MIT researchers have developed a new transparent polymer film that can store solar energy during the day and release it later as heat, whenever needed. The material could be applied to many different surfaces, such as window glass or clothing.
The new material solves a problem with renewable solar energy: the Sun is not available at night or on stormy days. Most solutions have focused on storing and recovering solar energy as electricity or other forms.
Ref: Solid-State Solar Thermal Fuels for Heat Release Applications. Advanced Energy Materials (8 January 2016) | DOI: 10.1002/aenm.201502006
Closed cycle systems offer an opportunity for solar energy harvesting and storage all within the same material. Photon energy is stored within the chemical conformations of molecules and is retrieved by a triggered release in the form of heat. Until now, such solar thermal fuels (STFs) have been largely unavailable in the solid-state, which would enable them to be utilized for a multitude of applications. A polymer STF storage platform is synthesized employing STFs in the solid-state. This approach enables uniform films capable of appreciable heat storage of up to 30 Wh kg−1 and that can withstand temperature of up to 180 °C. For the first time a macroscopic energy release is demonstrated using spatial infrared heat maps with up to a 10 °C temperature change. These findings pave the way for developing highly efficient and high energy density STFs for applications in the solid-state.