Steam Heating Air

Steam is often used to heat air. Steam condensing rate for air heating equipment can be calculated as

m_s = q dt c_p ρ / h_e                               (1)

where

m_s = rate of condensation, steam consumption (kg/s)

q = volumetric air flow rate (m³/s)

dt = temperature difference in air flow (^oC)

c_p = specific heat of air (kJ/kg ^oC)

ρ = density air (kg/m³)

h_e = specific enthalpy of evaporating (condensation) steam (kJ/kg)

Example - Heating Air with Steam

1 m³/s of air is heated from 10 ^oC to 30 ^oC with steam condensing at atmospheric pressure. The steam consumption can be calculated as

m_s = (1 m³/s) ((30 ^oC) - (10 ^oC)) (1.0 kJ/kg ^oC) (1.204 kg/m³) / (2257 kJ/kg)

     = 0.011 kg/s