Lonnie Johnson did risk assessment for the Atlantis space shuttle. He helped get the B-2 stealth bomber off the ground. He gave us the Super Soaker. And now, with his latest invention, he might just make solar power viable.
Johnson, a "self-invented inventor", is profiled in the November issue of The Atlantic, and while his Super Soaker revolutionised backyard shenanigans, his latest project, a unique heat engine called the Johnson Thermoelectric Energy Converter, or JTEC, could revolutionise the energy industry. And that's got some important people very excited.
Today's run-of-the-mill solar cells convert around 20 per cent of the solar energy they gather into electricity. The best solar systems we have can do about 30 per cent. The JTEC, which has no moving parts and produces no waste, could double that efficiency, making it competitive with coal. Paul Werbos, director of the National Science Foundation, says, "It has a darn good chance of being the best thing on Earth."
So how does the JTEC do what it does? A very elegant design and the second law of themodynamics:
Simply put, the law says that temperature differences tend to even out-for instance, when a hot mug of coffee disperses its heat into the cool air of a room. As the heat levels of the mug and the room come into balance, there is a transfer of energy.
Work can be extracted from that transfer. The most common way of doing this is with some form of heat engine...
...Johnson's latest JTEC prototype, which looks like a desktop model for a next-generation moonshine still, features two fuel-cell-like stacks, or chambers, filled with hydrogen gas and connected by steel tubes with round pressure gauges. Where a steam engine uses the heat generated by burning coal to create steam pressure and move mechanical elements, the JTEC uses heat (from the sun, for instance) to expand hydrogen atoms in one stack. The expanding atoms, each made up of a proton and an electron, split apart, and the freed electrons travel through an external circuit as electric current, charging a battery or performing some other useful work. Meanwhile the positively charged protons, also known as ions, squeeze through a specially designed proton-exchange membrane (one of the JTEC elements borrowed from fuel cells) and combine with the electrons on the other side, reconstituting the hydrogen, which is compressed and pumped back into the hot stack. As long as heat is supplied, the cycle continues indefinitely.
Johnson's currently wading through the swamp of bullshit that surrounds the act of invention - getting research grants, filing patents, trudging through peer review, etc - but energy experts familiar with the JTEC agree that's definitely something to get excited about. Read more about the JTEC and the man who invented it at The Atlantic. [The Atlantic]