Document Type : Research Paper
Authors
Department of Mechanical Engineering, College of Engineering, University of Al-Qadisiyah, Al-Qadisiyah 58001, Iraq.
Abstract
This paper presents an experimental study of the effects of polyurethane (PU) capsule position on heat gain in hollow brick walls in real outdoor environments. The experiments were carried out in October 2024 at the University of Al-Qadisiyah, Middle Area Desert, Al-Diwaniyah, Iraq, during an ambient temperature range from 22 to 39 °C and peak solar radiation intensities of (750 W/m²) (horizontally) and [650W/m²] (south-facing vertical). Two identical cubic test cells (1 m × 1 m × 1 m) were built and thermally calibrated to have identical baselines. Two wall configurations were tested: PU capsules in the outer cavity row (external) and in the inner cavity row (internal). The results demonstrate the superior thermal insulation capacity of the outboard position. The maximum surface temperature of the outer wall in the externally insulated condition was 46.7 °C, compared with 45.4 °C for the inner wall, indicating better heat interception by the outer exposed layer (exterior). Internal surface temperatures were 36.0 °C and 37.2 °C at the external and internal positions, respectively (less heat transfer). Indoor ambient temperatures were 33.8 °C with external installation and 34.3 °C with internal installation. The peak heat flux rate on the south wall decreased from 72.2 W/m² (internal) to 58.7 W/m² (external), a 19% decline. These findings apparently demonstrate that if PU capsules are placed in the outer cavity row of hollow brick walls, solar heat can be intercepted successfully before entering the wall mass, thereby improving thermal resistance and reducing cooling requirements for hot-climate buildings.
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