For demonstration of the function of an electric compression heat pump.

• Symmetrical construction to show that the refrigerator and heat pump work according to the same principle. Heat exchanger (evaporator and condenser) of nickel-plated copper pipes.

Two insulated water containers serve as heat reservoirs and represent heat dissipation resp. heat-absorbing medium. Cable markings on the front of the appliance have been made in different colors (hot / cold, liquid / gaseous), with symbols for control valve and compressor. The rear wall is detachable so that the piping can be studied. The phase transition between liquid and gaseous form can be studied in 2 small windows. Other parts of the circuit can be studied with 2 manometers (on the high and low pressure side) and 4 temperature measuring points (before and after the heat exchangers). Thermostat-controlled expansion valve protects against handling errors and pressure valve triggers in case of abnormal overpressure and underpressure.

Some examinations that can be performed with the equipment:

Pressure, temperature and different conditions in the heat pump's circuit.
The working medium's vapor pressure curve, Mollier diagram.
The heat pump's energy balance.
Determination of power figures at different evaporation temperatures.
Combination of heat pump and solar collector.

Technical data

Working medium: R134a (Tetrafluoroethane).
Pressure switch: 1.5 MPa on the high pressure side. 0.2 MPa on the low pressure side.
Throttle valve: Thermostat controlled.
Voltage: 220 V / 50 Hz.
Rated power: 120 W.
Power ratio: approx. 2.2.
Size: 750 × 350 × 630 mm.