Building roof with conical holes containing PCM to reduce the cooling load: Numerical study

• Published in: Energy conversion and management 2011-08, Vol.52 (8), p.2958-2964
• Main Authors: Alawadhi, Esam M., Alqallaf, Hashem J.
• Format: Article
• Language: English
• Subjects: Absorption; Applied sciences; Cooling loads; Energy; Energy use; Energy. Thermal use of fuels; Exact sciences and technology; Frustums; Heat flux; Heat transfer; Heating, air conditioning and ventilation; Indoor; PCM; Phase change material; Rational use of energy: conservation and recovery of energy; Roof insulation; Roofs; Solar heat gain; Technical data: comfort, insulation, loads, etc; Transport and storage of energy
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2011.04.004

► We investigated a roof structure with cone frustum holes containing PCM. ► Different types of PCM and geometries of the PCM are presented. ► The results indicate that the heat flux at the indoor space is reduced by 39%. The thermal effectiveness of a building’s roof with phase change material (PCM) is presented in this paper. The considered model consists of a concrete slab with vertical cone frustum holes filled with PCM. The objective of incorporating the PCM into the roof structure is to utilize its high latent heat of fusion to reduce the heat gain during the energy demanded peak hours, by absorbing the incoming energy through the melting process in the roof before it reaches the indoor space. The thermal effectiveness of the proposed roof-PCM system is determined by comparing the heat flux at the indoor surface to a roof without the PCM during typical working hours. A parametric study is conducted to assess the effects of the cone frustum geometry, and the kind of PCM used. The n-Eicosane shows the best performance among the examined PCMs, and the conical geometry of the PCM container is the best in term of thermal effectiveness. The results indicate that the heat flux at the indoor surface of the roof can be reduced up to 39% for a certain type of PCM and geometry of PCM cone frustum holes.