Wort Chiller

[2much2spend]

hi guys
just did my first AG today and it was good, it is going to be a good ale from early tastes.
i made up a wort chiller but im not happy with the way it cools, seems to be about 30-40
min for 23 ltrs and i used alot of water, i tried to restrict the flow and run it at capacity
didnt make a difference. thinking of doubling the run of copper or looking at a good gravity
feed plate chiller.
is there a better way? i have a 3 tier rig dont want to use pump.

 

[Bizier]

If you don't want to use a pump to create a counterflow whirlpool, you could add a motorised stirring paddle to a lid for the kettle and have your vertical chiller pipes mounted through it. This should bring you some efficiency without a pump, and also keep the outside air off your cooling wort.

 

[felon]

Did you stir?

 

[Andyd]

As the guys are hinting at, anything you can do to agitate the wort even a little bit will improve the efficiency of your shiller.

What is happening is thermal lamination - layers of wort end up at different temperatures, but because they're not moving the rate of thermal transfer is quite low.

That's the secret behind the whirlpool chiller - laminar thermal gradients are disturbed meaning that higher temperature wort comes into contact with lower temp coolant - the bigger the difference between them, the higher the rate of thermal transfer.

So to improve your efficiency there are three things you can do fundamentally:

1) disrupt the thermal layers in the wort (stirring, whirlpooling etc)

2) Disrupt the thermal layers in the coolant (convoluted copper tube makes a more efficient chiller because the water is not able to create stable thermal layers)

3) Drop the temperature of your coolant to create higher thermal gradients.

These are listed in order of diminishing returns.

Hope that helps!

Andy

 

[MaestroMatt]

I made a similar style immersion chiller had a similar problem.

The way I combat this is by getting some scrap copper piping that I cut of the original roll and creating a 'pre-chiller'. I run the water to the pre-chiller which is sitting in a bucket of ice water, from there it goes to the immersion chiller in the wort. This combined with giving it a good whirlpool every 2 or 3 mins means I can go from boiling to pitch temp in about 15mins. Just keep your whirlpooling relatively gentle and you won't have any problems with early aeration.

Quick enough for me and didn't really add a whole lot of cost to the DIY job.

 

[seravitae]

Also besides the thermal lamination effects, the rate of cooling slows down as the temperature of the wort gets closer to the temperature of the cooling water. You may find you get drastically reduced chill time by freezing a bucket of water the night before and recirculating that through your chiller. The ice will stay at a constant 0C (ish) providing a good temperature difference until it melts, and ice takes far, far more energy to melt per gram than water does to cool (while staying in liquid phase)

 

[Andyd]

Quite right about the impact of the thermal gradient and energy requirements Sera, although I don't like the idea of trying to recirculate the ice through a chiller - it will stay at (or close to) 0, but will also probably stay pretty much where it started unless you've got a chiller that will transport ice cubes

On the other hand, an external chiller in frozen ice might present a good addition, either as a primary chiller or as a pre-chiller for the cooling water. That's one addition I've considered, but not found necessary as our tank water stays pretty cold.

Andy

 

[2much2spend]

i had that idea too maestromatt i got some techni ice packs and raped them around the hose, didnt seem to do much.
i think i will make a very long and constricted coil and dump the whole thing in an ice bath. i shall post pics when it happens.

 

[MaestroMatt]

i had that idea too maestromatt i got some techni ice packs and raped them around the hose, didnt seem to do much.
i think i will make a very long and constricted coil and dump the whole thing in an ice bath. i shall post pics when it happens.

The thing about immersing the whole 'pre-chiller' in ice water means you have more surface area in the for heat from the water the be transferred out through the copper. By wrapping some ice packs around the inlet pipes you are really only giving it a small spot in which to pull heat out of the water.

Good luck with the build - As I said, I can recommend using this pre-chiller technique as a bit of an extra help for getting the temp down quicker.

I will try and get some pictures of mine tonight and post them as a visual reference to what I am talking about.

 

[mfeighan]

middle of summer last year i toyed with the idea of a pre chiller, whilst it helped bring the temps down to pitching temps i ended going through 3 bags of ice which seemed like a waste. Now i use a plate chiller which drops the temp a lot faster and the last few deg will drop in the fermentation fridge

 

[2much2spend]

i got it i think? a pond pump in a bucket of ice.
have the pump hooked up to the chiller (coil)
and return the water to the bucket with the ice
water, top up the ice as needed and should only
use about a bucket or two of water and ice. [post="0"]cheap pump[/post] :lol:

 

[RickyC]

I made a similar style immersion chiller had a similar problem.

The way I combat this is by getting some scrap copper piping that I cut of the original roll and creating a 'pre-chiller'. I run the water to the pre-chiller which is sitting in a bucket of ice water, from there it goes to the immersion chiller in the wort. This combined with giving it a good whirlpool every 2 or 3 mins means I can go from boiling to pitch temp in about 15mins. Just keep your whirlpooling relatively gentle and you won't have any problems with early aeration.

Quick enough for me and didn't really add a whole lot of cost to the DIY job.

I've got the same pre-chiller setup as MaestroMatt. Get down to ale pitch temps in 10 - 15 mins.

I also have a valve on the outflow of my wort immersed chiller, idea was to create some back pressure in the system and don't have to run down to the water tap to increase or decrease the flow.

I freeze up a big block of ice two days before brew day, it takes this long to freeze the massive block. On brew day I smash up the block and add water to a bucket to create an ice slurry and add the immersion pre-chiller.

Gently stirring or whirlpooling, carefully to avoid hot side aeration, is key to getting the temps down quickly too.

I was pleasently surprised at how little water I use with this setup and I now run the outflow through my sprinklers.

Don't forget the cold water should go in the top of the coil and the hot water out of the bottom.

 

[cdbrown]

As others have said, stirring makes a huge difference - also helps to cause all the break to settle in the middle of the vessel.

That's a nice looking chiller - Any chance of pulling the coils closer together and adding some more? The more coils the more heat transfer, it will also create resistance for your tap water reducing the flow and usage. But stir stir stir.