Hi fellow hobby growers.
I came across a problem while building a cabinet a while ago when the owner of the cabinet wasn't willing to let me drill big exhaust/intake holes for ventilation equipment.
I heard about some people who had built AC:s (or heat pumps for heating small sheds and equal) out of cheapo dehumidifier internals.

I had bought one for a larger growroom once and don't need it anymore so I thought I'd take it apart and look how its built up.


The design is really simple. Its built exactly like a portable AC only with smaller parts and the condenser and vaporizer aren't separated and equipped with a fan each.

This is what I started with


With just the front and back covers removed it looks like this:


I removed the fand and fan cover to get a better look at the heatsinks.





I'm replacing the hygrostat that was mounted on the front cover with a digital day/night thermostat.




The slightly bluish one is the one that gets cold if you don't want to test which one gets cold yourself.



CAREFULLY bending the warm side upward will help me place it on top of the upper shelf keeping the cold side and compressor inside the grow area.




This is what my test rig looks like right now:


Equipped with 4x120mm 12V fans it holds the cabinet equipped with a 210W Lohius CFL bulb at around 10F lower than room temperature!
I'll test it out with a 400w HPS when I'm done testing this setup.

So it's still just a PROOF OF CONCEPT but it has crazy potential. And no, I did't need to empty the system or use any tools but a copper pipe bender and a screwdriver.

The next thing to do is to remove the rest of the plastic housing and make small ducts for the fans. This will make the performance and size optimal and usable.

[Barnt]

Wow thats cool. How much power is that thing rated to use? Do you notice any change of humidity? Do you get much water condensing on the coils?

[bounty29]

Interesting stuff, should work if you get the airflow set up properly. Dehumidifiers and ACs are the same thing for the most part, just different airflow and placement. Definitely looking forward to seeing the potential of this kind of thing. Nice work!

Originally Posted by Barnt

Wow thats cool. How much power is that thing rated to use? Do you notice any change of humidity? Do you get much water condensing on the coils?

The compressor is rated at 240W if I remember correctly. The humidity will drop a bit but I thought I'd just add an ultraphonic fogger to raise it right up again. The dehumidifier is rated to pull 2½ gallons of water out of the air every 24h.. It sounds alot but in practice you keep the humidity up with pretty easy tricks in such a small, sealed enviroment.

It'll need some kind of simple co2-addition too but I'll try to keep it simple and cheap this time and not over do it like I always do.

[Able Mind]

interesting approach!

[raygun]

Tagged! this is cool if it can work with that 400 and cool the temps 10 degrees.

[FreezerBoy]

Excellant contribution. Rep points for you.

You may want to include a pipe bender write up. I can see people folding the tubing shut pretty easily. Personally, I've packed tubes with sand to prevent crimping but, only when tubing is loose and open at both ends. Wouldn't want to see sand getting into this. Again, nice stuff.

Thanks alot for the positive feedback! It keeps me going.

I've been doing a few modifications today and the thing is getting better every hour.

The upper coil was a pain in the ass to get up on the shelf it's supposed to be on when I start growing. It wasn't a removable shelf and the whole cab is glued and screwed to the wall behind it and on the left side of it.

After hours with my sweetest friend mr. Crowbar I got the sucker up there.




Still not even a hole from a screw in the whole cab!

It's getting smaller and cleaner now.. I removed a bunch of unnecessary (spelling?) electronic crap from the compressor and now only have a overheat protection, the defrost function and the new thermostat on it.




I'll wire up the 400w today (clock's 6 PM here) if I get this baby wired up.

And it's officially beta v.0.1.0 now too (instead of 0.0.1)

[bounty29]

Looking great, this is something a lot of people could find useful, thanks for the documentation.

Starting to look more like a grow cab and not just a empty space with a compressor in one corner..


There's just too much left to do before I can do a test run so I'll continue tomorrow.. even though I won't be able to sleep tonight because of this project