Before you go off on this ill-advised tangent, consider the physics
and do a little math. See how much desiccant it's going to take to
remove even one gallon per day and then figure up the work involved in
rejuvenating it every day or two. Then, of course, there's the
energy. It takes more than the heat of vaporization of water to drive
it from the desiccant so the energy consumption will actually be
higher than with a high efficiency refrigeration-type dehumidifier.
You really only have two options - refrigeration-based
dehumidification and ventilation. The second option is only available
if there is a source of dry air available. If the outside air is as
humid as indoors then ventilation will do you no good.
It takes a relatively large amount of energy to dehumidify simply
because water has such a high heat of vaporization. That heat has to
be absorbed to condense the water vapor into liquid water. That's
something we're stuck with. The only way to reduce the power
consumption is to find a more efficient refrigeration unit and/or
reduce the moisture influx.
You may find as I did that a high SEER window AC is more efficient
than a typical dehumidifier. I found that an 8000 BTU 11 SEER window
unit was considerably more efficient than any dehumidifier available
on the local market AND it removed much more water AND it was a LOT
cheaper (about $90 vs over $200 for typical dehumidifier). I have it
sitting on a platform over the floor drain in my basement. I drilled
a hole in the bottom to let the condensate drain to the floor drain
and blocked the little tube that normally carries the condensate to
the condenser to be evaporated outside. I have an external humidistat
wired to the unit to turn it off in the unlikely event it ever dries
the basement below 50% RH.
The way to evaluate the efficiency is in terms of water removed per
unit of energy. That would normally be grams/ounces/gallons of water
per kilowatt-hour. The nameplate power consumption is, in my
experience, usually higher than actual. Actually measuring the power
consumption using a Kill-a-Watt (KAW) or equiv is the way to
accurately determine efficiency.
When I was choosing my AC unit, I carried my KAW to the various stores
and actually operated each unit under consideration.
There is one limitation to using an AC and that is the limit of
humidity reduction. ACs are designed to never bring the evaporator
below freezing and typically don't go below about 38 degs. That means
that the humidity can't go below about 40 deg wet bulb which is about
38% RH for a dry bulb temperature of 70 degrees. If you need to go
below that you'll have to get a freezing dehumidifier. This type of
dehumidifier is designed to freeze the evaporator and periodically
thaw it. Only go that route if you need the lower humidity, for the
freezing style is a little less efficient.
The best return on investment will be dollars spent reducing the
moisture influx. Sealing the concrete floor and walls, for instance,
can dramatically reduce the moisture that diffuses through them.
As part of my moisture reduction program I had the dirt next to the
house dug out to below the foundation, coated the blocks with tar and
black poly, installed a french drain and backfilled a foot or two with
gravel before replacing the dirt. I also graded the fill away from
the house to ensure that rain water didn't flow back against the
walls. I painted the inside walls with that water sealer paint that
the home improvement stores sell and I coated the floor with cement
floor paint.
It is far too humid to rely on ventilation where I live so the
moisture reduction program and the dehumidifier were the techniques
necessary. My basement went from having billowing growths of mildew
and other fungus growing on the floor studs to being pretty much as
dry as the house.
John
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John De Armond
See my website for my current email address
http://www.neon-john.com
Cleveland, Occupied TN
Don't let your schooling interfere with your education-Mark Twain
