Tuesday, January 8, 2008

Super Soaker Inventor Aims to Double Solar Efficiency

Super Soaker Factory (TGW) - You’ve heard about advances in solar power before, but coming from the inventor of the super soaker?

Lonnie Johnson, the inventor of the super soaker, says he can achieve a conversion efficiency rate that tops 60 percent with a new solid-state heat engine.

Most photovoltaic materials have around a 30% conversion rate. In case you failed elementary school math, that’s double the current average.

Johnson, a nuclear engineer with more than 100 patents, calls his invention the Johnson Thermoelectric Energy Conversion System (JTEC).

JTEC isn’t photovoltaic; it’s more like a fuel cell.

JTEC circulates hydrogen between two membrane-electrode assemblies (MEA). Unlike a fuel cell, however, JTEC is a closed system. No external hydrogen source. No oxygen input. No wastewater output. Other than a jolt of electricity that acts like the ignition spark in an internal-combustion engine, the only input is heat.

The system works by using temperature differences in different areas to manipulate pressure in the system. One area is ultra hot and potentially heated by the sun. The cycling heat and cold produces voltage across the MEA stacks. The high voltage moves hydrogen across a stack, creating energy.

“It’s like a conventional heat engine,” explains Paul Werbos, program director at the National Science Foundation, which has provided funding for JTEC. “It still uses temperature differences to create pressure gradients. Only instead of using those pressure gradients to move an axle or wheel, he’s using them to force ions through a membrane. It’s a totally new way of generating electricity from heat.”

Using the theoretical Carnot thermodynamic cycle, a 60% efficiency rating can be predicted.

The engine can operate on tiny scales or on megawatt scales. The promise lies in the source of the heat. The heat could not only come from the sun, excess heat, or even from the human body.

Via :: Popular Mechanics