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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

#151

Post by WhyCause »

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.)

I worked for a power company that had something like this. Except it was two F4 Phantom jet engines (modified to use natural gas) per generator.

I believe there were two sets in that plant, and boy, did it get loud.

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

#152

Post by bluGill »

badtension wrote: post #141
bluGill wrote: post #134

Earlier quoted context omitted.

Many grids do have this for normal residences, but it only covers your air conditioner not everything (and maybe water heater). By running your AC on half duty cycle all day your house still stays cool enough and they are able to reduce substantial peak demand. For most people HVAC and water heating are the two biggest demands, and also ones where simple management can result in a substantial changes in demand withou…

Making thermostats that are aware of dynamic energy pricing or, better yet, are in part controlled by the energy company ( I want my house to be 21-24 C, I don't care when the cooling happens ) would give us massive flexibility. All power hungry devices should at least have that capability (maybe other than the kettle, lol). This is literally a cost of $20 hardware in many cases.

In most houses the HVAC and water heater are the only devices that the user can accept not being in full control. Everything else is like the kettle: when you turn it on you want it on now.

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

#153

Post by ed_balls »

megaman821 wrote: post #137
adrian_b wrote: post #124

Earlier quoted context omitted.

No, by using both a combustion-gas turbine and three steam turbines to recover the waste heat you get 63% efficiency for electrical energy production. By using the residual heat for hot water and for heating in winter and cooling in summer, the global efficiency typically becomes well above 80%. Even the best Diesel generators may reach around 55% efficiency, while working at much lower maximum temperatures. For a fe…

Different use cases. This is for taking intermittent electricity production and storing it as heat. It will mainly be used for industrial heat; the TPV electricity production adds a little extra utility to the system.

"SMRs are typically anticipated to have an electrical power output of less than 300 MWe (electric) or less than 1000 MWth (thermal)"

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

#154

Post by amluto »

pbmonster wrote: post #147
Tuna-Fish wrote: post #107

Earlier quoted context omitted.

No-one sane wants to do combustion in a pure oxygen environment. The solution isn't that, it's to eliminate nitrogen and replace it something else. Typically CO2, because you can get it for free and already preheated by recirculating exhaust.

Ok, so you recirculate exhaust into the combustion chamber and inject new fuel. Now what? It doesn't burn, since there is no oxidizer. The only way is to inject some. And since you don't want nitrogen, you can't inject air. So you inject pure oxygen, or something like peroxide? Sounds expensive.

There are multiple ways to separate air into a fraction with more oxygen and a fraction with less oxygen, on site, at reasonable scale. Pressure Swing Adsorption is a common one, found in most medical oxygen concentrators.

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

#155

Post by AtlasBarfed »

est31 wrote: post #126
AtlasBarfed wrote: post #115

Earlier quoted context omitted.

And of course carbon removal from burning the natural gas is totally out of the equation.

> And of course carbon removal from burning the natural gas is totally out of the equation. Sorry for being nitpicky, but burning natural gas does not remove carbon, it adds new CO2 to the atmosphere (if you release the burn products which is usually done). You probably mean that if you released that natural gas directly into the atmosphere instead, it would have a larger greenhouse effect than the CO2 released by th…

Ah, hacker news is out in force defending petroleum companies right to pollute the world.

As always to economics, if you can't measure it well, it doesn't exist!

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

#156

Post by philwelch »

est31 wrote: post #126
AtlasBarfed wrote: post #115

Earlier quoted context omitted.

And of course carbon removal from burning the natural gas is totally out of the equation.

> And of course carbon removal from burning the natural gas is totally out of the equation. Sorry for being nitpicky, but burning natural gas does not remove carbon, it adds new CO2 to the atmosphere (if you release the burn products which is usually done). You probably mean that if you released that natural gas directly into the atmosphere instead, it would have a larger greenhouse effect than the CO2 released by th…

> if you release the burn products which is usually done

It’s also possible to capture the CO2 rather than releasing it into the atmosphere.

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

#157

Post by _hypx_ »

mnw21cam wrote: post #21
RobLach wrote: post #6

Earlier quoted context omitted.

For those of us unfamiliar with the properties of these materials, what would be considered impressive? Are there examples that are better?

If you have a heat source with a temperature of 2500C, then the theoretical maximum efficiency of conversion is around 89% assuming you have a heat sink available that can stay below 30C. (1.0 - (30+273)/(2500+273) = 0.89). All heat engines will be worse than this because of practicalities, but a real steam turbine system can be around 47% efficient and a combined cycle can be 60% efficient, using a cooler "hot" end…

Which is the problem of the idea. Any kind of thermal engine, such as a stirling engine, would beat this idea in efficiency with those kinds of temperatures.

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

#158

Post by adrianN »

badtension wrote: post #146
adrianN wrote: post #145

Earlier quoted context omitted.

Shifting some load by a couple of hours is indeed often possible, shifting it by 12 hours is already difficult.

Interesting, I would have thought in many cases it is maybe not trivial, but easily doable at worst. Do you have some personal experience with that?

A friend is working at Siemens R&D on this topic.
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