The general idea of creating a structurally black surface on silicon or other photovoltaic is a sound one, both from the point of view of making the photovoltaic more efficient and for the secondary effect of using the unconverted light to make heat for storage.
What I find annoying in this article is the method of achieving that. So we have a group of whiz-bang boys from Harvard who are promoting a method that requires prohibitive amounts of energy to achieve this effect, when there are much more efficient and well-known ways of doing the same thing. I have a method of my own that works, not just for silicon, but for metals as well. These guys will suck up lots of venture capital because it sounds so high tech and they're "really smart guys". Ultimately the project will die unless a specialty niche is found for the product, but the people involved will go on to the next technical boondoggle to waste some more venture capital. If I were to contact these boneheads and tell them how to do this economically, they would ignore me completely and act like I was something that needed scraping from the bottom of their shoes. I speak from numerous experiences. M. --- On Sun, 6/28/09, Horace Heffner <[email protected]> wrote: > From: Horace Heffner <[email protected]> > Subject: [Vo]:Black Silicon > To: "Vortex-L" <[email protected]> > Date: Sunday, June 28, 2009, 10:55 PM > > http://cleantechnica.com/2008/10/12/black-silicon-could-revolutionize-solar-cell-technology/ > > http://tinyurl.com/3l733w > > > http://www3.interscience.wiley.com/journal/113445892/abstract?CRETRY=1&SRETRY=0 > > http://tinyurl.com/lreufb > > and of course google black silicon for much more. > > The high efficiency and low reflectivity of black silicon > makes it ideal for a hybrid electric - thermal solar systems > with thermal wells and heat pumps. > > I think heat pumps are best implemented as a hybrid thermal > well and solar system.. The temperature of thermal > wells stays well above ambient temperature. They are > very effective here in alaska. When combined with a > solar hot water collector, thermal solar energy in the day > can be used to heat the thermal well to store energy and > increase overall system efficiency. > > I think solar photovoltaic can integrate nicely with this > as well. Solar cells take about 15% of the solar radiation > for electrical energy production, but the left over energy > is still available as heat. Solar cell clad hot water (or > other heat collecting fluid) piping can thus be used to heat > a thermal well while simultaneously producing photovoltaic > energy for pumping the water. > > None of this is new thinking. The full integration of > such a hybrid system might be > though. Integrating solar thermal and > electric capture makes for double duty of each square foot > of roof space, which is critical for the economics of > rooftop systems. > > As photovoltaic efficiency increases the feasibility of > simultaneous hot/cold thermal storage becomes more > feasible. This is accomplished by compressing gas and > using a heat exchanger for hot storage and gas expansion to > freeze water for cold storage. Either hot > or cold storage can be tapped for heating or cooling as > needed, and both can be tapped for generating power via > sterling engine/generator. > > Some related comments regarding thermal energy storage > systems are here: > > http://www.mtaonline.net/~hheffner/HotCold.pdf > > Best regards, > > Horace Heffner > http://www.mtaonline.net/~hheffner/ > > > > >
