Application of PCM for radiant heating of residential buildings in Canada towards achieving nearly zero energy buildings

The purpose of this research was to investigate the effect of using a thermal energy storage system consisting of an active layer inside the walls, embedded in a layer of PCM, for a residential building in Toronto on the annual savings of heating energy. The energy of the active layer is supplied by a solar collector integrated with a thermal energy storage tank, and the PCM helps to regulate the temperature of the water flowing inside the active layer pipes during the times when its temperature starts falling. The modeling and simulation of the entire system were performed in TRNSYS software. A parametric study was also conducted, focusing on the impact of the piping configuration layout on its thermal performance for energy savings. The obtained results indicate that using only an active layer inside each wall, with a diameter of 3 cm and spacing of 11 cm, would result in a 65 % annual energy saving. Additionally, embedding these pipes in a layer of PCM with a thickness of 12 cm can lead to further annual energy savings of 27 %. This means that using this system for a building in Toronto can achieve annual heating energy savings of 92 %, equivalent to a reduction from 14,400 MJ to 1012 MJ throughout a year. Furthermore, a cost analysis of the proposed model over its 25-year lifespan was conducted, showing a payback period of 22 years. • The study examines thermal energy storage with PCM for near-zero energy residential heating in Toronto. • Using an active layer alone saved 65 % of annual heating energy. • Adding a 12 cm PCM layer further reduced heating energy by 2 %, achieving a 9 % total savings. • Optimal active layer setup: 3 cm diameter pipes, 11 cm spacing, improving energy savings and temperature control. • The system kept indoor temperatures comfortable, cutting heating load during cold months. • Proposed model has a payback period of 22 years for a 25-year lifespan.