Analytical Optimization of Key Design Parameters of Phase Change Materials Used in Passive Building Envelopes

Phase change materials have been widely used in energy efficient buildings for thermal energy conservation. Determination of the optimal phase change temperature and melting enthalpy is important to achieve the best energy saving performance. This paper presented a novel method to determine the optimal phase change temperature and melting enthalpy in a passive solar house based on analytical analysis. It was showed that the optimal phase change temperatures of PCMs in Copenhagen and Madrid are 23 °C and 22.6 °C. And the optimal melting enthalpy of the given house is 735.4 MJ/m3 for the whole winter. In addition, sensitivity analysis was applied to determine the most influencing fators to the optimal phase change temperature and melting enthalpy. The results showed that the most influencing factors are ACH and dimensionless thermal resistance number. The proposed method can offer guidelines to determine the optimal phase change materials in given buildings.