Sunflowers and Yard Waste Inspire Efficient Solar Systems


(Image Credit: Inhabitat)

Drawing inspiration from sunflowers to find more efficient ways to harvest solar energy, UW-Madison electrical and computer engineer and engineering professor Hongrui Jiang has used the concept of heliotropism in the next crop of solar power systems. An adaptation called heliotropism that enables each leaf to seek out as much sunlight as possible explains why a field of young sunflowers will slowly rotate from east to west during the course of a sunny day.

Published in Advanced Functional Materials in August and recently highlighted in Nature, Hongrui Jiang’s concept is a clever bit of natural engineering that leverages the properties of unique materials in concert to create a passive method of re-orienting solar panels in the direction of the most direct sunlight. It employs a combination of liquid crystalline elastomer (LCE) which goes through a phase change and contracts in the presence of heat absorbed by carbon nanotubes over a wide range of light wavelengths that causes the entire assembly to bow in the direction of the strongest sunlight . The system improved the efficiency of solar panels by 10 percent and with no motors and circuits to eat into increased energy harvest; the electricity output of the passive system is increased through solar tracking.

Here’s Dr. Jiang’s proof of concept in action:

Yard Waste Goes Solar?

Andreas Mershin, research affiliate at the Massachusetts Institute of Technology, or MIT Centre for Bits and Atoms managed to create solar panels from agricultural waste a few months ago. He discovered a new way of harnessing the sun by isolating the photosynthesising molecules called Photosystem I from plant matter that contains chlorophyll.


(Image Credit: Cleantechnica)

The project involved isolating the plant protein that converts sunlight into energy, focusing on it, and transforming it into electrons. Though chlorophyll isolation has been done successfully by other scientists, the challenged was to find a way to stabilise it, so it did not degrade into dead matter when isolated from the living mass of the plant.

Mershin has convert nature’s solar panels or leaves into man-made solar panels that can now be used to generate electricity. Though it a fantastic and non-disruptive way of harnessing solar power for electricity, scientists have to find a way to ensure that these cells continue operating and making energy. A mixture of titanium dioxide and the stabilised ‘Photosystem I’ converts the sun’s rays into electricity when it is spread on a glass substrate and the forest of zinc-oxide nanowires transports the electricity that can be used to charge a battery.

Listen to Merchin discuss his theories in this video from MIT: