A "new" way to capture energy

[KeithPickering]

There have been some exciting developments recently in thermoelectric materials (that is, materials that generate electricity when heated).

First, from CalTech, a silicon nanomesh. Reading the figures of the paper, it would seem that the nanomesh in the first lab experiments has acheived a rather high ZT value of ~1.2 (whereas the best off-the-shelf material has a ZT of about 1). ZT is a figure-of-merit for thermoelectric materials which is based on the ratio of electrical conductivity to thermal conductivity.

Even better, scientists at the University Arizona report a quantum engineering breakthrough that could achieve ZT’s of 50 or higher, using simple (and cheap) polymerized benzene.

Although these breakthroughs (especially the quantum one) may be very, VERY huge, the application for FF is also beneficial. Specifically, the proposed method for capturing the energy from x-rays released in the FF reaction has been photoelectric. With super efficient thermoelectric materials, it might be simpler and cheaper to simply absorb the x-rays (with lead, for example) and convert the resulting heat energy into electricity.

[tcg]

This is a fascinating subject, not only for harvesting power from the DPF production of X-rays, but also as a method to get a few extra watts cheaply from the waste heat that the device will produce. If it works, the method should scale down economically to any source of heat.

As an electrician, I can suggest another application right away. Having installed several sets of solar panels, I learned from experience not to touch them when they have been exposed to the sun for a while. The natural heat build up is a source of hazard and inefficiency. When the panels are hot, they yield less watts per lumen. Extracting the heat to generate electricity would increase the efficiency of the panels, a double win.

Doncha love modern technology?

[Rezwan]

KeithPickering wrote:
Even better, scientists at the University Arizona report a quantum engineering breakthrough that could achieve ZT’s of 50 or higher, using simple (and cheap) polymerized benzene.

tcg wrote: Having installed several sets of solar panels, I learned from experience not to touch them when they have been exposed to the sun for a while. The natural heat build up is a source of hazard and inefficiency. When the panels are hot, they yield less watts per lumen. Extracting the heat to generate electricity would increase the efficiency of the panels, a double win.

Do the math for the electrical laymen here. A double win, or 50 times win? With “ZT’s of 50”, How much more efficient/ how much greater output could a solar panel yield?

Is this the breakthrough solar has been waiting for? No need for carbon taxes?

[tcg]

My original choice of words was “win/win”, but it is an expression somewhat overused. I could not possibly quantify the gain since the technology is not yet mature. My experience was that a momentary contact with the panel produced second degree burns to the side of my hand. If any inexpensive means could be developed to harvest some electricity from this heat, it would be a good thing and worth keeping track of its development.

[Brian H]

KeithPickering wrote:
…

Even better, scientists at the University Arizona report a quantum engineering breakthrough that could achieve ZT’s of 50 or higher, using simple (and cheap) polymerized benzene.

Although these breakthroughs (especially the quantum one) may be very, VERY huge, the application for FF is also beneficial. Specifically, the proposed method for capturing the energy from x-rays released in the FF reaction has been photoelectric. With super efficient thermoelectric materials, it might be simpler and cheaper to simply absorb the x-rays (with lead, for example) and convert the resulting heat energy into electricity.

That’s incredible. There are heat gradients d*** near everywhere to exploit. The coating is a micron thick; it could be used directly in the FF reactor to cool the electrodes, too, BTW! This could jump the Q of the FF system by an order of magnitude (since all the recovered/converted heat would be added to the “profit” portion of the equation). It also might take the lid off the cycling speed, and allow the system to run at 10X the Hz, at 10X the power, etc.! Not only a base power of 50MW, but a huge jump of the Q on top of it?!? We could be talking 100s of MW from a FoFu here!

But efficiencies everywhere would jump. Coat a car engine with it, put it onto computer chips to cool them, etc., etc.

“This changes everything”!!

[Aeronaut]

Sorry, Brian. The basic cycling speed is going to be limited by the basic design parameter of the critical speed, which translates directly into length of the axial phase. Since we won’t be able to appreciably shorten the electrodes in this timeframe, I’d be looking for ~1khz PRF.

Are you sure it’s going to stand up to X-ray bombardment in the anode? If yes, will it be installed below the skin effect depth?

Other than those questions, there are a lot of parts like the pumps, vacuum housing, and caps that can be partially powered this way. I saw an ad in Green Manufacturing (?) magazine last week for an industrial air compressor which, under certain circumstances, could recover 100% of the electrical input as compressed air and heat. I’ll give them more like 80% to 95%. The ingenuity came from using the waste heat to make hot water.

Whodathunk? 😆

[Brian H]

IIRC, Eric was talking about Hz on the order of 1500+ or so initially, with 25MW output — limited by cooling efficiency, not anode length. Electrode cooling with a micron-thick layer should be fairly trivial to engineer, IMO. The coating can be made of just about any molecule/material that can be structured into a ‘forest’ of vertical chains, so X-ray transparency should also be easy enough to manage. And every bit of recovered heat adds to the ‘profit’, so I am sure Q can be hugely increased.

[Aeronaut]

Brian H wrote: IIRC, Eric was talking about Hz on the order of 1500+ or so initially, with 25MW output — limited by cooling efficiency, not anode length. Electrode cooling with a micron-thick layer should be fairly trivial to engineer, IMO. The coating can be made of just about any molecule/material that can be structured into a ‘forest’ of vertical chains, so X-ray transparency should also be easy enough to manage. And every bit of recovered heat adds to the ‘profit’, so I am sure Q can be hugely increased.

Yes, the patent referred to 1khz, in the context of upper cooling limit perception at that time. The real engineering feat in the onion is to support, cool, and wire the whole contraption for a stream of pulses over 1MW each. I suspect your cooling proposal may have a similar wiring challenge.

[Brian H]

Aeronaut wrote:
…

Yes, the patent referred to 1khz, in the context of upper cooling limit perception at that time. The real engineering feat in the onion is to support, cool, and wire the whole contraption for a stream of pulses over 1MW each. I suspect your cooling proposal may have a similar wiring challenge.

Well, it’s easier to control current than heat! 🙂

[Aeronaut]

Brian H wrote:

…

Yes, the patent referred to 1khz, in the context of upper cooling limit perception at that time. The real engineering feat in the onion is to support, cool, and wire the whole contraption for a stream of pulses over 1MW each. I suspect your cooling proposal may have a similar wiring challenge.

Well, it’s easier to control current than heat! 🙂

I’d rather sell electric output than thermal. Don’t forget to coat the wiring, too. 😉

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