Experimental investigation on biocomposite phase change material-filled bricks for passive temperature regulation in buildings in a hot and humid climate

Space cooling energy demand has surged three times since 1990, in line with the ever-increasing rise in global temperature. Efficient passive building envelopes are always appreciated for regulating indoor temperature, which in turn helps reduce building cooling energy demand. The current study presents the enhancement of brick walls using shape-stabilized phase change materials (PCM) for passive temperature regulation in a small-scale room. The shape stabilization is achieved by incorporating organic PCM into the porous matrix of water hyacinth (WH) biochar. Initially, the thermal behavior of a clay brick containing a centrally embedded 20 mm thick layer of WH-PCM has been studied in a thermal chamber. Following the preliminary results, (1 m × 1 m) wall sections have been constructed using WH-PCM incorporated bricks to identify the optimal position and orientation for WH-PCM application. Three configurations are examined with a 20 mm thick WH-PCM layer placed at an axial distance of 70 mm (Case I), 45 mm (Case II), and 20 mm (Case III) from the outer wall surface. Outdoor experiments have been performed for each configuration of the WH-PCM layer in all four directions over one summer month in a hot and humid climate. Positioning the WH-PCM layer in the middle of the wall (case II), facing west direction, is found to be the most effective in terms of overall inside surface temperature reduction. The maximum temperature and average heat flux reduction are 10.47 % and 76 %, respectively, for case II in the west direction compared to the control wall. The compressive strength analysis shows that the brick with WH-PCM on the middle layer comes under grade 7.5 according to IS 1077: 1992 standards, which falls within the range for building construction. • Developed biocomposite PCM wall for passive thermal management of buildings • Maximum temperature reduction is found in the middle-filled biocomposite PCM brick. • The best temperature reduction with the biocomposite PCM was observed in the westfacing wall. • The compressive strength of the modified brick falls under grade 7.5 of IS 1077: 1992.