Cooling paint passes toughest tests

Pirta – the name of the company and the paint – has been tested on a solar simulator and shown to be able to reduce surface temperature significantly.

For the past two years, Pirta engineers have been developing a paint that passively cools a structure so that it is less reliant on energy dependent cooling systems. Pirta paint reflects solar heat away from a surface and allows that surface to lose more heat than it absorbs from the sun.

Air pockets in the paint create a lustre, similar to snow or salt, that are colourless but appear white because they reflect light back to the eye. Exploiting reflection and refraction, the irregular structure of Pirta paint not only reflects light and heat away from a surface but also allows heat to move through it and away from the interior of a structure.

It has now been tested to the extreme at TS Space Systems' purpose built site in Marlow, with the results validated by the University of Leeds. Provisional results indicating exceptionally high emissivity, or ability to release heat, reducing surface temperature by up to 64°C.

The technology is reckoned to have commercial potential as a passive cooling agent across a range of industrial sectors, including construction, shipping, logistics, agriculture and energy industries, reducing emissions from energy-dependent cooling systems.

Pirta research & development director Robert Atkin, who set up the company with his father Howard in 2021, said that the initial performance tests paved the way for open-air testing overseas. “This was a fascinating way to begin our testing journey,” he said. “Solar simulators are able to replicate intense UV rays experienced in the troposphere extending 11km above sea level. For our tests, we tuned-up the simulator to deliver a variety of light intensities experienced at terrestrial sea-level where our product will initially be applied. It proved to be a vital learning curve and influenced our next stage of field tests in the UK and in India, delivered in collaboration with Leeds University and the Mahatma Gandhi University in Kerala.”

Pirta’s lab tests have demonstrated a peak reflectance of 99.82% across visible and ultraviolet light spectrums.

Backers of Pirta include Leeds City Region Local Enterprise Partnership, Innovate UK Edge and the Centre for Process Innovation (CPI).

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