The effective sky temperature: an enigmatic concept

• Published in: Heat and mass transfer Vol. 47; no. 9; pp. 1171 - 1180
• Main Authors: Gliah, Omemah, Kruczek, Boguslaw, Etemad, Seyed Gh, Thibault, Jules
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.09.2011; Springer
• Subjects: Analytical and numerical techniques; Applied sciences; Devices using thermal energy; Earth, ocean, space; Energy; Energy. Thermal use of fuels; Engineering; Engineering Thermodynamics; Exact sciences and technology; External geophysics; Fundamental areas of phenomenology (including applications); Heat and Mass Transfer; Heat exchangers (included heat transformers, condensers, cooling towers); Heat transfer; Industrial Chemistry/Chemical Engineering; Meteorology; Original; Physics; Radiative transfer. Solar radiation; Thermodynamics; Emissivity; Heat Transfer Coefficient; Plate Temperature; Convective Heat Transfer Coefficient; Heat Balance Equation; Steam condenser; Dew point; Experimental study; Water vapor; Condensation; Modeling; Plate; Inverse problem; Direct problem; Meteorological station; Radiative transfer; Heat transfer; Meteorology
• ISSN: 0947-7411; 1432-1181
• DOI: 10.1007/s00231-011-0780-1

To properly simulate the condensation process and design a water recovery system from condensation of atmospheric water vapour on a surface maintained below the dew point by radiative heat loss from the surface to night sky, an accurate estimation of the effective sky temperature is required. To estimate the effective night sky temperature, an experimental system consisting of a series of metal plates embedded on a heat transfer panel, a weather station and a control system was used. The results obtained from theoretical analyses and preliminary experiments are presented and discussed. A special emphasis is given to a mathematical solution of the system of equations that need to be solved to obtain the effective sky temperature. It is shown that although the system of equations works well for the direct heat transfer problem, there is a serious difficulty to solve the inverse heat transfer problem to retrieve the desired parameters.