The pressure gauges measure the low and high freon pressures. Water flow meters and thermometers are provided for each of the constant flow calorimeters surrounding the heat exchangers. A Watt-meter measures the electrical work supplied to the electric motor driving the compressor.

You should make measurements that permit the COP to be determined for the Heat Pump and the Refrigerator for well defined operating conditions. It is important to realize that the device takes a long time to come to steady state and such a condition should be verified by observing the time dependence of the temperatures, the pressures, the freon and water flows, and the power consumption of the electric motor.

Pressure-Enthalpy and Temperature-Entropy charts are provided for the Freon-12 working fluid. This data and measurements on the freon circuit should be used to compute the COP from the standpoint of the working fluid.