Gravity feeding immersion chiller?

[Jocky]

I was wondering - in a 3 tier setup would it be possible to gravity feed cold water from the HLT through the immersion coil?

I'm planning my 3-tier brewery out, and trying to take a low-faff/energy efficient route, and wondered if I could use the HLT as a pre-cooling reservoir by putting ice bottles into it, running water into it under mains pressure to cool further and then let gravity push the extra-cool water through the coil.

I'm just not sure if it'll have enough head pressure to work, or whether I'll need a little pump to help drive it.

[Dave S]

I was wondering - in a 3 tier setup would it be possible to gravity feed cold water from the HLT through the immersion coil?

I'm planning my 3-tier brewery out, and trying to take a low-faff/energy efficient route, and wondered if I could use the HLT as a pre-cooling reservoir by putting ice bottles into it, running water into it under mains pressure to cool further and then let gravity push the extra-cool water through the coil.

I'm just not sure if it'll have enough head pressure to work, or whether I'll need a little pump to help drive it.

I was casually thinking of trying something similar but with a coolbox full of iced water. The plan being to pump from and return to the coolbox. Don't think it would work though as I think the return water would heat the coolbox water far too quickly. Might have a little trial of the idea though at some point.

[Waffty]

Gravity would work perfectly, the only problem would be the height required to get enough pressure to go through your coil. And yes having attempted to use a flash cooler to cool my wort, I can confirm that they don't stay cool for and deffo not long enough to cool any great volume of wort.

[Jocky]

The plan being to pump from and return to the coolbox. Don't think it would work though as I think the return water would heat the coolbox water far too quickly.

Yes, the coolbox won't stay cold at all, unless you have a very, very large coolbox, as your boiler heat will be transferring from the boiler to the coolbox until they reach thermal equilibrium (the same temperature).

In very simple and rough terms (assuming a closed system with no heat loss or absorption), you want to take 20 litres of wort from 100C to 20C. If you were to mix in 20 litres of water just above freezing (we'll say 0C) you'll end up with 40 litres at 50C. Very roughly speaking the same will happen with your system, and to get your 20 litres of wort to 20C you'd need (I think) 80 litres of water at 0C.

[lord groan]

As others have said, you'd need a fair bit of height to get the pressure needed. My 'eco' solution to this, after being put on a water meter was to fit guttering to my tiny brew shed, collect the rainwater in a water butt then use a cheapo 12v ebay pump to push the collected water through the IC, then the hot IC output water back into the top of the rainwater butt. With a 23l brew needing cooled my 210l water butt had enough cool water to drop the brew to about 25c in roughly 45mins. This does work better in winter when the stored water is much colder, but then I don't brew from june-sept as I cannot cool my fermentation cupboard (yet) so the warmer ambient temp is irrelevant then
hth

[Jocky]

Yep, I think that the issue for me is that I'd need to put the HLT on the roof to get enough pressure to gravity chill when brewing on the patio.

I will have to use a pump.

[Kev888]

You could consider using room/air/ground temperature water initially whilst the temperature differential is high and the heat transfer very fast/efficient, and introducing your iced water idea later on when the wort is cool enough that the transfer has become slower - thats when I find most water is used and when cooler water would seem most beneficial.

Another option for conservation is to use clean/tap water initially and collect the runnings from that in a high container; you're then collecting both water and heat that would normally be wasted, and which can be very usefully redeployed for cleaning the boiler and mash tun.

And a bit left field, but the ultimate answer for conserving water is probably no-chill - common in Australia where these things clearly matter. There are concerns over DMS being trapped and the cold break being much less effective, but lots of people seem to get on with the method fine so possibly those concerns are over-stated; I can't say from any great experience but its something I'm intending to try more. It also has the advantages of not adding any cooling time to brew-day and allowing fermentation to be a separate event, when convenient days/weeks/months later - so wrt conservation 'if' it works I'm intending to brew larger, more water/energy/time efficient batches and split the wort from these into smaller cubes - to be fermented individually later as and when I want.

Cheers
kev

[brewnaboinne]

Agree with Kev, something I've done in the past is use the air temp gradient at first, then use immersion chiller, then put bottles of ice directly into the boiler.

[Jocky]

All good ideas there.

I have a medium rain water butt which I may hook the chiller up to with a pump, and will collect the water for cleaning or otherwise attach the garden sprinkler at the other end.

Equally I have become less worried about water saving when I realised water is metered at £1.47 per 1000 litres.

No chill is something I'm going to have look at soon.

[Dave S]

The plan being to pump from and return to the coolbox. Don't think it would work though as I think the return water would heat the coolbox water far too quickly.

Yes, the coolbox won't stay cold at all, unless you have a very, very large coolbox, as your boiler heat will be transferring from the boiler to the coolbox until they reach thermal equilibrium (the same temperature).

In very simple and rough terms (assuming a closed system with no heat loss or absorption), you want to take 20 litres of wort from 100C to 20C. If you were to mix in 20 litres of water just above freezing (we'll say 0C) you'll end up with 40 litres at 50C. Very roughly speaking the same will happen with your system, and to get your 20 litres of wort to 20C you'd need (I think) 80 litres of water at 0C.

No, I didn't really think it would work either for the reasons you state. And if you could get a coolbox big enough for it to work you'd probably be using as much water as running it straight from the tap.

[Dave S]

You could consider using room/air/ground temperature water initially whilst the temperature differential is high and the heat transfer very fast/efficient, and introducing your iced water idea later on when the wort is cool enough that the transfer has become slower - thats when I find most water is used and when cooler water would seem most beneficial.

Cheers
kev

That was my next thought, get the bulk of the temp down, as you say that happens quite quickly, then move to the closed system.