The efficient control of the capacity and temperature in refrigeration systems is an important topic in refrigeration technology. With ET 422 different methods of capacity control can be investigated.
The components of a refrigeration circuit with refrigeration and freezing chambers are arranged clearly in the trainer. Solenoid valves enable the separate or parallel operation of the evaporators in the two chambers. The circuit is equipped with a capacity controller, a start-up controller and a combined pressures switch for the delivery and intake sides of the compressor. One heat exchanger each in the inlet of the two evaporators enables the supercooling of the refrigerant to be investigated for the efficiency of the process. The refrigeration capacity of the two individual chambers is controlled by a thermostat. The refrigeration chamber also features an evaporation pressure controller.
There are two defrosting methods for the freezing chamber: an electric defrost heater and a hot gas defrosting where hot refrigerant is fed directly from the compressor in the opposite direction through the evaporator.
The simulation of 12 different faults, such as e.g. faulty valves or clogged pipes, is activated using a touch panel PC.
Relevant measured values are transmitted directly to the touch panel PC and analysed. The software enables e.g. the representation of the cycle in the log p-h diagram.