To attain a high coefficient of performance, the compressor operating pressure ratio should be_______________?
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Answer: B. low
Explanation
To attain a high coefficient of performance, the compressor operating pressure ratio across the system should be kept low. A low pressure ratio minimizes the specific work input required by the compressor to achieve the desired refrigeration effect. Since coefficient of performance is the ratio of refrigeration effect to compressor work, minimizing work directly increases efficiency. Coefficient of performance measures the energetic efficiency of refrigeration and heat pump systems operating on thermal cycles. Compressor power consumption increases rapidly as the pressure difference between evaporator and condenser widens. Thermodynamic cycle analysis proves that minimizing compressor work input optimizes overall system operating economy.
Option A high pressure ratio increases compressor work input severely, resulting in a low coefficient of performance. Option C optimum is a vague term, whereas thermodynamic principles prove that lower pressure ratios strictly yield higher efficiency. Option D any value ignores fundamental thermodynamic laws governing compressor work and refrigeration cycle efficiency.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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