Solar Hydrogen Energy Corporation (SHEC) Labs, a renewable energy research and development company, has the distinction of creating the most efficient solar thermal technology in the world, jumping ahead of a group at MIT also working on boosting solar thermal efficiency. 

Concentrating solar power (CSP), or solar thermal, technology magnifies sunlight with mirrors or lenses and uses tracking systems to focus the light.  The concentrated light can be used as a heat source for any number of applications, including conventional power plants.  Typically, this entails heating a working fluid such as steam or a hydraulic fluid.

First, a couple of staggering stats:  SHEC’s solar concentrator can concentrate solar energy up to 5,000 times the ordinary intensity of sunlight as it reaches the earth (the MIT technology concentrates by a factor of 1,000).  The heat can reach a temperature of 11,000 degrees Fahrenheit and can instantly melt metal if the concentrated sunlight is focused on it.

A CSP system has two major components.  The first is the solar concentrator (the mirror or lens), which often takes the form of a parabolic or trough-shaped reflector. 

The second is the receiver, typically a tube with an aperture and a reflective coating.  The concentrator directs the concentrated sunlight through the aperture, the sunlight bounces around within the receiver, and the energy is eventually absorbed.

SHEC has filed two patent applications, one for its solar concentrator and one for the receiver.  U.S. Patent Application Pub. No. 2008/0060636 (‘636 application) is directed to a solar concentrator having a shutter apparatus with a plurality of movable shutter plates (10) arranged around a central aperture (14). 

A shutter drive moves the plates between the open and closed positions.  When a shutter plate is in the closed position, it blocks only a portion of the aperture. 

By controlling how many and which plates close, varying portions of the solar beam can be blocked and prevented from entering the receiver.  In additon to traveling through the center aperture, the sunlight can pass between the edges of the shutter plates.

The concentrator also has a cooling circuit which circulates cooling fluid to prevent potential damage to the shutter plates from the heat of sun.

According to the ‘636 application, this design allows finer control over the amount of heat energy directed to the receiver.  This is important because many existing solar receivers include boilers or thermal reactors that have no throttle-type control to assure that the energy supplied corresponds to the load of the engine. 

Thus, if the load drops and the solar energy supplied remains constant, the engine overheats and sustains damage.  Prior solutions included movable mirror segments with many complex moving parts, and shutter plates which were often fragile and subject to damage from the elements.  The ‘636 application provides a more elegant solution.

U.S. Patent Applicaton Pub. No. 2008/0184990 (‘990 application) covers an apparatus for collecting heat from a solar concentrator.  The receiver has an isothermal (i.e., maintaining a constant temperature) body and an elongated cavity.  

A key feature of SHEC’s receiver is that the circular aperture has a diameter equal to the diameter of the focused sunlight reflected by the solar concentrator and is located at the focus point of the concentrator.  This minimizes parasitic losses of sunlight and substantially boosts efficiency.

Not surprisingly, according to this Ecogeek piece, SHEC’s super efficient CSP system already has a couple of buyers.  From an IP perspective, SHEC’s duo of complementary patent applications offers a good illustration of how to divide a new system into its key components and pursue patent protection for each.

• Previous Entry: Pratt & Whitney’s Geared Turbofan Engine
• Next Entry: HP and Be Green Packaging Become Certifiably Green