where ( 30 − ta) is the potential convective, ( 42.5 − 0.01Pa) po-tential and evaporative heat transfer given by the constant.
The ASHRAE recommends keeping the percentage of local dissatisfaction below 15%, and the percentage of general thermal comfort dissatisfaction below 10%. As we can see, this PD tends to decrease when the temperature decreases and, consequently, these limiting conditions can be employed to define the optimal conditions for energy saving in the air conditioning systems.
The influence of humidity on thermal sensation may be under dynamic conditions to calculate the PD.