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US startup begins producing 40%-efficient thermophotovoltaic cells

pv-magazine.com

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

#71

Post by zdragnar »

badtension wrote: post #64
awestroke wrote: post #51

Earlier quoted context omitted.

And we also have this looming thing called climate emergency, which should conceivably motivate us to forge ahead with renewables and adjust our energy usage patterns to match production peaks, lest we doom humanity to extinction

I feel like this is one of the biggest missed opportunities. Why do we insist on our energy system to be infinitely flexible and full power available 24/7? Is a habit of doing the laundry at night worth more than additional millions of tons of CO2 in the atmosphere? I understand convenience, laziness and inertia (resisting change) but I also think changing the times when we click "power on" is a simpler solution than…

You would have to retrofit every residence to handle daily brownouts (circuits for lights, furnaces and medical equipment stay on, everything else off).

You would have to completely rebuild most of the manufacturing industry, as many plants have startup times measured in hours or days.

It'd be cheaper to just build nuclear.

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

#72

Post by benj111 »

pbmonster wrote: post #48
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.

Afterburner?

That wouldn't impact blade temp.

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

#73

Post by fsh »

throwaway20304 wrote: post #44
spoiler wrote: post #41

Earlier quoted context omitted.

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.

Betavotaic generators usually produce extremely low power. A similarly sized battery can last for decades at the same power output.

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

#75

Post by adrianN »

leereeves wrote: post #63
pbmonster wrote: post #62

Earlier quoted context omitted.

If you shine solar radiation on a nice black carbon sphere, practically all of those photons are absorbed, right? The sphere gets hotter, and starts emitting IR photons. My idea was to now enclose this sphere in TPV modules - except in places where the parabolic mirror puts sunlight on it Let's say that's half of the sphere (but you could cut this number down if you chose a parabolic mirror with a long focal point).…

Wouldn't this process also contribute to climate change by trapping energy on Earth that would have been reflected back into space? Edit: Apparently, yes, current PV solar may also do this: > We found temperatures over a PV plant were regularly 3–4 °C warmer than wildlands at night https://www.nature.com/articles/srep35070 But I suspect/conjecture that turning sunlight directly into heat, then turning some of that he…

Making the earth’s surface darker contributes to climate change, yes (that’s why sea ice loss is particularly bad). When you use the sunlight to make electricity usually the net effect is still positive.

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

#76

Post by pjc50 »

leereeves wrote: post #63
pbmonster wrote: post #62

Earlier quoted context omitted.

If you shine solar radiation on a nice black carbon sphere, practically all of those photons are absorbed, right? The sphere gets hotter, and starts emitting IR photons. My idea was to now enclose this sphere in TPV modules - except in places where the parabolic mirror puts sunlight on it Let's say that's half of the sphere (but you could cut this number down if you chose a parabolic mirror with a long focal point).…

Wouldn't this process also contribute to climate change by trapping energy on Earth that would have been reflected back into space? Edit: Apparently, yes, current PV solar may also do this: > We found temperatures over a PV plant were regularly 3–4 °C warmer than wildlands at night https://www.nature.com/articles/srep35070 But I suspect/conjecture that turning sunlight directly into heat, then turning some of that he…

There is an "albedo effect", yes, but it's not cumulative while CO2 in the atmosphere is.

Arguably there should be a "white roof" campaign for urban areas, it would be a cheap way of reducing the urban heat island effect.

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

#77

Post by ChrisRR »

kgabis wrote: post #50
goodpoint wrote: post #31

Earlier quoted context omitted.

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.

I don't know why people always comment this on posts about renewables as if it's some kind of gotcha.

When there's no sun, then other countries probably have sun. When there's no sun, there's hydro. When there's no hydro there's wind. When there's no wind, there's tidal. When there's no tidal there's geothermal. And when there's none of those, there's stored energy in batteries.

And if for some reason all of those combined can't satisfy the demand, then there's nuclear as a last resort.

And if there's none of any of those at all, then we've probably got bigger problems anyway

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

#78

Post by pjc50 »

badtension wrote: post #64
awestroke wrote: post #51

Earlier quoted context omitted.

And we also have this looming thing called climate emergency, which should conceivably motivate us to forge ahead with renewables and adjust our energy usage patterns to match production peaks, lest we doom humanity to extinction

I feel like this is one of the biggest missed opportunities. Why do we insist on our energy system to be infinitely flexible and full power available 24/7? Is a habit of doing the laundry at night worth more than additional millions of tons of CO2 in the atmosphere? I understand convenience, laziness and inertia (resisting change) but I also think changing the times when we click "power on" is a simpler solution than…

Like computing, having high uptime has a value all its own compared to an unreliable system. Countries which do have regular brownouts you find people buying their own (inefficient, polluting) generators to get round it.

Smart demand-response may yet become a thing, but it's not yet a commodity product. You need a system to send out "turn off" notifications, and a system for measuring that in realtime, and a system for paying people. Some grids _do_ have this, but only for very large consumers.

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

#79

Post by labcomputer »

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.)

You have to do some “energy accounting” sleight of hand to get 63%, though. That number assumes that some of the low-grade waste heat can be used for, e.g., district heating. It’s also a peak steady-state number, only achievable under optimal load conditions.

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

#80

Post by awestroke »

zdragnar wrote: post #71
badtension wrote: post #64

Earlier quoted context omitted.

I feel like this is one of the biggest missed opportunities. Why do we insist on our energy system to be infinitely flexible and full power available 24/7? Is a habit of doing the laundry at night worth more than additional millions of tons of CO2 in the atmosphere? I understand convenience, laziness and inertia (resisting change) but I also think changing the times when we click "power on" is a simpler solution than…

You would have to retrofit every residence to handle daily brownouts (circuits for lights, furnaces and medical equipment stay on, everything else off). You would have to completely rebuild most of the manufacturing industry, as many plants have startup times measured in hours or days. It'd be cheaper to just build nuclear.

Industry uses most of the energy. The industry is already moving towards their own price optimizing energy usage and/or storage.
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