4 ms·
>why this won't work, won't be useful, won't be cost effective, won't scale Not an expert, but reading this a few negatives popped out. Basically they are heat
by javajosh 5y ago
>why this won't work, won't be useful, won't be cost effective, won't scale
Not an expert, but reading this a few negatives popped out. Basically they are heating a black body to 2400C and then making electricity from gathering the emitted light in a cell. They get to pick a temperature to match the bandgap of the cell.
The key problem is getting something that hot without using another (lossy) form of power. The Sun's surface is ~5600C so that's enough headroom to get there from solar. That's cool. But are there any fission reactors that get (or could get) that ridiculously hot?
- giantg2 5y agoChernobyl did. I think most try to keep temperatures under 1000C. I think many FAST reactor designs are looking at 600C operating temps with peak temp reaching maybe 1200C during emergency testing. But my memory might be wrong.
- sandworm101 5y agoBiggest key problem imho is how they expect to store this heat energy. It looks like this cell will, like a PV cell, constantly be absorbing photons. If those photons aren't creating electricity/voltage across a gap then they are being converted into heat. So to keep the medium at temperature you would need to insulate it, to wrap it in a mirror, only exposing the flux to the energy-collecting cell as needed. That means moving parts. As for available temperatures from fission reactors: https://en.wikipedia.org/wiki/NERVA https://en.wikipedia.org/wiki/NERVA "When the reactor was operating at full power, about 1,140 MW, the chamber temperature was 2,272 K (2,000 °C)"
- thehappypm 5y agoThis is a bummer, but probably a reality. Perhaps some kind of LCD type tech could make for it to be more digital/less big metal moving around.
- Animats 5y ago"The team’s design can generate electricity from a heat source of between 1,900 to 2,400 degrees Celsius" That's way up there. That's well above the melting point of steel. That's above the highest temperature jet engines made for experimental aircraft.[1] Most jet engines try for exhaust gas temperatures around 600C or so, for a long useful life. Typical nuclear reactors, around 300C. It's not impossible to operate up at those temperatures. Every steel plant does it. There are ceramic and brick materials that can deal with such temperatures.[2] The storage medium would probably be some molten metal. This seems way too much trouble just to store energy. Now if this thing worked at 600C or so, there would be more uses. [1] https://www.nasa.gov/centers/dryden/pdf/88068main_H-1375.pdf https://www.nasa.gov/centers/dryden/pdf/88068main_H-1375.pdf [2] https://www.ceramicsrefractories.saint-gobain.com/refractory-solutions/steelmaking/steel-ladle https://www.ceramicsrefractories.saint-gobain.com/refractory...
- robotresearcher 5y agoThe article mentions the planned storage medium is insulated banks of graphite.
- javajosh 5y agoI'm a little unclear on the concept. You say storage medium, as if the graphite is expected to remain at very high temperature for an extended period. Preventing a chunk of super hot graphite from cooling is, if anything, an even larger engineering challenge than getting it that hot in the first place!
- thehappypm 5y agoI think they’re envisioning a no-moving-parts kind of system, which makes dealing with difficult environments easier.
- walnutclosefarm 5y agoNo, they claim no moving parts for the generator, but refer to engineering designs that use pumped liquid tin to move the heat within the system. Clearly the challenge there is building a pump that can handle liquid tin at 2400C.