Super Soaker Inventor Aims to Cut Solar Costs in Half

Posted on January 9, 2008  Comments (1)

Super Soaker Inventor Aims to Cut Solar Costs in Half

[Lonnie ] Johnson, a nuclear engineer who holds more than 100 patents, calls his invention the Johnson Thermoelectric Energy Conversion System, or JTEC for short. This is not PV technology, in which semiconducting silicon converts light into electricity. And unlike a Stirling engine, in which pistons are powered by the expansion and compression of a contained gas, there are no moving parts in the JTEC. It’s sort of 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.

Here’s how it works: One MEA stack is coupled to a high- temperature heat source (such as solar heat concentrated by mirrors), and the other to a low-temperature heat sink (ambient air). The low-temperature stack acts as the compressor stage while the high-temperature stack functions as the power stage. Once the cycle is started by the electrical jolt, the resulting pressure differential produces voltage across each of the MEA stacks. The higher voltage at the high-temperature stack forces the low-temperature stack to pump hydrogen from low pressure to high pressure, maintaining the pressure differential. Meanwhile hydrogen passing through the high-temperature stack generates power.

“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.”

Very cool and yet another example of the benefits of educated engineers. The positive externalities are large for engineering education.

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One Response to “Super Soaker Inventor Aims to Cut Solar Costs in Half”

  1. CuriousCat: Seventh-grader's Solar Cell Research
    September 21st, 2008 @ 5:10 pm

    “He is our youngest fellow in science that we’ve ever had,” Moessner said. “He is really spectacular. “His project will really make a difference in advancing the technology of solar cells. You would never know he’s 12 looking at the quality of his work…

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