Photothermal heating applications in buildings: Development, challenges and optimization

Photothermal heating, which enhances solar radiation absorption and converts it into thermal energy using photothermal nanomaterials, offers significant potential for addressing energy sustainability challenges. Considering the building sector responsible for over one-third of global energy consumption and carbon emissions, this review comprehensively explores the incorporation of photothermal technology into building systems and proposes optimization frameworks to promote energy-efficient, low-carbon buildings. With foundational insights into photothermal material properties and energy conversion mechanisms, the study evaluates the sustainable heating performance and energy-saving potential of photothermal applications across building envelope components, including windows, roofs and walls. An examination of numerous case studies of photothermal building envelopes reveals six major challenges to widespread adoption: limitations in heating capacity, uneven contributions from specific envelope elements, seasonal compatibility constraints, compromised indoor thermal performance, durability degradation, and dependence on geography and climate zones. To overcome these challenges, dual optimization strategies are proposed, including the enhancement of material-level photothermal properties through nanoparticle morphology modulation and the integration of supplementary heating methods at the building scale to refine indoor thermal management. This review compiles the various advances, challenges, and scalable solutions for deploying photothermal technology in the building envelopes, providing an optional roadmap for the development of sustainable buildings.