Cool companies at Cleantech 2007

Sure, Vinod keynoted.

And yes, there were the obligatory panels of VCs and other pundits... including a session led by yours truly.

But Cleantech 2007, which kicked off today in the heart of Silicon Valley, took a markedly more scientific slant than your average cleantech event.

In the most dramatic illustration of its technical focus, instead of traditional vendor exhibits, at several points in the day attendees were invited to lose themselves in a veritable maze of more than a hundred modest, academic symposium-style tabletop displays. It was a refreshingly low tech, low-glitz opportunity to ask researchers and nascent startups about what they were doing.

There was nary a booth bunny in sight.

While the majority of the exhibits were nanotech-focused, given that the show was co-hosted with a larger nanotech event, a little digging uncovered some potential cleantech jems.

So, herewith, we thought it would be fun to bring you three of the most interesting startup companies we talked to—three that we'll bet you've never heard of.

Aphios - Biomass pretreatment for cellulosic biofuels

Boston-based Aphios, a biopharmaceutical company, has come up with a way to possibly make the first stage of cellulosic biofuel easier, cheaper and less water-intensive.

In converting cellulosic mass to fuel, enzymes have to navigate the tightly woven fibers of cellulosic biomass to do their work. Today, cellulosic materials are typically pretreated by acid hydrolysis or "steam explosion." Both methods are energy-intensive, and require large amounts of water to flush the materials so that the enzymes aren't harmed by the pretreatment. (Interested in the details of how cellulosic ethanol is being made today? Download and listen to the archive of the Cleantech Group's web seminar What's real and what's not in cellulosic biofuels.)

Aphios' "critical fluid combination", or CFC process, uses carbon dioxide produced from the ethanol fermentation step, as well as a small amount of ethanol itself, to expand the cellulosic fibers and make them accessible.

"Plus, we get added benefit because the carbon dioxide dissolves in the water and causes massive amounts of carbonic acid," said Trevor P. Castor, president and CEO, to the Cleantech Group.

Castor claims his process can get a 300% improvement in enzymatic conversion efficiency versus steam explosion, and 60% better than acid hydrolysis pretreatment. For less money than either.

The company has a pilot project at a power plant in its hometown of Woburn, Mass., and says it has not yet been "shaking the tree" to find more customers.

Ah. Tree. Cellulosic. We get it.

Advanced Energy Products - Night Breeze

Davis, California-based Advanced Energy Products is using relatively low tech, at a relatively low cost, to lower new homes' heating and cooling bills.

The company's Night Breeze system cools homes on hot summer nights by essentially venting the house to cooler outside air, if it indeed is cooler (the system is smart enough to know.) It heats homes, when needed, using heat from the water heater, or conventional gas furnace.

By analyzing the last few days of data, the controller is smart enough to predict the next day's temperatures, and passively heat or cool the house overnight to maximize the home's ability to cope with the next day's temperature using a minimum of power, explained Don Logsdon, VP of sales and marketing.

The system involves software and simple ducting and fan hardware. It is only available at this time to new home builders, but retrofit kits for existing homes will be available soon, said company president Mark Berman.

Night Breeze only costs "a few thousand dollars", and pays for itself within a few years, the company said.

Innovative Thin Films - a self-cleaning coating for solar panels

Dirty solar panels are more than just an eyesore. They're less effective, with power loss ranging between 5-20 percent.

Knowing this, solar installers often factor in 5-20 percent more panels than an installation should take, just so the customer gets the rated value of the system they're buying, according to Innovative Thin Films of Toledo, Ohio.

The company, co-founded by chemistry professor Dean Giolando of the University of Toledo, has developed a nanotechnology-based thin film that, when applied to the surface of a solar module, "turns conventional grime into CO2 and water, using a small amount of UV light," according to professor Giolando.

The result? For an added cost of an estimated $2.10 per square meter, and no loss in light to the panel, solar modules can stay clean perpetually, in theory. And solar installers can, in theory, sell smaller, "right-sized" systems, for lower cost (or not).

Giolando is quick to point out that testing is not complete. The durability of the material is unknown, he admits. But the company's initial prototype equipment is at least able to apply the film to solar modules at assembly line speeds.

If it works, and lasts in the harsh environment of real world roofs, it could be an exciting product. Not to mention help put the clean in cleantech.