Exploring Devices for Molecular Solar Thermal Energy Storage Systems

Licentiate thesis, 2018

The sun is considered to be one of the most abundant and renewable sources of energy. During recent last decades, technologies for solar energy capture and storage have been significantly investigated. An attractive way to store solar light, is to use photochromic molecules that can capture and store solar energy in chemical bonds. When energy is required, it can be released “on demand”, so called Molecular Solar Thermal Energy Storage (MOST). In this thesis, the method and technique for MOST characterization is discussed. Two MOST candidates based on the Dihydroazulene/Vinylheptafulvene (DHA/VHF) and Norbornadiene/Quadricyclane (NBD/QC) have been then characterized. The DHA/VHF system has been evaluated in both indoor and outdoor devices. Moreover, potential catalysts for conversion of the NBD/QC MOST candidate have been identified by testing 15 different metal complexes and salts. Selected candidate was physisorbed on to the surface of activated carbon for a macroscopic heat release demonstration. A record high absolute temperature of up to 83.2 °C was finally observed, thus showing a proof-of-principle from solar energy capture, storage to energy release of the MOST concept in functional devices.