Posted on: April 28, 2019 Posted by: QUALQEM Comments: 0

Is There a More Efficient Way to Generate Clean Energy with Concentrating Solar Power?

Ever used a magnifying glass to focus sunlight on your hand?

Increase that heat a million-fold and you understand the concept of a solar thermal plant: a giant field of mirrors, focusing sunlight on a black metal chamber filled with water, air or other heat-carrying fluids. The concentrated sunlight is absorbed by the chamber walls and then conducted through the fluid, making it extremely hot. This concept can serve many purposes, including serving as reactors in chemical plants or converting sunlight into electricity in giant power plants.

So far, however, the energy output of solar thermal plants has been disappointing. Blame it on the tea kettle effect: When making water for tea, the hottest region is where the flames meet the exterior walls of the kettle. But what works well enough in the kitchen is a problem in large-scale applications like solar thermal plants because roughly half the solar energy is lost to the environment instead of being turned into usable energy.

Ali Mani, assistant professor of mechanical engineering at Stanford, is doing computer simulations to test what could be a more efficient way to use concentrated sunlight as a heat source. Instead of focusing sunlight on a black chamber, his lab is simulating what would happen if concentrated light were beamed into a transparent chamber, or tea kettle, to continue the analogy. In theory, photons of light passing through the clear chamber would collide with the fluid molecules inside, heating the fluid from within with significantly less energy loss.

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