Refrigeration Capacity from Enthalpy Difference
Refrigeration effect equals mass flow times the enthalpy gained across the evaporator.
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Enthalpy values must come from verified refrigerant property tables for your refrigerant.
Formula
- Q = ṁ × (h₂ − h₁)
Variables
- ṁ
- — Refrigerant mass flow (kg/s)
- h₁
- — Enthalpy entering evaporator (kJ/kg)
- h₂
- — Enthalpy leaving evaporator (kJ/kg)
Example calculation
0.05 kg/s × (405 − 250) kJ/kg = 7.75 kW ≈ 2.2 tons.
Practical HVAC use
Teaching the cycle on a P-h diagram and checking published performance data.
Common mistakes
- Reading enthalpy from a chart for a different refrigerant.
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