Flaviking

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So I am starting to brainstorm for my fermentation chamber. I have already bought and gutted a small Excellence mini Fridge.

I am looking for some help on this as it is my first go round and I am sure you experienced DIY'ers could tell me something I dont know that I don't know.

The plan is to immulate this Kelvinator box fridge. The bottom part will have a drawer that can hold two cases of bottled homebrew, the top portion will be shorter than that (around 34" tall x 35" wide) This should be large enough to hold two 6.5 gallon glass Carboys.



I want to have a two chamber temperature control (I think) using two ebay sc-1000 aquarium temperature controllers. One controller in the bottom chamber controlling the condensor, the second controlling the temp of the fermentation chamber by operating fans connected to the lower unit and pulling air up from the bottom.

Here is my very simple design:



I know pulling air from the bottom is not the best idea, but I am concerned the condesor I have is not long enough to reach the top as its very short., And I am not sure I want to mount it on the upper side of the unit.

The whole thing will be insulated with 2" foam board.

Please let me know if you think this is just a flat out terrible idea, or if you have any ideas you think would work better.

Thanks in advance!

carlisle_bob

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Hi

The gotcha is going to be getting the two STC-1000's to play nice with each other. You want the compressor to be on when the fans are on. The compressor may also be on when the fans are off.

Bob

Flaviking

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Yeah,

I am thinking maybe its best to just use one STC-1000 that controls both the fans and the compressor and locate it in the actual fermentation chamber. That should keep the bottom portion cooler than the top, which is what I want anyways. Kind of a Rich uncle of fermentation chiller approach.

I got the base built yesterday and I am fitting the compressor and heat coils tonight, then hopefully finishing it this weekend or next. Does anyone have any good ideas for how to move the cold air?

What fans work best? I was thinking of getting some insulated HVAC conduit and attaching it from the bottom of the bottom portion to the top of the top portion on the outside, as I have some space in the back to tuck it into. Not sure if this is the best plan though.

carlisle_bob

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Hi

If the gizmo is in an inhabited area, you want quiet fans. Newegg sells a lot of different computer fans pretty cheap. Get some that are rated below 30 dba (20 if you are picky). Fans > 120 mm seem to be the best bet to move enough air quietly.

Power them up off a anything that supplies 12VDC. Any old wall wart that will put out an amp will run far more fans than you will have.

Since the fans are at 12V and the compressor is at 120V, you either will need to run the wall wart off of the switched juice or have an extra relay to switch the other voltage.

You might consider trying a setup where the "upper" controller runs both the fans and the compressor. Let the "lower" controller just run the compressor. With enough fiddling of set points and cut in / cut out's it could be made to work.

If you are planning to vary the temperatures a lot and want accuracy in both chambers, I'd drop the STC's and just get one of the fancier control cards. It'll save a lot of frustration ....

Bob

Flaviking

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Would something like this work?

http://www.ebay.com/itm/100-240V-AC-to-DC-Adapter-Converter-12V-1A-Power-Supply-for-CCTV-System-US-Plug-/200764650737?pt=US_Server_Power_Supplies&hash=item 2ebe8174f1#ht_3539wt_1185

carlisle_bob

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Hi

Looks fine to me. There *might* be another one out there for 50 cents less.... One amp is more than you need, but you can't get much cheaper than the one you found regardless of the current.

Bob

Flaviking

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I actually found a old 12v that was used for a comcast cable modem or something...

So I think I am heading back to the drawing board here.. not really sure what to do.. I was thinking having the cooling coils in the actual fermentation chamber would give me the most accurate temperatures.. and at the end of the day, that is what I am most concerned about.

I want to keep the bottles cool during their bottle conditioning, but fermentation is the top priority ( I can always store the bottles elsewhere),. And I think if I cool the top chamber, it will be much easier to draw air from there into the lower chamber and keep the top chamber at the most accurate temperature.

This way, Ill have the STC-1000 operate both the compressor and the fan and that should keep both chambers at the same temperature.

Flaviking

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Just ordered the STC-1000.. Found one calibrated to Ferenheit...

Man... Saturday can't get here soon enough!!! I want to get building again!!!

carlisle_bob

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Hi

It can be a STC-1000 *or* it can run in F. It can't be both ... Which one did you get?

Bob

Flaviking

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Ha.. So I guess the C in STC stands for Celsius?

I got this one:

http://www.ebay.com/itm/Digital-Temperature-Controller-Thermostat-Aquarium-F-/320926548163?_trksid=p5197.m1992&_trkparms=aid%3D1 11000%26algo%3DREC.CURRENT%26ao%3D1%26asc%3D14%26m eid%3D417770991473846952%26pid%3D100015%26prg%3D10 06%26rk%3D1%26#ht_3947wt_1185