chrismb wrote:So let's just say it's 100% efficient (!!), there's gonna be this nano-'stuff' that can take on 20kW of power and it is a thousandth of a micron in thickness!?!? Anyone care to tell me something about thermodynamics here! How hot is this stuff gonna get?
If you have a 300 HP engine that is 75% efficient, it dumps 56kW heat. If you recover just the top 40% of that where the heat gradient is the highest, you're doing the easier part. If this stuff works at all, it probably works this well. Anything that can take a heat gradient and turn it into electrical output is going to have numbers similar to this. It's not the numbers that are shocking, it's the fact that anything can do this sort of energy recovery at all.
I'm gonna wait and see.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis
Thermocouples are thermoelectric devices. Most of the ones I am familiar with generate a few millivolts of voltage at essentially static-charge currents (microamps or less) for several dozen degrees of temperature difference (yep, there must be both cold and hot junctions!). That's nano-watts of power.
The article said their simulations indicated a 100-fold improvement in something, which I took to be power. We just went from nano-watts to tenths of microwatts, using the single thermocouple example.
You can gang up tens or hundreds of thermocouples to make practical thermoelectric devices. A thing the size of a small dorm refrigerator makes a few to a few dozen watts worth of refrigeration, at a low COP. A hundred times that efficiency is nice, but still around a KW in a device around 2 feet by 2 feet by 2 feet, weighing many pounds.
This might not be the earth-shaking breakthrough that it would at first glance seem. A very good improvement, yes. Not really world-changing, though.
A team of scientists from the Instituto Superior Tecnico in Lisbon, Imperial College London, and the Universities of St Andrews, Lancaster and Strathclyde as well as STFC’s Central Laser Facility staff have demonstrated the feasibility of a groundbreaking method called Raman amplification which can take long laser pulses and compress them to 1000 times shorter, but with intensities 300 times greater. This means that current very expensive and complex laser set-ups could eventually be replaced with smaller and more cost-effective systems. This would make many technologies, including methods used to develop x-rays which rely on lasers, far more accessible and easier to mass-produce. This latest development is another step in laser scientists’ quest to develop ever more powerful lasers, increasingly demanded by new technologies since the invention of the laser 50 years ago.
The technique has been examined over a two year period, using some of the world’s most powerful supercomputers, to test every possible aspect of the theory. "In the past, studies have been carried out to test the theory, but only using simplified models which do not include all of the relevant phenomena. Our new model has shown that, in most cases, the amplified laser beam breaks up into ‘spikes’, making it difficult to focus the beam to a small spot" said Dr Raoul Trines from STFC’s Central Laser Facility. "But for a few special cases, the amplified laser pulse is of excellent quality, enabling exceptionally tight focusing of the beam".
Professor John Collier, Director, STFC’s Central Laser Facility said; "This year’s celebration of 50 years of the laser* is a poignant reminder that we need to start thinking about the next generation of laser technology. We have come to rely on lasers so much in our daily lives, for everything from high speed internet connections to medical techniques, that we can’t afford to pause even for a moment in developing laser techniques further, because these new techniques take years to develop and test".
The next step is to apply the theoretical study on an actual high power laser and fine tune the method through rigorous experimental testing.
GW Johnson wrote:Thermocouples are thermoelectric devices. Most of the ones I am familiar with generate a few millivolts of voltage at essentially static-charge currents (microamps or less) for several dozen degrees of temperature difference (yep, there must be both cold and hot junctions!). That's nano-watts of power...The article said their simulations indicated a 100-fold improvement in something, which I took to be power. We just went from nano-watts to tenths of microwatts, using the single thermocouple example.
A thermocouple is intended to generate a voltage proportional to temperature while letting the least possible heat move through it. A thermoelectric generator is intended to move very large quantities of heat through it with no moving parts in the generator section, and making a fraction of that power available as electricity. No one uses a thermocouple to generate power. Efficiencies are commonly as high as 10%, which for what would be waste heat is pretty good, for a potentially cheap and low maintenance, high reliability generator. Even if it's 5% for cheap materials, it's a good bet.
What 5% or 10% efficiency times 100 fold means is not explained.
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!), there's gonna be this nano-'stuff' that can take on 20kW of power and it is a thousandth of a micron in thickness!?!? Anyone care to tell me something about thermodynamics here! How hot is this stuff gonna get?
!), there's gonna be this nano-'stuff' that can take on 20kW of power and it is a thousandth of a micron in thickness!?!? Anyone care to tell me something about thermodynamics here! How hot is this stuff gonna get?