For people living in areas with little power, or families too poor to afford fuel, cold nights can be both common and uncomfortable. Researchers at Sri Venkateswara College of Engineering and Technology in Chittoor India have devised a novel way to heat these homes after dark. The method takes advantage of materials changing phase, as materials melt when they absorb energy and solidify when they release it.
Using a mixture of paraffin wax and stearic acid, the researchers created beads which will melt under the sun and freeze at night. This material should be able to help homes stay warm without requiring the burning of wood or fossil fuels. Altering the proportions of the wax and acid can keep costs down in India where the wax is much more expensive than the acid.