A living room has a rectangular floor (width 3.5 m, depth 4.8 m) and a height of 2.8 m. Underfloor heating keeps the base area 1 at a constant temperature ϑ 1 = 29 ◦C. One of the narrow side walls...

A living room has a rectangular floor (width 3.5 m, depth 4.8 m) and a height of 2.8 m. Underfloor heating keeps the base area 1 at a constant temperature ϑ₁
= 29 ◦C. One of the narrow side walls (3.5 m by 2.8 m) is the external wall and has been built into a window, the temperature of which is ϑ₂
= 17 ◦C. The ceiling and the other walls can be considered as (adiabatic) reradiating walls. All surfaces are grey Lambert radiators with ε = 0.92. Determine the heat flow transferred by radiation from the floor to the external wall.