Atmospheric Water Generators (HOA, appliances, how much)

[Due]

Atmospheric Water Generators aka Water from Air Generators have intrigued me.

Reading that thousands of similar machines are in use by individuals, companies, and military throughout the world makes it seem a viable option to private or city water. The generators (about 5 liters a day to 5,000+ liters) range in price from approx..$2,000-$100,000 (varies with water production-capacity and some have an independent power supply). They use a fair amount of electricity, but if a PV system (with enough capacity) is available, they should be minimal cost to operate.

The concern is maintenance because most of the machines must be cleaned internally to keep the water drinkable, although there is one manufacturer which claims they have perfected the system to require minimal maintenance.

What are your thoughts?

[oregonwoodsmoke]

There's lots of atmospheric water generated in Hawaii without the us of any machine.

[OpenD]

They've been around for years, but they are expensive and they are pigs for electricity. They are considered to have the worst carbon footprint by far of all methods of obtaining potable water, something like 3X the energy cost of desalinating sea water.

Passive atmospheric water collection, on the other hand, can be practical in some environments. I have many Hapu'u ferns on my property, and it's fun to watch the water droplets form on their leaves and then drip to the ground from the fringed edges. Research has shown that the ground directly underneath their foliage contains 1/3 more moisture than the ground elsewhere. Some people have emulated this natural process using canvas curtains or hanging plant walls.

[Due]

Originally Posted by OpenD

They've been around for years, but they are expensive and they are pigs for electricity. They are considered to have the worst carbon footprint by far of all methods of obtaining potable water, something like 3X the energy cost of desalinating sea water.

You are correct, but a PV system doesn't have much effect on the carbon footprint and if the PV system has excess power available, why not use it?
Desalinating sea water is not a viable option.
[I should've made it clear that this would be for personal use]

[KaraBenNemsi]

Why do it with electric power when simple mechanisms work to desalinate water?

Water Advocate.org - Solar Desalination

Only needs land where desert meets the ocean. And our planet has many million miles of that.

[OpenD]

Originally Posted by Due

You are correct, but a PV system doesn't have much effect on the carbon footprint and if the PV system has excess power available, why not use it?
Desalinating sea water is not a viable option.

If you literally have no rain water catchment or well or county water available, and no access to saline or salt water to process in a solar still then I think the best bet would to have your water hauled... 4,000 gallons will cost maybe $200-250 delivered. After all, running a residential sized atmospheric water generator off solar energy is likely to only yield drinking water quantities, not enough for all your household needs.

On the other hand, if you want to try it, I wouldn't spend $2K to experiment. There's a DIY item on Instructables that shows how to cobble one together for a little over $300, using a $225 home dehumidifier and a $30 ceramic dome water filter, plus miscellaneous bits.

DIY Atmospheric Drinking Water Generator

I'd say you could do it for less, because I see dehumidifiers much cheaper at garage sales, since a lot of people seem to buy them and then don't want to use them again once they get their electric bill.

On the other hand I've never seen a water filter setup like that for $25. The ceramic dome element alone costs that much and is good for 6 months use. But you can easily make a drip filter setup like that with two buckets with lids, the filter and a spigot for less than $50, and maybe find a dehumidifier for under $100. I found a really nice, might-as-well-have-been-new $250 Kenmore for $60 at a garage sale.

A Practical, Life-Sustaining Water Filter | Monolithic


Good luck!

[Due]

OD-
You are spot on: we don't have "rain water (not enough), catchment (ditto), or well (provided by a private company but at high rates) or county (none) water available, and no access to saline or salt water (1/4 mile away and 400' down) to process in a solar still"

I guess we could haul water, but above-ground tanks are prohibited in our area. To put one underground would require dynamite and that's not going to happen.

Thanks! for the feedback everyone.

[OpenD]

Originally Posted by Due

OD-
You are spot on: we don't have "rain water (not enough), catchment (ditto), or well (provided by a private company but at high rates) or county (none) water available, and no access to saline or salt water (1/4 mile away and 400' down) to process in a solar still"

What is it there, Kohala Ranch Water? Even the most expensive private water company... and they are all regulated by the PUC... will still be far cheaper than hauling water. What is it up there, $10 per 1,000 gallons? So you learn to conserve water, and be glad you have the choice.

I guess we could haul water, but above-ground tanks are prohibited in our area. To put one underground would require dynamite and that's not going to happen.

Sounds like your HOA rules are designed to keep out the riff-raff.

A couple of loose thoughts... you might be able to get an above-ground tank approved if it doesn't look like one. I saw a picture of one that was built as a low rectangular concrete tank under a plantation style porch. There's no way anyone could tell it was there. Another house I know has a carport on one side of the house, and a similar structure on the other side which entirely conceals an old-school above-ground cedar tank.

Oh, and dynamite is kinda old-school today for digging into lava for cesspools, septic tanks, and in-ground water tanks. A hammer tool on an articulated arm on a frontloader is what I watched a contractor use to dig out a big new cesspool for a neighbor. It's not cheap, but it's do-able.

Meanwhile, if you are interested in pursuing the Atmospheric Water Generator, you're still going to need to solve the water storage issue. Average per-capita water use on the Big Island is estimated at 100 gallons a day for drinking, cooking, showering, toilets... far, far less than average use on the mainland, but still, more than you can probably handle for long with a 330 gallon tote. But before making any big investment in equipment I'd try the DIY project I suggested, just to get a handle on how much water you can reasonably expect to be able to harvest at that location.

[Due]

Originally Posted by OpenD

What is it there, Kohala Ranch Water? Even the most expensive private water company... and they are all regulated by the PUC... will still be far cheaper than hauling water. What is it up there, $10 per 1,000 gallons? So you learn to conserve water, and be glad you have the choice.

Yes: KRW, it's currently $7/1,000. We conserve with updated drip irrigation and efficient appliances, but I like to grow fruit trees plus need a large grassy area for our dogs: that takes extra water.

[Sounds like your HOA rules are designed to keep out the riff-raff. ]
They are strict: riff-raff is not in the docs though .

[get an above-ground tank approved if it doesn't look like one. I saw a picture of one that was built as a low rectangular concrete tank under a plantation style porch. There's no way anyone could tell it was there]
That might work! There is a large enclosed storage area (about 800 sq.ft.) under the house at ground level. In addition, this would make a great reservoir in case of a fire.

[dynamite is kinda old-school today for digging into lava for cesspools, septic tanks, and in-ground water tanks. A hammer tool on an articulated arm on a frontloader is what I watched a contractor use to dig out a big new cesspool for a neighbor]
Yeah, I knew....was just trying to be funny. I have a dry sense of humor

[But before making any big investment in equipment I'd try the DIY project I suggested, just to get a handle on how much water you can reasonably expect to be able to harvest at that location.

Thanks!!

[OpenD]

Originally Posted by Due

We conserve with updated drip irrigation and efficient appliances, but I like to grow fruit trees plus need a large grassy area for our dogs: that takes extra water.

Gotcha. For those purposes i would investigate passive methods of harvesting atmospheric water, such as fog fences, air wells, etc. I've read that native Hawaiians grew food in that area by using small piles of rocks to gather atmospheric water on the mauka side, where they would grow plants.