Exam Question
(a) Make a detailed sketch of a Direct Expansion Two Room Refrigeration system. (10)
(b) Give a full description of such a Refrigeration System, explaining the purpose of the relevant control and safety devices. (6)
Class 4 (4th Engineer)
MEKG
📅 Apr 2025
Reference Answer
### (a) Detailed Sketch of a Direct Expansion Two Room Refrigeration System
A detailed sketch would illustrate the layout of components. The key features to include are a single compressor, condenser, and receiver supplying two separate circuits in parallel. Each circuit serves one refrigerated room and consists of a liquid line solenoid valve, a thermostatic expansion valve (TEV), and an evaporator.
Crucially, to maintain different temperatures, the suction line from the warmer room's evaporator must be fitted with an Evaporator Pressure Regulator (EPR) or Back Pressure Valve (BPV). The suction line from the colder room's evaporator should have a check valve to prevent reverse flow from the higher-pressure suction line of the warmer room during off-cycles.
### (b) Full Description of the Refrigeration System
A detailed sketch would illustrate the layout of components. The key features to include are a single compressor, condenser, and receiver supplying two separate circuits in parallel. Each circuit serves one refrigerated room and consists of a liquid line solenoid valve, a thermostatic expansion valve (TEV), and an evaporator.
Crucially, to maintain different temperatures, the suction line from the warmer room's evaporator must be fitted with an Evaporator Pressure Regulator (EPR) or Back Pressure Valve (BPV). The suction line from the colder room's evaporator should have a check valve to prevent reverse flow from the higher-pressure suction line of the warmer room during off-cycles.
### (b) Full Description of the Refrigeration System
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