8. Selection of Phase-Change Material for Building Envelope by Qualitative Decision-Support Analysis

The characteristic structure materials are frequently classified jointly in the course of many construction design steps to form what is known as the building envelope. The selection of proper building and insulation materials is one of the most significant responsibilities in the building project’s design improvement step. This determination will have a substantial effect on the building’s efficiency in terms of numerous design attributes. Finding trade-offs that satisfy a variety of efficiency criteria can help improving energy efficiency of the building design. Correct judgments are critical for optimizing building performance in terms of many performance characteristics such as thermal condictivity, density, specific mass, and so on. Although the final result cannot be completely seperated from the remaining project steps, using decision making procedures can help making this a more sensible conclusion. With this aim, MCDM approaches are commonly used for the efficient building envelope material choice. The analytic hierarchy process has been utilized to identify and evaluate proper phase-change materials for comfort applications in buildings. The temperature of phase-change for phase-change materials utilized in this system is from 21 to 28 °C. Five criteria were used in this analysis: latent thermal capacity, temperature of phase-change, solid-phase density, material thermal conductivity, and specific thermal capacity. A variety of phase-change materials can be used for comfort purposes based on certain criteria. The goal of this research is to select the best phase-change material for building envelope applications utilizing the AHP methodology. This method involves determining the evaluation criteria and comparatively evaluating pairs of criteria to find the relative importance of each criterion. Consequently, each phase-change material is evaluated for their performance based on each of these criteria and assigned a total score to determing the optimum material. The aim is to obtain the most efficient phase-change material for building envelope by determining the weights of convenient phase-change materials to insulate the building external walls using only the phase-change materials’ technical requirements and criteria.