Frequently Asked Questions about the ASTEC Systems

18. What are the mathematical equations used to calculate heat transfer by (a) conduction, (b) convection, and (c) radiation?

Conduction
q" = k (T₁- T₂) / L = (T₁- T₂) / Σ R

Convection
q" = h_FILM(T₂-T₃)

Radiation
q" = εσ(T⁴₂ – T4₃)

Where,
T1= roof surface temperature
T2= roof underside temperature
T3= given room air temperature
hfilm= 5.67 (for still air above and under the roof)
σ= (sigma) 5.67 x 10^-8 [Stefan-Boltzmann]

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