Father and son develop a paint formula to address global warming

Engineering dynamos Howard and Robert Atkin began working on the paint formula during the Covid-19 lockdown before launching a rigorous validation process with the University of Leeds, testing more than 800 samples over a two-year period.

The results reveal exceptionally high emissivity, or ability to release heat, with the provisional results reaching 0.998 on a scale of 0-1. Due to its unique properties, the paint formula can reduce surface temperature by up to 64°C (114.4°F) compared to a black surface as revealed by its Solar Reflective Index (SRI). 

The paint formula’s SRI, recognised in the USA as an industry standard for measuring material thermal properties, was valued at 116.8. While most materials have an SRI between 1 and 100, higher values indicate greater reflectance and emissivity and an improved ability to passively cool a structure. The field tests in India and the UK showed a maximum drop in temperature of up to 7°C compared to a standard cooling paint available in the market.

Lab tests showed a peak reflectance of 99.82% across visible and ultraviolet light spectrums. The overall performance was calculated using both reflectivity and emissivity scores, returning a Figure of Merit of 0.934.

Once reviewed, these results will be published in a scientific journal.  

With immense commercial potential as a passive cooling agent, the family inventors have now recruited US-based Venture Accelerator firm Apater Labs to help package their paint formulas under newly launched enterprise Pirta Ltd, headquartered in Harrogate, UK.

Together, they will target billion-dollar market segments including construction, shipping, logistics, agriculture, and energy industries, which all share common aims to reduce over-reliance on energy-dependent cooling systems while mitigating a current climate crisis.

Serial product designer and Pirta Sustainability Director Howard Atkin said the chaos of Covid-19 provided the spark of inspiration for their paint product. “The lockdown enforced during the global pandemic was a bizarre and bewildering experience,” he said. “However, it also created a kind of ‘global’ pause for thought. 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.”

The father and son initially worked with the University of Leeds in 2017 on a fibre optic power transmission project where they met Professor Gin Jose, resident expert in Functional Materials. They reconnected to pitch the paint cooling idea before securing grant funding to underpin the project. Laboratory testing was performed at the University of Leeds by Experimental Officer Dr Eric Kumi Barimah between March 2021 and September 2022. Field tests of paint formulations were carried out in the UK, and in India in collaboration with Professor P R Biju at the School of Pure and Applied Physics, Mahatma Gandhi University, Kerala.

Pirta R&D Director Robert Atkin said: “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: “We are enormously grateful to the University of Leeds for their dedication to this project, and in particular to Professor Gin Jose and Dr Eric Kumi Barimah. It simply wouldn’t have been possible to progress at this pace without their guidance and expertise, combined with the University’s world class testing facilities. We look forward to continuing this partnership work and broader mission to cool our warming planet through scientific innovation. 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.”

Pirta has received support from UK Government backed authorities, investment arms and innovation accelerators including Leeds City Region Local Enterprise Partnership, Innovate UK Edge, and the Centre for Process Innovation (CPI).