The Carnot cycle can be shown to be the most efficient thermodynamic cycle for g
ID: 1483384 • Letter: T
Question
The Carnot cycle can be shown to be the most efficient thermodynamic cycle for given temperatures. How efficient would a Carnot heat engine be operating between reservoirs at 20 degree C and 500 degree C? This coule be something like a power plant. What would the coefficient of performance be for a Carnot refrigerator operating between rtservoirs at 20 degree C and 35 degree C? Thus could be something like an air conditioner If the low temperature reservoir is at 20 degree C, how high would TM have to be to have a Carnot efficiency of 90%?Explanation / Answer
(a) Efficiency, = 1 - (Tc/Th) = 1 - [(273 + 20) / (273 + 500)] = 0.62
(b) COP = Tc / (Th - Tc) = (273 + 20) / (35 - 20) = 19.53
(c) Efficiency = 0.9 = 1 - [(273 + 20) / Th]
=> Th = 293 / 0.1 = 2930 K