TEKNIK PERHITUNGAN SPACE COOLING LOAD DENGAN METODE TETD

Metode TETD

            Perhitungan heat gain pada ruang perkantoran menggunakan metode TETD. Secara ringkas cara perhitungan sebagai berikut:

1.   Atap dan dinding (roofs and walls)

q = A x U x TETD

q = heat flow, Btu per hr

A = Area, ft²

U = Over-all heat transfer coefficient

TETD = Total equivalent temperature difference

     2.     Partisi, ceilling, dan lantai

q = A x U x TD

TD = (t₂ – t₁) = Difference in temperature between the bounding surface, F

     3.      Kaca

q = {A} x {[direct radiation] x [shade factor] + [convection] x [type factor]}

A =Area, ft²

     4.     Manusia (people)

q_s  =  n x sensible heat gain

q_l  =  n x latent heat gain

     q_s  = q sensible

q_l  = q latent

n   = Number of people in space

    5.      Penerangan

q = Watt x 3.4 x Allowance factor

    6.     Ventilasi dan infiltrasi

q_s    =  1.08 x Q x (t_o - t_i)

q_l    =  0.7 x Q x (HR_o - HR_i)

Q    =  Air flow rate, cfm

t_o    =  Outside air temperatur

t_i     =  Room air temperatur

    HR_o =  Humadity ratio of outside air, grains per lb

    HR_i  =  Humadity ratio of room air, grains per lb