Is this a crazy idea?

[Lodesman]

For your needs I would think a smaller WM that could be powered by your running engine would be more than sufficient. Since you seem to want to "mad scientist" a solution, you might consider making a watermaker. Maybe Lepke and the others that have been there could give the benefit of their experience, to lessen the risk. There's a thread with some other links: http://www.cruisersforum.com/forums/...mp-118751.html

[Mike Banks]

I think you have over-estimated the amount of power a water maker uses--or you have one way too large for the requirements of a normal cruising yacht.

As to the suitability of the air conditioner condensate for drinking purposes--of course you can drink it--and it makes good battery water too as long as you collect it in a clean container not contaminated by salt spray.

However--for drinking purposes--it would be safer to chlorinate it. I use one Milton tablet (sodium hypochlorite) in 20 litres of water and let it stand overnight. OK--so it tastes of chlorine--it is safe.

[MrPix]

I figure I'm close to retired and can afford a little science project, but I can't afford a water maker. The occupation of my mind and hands alone is worth the expense. So, to business!

The idea of using water condensate from a phase change AC has been ruled out. Though the system can be completely safe/non-toxic, it looks like about 90% of you wouldn't drink water as a guest on my boat if I offered that Fair go!

So, there has to be another way to make a plate cold, efficiently, to get that amount of condensate. Or, a lower pressure RO system.

A couple of people have suggested running the pump as an accessory on the motor. It is a new Volvo Penta with 68 hours on it, still under warranty. I don't want to mess with that until it's out of warranty. I hope you understand.

Another option would be a small evaporator/condenser system using a small 12V heating coil. This would use sea water as an input, but it would need watching in case it boiled dry, and I think it would be electrically expensive to run.

I'm open to any ideas. This is just a hobby/enthusiast project by a tinkerer who is on a low budget right now.

Unless anyone here upgrades their RO system and wants to pass their old one onto me for a fair price, I am stuck working out my own system. I'm ok with that. Sail your own boat, I say

[MrPix]

Originally Posted by Mike Banks

I think you have over-estimated the amount of power a water maker uses...

No, I looked at the spec sheets. Power isn't my issue. A nice problem to have would be if I overestimated the amount of $$$$ a water maker uses

I can fit two 160W panels on my boat. Regardless of anything else I do, if I am going to run this on solar, it will be on 320W and gulf coast weather.

[Rorzech]

Sure but you must remember those aluminum fins collecting the condensate along with all the other toxic stuff in the air is a real toxic soup. I'd pass on that thank you !

[Compass790]

Originally Posted by Lepke

I started like the original poster. I thought ready made watermakers were overpriced and had expensive filters, membranes and parts. My homemade water maker makes 40-50gl/hr. Currently it's HP pump is belt drive on a Perkins generator. In getting to a decent system I went thru many changes/failures and a lot of wrong advice. I went thru many AC & DC HP pumps, membrane sizes and so on. If I'd have been smart, I would have bought one of Cruise RO's setups. I'm sure I spent at least double the price of one of their best systems. But instead I screwed around trying this and that (to save money).
The moral of the story is: it's better to allow someone some profit on their engineering than to waste a ton of money doing the engineering yourself.

Yes I know what you mean. Once sailed for an owner about whom the local marine store said ,John has a philosophy " why buy it for $5 when you can make it for $60" BUT people have different standards when they arent being paid for their time or are retired/dont have cash. John simply preferred having a project. I'm talking time cost here but if the material cost exceeds a store bought item yes it's hard to see the justification.
You aren't alone making that mistake Lepke, been there, done that 7 probably will again

[44'cruisingcat]

My Little Wonder watermaker makes about 2 litres per amp hour. A Spectra system about double that.

I can't see you getting anywhere close to that efficiency using a refrigeration system.

I've seen LW watermakers for sale second hand for a few hundred dollars.

[hzcruiser]

Please keep us posted here to see if your numbers work out. While you're working on it, you can always keep looking for a used WM online.

In general, cooling and dehumidifying the inside of the boat in a tropical climate would be welcomed by anyone, if the power consumption is reasonable. Even better if you also get a bit of juice out of it! You'd want to compare if closing the hatches at night and running the WM would produce a more comfy "ambiente" than guiding a little breeze through the whole boat with all hatches open.

To add my experience, I had no immediate need for a WM but after 2 years of the occasional search on ebay/craigslist/gumtree I found a 12 year old, new (army surplus) Katadyn power survivor 40E which works fine.
Doesn't produce much at all, though, about 3 lph, less than 1 gallon/h but only draws 4A@12V and is very quiet. If offshore I could run it 24/7. The pre-booster pump is a bit annoying (noise-wise) as it kicks in every minute for a few seconds...

[Compass790]

Doesn't sound crazy to me but then a lot of people think I am. Good on ya for having a crack. Keep us posted on how you get on.

[MarkusK]

Originally Posted by hellosailor

Unless the vast majority of all engineers are incompetent, a dehumidifier would be neither more officiant nor more efficient than AC, since powered dehumidifiers are pretty much just weaker versions of AC systems, or even worse, they are simple heaters.

.

You can’t compare dehumidifiers with AC just because they share some common components. One is designed for latent cooling and the other for sensible cooling. The dehumidifier will have a much better efficiency in terms of kW/lb of water removed. Dehumidifiers are used to make drinking water but that design is not scalable.

Anyway, this does not help the OP…I just needed to defend dehumidifiers.

[MrPix]

Originally Posted by Rorzech

Sure but you must remember those aluminum fins collecting the condensate along with all the other toxic stuff in the air is a real toxic soup. I'd pass on that thank you !

You mean that stuff you breathe? All that "toxic stuff" is either imaginary, easy to filter out, or something our body already knows how to deal with.

[senormechanico]

Originally Posted by Compass790

Doesn't sound crazy to me but then a lot of people think I am. Good on ya for having a crack. Keep us posted on how you get on.

Also, please ask your friends or next of kin to promise to let us know what happened after you die of toxic substances from your project.

[MrPix]

Ok, let's tackle this head on, since some people feel strongly about it. If the unit has a CE logo on it and was manufactured after 2005, it is absolutely 100% lead free. The metal contaminants are trace dissolved aluminum (the second most abundant metal on earth and a huge proportion of what we eat). If you drank 100 gallons of water, you would consume about 2 micrograms of aluminum. You might also consume about .5 micrograms of copper. It isn't chelated. It isn't readily bio-available, and would be beneficial if it was. It is not a concern, even with lifetime exposure. Your home is probably filled with copper pipes and you don't freak out about that. There may be some manufacturing by-products, like machine oil, contaminating initial batches.

The real hazard of condensate is legionella. This is quite trivial to eliminate with chemicals or filtering. It is only a problem if the water is aerosolized, so as long as I don't set up sprinklers on my deck, I think I'll be ok.

If you run plain condensate from a recent, CE approved coil through a simple sawyer mini filter, it will test as equal in purity with reverse osmosis water. Expect contaminants to be in the 15 ppm region after basic filtering for organics.

Now, if it's a pre-2005 or non-CE AC, particularly made in the US, all bets are off.

[senormechanico]

Watching with interest, although with 440 watts of solar and lifepo, we make all water we want with our Spectra, watch movies, have fridge/freezer AND use our inverter to heat water for showers. No need for engine battery charging.when we're cruising all summer in the PNW.

[wsmurdoch]

Buy one off the shelf... https://www.amazon.com/Pro-Water-Gen.../dp/B071RC68MY