Refrigeration apparatus and method for controlling the same

A refrigeration apparatus comprising:

• a condensing unit;
• a flow distributor;
• an expansion valve;
• an evaporator connected to said condensing unit via said flow distributor;
• pressure detecting means for detecting condensation pressure of the refrigerant, said pressure detecting means being located upstream of said expansion value and downstream of said condensing unit;
• a refrigerant liquid receiver provided downstream of said condensing unit and upstream of said pressure detecting means;
• calculation means for calculating a target condensation pressure of refrigerant necessary for the refrigerant to be an evaporation temperature in the evaporator;
• and
• controlling means for controlling said condensing unit so that the condensation pressure of the refrigerant becomes equal to or more than the target condensation pressure,
• wherein said condensing unit includes an adjustable valve at an output side of said condensing unit to control the flow of the refrigerant, wherein said adjustable valve is provided downstream of said condensing unit and upstream of said expansion valve, and wherein said controlling means is configured to control the adjustable valve;
• and
• wherein said calculation, means calculates the target condensation pressure according to the following equation:
• target condensation pressure=1125.08+(9.07965*X)+(−0.101693*X*X)+(40.8041*Y)+(1.60973*X*Y)+(0.0177658*X*X*Y)+(−0.0547654*Y*Y)+(−0.00318583*X*Y*Y)+(−0.000044704*X*X*Y*Y),
• where X is the evaporation temperature, and Y is the liquid refrigerant temperature.

A refrigeration apparatus comprising:

• a condensing unit;
• a flow distributor;
• an expansion valve;
• an evaporator connected to said condensing unit via said flow distributor;
• a pressure detector configured to detect condensation pressure of the refrigerant, said pressure detector being located upstream of said expansion value and downstream of said condensing unit;
• a calculation unit configured to calculate a target condensation pressure of the refrigerant necessary for the refrigerant to be an evaporation temperature in the evaporator;
• a controller configured to control said condensing unit so that the condensation pressure of the refrigerant becomes equal to or more than the target condensation pressure;
• a liquid temperature sensor configured to detect a liquid refrigerant temperature upstream of said expansion valve;
• and
• an evaporation temperature sensor configured to detect an evaporation temperature,
• wherein said calculation unit is configured to calculate the target condensation pressure based on the detected liquid refrigerant temperature and the detected evaporation temperature, and
• wherein said calculation unit is configured to calculate the target condensation pressure according to the following equation:
• target condensation pressure=1125.08+(9.07965*X)+(−0.101693*X*X)+(40.8041*Y)+(1.60973*X*Y)+(0.0177658*X*X*Y)+(−0.0547654*Y*Y)+(−0.00318583*X*Y*Y)+(−0.000044704*X*X*Y*Y),
• where X is the evaporation temperature, and Y is the liquid refrigerant temperature.

A method for controlling a refrigeration apparatus, the method comprising:

• detecting condensation pressure of refrigerant at a location upstream of an expansion valve, downstream of a condensing unit, and downstream of a refrigerant liquid receiver provided downstream of the condensing unit;
• calculating a target condensation pressure of the refrigerant necessary for the refrigerant to be an evaporation temperature in the evaporator;
• and
• controlling the condensing unit connected to the evaporator via a flow distributor so that the condensation pressure of the refrigerant becomes equal to or more than the target condensation pressure,
• wherein said condensing unit includes an adjustable valve at an output side of said condensing unit to control the flow of the refrigerant, wherein said adjustable valve is provided downstream of said condensing unit and upstream of said expansion valve, and wherein a controller is configured to control the adjustable valve;
• and
• wherein said calculation comprises calculating the target condensation pressure according to the following equation:
• target condensation pressure=1125.08+(9.07965*X)+(−0.101693*X*X)+(40.8041*Y)+(1.60973*X*Y)+(0.0177658*X*X*Y)+(−0.0547654*Y*Y)+(−0.00318583*X*Y*Y)+(−0.000044704*X*X*Y*Y),
• where X is the evaporation temperature, and Y is the liquid refrigerant temperature.

A computer readable medium for storing a computer program, which when executed, controls a computer to perform the steps of:

• detecting condensation pressure of refrigerant at a location upstream of an expansion valve, downstream of a condensing unit, and downstream of a refrigerant liquid receiver provided downstream of the condensing unit;
• calculating a target condensation pressure of the refrigerant necessary for the refrigerant to be an evaporation temperature in the evaporator;
• and
• controlling the condensing unit connected to the evaporator via a flow distributor so that the condensation pressure of the refrigerant becomes equal to or more than the target condensation pressure,
• wherein said condensing unit includes an adjustable valve at an output side of said condensing unit to control the flow of the refrigerant, wherein said adjustable valve is provided downstream of said condensing unit and upstream of said expansion valve, and wherein a controller is configured to control the adjustable valve;
• and
• wherein said calculating a target condensation pressure is according to the following equation:
• target condensation pressure=1125.08+(9.07965*X)+(−0.101693*X*X)+(40.8041*Y)+(1.60973*X*Y)+(0.0177658*X*X*Y)+(−0.0547654*Y*Y)+(−0.00318583*X*Y*Y)+(−0.000044704*X*X*Y*Y),
• where X is the evaporation temperature, and Y is the liquid refrigerant temperature.