Numerical Simulation of the Influence of Air Space Thickness in Heat Transfer of a High-Performance Glazing System

The heat transfer on solids and fluids of a high-performance glazing system was numerically investigated. This proposed glazing system is employed for the renovated building or the low-energy house for the purpose of improving thermal efficiency and energy preservation. The first model aims to examine the influence of the distance between two glazing (also defined as the air space thickness) in the heat flux by simulation using the COMSOL Multiphysics programme. This step helps determine the critical or possible optimum thickness of the space filled with air in the glazing system. Next, the total heat losses of the three-dimensional glazing system were calculated regarding the changes in ambient temperature based on the actual data collected in Budapest, Hungary. Results showed that the heat flux on the internal side of the glazing system decreased as the air space thickness increased from 50 to 150 mm and was almost stable from 200 to 300 mm. Hence, the range of 200–300 mm could be a feasible distance for the window system manufacture. A half reduction of the total heat losses relating to the increase in the thickness of air space was also explored as the actual temperature changed over 4416 h in wintertime. Overall, the glazing system numerically modelled in the present work proved a contribution to a reduction in energy consumption in buildings.