theoriginalryan

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I did some test before i got in to it good, what i found is that a peltier system is just not really going to have enough watts of cooling power to cool a actively fermenting brew. I cant remember the exact statistic, but it was something like every .004 of gravity dropped, temp rises 2 F. with the amount of heat (or cold) disipation of 5 gallon of wort in there also, the amount of TEC you would need plus power supply and time invested just wouldnt be worth it. better off just buying an old fridge.

z987k

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This does seem to be the problem with using a peltier device for cooling. It's actually more expensive and more difficult than a fridge.

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Yuri_Rage

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For me, this is abandoned for now. I know it's not without merit, but I don't have the time and resources to devote at the moment. Perhaps I'll revisit at a later date.

For now...I have a fence, deck, and brewhaus to build, a garage to set up, and some ideas for outfitting the brew rig in a new location.

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jameswardpeterson

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The problem with peltiers is that they are incredibly inefficient. (as stated above) they are something like 8 times less efficient than the standard cooling system used in refrigerators and freezers. the best thing to try would probably be to improve the surface area on the heat sinks...

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theoriginalryan

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or just skip it and throw it all in a fridge and save the headache. As some projects go, i think this one might be more of a pain then it worth. Want something cool to do, ive seen a pulse jet engine camp stove(has it own name, just cant remember what it is) that could boil a gallon of water in a minute five seconds. have fun

Ryan

SHvanBommel

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this is kind of old and I hate kicking dead horses some more but... What if you were to make the rod longer (say so long that it sits about 3 inches off the bottom of a carboy) and modified a stopper so the heatsink+TEC could be above the mouth and still have a spot for an airlock... does this make sense?

theoriginalryan

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what you are saying makes sense, but trying to use a TEC to do this just doesn't. you would just be better off hacking up a micro fridge and going from there. TECs just cant put out the watts of cooling that is needed easily.

lamarguy

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I'm joining this party late, but I'm going to have to respectfully disagree.

I've purchased and modified a TEC-based wine cooler to ferment down to ~55F. In stock form, it could go to ~62F, but it took 24hrs. All I did was (1) install a higher amperage TEC, (2) install a higher flow fan, and (3) do a bit of airflow modification on the rear of the unit to better dissipate heat.



So, yes TEC technology is viable. But, it has to be designed correctly.

Also, I'm controlling the heat/cool cycle over a one-wire network connected to a laptop. Works well in the winter and summer and has +-1F accuracy. Overkill, perhaps, but it meets my needs perfectly.

tac0meat

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I really think thermoelectrics can be used for keeping fermentation temps in check. I think they might not be up to the task for lagers, but should work fine for ales.

lamarguy, I have been kicking around a similar idea, scrapping the parts from a wine cooler to keep my fermenter cool. seems like everything one would need is in the box; power supply, thermostat, peltier device, heatsinks, fans. My only problem is that I have been unable to find a wine cooler for less than ~$80 and the ones in that price range seem to have a very limited temperature range.

Here's my take on it:

I picked up this little guy called a PAC400 made by waffer/masscool for $20: Masscool AC-PAC400 PC AC Portable 82W PC Air Conditioner AC-PAC400

its basically a thermoelectric cooler for a computer. a quick google search will yeild many reviews in where it is shown to be inadequate for computer cooling, but does show the ability to drop incoming air temp by a solid 10 degrees F. I think that should be good enough to keep my fermenter from getting too warm, especially during the first 48 hours or so.

my idea was to build a "son of fermentation chiller" style box, but instead of trying to keep it cool with ice, I would mount this PAC400 device in the top, recirculating and cooling the air inside the box.

the most obvious issue would be to power this thing, which requires up to 6-7amps at 12 volts DC. my plan is to use an old atx power supply from a computer laying around for this task.

next thing to tackle would be a thermostat. I found this kit for $9 plus shipping: Thermostat Electronic Kit MK138. it is adjustable from 41F to 86F, perfect range. it uses a small thermistor to determine temperature. I would think it would be pretty easy to extend the leads a few feet to drop inside a thermowell

now to hook this all up:
the ATX power supply supplies plenty of power at 12volts, but wont turn on unless one specifc wire is grounded. the relay on the thermostat should have no porblem completing this task as the turn on current is only a few milliamps.

the thermostat will require 12volts all the time to work, however. the ATX power supply has a constant on 5volt rail. using the plans I found here: LM2577 5V to 12V DC Converter step up Voltage Regulator I should be able to build a 5 volt to 12 volt converter for less than $10. using this, I can take the constant 5volt power, convert it to 12 volts to run the thermostat, when the temperature rises above whatever I set it out, it will switch on the rest of the ATX power supply, providing the 12 volts to the PAC400 cooler. once the temperature drops back to below the setpoint, it will shut off the 12 volt side of the power supply and continue to monitor temperature, turning back on as neccesary.

if I can house the thermostat and voltage converter inside the ATX power supply, I should have a pretty clean setup that should give me good control over fermentation temps. I picked up the PAC400 and have ordered the thermostat. I just need to get the parts for the 5v to 12v converter, so it will still be a week or so before I can start putting it all together. all in all, it should cost a total of about $40, not including the foam board for the box.

lamarguy

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It seems like you've put ample thought into the project.

My only concern would be finding a thermoelectic unit with enough capacity to bring the internal ambient temperature down 20F below the ambient room temperature. The one you posted a link to is woefully insufficient (52w). I've found that you really need a thermoelectric unit in the 80w - 90w range.

Recall that during the first few days of active fermentation, the temperature of the liquid can rise 5F - 10F above ambient air temperature. So, if your house is at 75F and your target liquid temperature is 65F, then the air temperature inside the insulated box needs to be at 55F - 60F.

Personally, I found the most efficient route was to buy a preassembled cooler and thermoelectric unit (such as the Edgestar Wine Cooler) and modify it with an external temperature controller. I went with the wine cooler because the interior dimensions are square (no compressor hump) and I can use the thermoelectric unit for heating/cooling fermenting ales year-round.

I also use an upright frost-free freezer with a Love temperature controller for fermenting lagers, storing grain, etc.

With that said, technically, the most efficient cooling solution would be to circulate a coolant through pipes run inside the fermenter. That would maximize the total energy transfer, but it also creates a lot of headaches to design and build.