In domestic and commercial refrigerators, the temperature differential maintained between the evaporating refrigerant and the cooled medium should be_________________?
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Answer: B. as low as possible (3 to 11°C)
Explanation
Refrigerators maintain a low temperature differential between evaporating refrigerant and cooled medium. A small temperature difference keeps the required evaporating pressure and temperature as high as possible. Minimizing temperature lift improves overall compressor volumetric and energetic efficiency. Evaporating temperature determines the suction pressure required by the compressor. Heat transfer rate depends directly on the temperature difference across the evaporator coil. Larger heat transfer surface areas allow lower temperature differences while maintaining capacity.
Commercial walk-in coolers use large evaporator coils to maintain high humidity and efficiency. Supermarket display cases require careful temperature differential control to preserve frozen foods. Optimizing evaporator temperature reduces electrical power consumption in commercial refrigeration systems. High temperature differences of twenty-five degrees degrade compressor efficiency and COP. Zero temperature differential would stop heat transfer entirely because driving force requires delta T. Unrestricted arbitrary values cause inefficient system operation and poor temperature control.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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