the radiator exit becomes the target value of the refrigerant temperature at the radiator exit so as to supply heat from the radiator for use. 21. The method of controlling the operation of a refrigerating air conditioning system according to claim 18, comprising a target setting step for setting a target high-pressure value, wherein the refrigerant amount controlling step is to adjust the amount of refrigerant so that the high-pressure value of the circulating refrigerant becomes the high-pressure target value so as to supply cold heat from the evaporator for use. 22. The method of controlling the operation of a refrigerating air conditioning system according to claim 21, comprising a compressor controlling step for controlling the capacity of the compressor so that the low-pressure value of the circulating refrigerant becomes a predetermined value. 23. The method of controlling the operation of a refrigerating air conditioning system according to claim 21, comprising a compressor controlling step for controlling the capacity of the compressor so that an amount of cold heat required in the evaporator can be obtained. 24. The method of controlling the operation of a refrigerating air conditioning system according to claim 20, wherein intervals of the capacity control of the compressor performed in the compressor controlling step are shorter than intervals of the refrigerant amount adjusting control performed in the refrigerant amount controlling step.