Immersion Chiller - one x long loop or multiple short?

[Matt in Birdham]

Hi all I am back from the near death experience of a full house reno/extension, finally having brewed up yesterday for the first time in ages..
Whilst chilling it down I was reminded of the fact that my current IC isn't really the fastest (20 minustes plus on 23 litre batch) - it is only 25 feet of 12mm copper and I used to use a much longer (single coil) IC down in Aus that was much faster. So I fancy building a better one, and in the US I see people raving about the multi-coil chillers from a company called Jaded (e.g. the Hydra). This has 3 x coils that seem to be arranged one above the other, with some overlap. After mulling how it would be possible to make something similar, I came across these 4 port manifolds from Speedfit which would make the split to multiple coils easy(ish). My question is, does anyone know about the physics of this? If I bought 2 x 10m coils of 10mm copper, would I be better off with 2 x 10m runs or 4 x 5m runs (could do a 2 coil version using a simple tee)? Any insights into how multiple coils should be best arranged, and direction of flows within each coil?
I quite like the idea of it as a project.

[IPA]

This is a better buy.

https://www.themaltmiller.co.uk/index.p ... ductId=343

It cools from boiling to 21 degrees in a single pass. You will a wort filter before the inlet and to rinse it immediately after use.

[Jocky]

Funnily enough I'm just in the process of building a dual coil chiller and so have mulled this myself.

The thinking behind the Jaded chillers is all about throughput of coolant. Multiple parallel coils are one way of avoiding coolant flow restriction, but they also stress that using the shortest hose possible to connect to the chiller, and turning your tap on full blast.

So the fastest cooling design is to have as many coils as you can to get the maximum flow rate.

[Matt in Birdham]

The thinking behind the Jaded chillers is all about throughput of coolant. Multiple parallel coils are one way of avoiding coolant flow restriction, but they also stress that using the shortest hose possible to connect to the chiller, and turning your tap on full blast.

So the fastest cooling design is to have as many coils as you can to get the maximum flow rate.

Yeah - I've been reading some stuff to that effect, but I am a little stuffed there as I have to chill about 10m from the nearest tap (still get a reasonable throughput though - I suppose I could also buy a larger bore hose). But flow aside, there must be some science to the layout/length of the coil? Or not? I wonder whether 2x thinner coils would cool faster than 1 x thicker, for example, if the throughput was the same? The Jaded chiller still has a 1/2 inch input I think, so does it really have a bigger throughput than a single, long coil? Don't know the answer to that either. Thinking about it some more, I suppose a decent length chiller (10m+) is going to restrict flow more than the hose connecting to it (usually) so making that as free-flowing as possible will help, as will having a relatively free-flowing exit (i.e. if running multiple coils, don't bother reducing back down to 12/15mm). I'm tempted to go for 4x 5m lengths with the JG manifold, but it is quite an expensive mistake if it doesn't work out. Could try 2 x 10m before cutting the coils I suppose..

IPA - I have considered a plate chiller before, but I really want to avoid the extra cleaning/sanitation issues that come with it, and also the extra pump required.

[Matt in Birdham]

A few quick measurements:

Garden Tap: 15.7 l/m
Tap + hose (1/2 inch, I think about 20m, unrolled): 11.5 l/m
Tap + hose + chiller + exit hose: 7.5 l/m

Observations:
1. My tap flow isn't great to start with, although I can't think of a good reason for that since we have a freshly installed 25mm blue water mains (and amazing pressure/flow at the stop-cock). Will take that one up with the plumber.

2. Hose loses a fair bit of flow, which is to be expected. An easy/cheap fix here is to increase from 1/2 to 3/4 inch garden hose which gives 4x the flow at a given length of hose.

3. My chiller (10mm, shop bought) is really constrictive, even though it is only 6.5m long, and since I have now confirmed it is 10mm OD I could just get one more length of 10mm and arrange something in parallel. Would that simply halve the resistance?

So if it *is* all about flow, the cheapest/easiest fix would be to try upping my garden hose size/shortening the length and also losing a few metres off my 5m exit hose (although I suspect most of the resistance is being provided by the chiller coil).

[jamesmb]

Funnily I'm on the same journey. There's a cool post over here https://forum.braumeisters.net/viewtopi ... bo+chiller and here
https://forum.braumeisters.net/viewtopic.php?f=4&t=2364
which inspired me to go 2x10mm mainly for durability and do-ability of construction.
I was tempted to use a "bullet manifold" to go 22mm to 4x8mm which would have the same cross sectional area as single 15mm but far more surface area (heat transfer and drag) I'm not sure what the hydrodynamics and the thermodynamics are but I'd hesitate to guess that you'd get a better flow for the surface area AND better surface area / volume ratio which I'm guessing are the key drivers with 4x8mm rather than 2x10 mm.
Then I'd keep the length of the runs to that which gives you decent flow (and hope)!
Me - I went for what I can more likely build. Bits are here.

[jamesmb]

PS - Looks like I haven't posted since I registred in 2013 so was purged. Have just re registered.

[Fil]

Fwiw it was a jaded product, the 'cyclone' iirc that was the inspiration for the 'flux capacitor'

a couple of lessons learnt are that 1) 28x hoseclips that need a wee check and tighten are a pita, and 2) the waste coax cable i used to spiral round the SS beer transport tubes to both guide a turbulant flow and keep the PVC sleeve centered will rust (woven steel mesh screen DOH!!)

Other than that tho CFC is way superior imho and the straight tube/cassette arrangement allows for simple tube brushing for those of us who need to see surfaces are clean.

[Matt in Birdham]

Thanks James, have you built your chiller now? If so, how is the performance? Still toying with the idea of 4 x 5m loops as the 4 way manifolds look like an easy way to make the connection, and show give essentially unrestricted flow. That, coupled with a 3/4 hose to chiller and the same (short length) for drainage should improve my chilling times a lot, if not water usage (another concern, tbh, but a worry for another time).

Fil that looks cool but the cleaning implications are horrendous (to me). taking apart multiple pipes and brush cleaning every brew? The great joy of the IC is the simple cleaning and guaranteed sterilisation when boiling for last few minutes. I guess you would get some high temp sterilisation when chilling through your CFC whilst temps are still hot though, although perhaps not towards the ends of the tubes when wort will already be chilled somewhat?

[Fil]

cleaning is a doddle, and while more involved than an IC the 10 minutes it takes pull one end of silicone tube off each tube and drop a long tube brush down n out the bottom with it sat in a washing up bowl, rinse with the tap and then leave to air dry.
The advantage over the traditional coil cfc or fixed plate chillers being no blind moisture traps in the beer transport path providing confidence (well i need it otherwise i could worry the weeks away before 1st sample of a brew.. )
a pre chill re circulation of the boil for 15 mins is how its sanitised pasteurising the interior, the pump and suitable hop filtration are required but the straight tube design of the chiller means it wont foul with any debris and cold break that gets past the kettle filter or is formed in the chill

.. when brewing a 23l batch an IC was ok but when upping to 2-3+ x the brewlength i didnt fancy a 90-120 minute stir n chill, the above chills a full kettle in a single pass from off the boil to pitching in less than 15 minutes. , (My IC a coil within a coil was not the most efficient!! but depending on the time of year it could take 40 minutes+ to chill circa 25l down to sub 30c with a constant stir to keep the wort moving over the cooling coils) with the upgrade to a bigger 98l kettle i needed an alternative..

moi? defensive?? just a lil ..

after a few years however it only takes a wee bit of sunlight to promote algea growth in the pvc water jackets as they can trap residual moisture, If i ever need to rebuild, the jubilee clips are not the only aspect i would upgrade.. ..

[Matt in Birdham]

Yeah I like the principle Fil, I'm just allergic to cleaning as it is the biggest PITA in my current setup/brew space. I know have full electrics (45A circuit) so I can brew electric in the shed with no extension leads, but still no plumbing - which I think is too much of an ask at the moment (would *love* a potable tap, sink and decent drainage out there). Hence, cleaning involves the kitchen, transporting stuff through the house and annoying the powers that be, or hosing things down in the garden..
I don't do too badly with my current IC, perhaps 20-25 minutes, but it is still annoying. Things were quicker with my old, longer and thicker one and the use of pre-chilled water/pond pump (ground water > 30C at times down in Aus). I'm pretty sure I can upgrade the IC to get < 10 mins all in, which would suit me fine.

[Fil]

some of the intricate multi coil ic chillers are Very effective im pretty sure ive read about one with something like 6 or 8 coils and a super complex balanced feed manifold that out strips cfc performance.. So you should be able to achieve the 10 minute saving ok..

iirc the super efficient IC mentioned above was a string of small coils suspended from the pot rim circling over a 1/3rd of the circumference, with super complex manifolds on the exit and feed.. i suspect something similar and simpler could easily be made, if you use silicone tube or pvc tube to feed/drain the coils and have them all run independently to waste(into cleaning trug), you need only worry about the input manifold, and with individual waste tubes if flow balance becomes necessary you can apply a simple clip to squeeze and restrict exit flows of individual coils to balance the flows.. being modular if you need more performance you should be able to add to it with minimal expense or trouble.

[Fil]

Also dont forget depending on the brew pitching @ 25-30c while actively chilling down to an optimum temp for primary can give the initial oxygen hungry population growth stage a good boost..

[Matt in Birdham]

Also dont forget depending on the brew pitching @ 25-30c while actively chilling down to an optimum temp for primary can give the initial oxygen hungry population growth stage a good boost..

Yeah, I've already got into this habit. Stop at about 24-25 now and pitch, dropping to ferment temps over the first 8 hours or so. Definitely haven't noticed a drop in quality as a result, and those last 5-10 degrees take forever when the groundwater is mid-teens. Looking forward now to some quick chilling over the winter with low single-digit ground water temps..

[MTW]

If you want fast chilling, especially in the summer, consider building a second small single coil which can sit in a pot of iced water ahead of the main coil. It speeds up the later stages a lot, for the cost of a £1 bag of ice per brew and an easy build.