Energy lab says flat solar panels may be option
by Eric Mortenson – The Oregonian – June 12, 2009

Flat solar panels could fit on roofs like shingles. A transparent thin film barrier used to protect flat panel TVs from moisture could become the basis for flexible solar panels that would be installed on roofs like shingles.

Researchers at the Department of Energy’s Pacific Northwest National Laboratory in Richland, Wash., are working on flexible rooftop solar panels.

The panels — called building-integrated photovoltaics, or BIPVs — could replace boxy solar panels that are made with rigid glass or silicon and mounted on thick metal frames. The flexible solar shingles would be less expensive to install than current panels, and made to last 25 years.

“There’s a lot of wasted space on rooftops that could actually be used to generate power,” senior scientist Mark Gross said in a news release. “Flexible solar panels could easily become integrated into the architecture of commercial buildings and homes. Solar panels have had limited success because they’ve been difficult and expensive to install.”

Researchers at PNNL will create these flexible panels by adapting a film encapsulation process currently used to coat flat panel displays that use organic light-emitting diodes, or OLEDs. The work is made possible by a Cooperative Research and Development Agreement recently penned between Vitex Systems and Battelle, which operates PNNL for the federal government.

Laboratory researchers developed the thin film technology in the 1990s. At the time, the lab’s team investigated 15 possible applications, including solar power. Vitex licensed the technology from Battelle in 2000 and focused its initial efforts on developing the ultra-barrier films for flat-panel displays. Now PNNL and Vitex are taking a hard second look at solar power.

PVT Solar, the company spotlighted in the article below is not the only company that combines photovoltaic technology and thermal energy to produce more energy than the PV alone.

SolarWall, an international company with headquarters in Toronto, Ontario, has developed a number of products based on its original air heating wall system including combining the thermal wall with photovoltaics to create their SolarDuct PV/T and SolarWall PV/T products.

The SolarWall PV thermal (PV/T) co-generation system was tested at the Canadian National Solar Test Facility.  The results showed that by adding a solar thermal component to a PV array to capture excess heat the total solar efficiency was boosted to over 50%, comparied with 10 to 15% efficiency that is typical of most stand-alone PV modules.

It’s clear, given the cost of PV panels, that every amount of available energy produced by the panels including thermal energy will need to be captured and put to use in order to provide economically saleable systems.

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Waste Not, Want Not: A New Approach to Solar
By Matthew L. Wald – New York Times – September 29, 2008

One of the limitations of solar photovoltaic systems is that, at the current state of the technology, no more than a quarter of the energy from the sun is converted to electric current. Most of the rest of the energy is lost as waste heat.

But Vinod Khosla, the founder of Sun Microsystems and now a technology entrepreneur and alternative-energy venture capitalist, says he’s found a solution that doubles or even triples the energy yield — a gargantuan leap in a field where engineers exult over the most incremental gains.

Mr. Khosla is funding a company called PVT Solar, of Berkeley, Calif., where engineers two years ago began trying to harness that wasted heat. In a sense, it was already being collected, either in the solar modules themselves, or underneath. (Solar arrays are often installed at an angle, to face the sun, thus creating a wedge-shaped space below for heat to collect.)

PVT’s founders decided the heat could be harnessed and pumped into the home for climate control, water heating and other uses. It is a sort of combined cycle for solar — a marriage of solar photovoltaic technology and solar thermal systems, which gather the sun’s energy in the form of heat.

Vinod Khosla, the former tech mogul and now energy venture capitalist, sees potential in PVT Solar. (Photo: Bloomberg)The company is currently testing electronic controllers that play traffic cop for the collected heat, pumping it automatically, using a small fan, to the basement hot-water heater, for example, or to individual rooms, or even to the swimming pool, as needs arise. If the heat is not needed in the building, the fan vents it to the outside.

Because solar panels perform better at cooler temperatures, removing heat from around the panels also has the effect of increasing their production on hot days — adding to the overall efficiency gains for the system.

And given that the system requires little or no additional infrastructure, it can be deployed with only a small amount of added cost.

The company, which remains skittish about sharing details, is still making refinements, including the possible placement of stones beneath the panels, if rooftops can support them. Stones, the engineers reckon, could absorb the heat and act as storage devices.

Gordon Handelsman, president of the company, said that he has installed “more than ten and less than 20″ PVT systems at this stage, though he was so apprehensive about the company’s intellectual property that he took down his Web site after receiving a call from this reporter.

“We make around 100 percent more energy than a regular PV system,” he said.

For his part, Mr. Khosla said that making use of the otherwise wasted heat can increase total system efficiency to over 50 percent. “Now the economics make sense,” he said.

There is no argument that conservation is the most effective way to reduce energy consumption.  But, just as we cannot drill our way out of the constant demand for oil, we cannot conserve or build our way out of the constant demand for the energy to heat and cool our homes and buildings.  By using green building techniques we can have a substantial effect on reducing energy consumption but it appears that no matter how much energy we conserve there will always be the demand for more and more energy.

By combining energy conservation, green building (and remodeling) techniques plus active and passive energy generation we can have the best of all worlds. 

One way to accomplish combining active and passive energy generation is to utilize Building Integrated Photovoltaics (BIPV).  These are building materials that are capable of actively generating electical energy via built-in photovoltaics.  An example of a BIPV application are the skylights of the Boulder, Colorado REI store.

SolarWall, an international company with headquarters in Toronto, Ontario, has developed a number of products based on its original air heating wall system including combining the thermal wall with photovoltaics to create their SolarDuct PV/T and SolarWall PV/T products.

The SolarWall PV thermal (PV/T) co-generation system was tested at the Canadian National Solar Test Facility.  The results showed that by adding a solar thermal component to a PV array to capture excess heat the total solar efficiency was boosted to over 50%, comparied with 10 to 15% efficiency that is typical of most stand-alone PV modules.