5 ms·
The reaction consumes water, which isn't exactly abundant on a space station or space vessel. You can regain the water by burning the alcohol, which can be done
by oxymoron 10y ago
The reaction consumes water, which isn't exactly abundant on a space station or space vessel. You can regain the water by burning the alcohol, which can be done in a combustion chamber without reintroducing the CO2 to the air of the habitat. That's a rather exothermic reaction – and I'm guessing that the bionic leaf also generates excess heat – which might be a problem. Space vessels can only cool down by radiating heat, which I gather to be a quite complex problem. Nevertheless, it might be workable for all I know...
- choosername 10y agoWhy can't the heat be converted to electricity?
- heeen2 10y agoI think you need a temperature gradient to generate electricity from heat
- siculars 10y agoThe space station is in, uh, space. I'm fairly certain a temperature gradient could be arranged.
- seer 10y agoIt's actually the complete opposite - space is not "infinitely cold" it's more like "infinitely isolating" - like the perfect giant thermos. Space suits for example have a whole layer of water tubes just to cool down the astronaught, otherwise they will pass out from their own body's temperature.
- naasking 10y agoIndeed, black body radiation isn't very effective at dissipating heat!
- creshal 10y agoThe ISS has an 28 tons active cooling system that barely radiates away as much heat as a one ton HVAC unit on Earth (70kW). It's hard to generate a temperature gradient when you're blasted from the unfiltered Sun on one side, and reflected IR from Earth.
- deelowe 10y agoAnd surrounded by a near vacuum.
- deelowe 10y agoAnd yet thermos has somehow made billions by assuming the opposite.
- oxymoron 10y agoSome of it probably could be, but the effiency of those processes are low enough that you'd still have a heat problem. Also, recall that the energy originated with the solar panels to start with. It's a very wasteful way of generating electricity compared to the solar panels, so although it might be worth considering to recover some of the energy investment and eliminate a fraction of the heat, the net output of such a process will probably be an order of magnitude lower than the initial energy investment.
- codewiz 10y agoBecause heat is pure entropy; it's what you ultimately end up with after electricity has been used to do work, and the process is irreversible due to the Second Law of Thermodynamics: https://en.wikipedia.org/wiki/Second_law_of_thermodynamics#General_significance_of_the_law https://en.wikipedia.org/wiki/Second_law_of_thermodynamics#G... Only a difference in heat levels can still be converted to electricity, for instance by reverse Peltier effect: https://en.wikipedia.org/wiki/Thermoelectric_cooling https://en.wikipedia.org/wiki/Thermoelectric_cooling
- deleted 10y ago[deleted]
- creshal 10y agoAnd on a space station, most of your heat differential is created by active cooling, so recovering that via Peltier elements is a bit… counter productive.
- choosername 10y agoThe Second Law of Thermodynamics just means the conversion can't be a hundred percent efficient. Indeed, I didn't think of that as a problem.
- taneq 10y agoYou're overcomplicating this hugely. It's much simpler to burn the alcohol within the astronauts, converting it to a small amount of heat, CO2 and happiness.
- jcoffland 10y agoI don't think they will enjoy drinking isopropanol or isobutanol.
- paavokoya 10y agoCan confirm, have drunken ethanol before.. the after effects are devastating
- tarikjn 10y agoPlease tell us more...!
- goldenkey 10y agoYou missed the key distinction here, ethanol is not the greatest substance, but is relatively safe for animals. Other side chain alcohols metabolize into byproducts like formaldehyde and well, are highly toxic. This whole distinction is the basis for the sale of "denatured alcohol" / "wood alcohol" and its much cheaper price. "In some countries, sales of alcoholic beverages are heavily taxed. In order to avoid paying beverage taxes on alcohol that is not meant to be consumed, the alcohol must be "denatured", or treated with added chemicals to make it unpalatable." [1] https://en.wikipedia.org/wiki/Denatured_alcohol https://en.wikipedia.org/wiki/Denatured_alcohol I assure you, the after effects of drinking most alcohols are much more devastating than your average spirit. For reference: ethanol (Grain alcohol) rat, oral 7,060 mg/kg isopropanol rat, oral 3,600 mg/kg isobutanol rat, oral 2,460 mg/kg Hardy harr harr harr...
- alex_hitchins 10y agoCan it not lead to blindness?