Document Type

Theses, Ph.D

Disciplines

Civil engineering

Abstract

Buildings account for a significant share of global energy use, and improving façade performance is critical to achieving nearly zero-energy building targets. This research addresses the challenge of integrating multiple adaptive functions into a single façade system to reduce heat loss, harness solar energy, and provide dynamic environmental control. The aim was to design, construct, and evaluate an adaptive Multi-Functional Façade (MFF) that integrates vacuum glazing, switchable opacity glazing, and a ventilated cavity with active airflow control to provide façade insulation, heated fresh air, recirculated air, or exhaust ventilation.

A Solar Thermal Test Cell (STTC) designed to Passive House standard, with an overall area weighted U-Value of 0.19 W m2𝐾 ⁄ was used for full-scale experimental testing under real weather conditions. Temperature, airflow, and solar radiation intensity were measured at 5-to 15-minute intervals and analysed with customised computer code. The Hottel-Whillier-Bliss (HWB) equation was extended and simplified to include heat losses from the front and rear of the MFF, and performance indicators such as thermal efficiency, Solar Heating Fraction (SHF), and Solar Load Ratio (SLR) were analysed.

The MFF was operated in fresh air heating, recirculated air heating, ventilation and insulation with switchable glazing in both transparent and opaque modes. Experimental results show mean thermal efficiencies of between 48 % ≤ 𝜂 ≤ 51 % in both fresh air heating modes, with corresponding mean monthly heat outputs of 45W m2 ⁄ ≤𝑄𝑜𝑢𝑡 ≤60W m2 ⁄ . While the absolute heat outputs were modest due to the available solar resource during the observation period, the SHF values frequently exceeded unity providing surplus thermal energy indicating potential for thermal energy storage. The findings confirm that adaptive glazing combined with controlled ventilation can significantly reduce energy demand while maintaining flexibility in operation. This work provides a foundation for standardised performance rating of adaptive façades and highlights opportunities for further optimisation through advanced control strategies and simulation-based design.

DOI

https://doi.org/10.21427/ywpv-9089

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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