(449e) Combined Thermochemical and Latent Heat Energy Storage for Low Temperature Residential Applications

Solar thermal energy has the potential to supply clean energy, but for space heating and cooking applications, peak usage times often are misaligned with peak solar hours. Solar thermochemical energy storage systems are one promising solution. Salt-hydrate reactions are well-suited to this purpose as they have low-decomposition temperatures and high energy densities. To enhance heat transfer, improve durability, and prevent conglomeration, a solid matrix material is used, typically made of porous substances such as activated carbon, vermiculite, or expanded graphite. Here, a matrix of expanded graphite reinforced with carbonized flour was used. Certain salt-hydrates have the potential to store both thermochemical and latent heat, and one such salt was investigated through TGA/DSC analysis. A functional eutectic was found at around 130°C and freezing/melting cycles were visible as well-defined peaks. The salt-matrix complex was also investigated through both TGA/DSC and realistic application testing. The success of this new chemistry sets the stage for a new dual-release approach to energy storage.