Originally posted by sonhouse
I think you could even use solar energy for the production of bacterial H2, needing only 80 degrees C, that is not a big stretch for solar energy, representing a concentration of less than ten to one, like ten square feet of solar collectors focused down to one square foot of vat, maybe even less, like 4 to 1 or 3 to 1. Any way you look at it, the energy input requirements are majorly less than making aluminum.

You may also be forgetting the cost constraints and energy needed currently to manufacture solar panels. They also have a very very low efficiency.

So you can heat 1 sq foot (let's make that ft^3) of vat with 10 sq ft of solar panel. You can maybe even heat a million gallons (133680 ft^3) with 1,336,800 sq ft (30.7 acres) of solar panel. But how much energy/day does that actually produce? And how much do those solar panels cost to make, in terms of both dollars and energy/electricity?

Originally posted by forkedknight
You may also be forgetting the cost constraints and energy needed currently to manufacture solar panels. They also have a very very low efficiency.

So you can heat 1 sq foot (let's make that ft^3) of vat with 10 sq ft of solar panel. You can maybe even heat a million gallons (133680 ft^3) with 1,336,800 sq ft (30.7 acres) of solar panel. But how mu ...[text shortened]... d how much do those solar panels cost to make, in terms of both dollars and energy/electricity?

In this case, we are not talking about photovoltaics, just concentrators, remember, all this process needs is heat, not electricity. So it can be a frame with aluminum foil or some such. There would have to be storage of heat to keep up that temperature for the bacteria during nighttime or storms and that would probably be more expensive than the collectors themselves. Still, everything added together would not be anything like the amount of energy it takes to make aluminum.

Originally posted by sonhouse
In this case, we are not talking about photovoltaics, just concentrators, remember, all this process needs is heat, not electricity. So it can be a frame with aluminum foil or some such. There would have to be storage of heat to keep up that temperature for the bacteria during nighttime or storms and that would probably be more expensive than the collectors ...[text shortened]... ything added together would not be anything like the amount of energy it takes to make aluminum.

That's a good point.

I still think, however, that the biggest problem with the bacteria farms would be scalability.

Originally posted by forkedknight
That's a good point.

I still think, however, that the biggest problem with the bacteria farms would be scalability.

Since it's 3 dimensional, as opposed to algae vats which are 2 dimensional essentially, bacteria can be scaled up from a real estate POV a lot faster than algae (or crops grown for oil). Bacteria vats, being like swimming pools with heaters, don't have to have access to the sun, they actually live in cracks in the rocks a mile or more underground so the sun is superflous for them, in our case we would maybe use the sun just to heat them up to their living temperature, so with well insulated tanks, they could stay hot all night long without even any input from the sun. On the Apollo moon missions, they had hot water onboard and no heater because the insulation was so good the water would stay hot for 6 weeks.

Originally posted by sonhouse
Since it's 3 dimensional, as opposed to algae vats which are 2 dimensional essentially, bacteria can be scaled up from a real estate POV a lot faster than algae (or crops grown for oil). Bacteria vats, being like swimming pools with heaters, don't have to have access to the sun, they actually live in cracks in the rocks a mile or more underground so the sun ...[text shortened]... onboard and no heater because the insulation was so good the water would stay hot for 6 weeks.

So you're going to use NASA quality thermal composites or ceramics for manufacturing fuels? Those kinds of materials are EXPENSIVE to produce. The main industries that use materials like that are scientific research, military, and sporting goods. Hardy anyone else uses them because they cost too much.

*edit* that, and space isn't exactly the most difficult environment for insulation. Open space itself is one of the best insulators known.

Originally posted by forkedknight
So you're going to use NASA quality thermal composites or ceramics for manufacturing fuels? Those kinds of materials are EXPENSIVE to produce. The main industries that use materials like that are scientific research, military, and sporting goods. Hardy anyone else uses them because they cost too much.

*edit* that, and space isn't exactly the most difficult environment for insulation. Open space itself is one of the best insulators known.

Not THAT big a deal, the Apollo ones were just big thermos bottles, vacuum inside like you said, great insulator, especially with IR reflectors on the inside of the outer wall which directs heat back inside and keeps it warm or cold that much longer. Anyway, it's just my musing about this, they don't need to keep it hot for weeks on end, only a day or so, which means it could be nothing more than a fiberglass insulated tank like a hot water tank in your house. They do a pretty darn good job of keeping the heat in. It wouldn't need anything fancy. I would think if they used solar, they would have backups anyway in case of storms and just cloudy weather. Some kind of electric heater that would kick in when solar went out too long for the insulation to keep it hot enough.
My guess is they would not even start with solar, but add that later so the primary heat would start out being electrical till proof of concept.
You could figure, why go to the trouble and expense of solar concentrators when they don't know for sure if it's going to work till they actually get a process going. Electric heaters, while not exactly green are cheap and reliable so it's one part of the equation that would keep things simple till the system is proven out.
BTW, space is a great insulator for CONDUCTION heat. It does nothing to stop IR, since IR is a short wavelength radio wave it propagates quite nicely through space, even though it follows the inverse square law of intensity. That's how they cool some space craft, put out radiators that dump IR into space and so cools of the insides, a workable solution but it takes a lot of surface area to make a significant BTU exchange.

Originally posted by sonhouse
And what a bacteria it is! It can't even reproduce unless the temperature is about 80 degrees C! but it digests cellulose and burps pure hydrogen gas!
http://www.sciencedaily.com/releases/2008/07/080707192643.htm

Not entirely a new story.

Originally posted by UzumakiAi
Not entirely a new story.

I'm all ear🙂 you have other link?