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US startup begins producing 40%-efficient thermophotovoltaic cells

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Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#41

Post by spoiler »

throwaway20304 wrote: post #34
fsh wrote: post #27

Earlier quoted context omitted.

There are betavoltaic generators [1] that directly produce electricity from decay electrons using p-n junctions (similar to photovoltaic cells). However, in the vast majority of applications, they get outperformed by modern lithium batteries (i.e. coin cells). [1] https://en.m.wikipedia.org/wiki/Betavoltaic_device

How can you compare a generator to a battery? How do you charge the battery without a generator?

A bettery, from the viewpoint of a circuit, is just another source. So we could call them chemical electricity generators, if we're brave enough to indulge the confusion

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#42

Post by johnvanommen »

TaylorAlexander wrote: post #15
fbnbr wrote: post #4

This just becomes interesting if electricity can be produced from reflected photons by the moon such as at night energy production is possible. Other than that I believe in fusion although the giant fusion reactor does help during the day. Instead of making photovoltaic more efficient they should do this with batteries

I believe we will build a functional net energy gain fusion reactor probably in the next decade if things go well (I’m rooting for SPARC), but we will still need to build an actual power plant (designed for long life, serviceability, improve efficiency based on what was learned before) and that will take a while. And then we need to build lots of them. And they will be very expensive. Probably fusion power will not b…

> (I’m rooting for SPARC)

Gives a whole new meaning to "Sun Microsystems"

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#43

Post by n6242 »

oefrha wrote: post #32
fbnbr wrote: post #4

This just becomes interesting if electricity can be produced from reflected photons by the moon such as at night energy production is possible. Other than that I believe in fusion although the giant fusion reactor does help during the day. Instead of making photovoltaic more efficient they should do this with batteries

Moonlight is ~1 mW/m^2, so good luck with that.

I was thinking you could cover the moon in rotating mirrors to redirect the light to solar panels. And if they can be controlled independently, you can tweak them and basically use the surface of the moon as a giant display, who wouldn't want the moon to look like a giant Apple logo?

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#44

Post by throwaway20304 »

spoiler wrote: post #41
throwaway20304 wrote: post #34

Earlier quoted context omitted.

How can you compare a generator to a battery? How do you charge the battery without a generator?

A bettery, from the viewpoint of a circuit, is just another source. So we could call them chemical electricity generators, if we're brave enough to indulge the confusion

I still don't quite understand it. Where does the battery get the energy? I understand that there's no difference in a circuit, but why is this comparison relevant? Many power sources are way less efficient that using a battery, but we need to charge the battery.

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#45

Post by pbmonster »

I don't get why they go for storage with this. Storing a block of carbon or tungsten at 2000°C for hours or days does not sound like something that will ever be economical. A battery leaking energy this quickly (and it will leak₎ will need to be incredibly cheap to ever make sense.

I wonder if you could use this with parabolic mirrors, though. Build a large mirror array, focus sunlight onto a big carbon sphere (maybe coat it with one of those new materials that are transparent for visible light but pretty reflective for IR), cover the top of the sphere in those new panels. They are more efficient than practically all solar cells and get much more power out the same area than solar cells. This should beat a photovoltaic parabolic mirror setup, right?

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#46

Post by 15457345234 »

londons_explore wrote: post #37

> emitter temperature of 2,400 C GE's combined cycle turbines can get system level efficiency of around 63% from these sorts of temperatures. (For those not familiar with them: They're basically aircraft jet engines followed by steam turbines using the hot exhaust. They are in widespread use to generate electricity from gas, but they can also run off any other liquid fuel, or simply off anything that gets very hot.)

There are a looooot of moving parts in a CCGT generating station, multiple oil loops, multiple coolant loops, many consumables, a complex control flow.

Being able to replace the combined turbine/alternator assembly with a 'when it gets hot, voltage comes out' unit would give you significant reliability gains and lower operating costs.

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#47

Post by dukeyukey »

throwaway20304 wrote: post #34
fsh wrote: post #27

Earlier quoted context omitted.

There are betavoltaic generators [1] that directly produce electricity from decay electrons using p-n junctions (similar to photovoltaic cells). However, in the vast majority of applications, they get outperformed by modern lithium batteries (i.e. coin cells). [1] https://en.m.wikipedia.org/wiki/Betavoltaic_device

How can you compare a generator to a battery? How do you charge the battery without a generator?

Betavoltaics aren't really either - they provide a constant, slowly-over-years declining flow of power. They can't be recharged, they _could_ be refueled (don't know if it's economic though), and are mostly used when you need a small flow of power and a long period of time between maintenance (think pacemakers, weather buoys, some satellites or probes).

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#48

Post by pbmonster »

londons_explore wrote: post #37

> emitter temperature of 2,400 C GE's combined cycle turbines can get system level efficiency of around 63% from these sorts of temperatures. (For those not familiar with them: They're basically aircraft jet engines followed by steam turbines using the hot exhaust. They are in widespread use to generate electricity from gas, but they can also run off any other liquid fuel, or simply off anything that gets very hot.)

They don't ever run those close to this hot, right? There's barely any turbine blade materials able to withstand half those temperatures.

At those temperatures, even the best alloys lose a large percentage of their strength. And also, steam this hot is incredibly corrosive.

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#49

Post by pbmonster »

15457345234 wrote: post #46
londons_explore wrote: post #37

> emitter temperature of 2,400 C GE's combined cycle turbines can get system level efficiency of around 63% from these sorts of temperatures. (For those not familiar with them: They're basically aircraft jet engines followed by steam turbines using the hot exhaust. They are in widespread use to generate electricity from gas, but they can also run off any other liquid fuel, or simply off anything that gets very hot.)

There are a looooot of moving parts in a CCGT generating station, multiple oil loops, multiple coolant loops, many consumables, a complex control flow. Being able to replace the combined turbine/alternator assembly with a 'when it gets hot, voltage comes out' unit would give you significant reliability gains and lower operating costs.

Well, you still have to cool those cells. It's still a heat engine, after all. And you can't just let radiation do the job for you, no way the semiconductor likes getting anywhere close to this hot.

Re: US startup begins producing 40%-efficient thermophotovoltaic cells

#50

Post by kgabis »

goodpoint wrote: post #31
svantana wrote: post #16

Could this be used to create a nuclear power generator without moving parts? Some radioactive material in the center, some coating to absorb the radiation, and a shell of these cells to generate electricity.

We already have a fusion reactor at a relatively safe distance called the sun.

We also have this thing called night, as well as weather and seasons.
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