Small Kiln for Turning Blanks

Sort of neat, if you think of it. The heat is produced as a by-product of the refrigeration system which cools the air enclosed in the same box to condense the moisture . I think I'd plumb things differently.

Perhaps that's why the commercial folks exhaust the wet air, replacing with the dryer outside air which, as we know, is free. If they warm the outside air on its way in, they lower its RH to speed drying, and the AH to allow more moisture to be carried away.

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.

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).

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.

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.

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.

TomNie - top posting as usual:)

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.

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.

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.

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.

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.

Ralph, Where are you getting the SunLight LDD. I have seen it before.....and was sure I could find it but so far I have not. I am in the southern part of Indiana. I am a refrigeration technician and spend a lot of time in stores but havn't found it yet. Thanks in advance. Lyndell