Designing building envelope with PCM wallboards: Design tool development

While space conditioning load contributes largely in grid critical peak, shifting a part or full to the off-peak period could have significant economic effects on both energy supply and demand sides. This shifting technique is accomplished by storing energy during off-peak periods to be utilized during peak periods. The wallboard enhanced with PCM can provide latent heat thermal energy storage (TES) distributed in the whole surface area of the building envelope and evade the enhanced thermal mass in light weight buildings. Identifying the best design parameters of the PCM wallboard is the main key to apply this latent heat TES efficiently. The effective dimensionless numbers on the thermal dynamics of a PCM wallboard were identified. Moreover, the impact of the change of those numbers on the time required for the wallboard to become fully charged was evaluated. This parametric study provided a tool to characterize the required thickness of a PCM wallboard which needs to be charged during the off-peak. The tool presents the Fourier number as a correlation of Biot number and Stefan number. Moreover, the impact of melting range on the charging time of a PCM wallboard was investigated. (C) 2014 Elsevier Ltd. All rights reserved.