Usage of phase change materials towards optimum indoor temperature reduction through cool wall panel

This study aimed to investigate the potential of Phase Change Materials (PCMs) as a passive cooling technology for enhancing energy efficiency and productivity in buildings. A novel composition of inorganic salt hydrates was proposed as a new PCM composite material and evaluated for its thermal performance. Ten different PCM mixtures underwent comprehensive analysis using Differential Scanning Calorimeter (DSC) to assess their thermal characteristics, and the most suitable mixture was selected for incorporation into building materials. Thermal stability and reliability tests were conducted within temperature ranges of 0 °C to 80 °C and 20 °C to 200 °C, respectively. To evaluate the effectiveness of the designed Eutectic PCM in reducing indoor temperature, a series of field experiments were conducted. This involved integrating the PCM into High-Density Polyethylene (HDPE) tiles and applying them to the external surface of concrete wall panels known as Cool Wall Panel (CWP). HDPE was utilized as a matrix to encapsulate the PCM, employing a macro-encapsulation technique called Heat Barrier Tile (HBT) to address leakage and corrosion concerns associated with Ca-based materials. Four types of wall panels were constructed which are Type 1 as the control panel. Type 2: HBT withoxit PCM, Type 3: HBT containing PCM Mixture I, and Type 4: HBT containing PCM Mixture J. Additionally, an Artificial Neural Network (ANN) simulation was employed to validate the experimental data and serve as a predictive model. The DSC test results indicated promising thermal barrier potential in Mixtures I and J, with a temperature range suitable for Malaysian weather conditions. The designed Eutectic PCM demonstrated thermal reliability and a high enthalpy range, remaining stable within a specific temperature limit. Notably, Eutectic PCM (Mixture J) consisting of 98 wt.% CaCl2-6H20, 1.5 wt.% SrCl2-6H20, 0.25 wt.% NaCl, and 0.25 wt.% KCl reduced the supercooling degree by 84.6% to 3.15 °C compared to pure CaCl2‘6H20 (20.45 °C). Experimental results revealed that Type 4 wall panels reduced indoor temperature by 15 °C or 55.3% compared to the non-PCM panel. These experimental findings aligned with the simulation results obtained using the Artificial Neural Network. In conclusion, both the experimental and simulation outcomes provided substantial evidence supporting the potential of the designed inorganic PCM to reduce cooling loads in buildings when applied to building facades. This research offers valuable insights for future implementations.