Active solar design principles for natural and architectural heritage

In response to the global energy crisis and environmental concerns, international regulations emphasize the widespread adoption of solar renewable energy in the built environment, aiming to curtail energy consumption, emissions, and costs. However, these policies could generate serious challenges for conserving heritage buildings, protected areas, and landscapes of historical importance. The integration of active solar systems into cultural heritage sites emerges as a delicate endeavor for seeking a balance between sustainable architecture and energy efficiency. This study conducts a comprehensive examination of international guidelines for energy efficiency and solar integration within heritage contexts. The assessment focuses on integration criteria and practices for photovoltaic and solar thermal systems. Esthetic, technical, and energy design principles have been proposed for integrating active solar technologies in natural and architectural heritage. For each level of integration, recommendations, positive elements, and critical aspects are meticulously explored, considering heritage conservation and energy generation. The evolution of solar cell technology is presented, discussing heritage compatibility, reversibility, and energy production of both conventional and innovative materials. Conventional panels encounter limitations within protected areas and historic buildings due to their blue/dark color, high reflectance, standard dimensions, framing, and thickness. Conversely, innovative solar cells offer a more harmonious integration by customizing shapes, sizes, reflectance, colors, and textures to be aligned with heritage esthetics.