Thermodynamics energy efficiency

AI Thread Summary
The discussion revolves around calculating the maximum and actual efficiency of a nuclear power plant generating thermal energy. The maximum possible efficiency is calculated using the formula emax = 1 - (Tc/Th), yielding a value of 0.53. The actual efficiency is derived from the work output divided by the heat input, resulting in a value of 0.65, which exceeds the maximum efficiency. This discrepancy raises questions about the calculations, particularly regarding the correct interpretation of energy input and output. The focus remains on understanding the principles of thermodynamics as they apply to energy efficiency in nuclear power generation.
donkey11
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Homework Statement


Each second, a nuclear power plant generates 2000 MJ of thermal energy from nuclear reactions in the reactors core. This energy is used to boil water and produce high pressure steam at 573 Kelvins, the steam spins a turbine, which produces 700 MJ of electric power, then the steam is condensed and water is cooled to 303 kelvins before starting cycle again.
a) maximum possible efficiency of plant?
b) plant's actual efficiancy?



Homework Equations


emax= 1 - (Tc/Th)
e= what you get/ what you pay



The Attempt at a Solution



a)emax= 1- (303/573) = 0.53
b) e= work out/Qh = Qh-Qc/Qh = 1300/2000 = 0.65
but this is larger then my max!
 
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Shouldn't the plant's efficiency be: 700/2000 ?

The electric power produced is 700MJ. That's what you get. What you pay is 2000 MJ.
 
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