Advancing building energy simulations: Integrating photobioreactor façades for enhanced energy efficiency and comfort

Abstract

Photobioreactors (PBRs) offer to reduce energy consumption, enhance thermal and visual comfort, capture carbon, and generate energy in buildings. Despite their potential, PBRs remain under development and face theoretical and practical challenges. Theoretical issues include the inherent characteristics of PBR elements, complicating their simulation by building professionals. Practical challenges involve the continuous maintenance required for their operation. This study aims to advance the understanding of PBRs as building elements that can be evaluated using common simulation tools. Particularly flat plate PBRs, which comprise two transparent sheets containing a liquid medium for growing microalgae. By treating these PBRs as windows in energy and lighting simulations, this research seeks to make them accessible to building professionals. The novel contribution of this study lies in the fact that the changes in viscosity and thermal conductivity during the growth of microalgae in liquid media have not been analysed in literature. Alongside light transmittance, these values can characterize windows for use in building energy simulation tools. Through parametric analysis and multi-objective optimization, this study demonstrates the renovation potential of a building with three alternative PBR façade configurations. The results show that PBR façades can significantly control daylight transmission and affect building energy loads. All optimal solutions of Façade Proposal 2 show improvements on daylighting and energy use while other façades have mixed effects, up to 12 % for daylight and 37 % for energy. Meanwhile, all Façade Proposals improved thermal comfort, with 1, 2, and 3 showing improvements of 37–91 %, 0–99 %, and 62–87 %, respectively.