Heat transfer through a double pane window with an insulation screen open at the top

The paper presents research of heat transfer through a double pane window with a screen and a siphon which form a semi-open cavity. Several operation modes of such devices as part of a transparent building envelope are shown, as well as the basis for mathematical and numerical CFD modeling with emphasis on conjugate heat transfer involving diffusion, convection and radiation. Gebhart's method was used for radiation heat transfer. The PHOENICS code was used for CFD, with an additionally produced program code for the calculation of Gebhart factors and database formulation. Numerical results were validated with a series of experiments in which temperatures, heat fluxes and flow visualization were observed. The visualization technique was used for low fluid velocity measurements. After validation of the numerical code, a parametric study for such elements of the building envelope was evaluated with a range of boundary conditions based on the expected meteorological conditions. A modified form of dimensionless radiation number was used for empirical Nu number correlation.