Derek,
When the dehumidifier is enclosed the heat it generates as a part of the
dehumidification process is recirculated. That might answer one of your
thoughts. Remember, only the drain hose and power cord are outside.

Also, I emphasized a basement model because it's specifically designed to
continue to dehumidify at lower temps. And, here in central North Carolina,
31% is exactly what I have now in my living quarters but wouldn't want to
circulate the airborne dust of my workshop through my regular HVAC. Outside
it's 66% at the moment. We may not be tropical but this is not a dry area.

TomNie

"Derek Andrews" wrote in message
...
Tom Nie wrote:
Build a rectangular plywood box, well sealed and insulated with that hard
foam stuff at Home Depot, with a long side facing you and hinged to open
upward for loading. Include shelves that allow air circulation. Install a
dehumidifier (mine from Grainger's - BASEMENT variety) with drain tube to
a bucket outside (to monitor rate of drying). It's plugged into a simple
programmable timer (to control rate of dehumidification better than just
the control on some dehumidifiers). He even uses a small squirrel-cage
fan for interior circulation.

I use a dehumidifier in my drying room, but only in summer when the
natural humidity is high in my climate. There are two reasons for this.

First, the relative humidity I am aiming for (35%-40%) is easily achieved
in winter by modest heating. I just checked and it was down to 31% at only
21C/70F, so I turned the heat down.

Second, my dehumidifier has a chart of humidity-temperature conditions
below which it should not be operated since it may frost up and not remove
water. I also suspect that close to these conditions it will be operating
inefficiently.

To achieve 40% RH, the recommended minimum temperature is 27C / 80F.
Easily done in summer, but in winter will rquire quite a bit of heat.

Having said all that, I am working in a whole room, 7'x8', with two
outside walls, so situation is somewhat different. I also air dry wood
before it goes into this room, and have a continuous in/out process rather
than the batch process suggested. But would encourage anyone setting up a
drying system to consider how they plan to operate it, and whether the RH
can best be controlled by applying heat or removing moisture.

--
Derek Andrews, woodturner

http://www.seafoamwoodturning.com
http://chipshop.blogspot.com - a blog for my customers
http://www.seafoamwoodturning.com/TheToolrest/ - a blog for woodturners