Introduction to Molecular Solar Thermal Systems

Paper in proceeding, 2025

Thermal energy management-both heating and cooling-is essential across all scales of modern society, from industrial processes and residential systems to nanoscale electronics. These applications account for approximately 50% of the EU's total energy consumption. Conventional heating and cooling methods rely heavily on fossil fuels, contributing significantly to global emissions and environmental degradation. An emerging alternative involves the use of molecular photoswitches for solar energy capture and storage. These compounds can absorb sunlight and store energy as high-energy isomers, releasing it later as heat on demand. This concept, termed Molecular Solar Thermal (MOST) energy storage, offers a promising route to clean, local thermal energy generation. This book explores both fundamentals and applications of MOST systems, including their molecular design, photochemical efficiency, energy storage density, and stability. It also discusses recent advancements in MOST-device integration, hybrid systems, and the combination with phase change materials (MOST-PCM) to enhance energy density and functionality. Despite challenges in efficiency and scalability, MOST technologies have made remarkable progress, with some systems approaching the efficiency of natural photosynthesis and beyond. The book provides an overview of state-of-the-art research and highlights the potential of MOST systems in addressing future energy and environmental challenges.