All About Solar | Green Energy News

March 13, 2005 – Vol.9 No.51

ALL ABOUT SOLAR.

Solar cells generate DC (direct current) power that must be converted to AC (alternating current) by an inverter to be compatible with the power in our homes and businesses.

But, if all the electric appliances, heating and cooling systems, lights, etc in our buildings ran on DC, then solar electricity wouldn’t have to be converted. The cost of solar systems would drop and efficiency would improve. (Inverters consume electricity thus reduce the overall efficiency of a solar system.)

Nextek Power now has an additional reason for converting buildings to run on direct current. At least in California, DC solar systems using Nextek’s Direct Coupled (tm) system don’t need special permission from the local electric utility for a grid interconnect, at least in commercial applications.

When a Nextek system is installed, all of the electrical systems in a building are converted to DC. Fluorescent lighting ballasts are replaced by high-efficiency DC ballasts for 98 percent efficiency. Electric motors are converted to DC and other DC systems are created, such as circuits for computers.

In operation if solar electricity is available it is used first to power the building. If not, a back-up power supply such as batteries is tapped and finally, electric power is taken from the grid as a last resort.

The California Energy Commission Rule 21 Working Group made it legal for Nextek’s Direct Coupled Systems to be grid connected without an array of permissions. Visit Nextek at http://www.nextekpower.com/ .

Typically, solar cells convert only certain wavelengths of light to electricity. This is one reason solar cells are not very efficient. Some cells have increased efficiency by using multiple crystals in each cell - each to grab a different wavelength of light. Multicrystalline cells tend to be more expensive than those with a single crystal, however.

Another way to make solar cells more efficient may be to grab only the solar wavelengths that can be converted by the cell and concentrate that light. That is, soak the cell with as much as one or a few wavelengths of light as possible and disregard the rest.

Direct Global Power (DGP), by attaining an exclusive license to a technology from the Illinois Institute of Technology known as Holographic Planar Concentrator (HPC) will be working to further develop it with the goal of bringing down the cost of solar energy.

Direct Global Power describes the technology as a holographic film used to spectrally select targeted wavelengths and direct them onto the cells creating a passive concentrator and tracking capability. DGP also says that cells using the technology can be bifacial. Light shining in from both sides of the cell can be converted to electricity for greater efficiencies.

Visit Direct Global Power at http://www.directglobalpower.com/ .