Idea Curing Box

[AmaxB]

To control RH I got this little puppy here and will use relay to drive Solenoids (for vents) (Leverhead suggested) and and maybe 1 in duct fan (exhaust) http://www.ebay.com/itm/1-16-DIN-Hu...142?pt=LH_DefaultDomain_0&hash=item2ebf0aaf6e

 

[AmaxB]

I am thinking of wiring the Pid Humidistat this way, rails could be used in-place of the Junction Box for a cleaner look.
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[AmaxB]

This I found to be a very interesting Read... Heat Pump Dehumidification During the Curing of Flue-Cured Tobacco http://www.probec.org/fileuploads/fl120412991164036100RB439.htm

 

[DrBob]

a common home dehumidifier actually is a heat pump. It would do the job well in the early stage of the flue cure cycle. I would suspect that it would work up to 115 degrees off the shelf with a little creative ducting.

 

[AmaxB]

Hi DrBob in their study they got up to 150F. I could see this being done with a home humidifier / dehumidifier by making a few changes to it. I agree with you for off the shelf. The resulting tobacco between the conventional and the heat pump were very close sort of leads to new thought to create a chamber they pretty much tell you what they did to adapt the heat pump and how they ran it..

 

[DrBob]

You could push it a little warmer but you get into high head pressure issues with the compressor. The compressor would not live long. In reality the lions share of the drying is done below 120 anyway. If you want a heat pump that would do the entire cycle it would be cost prohibitive. Not impossible, just spendy.
Heat pumps are really neat machines but they have thier limitations.

 

[johnlee1933]

You could push it a little warmer but you get into high head pressure issues with the compressor. The compressor would not live long. In reality the lions share of the drying is done below 120 anyway. If you want a heat pump that would do the entire cycle it would be cost prohibitive. Not impossible, just spendy.
Heat pumps are really neat machines but they have thier limitations.

Wouldn't Workhorse be a good guy to ask about this? I believe it's his business.

 

[DrBob]

Actually it is my old business. I still work on heat pumps regularily. My bag is geothermal heat pumps and heat reclamation heat pumps. I understand the beasts.

 

[johnlee1933]

Actually it is my old business. I still work on heat pumps regularily. My bag is geothermal heat pumps and heat reclamation heat pumps. I understand the beasts.

OK Good. Here's an off the wall idea. I run baseboard hot water heat as a backup to my wood stove in this house and for hot water. I have it set at 180°F because I like the quick heat up and really hot water for the clothes washer. What if I put an extra circulator on the system and ducted air from my box thru the dehumidifier over the heating coil and back into the box. Humidity control would be by turning the dehumidifier on and off. Heat control would be by controlling the circulator. Fresh air could be a blast gate in the low pressure of the dehumidifier and another blast gate on the high pressure side.

Oil would be my heat source and it's cheaper than electricity. The fan in the dehumidifier would have a separate control indepentant of the heat pump. Plus there would be no fire hazard.

 

[DrBob]

It would work. But is the juice worth the squeeze? It would work very well, the hydronic heat would be very safe but a lot of effort for a small scale flue curing operation. 180 degree water may not be enough for the final step. 200 might do it.
The plumbing, circulation pump, fan coil, and controller would get spendy. It would be a neat machine and fun to build.

If we were curing a ton at a time your idea has a lot of merit.