Hacker Remix

Lightcell: An engine that uses light to make electricity

99 points by curl-up 4 days ago | 56 comments

DaniFong 3 minutes ago

[delayed]

corysama 35 minutes ago

A couple video interviews with the inventor:

https://www.youtube.com/watch?v=aMQYAqIxK1s

https://www.youtube.com/watch?v=1U_KbgF-sAc

bilbo-b-baggins 6 minutes ago

Reminds me of the TimeCube page…

DaniFong 2 minutes ago

[delayed]

nialv7 4 hours ago

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.

DaniFong 2 minutes ago

[delayed]

mppm 3 hours ago

1. The countercurrent heat exchanger achieves exactly that: exhaust gases are cooled while the inflowing fuel mixture is heated up.

2. Thermophotovoltaics in general can operate with any heat source, though this device is clearly optimized for combustion. However, the efficiency is far too low to compete in the large-scale power generation segment. This is almost certainly aimed at light aviation, heavy drones, military applications, etc., where there are not a lot of alternatives that combine small size, high power density and good efficiency.

EA-3167 3 hours ago

I suppose for aviation at least this is no less efficient than a gas turbine or a piston, and it's certainly a good deal quieter, has fewer moving parts, and requires less precision engineering than a jet engine. This feels tailor-made for attritable low->medium performance aviation, aka loitering munitions and drones. Strip away the "green" talk, and you're left with something that can burn just about anything (including hydrocarbons like avgas) without the complexity of a turbine.

cryptonector 2 hours ago

1. It's hard to capture all the waste heat. If you could run this indoors (but vent outdoors if the fuel is anything other than H2, naturally) then you could use some of the waste heat to heat a building.

2. There are thermovoltaic generators, but they're limited by the need to cool one side of the material. These are typically used in deep space probes that use Pu 240 to power them. To my knowledge thermovoltaic generation is not scalable or practical on Earth at this time.