Energy prices around the world have skyrocketed since 2021, and many of us are now feeling the pinch. While some share advice on how to heat people rather than their homes, KTH researchers are working on building materials that help regulate indoor temperatures.
The new composite is the work of a research team at the Department of Biocomposites at KTH Royal Institute of Technology in Stockholm, Sweden, and utilizes three renewable sources of materials: coconut, lemon and wood.
Researchers first created an open pore structure in wood by removing lignin. This will also strip the color. We then filled in the gaps with limonene acrylate (obtained from pericarp waste from the juice industry) and a coconut-based molecule.
When the composite heats up from exposure to sunlight or elevated ambient temperatures, the limonene acrylate becomes a polymer, trapping the coconut molecules inside. The temperature at which the transition occurs can be adjusted to suit your requirements, but for this project it was set to a comfortable 24 °C (75 °F). And as the material cools, this process is reversed.
“The idea is that the coconut molecules can transition from a solid to a liquid that absorbs energy, or from a liquid to a solid that releases energy,” said KTH researcher Celine Montanari. “This transition allows us to heat or cool our surroundings as needed,” added team member Peter Olsen.
It is not yet ready for construction use, but the first use of the ‘wood composite thermal cell’ is as an internal partition wall or, as the material has some transparency, it can be used as a screen of sorts. There is a possibility. However, the team says more work is needed before it is ready for use as an exterior building material.
It is estimated that for every 100 kg (220 lbs) of material used in building construction, a savings of about 2.5 kWh per day is possible (assuming an ambient temperature of 24 °C). However, it may also be used in the garden.
“How do you see it as a material of the future for greenhouses?” asked Olsén. “When the sun shines, wood becomes transparent and stores more energy. It gives off heat. This allows us to reduce energy consumption for heating and at the same time improve growth.”
A study was published in a journal small.
Source: KTH
