Lab tests and models
Lab model to visualize the processes in the refrigerant cycle
This model which is equipped with a glass evaporator is used for the basic training courses in order to explain the components and visualize the processes in the refrigerant cycle.
Two manometers and four temperature measuring points help to monitor pressure and temperature changes in the system.
The speeds of the fans at the evaporator and the condenser can be adjusted in order to simulate load changes at the heat exchangers.
The unit is filled with the refrigerant R600a (isobutane).
Laboratory model for controlling the cooling capacity
This unit is used for cooling-capacity control experiments in the courses “refrigeration technology C” and “refrigeration in rail-vehicle air-conditioning systems”.
The cooling capacity of a reciprocating compressor can be reduced by frequency conversion of the supply voltage, a hot-gas bypass that opens into the suction and injection line, and a throttle valve in the suction line. In addition, a scroll compressor with digital control is installed.
During the lab measurements the function and efficiency of the different methods are compared.
R744 refrigeration unit for training purposes
The unit shown is used in the R744 training courses in order to demonstrate the function and the operational behavior of such a unit.
The operational data are recorded via a measurement data acquisition system and visualized on the display.
The refrigerating capacity can be measured at different heat loads, pressures, temperatures, air quantities and compressor speeds.
Compound refrigeration system with three cooling points
This model is used in the courses “refrigeration technology C” and “electrotechnology with regard to compound refrigeration units”. It consists of three semi-hermetic compressors, three cooling points and an electronic oil control system.
The lab tests deal with the technical installation of the refrigeration unit and test the function of the compound controller and the cold storage controller with thermostatic, pulse width modulated and stepping motor controlled expansion valve.
Test bench for expansion valves
The refrigerant cycle of this unit is equipped with six different expansion valves connected in parallel.
The function and the control behavior of three different capillary tubes — one automatic, one thermostatic and one pulse width modulated valve — can be tested at changing operating conditions.
The process can be observed in a liquid receiver by means of a glass component.
