Experimental evaluation of paraffin based phase change material on thermal performance in building

Abstract

The construction industry being the foremost consumer of material and energy resources requires energy savings as well as thermally efficient materials. Extreme hot weather conditions require a substantial amount of electricity consumption for appropriate thermal comfort. This is an economic burden and detrimental for sustainable development unless alternative solutions are developed. Therefore, thermal energy storage systems are thought to be a suitable alternative for efficient and green energy implementation in building design. This thesis investigated tailored thermal mass and heat comfort aspects (thermal management) of newly extracted phase change materials (PCMs) called local paraffin obtained from petroleum as potential thermal energy storage (TES) systems in the context of Iraq. Systematic experimentations were performed in collaboration with the Ministry of Petroleum (Iraq) as the provider of indigenously extracted PCMs to evaluate its thermal performance. Experiments were conducted using three types of local paraffin that are low cost and available as by-products of oil extraction. Three various compositions of paraffin including PCM1 (60% oil + 40% wax), PCM2 (50% oil + 50% wax) and PCM3 (40% oil + 60% wax) were used to determine the suitable mixture for the hot and dry climate environment. The performance evaluation was based on thermal storage for energy conservation via a portable system. This experimental system was simplified as model designs for realizing the full-scale experiment. Experimental results revealed that PCM3 is the best due to its high energy storage capacity. Two identical test rooms were constructed to determine the effect of PCM3 incorporation on heat transfer in the range of 40-44 °C on the roof and walls. The heat flux and temperature distribution inside the room without and with PCM were measured. The room containing PCM3 displayed higher resistance to flow and heat transfer. Furthermore, the effect of PCM installed roof thickness changes on the thermal performance of full scale test room was determined. It was confirmed that the PCM thickness variation in the roof has significant effect on the thermal performance of full scale test room where a higher thickness achieved better thermal performance (lower heat flux penetration and enhanced thermal comfort). Overall, reduced internal heat flux and temperature fluctuations were achieved with PCM3 encapsulation in the test room. The research has established that the local paraffin, (PCM3) with a low thermal conductivity has prospects for the construction industry in terms of its low electrical energy consumption.