Effect of window-glass type on solar heat gain and velocity and temperature distributions inside air-conditioned rooms – A conjugate numerical analysis

Abstract

Conjugate mixed-convection numerical analysis is conducted in order to investigate effect of employing different types of window glass on solar heat gain in air-conditioned rooms using mixing air-distribution system. ANSYS Fluent and RNG k-ε turbulence model are utilized. Single- and double-pane clear and tinted window glass are considered with window-to-wall ratio of 0.33. The rate of air change per hour (ACH) is varied in range 5–20. Part of solar radiation absorbed by glass is conducted indoor while solar radiation transmitted through glass heats portion of floor and is released as a heat source to inner space. The numerical model is validated against measurements available under simpler conditions. Results of model application show that airflow pattern and temperature distribution are sensitive to the solar heat gain and, hence, to the type of glass used. It is found that air-conditioning load due to window glass heat gain is reduced by 55% by using double-pane tinted glass compared to using single-pane clear glass. A criterion to distinguish between forced and mixed convection situations in terms of ACH is also developed. In addition, further calculations are made using standard k-ω turbulence model and satisfactory agreement with RNG k-ε model results is obtained.