SWEDEN

Cooling With Coconuts

Researchers in Stockholm, Sweden have used coconuts, lemons, and modified wood to create a “wood composite thermal battery”.

According to the research study, when used in housing construction, the material can capture both heat and cold. Given an ambient temperature of 24°C, the team estimated that 100kg of the material could save about 2.5kWh per day in heating or cooling.

The process begins with removing lignin from wood, which opens pores in the material and makes the wood transparent. The gaps are then filled with citrus (limonene acrylate) and coconut based molecules.

When heated, limonene acrylate molecules transform into a bio based polymer, restoring the wood’s strength and allowing light to permeate. As a result, the coconut molecules can become trapped inside the material, facilitating energy storage and release.

Study author Céline Montanari says that the coconut molecules can transition from a solid to liquid, which absorbs energy; or from liquid to solid, which releases energy, in much the same way that water freezes and melts. This transition method can heat or cool the immediate surroundings as needed. ■