Environmental Benefits of Repurposing Smartphones in Building Automation

While intelligent energy systems can enhance the energy efficiency of buildings, the production and transportation of related digital equipment, such as sensors and control units, can offset the efficiency benefits by increasing resource consumption and environmental impacts from the installation. This study investigates the potential environmental benefits of using discarded smartphones instead of traditional programmable logic controllers (PLCs) to evaluate if equipment for building automation can become more sustainable. A life cycle assessment of both technologies is conducted using the ecoinvent v3.10 cut-off database, the OpenLCA software, and the ReCiPe 2016 midpoint (H) method. Results show that repurposed smartphones significantly reduce the environmental impacts of control units compared to PLCs, with notable reductions in toxicological stress on human health and freshwater eutrophication. Findings about the electricity consumption of manufacturing steps, i.e. the primary contributor to environmental impacts, make this study of the environmental benefits from cross-sector reuse strategies relevant beyond their uses in buildings.