A new type of material, which can absorb heat from the sun during the day and radiate energy to space to harvest cold at night, has been developed, according to a recently published paper.
The basis of the coating material is a film of vanadium dioxide (VO2). It can switch from heating mode to cooling mode throughout a 24-hour day-night cycle and incurs no additional energy cost in this process, according to Pei Gang and Zou Chongwen, lead scientists of the study conducted by the University of Science and Technology of China.
Due to its self-adapting properties, the VO2 film is in a metallic phase and can be heated to 170 degrees Celsius above room temperature under the sun, while in the dark the VO2 film turns into an insulator and can be cooled to 20 degrees Celsius below ambient temperature.
The study represents a novel approach to harvesting renewable energy from sunlight and space and is of emerging interest, according to its peer review.
The study’s breakthrough is to harvest “heat and cold” in a single structure, which saves space and reduces costs, Pei said.
The material might be applied to areas such as energy conservation in buildings, cooling in photovoltaic systems, thermoelectricity and space energy supply, according to Pei.
The high cost is currently a problem for the use of this material. However, substitute materials using similar but less efficient techniques are on the way to mass production, Pei added.
The results have been published online in the journal “Proceedings of the National Academy of Sciences.”
