i2Cool secures nearly HK$100 million in Series A financing, accelerating the commercialisation of its green energy-saving radiative cooling technology
As global warming worsens, scientists around the world are dedicated to researching solutions to reduce emissions and save energy. However, these research findings need to be transformed and commercialised to truly address societal needs. Researchers from the School of Energy and Environment at City University of Hong Kong (CityUHK) developed a low-cost, long-lasting and highly efficient “electricity-free cooling coating” and subsequently established start-up company i2Cool through CityUHK’s HK Tech 300 programme. To date, i2Cool has more than 100 application projects in various regions around the world and reached its Series A funding target of nearly HK$100 million in May 2024 to support its breakthrough solution for indoor cooling and refrigeration and contributing to global efforts to address climate challenges.
i2Cool was incubated under the HK Tech 300 programme, which provided the company with seed funding and angel fund investment. It was also one of the start-ups selected for the Incu-Tech programme of Hong Kong Science and Technology Parks Corporation. i2Cool recently closed its Series A funding, attracting nearly HK$100 million, with investors including Trustar Capital (the private equity investment arm of CITIC Capital Holdings Limited), Future Times Technology Holding Company Limited, The Hong Kong and China Gas Company Limited (Towngas) and investors from previous funding rounds. The capital raised will be used to advance i2Cool’s research and development of new technologies, expand its product portfolio and accelerate its expansion into global markets.
From ants to cooling coatings
i2Cool’s iPaint electricity-free cooling coating is a zero-energy, refrigerant-free passive radiative cooling coating developed by Professor Edwin Tso Chi-Yan, Associate Professor from CityUHK’s School of Energy and Environment, starting in 2016. The project was inspired by the Saharan silver ant, whose unique surface hair structure has mechanisms for sunlight reflection and passive radiative heat dissipation, enabling it to withstand temperatures above 70°C and intense sunlight. i2Cool’s technology has received several international patents.
Passive radiative cooling technology requires no electricity or refrigerants; instead, it achieves cooling through the principles of optics, thermodynamics and materials science. The iPaint coating developed by the team can be applied like paint to building exteriors, roofs and other surfaces. It efficiently reflects ultraviolet, visible light and near-infrared rays, and radiates mid-infrared rays with wavelengths of 8 to 13 micrometres into outer space. It effectively controls the absorption and release of heat from exterior walls, cooling down the interior and providing an electricity-free cooling effect. Both the coating’s solar reflectivity and mid-infrared emissivity reach 95%, which is a leading performance in the industry. It also overcomes the technical bottleneck of traditional insulating coatings, which struggle to achieve more than 90% reflectivity.
Overcoming technical hurdles: delivering low-cost, highly durable coatings
However, transforming laboratory research results into practical applications requires consideration of the challenges posed by real-world environments. “In the past, I pursued numbers like reflectivity, emissivity and cooling performance in the lab,” said Professor Tso. “But when applied outdoors, the coatings became brittle or yellow after just a month, making them impractical for long-term use. If we simply improved its durability, the emissivity couldn't be maintained above 90%, making it not much different from ordinary white paint or insulation materials in the market.”
The original raw materials for the coating were precious metals, which were neither durable nor cost effective. To achieve a breakthrough, the team changed its strategy. Dr Martin Chu, from Professor Tso's research team, was a doctoral student in the School of Energy and Environment at that time and is a co-founder and the CEO of i2Cool. He pointed out that previous research had focused on the scattering ability of a single point or particle of a substance, but the team’s strategy is to study the effects of different particles on optical scattering, thereby improving particle size, shape and arrangement.
“We eventually developed an alternative solution by replacing the original precious metal materials with polymers and nanoparticles commonly used in construction materials. This retains the highly efficient cooling effect while making the coating less prone to cracking, resulting in a lifespan of five to ten years,” said Martin. “In terms of large-scale production, iPaint has a significant price advantage over similar functional materials, helping to accelerate the commercialisation process.”
Currently, the coating developed by the team can reduce building surface temperatures by about 30-42°C and indoor temperatures by about 6-8°C, helping to reduce the use and improve the efficiency of air conditioning, reducing electricity consumption by more than 20–30%.
HK Tech 300 facilitates start-up ideas and helps society reduce carbon emissions
While energy conservation and power reduction certainly help address global climate issues, research technologies also need to be commercialised to enter the market and benefit society at large. CityUHK launched the HK Tech 300 innovation and entrepreneurship programme in 2021, which prompted the team to come up with the idea of commercialising their technology. The team founded i2Cool in June that year and joined the HK Tech 300 programme. They received seed funding of HK$100,000 to develop the technology and buy equipment and raw materials, and then HK$1 million in angel fund investment from the programme to support product development and growth.
Martin acknowledged that the team were novices in business operations and faced many difficulties in the early stages of the company. “Fortunately, we were part of the HK Tech 300 programme, which paired us with entrepreneurial mentors who provided valuable advice on the company’s business model, customer targeting and other areas, helping us set the company’s development direction,” he said. The mentors also provided the team with various suggestions, such as encouraging them to develop coatings in different colours and even applying the technology to clothing and other materials, in addition to considering market demand.
At present, i2Cool’s electricity-free cooling technology is used in its iPaint electricity-free cooling coating and has been developed into iFilm radiative cooling film, which can be applied to the glass curtain walls of buildings. By the end of 2023, the products had been applied in more than 100 projects worldwide, involving industries and facilities, such as construction, power and telecommunications, the chemical industry, logistics, new energy, photovoltaics and grain storage, covering mainland China, Hong Kong, Southeast Asia, the Middle East, Europe, and 20 other countries and regions.
The company has also collaborated with volunteer organisations to apply the coating to the roofs or external walls of schools and subdivided flats to improve the living environment of disadvantaged groups.
Continuous innovation: developing the next generation of cooling products
As its products begin to reach the market, the team’s pursuit of innovative technology has never ceased. The latest cooling tiles developed by Professor Tso’s research team maintain stable cooling performance even in adverse weather conditions. Their research results were published in the internationally renowned journal Science in November last year. In addition, i2Cool was awarded the “Gold Medal with the Congratulations of Jury” at the International Exhibition of Inventions of Geneva in 2021 and was selected as one of Forbes Asia’s “100 to Watch" in 2022.
In the future, i2Cool will expand its product line into various fields, such as ceramics, textiles and automotive paints, and will continue to actively research and develop new-generation coating products, including thermochromic smart windows, biodegradable dual-mode thermal management textiles, and applications of passive radiative cooling road surface materials, thus contributing to global carbon emissions reduction and sustainable development.
