Scientists Discover How to Generate Solar Power in the Dark

[NickB79]

http://news.yahoo.com/scientists-discover-generate-solar-power-172726044.html

Scientists at MIT and Harvard University have devised a way to store solar energy in molecules that can then be tapped to heat homes, water or used for cooking.

The best part: The molecules can store the heat forever and be endlessly re-used while emitting absolutely no greenhouse gases. Scientists remain a way’s off in building this perpetual heat machine but they have succeeded in the laboratory at demonstrating the viability of the phenomenon called photoswitching.

“Some molecules, known as photoswitches, can assume either of two different shapes, as if they had a hinge in the middle,” MIT researchers said in statement about the paper published in the journal Nature Chemistry. “Exposing them to sunlight causes them to absorb energy and jump from one configuration to the other, which is then stable for long periods of time.”

To liberate that energy all you have to do is expose the molecules to a small amount of light, heat or electricity and when they switch back to the other shape the emit heat. “In effect, they behave as rechargeable thermal batteries: taking in energy from the sun, storing it indefinitely, and then releasing it on demand,” the scientists said.

So, it's a thermal battery, not one capable of storing electricity, which kinda sucks. However, it could have numerous potential uses.

I'd love to build a greenhouse with such a system inside; charge all day in the sun, and then keep the interior toasty warm on cold Minnesota nights

[phantom power]

1. reminds me a little of these:

http://www.rewci.com/ez-heat-reusable-hand-warmer.html?gclid=CI3Wld2h6L0CFYc7Ogod92IA9w

Although they also charge using heat, they aren't photoswitches.

[Demeter]

2. Phase-changing materials were developed in the 70's

http://www.pcmproducts.net/Phase_Change_Material_Products.htm

eutectic salts

http://www.rgees.com/solutions_solar-thermal.php

[BlueStreak]

3. This might be a competitor to "flow batteries" someday

Flow batteries are a technology being investigated form grid-scale storage because the energy storage can scale up to as large as you want to build the holding tank. This might behave in a similar way (heat instead of direct current) with the advantage there would be no energy loss while stored..

It isn't clear that this technology would store energy densely enough to compete with batteries, considering that you would then have to convert the hear to electricity.