dehumidifier as a watermaker

[Randyonr3]

So this morning I get up and as always, durring the winter time, and running the "dehumidifier" I have to empty the bucket under it..
We only run it about 8 hours or so at night while sleeping but every morning, I'm dumping about a gallon of water..
Now we've got a watermaker on board but for some that cant afford a watermaker, A simple dehumidifier might be an emergency water sorce if you've got the amps to push an inverter..
It would be an interesting idea if someone wants to put the numbers together........

[Pete7]

How would you stop legionnaires disease for example? However, rather than drink it why not stick it into the batteries.

Pete

[Cheechako]

Interesting thought... how about a ultraviolet filter the water passes through on the way to your tanks? How many amps does a de-H draw? Why not take water out of the air instead of out of the sea...?

[djmarchand]

OK, irrespective of health and taste (yucchh!) here are the numbers:

To make a gallon of water from a dehumidifier you have to cool the air to the point where the moisture will condense. So that will require a minimum of 1000 btu per lb of water or about 8,000 btu per gallon. Real world usage may be several times higher.

8000 btu/gal is about 2,500 watt hours per gallon.

The most efficient R/O watermakers (Spectra) use about 1 amp at 12 V to make 1 gallon of water or 12 watt hours per gallon.

No comparison.

David

[redsky49]

Water that has condensed on the fins of the coil (which are constructed either of aluminum or occasionally copper) typically contains numerous trace chemicals and precipitates, and is definitely not potable. In addition, the possibility for biologic growth would indicate against use of any water recovered in this manner. Condensate pans, regardless of the application, develop substantial build-up of fouling and should be cleaned on a regular basis. Several proprietary cleaners are available for this.

In addition, as stated above, the energy required to produce this moisture makes such a system impractical.

In an emergency distillation might be a more practical approach.

[Steve_T]

This is an old thread, but since I have been researching this myself, it needs to be updated.

1. Energy star rated dehumidifiers must produce between 1.2 and 1.8 liters of water per kwh in order to be certified. Larger units are more efficient. I would think that even more might be achieved using the highly efficient 12 refrigeration systems based on Danfoss compressors.

2. Commercial units designed specifically for producing drinking water are available.

3. As with any drinking water system, cleanliness is the order of the day. There is nothing special or particularly dangerous about condensing water out of the air, but all water handling systems need to be disinfected either on a continuous or on a periodic basis.

[a64pilot]

First post did state it's use an emergency source of water. If there were no other source, I'd drink it, happily and deal with the consequences if any, later.
It is essentially distilled water and I think a good source for batteries if nothing else.

I think condensing drinking water has been a method that has been around a LONG time. Unless I'm mistaken, the spoof message to see if the Japanese target was really Midway was that their water condenser was broken.


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[Captain Pappy]

Perhaps in an emergency situation, one can filter the water through a Lifestraw device? Even if not, it is concepts like yours that inspire the best of human ingenuity. Perhaps someone will now invent a cleaner dehumidifier system to utilize this idea.

[Cheechako]

Mold, Legionaires disease etc would be a problem.