Capric acid and palmitic acid eutectic mixture applied in building wallboard for latent heat thermal energy storage

The paper aims: (1) preparation of the phase change gypsum wallboard as novel phase change wallboard (PCW) incorporating with the eutectic mixture of capric acid (CA) and palmitic acid (PA) for latent heat thermal energy storage; (2) determination of thermal properties and thermal reliability of prepared PCW using differential scanning calorimetry (DSC) technique; and (3) estimation of thermal performance of PCW by preparing a simple test cell. Maximum CA/PA eutectic mixture as phase change material absorbed in PCW was about 25 wt% of total weight. No leakage of the mixture from PCW was observed after 5000 thermal cycling. The melting and freezing temperatures and latent heats of PCW were measured as 22.94 and 21.66°C, 42.54 and 42.18 J/g, respectively by DSC analysis. These properties make it functional as TES medium, which can be applied to peak load shifting, improved use of waste heat and solar energy as well as more efficient operation of heating and cooling equipment. In addition, PCW has good thermal reliability in terms of the changes in its thermal properties after accelerated 1000, 2000, 3000, 4000, and 5000 thermal cycling. Use of such PCW can decrease indoor air fluctuation and have the function of keeping warmth to improve indoor thermal comfort due to absorption of heat in conjunction with melting of the eutectic mixture.