# Peltier For Cooling/heating Fermenter



## Baulko Brewer (17/5/11)

I want to pick the brains of you electical geniuses out there or perhaps someone who has achieved something similar:

I am currently using my beer fridge as a place to keep my fermenter to keep temps constant.

I am thinking of devising a cheap alterior method that will allow me to use my fridge for its original design. Keeping the beer cold.

I want build a box and insulate the interior. Easy!! Now the tricky part....

My thoughts are to get one of those STC-1000 thermostat controllers off Ebay and hook it up to two peltiers. One peltier hooked to a copper plate at the bottom for heating and another at the top for cooling. I believe that the thermostat will regulate the temp accordingly. 

Will the peltier offer enough heat/cooling to produce constant brewing temps? I want it range from say 5-25 degrees. The box is going to be roughly 24"W x 24"D x 36"H. The copper plates I considered are 15cms x15cms x 1.2MM

I only remember the peltier by year 9 science and remember it being very hot on one side and extremly cold on the other.

Can I maybe get away with only having 1 plate and both peltier's hooked to the same plate.

Is there a better way (Apart from belt pads etc)??


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## vykuza (17/5/11)

There was some discussion about using peltiers to cool fermentations a few months back I remember reading - but I don't know if it went anywhere.

Using my very crooked rule of thumb, I think it would be quite expensive to buy all the kit you needed to get this working (high current power supply + heatsinks + the peltiers themselves aren't cheap) and a lot of juice to run it in relative terms. 


http://www.aussiehomebrewer.com/forum/inde...showtopic=41406
^^ found it


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## Baulko Brewer (17/5/11)

The idea is to make it cheaply. I can source the peltiers off Ebay for $8 delivered and the STC-1000 for about $25. the copper plate is about $15. My idea is so that I can use it to winter brew an ale or wit and also lager in summer. the cooling is not the issue, but orgainsing so that i can heat and cool depending on temp changes


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## mwd (17/5/11)

I have a Peltier controlled wine fridge that I use up here in the tropics for a fermentation fridge. As far as I am aware it only uses 40W so quite economical to run. It is not very efficient at cooling wort from high temps down to 18C I usually add a couple of ice bottles to aid it along. Once the fv gets to temperature it holds 18C easy with the highest daytime temps here of 30-34C during the summer. 

Be interested to see how you progress with your plans keep us informed if you get it it up and running.


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## mickpc (17/5/11)

I think there is little point in having two peltiers, either you want your beer cooler than ambient or hotter than ambient temp. If it is well insulated then cooling would be the go.


If you do go for two, then have enough of a temp range to ensure that they are not both on at the same time.

Be a good idea for lagers.

Mick


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## Bandito (17/5/11)

You might like to look into high power peltiers used for cooling cpu's in computers - at least for the cooling side. 
I have tried to build a large peltier fermenting fridge, but it didnt work, about 1% the required insulation, how not to do it. I would suggest using an actual fridge or chest freezer at the very least. Perhaps use the built in thermodynamic heat pump that comes with fridges too.


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## mh971 (17/5/11)

Pretty sure these portable cooler/warmers for cars are Peltier devices

http://www.supercheapauto.com.au/online-st...147#Description

This one is the most powerful i've seen with a 30deg temp differential down to 1 degree. i.e. if you had it powered in shed and it was 45 deg then your cooler would be at 15 deg running flatout. But it's only a small box and I expect best at maintaining temp of whatever you put in it rather than cooling or warming stuff.

What you need is the calcs that give you how many kW ( or W) are needed to be applied to a given mass at a given temp to change it's temp by 1 degree, then you'll know how many cells are needed based on cooling output of cells in W to achieve desired cooling. This will let you know if it's likely to be cost effective, I expect not, especially once you mess around with PSU's and other build hardware. 

So far I have been given 3 fridges which cost me nil. and just added temp controllers. Upright Freezers are good too if you carefully bend the colling shelves up towards back of unit.


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## Doogiechap (17/5/11)

Bloke there has been a bit of discussion over the years about the use of peltiers. Here is a link listing a few threads I have commented in previously but also has some good input from others like Hutch who have had more success. Be mindful that peltiers dislike being switched on and off as a form of temp control and will stay alive for longer by varying the voltage that is driving them.
Cheers
Doug


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## mfeighan (18/5/11)

peltiers are dirt cheap, i got a few lying around after some projects. i think they cost a few bucks and free shipping off ebay.
you can source a 120w universal laptop charger to run it, if you look around you can get one for ~ $40, we source ours from brianology.com.au

the downside is they are a very inefficient way of cooling compared to a compressor and your power bill/usage would be significantly higher
i used the peltier to make a peltier cooled beer mug like shown here a bit of fun and then never used


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## Zizzle (18/5/11)

Yeah I don't think they are that great at cooling efficiently from what I have seen.

Just to through in alternative approach, consider putting your insulated fermenting box right next to or on top of your serving fridge. Use the tempcontroller to run a pond pump that circulates cold water from the fridge around your fermenter.


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## Bandito (19/5/11)

The power rating is just the amps x volts. The effiency is always low at best, but it is drastically effected by the temperature difference between the two sides. The higher the temperature difference the less efficient. Best efficiency (perhaps around 50%) is attained with a temperature defference of up to 2degC, Take it up to 10 or even 20degC and you can bring that down heaps - cant remember but from experience without doing calorimetric tests it seemed about 4% at a guess.


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## Baulko Brewer (19/5/11)

Thanks for the feedback,

My Brew currently sits in my garage where in Winter it can get to 10 degrees. Would a peltier warm up a 30 litre space sufficiently to do an Ale? and conversely, would it be sufficient to take the edge off the heat in summer to do say a lager??

Over the last few days, I ripped up an old computer and have started to build a prototype using the heatsink and fan from the CPU and bought a 10 amp peltier from Jaycar. I will run it off a battery I use for my electic outboard, to power it to save wiring it all up at this stage.I will check the temps with thermometer to see if I can generate enough heat/cooling for such a confined space. 

Those 12V portable warmer/coolers are the same principle except only 8-12 litres

I will post some pictures when I do it


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## QldKev (19/5/11)

I doubt this will work. I have one of those little fridges that you throw cans in for the car. It is ok at keeping the drinks cold, and over several hours will make them a bit cooler, but it can't even get warm cans cold (maybe if you left it overnight or two)

The other issue is the current draw. 10amps is a fair bit of power. Check the capacity of your deep cycle battery. If it is 120ah, you shouldn't really take it past 50% capcaity, so you have 60ah available. With your 10amp draw thats only 6 hours use! Even if you ran it from a power supply it would be an inefficient way of cooling it. 

QldKev


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