Room area 20 m2, height 3m. How much heat is needed to heat the air in the room from 4 degrees to 20 degrees.

Given: S (room area) = 20 m2; h (room height) = 3 m; t1 (initial air temperature) = 4 ºС; t2 (end temperature) = 20 ºС.

Constants: ρv (air density at std. Conv. For gases (t = 0 ºС)) = 1.292 kg / m3; Sv (specific heat capacity of air) = 1005 J / (kg * K).

The heat expended for heating the air in the room is calculated by the formula: Q = Sv * m * (t2 – t1) = Sv * ρw * V * (t2 – t1) = Sv * ρw * S * h * (t2 – t1).

Calculation: Q = 1005 * 1.292 * 20 * 3 * (20 – 4) = 1246521.6 J ≈ 1.25 MJ.