chemical dehumidifiers

[kpgraci]

I bought some of those damp-rid closet dehumidifiers, the ones that come on a hanger and have a plastic bag attached so you can see how much water they are removing - I put one in the cabin and in three days it was full.

I'm not paying for electric at my slip, so are there any effective chemical dehumidifiers with enough capacity to work in what is obviously a high humidity environment?

Of course at about $3 a pop for the damp-rids an electric hookup is $15/mo last I checked, less usage - how much current does one of these portable marine dehumidifier draw?

OK - this one says 1.1 amps, but it's an air dryer - not really a dehumidifier, sound like it just warms and criculates the air - maybe good enough?

http://www.amazon.com/Davis-Instrum...371745442&sr=8-1&keywords=marine+dehumidifier

 

[Eddie7045]

The trick is to raise the temperature above what it

is outside. Ideally you want to maintain it above 50 degrees if possible. A commercial fisherman that I knew used a baby crib heater as it gave off a gentle heat for safety reasons and helped a lot to eliminate condensation. Here in Oregon we use a lot of chemical dehumidifiers also but as a secondary measure in closets relying on heating as the primary method.

 

[tkanzler]

My FIL used to use a 75 or 100W light bulb in the engine room of his 42 ft trawler to keep condensation at bay while in its slip. Watts is watts, and it was enough to keep it above the dew point in the NYC area, year-round. Might not be enough in the gulf coast, though.

 

[Bad Obsession]

The chemical dehumidifiers work very well. I keep three in the cabin of the Catalina 30. It makes a noticeable difference over the winter.

 

[Don S/V ILLusion]

Save your money. You can buy the same desiccant as that found in these bags much cheaper at any ag, formulator or supply store and probably most large hardware stores.

It is commonly referred to as gypsum which is calcium sulfate but others are equall effective. Just google list of desiccants for info. A few kitchen collanders and you're all set.

By the way, raising the temp doesn't change the amount of moisture in the air.

 

[kloudie1]

Hey, ken.. Practical Sailor just did a comparison test of the different dehumidifiers. An interesting one is made by EVA-DRY
http://www.eva-dry.com/products/eva-dry-1100-petite-dehumidifier/
A peltier effect dehumidifier that draws 22 watts (three kilowatt hours per week)
Its bigger brother, the 2200 draws 72 watts (about 12 kwh/week)

On my Cleco bill, running a battery charger and an air conditioner in "dehumidifier" mode .. The actual charge for electricity is only $2.43, (38 KWH at $.064/kwh) but after all fees and stuff, the total is $15.18.

A regular big dehumidifier worked really well for me for a couple of years, but it is a real hassle to pull off the boat when ya leave and re-install when ya return.
http://www.homedepot.com/p/LG-Elect...difier-WAS-198-LD301EL/202848118#.UcNbnztNa84

 

[kpgraci]

I'm intrigued by the low cost of electric, but my boat is not setup for 110 (or is it 220?). I'd need a marine grade connector, circuit protection, who knows what else (well, someone here does I'm sure). Best leave that as a future project.

 

[kloudie1]

OK.. Thought ya had a 115V 30 ampere outlet at the slip to just plug into..

 

[Eddie7045]

Condensation

"By the way, raising the temp doesn't change the amount of moisture in the air."[/quote]

Which is why you want to raise the temperature and keep it there rather than condensing on walls, in fabric and other things.

 

[Doc_holiday]

Raising the temp lowers the Relative humidity but it doesn't change the grains of moisture in the air. As recently mentioned condensation is what you want to avoid.

Deasicants can be rejuvenated by heating them up (off the boat). I just don't know that you could have enough on the boat to dry it. You'd be we'll served to bring in fresh air as long as the enthalpy of the air outside is lower than the inside.

Note to self, see about using a dual enthalpy economizer control to bring on ventilation fan. Hmmm maybe I'll work on that

 

[Don S/V ILLusion]

"By the way, raising the temp doesn't change the amount of moisture in the air."

Which is why you want to raise the temperature and keep it there rather than condensing on walls, in fabric and other things.[/QUOTE]

Desiccants don't understand (ambient) temperature variations

 

[Eddie7045]

Don,

Desiccants don't understand (ambient) temperature variations [/quote]

Actually they do. They absorb moisture in colder air and disperse it in in warmer air. Unless an individual was willing to change the desiccant every couple of days then a better solution is to raise the temperature of the cabin as commercial operators do. In the moist Northwest we deal with this a lot.