Solar cells and nanotechnology to cut global energy use

Microscopic nanoparticles in building materials are being tested in Norway to reduce heat transfer, as well as solar cells that prevent heavy roof-top snow accumulations to cut climate gas emissions.  

A team of researchers at SINTEF are revamping construction materials by using high-tech systems integrated into building shells to consume less energy and generate less harmful emissions. They are currently testing microscopic nanoparticles as insulation materials, applying voltages to windows and facades to save energy, and creating in-the-roof solar cells to help people get rid of snow loads.

Even though cars and general traffic account for a considerable part of the climate gas emissions, the building sector is responsible for nearly 40 per cent of the global energy use, the engineers said, often an under-communicated problem.

Researcher Bente Gilbu Tilset of SINTEF has been testing super-insulation materials made of microscopic nanospheres. “Our aim is to create a low thermal conductivity constriction material,” she said.

“When gas molecules collide, energy is transferred between them. If the pores in a given material are small enough, for example less than 100 nanometres in diameter, a molecule will collide more often with the pore walls than with other gas molecules. This will effectively reduce the thermal conductivity of the gas, so, the smaller the pores, the lower the conductivity of the gas.”

The team hopes to aggregate the nanospheres – currently only available as powder – to form flexible mats and reduce existing insulation material’s thickness to lower the inward-outward transfer of energy and calibrate temperature.

When it comes to solar cells, the researchers are looking to integrate them into the roof tiles and external walls rather than traditionally fixing them to panels, and see them as integral building construction components.

However, developing the solar cells that can fight off the accumulation of snow and ice is not an easy task. The cells must be robust enough to withstand harsh wind and weather conditions and have lifetimes that enable them to function as electricity generators.  

“We will also be developing the construction materials so as to optimise their ability to adapt to Norwegian daylight conditions where the sun is low in the sky and solar radiation commonly diffuse”, said researcher Tore Kolås.

The technologies are part of the so-called ‘phase-changing’ materials that can both absorb and release energy. Using different pigments – thermochromic, photochromic and electrochromic – can help control how the sun enters buildings for example or release temperature into the room – some are already on the market.

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