3 ms·

FTA: “The potential downside is that this system requires energy to release the water – the base of the device needs to reach 184 °C (363 °F) to wring it out. B

FTA: “The potential downside is that this system requires energy to release the water – the base of the device needs to reach 184 °C (363 °F) to wring it out. But the team says the device can tap into waste energy or heat from other systems, like buildings or vehicles.” I guess it’s fairly hard to get 184°C of heat out of buildings. Getting it out of ICE vehicles is easier, but the device will add weight to the vehicle, and those are on the way out (slowly). So, that leaves getting it out of waste energy such as excess solar or wind energy. If that’s your heat source, an important metric is “how many Watt hours per liter” I skimmed the paper. AFAICT, it only mentions usage of current state of the art devices, at 11 to 23 kWh/l, compared to 5 to 7 kWh/l for conventional passive systems. What did I overlook?

sandworm101 2y ago
Getting 184c out of a typical car engine won't be easy. You might use exhaust gas but that would be difficult to regulate and seems wasteful. But if you have a car engine then you have a fuel source. Getting 184c out of a gasoline flame is dead simple.
bee_rider 2y ago
What humidity levels do the conventional passive systems work at? In regions where there’s excess solar energy and insufficient humidity, the tradeoff seems maybe worth it? Excess solar energy brings to mind stuff like putting it through solar panels, which can be limiting. But if we just need to convert photons to phonons, no need to stop by in electron-vill, a big dumb array of mirrors could do it, right?
- datameta 2y ago
  Yeah, no need to do sunlight->electricity->thermal as mirrors would be much more efficient.
datameta 2y ago
Hmm, desert sand can typically reach 150-200F, so there's a start.
- nomel 2y ago
  And a couple of mirrors can double it.
rs999gti 2y ago
> The potential downside is that this system requires energy to release the water Damn you physics!

sandworm101 2y ago

Getting 184c out of a typical car engine won't be easy. You might use exhaust gas but that would be difficult to regulate and seems wasteful. But if you have a car engine then you have a fuel source. Getting 184c out of a gasoline flame is dead simple.

bee_rider 2y ago

What humidity levels do the conventional passive systems work at? In regions where there’s excess solar energy and insufficient humidity, the tradeoff seems maybe worth it? Excess solar energy brings to mind stuff like putting it through solar panels, which can be limiting. But if we just need to convert photons to phonons, no need to stop by in electron-vill, a big dumb array of mirrors could do it, right?

datameta 2y ago
Yeah, no need to do sunlight->electricity->thermal as mirrors would be much more efficient.

datameta 2y ago

Hmm, desert sand can typically reach 150-200F, so there's a start.

nomel 2y ago
And a couple of mirrors can double it.

rs999gti 2y ago

> The potential downside is that this system requires energy to release the water Damn you physics!