alt Hacker NewsLightcell: An engine that uses light to make electricity
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A couple video interviews with the inventor:
Two questions I have:
1. How much of the fuel's energy is released as heat? They have a heat recapture device, but that's only used to preheat air/fuel, and not used to generate electricity. Is the energy in the heat simply discarded?
2. Can this be made to work without the process of burning? i.e. can it function purely from heat? If it can, it might be able to replace steam turbines in, for example, nuclear plants or CSP plants. That could be hugely beneficial.
Bottom line: 40% efficiency, which is better than I expected but the competition is batteries at 80+% efficiency. It's a hard sell, especially as continual improvements in battery storage will continue to eat away at their niche.
5,000 W/kg sounds great on paper compared to 150 W/kg for batteries and is even in the same ballpark as gasoline at 12,000 W/kg, but I think that's just the figure for the fuel. I don't think it includes storage, the solar panels, the burner, etc... The cost is an open ended question as well. Maybe this will pan out for aircraft?
I find the bandgap tuned cell interesting. It reminds me of a TPV https://www.nature.com/articles/s41586-022-04473-y which is tuned for infrared instead of yellow light.
My initial thought about this was that it's using fuel to make electricity, right? Rather than using sunlight/hydro/etc -- kinda like a generator, but without the mechanical aspect?
The energy densities listed are flagged as approximate, so grains of salt etc, but the numbers on the page aren't entirely consistent.
The stated energy density is "> 500 watthours/liter".
But higher on the page we see a relative-energy-density bar graph shows lightcell at 5x the energy density of lithium batteries, and (38/5 =) 7.6x less dense then petrol. This implies an energy density for lightcell of 1250 Wh/liter, as (according to Google) petrol clocks in just under 9500 Wh/liter, and (again according to Google) lithium batteries can reach 300 Wh/liter so let's call it 250 for the math to work out.
I'm curious which number is closer to truth: 500Wh/liter, or 1250? Is 1250 the theoretical max and 500 the current output in a test rig?
This seems possibly not crazy. If you can have one of these powered by natural gas and scale it to 20 kW then you have a nice home generator that is "whisper quiet" according to TFA and also: simple, easy to maintain, with few moving parts, perhaps even durable. The hydrogen aspect of this is not as interesting as the other fuels, though it'd be nice to know the efficiency numbers for different fuel types. That said, having to supply sodium might be a problem.
This burns fuel at very high temperature, and I wonder how they plan to deal with NOx production. They could attempt to burn the fuel in pure-ish oxygen (with an oxygen concentrator?), but that would increase the complexity of the design and compromise the "quiet" part.
I've periodically seen lightcell and danielle fong in various news / reddit /forums over the last few years and it always seems to be steeped in controversy.
I know next to nothing about the field / tech, but a portion of folks seem to be like "incredible visionary etc. etc." and the another portion like "fringe science / complete bullshit / this is as realistic as cold fusion" kind of thing.
Very interested to hear from folks more in the know of like, high level long term viability / what the implications are etc.
less moving parts means it could work in contexts where moving parts demand lubrication, maintenance.
I felt it was a bit light on putting the system energy efficiency/losses up front. I am sure they're stated but it was hard to work out how it compared to normal PV efficiency, or steam turbine efficiency.
Heat exchangers are applicable to lots of things. I am skeptical that this is significant because almost any heat energy process does reclaim and preheat, and so the size of the thermal mass and efficiency here would be exceptionally well studied and if they have made improvements, they may be as, or more valuable as IPR overall. So while it looks amazing, unless they are spinning it out into wider industry it will be a small increment over things in deployment.
Often I imagine storing light as fuel. Compared to hydrogen, it doesn't weigh much at all, and you can fit a lot in the same space.
(Yes, I know where the halfbakery is.)
This seems like a hydrogen fuel cell with extra steps.
Amazing idea. BTW, following Danielle on X, very insightful and bright minded person.
this was done by a company in Alberta,late 90's early 2000's, except burning diesel, same idea of tuned photovoltaics outside a quarts cylinder,where a flame was buring @ one specific coulor temperature, they were marketing an initial model for sailboats, and had working devices in service. published efficiencies wrre also 40%+ lost track of them and could not find again this effort uses excited sodium,though there will be a number of other possibilities
The solar panel conversion of sunlight to usable energy to around 20%, with a theoretical max of 30%. So it's better than that.
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Reminds me of the TimeCube page…