Peltier liquid cooling

Hello everyone!
I've started home brewing a couple weeks ago and came up with a small project to cold down liquids in general (BEER!)

I decided to use Peltier for several reasons, I do know there are other systems.

So, here's the idea... I'll have a copper container of 30x30x10 cm, holding about 900 ml of water. Inside of the container it will have a copper tube as some sort of serpentine to make liquid get trhough. So the water inside the container has the purpose to get cold enough so the liquid inside the serpentine can get cold as well. Is it clear as I explained?
My initial idea is that in the back of the copper container I'll place a few Peltier pieces spreaded along, making the surface cold, so the water inside gets cold too and consequently the liquid inside the serpentine.

As of the pieces.. I've searched and came up with this:

9x Peltier 12V 60W 5.8A TEC1-12706
Temperature Controler STC-1000
Power Supply 12V 50A 600W Switch Power Supply Adapter

I really need help on this part, I'm far from decent in electronics.. So, you guys think thats all the electronics I'll need? Suggestions to improve the stuff?

Thanks a lot for the help!

You might be onto something! But I don't know if those peltier units are liquid proof or very efficient?

Good idea though,

Well, I don't think the liquid proof is going to be a issue. It's well known that they can take at least a decent amount o humidity, since if very cold it condenses and freeze water. For the efficiency, I'am aware they are not the best option ever, but I'll stick to it for being very portable and relatively easy to acquire and assemble.

I might make it only six Peltier units and change'em to a more powerfull ones. I'm making the sketches to ilustrate better the whole thing.
Thanks!

OK, the prototype drawing is almost done!
So, now I'm worried if that power supply can hold that much wiring.. it's a total of 6 fan coolers, 1 water pump of 12v, 1 STC-1000 and 6 peltier units (TEC1-12706 of 91.2W each)

What do you guys think? Thanks!

Peltiers are one of the least efficient methods of cooling, per unit of energy input. That being said, if electricity is freely available, then it should work. You should understand that putting nine 60w-max-rated modules together does NOT get you 540 watts of cooling power.

Some advice from someone who heavily experimented with peltier cooled CPUs:

-running pelts at their maximum ratings is not efficient. normally you can double the energy efficiency by running at 50-60% of the max rated input voltage, and simply using more modules in series to get the desired cooling power.


-peltiers only cool as well as they dissipate heat; meaning the better the heat sinking you build into the hot side, the more cooling power or efficiency you can get on the cold side.

-Peltiers are typically less than 20-50% efficient; putting 100 watts of electricity in, usually gets you about 20-50 watts of heat pumped from the cold side to the hot side. this varies greatly, but efficiency is almost never higher than 50-60% under the best conditions

-cooling efficiency goes down in hot weather, sometimes very substantially. at 560 watts power (ie. 2-350 watts cooling), loosing 150w (50%) of the cooling capacity is not impossible in very hot weather or if the unit is in direct sun.

also, it is not a good idea to buy a 600 watt rated power supply (especially a cheap one) and put a constant, nearly-full load on it... look for a 800-1000w power supply and run it at 60-70% load for better power efficiency and longer device lifetime.


...now you may see why peltiers are not more widely used. they require a lot of engineering to make up for their lack of efficiency, and they start to eat a lot of power very quickly if you want to do more than cool a 1cu ft icebox with a sandwich in it.

a sandwich has the thermal mass of maybe 1 cup of water... and you want to cool gallons of beer. As an example, using an estimate of 300watts actual cooling for your setup, it would take 15 minutes to cool a 12-pack from 70*F to 40*F...

[12 x 12oz = 144oz or, 9lb of liquid in a 12-pack]
[300watts cooling = about 1025BTU/hour]
[70* - 40* = 30* temp delta to chill]
[9lb x 30* delta = 270 BTUs that need to be removed to chill that 12-pack from room temp to 40*F]

at 1025BTUs per hour, it would take [1/(1025/270) = 0.26] hours to chill that 12-pack (which is just over 1 gallon of beer).

So, your device should be able to chill a 12-pack-worth of beer from room temp to drinkable in 15 minutes (...assuming the cooling power, 300watts, was directly and instantly transferred from the peltier to the liquid, and that your insulation was 100% efficient and no other losses occurred).

Point taken. What would you suggest then for a home-made beer on tap? Thanks for the toughts!

I was looking for something to cool beer from a keg last week, so I made a few call to see what was available. I ended up cooling the keg by putting it outside cause it was a few deg over 0c where I was this weekends.

At first I was about to rent a setup called a "picnic" (thats how its called in french, IDK if there's a different name in english). Its very simple, there is a plastic cooler with a spiral of copper tube inside. You have to put ice/cold water in the cooler and I guess you have to add some at every X hour. You plug beer at one end of copper tubing, and cold beer come from the other end. Its really simple and you can that where there is no electricity.

I'm thinking about building one, i'll post pics and let you know if I ever do. But i'm also looking for a more permanent setup for my house, so if you ever succeed with the peltier cooler or any other electric/instant cooling setup, please let me know i'll be glad to hear about it.

Take a look at this link: https://tetech.com/product-category/liquid-coolers/

I just found that, i still need to figure out if this can be use to cool liquid from room temp to drink temp instantly. I guess if you go high enough in power/watts it can be done. At least you can take inspiration from their engineering if you still want to make it using peltier cooler.

One main thing i notice by looking at their design is that the copper tubing is directly connected to the heat sink by passing inside solid metal. That will surely conduct heat better (ie. taking heat away from copper tube) then having to cool standing water to then cool liquid passing through it in copper tubes. Its all about circulation and heat transfer capacity.

lionvert said:

I was looking for something to cool beer from a keg last week, so I made a few call to see what was available. I ended up cooling the keg by putting it outside cause it was a few deg over 0c where I was this weekends.

At first I was about to rent a setup called a "picnic" (thats how its called in french, IDK if there's a different name in english). Its very simple, there is a plastic cooler with a spiral of copper tube inside. You have to put ice/cold water in the cooler and I guess you have to add some at every X hour. You plug beer at one end of copper tubing, and cold beer come from the other end. Its really simple and you can that where there is no electricity.

I'm thinking about building one, i'll post pics and let you know if I ever do. But i'm also looking for a more permanent setup for my house, so if you ever succeed with the peltier cooler or any other electric/instant cooling setup, please let me know i'll be glad to hear about it.

Click to expand...

The english word for that is "jockey box".

So a while back I made a peltier cooled fermentation chamber. In order to do so it took quite a bit of research on my end, and couple mistakes which led to rebuilds, but a lot of knowledge gained by the end of the project.

So with that I will say you have a pretty good looking design going for you. I am glad to see you are planning on water cooling the hot side of those little peltiers. That is really the only way that you will have something viable with this project. May I recommend not looping all the waterblocks in series though. As the water passes through each block it will progressively warm up and ruin your dT of the last of the blocks in line.

You may want to look into upsizing your power supply. As was said above you should size the power supply to your total load, or have the load be about 80% of the powersupplies capability.

You really need to be concerned with you waste heat management. This system will produce crap tons of waste heat. So I think you have the right idea, but you really need to be aware of how much heat 9 X 60 watt peltiers will produce.

Also be aware of the dT of the actual peltiers. That rating is not based off ambient temperature or the temperature of the water, but is based off the hot side of the actual pelt chips. So getting the cold side down to -10 or so degrees c to get your output where you want it is possible but very difficult.

Here is quite possibly the best link I found after much searching for my project about a year ago. It was the most useful for me, and so I hope for you as well.

TEC/Peltier definitions, formulas, temp estimations

May I also say that you may want to look into hooking two or three of those nine peltiers in series from your power supply and running them continuously, only switching the remaining 6 or 7 at full voltage when the temperature difference in your copper reservoir gets warm.

[edit]
So I thought about it a little more. A few more things of note from what I learned.Do not, absolutely 100% do not use thermal interface epoxy to get your pelt sandwich built. It will literally ruin your day if you do. Use a good TIM for the love of god, and don't over torque the bolts pinning everything together. Once again, ruined day. So with that said, another amazing link I found which I think should prove very useful to you.

http://www.customthermoelectric.com/Guides.html

This link explains things so well on mounting, and thermal interfaces. On the page I linked not all the links are working, but most are under the guides pulldown tab.

Good luck man

I think you could do the same thing for a ton less money and effort by getting one of those really small dorm fridges. Hell, you might even be able to make a full blown kegerator for less money.

I respect your motivation, and the pelt devices are pretty cool, but IMO, they're ill-suited for your application.

Could you use the such a setup as a mash heater/wort chiller?

Use the hot side to maintain your mash heat while using the cold side to pre-chill some liquid that will later be used to chill the wort.

It seems this would be an interesting and easy way to save some of the wasted heat.