A team of researchers from the Massachusetts Institute of Technology (MIT) found a way to store solar heat during the day and release it when needed. MIT professor Jeffrey Grossman, postdoc David Zhitomirsky and graduate student Eugene Cho worked in the configuration of the molecules so that they can lock in solar energy or solar heat for a longer period of time. The configuration triggers a chemical change on the molecules allowing them to store heat then release this energy by exposing it to a stimulus or specific temperature. Once the solar heat is released, it goes back to its original form.

The technology is dubbed as "solar thermal fuels" (STF). STF is already used on liquid materials, but this MIT study published in the journal Advanced Energy Materials is the first to apply it on solid materials. If successfully developed, it can be used on surfaces such as window glass or clothing.

"Manufacturing the new material requires just a two-step process that is very simple and very scalable," Cho said in a university news release. "The system is based on previous work that was aimed at developing a solar cooker that could store solar heat for cooking after sundown, but there were challenges with that. The team realized that if the heat-storing material could be made in the form of a thin film, then it could be incorporated into many different materials.

"The approach is innovative and distinctive," commented Ted Sargent, university professor at the University of Toronto, in the news release. "The research is a major advance towards the practical application of solid-state energy-storage/heat-release materials from both a scientific and engineering point of view."

STF is a cost-effective energy source proven by an earlier study that recycled the solar heat for more than 2,000 cycles with no loss in performance, ArsTechnica reported.

However, don't expect batteries to be developed by MIT, not anytime soon. It turns out that BMW is one of the supporters of the new research and the MIT team is currently working on improving its film materials, especially its transparency. With this in the works, it seems that we have an idea now of the future of car windshields.