My little Peltier fermentation chamber.

[Bob-MTL]

Good day folks!

I know this forum as lots of "Peltier = fails" comment, but then I wanted to show you my fermentation chamber that use theses littles chips.

The basic is to use 4 Peltiers and two water cooling system (one for hot side, other for hot side) to get enough power to cool down your wort. The carboy sits in a bucket filled with cooled water and so it stays cool at the given temperature.

I live in Canada where in summer time, we can get a few hot days, going up to 35 or so, but the average is about 20~25, and the fermenter did work very well so far at that kind of temperature. It's not working 100% of the time, and some tests I made with 10 litres shows it can go down to at least 7c (I did stop the test as I intend to only do ales, which is more than enough for that).

A little note should be said about the price... Because I had to buy every piece, this little wood box did cost me about 200$ (Can), which can be a bugger, mostly when a Brewjacket can be purchased for about the same price, but with a warranty and professionnal look. Then again, this is 100% DIY homemade and I'm proud of my little new toy.

A video showing the device:

 

[NSMikeD]

nice, how is it working?

I use ice bottles with the peltier providing back up - 2 x 5A with hot/cold side fans. My goal was the ice bottles to do most of the cooling and the peltiers would kick on if the temp rose above 68°F (off at 65°). I change the bottles at night and in the morning. This was working great for several weeks - I brew 2.5 gallon batches, so my box can hold one fermentation bucket and 2 torpedo kegs. Right now I have just the fermenting bucket and I am finding the temp rising above 68°F - 72° this mooning before I swapped the ice bottles. I use ambient temp as my guideline.

Thus I have been considering modifying the peltiers to water cool - like yours as I think that is more efficient.


At 10 Amps (you must be at 20Amps) that is a lot of electricity to be the sole source of heat removal.

 

[Bob-MTL]

Hi NSMikeD,

yeah, this is 20 amps or so, but it's 12v, so it's like 2 amps of 120v (a bit more because it's not 100% efficient).

My system uses 3 water cooling heatsink that looks like this one:

(hope the link works)

Two goes for the hot side, and the middle one goes for the cold.

Heatsink - hot peltier / cold peltier - Heatsink - cold peltier / hot peltier - Heatsink.

The most important part is the cooling of the "hot" part. See, for my setup, I use 3 radiators cooled with PC fans and it can keep the temperature about 10c (~20f) degree above the ambiant. So if my appartement goes to about 30 (86f), the hot water will be at about 40 (100) ish. This means the cold side is not "that" cold, maybe in the range of 10-15 (50-60). Today, it was pretty hot, 30ish (86) and the system was still able to keep a good 16c (60) all day.

A few things to consider. The hot side cannot go below the ambiant temperature of your installation, unless you do cool it (?), and so this system is not good for thoses living in a hot spot. By hot, I mean above 25 (80f).

Also, you need the right power supply and the right wires. My previous mistakes was to use thin wires and they were very hot (lucky for my, they didn't melt or cause fire).

Even with 4 peltiers, cooling the water is a slow process. You need to keep it going all day long and you can expect to lose about 1c (~2f) per hour. But since homebrewing take place in about 2-3 weeks, it's no big deal. Once at the given temp, it should be able to keep it easily. A good cooling of the wort after the boil is a must to get the thing going faster.

Insulation! As said, this is a slow cooling process, because it doesn't use that much cooling power (remember that a peltier efficiency is about 20%), so the more insulation you put, the better. In your post, you say that the 2 peltiers weren't able to keep the temp, well maybe your problem comes from some cool leaking (if that's a term).

In your system, I understand that you try to cool down air. Now I did try and found out that it is really hard to manage all the insulation leaks. remember that cooling air is like trying to remove air pressure. If you have any leak, the pressure will simply goes through the holes and you wont go anywhere. Besides, remember that the heat exchange from air to water is a lot less efficient than water to water. I don't know if you ever saw that trick, were you put a warm bottle of wine in ice water and it's cold in like 5 minutes. Putting that same bottle in your fridge would takes hours. That said, I'm not saying it can't be done.

So hope this answers a few questions and feel free to ask if needs be.