Fully integrated numerical design tool to assess the thermal performance of phase change materials (PCM) in the built environment

Abstract

Thermal energy storage with phase change materials (PCM) is a promising candidate to promote resource sustainability in buildings. The intelligent selection and usage of a PCM within the structure of a building poses a challenging engineering task due the highly dynamic nature of occurring heat transfers. This work features a step-by-step FEM modeling guideline to assist the design of building structures by means of a 1D heat conduction scheme. The phase change functionality is based on the apparent heat capacity method and extended by ordinary differential equations to account for the thermal hysteresis of materials with different melting and freezing temperatures. The set of equations is solved alongside with logical expressions representing a thermostat functionality to assess the external energy demand. Two proof-of-concept examples for PCM usage in typical Swiss and Greek wall structures are given.