Thermal Performance of a Triple-Glazed Exhausting and Ventilating Airflow Window System

Abstract

The thermal performance and optimum design of a triple-glazed exhausting and ventilating aire ow window system arestudied numerically using a e nitevolume method. Exhausting and ventilating aire ow rate, solarinsolation, and aspect ratio are identie ed as important governing parameters. Effort is directed toward the reduction in space cooling and heating load. It is found that both space-heat gain and space-heat loss are reduced considerably by increasing the exhausting and ventilating aire ow rate. The optimum aire owrate(Reynolds number) and aspect ratio are found to be about 600 and 0.05, respectively. Comparisons between the aire ow window system and the enclosed window system are madequalitatively and quantitatively. The aire ow window system with zero Reynolds number corresponds to the enclosed window case. The present aire ow window model can be used year round, as an exhausting aire ow type in summer and as a ventilating aire ow type in winter. Nomenclature A = area of glazing, m 2 C = heat capacity, kJ/m 3 ¢K Cp = specie c heat, kJ/kg ¢K c = clearance, m Gr = Grashof number g = gravitational acceleration, m/s 2 H = height of the window, m h = convective heat transfer coefe cient, W/m 2 ¢ ± C It = solar insolation per unit area, W/m 2 k = thermal conductivity, W/m ¢K