Optimal design method for lightweight buildings to minimize the cooling load with phase change materials using orthogonal experimental design

Abstract

This study presents an investigation of the annual cooling load in buildings by analyzing the influence of parameters of phase change materials (PCMs) integrated into the envelopes of the buildings. For the use cases, well-known Cases 600 and 650 of ASHRAE Standard 140 were considered. We modified vertical walls of the use cases incorporating various PCM layers. The impact of various factors of PCM layers in four climates was assessed. These factors were the thickness, melting temperature, latent heat of fusion, density, specific heat capacity, and thermal conductivity. The results showed that the variation of the density, latent heat of fusion, and the thickness of PCMs had a high impact on the reduction of the annual cooling energy. However, the level of thickness, latent heat of fusion, and density stuck in the maximum value, whereas the level of thermal conductivity and specific heat capacity stuck in the minimum value. Generally, during the global and multi-objective optimization problems, these parameters may be excluded from the variable settings except for thickness whereby the penalty function can be set. The general thermodynamic pattern of the results concludes that buildings with lightweight envelopes require as much heat storage as possible preventing it from the flow of heat to the surrounding.