The sky temperature in net radiant heat loss calculations from low-sloped roofs

Abstract The results of calculated and measured sky temperatures for a horizontal surface in clear night-time sky conditions are compared and discussed. In the case of large city areas (atmospheric pollution) the sky temperature may be about 10°C higher than the one calculated according to Swinbank's formula. The paper presents a quantitative analysis concerning the influence of the sky temperature values variations on net radiant heat loss and the heat balance of the low-sloped roofs.