Second law of thermodynamics

Second Law of Thermodynamics

• Units and Variables

  • e - thermal efficiency
  • W - work done by a heat engine, in Joules
  • COP - coefficient of performance
• $e=1-\frac{\left|Q_c\right|}{\left|Q_h\right|}$
• $W=\left|Q_h\right|-\left|Q_c\right|$
• $\text{COP (heating)}=\frac{\left|Q_h\right|}{W}$
• $\text{COP (cooling)}=\frac{\left|Q_c\right|}{W}$

• Carnot Engines

  • $\frac{\left|Q_c\right|}{\left|Q_h\right|}=\frac{T_c}{T_h}$
  • $e_C=1-\frac{T_c}{T_h}$
  • $\text{COP (heating)}=\frac{T_h}{\mathrm{\Delta T}}$
  • $\text{COP (cooling)}=\frac{T_c}{\mathrm{\Delta T}}$
• $e=1-\frac{1}{{\left(V_1/V_2\right)}^{\left(\gamma -1\right)}}$