How To Do It...

It must be in here someplace....

https://en.wikipedia.org/wiki/Heat_transfer_physics

http://www.me.gatech.edu/files/nsf_onr_2012/keynote/Keynote%20Kaviany.pdf

http://journals.aps.org/prb/abstract/10.1103/PhysRevB.87.075317

Since phonons don't have charge and electrons do, I suspect you can't.

Electrons aren't converted to phonons either. Part of the energy of the electrons is converted to phonons (lattice vibration).

"A phonovoltaic (pV) cell converts vibrational (phonon) energy into a direct current much like the photovoltaic effect in a photovoltaic (PV) cell converts light (photon) into power. That is, it uses a p-n junction to separate the electrons and holes generated as valence electrons absorb optical phonons more energetic than the band gap, and then collects them in the metallic contacts for use in a circuit.^[1] The pV cell is an application of heat transfer physics^[2] and competes with other thermal energy harvesting devices like the thermoelectric generator."...

Maybe you could read this and gain a new perspective...

https://en.wikipedia.org/wiki/Phonovoltaic

I think this is the bottom line....

..."Therefore, Tuning the band gap and manipulating the symmetry of the first-row semiconductors (periodic table) is required to reach the first requirements of a pV cell (). The band gap in graphene has been tuned in a variety of ways. For instance, hydrogenated graphene (graphame for partial hydrogenation and graphane for full hydrogenation) can open a band gap ranging between 0 and 3.5 eV. At 24 hydrogen per 128 carbon, the band gap is tuned to the graphene-like optical phonon, with an energy around 200 meV.^[9] If hydrogenation did not significantly affect the electron-phonon or phonon-phonon coupling, this graphame composition could achieve 90% of the Carnot limit,^[10] much better than the best thermoelectric generator.^[11] However, hydrogenation is predicted to degrade the interband electron-phonon coupling substantially and proscribes its use in an efficient pV cell."

We need an engineered material...90% Carnot limit, wow....

That last sentence in the paragraph about doctoring graphene seems the most troublesome, and contraindicates progress.

Perhaps what I have been researching (home shop) is thermoelectric galvanic combination. I have yet to find a metal pair where the anode does not corrode at least to some extent, and dissimilar metal contacts seem necessary to produce a favorable potential on the output. The best device I fabricated had an output resistance of 3 Ω, about 1.5 V, in the range of 65-85 °C.

The device was actually outdoors in more or less full sunlight in West Texas in winter.

Incorporation of graphite into the matrix of the cell definitely helped with achieving a good warm-up of the cell, and may have lowered cell resistance, slightly.

Ok, I can buy phonons shaking loose electron-hole pairs from the junction not unlike doing the same with photons in a solar cell.

I know this might be a stupid question.

A. Are you trying to build or create some new type of device ?

B. Could you show us a picture of what your thoughts are in relation to phonones and electrons ?

I'm a touchy feely guy, I like to see something tangible.

In school, I often had a discourse with my math teacher in showing a visible demonstration for an equation, not just 1+2=, or (5*3)1.

I know that you have an unparalleled library of images.

I have been toying with designing a heat to electric conversion device with efficiency enough to make use of waste heat, for many years....The problem always comes down to maintaining an ideal bandgap through changing temperatures and conditions, as well as manufacturing methods that are simple and low cost.....A vacuum gap device with maintained structural integrity during expansion ie: maintaining gap width while expanding with high temperature tolerant materials, doesn't seem to be feasible, so another approach is needed....If a design that is tunable by wave characteristic that could be adjusted with external stimulation could be developed it might work....I had never heard of a phonon cell and am seeking to grasp the concept....

https://en.wikipedia.org/wiki/Thermoelectric_effect

http://news.mit.edu/2009/thermoelectric

https://www.quora.com/Reality-Check-Are-these-solid-state-heat-to-electricity-Power-Chips-plausible

When you speak of " heat to electric conversion " , this is what comes to mind.

I had a Coleman cooler, that would cool, not freeze cola, meat, veggies, etc.

It used a Thermo electric device that would convert electric energy to produce cold (12 V DC) if the input leads were reversed, it would produce heat. Thinking of that cooler, I wonder if heat were applied to the element, electric current would be produced ?

Yes these work, but are not efficient(5-8%) enough to be practical ....Thermoelectric generators(TEG)(also called a Seebeck generator) is a solid state device that converts heat (temperature differences) directly into electrical energy through a phenomenon called the Seebeck effect ..

https://en.wikipedia.org/wiki/Thermoelectric_materials#Device_efficiency

https://en.wikipedia.org/wiki/Thermoelectric_generator#Materials_for_TEG

https://en.wikipedia.org/wiki/Atomic_battery

Waste heat has a black body wavelength (energy) distribution whereas the phonoelectric effect works for only a narrow range of wavelength.

"While the thermoelectric generator converts heat, a broad spectrum of phonon and electron energy, to electricity, the pV cell converts only a narrow band of phonon energy, i.e., only the most energetic optical phonon modes. A narrow band of excited optical phonons has much less entropy than a similarly excited broad spectrum of phonons. Thus, the pV cell can exceed the thermoelectric efficiency. However, exciting and harvesting the optical phonon poses a challenge."

https://en.wikipedia.org/wiki/Phonovoltaic

So I'm thinking that while efficiency may be high for a narrow bandwidth of optical phonons, there will be a price to pay (energy) to convert junk heat to the low entropy refined phonons.

What about a feedback system? Looping the energy back in to the device as a power source to focus the energy into the phonon band? The energy is then harvested at a particular level....

I'm not sure how you would do that, but I still think that concentrating the energy spectrum would be reducing entropy and therefore cost more energy...

You might control the Seebeck effect a bit by somehow controlling the temperature differential. There's some interesting uses of this effect with Thermoelectric Fans.

Piezoelectrics seem pretty straight forward.

I thought in space no one could hear you scream...?

https://www.quora.com/Is-it-possible-to-convert-a-sound-wave-into-electricity

Sounds still transmit through solids (and liquids).

I think devices such as are being discussed will amount to a footnote or two, and that is about all.

Notwithstanding that, some of these solid-state galvanic cells I made still have voltage (and they seem to recharge themselves after draining off current using ambient to heat just lower than boiling water) after several years.

The idea was to have a cell that was not intrinsically galvanic (that would not run down quickly), that could power some form of communications devices, instruments, etc., and was rugged enough for very remote field deployment.

'..(that would not run down quickly), that could power some form of communications devices, instruments, etc.....'

Kind of like this?

.

Could you elaborate on your comment about certain technologies not amounting to more than a footnote or two?

I do not believe these technologies will compete with recent advances in battery technology. They are interesting nonetheless, and will retain their place in our history.

I think my "phonon cells" are pretty similar to dry pile cell, but with the exception that KCl is not the major ingredient in the phonon cell. We use other matrix ingredients to try and maximize current (supposedly from phonon coupling of energy to conductance bands from valence bands of adjacent crystals of other type, where the band energies are nearly or completely resonant.

The cells I made still have corrosion taking place, and are therefore primarily galvanic, and although pretty rugged, are also shock sensitive (stop working).