Transcritical vapor compression system and method of operating including refrigerant storage tank and non-variable expansion device

A transcritical vapor compression system comprising:

• a fluid circuit circulating a refrigerant in a closed loop, said fluid circuit having operably disposed therein, in serial order, a compressor, a first heat exchanger, at least one non-variable expansion device and a second heat exchanger wherein said compressor compresses the refrigerant from a low pressure to a supercritical pressure, said first heat exchanger is positioned in a high pressure side of said fluid circuit and contains refrigerant at a first supercritical pressure and said second heat exchanger is positioned in a low pressure side of said fluid circuit and contains refrigerant at a second subcritical pressure, said at least one non-variable expansion device reducing the pressure of the refrigerant from a supercritical pressure to a relatively lower pressure wherein said at least one non-variable expansion device defines a pressure reduction substantially equivalent to the pressure difference between said first pressure and said second pressure;
• a refrigerant storage vessel in fluid communication with said fluid circuit between said first and second heat exchangers;
• and
• a temperature adjustment device disposed in thermal exchange with said refrigerant storage vessel, said temperature adjustment device operable to transfer heat to refrigerant in said storage vessel and to remove heat from refrigerant in said storage vessel wherein a temperature of refrigerant in said refrigerant storage vessel is adjustable with said temperature adjustment device.

A method of controlling a transcritical vapor compression system, said method comprising:

• providing a fluid circuit circulating a refrigerant in a closed loop, the fluid circuit having operably disposed therein, in serial order, a compressor, a first heat exchanger, at least one non-variable expansion device and a second heat exchanger;
• compressing the refrigerant from a low pressure to a supercritical pressure in the compressor;
• removing thermal energy from the refrigerant in the first heat exchanger;
• reducing the pressure of the refrigerant in the at least one non-variable expansion device wherein said at least one non-variable expansion device defines a pressure reduction substantially equivalent to a pressure difference between a first supercritical pressure of the refrigerant within the first heat exchanger and a second subcritical pressure of the refrigerant within the second heat exchanger;
• adding thermal energy to the refrigerant in the second heat exchanger;
• providing a refrigerant storage vessel in fluid communication with said fluid circuit via an open fluid conduit which provides both outflow and inflow of refrigerant to and from the refrigerant storage vessel and the fluid circuit;
• providing a thermal control device in thermal exchange relationship with the refrigerant storage vessel;
• and
• controlling the mass of refrigerant in the refrigerant storage vessel with the thermal control device to thereby control the mass of refrigerant in the fluid circuit and thereby regulate the capacity of the system.

A compression system comprising:

• a fluid circuit circulating a refrigerant in a closed loop, said fluid circuit having operably disposed therein, in serial order, a compressor, a first heat exchanger, at least one expansion device and a second heat exchanger wherein said compressor compresses the refrigerant from a low pressure to a high pressure, said first heat exchanger is positioned in a high pressure side of said fluid circuit and contains refrigerant at the high pressure and said second heat exchanger is positioned in a low pressure side of said fluid circuit and contains refrigerant at the low pressure, said at least one expansion device reducing the pressure of the refrigerant from the high pressure to the low pressure and defining a pressure reduction substantially equivalent to the pressure difference between the low pressure and the high pressure;
• a refrigerant storage vessel in fluid communication with said fluid circuit, said refrigerant storage vessel having a variable mass of refrigerant therein;
• and
• a thermal control device disposed in thermal exchange relationship with said refrigerant storage vessel, said temperature adjustment device operable to transfer heat to refrigerant in said storage vessel and to remove heat from refrigerant in said storage vessel wherein the mass of refrigerant within said refrigerant storage vessel is adjustable with said thermal control device to in turn adjust the mass of refrigerant in said fluid circuit.

A transcritical vapor compression system comprising:

• a fluid circuit circulating a refrigerant in a closed loop, said fluid circuit having operably disposed therein, in serial order, a compressor, a first heat exchanger, at least one non-variable expansion device and a second heat exchanger wherein said compressor compresses the refrigerant from a low pressure to a supercritical pressure, said first heat exchanger is positioned in a high pressure side of said fluid circuit and contains refrigerant at a first supercritical pressure and said second heat exchanger is positioned in a low pressure side of said fluid circuit and contains refrigerant at a second subcritical pressure, said at least one non-variable expansion device reducing the pressure of the refrigerant from a supercritical pressure to a relatively lower subcritical pressure wherein said at least one non-variable expansion device defines a pressure reduction substantially equivalent to the pressure difference between said first pressure and said second pressure;
• a refrigerant storage vessel in fluid communication with said fluid circuit, said refrigerant storage vessel having a variable mass of refrigerant stored therein;
• and
• a thermal control device disposed in thermal exchange relationship with said refrigerant storage vessel, wherein the mass of refrigerant within said refrigerant storage vessel is adjustable with said thermal control device to in turn adjust the mass of refrigerant in said fluid circuit, wherein said thermal control device comprises an air moving device configured to move air across said refrigerant storage vessel.