Exam Question

### (a) Domestic Refrigeration System: Sketch, Operation, and Maintenance
**System Description and Operation**
A ship's domestic refrigeration system operates on the vapor-compression refrigeration cycle. It is designed to maintain low temperatures in provision stores (e.g., meat room, fish room, vegetable room) for preserving food. The system utilizes a Hydrofluorocarbon (HFC) refrigerant, such as R-134a, which has zero Ozone Depletion Potential (ODP). The system consists of the following key components:
1. **Compressor**: This is the heart of the system, acting as a circulation pump for the refrigerant. It draws low-pressure, low-temperature refrigerant vapor from the evaporator and compresses it into a high-pressure, high-temperature superheated vapor. The compressor is typically a reciprocating type for smaller domestic plants and is fitted with safety devices like High Pressure (HP) and Low Pressure (LP) cut-outs, and a lube oil low pressure cut-out.