cool clear water

[vaskidmark]

https://www.youtube.com/watch?v=jFBHc2qafgU

Dean Kamen & Coca Cola make it available.  http://www.popsci.com/article/science/pure-genius-how-dean-kamens-invention-could-bring-clean-water-millions?dom=PSC&loc=slider&lnk=1&con=pure-genius

Stuff it in a corner of a conex box that serves as the local bodega.  Give away the water - as much as you want.

Using a process called vapor compression distillation, a single Slingshot can purify more than 250,000 liters of water per year, enough to satisfy the needs of about 300 people. And it can do so with any water source—sewage, seawater, chemical waste—no matter how dirty.

Talk about being a game changer.

stay safe.

[Ron]

Very cool!

[Jamisjockey]

Evil corporations!

[RevDisk]

Dean Kamen is friggin awesome. His medical devices have helped a lot of folks.

That design of his is very simple and very good. The "no consumables" part is best. The Stirling engine can be powered by basically anything that burns, or one could just use standard electricity.

Thing is, this can scale down. Or up. Only part that kinda sucks is it needs a decent amount of startup power. Be very awesome for a vacation cabin or whatnot. Assuming you had access to a water source (creek, rain barrels, etc), you could use this to filter instead of installing a well or elaborate filtration system.

Has some interesting military potential too. Not something most soldiers think about, but supplying water to field units is a big deal.

[AJ Dual]

Dean Kamen is friggin awesome. His medical devices have helped a lot of folks.

That design of his is very simple and very good. The "no consumables" part is best. The Stirling engine can be powered by basically anything that burns, or one could just use standard electricity.

Thing is, this can scale down. Or up. Only part that kinda sucks is it needs a decent amount of startup power. Be very awesome for a vacation cabin or whatnot. Assuming you had access to a water source (creek, rain barrels, etc), you could use this to filter instead of installing a well or elaborate filtration system.

Has some interesting military potential too. Not something most soldiers think about, but supplying water to field units is a big deal.

I became aware of that when I learned there was even a project to collect the water from HMMV diesel exhaust. 

[Brad Johnson]

I like the concept, but I think they're grossly under-emphasizing the energy needs for the unit.  It takes X amount of energy to gassify a specific volume of water at a specific pressure. That's straight physics and no miracle invention will change it. Looks like what they've accomplished is ramping up efficiency a significant amount, a feat impressive in it's own right.  I wonder how well the efficiency increases will scale.

Brad

[RevDisk]

I like the concept, but I think they're grossly under-emphasizing the energy needs for the unit.  It takes X amount of energy to gassify a specific volume of water at a specific pressure. That's straight physics and no miracle invention will change it. Looks like what they've accomplished is ramping up efficiency a significant amount, a feat impressive in it's own right.  I wonder how well the efficiency increases will scale.

Brad

The claim is 10 gallons of water per KWh.

They're basically trying to optimize the amount of heat they reuse, by transferring to the incoming grey water. Bet $5 that the hippies start screaming that the discharge grey water is concentrating contaminants and a source of heat pollution.

Here's the patent with all the technical details:

https://www.google.com/patents/US20140034475

[AJ Dual]

Every unit comes with an AK47 to shoot hippies.

Problem solved.

[SADShooter]

Every unit comes with an AK47 to shoot hippies.

Problem solved.

Throw in a Soylent processor and you're in really good shape until/unless the hippie supply runs out...

[RevDisk]

Military HMMWVs use 24V and 100A or 200A alternators. Assuming you could tap half of that, you have 1200 to 2400 KW.  So that's theoretically 10 to 20 gallons per hour. M149 Water Buffalo is 400 gallons. It'd take 20 hours to fill, which isn't ideal, but for stationary ops, 20 gallons drainage per hour isn't atypical. Fill at beginning of op, top off when possible. Hit a water point if you drop too fast or need a quick refill.

Be very handy for lengthy field ops, FOBs, disaster management, etc.

Hell, I would have loved something like that. Often, we had to have baby wipe showers instead of field showers (pallet plus water bag) because we couldn't send the HMMWV or LMTV back to a water point. Under most exercise and damn near all hostile fire zone rules, you can't just send one vehicle anywhere. You have to travel in at a minimum a two or three vehicle convoy. I'm not saying it'd necessarily be fuel neutral, but the overall fuel cost wouldn't be as bad as first glance because you'd need less supply convoy movement.

[cordex]

A few cents per gallon in electrical isn't bad for on-grid costs.

If it could be done efficiently, I'd love to see a smaller version designed for a single household.  Maybe even an off-grid option.  You probably could reduce input power if you preheated the source water by storing it the sun in a black container to get some passive solar heating.

[KD5NRH]

The claim is 10 gallons of water per KWh.

How much of that energy input is purely heat, though?  A heat exchanger on a vehicle or generator exhaust can net a ton of heat for no more additional power input than a tiny pump.  Even if it's not hot enough, a nearly free preheat is a good way to cut energy requirements.

[RevDisk]

How much of that energy input is purely heat, though?  A heat exchanger on a vehicle or generator exhaust can net a ton of heat for no more additional power input than a tiny pump.  Even if it's not hot enough, a nearly free preheat is a good way to cut energy requirements.

Ehhhhh, IMHO, not the extra engineering/plumbing costs. A lot less flexibility in exchange for a bit more efficiency.

Fine for permanent structures. I could see plumbing in a line from a chimney or cooking heat source. But mobile? Oh hell no. Maybe in an RV.

[AJ Dual]

Hmm... If they pumped the initial water boiling chamber to a partial vacuum, wouldn't that reduce the required heat input drastically? It could even boil just at ambient temperature if the pressure was low enough.

Just a WAG, since I don't know the physics or engineering to calculate it, but I'd bet the energy input to run a vacuum pump is less than the energy input to boil the water at 14psi/1bar. I guess you'd need some clever way of transporting the produced water vapor back into full atmospheric pressure so you don't have the power or extra parts of a refrigerated condenser, and an engineering study to see if the seals, valves and pumps needed for such an operation are less efficient, or somehow require a larger logistical tail than the boiler/heat exchanger of the Kamen design.

I will further guess that if the benefits of adding vacuum to the the Kamen/Dekka design were actually realizable in practice, they'd have done it. But still a nice thought.

[KD5NRH]

Ehhhhh, IMHO, not the extra engineering/plumbing costs. A lot less flexibility in exchange for a bit more efficiency.
Fine for permanent structures. I could see plumbing in a line from a chimney or cooking heat source. But mobile? Oh hell no. Maybe in an RV.

I was thinking in terms of the bodega setup or other more-or-less fixed location system, or a system that is fixed to the vehicle.  Mount it to a combination water buffalo and generator, for example.  Then you could even post-heat the same way for hot showers and have the shower drain pull the water right back in to be recycled again - only fuel costs (and a bit of evaporation loss if your showers are too open) to take as long of a shower as you want. 

I bet with a little creativity someone could build a complete field shower with hot water and lights into a shipping container; generator and the Slingshot(s) at one end, showers down both sides with a fibergrate floor, subfloor sloped to a sump at the Slingshot input and flat tanks overhead to gravity feed the showerheads.  To prefill, just dump dirty water on the floor (All right men, everybody go pee in the shower!) or put clean water in the tanks.  PV on top if you want to reduce load on the generator and you should be able to get the day to day use cost pretty low.  Now that I think about it, with the relatively well sealed container, evaporative loss would probably be more than offset by folks peeing in the shower.  Add power and water outputs and/or a rollout canopy over some urinals (No point wasting power to have flush toilets...or is there?  Dehydrating the poo might be worth the extra fuel cost in sensitive environments, situations where power is abundant, or just in situations where septic capacity is limited.) and you've got a pretty nice multifunction haulable latrine.

[Regolith]

Hmm... If they pumped the initial water boiling chamber to a partial vacuum, wouldn't that reduce the required heat input drastically? It could even boil just at ambient temperature if the pressure was low enough.

Just a WAG, since I don't know the physics or engineering to calculate it, but I'd bet the energy input to run a vacuum pump is less than the energy input to boil the water at 14psi/1bar. I guess you'd need some clever way of transporting the produced water vapor back into full atmospheric pressure so you don't have the power or extra parts of a refrigerated condenser, and an engineering study to see if the seals, valves and pumps needed for such an operation are less efficient, or somehow require a larger logistical tail than the boiler/heat exchanger of the Kamen design.

I will further guess that if the benefits of adding vacuum to the the Kamen/Dekka design were actually realizable in practice, they'd have done it. But still a nice thought.

You need to hit the right temperature to kill microorganisms, though. If you boil the water at a lesser temperature, you may not kill everything.

[KD5NRH]

You need to hit the right temperature to kill microorganisms, though. If you boil the water at a lesser temperature, you may not kill everything.

Distilling should leave them behind...though sterilizing the waste would still be a very good idea.  I wonder how much of the solids left behind from the distillation would be sufficiently flammable to make practical fuel.

[Ron]

This thread makes me want a still suit 

[dogmush]

Hmm... If they pumped the initial water boiling chamber to a partial vacuum, wouldn't that reduce the required heat input drastically? It could even boil just at ambient temperature if the pressure was low enough.

Just a WAG, since I don't know the physics or engineering to calculate it, but I'd bet the energy input to run a vacuum pump is less than the energy input to boil the water at 14psi/1bar. I guess you'd need some clever way of transporting the produced water vapor back into full atmospheric pressure so you don't have the power or extra parts of a refrigerated condenser, and an engineering study to see if the seals, valves and pumps needed for such an operation are less efficient, or somehow require a larger logistical tail than the boiler/heat exchanger of the Kamen design.

I will further guess that if the benefits of adding vacuum to the the Kamen/Dekka design were actually realizable in practice, they'd have done it. But still a nice thought.

Yes.  That's how they do it with salt water purifiers on large ships.

Pump a vacuum, boil salt water, condense it on a cold water coil, run it through a UV sterilizer (at least on the models I'm familiar with) and ta-da.  The Maxim evaporators we use on Army watercraft use waste heat from the engines (they pump engine coolant through the "hot" coil) and sea water to cool the steam.  A Venturi type eductor placed in one of the water pipes supplies the vacuum so the only thing that actually needs electricity to run is the three pumps (distillate, brine (grey water) and raw water) and the UV sterilizer.  They are way more efficient in terms of power to water produced then the old RO's were.  They do however take a skilled operator, as things like water flow and vacuum have to be adjusted as temperatures (engine and seawater) change, and they lose a bunch of efficiency as the sea water gets warmer.

[erictank]

Throw in a Soylent processor and you're in really good shape until/unless the hippie supply runs out...

Unpossible. Everyone knows there's an inexhaustible supply of hippies.

Now, you may have to follow the herd as you hunt out the area you're in...

[Headless Thompson Gunner]

10 gallons per kWh seems incredibly efficient. 

A small gas generator gets something like 5 kWh from a gallon of fuel.  That would net you 50 gallons of drinking water.

[KD5NRH]

10 gallons per kWh seems incredibly efficient.

And an excellent reason to plan fixed and/or trailer installations around multiple or scaled-up units.

[birdman]

10 gallons per kWh seems incredibly efficient. 

A small gas generator gets something like 5 kWh from a gallon of fuel.  That would net you 50 gallons of drinking water.

It is.  Its a good idea, and an elegant solution (highest praise from an engineer).  Basically, rather than having to obtain the full 2 kWH/gallon that straight boiling would take, the counter flow HX reduces that by nearly 50x, and the rest of the power usage is the compressor.
Kudos dean, kudos.

[K Frame]

Oh holy crap!

Those bastards are creating highly concentrated toxic waste!

They have to be stopped!

[birdman]

I like the concept, but I think they're grossly under-emphasizing the energy needs for the unit.  It takes X amount of energy to gassify a specific volume of water at a specific pressure. That's straight physics and no miracle invention will change it. Looks like what they've accomplished is ramping up efficiency a significant amount, a feat impressive in it's own right.  I wonder how well the efficiency increases will scale.

Brad

Yes, but nothing says you can't use that energy again.
What the system does is boil the water (X energy per unit mass), pressurize the vapor (raises boiling point) with additional energy cost of about 0.02X
Then since that water will condense at a temperature above the boiling point of unpressurized water, transfers the heat to new incoming water, of which about 0.97X gets transferred.  So voila, 20x as much water as just straight heat and let it cool.
No magic, just a system engineering viewpoint that energy costs more than complexity.