[PeakOiler]

I'm not spamming the board ya'll, but I thought some readers might miss the reply I made in a current post on this forum, and since I thought this topic may be of interest to people like Matt Savinar, (since he's getting into selling solar products,) I wanted to post the message again.

I've been using one of SolAqua's solar water distillers for nearly four years now for about 99% of my drinking and cooking needs. I began distilling the city utility water, but the utility water is so hard, I was constantly needing to clean the calcium carbonate (limestone) out of the basin.
So now I only distill naturally soft rainwater. There's no oil-based organics in rainwater either, (or at trace levels only, less than what leaches from plastic bottled water.)

Here's a few interesting excerpts from SolAqua:

"The basic principles of solar water distillation are simple yet effective, as distillation replicates the way nature makes rain. The sun's energy heats water to the point of evaporation. As the water evaporates, water vapor rises, condensing on the glass surface for collection. This process removes impurities such as salts and heavy metals as well as eliminates microbiological organisms. The end result is water cleaner than the purest rainwater. The SolAqua still is a passive solar distiller that only needs sunshine to operate. There are no moving parts to wear out."

"The first "conventional" solar still plant was built in 1872 by the Swedish engineer Charles Wilson in the mining community of Las Salinas in what is now northern Chile (Region II). This still was a large basin-type still used for supplying fresh water using brackish feedwater to a nitrate mining community. The plant used wooden bays which had blackened bottoms using logwood dye and alum. The total area of the distillation plant was 4,700 square meters. On a typical summer day this plant produced 4.9 kg of distilled water per square meter of still surface, or more than 23,000 liters per day. This first stills plant was in operation for 40 years!"

" Obtain a US$135 FEDERAL TAX CREDIT for purchasing a single solar still in 2006-07. The House and Senate approved a 30% tax credit bill for the installation of a solar system on your home or place of business, and President Bush signed the bill into law on August 8th 2005. There is a maximum $2,000 for residential applications and no cap for commercial applications. Additonal state credits may apply in your state. Call your Tax Preparer for information for your particular case."

I think SolAqua is a member of the Texas Solar Energy Society.
SolAqua

[PeakOiler]

Here's some math:

I paid $426.79 for the water still on 7/30/02. My best estimate is that it produces on average about three liters per day.

I checked the price of designer plastic bottled water recently at the local grocery and they were selling thirty-two 16.9 oz bottles for $4.99.

So that's $0.0092/oz, $1.18/gal, or $0.31/liter.

Payback estimate:

456 days

I think I'm ahead now.

[dinvinci]

I'm intrigued. What's your rainwater catchment system like? I would like to set up a rainwater catchment system but we have an asphalt-shingled roof and I've been told this is not a very suitable collection surface in terms of drinkable water. The cost of a new metal roof of course is pretty substantial, obviously, in addition to the costs of installing a cistern and pump and other peripheral devices. Since we only pat $30/month for water now it doesn't seem cost-effective....of course then I find myself wondering, but what if we couldn't get clean water at ANY price? I'd really be wishing I'd installed that roof and cistern and everything back when it was still relatively easy to do so.

[PeakOiler]

$this->bbcode_second_pass_quote('dinvinci', 'I')'m intrigued. What's your rainwater catchment system like? I would like to set up a rainwater catchment system but we have an asphalt-shingled roof and I've been told this is not a very suitable collection surface in terms of drinkable water. The cost of a new metal roof of course is pretty substantial, obviously, in addition to the costs of installing a cistern and pump and other peripheral devices. Since we only pat $30/month for water now it doesn't seem cost-effective....of course then I find myself wondering, but what if we couldn't get clean water at ANY price? I'd really be wishing I'd installed that roof and cistern and everything back when it was still relatively easy to do so.

[MattSavinar]

$this->bbcode_second_pass_quote('PeakOiler', 'I')'m not spamming the board ya'll, but I thought some readers might miss the reply I made in a current post on this forum, and since I thought this topic may be of interest to people like Matt Savinar, (since he's getting into selling solar products,) I wanted to post the message again.

I've been using one of SolAqua's solar water distillers for nearly four years now for about 99% of my drinking and cooking needs. I began distilling the city utility water, but the utility water is so hard, I was constantly needing to clean the calcium carbonate (limestone) out of the basin.
So now I only distill naturally soft rainwater. There's no oil-based organics in rainwater either, (or at trace levels only, less than what leaches from plastic bottled water.)

Here's a few interesting excerpts from SolAqua:

"The basic principles of solar water distillation are simple yet effective, as distillation replicates the way nature makes rain. The sun's energy heats water to the point of evaporation. As the water evaporates, water vapor rises, condensing on the glass surface for collection. This process removes impurities such as salts and heavy metals as well as eliminates microbiological organisms. The end result is water cleaner than the purest rainwater. The SolAqua still is a passive solar distiller that only needs sunshine to operate. There are no moving parts to wear out."

"The first "conventional" solar still plant was built in 1872 by the Swedish engineer Charles Wilson in the mining community of Las Salinas in what is now northern Chile (Region II). This still was a large basin-type still used for supplying fresh water using brackish feedwater to a nitrate mining community. The plant used wooden bays which had blackened bottoms using logwood dye and alum. The total area of the distillation plant was 4,700 square meters. On a typical summer day this plant produced 4.9 kg of distilled water per square meter of still surface, or more than 23,000 liters per day. This first stills plant was in operation for 40 years!"

" Obtain a US$135 FEDERAL TAX CREDIT for purchasing a single solar still in 2006-07. The House and Senate approved a 30% tax credit bill for the installation of a solar system on your home or place of business, and President Bush signed the bill into law on August 8th 2005. There is a maximum $2,000 for residential applications and no cap for commercial applications. Additonal state credits may apply in your state. Call your Tax Preparer for information for your particular case."

I think SolAqua is a member of the Texas Solar Energy Society.
SolAqua

[Loki]

Looks interesting. I played around with these as a kid growing up in Arizona--don't remember getting a ton of water from them (but mine were pretty primitive). I assume central Texas gets plenty of sun. How does it work when it's cloudy? I live in western Oregon and it gets cloudy here on occasion.

I recently purchased a Big Berkey filter from eBay. Unfortunately the sender didn't pack it very well and all the filters broke. He refunded my money, so I basically got the shell for free. But it goes to show how easily something like this can be put out of commission. Plus I don't think it would filter out the toxins from water collected off of my asphalt-shingle roof.

[PeakOiler]

$this->bbcode_second_pass_quote('Loki', 'L')ooks interesting. I played around with these as a kid growing up in Arizona--don't remember getting a ton of water from them (but mine were pretty primitive). I assume central Texas gets plenty of sun. How does it work when it's cloudy? I live in western Oregon and it gets cloudy here on occasion.

I recently purchased a Big Berkey filter from eBay. Unfortunately the sender didn't pack it very well and all the filters broke. He refunded my money, so I basically got the shell for free. But it goes to show how easily something like this can be put out of commission. Plus I don't think it would filter out the toxins from water collected off of my asphalt-shingle roof.

[Caoimhan]

Distillation by this method will remove:

1. Microbes (but there's a caveat in that microbes can be reintroduced to the condensate from the surface glass, collection trough, tubing, etc... Good sanitation of these surfaces will help keep the final microbe count low).

2. Heavy metals

3. Salts (This is not necessarily good. Some dissolved salts provide nutritional value.)

This method will not necessarily remove:

1. Volatiles. They evaporate and condense, too. Unburned hydrocarbons from exhaust can be among these. Alcohol would be among this class, too, though I don't expect alcohol to be in rainwater. But who knows if someone might try to distill Vodka?


Also, deionized water is not necessarily healthy for you, though this is controversial. Water is a solvent, and it WANTS to have salts dissolved in it. Some say that distilled water may strip minerals from your body.

Adding some healthy minerals back into distilled water will not only counteract the solvency of the water, but will also make it taste better.

[Loki]

Caoimhan, thanks for the info. Makes sense. If distillation doesn't remove volatiles, what does? I'm thinking of installing a water barrel, but I have asphalt shingles. I rent, so I can't replace them or cover them. Having a supply of non-potable water would be better than nothing, but it would also be nice to be able to safely drink it.

[PeakOiler]

Thanks Caoimhan for the info. But what I'm after is some actual simple distillation data from gas chromatography (GC) and/or liquid chromatography (LC) analyses of distilled rainwater off an asphalt-shingled roof.

I have some contacts with a TCEQ lab in Houston, so if I can get some rainwater samples together, (if I can find someone to collect some rainwater from an asphalt-shingled roof for me and then I'll distill it,) I could submit the "before distillation" and "after distillation" rainwater samples for analysis by GC/GC-MS/ or LC.

I learned today that asphalt includes a class of chemicals called PAH's, polyaromatic hydrocarbons. (PAHs are also emitted from burning charcoal or wood for grills for example.) Simple distillation will remove some, but probably not all the PAHs. Double distillation would be best.
This is also why the first 10% "head-cut" is discarded during batch distillation.

Part of my resume:
BSc. Chemistry, UT-Austin 1987

[Caoimhan]

$this->bbcode_second_pass_quote('Loki', 'C')aoimhan, thanks for the info. Makes sense. If distillation doesn't remove volatiles, what does? I'm thinking of installing a water barrel, but I have asphalt shingles. I rent, so I can't replace them or cover them. Having a supply of non-potable water would be better than nothing, but it would also be nice to be able to safely drink it.

[PeakOiler]

I've contacted a friend of mine in suburbia Austin who has been collecting rainwater off his conventional shingled tar-paper roof for irrigating part of his garden. The ca. 70 US gallon rainwater barrel has been in use for at least three years, so a good representative sample of the rainwater can be collected. I have some spare HDPP (high-density polypropylene) water sample bottles at work that I can borrow to collect some samples.

We're going to set up the solar water still at his house next weekend and distill a batch of rainwater.

We'll keep you posted on the results, providing the regional environmental investigator can get the Houston TCEQ lab to analyze the samples.

I'll keep you posted.

And I agree that an activated carbon filter would remove PAHs, but that usually means using a pump.

[Loki]

PeakOiler, I'm definitely interested in the results. I've heard mixed things about using water that has drained from asphalt shingles, so it would be nice to get some hard data on what exactly is in the water and in what concentrations. One person I talked to said they killed their garden using water from an asphalt-shingled roof, another person said they grew up drinking this water untreated and using it to water their garden, and they never had a problem.

The shingles on my roof are nearly brand new, so I would venture to guess that they're releasing toxins in relatively high concentrations. I'd be happy to send you some samples, but I have no idea what kind of container to use. Also, we're currently in the dry season, so it may not rain again for a while.

[PeakOiler]

First of all, I apologize to those expecting analytical results of distilled rainwater as described above. The contacts I had with local labs are no longer there. Bottom line: collect rainwater off a metal roof for best results.

Anyway, here is a picture of the solar water still "in action" on this summer day:


(I'm playing with a new digital camera.)

A picture is worth a thousand words it is said, so here's a few of them:

In the background is an unfinished deck around one of the 1,550 gal water tanks, and a grape vine is growing up the wire to the 36-watt solar panel that charges a 100-amp-hr battery. (I need to prune that vine...) Also note the sundial on the deck, next to the pots of baby lemon trees and a couple of banana pepper plants. Adjacent to the sundial, and further in the background, is a small solar panel that charges the battery to a motion-activated floodlight on the front porch.

The still will produce about 4-5 liters of potable water today.

[PeakOiler]

How much would it cost to buy 5 liters of bottled water every summer sunny day from the grocery store where you live? I don't know what the price of bottled water is currently since I never buy bottled water from the grocery store.

I'll leave it as an exercise for each reader to calculate the "payback time" of a solar still from the water produced vs. store-bought bottled water.

Got good solar insolation?

Frank Herbert wrote:

"Water is life".

[PeakOiler]

Today I reassembled the solar water distiller after a storm blew it over and broke the glass a couple of weeks ago. The new glass pane cost $36 and a tube of food-safe grade silicone sealer cost $4. I cleaned the lime residue from the basin (since I had distilled some of the city's water), cleaned the new pane, and then I rinsed the basin thoroughly and refilled with rainwater.



One can see the condensate already forming on the underside of the glass.

I still have to attach the 5 gal. plastic receiver bottle. I would eventually like to use a glass receiver, since the plastic bottle will deteriorate after so many years in the sun. The perimeter gasket also has to be reattached, but I'm waiting for the sealer to set.

Then I'll distill a few gallon batches of water, discard those, and continue on...

You got to love using the only working fusion reactor in the solar system...

[PeakOiler]

After I sealed the 4' x 2'5" x 1/8" glass pane yesterday morning, I allowed the distillate to rinse the underside of the glass all day yesterday. This morning I attached the inlet port funnel, the outlet tubing to the new 5-gal plastic bottle, (partially covered with reflective tape), and flushed the basin with about 4 gallons of filtered rainwater. The bucket used to catch the basin flush overflow was emptied on nearby plants. Today was a mostly sunny day and about another 3 liters has been distilled so far. (Another 1-2 liters will be distilled during the remainder of the day and evening.) The distillate today will also be "discarded" on nearby plants. Tomorrow I'll taste-test the distillate.



Edit for details: A glass stopper is placed into the tubing of the inlet port at the bottom of the blue funnel after filling and flushing the basin.

The receiver tubing is attached to a hard-plastic tube (using a hose clamp) that was inserted through a hole drilled through the screw cap of the bottle. A glue gun was used to seal the tubing that was inserted through the receiver bottle's screw cap. The only vented opening to the still is the basin overflow tube, so the still is essentially designed around the Pasteur flask. (Google Pasteur flask).

[no_wuckin_ferries_mate]

Here is something similar.

Sounds like a good idea, however, I have no experience with it.

Actually I have been following that website for years now, and have the impression they
won lots of awards and prizes, but it is not clear for what.

The product is not available, and has not been during the past few years.

They do not seem to be keen to sell at all, so I am not sure what is behind it.

I someone can manage to buy one please let me know.

[Quinny]

I've not managed to buy nothing!

[no_wuckin_ferries_mate]

$this->bbcode_second_pass_quote('Quinny', 'I')'ve not managed to buy nothing!