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Radiative Cooling in the Fight Against Climate Change

Climate change remains a pressing global challenge, impacting ecosystems, economies, and communities alike across the planet. As temperatures rise and extreme weather events become more frequent and powerful, innovative and scalable solutions are needed to mitigate the worst effects of the crisis. In this blog post, we will explore how passive daytime radiative cooling is uniquely positioned to play a pivotal role in the fight against climate change.

The Greenhouse Effect and Earth’s Energy Imbalance

The greenhouse effect is a natural phenomenon that maintains our planet’s temperature by trapping some of the sun’s energy in the atmosphere. Without it, earth would be cold and barren. Unfortunately, human activities, particularly the burning of fossil fuels, have artificially intensified this effect, leading to our current issue with a quickly warming globe. By adding billions of tons of greenhouse gasses to our atmosphere every year, we have created an energy imbalance in our atmosphere. More of the sun’s energy is entering our atmosphere than is escaping it, contributing to global temperature increases and an uncertain climate future. 

Global average temperature change chart
RCraig09, CC BY-SA 4.0, via Wikimedia Commons

Air Conditioners: An Imperfect Solution

We can’t air condition ourselves out of climate change. The refrigerants used in air conditioners are potent greenhouse gasses themselves, with roughly two thousand times the potency of carbon dioxide. While air conditioners are supposed to be closed systems, as small leaks develop over time, the refrigerants escape into the atmosphere.

As of 2023, 75% of the electricity used by our energy-hungry air conditioners still comes from fossil fuels. Finally, our air conditioners don’t create cold. Instead, they pump heat from inside a building to the outdoors. That’s great for the occupants of an air conditioned building, but not so great for the people and animals walking past the outdoor unit as it pumps concentrated heat into the neighborhood. The unfortunate reality is that our current cooling systems are contributing to heating the globe.

A Growing Demand for Air Conditioning

Air conditioning has transformed our lives, making our indoor environments more comfortable and safer during extreme heat waves. However, this comfort comes at a cost, with cooling accounting for nearly 20% of building electricity use across the globe. Further, the global demand for air conditioning is surging and is forecast to grow by 400% from 2020 levels by the year 2050. This trend is driven by three major factors: climate change, urbanization, and economic development. 

As temperatures continue to rise due to climate change, cooling in many areas has transformed from a luxury into a requirement for human civilization. With rapid urbanization, more people are living in denser and hotter cities. Urban areas, in part due to the heat-absorbing properties of surfaces like blacktop, tend to remain 3°F-10°F warmer than surrounding rural regions. This is a phenomenon known as the urban heat island effect. Moreover, economic development of Sub-Saharan Africa, India and South-East Asia has resulted in soaring demand for air conditioning units, as a growing global middle class can now afford the associated installation and electricity costs.

Of course, it is all with good reason. Air conditioning significantly improves human comfort, productivity, and health in hot regions. In fact, in school districts without air conditioning, a 1°F increase in average school year temperature was found to be associated with a 1% decrease in learning! The solution to our air conditioning problem is not found in human suffering by locking out the thermostat, but in innovative and efficient improvements to the ways that we stay cool and comfortable.

A New Climate Friendly Solution

Passive daytime radiative cooling (PDRC) offers a cold ray of hope in the fight against climate change. The technology harnesses radiative cooling principles to naturally release heat from surfaces during daylight hours. If you want a quick refresher, check out our article titled: “The Science of Radiative Cooling: How Does it Work?” PDRC provides several compelling advantages:

Energy Efficiency: PDRC cools surfaces with zero-energy, effectively reducing electricity consumption and subsequently lowering greenhouse gas emissions.

Climate Resilience: PDRC can combat the urban heat island effect, mitigating extreme temperatures in dense urban areas.

Affordability: The energy cost savings associated with PDRC can significantly benefit households and businesses, making it an accessible and cost-effective solution.

Mitigating Climate Change: The Prerequisites for Scale

In order for any technology to have a measurable impact on the urban heat island effect and climate change, it must be able to be deployed at scale. Scalable technologies must meet the following criteria:

Efficient Use of Materials: The technology should minimize its resource consumption and waste, ensuring that it uses materials efficiently. This helps reduce the overall environmental footprint and supports sustainability. The entire lifespan of a technology must be considered, from manufacturer all the way through the end of life to waste management or recycling of the materials.

Cost Effective: Scalable technologies must be economically viable, both in terms of initial setup costs and long-term maintenance. They should offer a compelling return on investment, making them attractive to investors, governments, and businesses.

Easy to Install: The technology should have a straightforward and user-friendly installation process. This minimizes the time and effort required for deployment and encourages its adoption across various settings and applications.

Easy Substitution Into Existing Markets: For a technology to be scalable, it should integrate seamlessly into existing markets and infrastructures. This reduces barriers to adoption and encourages a smooth transition toward more sustainable practices without causing significant disruption.

PDRC materials meet all of the above criteria. A single roll of our PDRC film weighs under 50 pounds and provides 8,500 watts of continuous cooling for over a decade. PDRC materials are incredibly thin and made from layers of common materials like high density polyethylene (the same plastic that soda bottles are made from) and silver. With zero operational electricity or water inputs, an expected lifespan over a decade, and existing recycling streams to process end-of-life product, PDRC is the most material efficient form of cooling that exists today.

It is cost effective, being cheap to manufacture and install and requiring almost zero maintenance and ongoing operation costs. PDRC offers attractive returns on investment in a multitude of applications and industries. By directly saving energy in the form of electricity or fuel, lowering capital outlay and maintenance requirements for traditional expensive cooling systems like air conditioners, and increasing economic efficiency in various industrial applications, PDRC often sees payback periods of between one and three years.

It is also incredibly easy to install. Our PDRC films and membranes have a simple peel and stick backing and installation can be done by a single person or small team. Roof films and membranes can be retrofitted onto existing structures or added onto roofing materials during initial fabrication. Window films follow existing tint installation processes already employed by the existing window tint industry.

Finally, our PDRC products can be substituted almost perfectly into existing markets and applications. Roof and window films can be added to pre-fabricated products during manufacture or retrofitted on-site. PDRC fabrics, available in a large variety of materials, weights, and weaves, can be substituted directly into almost any existing fabric product with few changes to the manufacturing processes. 

With all criteria met, PDRC is ready to scale. The next question then is: what will PDRC look like at various scales, and what level of adoption do we need to start seeing an impact on global warming?

What Does PDRC Look Like at Scale?

Local Deployments: Localized deployments can yield immediate benefits, reducing average and peak energy consumption and curbing the urban heat island effect in metropolitan areas.

National Initiatives: Countries can implement PDRC at the national level, focusing on cooling solutions for urban and rural environments, thus impacting their national energy consumption and resilience.

Global Strategies: A global-scale deployment would have the most significant impact, effectively rebalancing the Earth’s energy budget and helping to mitigate climate change. This approach involves extensive collaboration among nations and significant financial investments.

The good news is that passive daytime radiative cooling provides both local and global benefits, regardless of scale. Like solar power, every PDRC installation helps us reduce our reliance on fossil fuels. Because of this scalability, we believe that passive daytime radiative cooling will have one of largest technological impacts on climate change mitigation in the 21st century.

Ready to Jumpstart PDRC Adoption?

Coldrays is America’s first large-scale distributor of passive daytime radiative cooling materials. We are always on the lookout for partners with a shared vision for a better planet. Check out our passive daytime radiative cooling products or get in touch to learn more about building the future.

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Chris Hiller
Chris Hiller
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