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Key Equations

Result of energy conservation W=QhQcW=QhQc
Efficiency of a heat engine e=WQh=1QcQhe=WQh=1QcQh
Coefficient of performance of a refrigerator KR=QcW=QcQhQcKR=QcW=QcQhQc
Coefficient of performance of a heat pump KP=QhW=QhQhQcKP=QhW=QhQhQc
Resulting efficiency of a Carnot cycle e=1TcThe=1TcTh
Performance coefficient of a reversible refrigerator KR=TcThTcKR=TcThTc
Performance coefficient of a reversible heat pump KP=ThThTcKP=ThThTc
Entropy of a system undergoing a reversible process at a constant temperature ΔS=QTΔS=QT
Change of entropy of a system under a reversible process ΔS=SBSA=ABdQ/TΔS=SBSA=ABdQ/T
Entropy of a system undergoing any complete reversible cyclic process dS=dQT=0dS=dQT=0
Change of entropy of a closed system under an irreversible process ΔS0ΔS0
Change in entropy of the system along an isotherm limT0(ΔS)T=0limT0(ΔS)T=0
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