System modeling of the thermal behavior of a building equipped with facade-integrated photobioreactors: Validation and comparative analysis

A microalgae-based biofacade is a double-skin facade with integrated photobioreactors (PBRs) for solar cultivation of microalgae. One purpose of cultivating microalgae on building facades is to create an 'active' facade that can reduce the energy consumption required to maintain thermal comfort inside the building, by creating exchange loops between the building and the microalgae cultivation system. This paper describes the experimental validation of a thermal model of a building equipped with a biofacade PBR, and its use in analyzing the energy consumption of international-standard buildings in two different climate conditions (oceanic climate using the weather data from Nantes, France, and semi-arid climate using weather data from Los Angeles, USA). The results of this analysis show that the microalgae biofacade almost entirely removes the building's cooling demand, and the warmer the location the stronger the effect. In addition, the heating demand of the biofacade PBR is also greatly reduced (between 92% and 100% depending on the location). The microalgae biofacade is therefore a more sustainable solution to produce valuable biomass and a promising technology for the development of zero-emission buildings; to this end, suggestions for optimizing the process are put forward.