h = ΔQ / A x ΔT 

Keterangan:
h     = Thermal Admittance, heat transfer coefficient, W/(m2K)
ΔQ  = heat input or heat lost, W
A    = heat transfer surface, m2
ΔT  = difference in temperature between the solid surface and the adjacent air space.

Time Lag (Retardation time) (hour)

t retadation = d^2/(3600 x 4 x DT)

Keterangan:
t retardation = time lag
d                  = thickness (m)
DT               = Thermal diffusion


DT = λ /( ρ x C )

Keterangan:
λ    = thermal conductivity (W/m.K)
ρ    = density (kg/m3)
C   = specific heat capacity (J/kg.K)

sumber : http://www.eyoungindustry.com/uploadfile/file/20161225/20161225140805_22599.pdf

WSc = 0.5(DBT-27.2+0.56(RH-60)/10)

WSc = Standar kebutuhan kecepatan angin (m/s)
DBT = Dry bulb temperature (temperatur ruangan)
RH   = Relative Humidity