A Huge and Unexpected Use for Coffee: Scientists Discover Using Coffee Grounds for Thermal Insulation

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A Huge and Unexpected Use for Coffee: Scientists Discover It

Scientists in South Korea have discovered a new and unexpected use for coffee grounds, representing a significant advancement in its applications and potentially leading to its use in entirely new and unconventional fields.

According to a report published by Science Alert, a website specializing in scientific discoveries, South Korean scientists have successfully used coffee grounds for thermal insulation.

A team from Jeonbuk National University (JBNU) transformed coffee grounds into an effective insulating material, comparable to those currently used in buildings. The advantage lies in the fact that this new material is made from renewable resources and is biodegradable upon disposal.

“Coffee grounds are produced in enormous quantities worldwide, yet most of them end up in landfills or are burned,” says Seung-Yoon Kim, a materials engineer at Jeonbuk National University. Research shows that this vast amount of waste can be recycled and transformed into a high-value material that performs as well as commercial insulation products, while being far more sustainable.

Using coffee grounds for "thermal insulation

The world collectively consumes about 2.25 billion cups of coffee every day, which translates into enormous amounts of wasted grounds. Most of these grounds are burned or buried, causing environmental damage comparable to flushing them down the sewer system.

Instead, scientists are increasingly discovering more beneficial uses for coffee grounds. The recent study explored their potential use in concrete and other paving materials, removing herbicides from the environment, and even extracting new pharmaceutical compounds from them.

In the new study, the Jeonbuk National University team investigated the effectiveness of coffee grounds as a thermal insulating material. First, the coffee grounds were dried in an oven at 80°C (176°F) for a week, then cooked at much higher temperatures to produce a carbon-rich material known as biochar.

This biochar was then treated with environmentally friendly solvents—water, ethanol, and propylene glycol—and mixed with a natural polymer called ethyl cellulose. Finally, the powdered mixture was pressed and heated to form a composite material.

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The polymer stabilizes the biochar, while the solvents are added to prevent the polymer from clogging the material's pores. These pores are an important property because they trap air, which is a very effective insulator. 

The thermal conductivity of a material is measured in watts per meter per kelvin (W/mK), which is the amount of heat energy (in watts) that passes through a material of a given thickness (in meters) when there is a temperature difference (in kelvin) between its two sides.

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Materials with a thermal conductivity of less than 0.07 W/mK are generally considered insulators. The most efficient thermal conductivity of the coffee-based composite material was found to be only 0.04 watts per meter per kelvin.

In laboratory tests, researchers placed a variety of insulating materials, including the coffee-based material, beneath a solar cell and measured the air temperature in a small chamber under the cell. This miniature model, designed for use on a lab bench, simulates how insulation prevents excess heat radiated from solar panels from penetrating and heating rooftops.

The version treated with the new material maintained a consistently lower temperature than the untreated version, and its performance was comparable to that of expanded polystyrene, one of the best commercially available insulating materials.