Author Topic: DIY kiln question for smart people (I'm disqualfd) (Read 5683 times)

oldsaw · « **on:** March 13, 2004, 06:04:57 am »

Driving to work yesterday, I was struck by a sure sign of spring...my first garage sale sign. Immediately I had flashbacks to last summer when I came across an inordinate number of really old crappy window AC units.

Anyway, yesterday, it struck me that it should be possible to build a kiln around one of these things as a temporary/portable setup. I've seen DIY projects based on dehumidifiers and light bulbs or small heaters, but this seems like an "all in one solution". You've got a lot of heat and DH capability by building some sort of simple heat (cold) exchanger to monitor drying. Just throwing ideas out to the smarter people out there.

Any thoughts?

Frank_Pender · « **Reply #1 on:** March 13, 2004, 06:11:50 am »

Your last sentence leaves me out, sorry.

DanG · « **Reply #2 on:** March 13, 2004, 07:56:06 am »

I must disagree on one point, Oldsaw. You gotta be smart, 'cause you're thinkin' just like me!

You're also cheep!

I think it will work, but obviously not as well as a unit that is designed for the purpose. The biggest argument I've been able to find against it, is that the acids will eat it up. That's not a big concern to me, 'cause I can get them so cheap. I think some "creative" ductwork might be in order, to take advantage of the cold air vs. hot air that is generated. The cold air could be blown through some kind of exchanger to enhance the moisture removal properties.

I have an old unit on hand that works well, so I think I'll try it. It will be interesting and educational enough to make the little project worthwhile. I'm thinking small, here, maybe 200-300bf, to start with.

shopteacher · « **Reply #3 on:** March 13, 2004, 12:21:25 pm »

Butch and I would have tried to respond, but due to restrictions beyond our control, found neither of us to be qualified.

karl · « **Reply #4 on:** March 13, 2004, 02:43:14 pm »

I know you asked for smart people- but I'm posting anyway

My first "Kiln" was a house dehumidifier, a box fan, electric milkhouse heater, 6 mil poly draped over 2x4s on sawhorses in my shop- good thing the lumber wasn't valuable or a large amount, but it worked. I've heard that air conditioners/home dehumidfiers won't last because of the acids too, it's prob'ly just a rumor started by those kiln manufacturers

.
I like my old Nyle 150 hotrodded to 2 hp.
Maybe this is the push I need to try to post pics.. :-/

Den Socling · « **Reply #5 on:** March 13, 2004, 03:15:55 pm »

I think Woodhaven's post sounded pretty good. If Don replies, I think he'll say something about room air conditioners problems when run at 'high' temperature.

Buzz-sawyer · « **Reply #6 on:** March 13, 2004, 03:52:48 pm »

This is an exerpt from an article By Andy Davenport

....... The heart of the equipment is an old 18,000 btu , 220 v window Air Conditioner. ( Gibson, I think....I dunno...I tore all the sheet metal and face plastic off ! ) The AC unit sit on a shelf in one corner of the inside of the kiln. Also use a small ( like 18" ) portable fan on sitting on the floor on the other end to help keep air moving and a small ( 1500 watt ) portable electric heater . I got the AC for free to haul off ( many people here convert to central air....there are a ton of these old dogs around ) , paid about $50 for the fan new ( Home Depot....Lifetime warranty....snicker/snicker ) and the little heater was garage sale $5. Beats EBAC at 20x that !
Running the Kiln
To run it, I load the kiln with 800 to 1000 bd ft of air dried lumber ( I've never tried green....I'm too cheap to spend the electric to do what nature will if you just wait a while ! ) The stack is on 6x6 sleepers on the floor, then stickers as a normal drying pile. I turn on the electric heater to start the room....after the room hits about 90 degrees ( like a day or so depending on startup temp ) , cut it off...the waste heat off the AC is plenty of heat. Start the AC at the same time, when the temp gets high enough, the AC thermostat will kick the compressor in, and you are in the dry kiln business. The waste heat off the AC will continue to build room temp over several days.....mine peaks at about 125. At 100 or so degrees, the water really starts coming off the wood and the room hits 100% relative humidity. This warm, humid air hits the cold coil on the AC and the drip pan fills and in my case, runs into a 5 gallon bucket underneath the shelf. It is hard to believe that it will pull 5 gallons a day off "dry" lumber ! ( YES...a real "engineer" would screw a fitting in the bottom of the drip pan and lead a hose outside, but I like the sauna and like to go in a pet my wood ! ) ( + so much to do...so little time ! )
Takes about 2-3 weeks for a 1000 bd ft load and runs about $50 in extra electricity here.....like a nickle a foot ! HOME DEPOT.....red oak is 1x12 at $6.60 a running foot..HA ! I figure I've got about $0.60 a foot in mine !
Now the question almost everybody asks: YES, the air conditioner is completely INSIDE the room..not a hole in the kiln wall....you WANT the waste heat inside....it is a LOT more than the cold that is coming off the evaporator ( cold )coil....don't think about it....just do it !
Mixing species in the same load seems to have no effect on drying time or anything......
Total costs for the kiln including construction of room, wiring, etc.....about $500 ( and WAY more than paid for on the first load...commercial kilns around here charge $0.50/ft IF they will even fool with your little bit )

A/C Unit - Important Note
Note about the AC unit: The first one tried was an old one a friend gave me...worked fine until the compressor mount gave way and vibrated a hole in it. The next one was also a freebie, but would only work for a short while when the temp got up in the 110 range before the internal thermal switch on the compressor would kick out, the compressor would cool a bit and then kick back in, run 5 minutes, kick out and so on....the problem was the R-22 gas in the last unit. If you get one with R-22, the pressure gets too high much past 100 degrees....they just weren't meant to operate in that range according to a refrigeration buddy of mine. He took out the 22 and replaced it with R-12 that will operate at a LOT less pressure ( and therefore load on the compressor ) in the same temp range. Works like a charm. So get a unit with R-12 or plan on getting it changed over. And I think the old, ineffecient AC dogs are better than a new one.....more waste heat and you want that.

oldsaw · « **Reply #7 on:** March 13, 2004, 05:25:34 pm »

So this could be really simple to moderately complex. I can handle that.

My first thought was to put the whole unit inside and vent out the cold air. Then the acid thing started getting to me, which brought up the heat exchanger thing, then it started getting more complex from there. I had an idea that I was making this a lot harder than it had to be. That still seems like a plan, (I really hate it when the first simple idea is good and I have to try to make it harder for myself).

The auxiliary heater is a good idea. I bought two box fans last summer, one for a quasi-kiln idea (forced air drying, to fight the chance of molding more than anything), and the other for a paint booth thingie. (Cardboard, fan, furnace filter, and TV swivel platform).

I really like you guys, you appeal to my cheaper side. Woodhaven, I may bounce a couple of other ideas off of you down the road. Now I have to start searching for an old AC unit.

Anyway, the thinking was walls and top made of plywood, 2x4s insulation, and inside just a poly sheet (or styrofoam). Put 3-4 T-nuts on each corner. I've got some shingles for the roof, a basic floor, and I've got something I can knock down and store in the garage.

Wife's calling, gotta go. Thanks again guys.

Fla._Deadheader · « **Reply #8 on:** March 13, 2004, 05:30:14 pm »

OK, this sounds pretty good. Can you set the pitch, in Pine, at 160° for 12 hours or so, and how??? Just add more heat, once the low MC is attained???

Fla._Deadheader · « **Reply #9 on:** March 13, 2004, 05:46:14 pm »

I been looking for that equation for years. Thanks, Richard

shopteacher · « **Reply #10 on:** March 13, 2004, 06:27:56 pm »

Woodhaven that is one good synopsis and very understandable. Cold =absense of heat.
What would the consequences of changing the R22 to R12 as far as the compressor is concerned? Could the new 134A be substituted?

Fla._Deadheader · « **Reply #11 on:** March 13, 2004, 06:35:31 pm »

There's a source for 25' Reefer boxes, down here, for $350.00. IF that includes the refrigeration unit, could a plenum be constructed over the exhausted hot air from the coils, and be blown right back into the box??? Seems as that is what Woodhaven is saying??? Have I got this right??? Sure would be an easy install for a kiln, until I get the vac unit working???

oldsaw · « **Reply #12 on:** March 13, 2004, 06:40:55 pm »

Yep, I understand the physics part of heat. Explain that one to my wife all the time. We had a heat spell a couple of years ago where it was above 100 for days on end. The AC unit just couldn't keep up. She got really mad when I told her about removing heat rather than making cold. Thought I was making it up. Then I told her there really scientifically was no such thing as cold, only a situation with less heat. BTW, I was forgetting about the dry air part going back in.

Okay, it doesn't get much simpler than just putting the thing in the box, and drain the water. Just, that's too simple for me, I'm not sure if I can handle it. May just have to mod the unit...need complexity, must have complexity...

This is getting to be a really good thread. A resource for cheapskates for years to come.

shopteacher · « **Reply #13 on:** March 13, 2004, 07:11:32 pm »

How warm does it usually get inside the kiln on a day to day basis? Just wondering because of the talk of it being to warm inside for the AC. I mean in areas like Phoenix it get above 100 deg. on a daily basis and they run the AC constantly, right? Just wondering. Also I've heard the acid in some species will consume the aluminum fins of the evaporator. What do the factory kilns do to avoid this problem, if it is a problem.

Buzz-sawyer · « **Reply #14 on:** March 13, 2004, 07:16:09 pm »

Harold....that would work...dry low humidty air and heat...for 350

DanG · « **Reply #15 on:** March 13, 2004, 09:32:39 pm »

Thanks for the confirmation and the tutorial, Woodhaven.

That's pretty much what Mr Hootie's SIL, the refrigeration guy, was telling me, last week.

Some of the older, high-end, units had a lever that enabled you to either recycle the inside air, or exhaust the room air. Would it make a difference in a closed system, like this?

Now, instead of removing the housing, I was thinking of using ductwork to direct the flow of air, to take advantage of the different outputs. The hot air from the condensor would be blown directly through the lumber stack, obviously. The output from the "cold air" vanes, would be ducted through a series of pipes, which would trap a certain amount of moisture on their surfaces, before being directed back into the intake filter. Do you think I would get enough of a "double whammy" on the DH level to make this extra step worthwhile?

FDH, you could install a heat exchanger to bring the temp up to sap-setting, bug-killing levels with a boiler unit. Just run the same chamber as a "conventional" kiln for a few hours after the wood is dry.

Ianab · « **Reply #16 on:** March 13, 2004, 10:48:34 pm »

Dang.. I think thats overly complicated

What the unit should have is 2 'radiators', one will get hot, one will get cold. (or is that 'get less hot')
What it seems you need is the humid air to be sucked into the cold radiator, the water will condense on the cold surface and run down to a drain or bucket or whatever. The now cooled dried air is blown out thru the hot radiator so it comes out as warm dry air. Blow that thru the wood stack and it should come out humid again...
repeat as required

It all seems practical, knowing there are problems with corrosion, it wont be fast, and there will be all sorts of unexpected gremlins. But just cos people say it wont work is no reason not to do it

Good Luck

Ian

shopteacher · « **Reply #17 on:** March 14, 2004, 02:53:26 am »

Woodhaven: Would it be better to start out with a separate unit like that in a reach-in cooler like in the convenience store? The kind of cooler you get milk or soda out of. The units are already separated and I believe use the lower pressure R12. The evaporator also has a separate fan to move air through the coil and the condensing units usually have adjustable high and low pressure controls as part of the unit.

Fla._Deadheader · « **Reply #18 on:** March 14, 2004, 05:51:58 am »

I know where there is a "walk-in" cooler, that HAS to be moved. The Highway Dept. is widening the road, and will CRUSH it and haul it away?

?

I'm looking at 6 acres, also. Hmmmmmmmmmmmmm

Thanks, Richard. You put out a BUNCH of good info. Really appreciate it.

Fla._Deadheader · « **Reply #19 on:** March 14, 2004, 05:56:29 am »

Also, I been thinkin about using 6" Galv. duct pipe, with them in-line fans inside the pipe. Being as how yer blowin dry air into the stack, that should help "Boost" the air along the length of the duct, for even distribution, EH

shopteacher · « **Reply #20 on:** March 14, 2004, 05:59:13 am »

All Right, now were cooking with gas, or maybe freon.

Thanks Rich.
Harold, what highyway is that along? Just want to put up some flag so no one runs into it and gets hurt.

shopteacher · « **Reply #21 on:** March 14, 2004, 11:37:22 am »

I'll have to start scouting around for an old cooler. Rich, what size box will this require for, lets say, a 2 hp unit?
I still plan to build a vac kiln, but need something I can use till a suitable chamber turns up.

shopteacher · « **Reply #22 on:** March 14, 2004, 03:30:14 pm »

Ya Rich, that'd be pretty hard to hide from the tax man.

WoodChucker · « **Reply #23 on:** March 14, 2004, 03:33:11 pm »

woodhaven, so would there be any advantage in using a dehumidifier to begin with, or does an AC actually work better if it's hooked up correctly ? Thanks!

Oh and I'm talking about one of those small home dehumidifier units.

R.T.

Frank_Pender · « **Reply #24 on:** March 14, 2004, 04:52:34 pm »

Wow, can I relate to all this information. I just went ahead and done the whole thing and it does work. Ingredients: 1 Taylor hotwater furnace, 1 eback 800, 1, heat exchanger 30" square, 1 24' refer trailer with electicity added along with tempm gages for furnace and Ebac, and finally 6 24" box fans.

Results, dried lumber down to 6 and 7 %

Ianab · « **Reply #25 on:** March 14, 2004, 05:08:39 pm »

Woodchucker

A domestic dehumidifier will work for a small scale drying setup, in a diagram like Woodhaven has just drawn. But it doesn't put out much heat or remove a lot of water.
My setup looks a lot like the above picture with a portable dehumidifier and some fans to move air through the stack. It will dry pine and cypress much better than air drying as our local climate is very humid and you can almost watch the stain growing on pine left outside. I might have 3-400 bf in my stack at one time. I look on it as 'controlled air drying' rather than kiln drying. The softwoods dont seem to have the corrosive properties that people talk about with Oak.
By using a larger air-con unit you would be able to dry more timber faster?

Ian

shopteacher · « **Reply #26 on:** March 14, 2004, 05:17:17 pm »

I likes it Rich, I likes it.

Now all I gots to do is ta build it.

How's that movie go: Build it and they will come
I guess in this one it's: Build it and they will dehydrate.

DR_Buck · « **Reply #27 on:** March 14, 2004, 05:44:10 pm »

Let me complicate this a little bit.......

What if you combined one of these dehumidifier designs with a solar kiln?
1. Will it work?
2. Will you gain any efficiency by doing this?
3. Is it worth trying?

WoodChucker · « **Reply #28 on:** March 14, 2004, 10:09:41 pm »

Ianab, thanks for your answer and taking the time to make it clear enough for me to understand. As you can tell by my question, I don't know anything about heating and AC, at all.

I don't have an old AC, but I do have an old DH that I thought maybe I could put to use. But from your answer, I guess I won't bother with it. Thanks again for your help!

woodhaven, I guess I didn't have enough information in my question for you to figure out what I was asking. But thanks anyway for at least taking the the time to reply to my post and not just ignore me. Appreciate the input!

R.T.

J_T · « **Reply #29 on:** March 17, 2004, 05:59:28 pm »

Thanks Woodhaven I got acompressor says it will pump R12 R22 or R502 may try that blue print someday.Guess all I got to check is expanshon valve and weld it together.

IMERC · « **Reply #30 on:** March 18, 2004, 12:45:03 am »

Oldsaw...
Yur smarts level just went up... I'm here to make you look good.
2 years ago I decided that I needed a kiln. No www.kiln.com was available to me then....
So on the logic that I want to REMOVE water I built a box from salvaged 8" thick VB'd foam board (R70) at the ID demensions of 20x4.25x8.25'. Put in some sleepers, stickered the lumber threw a 3T commercial dehumidifier at it... (one of those it found me things). Good to go. 2 weeks latter dryer lumber. 3 or so weeks - BINGO!!!
Never tried green. Always air or kiln dried stuff.. I wanted 5% but would settle for 7 to 9%. (I can get in a hurry some times) Latter I found out that I needed to add heat. Okay. Add one found electric overkill sized heater and immediately get worried about having built an oven and not a kiln... Time now for some temp probes. WOW! 190 degrees... This can't be good... Fiddle with the thermostat and get 125/30... This rocks, I thinks... Change the resistive coil heater latter on to 2 oiled filled ones that look like radiators... Much gooder... We're on a roll...
Now I find I need a fan(s) and higher temps... Being a uniformed dummy was bliss, it was... If I am not mistaken, now I want 140/50 degrees and indirect ventillation. (air movement) Something I didn't get straight in my head is the automatic vents. In the dark there...
So the issues are: could somebody tell me what I want for venting, inside to out... Suggest some ways for the best air flow. Is 140/50 degrees what I really want? What am I doing wrong here that I don't know about or see?
Also I need to increase the size of the box to 30 feet long. I gots the stuff to do it. Thought in terms of a box at 30x8.5x4.25ID. Is a 3T dehumidifier big enough. I do have a pair of 2T-AC's that I can put in it instead or in addition to... One box fan or 3. 3 is all I have. Would it help to reconfigure box size???
Another thing I see all the talk about metal liners. Wazzwiddat??? The VB is currently fiberglass mat reinforced bimitious membrane.... As a side note where is the corrossion that I need to watch out for that has been mentioned??? I haven't seen any anywhere's...
The hard part is that I never spent a dime on it till I lit it up... My wood drying is for projects that I work on. I doubt that I have ever dried more than 500BF at one time. With real small batches, 1/200BF... I partion the box size down unless material lenghts say I can't....
Honest... Nobody never told me this wouldn't work. So it did sortta...

Den Socling · « **Reply #31 on:** March 18, 2004, 04:27:36 am »

IMERC,

As long as you are finishing predried wood, there is not much damage that can be done. If you started with green wood, things get more difficult. If you didn't have enough air flow, you might get mold. If you didn't vent enough, you might not do any drying. If you got too warm, you would get a bunch of cracks. If you got it all wrong,

you might end up with honeycomb (which ain't too sweet

).

Den

IMERC · « **Reply #32 on:** March 18, 2004, 08:56:06 am »

Guys
I can down size to a 1T dehumidifier and add airflow. What about venting and box temp?
I have an up coming project that I will need to dry Hickory. (9K-BF) to less than 10% before I start.Then I'm back to the small stuff... The longer box is because of material lenghts.
I would like to get this right.

IMERC · « **Reply #33 on:** March 18, 2004, 07:58:20 pm »

Woodhaven.
I Can reconfigure the box to most any size. Those panels are 5x10'. I used splines to fabricate what I have and everything is put to gether like Leggoes.
The internal temp is thermostaticly controlled.
How much of an exhaust fan.. I take it the fan acts as a cooling unit to cap the higher chamber temps..
Okay I will give it all a try

IMERC · « **Reply #34 on:** April 14, 2004, 07:25:00 am »

Anyone
I built the larger box and put in the 1T DH unit in the near geometric center, 2 fans -1 at the end of the material and 1 at the center moving the air length wise and I can't seem to get below 12% as of this morning. This klin dried Hickory went in at about 16% a month ago. Box temp is holding at around 140/145*.
Am I being impatient or have I not got something right?

Den Socling · « **Reply #35 on:** April 14, 2004, 02:39:24 pm »

My first guess would be that you need another 10 or 20 degrees to get a reasonable drying rate.

IMERC · « **Reply #36 on:** April 14, 2004, 02:47:49 pm »

That I can do.
What would be the threshhold of too warm / hot???

Den Socling · « **Reply #37 on:** April 14, 2004, 03:24:41 pm »

In a conventional kiln, with 4/4 hickory, with the core under 15%, you might be pushing 160 - 180. If it's really 12%, you aren't going to hurt it with heat.

IMERC · « **Reply #38 on:** April 14, 2004, 06:53:06 pm »

Den
When I put it in the kiln and the MC came down a couple of points I should have rasied the heat then to 160 / 180?
This Hickory is 2S1E at a nominal 13/16" (3/4) w/ waxed ends.
What are the warning signs of excessive heat.
I'll fiddle with the temp and go for 170/175*. The heat at this time is 150/155 per yur earlier suggestion.
Was the drying process at idle or was it just going to take a month of Sundays?

IMERC · « **Reply #39 on:** May 07, 2004, 02:09:56 pm »

Den
I took some the Hickory out of the klin and it measured 6/7% MC on the average...
So yur valued input worked... Thanks....

One question though.. The wood appears to have substancially darkened. Some Oak I had in there did the same. Is this normal? Where the stickers were stayed a ligher tone / color. Did I in effect burn the wood???
I have the temp set for 165/170* and the highest I saw it get to was 185. Now I see the need for automatic vents....

One more thing to do....

Den Socling · « **Reply #40 on:** May 07, 2004, 03:28:23 pm »

Time and temperature does affect color. On the good side, sapwood is often darkened and will blend in without being noticed. On the bad side, high temperature dulls and darkens.

I'm in the middle of an experiment to find the minimum temperature and time that it takes to color sapwood in Cherry and Red Oak. Hopefully, it's not necessary to dull the bright colors.

logosoluser · « **Reply #41 on:** February 11, 2005, 10:32:52 am »

OK, I have a question or two concerning this issue with the AC for a kiln. Does the AC have to actually make cold air? I have an old unit that cools a little, but not enough to make it worth using in the house. I know the compressor still works on it, so I was wondering if thats all you needed anyway was the compressor taking the moisture out of the air. I am not very knowledge about anything along these lines, so I need real simple detailed information about this operation. I think it might be something that will work good for me.

Buzz-sawyer · « **Reply #42 on:** February 11, 2005, 10:52:49 am »

Try the 6th post on this thread

It has to still be able to condense vapor....It HAS to cool,

UrbanLogger · « **Reply #43 on:** February 11, 2005, 10:55:12 am »

The compressor takes moisture out of the air by compressing the coolant, which makes the coils cold which condenses moisture out of the air--no cold, no condensing.

GaS · « **Reply #44 on:** February 12, 2005, 01:01:46 am »

Assuming the compressor is charged and operates correctly, perhaps the filter and/or fins need cleaned? A friend of mine had an A/C he was gonna junk. I said 'don't throw it out, l'll take it'...well it sat in his garage for a while till push came to shove and it was time to throw it out. I said 'all I was gonna do is check the filter and coils'...sure enough, it had never been cleaned and the gentle waft of cool air became a blast of cold air.

Worth a shot on those old house units!

Tn...Andy · « **Reply #45 on:** February 21, 2005, 08:20:06 pm »

Hey Buzz-Sawyer....

Where ever did you find that article ?
I haven't seen it in years.......

andy

Ironwood · « **Reply #46 on:** February 26, 2005, 07:23:30 am »

I did not read all the threads but heres my experience,. I know several people here in Pa that run large used commercial AC units to pull the moisture out of their kilns. They work very well. These folks monitor the kilns closely and have learned the details of wet bulb, dry bulb, and all the RH/ heat stuff (lots to keep track of). I bought a premade unit to avoid all the control/ monitoring issues they deal with. The DH kilns are simple in and of themselves to me it is the control units Nyle/ Ebac and the others provide that make it worth the money. It just depends on how much time you want to spend teaching yourself/ working out the bugs of your particular set up and then how closely do you want to monitor it. REID

old3dogg · « **Reply #47 on:** February 26, 2005, 08:31:01 am »

I agree Reid.
All dry kilns are only as good as the people who operate them.

woodhaven · « **Reply #48 on:** February 26, 2005, 04:08:48 pm »

There is no such thing as (make cold air). What you have is air that the heat has been removed from.
You may say what is the differance. Well when trying to understand this stuff there is a BIG differance.

4woody · « **Reply #49 on:** January 03, 2007, 08:08:25 pm »

has any else made a kiln like this

kelLOGg · « **Reply #50 on:** January 15, 2007, 02:40:06 pm »

I've been following this thread for several weeks learning all I can. Now I am now putting together a tarp-covered rack in the 2nd floor of my barn for DH drying of small batches. I have a 1 year old window A/C unit we had to install in our home in an emergency last summer and now it is available for my wood drying efforts. The only problem is that I never saw condensate dripping from the unit. Is it possible that newly manufactured window units put the condensate into the warm exhaust to avoid dripping water? If so, that would render the unit completely useless for wood drying. What were they thinking?

Can anyone verify that some modern window units are dripless?

Concerning sizing of the operation - I want to dry 700 - 1000 BF from ~20% to ~7%. The unit I have is 125 VAC, 5.5 amps, 6000 BTUs/HR. Ignoring the dripless problem is this a reasonable size unit for the job?
Bob

beenthere · « **Reply #51 on:** January 15, 2007, 03:27:24 pm »

Can you tell us what the temperature is and what the RH is at that temperature (at which you are trying to get the water to condense off the AC unit) ??

kelLOGg · « **Reply #52 on:** January 15, 2007, 04:10:22 pm »

Here in piedmont NC the summers are 90+ degrees and 50+% RH daytime and nighttime lows are 70ish and up to 100% RH. All residential A/C and heat pump units I have ever seen in my area drip a steady stream of condensate.

Bob

JimBuis · « **Reply #53 on:** January 15, 2007, 05:18:00 pm »

There are cooling units that use the condensate to cool the condenser. Whether or not that is your situation is hard to tell. Irregardless, you'd need to have the condenser side of that A/C unit vented outside of the conditioned space, so it should not matter if there is condensate dripping or not.

Jim

kelLOGg · « **Reply #54 on:** January 15, 2007, 05:57:39 pm »

you'd need to have the condenser side of that A/C unit vented outside of the conditioned space, so it should not matter if there is condensate dripping or not.

If the condenser side (I assume that means the warm exhaust air) is vented outside I would have no heat added to the lumber, slowing the drying process. So if my unit uses the condensate to cool the condenser AND I want to use the waste heat for warming the lumber I cannot use it. Correct?

PineNut · « **Reply #55 on:** January 15, 2007, 10:31:12 pm »

Some of the window air conditioners have a slinger ring on the fan, which puts the condensate on the condenser. If you wanted to use one like this, you would have to find a way to drain the condensate and keep it away from the condenser coils.

kelLOGg · « **Reply #56 on:** January 16, 2007, 05:25:42 am »

Aha! thanks, Pinenut - sounds like I can remove or disassemble something and get the condensate to drain instead of evaporate. Its worth a try.

JimBuis · « **Reply #57 on:** January 17, 2007, 05:16:41 pm »

Quote from: kelLOGg on January 15, 2007, 05:57:39 pm

If the condenser side (I assume that means the warm exhaust air) is vented outside I would have no heat added to the lumber, slowing the drying process. So if my unit uses the condensate to cool the condenser AND I want to use the waste heat for warming the lumber I cannot use it. Correct?

I am not totally clear on what you are doing, but here goes. If you simply stick a window A/C unit in a room plug it in and drain the condensate out of the room, you will succeed in lowering the moisture content of the room, but the temperature of the room will not increase significantly. The reason being you are dumping almost as much cool air into the space as warm air. The small temperature increase will result from the heat put off by the compressor and fan motor.

To make this work with any hope of efficiency, you'd have to duct the cold air outside the room while still sucking in air from the room to remove the moisture. Anyway, it sounds like you are wanting to use a window A/C unit in place of a dehumidifier. I've never tried it, but I doubt it would work very well.

IMHO,
Jim

kelLOGg · « **Reply #58 on:** January 17, 2007, 08:51:38 pm »

I plan to duct the cold air out of the kiln via metal ducting to help warm it up to ambient temp and duct it back to the kiln as makeup air. I chose an AC unit because I have one and earlier posts in this thread cite usage of AC units for DH drying.

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Author Topic: DIY kiln question for smart people (I'm disqualfd) (Read 5683 times)