The Impact of Air Gap Width on the Free Thermal Load in the Trombe Wall Contains a Phase Change Material

The objective of the present study is to investigate the effect of the air gap on the amount of mass flow rate and the ratio of energy storage in the thermal storage system containing a Trombe wall and that is through conducting experiments inside a room with dimensions of (1.5*1*1.5) m3, made of PVC sandwich insulation panel. The room contains a thermal wall of a dimension of (0.96*1.44*0.1) m3 made from a wood frame and contains 99 capsules of industrial wax of (6) cm diameter and (9.6) cm length, distributed by matrix form of (11*9). The wall is supported by four iron guides from both sides to move it easily in a distance of (10 to 35) cm from the glass cover in the south direction. The experiments have been conducted under real weather conditions of December 2016 for Kirkuk city, and this study included six widths of the air gap, arranged from (35 to 10) cm with steps of 5cm each. the results showed that the width of the air gap has a great effect on the mass flow rate through the air gap and energy incoming to the thermal system, where the best case for both factors was obtained at (b=35cm), and the max energy storage has been obtained at (b=15cm) and is about 45% of energy incoming to the system at the experiments of sunny days