Numerical study of slim curtain wall spandrel with integrated vacuum insulation panel: Concept, performance evaluation and challenges

The thermal and energy performance of curtain wall facades can be improved by incorporating spandrel units in areas such as slabs/plenums to hide existing building services or areas where concealment of indoor space is required. The main objective of this study was to numerically investigate the performance of curtain wall facade with integrated vacuum insulation panel (VIP) as spandrel insulation. The main study constitutes six parts: (1) concept and derivation of governing equations, (2) model and its validation, (3) VIP integration alternatives, (4) overall thermal performance considering 2D/3D thermal bridges and internal surface temperatures, (5) building energy and vision-spandrel ratio effect, and (6) limitations and challenges. Thermal behavior of the system was characterized via 3D heat transfer simulations using Physibel TRISCO according to EN ISO 10211, while dynamic building energy analysis was carried out using EnergyPlus based on a stereotypical office building unit, in relation to the humid continental climate of Incheon, Republic of Korea, The baseline model was validated with experimental data from previous study, and a marginal discrepancy less than 4% was found between them. Further, the validated model was developed into different spandrel configurations, seeking to mitigate thermal bridges while improving insulation performance, by varying VIP integration design. Results indicated that the best VIP spandrel alternative improved thermal performance of the system by about 30%. Moreover, year-round space heating and cooling energy reductions were realized by gradually increasing the spandrel area by ratio from 0% to 80%, howbeit at the expense of electrical lighting energy. Finally, some noteworthy limitations of the study and challenges related to VIP integration into curtain wall spandrel have been duly discussed. (C) 2018 Elsevier B.V. All rights reserved.