The base unit RAC 076 includes the main components of a refrigeration circuit: a condensing unit with compressor, condenser and receiver and a refrigeration chamber with integrated evaporator, fan for forced ventilation and an electric defrost heater. A pressure switch protects the compressor against excessive pressure. The refrigerant flow can be modified via shut-off valves. Together with the components from e.g. heat exchanger, flow meter or manometer, simple refrigeration circuits are realised. For continued experiments additional refrigeration components are used, e.g. post-injection valve, capacity controller or defrost timer. All components of the training system have ball valves at the connections. Using the required accessory kit, the components are connected into a complete refrigeration system. For the complete experimental set-up, laboratory workplace with frame for mounting the components and power supply, is required. The CFC-free refrigerant R134a serves as working medium. With the service set additional exercises for the filling and evacuation of refrigeration systems are carried out.