Thermal Behaviour Analysis and Cost-Saving Opportunities of PCM-Integrated Terracotta Brick Buildings

Abstract

Buildings contribute greatly to global energy use and consumption. The energy consumption of buildings is significant due to the integration of heating, ventilation, and cooling systems. Evidently, the utilization of phase change materials (PCMs) in building design can adequately reduce air-conditioning costs of buildings by diminishing external heat gains and losses. Moreover, the adoption of natural, eco-friendly, and cost-effective materials, such as terracotta bricks, can be valuable from an environmental point of view. This paper intends to assess the air-conditioning cost-saving potential of several PCM stuffed terracotta brick configurations. In that respect, the encapsulated PCMs were filled in the hollows of terracotta bricks. For the aims of this study, five different types of PCMs were considered, in relation to the thermophysical properties of their solid and liquid state (OM18: organic mixture, HS22: hydrated salt, OM29, OM32, and OM37). In addition, three PCM-stuffed terracotta brick configurations were examined with reference to the number of the PCM layers (PCMTB-A with one PCM layer, PCMTB-B with two PCM layers, and PCMTB-C with three PCM layers). Therefore, fifteen PCM-stuffed terracotta brick configurations were analysed numerically, related to environmental conditions that refer to two different scenarios in India (hot dry and composite climates). Results have unveiled that the OM32 PCM assemblies have shown better thermoeconomic performance compared to the other types of PCM. With respect to the most advantageous number of PCM layers, the evidence of this analysis has exposed that the PCMTB-C case has shown the highest annual air-conditioning cost-savings and the highest yearly carbon emission mitigations in both climates (Ahmedabad and Lucknow). In hot-dry climates, the PCMTB-C with OM32 PCM exhibited the highest annual air-conditioning cost-saving ($ 74.7), the highest annual carbon emission mitigation (1.43 ton/kWh), and the moderate payback period (22.5 years) compared to the other cases. To conclude, the findings of this study suggest a suitable way to improve the decision-making process of building design, while bridging the performance gap in terms of energy efficiency and sustainability.