"Tom Nie" wrote in message
...
Actually, George, it's like the recirculating setting on your car AC
instead of the outside air setting. That is, it keeps drying and redrying
the same air with only the liquid being piped outside. And so on, and so
on. Since it's an enclosed system it's highly efficient and the size of
the box can pretty well be what you want it to be.


Was, of course, talking about the heat, not the air or moisture. Since the
condensation requires cooling the coils, makes not a lot of sense to heat
the air passing over them.

A dehumidifier doesn't exhaust cool air like an AC. Unlike the car's
evaporator air discharging separately, the air passes over the condenser
so it's actually warm air discharged. The slow fan speed allows more time
for the humid air to spend around the evaporator which also helps
dehumidify without cooling the air as much. I know around here if you
brought in outside air you'd be forever trying to achieve the differential
or, another way of saying it, is that you'd be buying a lot more than a
$300 dehumidifier (and in such a small area you could buy even cheaper and
still be a Basement Model).


If air runs out over the cold coils, it's cooled, so I am not sure what
you're trying to say. The "basement" dehumidifiers have a defrost cycle
built in them where just the fan runs to pull warm air over those coils and
thaw them. Allows their use in cooler or more humid areas. You can
interrupt the power altogether with timers on a cheaper model, but you
sacrifice the humidistat control.

The squirrel cage fan is just additional air movement to prevent any
pockets of disparity.

And if the box was only heated then you'd have to have outside air of less
humidity to replace the "humid" air inside. The key here is a "change of
state" which is what dehumidifiers and AC's achieve.

If the wood is giving off moisture, all outside air is of less humidity than
inside air. The key here is the exchange of wetter for dryer, so that the
process can continue.


I'm sure there're engineers who can figure the cost efficiencies but it
sure seems like a slick way of drying faster than air; less messy than
some solutions; capable of handling a fair volume; with simple fast access
for inspection and testing (no bags or surrounding materials). All done
for maybe $200 to $400 one-time for store bought materials.


There is no way of drying faster than air can absorb moisture. That's
because it's the air which dilutes and carries the water away. Whether that
air is dehumidified at great cost and the water drained away, or exhausted
and replaced by air of lower humidity makes no difference to the wood.
That's why a fifty buck humidistat and two muffin fans, with an option on a
light bulb or two makes a dandy kiln.


I'm still building my shop so my hands on experience is nil. However, I'm
building one under the porch next to the shop since I believe Joe to be
the kind of man to know what he's doing.


Well, vicarious experience shows the way to do things if you have somewhere
to get rid of some somewhat smelly air. It's the way the big boys do it.
Exhaust air of relative humidity higher than desired for the point in the
cycle and replace it with dry air. If what you're hinting at in that one
puzzling passage about your location is that you have a high ambient
relative humidity, you can warm that air, which drops the relative humidity,
prior to bringing it into the kiln near the end of the cycle as well. That
way you can dry the wood below the EMC it would naturally assume sitting
outside the kiln environment.

Of course, it'll start to gain that moisture back as soon as you take it
out, anyway, so I'm not sure what you gain by doing so.