Optimization of an adaptive algae façade based on solar radiation simulation

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Due to the climate crisis, extreme fluctuations in temperature are caused by the high sources of energy, and carbon consumption have a great impact on both construction and water resources management. Accordingly, the world today is paying attention to searching for cleaner energy resources. In Egypt, the extreme heat of the summer seasons causes constant air-conditioner (AC) usage in building to provide cooling, which produces outlet wastewater. The continuous flow of this outlet wastewater results in cracks and erosion among the facades that need maintenance. As a way to search for environmentally friendly material that can reuse this outlet water and reduce the solar radiation on the façade providing more cooler spaces, algae are suggested due to their availability in water from several sources in Egypt. This paper presents the assessment of an innovative façade element photobioreactors (PBR) made from algae on a real administrative building facade in Cairo. The aim is to evaluate digitally by simulation the solar radiation reduced from the façade that acts as a double green skin and self-watering system with an appealing aesthetic form preventing any erosion on the façade surfaces. The method of assessment is done using Ladybug plug-in simulation in Grasshopper plug-in in Rhino software based on the climatic data from EnergyPlus. Four main phases are followed: 1) the form generation of the façade using Rhinoceros software, 2) the simulation to assess the solar radiation before and after adding the PBR, 3) the evaluation phase to calculate the thermal conductivity and water temperature mathematically, and 4) fabrication of small-scale façade using the 3D-printed technique with algae filament. The results recorded a reduction in the solar radiation from 301 to 75 kWh/m2 comparing the current case of the building façade, while the thermal performance was 0.36 W/m2K, which is better than the most common materials used in arid climates such as rammed earth, fired brick, and concrete. The optimization of the algae tube length was based on the required outlet temperature that is suitable for plantation 15°C to help in reducing the water temperature. The finding addresses the significant role of using algae that can generate biomass to explore their benefits regarding their O2 production and CO2 absorption through 3D printing, which is considered a cleaner technology.