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Insights on how you can protect the environment, maintain and increase the value of your company, through a structured process.

Home / interviews / Using today the method ancient people used outer space to make ice in desert conditions.

Using today the method ancient people used outer space to make ice in desert conditions.



Simon Pitsillides (SustainCase Editor):

Interview with SkyCool Systems’s George Keiser


Tell us a bit about the team behind SkyCool Systems.

George Keiser: SkyCool Systems was founded in 2016 by 3 co-founders: Eli Goldstein, CEO, Aaswath Raman, Chief Science Officer, and Shanhui Fan, a Stanford professor of electrical engineering and advisor to SkyCool. Since then, the team has grown to build and scale electricity-free cooling. SkyCool Systems is a team of dedicated engineers, scientists and business operators that are passionate about mitigating the effects of global warming and using the company’s technology to reduce rising temperatures around the world.


What is the problem/ challenge we are facing as humanity?

GK: The demand for cooling is on a rapid growth trend. On a global scale, air conditioning and refrigeration systems consume massive amounts of energy and discharge significant amounts of greenhouse gases to our planet. The International Energy Agency expects energy demand for space cooling to triple by 2050. If left unchecked, the electricity used to power cooling systems will overburden electrical grids and increase plant-warming emissions. We’re on a continuous feedback trajectory where, as the world gets hotter, demand for cooling increases, which then compounds the problem by amplifying the effects of climate forcings. We need new solutions to keep the world cool.

How did ancient people use outer space to make ice in desert conditions and at +5 ° C (above freezing conditions)?

GK: Radiative sky cooling occurs naturally because Earth’s atmosphere is partially transparent to infrared thermal radiation (the light wavelength associated with heat). As a result, sky-facing surfaces emit more energy as thermal radiation to the sky than they receive from it. Radiative sky cooling occurs at night as all objects emit thermal heat. Ancient Persians and Egyptians learned to use radiative night sky cooling to make ice in the desert. More information can be found here –


How have you structured materials to take advantage of radiative cooling to transmit heat into space even during daytime?

GK: Prior to SkyCool’s work, the effect of radiative cooling was not observed during the day because the sun heats up all outdoor, sky-facing surfaces. SkyCool Systems has come up with a patented, daytime radiative cooling approach that employs multilayered films to reflect nearly all incident sunlight across the solar spectrum and also emit energy in the mid infrared frequency range between 8 and 13 micrometers. Using the films, SkyCool has developed panels that reject heat to the sky, and are capable of cooling fluid. The cooling effect from our panels is enabled by the optical film, which covers the top of the panels. The film reflects sunlight to prevent the panels from heating up during the day and also emits infrared heat to the cold sky, which cools the panels and the fluid running through the panels.


Who benefits from this? How can businesses utilise your solutions to save energy and reduce emissions?

GK: The cooling effect from our panels occurs all day and is very well aligned with the 24/7 operation of refrigeration and air conditioning systems in supermarkets, refrigerated warehouses, data centers, hospitals, convenience stores, office buildings, and restaurants with walk in freezers. Panels can be integrated with air conditioning and refrigeration systems, or even operate as a complete AC replacement.


Are your solutions readily available for businesses? (If not, what is the timeline?)

GK: Yes, we are currently working on deploying our technology in the commercial and industrial refrigeration market. We have completed pilot demonstrations with key partners to demonstrate efficiency as an add-on and are now working on scaling deployments.


Where can we see the solutions you provide?

GK: We’ve completed several commercial demonstrations with partners in California and are continuing to roll out our technology with key partners around the globe.


Which are the future possible applications of your solutions and what are the benefits?

GK: Besides the applications listed above, SkyCool panels could also be combined with radiant cooling in efficient buildings to completely replace an air conditioning unit. In addition, radiative cooling film can be applied directly to building materials such as roofing. This can be used to reduce heat loads of roofs, bus shelters/shaded structures, outdoor batteries and electronic boxes, and automobiles. For customers in the commercial and industrial cooling markets, we are helping save energy and reduce GHG emissions. Our panel system also provide capacity savings and demand savings.


What is the issue with photovoltaic panels at the moment and how can they be made more efficient?

GK: We do not currently do any work with photovoltaic panels.


What are your major challenges and how are you overcoming these?

GK: As we work to scale the business, we’re  working to educate customers on the technology and opportunity. We’ve encountered lack of awareness of energy efficiency opportunities and conservativeness towards adoption of new technologies. To overcome these, we are currently collecting data and creating case studies to document and communicate the value-add of our technology.


How do your solutions disrupt things?

GK: Our core innovation is a radiative cooling material that we’ve combined with a panel system to improve the efficiency of any vapor-compression based cooling system. We’re using this innovative technology to help our customers save money and prevent the emission of CO2 and other harmful greenhouse gases. Radiative cooling is one of a very small number of truly game changing technologies to emerge in the area of cooling. This is a space that will have major impacts on future electricity loads and contributions to atmospheric GHG levels.


Future targets/ applications. 
1. To integrate these kinds of panels with higher efficiency building cooling systems to reduce their energy usage by two-thirds.
2. Build a cooling system that requires no electricity input at all.
3. Use the cold darkness of space to improve the efficiency of every energy-related process here on earth. For example, photovoltaics which when they heat up under the sun and become less efficient the hotter, they are.
4. Help with water conservation
5. Directly generate power with the cold of space.

More information at:


Watch the talk on

What if we could use the cold darkness of outer space to cool buildings on earth? In this mind-blowing talk, physicist Aaswath Raman details the technology developed to harness “night-sky cooling” — a natural phenomenon where infrared light escapes earth and heads to space, carrying heat along with it — which dramatically reduces the energy used by our cooling systems (and the pollution they cause). Learn more about how this approach could lead us towards a future where we intelligently tap into the energy of the universe.