Using Peltier and conical

Afternoon all!

I am about to pull the trigger on a half barrel conical and will not have a walk in chamber to put this guy in. I am thinking of building a peltier block with 4 coolers and just have this sitting in my garage (in Texas). My question is how would the Pi handle ambient as the heating source and does anyone see any issue with a setup like this?


thats interesting. are you going to build the cooler or is there a COTS product you are going to buy and use?

The cooling blocks will be one offs I will have made on a CNC machine. On a side note though these guys might be a good option:

I dont see a problem of using ambient as the heat. I use the ambient temp of my flat as the heat on my fridge setup. It takes a bit longer to heat up than a heater would, but doesnt impact the ability to maintain the set fermentation temperature.

I like the idea but doesn’t this method of cooling create large temperature gradients in the fermenting beer?

I guess when fermentation is going the beer is fairly turbulent so the temperature probably distributes quickly. It just seems strange to have a point source of cooling like that.

If you do not set up a heater in device manager, it will just not go in a heating state.

I have played with peltier elements a bit and the amount of heat they can move is not that much. The efficiency is low and the temperature differential they can generate is limited. I doubt they will be able to offset Texas summer temperatures.

You might have better results by mounting a coil inside the conical and pumping glycol through the coil form a reservoir in a fridge next to the conical. Look at how they do it at SS brewtech:

I’ll have to find the link later. But i recently saw a build on hbt where a guy built a peltier into an igloo drink cooler to control fermentation. He has his setup so that when heating the peltier is wired one way and swapped for cooling so he only has 1 peltier in the mix.

Total waste of your time and money. Peltier is weak and ones that can actually cool properly, are extremely expensive. Go and get yourself a used cooler and a heat lamp/wire from pet store and you are done.
You can start using it by Monday :wink:

My problem is really the size of the fermenter. I had a BevAir Pepsi cooler before in North Carolina and a conical would fit perfect in that and was easy to get in and out since it was front loading. I don’t think a chest freezer will be practical and most vertical freezers I have found have a bump or cool through the shelves which makes modification a bit more complicated.


This is really no different than my morebeer heated/cooled conical. Easily keeps beer 10°F below ambient temps using the ranco. Once I’ve got my current beer out of it I’ll be running a water test using the brewpi.

Probably no good for your Texas garage. But in my IL basement I can still ferment lagers in summer.

Typical cooler with 60 cm depth in EU has plenty of internal depth to fit a 45 cm diameter fermenter comfortably.
Bump at the bottom (for compressor) is no big deal because you can build a shelf from few pieces of plywood. You have a almost 60 l fermenter so this is not that heavy. 60 kg + what ever the fermenter weighs. This can be distributed easily between the floor and the shelf grooves in the wall. (I have a 55 l).
Get a simple Electrolux (or what ever thy are called over there) :slight_smile:

I am planning to build 2 square fermenting vessels that sits in 2 or 3 rows shelf groves.
60x175 cooler can easily be used to ferment 100+ litres. Only show stopper is the cost :slight_smile:

Or use a maxicooler, wired up so that the brewpi controls when the python pump comes on?

Well got the brewpi arduino up and running. Water test right now, no problems maintaining regular ale temp, currently dropping down to lager temps. Sure there will be some tweaking.

@Elco I ended up getting some parts for the FTSs system and have it running now, however I have a question about probe placement.

I have the beer probe in the top thermowell and I have the fridge probe sitting between the neoprene sleeve and the outside of the conical. I am wondering if that is the best placement as I do not see the same level of accuracy I have seen with an actual fridge setup.

Is there any sorta best practice for placement and other software level configurations?


I think that’s the best you can do. When we have PWM support in the next update, you can use a single sensor setup.


I will wait for that. I need to go ahead and get my Spark up and running, but think I may wait a bit more.


I’m currently working on a 3 gallon Peltier-driven cooling vessel that is constructed out of insulation board, two aluminum heat sinks (hot side with fan, cold side passive), an aluminum spacer block and a 24V 120W Peltier tile. Test runs are going well though I’ve been at this for a few months. I’ll post photos once I have the prototype up. As others have mentioned, a large temp differential or large volume of beer is likely too much for the Peltier to handle. That said, many wine refrigerators now use them (that’s where I got my inspiration). Check out the for a concept for 5 gallon batches. A friend of mine tried to cool a conical with Peltiers but had a problem insulating and also matching the curvature of the conical. They eventually just burned out.

@Elco - could you explain a bit more how the PWM would work in this setup? Also, I’m hesitant to drop the beer temp probe into the beer, but I suppose that’s best.

If you want to heat and cool with the Peltiers, you will need a big H-bridge.
You can buy this one on eBay:

You would use 2 outputs for the Spark to drive it and set them up as cooler and heater. You will be able to link them together so they cannot be active at the same time.
The PWM signal would send a pulse every 4 seconds, with the pulse length varying between 0 and 4 seconds.
The PWM signal can be generated from just the beer temp.

I would run the fan continuously.

That’s a good point on the fan - I’ll make sure to run that separately from the Peltier and keep it on. My first pilot will be cooling only but I do hope to add the H-bridge eventually. I’m doing another test run today - I tried stacking two Peltiers and am now going back to the one since stacking seems ill advised. I’ll post photos tonight.

Elco - Would you recommend using a power source for the Peltier that matches the optimum maximum voltage (in my case 12 volts - 50% of max current is most optimal at 6 Amps) or should the power source be higher than this amount if using PWM? My Peltier device is rated up to 24 Volts but will be very inefficient above 12-15 Volts. My initial tests have shown this to be the case as the Peltier produces too much heat at higher Voltage and does not transfer heat efficiently.