What is typically the COP value in a vapor compression cycle__________________?
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Answer: B. always more than unity
Explanation
The coefficient of performance in a vapor compression cycle is always greater than unity because heat extracted exceeds work. Refrigeration systems pump heat by consuming a relatively small amount of electrical work compared to the massive thermal energy moved. This ratio of useful cooling effect to compressor work input mathematically yields numerical values consistently exceeding one. Coefficient of performance measures thermodynamic efficiency by dividing the refrigerating effect by the required compressor work. Energy conservation principles confirm that total heat rejected equals the sum of cooling effect absorbed and compressor work added. Vapor compression cycles achieve high COP values because latent heat of vaporization is significantly larger than compression work.
Option A always less than unity describes machines like electric heaters where thermal output equals or exceeds electrical input. Option C equal to unity implies no thermodynamic advantage over direct electrical resistance heating, which contradicts refrigeration physics. Option D any one of the above ignores the fundamental thermodynamic reality that vapor compression COP always exceeds one.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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