Building Air Conditioning ( Solar Thermal Magazine)
Imagine a technology that reflects the sun’s rays away from a building while allowing excess heat to leave there by keeping the building cool without the need for air conditioning. A team at Stanford University has done just that. This energy-saving breakthrough was reported in the journal Nature by A team led by electrical engineering Professor Shanhui Fan at Stanford University.
Here is how it works.
Heat can be transferred in three ways:
1- conduction, convection and radiation. Conduction transfers heat by touch which is why you do not want to touch a hot surface.
2- Convection transfers heat by movement of fluids or air like you feel when you step into a hot shower or open the door to a hot oven.
3- Radiation which transfers heat in the form of infrared light that emanates outward from objects.
The Stanford team calls photonic radiative cooling which is a 2 step process that offloads infrared heat from within a building while also reflecting the sunlight that would otherwise warm it up. The result is cooler buildings that require less air conditioning.
“This is very novel and an extraordinarily simple idea,” said Eli Yablonovitch, a professor of engineering at the University of California, Berkeley, and a pioneer of photonics who directs the Center for Energy Efficient Electronics Science.
As a result of professor Fan’s work, we can now [use radiative cooling], not only at night but counter-intuitively in the daytime as well.
“This team has shown how to passively cool structures by simply radiating heat into the cold darkness of space,” said Nobel Prize-winning physicist Burton Richter, professor emeritus at Stanford and former director of the research facility now called the SLAC National Accelerator Laboratory.
This may mean that buildings on the future may not need air conditioning at all!
Photo credit: https://news.stanford.edu/pr/2014/images/cooling_illustration.jpg
About Gordon Smith
Gordon’s expertise in the area of industrial energy efficiency and alternative energy. He is an experienced electrical engineer with a Masters degree in Alternative Energy technology. He is the co-founder of several renewable energy media sites including Solar Thermal Magazine.