Mitsubishi Electric Corporation and Professor Akiyoshi Hayakawa of Tokyo University of Science have developed the world's first heat storage material that uses a water-based thermosensitive polymer gel to store low-temperature heat (30°C to 60°C) at the world's highest heat storage density. This will promote the recovery and reuse of discarded low-temperature waste heat, and contribute to the realization of a carbon-neutral society.
As part of the drive to conserve energy, there is a demand for inexpensive heat storage materials that can store low-temperature waste heat (especially below 80°C) at high density (333 kJ/L or more) to effectively utilize waste heat. However, since the lower the heat storage temperature, the lower the heat storage density generally becomes, little has been developed.
High concentrations of polymers exist in the cytoplasm of living organisms, including humans, forming a "polymer-crowded environment." On the other hand, the lower the order of water molecules, the higher their energy. Using Mitsubishi Electric's molecular simulation technology, the research group has now succeeded in designing and developing a thermosensitive polymer gel, whose main component is safe and inexpensive water, in which the shape of the polymer changes depending on the temperature and which forms a polymer-crowded environment when heated, and has demonstrated for the first time in the world that it is possible to store heat at high density even at low temperatures.
When the thermosensitive polymer gel was synthesized and evaluated at the laboratory level, it was found to have the world's highest heat storage density (60 kJ/L), more than double that of conventional commercially available products, at a low heat storage temperature of below 2°C. In addition, the synthesis reaction control technology developed by Tokyo University of Science made it possible to homogenize the thermosensitive polymer gel, and a heat storage density equivalent to that at the laboratory level was confirmed in mass synthesis trials.
The developed heat storage material is effective in recovering and reusing low-temperature exhaust heat that has previously been dumped into the atmosphere from factories, automobiles, offices, residential environments, etc., and is said to reduce fossil fuel consumption and contribute to the realization of a carbon-neutral society through energy conservation and decarbonization.
