Cycle Parameters
Operating Mode
Refrigerant
Evaporator Temp T_evap5 °C
Condenser Temp T_cond45 °C
Superheat SH5 K
Subcooling SC5 K
Compressor Efficiency η_s0.75
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COP Heating
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COP Cooling
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Comp. Work W [kJ/kg]
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Heat Load Qh [kJ/kg]
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Carnot COP
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2nd-Law Eff. η_II
P-h Mollier Diagram
COP vs Condenser Temperature
Key Equations
Vapor compression cycle:
$$\text{COP}_h = \frac{Q_h}{W} = \frac{h_2 - h_4}{h_2 - h_1}, \quad \text{COP}_c = \frac{Q_c}{W} = \frac{h_1 - h_4}{h_2 - h_1}$$Carnot COP (heating): $\text{COP}_{Carnot} = \dfrac{T_h}{T_h - T_c}$ (absolute temperatures)
Second-law efficiency: $\eta_{II} = \text{COP}_{actual} / \text{COP}_{Carnot}$
Applications: Equipment selection for HVAC systems (rated COP pre-check), data center thermal management, industrial refrigeration process design, and building energy simulation initial estimates.