Cooling times with immersion chiller

[Ben2083]

I am currently using an immersion chiller which is made for ~12mm stainless steel pipe wound in to a coils, you know the type, to cool my wort after the boil. This came with my AG setup that I bought second hand as a job lot. Whilst it does the job, and I have made some pretty good beer, after having read various things around the interweb recently I feel it takes a lot longer to chill than I could achieve with a different setup. To get my 20litres of wort from the boil down to pitching temperature it can take 45mins or more. From what I read a half decent counter-flow chiller could do the same in under tens mins.


So, I am doing something wrong with my immersion cooling coil, or is a counter-flow chiller just that much better. Is there a way of improving performance with my existing kit? I am aware I have no flow of the wort with no recirc pump or similar, so that cannot help. I have a copper chiller available too but not currently hooked up, it’s probably a similar number of coils, so would I see much of a difference from the different material?

 

[IainM]

Swirl it around while you chill.

 

[foxbat]

Yes stir constantly. Its tedious but you'll do it in half the time.

 

[Bigjas]

I think a copper cooler would be better than a stainless one as copper dissipates heat better? I swirl mine around as its cooling and it takes about 30 mins in the summer and 20 mins in the winter when the tap water is cooler. I have looked at counter flow chillers and plate chillers, but the faffing around cleaning them puts me off.

 

[stan.distortion]

I think a copper cooler would be better than a stainless one as copper dissipates heat better? I swirl mine around as its cooling and it takes about 30 mins in the summer and 20 mins in the winter when the tap water is cooler. I have looked at counter flow chillers and plate chillers, but the faffing around cleaning them puts me off.

Fluid to fluid heat exchange is very efficient so copper should be a little better but probably only by a very small amount, maybe not even noticeable with ambient and water temp variations. A week or so ago someone mentioned using a second a pre-cooling coil inline, in a bucket of iced water initially iirc and then they modified a freezer to run the chilling water through before it got to the wort chiller. Seemed like a good idea, iirc they only ran it when the wort was down to something like 30deg as it made little difference to mains temperature water at higher wort temps.

 

[Ben2083]

Thanks for the replies everyone. I brewed yesterday and stirred pretty much constantly. My arm felt like it was going to fall off after, but it definitely improved the time to cool. Might have to look in to rigging up some kind of auto-stirrer, maybe with the electric whisk or a paint stirrer or something, will also help with wort aeration too. Either that or i'll hit the arm and work on the arms.

 

[Torshon]

Yes stir constantly. Its tedious but you'll do it in half the time.

Get a cordless drill stick in a plastic spoon and let it spin, obviously a purpose made stainless steel one is better but I use the one I got with a beginners kit, works perfectly well.

 

[AdeDunn]

I use my pump. Obviously you need to constrain the hops somehow though, else they just clog the pump up (even mine....), massively reduces the time it takes to cool all year round. I still use a huge quantity of water though sadly...

I actually deliberately built my system so I could use the pump whilst cooling, with a "whirlpool" port near the element (as a bonus, it's good for turning on whilst bring to the boil, helps me to keep the wort moving over the element without murdering my shoulder) with a piece of cured silicone hose attached (else the 90 degree elbow kept getting knocked down to point at the bottom...).



I've modified it again slightly since that was taken (this was actually taken after making tweaks right after a brew day, including adding the silicone hose to keep the whirlpool pointing in the right direction). Took the middle bazooka out (put a small pickup back in, as I never use that particular tap except when cleaning the boiler sometimes), and fitted a "spacer so that the bazooka on the left is further into the middle, all so I can fit my false bottom in with greater ease (before the legs kept hitting the bazooka filters, costing me a couple of inches at least). The wort swirls around the boiler just enough to accelerate cooling, but my pump is that bit too small to actually whirlpool the trub into a cone.

It's a simple solution, that saves me a LOT of labour. Oh, and if you are wondering why it's in the bottom, note I mentioned fitting a false bottom... If it was higher up it'd make it impossible, this is an all in one RIMS BIAB system I built, where mashing and boiling are all done in the one vessel.

I've also tried using a cordless drill and wine degasser to whirlpool whilst cooling, but cordless drills are pretty darn heavy to hold over the boiler for 15-20 minutes.....

 

[Dutto]

Heat Transfer is basically dependent on:

1. Thermal Conductivity of the material used (Copper is 223 and Stainless Steel is 7 - 23).
2. The thickness of the metal being used.
3. The surface area over which the transfer takes place.
4. The temperature difference between the two materials.
5. The speed at which the two materials pass each other on either side of the material being used.

So:

1. Using Copper instead of Stainless Steel will give better heat transfer.
2. As a general rule, copper tubing is thinner than stainless steel tubing because it is easier to extrude.
3. A longer coil will give a greater surface area, as will a greater diameter of tubing.
4. In summer time, tap water is warmer and it will take longer to cool the wort than in winter.
5. Stirring the wort will increase the speed of the wort and speed up the temperature is drop; as will using a smaller diameter pipe and a counter-flow system.

I use this immersion cooler made from 15mm copper tubing. It works fine.

The construction of a counter-flow tube cooler is beyond my abilities.