Experimental and numerical investigation of developing correlations for convective heat transfer coefficient for internal room surfaces considering ceiling diffusers effects

An experimental and numerical study analyzed convective heat transfer in a room. The experiments involved measuring temperatures in a room with a window and a diffuser placed in different positions. Numerical simulations modeled a room with windows of varying sizes on the south wall, slot diffusers, and radiators. This research aims to address gaps in calculating convective heat transfer coefficients for innovative window designs by proposing new correlations to improve the accuracy of cooling and heating load predictions. Solar radiation data from Tabriz City was incorporated. Key parameters included volumetric inlet flow rate, diffuser inlet angle, and window-to-wall ratio. CFD simulations employed the SIMPLE algorithm with second-order discretization and the standard K-epsilon turbulence model. The findings indicate that the reference temperature strongly influences the results. Supply temperature consistently showed a higher convective heat transfer coefficient compared to the reference temperature, usually defined as the average room temperature. Moreover, the window-to-wall ratio emerged as the most critical factor, with larger windows leading to a notable increase in the convective heat transfer coefficient.