The transformative power of electricity-free cooling

As global temperatures continue to soar – 2024 having been confirmed by the World Meteorological Organization as the hottest year on record, marking 13 consecutive months of historic heat – sustainable cooling solutions have never been more critical. The Middle East, a climate change hotspot, is heating nearly twice as fast as the global average. Without immediate climate action, temperatures in the region could rise by 5 degrees C or more by the century’s end.

The need of the hour is an innovative technology that delivers efficient, electricity-free cooling – ideal for buildings, transportation and various industrial applications.

The science behind electricity-free cooling

The inspiration for electricity-free cooling technology stems from the Sahara Silver Ant, whose unique hair structure reflects over 95% of solar radiation while emitting mid-infrared radiation into outer space. This remarkable adaptation enables the ant to survive in extreme heat.

At i2Cool, our research team – originating from the School of Energy and Environment at the City University of Hong Kong and led by my PhD advisor, Ir Prof. Edwin TSO – posed a bold question: Could the natural phenomenon observed in the Sahara Silver Ant be applied to buildings for passive cooling and energy savings?

Our in-depth study of the ant’s surface revealed insights into its highly reflective properties and passive radiative cooling mechanism. The research culminated in the development of an electricity-free cooling nanomaterial that achieves over 95% solar reflectivity and mid-infrared emissivity, setting a new industry benchmark.

The breakthrough in passive radiative cooling technology was only possible through meticulous material optimisation. Early research primarily focused on key performance indicators such as reflectivity, emissivity and cooling power. However, traditional coating tended to soften and yellow when exposed to outdoor conditions. Additionally, prototypes using precious metals proved too expensive for large-scale application.

To address these challenges, our team shifted its approach, focusing on the selective tuning of the material’s spectral properties. This led to a key innovation: Replacing precious metals with high-molecular polymers and nanoparticles. The result was a material that not only maintained excellent cooling performance but also offered greater durability and significantly lower production costs, achieving an optimal balance among cost, performance and longevity.

Today, by precisely formulating and structuring these materials at the physical level, electricity-free cooling technology has been successfully applied across multiple sectors. For example, passive radiative cooling ceramics can effectively mitigate urban waterlogging and support the development of sponge cities. Other applications include films for building glass, textiles designed for everyday use, and products such as membranes and automotive films.

Harnessing Nature for greater solar reflectivity

Designed for application on building surfaces and industrial equipment, this innovative coating boasts an impressive solar reflectivity and mid-infrared emissivity of up to 95%. By significantly reducing heat absorption, it surpasses the limitations of traditional coatings, which typically max out at 90% reflectivity. Application tests demonstrate that the coating can lower surface temperatures by as much as 42 degrees C, decrease indoor temperatures by 6-8 degrees C, and achieve overall energy savings of up to 40%.

Electricity-free cooling film

This high-performance film, crafted from advanced PET-optical material, is designed for glass curtain walls. With a mid-infrared emissivity of 94%, it effectively minimises heat infiltration while allowing ample light transmission. Data reveals that the film can reduce indoor temperatures by up to 15.4 degrees C, with an average decrease of at least 1.8 degrees C, providing a crucial solution for environments exposed to intense sunlight.

The TERA-Award

At the 2nd TERA-Award Smart Energy Innovation Competition, i2Cool proudly secured a USD 1 million prize for its electricity-free cooling technology. The judges praised the solution for its exceptional energy savings, emissions reduction, industrial feasibility and vast application potential – particularly its effectiveness in combating extreme heat and enhancing building energy efficiency.

Winning the TERA-Award has unlocked new avenues for collaboration. Since the award, our team has accelerated the deployment of the innovative technology, partnering with various industry leaders to explore its applications in green buildings, infrastructure and extreme environments.

Global impact and applications of electricity-free cooling technology

i2Cool’s electricity-free cooling technology has made significant strides, now deployed across 29 countries and regions, impacting sectors such as construction, logistics and sustainable urban development. These initiatives have fostered long-term, stable partnerships in local markets.

In the Middle East, i2Cool has partnered with EMAAR on iconic projects like the Dubai Mall – one of the world’s most visited shopping centres – where our electricity-free cooling coating was applied to the building surfaces to significantly reduce rooftop heat absorption. The coating lowered surface temperatures by an additional 10-20 degrees C, compared to previously used insulation materials and achieved energy savings of up to 20%. Additionally, i2Cool is collaborating on the Vision Tower project, further optimising building surface temperature control and reducing cooling energy consumption. In logistics, our technology has been trialled by Maersk for container transport, enhancing storage conditions for goods in high-temperature environments while lowering energy usage.

In Southeast Asia, large-scale pilot projects are underway in the Philippines and Vietnam, encompassing industrial factories and logistics warehouses. To expedite commercialisation, i2Cool is establishing a global distribution network, including exclusive agreements in the GCC region and Africa’s building sector with Leading Hospitality Services, a subsidiary of the UAE’s EIH Group; ongoing procurement efforts in Southeast Asia through distributors in Malaysia, the Philippines and Singapore; and a strategic partnership with Japan’s Marubeni Corporation to jointly promote the technology in international markets.

Electricity-free cooling technology has proven effective across a diverse range of sectors, delivering impactful benefits:

• Building and Infrastructure: Reduces heat load on exterior walls and roofs, enhancing indoor temperature control

• Industrial and Logistics: Improves storage and transportation conditions in high-temperature environments, ensuring product quality

• Renewable Energy and Photovoltaics: Optimises thermal management of photovoltaic modules, boosting power generation efficiency

• Textiles and Personal Protection: Integrated into functional fabrics to enhance comfort during hot weather

The technology is transforming how industries manage heat, driving energy efficiency and sustainability.

Advancing sustainability in urban development

Air conditioning systems account for approximately 20-40% of total energy consumption in buildings, worldwide, with even higher figures in hotter regions. The International Energy Agency (IEA) projects that global demand for cooling will surge, with air conditioning energy use expected to triple by 2050, becoming a primary driver of electricity load growth. Consequently, reducing reliance on traditional air conditioning and developing low- or zero-energy cooling technologies has become a key focus in global sustainable development strategies.

Electricity-free cooling is emerging as a vital solution for enhancing building energy efficiency and promoting urban sustainability. The environmental impact of conventional air conditioning extends beyond electricity consumption; most systems rely on refrigerants like hydrofluorocarbons (HFCs), which have extremely high global warming potential (GWP) and significantly contribute to climate change. With accelerating urbanisation, the building sector accounts for about 40% of global carbon emissions, with cooling and HVAC systems as major contributors.

To achieve low-carbon, sustainable cities and communities, reducing energy demand at the building level is essential. Many countries and cities are adopting “Zero Energy Buildings” (ZEBs) and “Nearly Zero Energy Buildings” (NZEBs) as standards for future development. Electricity-free cooling technology aligns seamlessly with these frameworks and can be integrated into green building certifications – such as LEED (Leadership in Energy and Environmental Design) and BREEAM (Building Research Establishment Environmental Assessment Method) – as a core strategy for reducing operational carbon emissions.

Outlook: Innovations, potential applications and product upgrades

The application of electricity-free cooling technology is expanding into everyday scenarii. For instance, fabrics with adjustable heat dissipation properties are being developed to create smarter personal protective equipment, enhancing comfort for outdoor workers and urban residents in high-temperature environments. Furthermore, by integrating advanced manufacturing technologies, i2Cool is advancing adaptive cooling materials for urban infrastructure, offering low-carbon solutions for the construction of future smart cities.

Pioneering Green Cooling

As the world moves toward carbon neutrality, green cooling has become an essential pillar of sustainable development. Electricity-free cooling solutions break through traditional energy consumption barriers, offering efficient, low-carbon alternatives for green buildings, industrial applications and personal protection. The innovation is facilitating the transition of cities and industries toward a more sustainable future.

Beyond reducing energy dependence, the technology redefines the cooling process, opening up new possibilities for addressing extreme heat on a global scale. As adoption grows and industries evolve, electricity-free cooling will continue to unlock transformative potential, accelerating the development of green cities and low-carbon societies.