Effects of shape-stabilized phase change materials in cementitious composites on thermal-mechanical properties and economic benefits

Abstract

• The effects of PCMs to save building energy consumption was investigated. • Physical-thermal-mechanical testing and cost analysis were conducted. • Energy saving efficiency was calculated via computational modeling. • Findings infer the potential application of coconut oil as an engineered PCM. Phase change materials (PCMs) have been utilized to improve the thermal properties of cementitious composites by using their latent heat capacity. Applying them to building components can reduce their heating and cooling loads through energy absorption during the phase change period. The shape-stabilized method using porous lightweight aggregates can prevent PCM leakage during the phase transition process. While many attempts have been made to develop and improve shape-stabilized PCM composites to achieve a high level of energy savings, their economic benefits have not been fully investigated, as most analyses are based on initial material costs with a limited linkage of their thermal-mechanical properties. This study used an integrated experimental-computational method to evaluate the effects of different PCMs in building components by considering the core thermal-mechanical properties with an economic benefit analysis. Toward that end, two different PCMs (PureTemp® and coconut oil) were selected to fabricate Thermal Energy Storage Aggregates (TESA) using the vacuum impregnated method: TESA-P (with PureTemp®) and TESA-C (with coconut oil). The thermal-mechanical properties were experimentally determined and used for building energy simulation for a typical small office in Houston, Texas. The cementitious composites incorporated with PCM showed lower thermal conductivity and heat transfer than the non-PCM specimens. The TESA-P specimens showed a more prolonged time lag and better energy-saving performance than the TESA-C specimens due to better thermal properties of PCM itself. In contrast, the costs of TESA-C applications could be less with a shorter pay-back time. The findings of this study infer the potential application of coconut oil as an engineered PCM in building construction.