(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

On a hot day a house is kept cool by an air conditioner. The outside temperature is 32°C and the inside temperature is 21°C. Heat leaks into the house at the rate of 9000 kcal/h. If the air conditioner has the efficiency of a Carnot engine, what is the mechanical power that it requires to hold the inside temperature constant?

3. The attempt at a solution

e= 1-294/305 = 0.036066

e=W/Q_{H}

Power = 9000 kCal/hour --> 37656000 J/hour --> 10460 J/s

.036066=W/10460 ---> W (really power)=377.426 J/s

This problem seems pretty straightforward...but the back of the book has an answer of 390 W, which is ~13 more J/s than my answer, so I must have made a mistake....yet there are only two equations, and one conversion! Is this a rounding error from the book?

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# Homework Help: Thermodynamics - Carnot efficiency

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