With simple and clear experiments this equipment is intended mainly as a basic introduction to refrigeration.

ET 900 enables familiarisation with the operation and handling of a refrigeration system. The experimental unit includes all the necessary components for a fully operational refrigeration circuit, such as compressor, condenser, evaporator and a capillary tube as expansion element. Other components complement the scope of the equipment: display and control panel, pressure switches and pressure display to protect the compressor against excessive pressure and a flow meter and sight glass with filter/drier. Condenser and evaporator are each present twice: as air/refrigerant heat exchanger and as water/refrigerant heat exchanger. This allows for different component combinations.

The components are mounted on plates and form installation-ready modules. 6 of the 8 modules are positioned in the frame at any one time and connected via hoses and supply cables. This allows for the construction of different simple compression refrigeration systems. For filling the system the refrigerant filling and evacuation equipment ET 150.01 is recommended.

In experiments the processes in the equipment and the changes in the refrigerant state are initially demonstrated. Continued experiments allow the use of the equipment as a refrigeration system and as a heat pump. Pressures, flow rates power consumption of the compressor are displayed as important characteristic variables of refrigeration circuits. The temperature is measured by interlaboratory thermometers.