Thursday, January 23, 2014

Fred's Water Idea

I see the Times- Standard followed up this morning on my look at our water supply. Ruth Lake is at 55% capacity right now.

I've been thinking lately how much water ends up each morning on lawns and grass around here. Sometimes it's just sopping wet. If you could soak all that up I wonder if it might amount to a fair amount of water. But how would you collect it? It would be impossible to try an mop it up.

It struck me this morning there might be a way around that: take the water out of the air first using a huge dehumidifier. 

Back in the late 70s I bought a dehumidifier from Sears because the little shack I had in Cutten was so cold and damp. Not only did it warm up the house, it really sucked a lot of water out of the air. 

I was amazed when I first turned it on how quickly the water reservoir filled up. It held maybe three gallons and I emptied it every couple of hours it seemed, at first. As the air dried out I emptied it less and less until it would take days to fill, but that was in a relatively finite source of water- the inside of my small house.

When the Matteoli's house flooded years ago they had a carpet guy come in to help clean up. He brought three or four commercial dehumidifiers in to dry things out. The reservoirs on those held at least five gallons of water if not more. Took days, but it dried everything out. 

What if you had even bigger dehumidifiers? Something you set outside that would suck the water out of our cold, damp air around here non- stop? I wonder how much water that would amount to?

Ok. Maybe not enough to water crops or even the home garden but I bet it would be a fair amount here in northern Humboldt. Maybe even enough for the average home's use per day? I don't know, but it would be interesting to try. Problem is, it probably wouldn't work at all in the drier places like Sacramento or Sonoma County that really need the water.


At 10:20 AM, Anonymous Anonymous said...

They use a very large amount of energy. That is why they warmed your room. Not an efficient water source. Nice try tho.

At 10:23 AM, Anonymous Anonymous said...

Wrong 10:20. For a guy who doesn't believe man-caused global climate change is occurring, monolithic dehumidifiers are a grand idea. I'm sure our redwood forests would love them too. It's not like redwoods need coastal fog or anything. Oh, wait...

At 12:39 PM, Blogger Fred Mangels said...

They use a very large amount of energy.

Not so sure about that, but desalination plants use a lot, too.

I can't remember from when I was using one, but that was back in the late 70s. I don't recall any big spike in electrical use. As best I remember the only moving part was a small fan.

When the Matteoli's house flooded and the commercial machines were drying out their house, I commented to the carpet guy that the Matteolis would probably be hating their next electric bill. He didn't seem to think that much of a concern and said the machines really didn't use much power.

I was just talking to a friend who has two dehumidifiers. She said she thought they used a lot of power and noticed it on her electric bill. Then again, she had to admit a guy was also doing some remodeling and using power tools at her house at the time in question.

It's not like redwoods need coastal fog or anything. Oh, wait...

Unlikely to be a problem as the amount of water drawn from the air would be a drop in the bucket to total moisture content even if everyone in Eureka was running a commercial size dehumidifier. At least here on the coast we have hundreds of square miles of ocean providing humidity that we could never suck dry.

My friend's lawn was covered in dew this morning. I told her it would be interesting to see what effect a dehumidifier might have on it if you started the machine at, say, 5pm the day before and let it run all night.

How much water would it draw from the air by morning? Would it prevent the formation of dew? If so, would it just prevent it within a short radius from the machine, or over a large part of the lawn?

It would be an interesting experiment. She offered to drag one of her machines out on the lawn to give it a try. I told her not to bother, but if it was my house I might well have given it a try.

At 12:47 PM, Anonymous Anonymous said...

They do use a lot of juice to run. and they are more efficient if the space is already heated to 65F so de-icing cycles don't have to run.

At 12:59 PM, Blogger Fred Mangels said...

What it probably boils down to- no pun intended- is how much water you'd get for power used, and that applies whether they use a lot of power, or not. How much energy are you willing to use for a given amount of water?

Heck, I'd love to try sticking a dehumidifier out in my yard overnight just to see how much water I'd get, among other things. I'm not sure if it would be worth it to run one 24 hours a day.

How would it compare to the costs vs. benefits of desalination? And there are desal plants being built in the state as I write this. Desal is currently THE most expensive way to get potable water. Would dehumidifiers be more cost effective per gallon? It would be interesting to compare.

At 1:31 PM, Blogger Stephen said...

There are devices now called dew catchers that can catch and store dew water that really is plentiful everywhere on earth, even in the deserts. I saw an internet news article about a large dew catching Billboard in Chile I think it was. Dew catching will be catching on in future water shortages.

I've been working on a desalinization water intake screening design that won't suck up fish and other living things.

Hey, anyone out there a computer code tech or into advanced computer design by any chance? Funny but in the last month three of my old invention ideas hit the news with others with money to develop them. It seems I serendipenously invented Google Glass concept three years ago and now I have three more wearable tech concepts to develop and am looking for a tech partner. Or investors. I'm in the phone book.

At 1:57 PM, Blogger Fred Mangels said...

Thanks for the heads up, Stephen. I guess I'm not the only one to come up with this idea but others are way ahead of me. Just doing a quick Google for "dew catchers" brings up all kind of links. This one is commercially available and seems to be being used in Africa:

Just from a quick glance, though, it really seems to be more of a dehumidifier than something catching dew. Small difference, I suppose.

There's another link in there to a site that designed an actual dew catcher that you take camping, set it out and it collects dew into a container to use for drinking water later in the day.

The big question remains, would this be more cost effective than desalination in widespread use?

At 2:05 PM, Blogger Fred Mangels said...

Taking a closer look at that one link, they show two models available. The small one- and I'm not sure how big it really is or how much it costs- supposedly produces 20 to 30 liters per day.

The large, trailer mounted one produces up to 1000 liters a day. I believe a liter is a bit less that a quart, so I'll just guess that's maybe 200 gallons or more a day? That would be enough for an average household....I think.

The question is how much it costs to buy and operate. It also says their units work best where humidity is over 55%, which means it would easily work here. Still, how much would you be paying per per gallon?

At 7:51 AM, Anonymous Anonymous said...

I think it would just be easier to pay algore his carbon tax that he's been crying about for the last 10 years because paying a tax to the corporations that are causing the pollution Will fix it right
I mean it couldn't be that we're just going through a natural cycle because its never been this dry before oh wait that's not what the old timer say they say back in 74 it was just as dry if not worse and some climate experts are saying that the last hundred years has been the wettest hundred years in California record


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