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A new way to store thermal energy

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In large parts of the developing world, people have abundant heat from the sun during the day, but most cooking takes place later in the evening when the sun is down, using fuel — such as wood, brush or dung — that is collected with significant time and effort.

In large parts of the developing world, people have abundant heat from the sun during the day, but most cooking takes place later in the evening when the sun is down, using fuel — such as wood, brush or dung — that is collected with significant time and effort.

Now, a new chemical composite developed by researchers at MIT could provide an alternative. It could be used to store heat from the sun or any other source during the day in a kind of thermal battery, and it could release the heat when needed, for example for cooking or heating after dark.

A common approach to thermal storage is to use what is known as a phase change material (PCM), where input heat melts the material and its phase change — from solid to liquid — stores energy. When the PCM is cooled back down below its melting point, it turns back into a solid, at which point the stored energy is released as heat. There are many examples of these materials, including waxes or fatty acids used for low-temperature applications, and molten salts used at high temperatures. But all current PCMs require a great deal of insulation, and they pass through that phase change temperature uncontrollably, losing their stored heat relatively rapidly.

Continue reading at Massachusetts Institute of Technology (MIT)

Photo: MIT postdoc, Grace Han, handles a new chemical composite that could provide an alternative to fuel by functioning as a kind of thermal battery.

Photo Credit: Melanie Gonick / MIT