Experimental

A schematic diagram of the heat pump-refrigerator apparatus is on the previous page. A compressor driven by an electric motor does work on the Freon-12 working fluid raising it to a high pressure and increasing its temperature. Heat is removed from the freon in the condensing heat exchanger, and the freon changes to the liquid phase in this constant pressure process. The liquid is then passed through an expansion valve to the low
pressure side of the apparatus. In this expansion process some of the liquid changes phase, obtaining the necessary heat of transformation from the internal energy of the remaining liquid. The two phase mixture then passes through the constant pressure evaporating heat exchanger and absorbs heat to convert all of the freon to the gas phase. The refrigerant flow meter measures the mass flow in the freon circuit, and thermometers are provided to measure the temperature of the working fluid at several points in the circuit.