Yorkshire father and son invent 'revolutionary' cooling paint in home garage during lockdown

A rigorous validation process subsequently took place with the University of Leeds, with more than 800 samples tested over a two-year period.

Field tests in India and the UK showed a maximum drop in temperature of up to 7C compared to standard cooling paints already on the market.

The results are due to be published in a scientific journal once they have been reviewed.

The family inventors have now launched Harrogate-based company Pirta and are working with US-based venture accelerator firm Apater Labs to make the most of the “immense” commercial potential of the product.

They are targeting billion-dollar market segments including construction, logistics, agriculture and shipping on the basis that use of the paint could reduce reliance on energy-intensive cooling systems – helping to cut both costs and emissions.

Howard Atkin, sustainability director for Pirta, said lockdown was a key inspiration for their work.

“As everything ground to a halt, I think we all felt the fragility of human existence. It was a sobering moment, compounded by a growing sense of doom around the current climate crisis. Necessity is often the mother of invention, and with this backdrop we felt compelled to develop a solution specifically geared towards protecting our planet and creating a better future for our children and grandchildren.

“One of our key areas of expertise is insulation, so we started looking at coating systems which could passively cool surfaces. There are plenty of solar reflective paints on the market which reflect light, but few are effective at repelling heat. Despite this, we see lots of examples of passive cooling in nature, so we knew it was possible. The example that we liked was the silkworm. It chooses a leaf from which it will hang by a silk thread, and it then weaves its cocoon. If it happens to be in a place where there’s a lot of sunshine, the structure of the cocoon keeps it cool. We’ve since looked to incorporate elements of biomimicry in our coating systems in order to enhance their passive cooling qualities.”

Pirta R&D Director Robert Atkin added: “To get the project off the ground we sent the University all kinds of materials from Teflon tape to white cooking glass, and even cat litter which is made of calcium carbonate and widely used in solar reflective paint. Using highly sophisticated equipment they were able to characterise these different materials which allowed us to start formulating our system.

"Eventually we made our first breakthrough when we discovered a variety of materials with a high reflective index and strong density. Each one of our tests spawned another approach, and it grew like ripples on water. We’re now embarking on ‘ladder tests’, which are standard in the paint manufacturing industry, applying different doses of raw materials to assess performance.

"We are also focussing on tackling complexities involved with paint production at commercial scale, and the practical application including compatibility with spraying equipment.”

Pirta CEO Scott Fleming said: “The potential of passive cooling technology is now firmly on the world’s radar. There is a major requirement across industries and continents to offset rising temperatures. With another year of record-breaking temperatures being forecasted in the UK by the Met Office, Pirta is arriving with a simple yet highly effective solution to tackle heat management, in turn helping reduce energy consumption and emissions.”