Glass cover temperature and top heat loss coefficient of a single glazed flat plate collector with nearly vertical configuration

An empirical relation for glass cover temperature of a single glazed flat plate collector for angle of tilt 60–90° is proposed. Values of glass cover temperature obtained from empirical relation have been used for computation of top heat loss coefficient of collector. Analytical equation has been employed for estimation of top heat loss coefficient, Ut. The range of variables covered in the present analysis is 20 °C to 150 °C for absorber plate temperature, 0.1–0.95 for absorber coating emittance, 20–50 mm for air gap spacing, 60–90° for collector tilt, 5–30 W/m² K for wind heat transfer coefficient and -10 °C to 40 °C for ambient temperature. The maximum absolute error in values of Ut is within two percent, in comparison to values obtained by numerical solution of heat balance equations, over the entire range of variables.