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Old 10-29-2002, 04:13 PM   #1
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Default Thermator-a promising technology ?



G-diddy (at TIQ) had posted about this new device being developped in Iceland known as the Thermator. Like the Stirling engine, it generates electricity, using a heat differential ( and the thermoelectric effect).

http://news.bbc.co.uk/2/hi/science/nature/2352853.stm

What do you guys think of this technology ? Any comments on the efficiency claimed for this device ?

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Old 10-29-2002, 08:20 PM   #2
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It's nothing new, a thermoelectric generator... thermometers use the same concept.

The question is... what is its efficiency?
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Old 10-30-2002, 12:11 AM   #3
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Quote:
quote:Originally posted by Jnadke

It's nothing new, a thermoelectric generator... thermometers use the same concept.

The question is... what is its efficiency?
Hi Jnadke,

Yes of course you're quite right, the thermoelectric effect has been known and utilized for quite some time.

Here's the closest thing I can find to an efficiency rating :


As an example, a generator that gets 3 litres per minute (0.8GPM) of 75C (167F) hot water, gives about 50 Watts when also supplied with the same flow of cold water used for cooling.

Here's a link to a FAQ page from the company which makes the Thermator :

http://www.varmaraf.is/english/produ...thermatort.htm

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Old 10-30-2002, 12:36 AM   #4
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Alright, I found something that pertains a bit more to efficiency :

" What is the efficiency of Thermoelectric Generators?
The efficiency is about proportional to the temperature difference between the hot and cold fluids. With 70C difference the efficiency is about 3%."

So 3%...this is not a lot. And it wouldn't compare favourably with the Stirling, if it performs as Kamen is hoping it will. Then again, this 3% is assuming you have a hot waste water supply, so the energy would be essentially free. But I believe one of these generators costs about $1500, so it would take a long time to recoup this cost, under most circumstances.

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Old 10-30-2002, 05:11 PM   #5
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A purely electrical solution is favorable to a mechanical solution. Wherever you have moving parts you have efficiency loss. You also have the wear-and-tear factor.

Efficiencies of thermoelectric generators are a difficult thing to decide how to measure. Generally, how much waste heat is thrown at it versus the amount it actually converts to electrical energy.


The Stirling engine will seem favorable now, but as technology improves, thermoelectric generators will become more advanced. They will overtake it in efficiency. The thing is, once an item is embedded into our market it is difficult to replace it, much like the standard gasoline engine.
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Old 10-30-2002, 10:20 PM   #6
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Quote:
quote:Originally posted by Jnadke

A purely electrical solution is favorable to a mechanical solution. Wherever you have moving parts you have efficiency loss. You also have the wear-and-tear factor.

Efficiencies of thermoelectric generators are a difficult thing to decide how to measure. Generally, how much waste heat is thrown at it versus the amount it actually converts to electrical energy.

The Stirling engine will seem favorable now, but as technology improves, thermoelectric generators will become more advanced. They will overtake it in efficiency. The thing is, once an item is embedded into our market it is difficult to replace it, much like the standard gasoline engine.
(Some) Stirlings are already approaching the theoretical Carnot efficiency limit, and with innovators like Kamen pushing the issue, the limit is getting ever more approachable. I'm doubtful the Stirling will be overtaken in energy efficiency at any time in the near future.

In the meantime, check out another closely related technology to the above: http://www.powerchips.gi/press/pr_020924.shtml

NEW POWER TECHNOLOGY TO NEARLY DOUBLE AVAILABLE ENERGY IN AUTOMOBILES

Power Chips plc Gibraltar 24 September 2002

(Refers to: BOREF) NEW POWER TECHNOLOGY TO NEARLY DOUBLE AVAILABLE ENERGY IN AUTOMOBILES A new power generation technology could sharply increase the ability of a car's engine to convert fuel into useful power. By capturing waste heat energy and converting it into electricity, Power Chips plc, a majority owned subsidiary of Borealis Exploration Limited (BOREF) says it could increase an automobile engine's effective power output by 75%, significantly improving vehicle performance, efficiency and design flexibility.

Less than 15% of the energy in a gallon of gasoline reaches the wheels of a typical car; most of the rest is wasted as heat. Power Chips are designed to capture this wasted energy and convert it into electricity that can be used to power ancillary systems such as air-conditioning or entertainment.

By eliminating these secondary loads from the car's engine, all of the mechanical output can be directed into the drivetrain. This could allow auto manufacturers to design lighter, more fuel-efficient engines without sacrificing horsepower and torque. In new hybrid vehicles, the increased power could translate directly into improved acceleration and range for electric motors.

Power Chips are wafer-thin, fingernail-sized diodes that use quantum mechanical thermotunneling to generate electricity from heat. They are expected to have a wide range of applications and to produce electrical power more efficiently and less expensively than any existing technology.

By eliminating the drain on an internal combustion engine required to produce electricity, the engine's full power can be directed to the driveshaft. Automakers may thus be able to achieve the same horsepower and torque output with smaller, lighter, and more fuel-economical engines. And by using Power Chips to generate electricity, automotive manufacturers will be able to eliminate alternators and belts and obtain greater design flexibility.

This automotive application of Power Chips is described in a paper, "Automotive Waste Heat Recovery Using Power Chips", to be presented by Power Chips Dr. Brian Von Herzen on Thursday at the Global Powertrain Congress in Ann Arbor, Michigan. The conference is organized by the International Council of Powertrain Engineering and Management, and provides a forum for presenting new technologies and techniques to automotive engineers and management from around the world.

Since most of the energy consumed by an internal combustion engine is wasted, capturing much of that wasted energy can provide a large increase in energy efficiency. A typical engine producing 100 kilowatts of driveshaft power, for example, expels another 68 kilowatts of heat energy through the radiator and 136 kilowatts through the exhaust. The paper says that a panel of Power Chips against the radiator, if they reach their projected 70% of maximum possible efficiency, should generate 8.7 kilowatts, while Power Chips wrapped around the exhaust pipe could produce as much as 68 kilowatts.

"If Power Chips realize their potential," the paper concludes, "they will be able to replace the alternator, power all auxiliary loads electrically (including climate control), and add significant shaft power to an automobile with an electric-assist drivetrain -- perhaps a total electrical power which is fully 75% of the shaft power of the primary engine. The devices are designed to achieve this goal for less than $20 per kilowatt capacity, which is highly competitive with all alternator systems, but with no additional fuel cost for the energy generated."

The Power Chip is one of the first transformative technologies to emerge from the nanotechnology revolution. Power Chips are discs comprising two electrodes separated by a gap of less than 20 nanometers, through which the hottest (most energetic) electrons tunnel to create an electrical current. Power Chips are silent, nonpolluting, solid-state devices that are scalable as arrays to meet any size power load. They can generate electricity from heat produced by any primary energy source, including geothermal, coal, gasoline, natural gas, methane, and hydrogen.

They are projected to operate at 70% of the maximum theoretical efficiency for energy conversion, even when converting low-grade waste heat. The only other technology capable of converting such heat directly to electrical output is thermoelectric (Peltier) devices, but the efficiency of production thermoelectric systems is only 5-8%.

Power Chips are protected by an extensive patent portfolio covering general theory and specific techniques for quantum thermotunneling and thermal energy conversion. More details are available on the Power Chips plc Website http://www.powerchips.gi, including the full text of issued patents and photographs of prototype Power Chips.

Power Chips were invented and are being developed and licensed by Power Chips plc, a majority-owned subsidiary of Borealis Exploration Limited (BOREF). Both companies are incorporated in Gibraltar. Borealis business is reinventing the core technologies used by basic industries, including electrical power generation, cooling and thermal management, electric motors, and steel production.

Forward-looking Statement at http://www.powerchips.gi/fwdlook.shtml.
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Old 10-31-2002, 12:55 AM   #7
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Hi Don,

Powerchips sounds like a very promising technology ! As well, it sounds like the materials used to make Powerchips, would not be cost prohibitive. If this technology should come to fruition, one benefit of using it would be that it does not represent a technology which has to compete with the established auto manufacturing industry. Of course it wouldn't make the oil companies happy, as we would use less gas in our cars, but at the same time it wouldn't eliminate oil use altogether, so maybe it could coexist with traditional technologies.

Another good tech research company to keep tabs on.

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Old 10-31-2002, 01:52 PM   #8
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Quote:
quote:Originally posted by don c.
(Some) Stirlings are already approaching the theoretical Carnot efficiency limit, and with innovators like Kamen pushing the issue, the limit is getting ever more approachable. I'm doubtful the Stirling will be overtaken in energy efficiency at any time in the near future.
Do you have any data to back up this claim? If Stirlings were approaching this limit, it would be a major breakthrough. I think we'd be hearing about it more.

Much of the heat thrown at the Stirling is never really used by it... it's lost into the surroundings by convection/radiation. Unless they found a way to totally isolate the heat source from the surrounding air (by something that is completely unable to conduct heat), I doubt the Stirling will approach Carnot efficiency anytime soon. I'd also like the bearings that suffer no friction (Canot efficiency = usable power). Either that or they would have to make the Stirling spin at the speed of light, so that it would use up the energy before it can escape. Because these two facts are impossible, heat will always be lost by it.


The last I heard Stirling's are only capable of being, at maximum, 50% efficient. I could be wrong, though.
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Old 10-31-2002, 03:53 PM   #9
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Hi Jnadke,

I have heard this term 'carnot efficiency', and not being an engineer, I don't understand it fully. So basically this is the limit of the efficiency of any heat engine. This also means that it wouldn't apply fully to a device that works on the thermoelectric effect, is this true ? So then a thermelectric device could reach an efficiency higher than the carnot limit, but a Stirling engine couldn't.

As far as the limit of a Stirling engine, I have seen Stirling engine configurations before, where they were hooked up in tandem, so that the excess heat from one engine was contributed to the heat input of another Stirling engine. If this type of configuration works, then I suppose you could get much closer to the Carnot limit. But could the limit theoretically be exceeded with such a configuration ? I guess the Carnot principle is meant to be applied to an 'individual mechanical system'.

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Old 10-31-2002, 10:45 PM   #10
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The Carnot Cycle states that wherever a temperature differential exists, energy can be extracted. The Carnot efficiency is the general theorum for converting heat energy to energy capable of doing work. It works over a temperature differential (hot and cold side). The equation is:

Carnot efficiency = 1 - [T(cold) / T(hot)]

Obviously the larger the difference in temperature of the hot and cold side, the more efficient the engine can be. Stirling Engines don't work very well in "low-grade heat" (low temperature differential). Heat is the same energy used to perform work, just in a different form. The quest has always been on to master the conversion of heat to energy that we can currently use. The energy crisis has just sped it up.

Heat, however, likes to move from the hot side to the cold side on its own, by radiation. This is where it gradually spreads out until it heats up the cold side, and reaches equilibrium (same temperature). The Carnot Cycle tries to convert this heat to mechanical energy before this can happen.

Thermoelectric generators also follow the carnot cycle... they require a temperature differential to be present.
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