Carnot engine efficiency is a function of_______________________?
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Answer: E. temperatures of source and sink
Explanation
Carnot engine efficiency is derived exclusively from the absolute temperatures of the thermal source and sink. Mathematical formulas for Carnot efficiency contain only the high and low absolute temperature variables. The nature of the working fluid or mechanical design does not affect the ideal thermal efficiency limit. French physicist Sadi Carnot proved that maximum engine efficiency depends solely on external temperatures. The efficiency equals one minus the ratio of the sink temperature to the source temperature. Kelvin temperature scale must be used to calculate Carnot efficiency values accurately in engineering.
Power plant designers raise boiler operating temperatures to improve the Carnot efficiency of the plant. Environmental cooling water temperatures set the lower sink temperature limit for thermal power stations. Understanding this principle shows why increasing heat source temperature is vital for better fuel economy. Option A is false because ideal Carnot efficiency is independent of the chosen working fluid. Option B is incorrect since engine design details only affect how closely a real engine approaches the limit. Option C is wrong because engine physical size has no direct mathematical impact on theoretical efficiency.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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