The efficient use of energy in refrigeration is an important topic. A higher capacity requirement is implemented in industry by connecting several small compressors in parallel. This permits the optimum adaptation to the capacity requirement by adding and removing compressors. includes three compressors connected in parallel for this purpose which can be switched on or off via a controller.
The components of a refrigeration circuit with three compressors are arranged clearly in the trainer. A glycol-water circuit with pump and tank with heater serves as cooling load at the evaporator. An internal heat exchanger in the refrigeration circuit allows for the refrigerant supercooling to be examined for process efficiency. The quantitative analysis of the efficiency takes place using an energy balance in the glycol-water circuit and by measuring the electrical power of the compressors.
Relevant measured values are recorded by sensors. The measured values can be read on digital displays. At the same time, the measured values can also be transmitted directly to a PC via USB. The data acquisition software is included.
The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the experiments.
The unit shall perform the following experiments and investigations:
Learning Objectives / Experiments
Variables affecting energy efficiency
Controller parameters
Refrigerant supercooling
Interconnected operation of compressors
Operation of a multicompressor controller
Methods for returning oil in a multicompressor
Refrigeration system
Representation of the thermodynamic cycle in the
Log p-h diagram
Specification
Refrigeration system in multicompressor operation to investigate energy efficiency
Refrigeration circuit with 3 compressors connected in parallel, condenser, thermostatic expansion valve and coaxial coil heat exchanger as evaporator
Heat exchanger for refrigerant supercooling can be added via valves
Glycol-water circuit includes pump and tank with heater serving as cooling load at the evaporator
Multicompressor controller for the parallel operation of the compressors
Separation of oil from the refrigerant on the delivery side and return to the intake side of the compressors
Fan at the condenser with adjustable speed
Software for data acquisition via USB under Windows Vista or Windows 7