Device and method for operating a refrigeration cycle without evaporator icing

A method for performing a refrigeration cycle without evaporator icing, comprising:

• providing a refrigerant gas;
• providing a compressor, having an inlet and an outlet, wherein low temperature, low pressure refrigerant gas enters the compressor inlet, is compressed therein and then is expelled from the outlet of the compressor as a high temperature, high pressure refrigerant gas;
• providing a condenser, having an inlet and an outlet, the inlet of the condenser being operatively coupled to the outlet of the compressor, wherein the high temperature, high pressure refrigerant gas enters the condenser inlet, releases heat energy therein to external air passing over an outer surface of the condenser, is condensed and is expelled from the outlet of the condenser as a low temperature, high pressure refrigerant liquid;
• providing a metering device, having an inlet and an outlet, the inlet of the meter being operatively coupled to the outlet of the condenser, wherein the low temperature, high pressure refrigerant liquid enters the metering means inlet and is controllably discharged from the metering means outlet as a low temperature, low pressure refrigerant liquid;
• providing an evaporator, having an inlet and an outlet, the inlet of the evaporator being operatively coupled to the outlet of the metering means, wherein the low temperature, low pressure refrigerant liquid enters the evaporator inlet, absorbs heat from water-vapor containing ambient air which has a dew point and which is at a higher temperature than the low temperature refrigerant liquid, through an outer surface of the evaporator, reducing the air temperature to below the dew point, as a result of which the water vapor condenses onto a surface of the evaporator while the refrigerant liquid vaporizes into a low temperature, low pressure refrigerant gas which is expelled from the outlet of the evaporator and is drawn into the inlet of the compressor to begin another cycle;
• providing a hot gas bypass means, having an inlet, an outlet, an open position and a closed position, the hot gas bypass means inlet being operatively coupled to the outlet of the compressor, the hot gas bypass means outlet being operatively coupled to the outlet of the metering means;
• providing a temperature-sensing means operatively coupled to the evaporator inlet;
• providing a controller operatively coupled to the temperature-sensing means and to the hot gas bypass means,
• wherein, the temperature-sensing means measures a temperature of the refrigerant liquid entering the evaporator and sends a temperature signal corresponding to that temperature to the controller, wherein if the temperature signal is at or below a first set point temperature, the controller sends an open signal to the hot gas bypass means permitting high temperature, high pressure refrigerant gas from the outlet of the compressor to mix with the low temperature, low pressure refrigerant liquid at the outlet of the metering means until the controller means receives a temperature signal from the temperature-sensing means that is at or above a second set point temperature at which time the controller sends a close signal to the hot gas bypass means;
• and,
• circulating the refrigerant from the compressor to the condenser to the metering means to the evaporator and thence back to the compressor in a refrigeration cycle.