Experimental and numerical analysis of flow and heat transfer in double skin facade cavities

Abstract

In this study, airflow and heat transfer in a double skin facade (DSF) cavity were examined numerically and experimentally under natural and forced flow conditions. An experimental setup was constructed i the laboratory environment. Experiments were performed for two different DSF's airflow modes; buffer zone and external air channel. These experiments vere conducted with and without a solarsimulator integratrd t the system. Furthermore, the effect of pressure drop elements in the cavity of DSF were analyzed experimentally. After the numerical results (CFD and nodal network) were verified with experimental measurements, dimensionless heat transfer correlations were developed for the natural and forced convections. As a result, an extensive experimental data set was obtained for different working conditions of DSF. So, the dimensionless pressure loss coefficients were calculated experimentally based on the geometric configuration of the pressure drop elements in the cavity. In natural convection, with Rayleigh numbers ranging from 8.59*109 to 1.41*1010 and the increasing tendency of the average Nusselt numbers from 142.6 to 168.8 were shown. A correlation for a cavity characteristic length of 0.116 was constructed to evaluate the heat flux. In forced convection, another dimensionless correlations weredeveloped to predict the heat transfer by using. Nusselt numbers with in the Reynolds numbers ranging from 28000 to 56000 for a DSF with an external airflow mode. These correlations could be used for different characteristic length ranged betwen 0.1 and 0.16. These correlations were used for the energy performence of DSF applications for different directions and climatic zones in Turkey and compared with the single skin facede.