Expanding Heisler chart to characterize heat transfer phenomena in a building envelope integrated with phase change materials

• Characterizing transient heat transfer phenomena of PCM wallboard.
• Non-dimensional analysis of heat transfer of PCM was conducted.
• Procedure developed to extend Heisler chart to PCM.
• Expanded Heisler chart was validated by the analytical solution.

Building envelope integrated with phase change material (PCM) can provide thermal energy storage (TES) distributed in its entire surface area and inhibit the need for enhanced thermal mass in lightweight buildings. Selecting the most appropriate PCM wallboard based on its thickness and thermo-physical properties is the main challenge in the design of net-zero energy buildings and high performance buildings; yet, there is a lack of an appropriate design tool. To develop a design tool, characterizing transient heat transfer phenomena of wallboards impregnated with PCM during charging procedure is required. Accordingly, this study focuses on the characterizing heat transfer of PCM wallboards, and to identify the influential parameters on the charging procedure of a PCM wallboard. The non-dimensionalized analysis was conducted, and the dimensionless numbers influencing the thermal behavior of a PCM wallboard were identified. Moreover, the correlations between the dimensionless parameters and the performance of the PCM wallboard were determined through a comprehensive parametric study. Consequently, a procedure was developed to expand Heisler chart application to study thermal behavior of PCM wallboards.