Energy Nirvana on the horizon
A look at the issues shaping our industry
Tuesday, 22 Apr 2014 11:27 GMT
One of the biggest costs to any sign-maker is power, and it is not getting any cheaper. So what if you could reliably and cheaply generate all your needs for a relatively low capital investment? Or power ceased to be an ever-spiralling cost altogether? On top of that, what if you could use this technology to not only power signs for your clients, but actually be the sign at the same time?
Well, this Nirvana could be closer than you think. Backed by Semprius and tech-giant Siemens, a clever chap by the name of John Rogers from the University of Illinois has pioneered a new solar power technology that could render conventional silicon-based solar cells obsolete. They key problem with this latter system is that it is relatively inefficient, converting roughly only a quarter of the light that falls on its surface.
What if you could reliably and cheaply generate all your needs for a relatively low capital investment? Or power ceased to be an ever-spiralling cost altogether?”
Following its current trials at 14 sites around the world, Rogers’ says he fully expects his system to take the conversion ratio to 50 percent. The genius idea behind the systems design is that instead of using just one cell, it is four stacked together. In addition, each cell in the stack is made from a different conductive material. This means that instead of catching light photons of just one wave-length, it captures a much wider band, which increases the efficiency of electrical energy conversion.
A key stumbling block though is that these materials are much more expensive than that used in standard panels. Rogers has overcome this too though, by using less. Rather than semiconductor material that covers the solar-cell, his stacks only use 0.1 percent of its surface. And at 0.5mm square, the stacks are then scattered over the surface in a series of dots (roughly 4,000sq/m) with light focussed on them through basic glass lenses. And now for their ability to be signs too, the 99.9 percent of the surface not covered by stacks can have graphics printed on them and when viewed from any angle a full-colour image comes to life—whatever will they think of next?
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