Identifying faults in refrigeration systems requires comprehensive knowledge This includes knowledge of the structure and the task of the individual components. With this, the design and components of a refrigeration system can be examined. The simulation of typical errors extends the scope of the experiment. The components of a refrigeration circuit with refrigeration and freezing chambers are arranged clearly in the trainer. Solenoid valves enable the individual or parallel operation of the evaporators in the two chambers. The circuit is equipped with a combined pressure switch for the delivery and intake side of the compressor. The refrigeration chamber features an evaporation pressure controller. The effect of the evaporation pressure controller on the overall process is being examined. An inner heat exchanger in the inlet of the two evaporators is used for supercooling the refrigerant to increase the efficiency of the process. At the same time the intake gas is superheated.
Learning Objectives/Experiments
- Design and components of a refrigeration system with 2 evaporators
- Components and their functions
- Compressor, condenser, evaporator
- Thermostatic expansion valve
- Evaporation pressure controller
- Pressure switch
- Electric defrost heater
- Thermodynamics of the refrigeration cycle
- Effect of refrigerant supercooling
- Representation of the thermodynamic cycle in the log p-h diagram
- Determination of important characteristic variables: coefficient of performance, refrigeration capacity, compressor work
- Fault finding in refrigeration system components
Specification
- Investigation of a refrigeration system with refrigeration and freezing chambers
- Refrigeration circuit with compressor, condenser and 2 evaporators with thermostatic expansion valve and evaporation pressure controller
- Insulated freezing chamber with fan and electric defrost heater
- Insulated refrigeration chamber with evaporation pressure controller
- Heat exchanger for refrigerant supercooling
- Individual or parallel operation of the chambers via solenoid valves
- Sensors record pressure and temperature
- Refrigerant mass flow rate calculated in the software from recorded measured values
- Simulation of 18 faults
Technical Data
- Compressor
- Power consumption: 565W at 7,2/54,4°C
- Refrigeration capacity: 1363W at 7,2/54,4°C
- Condenser with fan
- Volumetric air flow rate: 290m3/h
- transfer area: 1,5m2
- Refrigeration chamber
- Evaporator transfer area: 1,06m2
- Freezing chamber
- Evaporator transfer area: 2,42m2
- Volumetric air flow rate, fan: 135m3/h
- Electric defrost heater: approx. 150W
- Evaporation pressure controller: 0…5,5bar
- Refrigerant: R513A, GWP: 631
- Filling volume: 1,5kg
- CO2-equivalent: 0,9t
- Measuring ranges
- Temperature: 12x -50…120°C
- Pressure: 3x -1…15bar, 3x -1…9bar, 3x -1…24bar
- Power: 0…1125W
- Flow rate: 1…11,5L/h
- 230V, 50Hz, 1 phase
- 230V, 60Hz, 1 phase; 120V, 60Hz, 1 phase
