Basic Air Conditioning Processes
2. Sensible Cooling and Heating
When air is heated or cooled sensibly, that is, when no moisture is added or removed, this process is represented by a horizontal line on a psychrometric chart.
For sensible heating:
The amount of heating input to the air approximates to;
H1-2 = m x Cp x (t2 - t1)Or more accurately from psychrometric chart:
H1-2 = m x (h2 - h1)For sensible cooling:
The amount of cooling input to the air approximates to;
H2-1 = m x Cp x (t2 - t1)Or more accurately from psychrometric chart:
H2-1 = m x (h2 - h1)where: H = Heat or cooling energy (kW)
m = mass flow rate of air (kg/s)
Cp = Specific heat capacity of air, may be taken as 1.01 kJ/kg degC.
t = Dry bulb temperature of air (oC)
h = specific enthalpy of air (kJ/kg)
found from psychrometric chart.