Skip to comments.Scientists convert heat into electricity
Posted on 06/04/2007 12:36:33 PM PDT by nypokerface
SALT LAKE CITY, June 4 (UPI) -- U.S. scientists have developed a technology that converts heat into sound and then into electricity.
University of Utah physicist Orest Symko said the technology also holds promise for harnessing solar energy and cooling computers and radars.
"We are converting waste heat to electricity in an efficient, simple way by using sound," said Symko. "It is a new source of renewable energy from waste heat."
Symko plans to test the technology within a year to produce electricity from waste heat at a military radar facility and at the university's hot-water-generating plant.
The research is funded by the U.S. Army, which is interested in "taking care of waste heat from radar and also producing a portable source of electrical energy which you can use in the battlefield to run electronics," said Symko.
The scientist and his colleagues said they expect the technology could be used within two years as an alternative to photovoltaic cells for converting sunlight into electricity, as well as a way to cool laptop and other computers.
Five of Symko's doctoral students will present the research Friday in Salt Lake City during the annual meeting of the Acoustical Society of America.
Whatever happened to the acoustic refrigerator? I wish these guys the best of luck, but almost none of these energy related inventions ever make it to market.
This is a lot like thermoacoustics, which can take sound and convert it into waves of hot and cold bands — and can therefore be used as a refrigeration source.
You can do the opposite, use heat to generate the sound and use the sound to move a magnet through a coil to generate electricity.
The University of Pennsylvania has been working on this for years. There’s thermoacoustic refrigerators in use, and they were working on a self-contained machine for oil platforms to refrigerate natural gas (liquify it) by burning a small amount of it and using the heat to run a thermoacoustic generator which would provide cooling.
My daughter got a kit from the University and used it for a science fair project. It’s pretty cool, you just hook up a big 6-volt battery, it heats a small ceramic block in a tube, and you get a REALLY loud sound out of it, just from the standing heat/cold wave set up in the tube through the ceramic block (which is heated ONLY on one end).
I saw a rig that used solar power to heat the edge of the ceramic as well.
Kinda like nuclear power. Water is pumped in, heated and turned to steam, the steam powers the turbine that creates electric power.
Heat, making power.
Actually, 1% could be huge. It all depends on the temperature (quality) of the heat. If it can do 1% with a very low temperature differential, at low capital cost, it could be a real breakthrough.
I saw Laurie on the Fox Report Saturday late afternoon/early evening. She’s looking better than ever.
Internal combustion engines waste most of their energy as heat. If this works and can be adapted, perhaps a breakthrough here could improve a hybrid auto efficiency even further.
Kinda like when I first met my wife-to-be.
Al Gore will not be happy about this.
Just in time to save us from global warming. Turn all of that excess heat into electricity to power massive air conditioners to recool earth back down. Cool!
Did AlGore invent this too?
Your link points to a more complete article, which claims that it will be practical to recycle waste heat from a laptop computer into electrical power. That could certainly enhance the energy efficiency of a laptop. But I wouldn't hold my breath waiting to get more than 10% of my energy back that way . . .
But right behind is portability, economy, size/weight, and amount of power. A 40% efficient process that only produces 300 or 500 watts will help in many places for a short time, but can’t replace even a lightweight gas or diesel generator.
A “million dollar” “never-needs-refueling” marvel that can’t be used in the field or a building (like a Pu-power radioactive-fired satellite generator) isn’t practical either for a truck or remote station.
More likely, this first model will generate only a few watts. But it’s a start - future versions might have applications using the high-level heat from a gas turbine, smokestack, or steam piping.
Now, technically, it would AlexW’s wife (not Alex) I would want to see convert heat into electricity into food into orgasmisms.... Fergit the power plant, let’s see the application of that electricity into excited movement of the target body... 8<)
You’re ALWAYS going to have heat loss and irreversible processes in each conversion. The heat “lost” from the battery as the laptop runs is only a part of the battery’s energy from the stored electrical charge: further, this heat MUST be removed from the case (electronics) or they (literally) fry. This heat convertor-to-electricity also has losses itself, so it cannot turn all of the inbound heat to useful energy, which cannot in turn be turned back into the stored chemical battery energy.
So the net energy in the “outside-the-case” heat converter source is less than that inside the case in the chemical energy in the battery to begin with: and the net electrical/chemical energy available back into the laptop’s battery is less than what came out the first time.
The concept could extend the battery life a bit, but an heat outside source is required. Maybe we’ll be able to burn candles to run a laptop AND read the book? 8<)
Studies Improve Efficiency of Acoustic Conversion of Heat to Electricity
Here are summaries of the studies by Symko's doctoral students:
-- Student Bonnie McLaughlin showed it was possible to double the efficiency of converting heat into sound by optimizing the geometry and insulation of the acoustic resonator and by injecting heat directly into the hot heat exchanger.
She built cylindrical devices 1.5 inches long and a half-inch wide, and worked to improve how much heat was converted to sound rather than escaping. As little as a 90-degree Fahrenheit temperature difference between hot and cold heat exchangers produced sound. Some devices produced sound at 135 decibels -- as loud as a jackhammer.
-- Student Nick Webb showed that by pressurizing the air in a similar-sized resonator, it was able to produce more sound, and thus more electricity.
He also showed that by increasing air pressure, a smaller temperature difference between heat exchangers is needed for heat to begin converting into sound. That makes it practical to use the acoustic devices to cool laptop computers and other electronics that emit relatively small amounts of waste heat, Symko says.
-- Numerous heat-to-sound-to-electricity devices will be needed to harness solar power or to cool large, industrial sources of waste heat. Student Brenna Gillman learned how to get the devices -- mounted together to form an array -- to work together.
For an array to efficiently convert heat to sound and electricity, its individual devices must be "coupled" to produce the same frequency of sound and vibrate in sync.
Gillman used various metals to build supports to hold five of the devices at once. She found the devices could be synchronized if a support was made of a less dense metal such as aluminum and, more important, if the ratio of the support's weight to the array's total weight fell within a specific range. The devices could be synchronized even better if they were "coupled" when their sound waves interacted in an air cavity in the support.
-- Student Ivan Rodriguez used a different approach in building an acoustic device to convert heat to electricity. Instead of a cylinder, he built a resonator from a quarter-inch-diameter hollow steel tube bent to form a ring about 1.3 inches across.
In cylinder-shaped resonators, sound waves bounce against the ends of the cylinder. But when heat is applied to Rodriguez's ring-shaped resonator, sound waves keep circling through the device with nothing to reflect them.
Symko says the ring-shaped device is twice as efficient as cylindrical devices in converting heat into sound and electricity. That is because the pressure and speed of air in the ring-shaped device are always in sync, unlike in cylinder-shaped devices.
-- Student Myra Flitcroft designed a cylinder-shaped heat engine one-third the size of the other devices. It is less than half as wide as a penny, producing a much higher pitch than the other resonators. When heated, the device generated sound at 120 decibels -- the level produced by a siren or a rock concert.
"It's an extremely small thermoacoustic device -- one of the smallest built -- and it opens the way for producing them in an array," Symko says.
Now if we can only find a way to raise the Earths temperature a couple degrees ... /s