Chiller Advice - 1/4" Copper Or Not

[Bizier]

I have about 15m or so of 1/4" OD copper tubing that I made into an immersion chiller a few years ago, and never used because of flow restriction. I want to chill a 40L+ batch on a regular basis. The idea is to split this into smaller loops (e.g. 1x around the inside of kettle) and solder each end to an upright 3/4" or 1" manifold to increase the overall rate of flow through the chiller. I want to use this inconjunction with a march pump whirlpool.

Has anyone seen something similar, or done something similar? Comments from anyone engineering savvy? Would the flow be more even if the manifold outlet was at the bottom (with a U bend) rather than the top as in diagram?

 

[amiddler]

I'm far from an expert on how chillers work but I thought the idea was to keep the cooling water in there as long as possible to absorb as much heat as possible. With this set-up some of the water will be in and out quite quickly not absorbing much heat. It would work but possibly much slower than a normal coil configuration.

Drew

 

[Maheel]

i would make each coil say 2.5 loops to save on soldering and put the intake opposite to the outtake

that would give the coil support as you can solder the pipes to the "manifold" for support where they go past

might be a bitch to solder..... if you make the holes to close together.... working on one hole while causing a leak in another.. :wacko: .. air pressure (CO2?) test when done

i got NFI about how it would whirlpool but ?

 

[Bizier]

I like the idea of adding an extra 180 idea to make it stronger. I was figuring that I would temporarily wire it together so that it is hanging from a saw horse or similar while I solder. I have never used silver solder before, so I might be naiive, but at least I'll learn something. I'll pay attention to spacing.

Whirlpool is separately pumped from kettle outlet and returned back in on an angle so that it flows past chiller, and makes the rest of the wort move in a circular motion, though probably not smooth enough to form a nice cone etc.

 

[jasonharley]

I have about 15m or so of 1/4" OD copper tubing that I made into an immersion chiller a few years ago, and never used because of flow restriction. I want to chill a 40L+ batch on a regular basis. The idea is to split this into smaller loops (e.g. 1x around the inside of kettle) and solder each end to an upright 3/4" or 1" manifold to increase the overall rate of flow through the chiller. I want to use this inconjunction with a march pump whirlpool.

Has anyone seen something similar, or done something similar? Comments from anyone engineering savvy? Would the flow be more even if the manifold outlet was at the bottom (with a U bend) rather than the top as in diagram?

I think the key issue is get as much surface area of copper in contact with the hot wort. Also the thicker the copper tube the better the heat gradient so it can act as a heat sink. You also want to circulate water thru the pipes as quick as possible in order to create a heat gradient. I made a 1/4 inch 10 coil heat exchanger last week and tested it out. It dropped the temperature from 85 deg C to 27 deg C in 90 minutes .... still too long for my liking .... i am still experimenting. One of the big problems is summer and the temperature of the water in the water mains. I am in Brisbane and the main water temperature today was 24 deg C. To reduce the hot wort temp from 90 deg C to 26 deg C using 24 deg water, this would take 800 L of water assuming 100% efficiency .... if your system is inefficient then it will take longer and cost you more water.

 

[MHB]

You have there a most basic flaw in manifold design.
The way you have it drawn the shortest "Leg" is the top ring, so it will get the most flow, and the bottom leg is the longest circuit so will get the least flow with a gradation of flow diminishing from top to bottom.
You should have a U turn in one of the feeder pipes so all the legs are the same length.
First branch off the cold feed becomes last return to hot return.

Hope I'm making sense.
MHB

 

[Lillywhite]

I think the key issue is get as much surface area of copper in contact with the hot wort. Also the thicker the copper tube the better the heat gradient so it can act as a heat sink. You also want to circulate water thru the pipes as quick as possible in order to create a heat gradient. I made a 1/4 inch 10 coil heat exchanger last week and tested it out. It dropped the temperature from 85 deg C to 27 deg C in 90 minutes .... still too long for my liking .... i am still experimenting. One of the big problems is summer and the temperature of the water in the water mains. I am in Brisbane and the main water temperature today was 24 deg C. To reduce the hot wort temp from 90 deg C to 26 deg C using 24 deg water, this would take 800 L of water assuming 100% efficiency .... if your system is inefficient then it will take longer and cost you more water.

I had the same problem until my last brew, my original chiller was only about 5 or 7 meters of copper tube and I struggled to get the wort down to 35c in 90 minutes and that was with the garden hose coiled in an esky full of ice. Had enough so went to Bunnings and bought an 18 metre length of copper tube to build a new chiller, I then put the old short chiller in an esky full of ice with garden hose in one end and another short hose connected to the new chiller in the wort..........took only 25 minutes to cool the wort to 25c. The only problem I had was defrosting the copper tube in the esky to get started, put it in the esky about an hour or so before use and it froze the water in the tube, next time I plan on submersing in ice water instead of just straight ice.

 

[MHB]

More like this
M

 

[mh971]

I see where MHB is coming from but I think the floor is in the short distance of the water path rather than the flow. As water comes in it will only travel the length of one circumferance of the coil and beon its way back out, hence not absorbing enough heat.

An intact continuos coil where water has to travel the full 15m ( or 5 or 10 or what ever you have) allows the water to absorb as much heat from the wort as possible ( adjusted by the flow rate), these short circular sections manifolded I dont think will cool as well.

You want as much cold water as possible to be in contact with as much submersed copper surface area as possible with the flow rate adjusted so the water exiting the chiller is as warm as you can get it, this warmth is heat being drawn out of the wort.

 

[Ian Gommers]

Then, with these loops being 1/4 inch, as opposed to 1/2 inch, would absorb heat , relative to volume, quicker, requiring less time within the chiller? Therefore reaching maximum thermal exchange earlier than a standard 1/2 inch immersoin chiller?

 

[Ian Gommers]

It's how a radiator works people! :kooi:

 

[mh971]

Yes - longer flow path + maximum surface contact = more heat exchange = cooler wort faster.

 

[MHB]

I see where MHB is coming from but I think the floor is in the short distance of the water path rather than the flow. As water comes in it will only travel the length of one circumferance of the coil and beon its way back out, hence not absorbing enough heat.

An intact continuos coil where water has to travel the full 15m ( or 5 or 10 or what ever you have) allows the water to absorb as much heat from the wort as possible ( adjusted by the flow rate), these short circular sections manifolded I dont think will cool as well.

You want as much cold water as possible to be in contact with as much submersed copper surface area as possible with the flow rate adjusted so the water exiting the chiller is as warm as you can get it, this warmth is heat being drawn out of the wort.

And yet a multi plate chiller with a path length of one 150-200 mm works just fine.
Remember that the more pipes/plates for the same coolant flow rate the slower it travels more time to take up heat more effective cooling.
Heat exchanges must be the most misunderstood pieces of brewing equipment, take the post a couple up

I think the key issue is get as much surface area of copper in contact with the hot wort. Also the thicker the copper tube the better the heat gradient so it can act as a heat sink. You also want to circulate water thru the pipes as quick as possible in order to create a heat gradient. I made a 1/4 inch 10 coil heat exchanger last week and tested it out. It dropped the temperature from 85 deg C to 27 deg C in 90 minutes .... still too long for my liking .... i am still experimenting. One of the big problems is summer and the temperature of the water in the water mains. I am in Brisbane and the main water temperature today was 24 deg C. To reduce the hot wort temp from 90 deg C to 26 deg C using 24 deg water, this would take 800 L of water assuming 100% efficiency .... if your system is inefficient then it will take longer and cost you more water.

Nearly the only part that I don't disagree with is that the water temperature in Brisbane may have been 24^oC.
Surface area is definitely a factor, but far from paramount
No thinner is better than thicker, we are moving the heat through the pipe into the coolant not into a heat sink
Flat out isn't the most efficient answer, the coolant should be coming out at the temperature of the wort, any faster is just wasted water because it hasn't had time to cool the wort (get hot)
The last bit, well without stating the volume being cooled it makes no sense at all. I do know that high efficiency counter flow heat exchangers run at little more than 1:1 Product : Coolant, admittedly they tend to be multi stage and supplied with chilled coolant for the last stage.

Immersion chillers are going to be one of the slowest ways to cool wort and you will have to be patient. Water flow rates are always going to be an issue as the wort cools you can cut the flow right back. It's really all about the temperature differential and rate of transfer.
If you are in a hurry get a multi plate heat exchanger, better yet 2 of them and feed the second one with chilled coolant. I'm about to go back to a long counter flow tube in tube (6 meters of " SS in " copper) no blockages, no sterilisation issues and no copper downstream of the kettle.

MHB

 

[Ian Gommers]

Yay! I feel the warm glow of real knowledge. Thanx MHB! Thirstybunyip out...............till next time.

 

[Ian Gommers]

Thanks for that wonderful graphic Mick.

View attachment 43172

Yes - longer flow path + maximum surface contact = more heat exchange = cooler wort faster.

 

[Bizier]

Cheers MHB, and did you hack my PC and open the illustrator file that I thought I didn't save. Impressive graphic edit. That was basically what I meant by the 'U', added in the OP as an afterthought.

I figure that seeing as I already have a significant length of 1/4", and that it is cheap to get more, and that it makes sense that, provided you can work out a loop length where the liquid is not reaching terminal(ish) temperature too soon, then it should be more efficient to use it.

One thing that I think will make a big impact is to use a pump in conjunction with it, so that I maintain CONSTANT movement over the whole thing, and then tweak the flow rate so that you work out where abouts on the valve movement it is that it starts to really heat up.

I am considering getting more 1/4" copper and adding to the centre, or changing the design to something like the "ribcage" one that some bloke/s have that come up when searching the net. I have a 100L kettle, and I am thinking that I would like at least another set inside the main loop (pretty big area). I figure it won't matter so long as the lengths of tube are the same (centre ones are then coiled).

Can anyone give a rule of thumb for efficiency for the diameter of 2 sets of concentric loops in relation to the kettle diameter?
E.g if kettle diameter is 100, then make first coil diameter 70, and second 30?

Thanks for the input, I appreciate it.

ED: and as a lover of hoppy beers, I figure this is a bit of equipment that I want to f***ing rock. NC is great and all, but I want that genuine ultra-late kettle hop.

 

[Bizier]

And to throw another thing out there without really thinking it through:

How about a long grain bag/hopsock style (even SS mesh - then you could surround it in chiller coils) thing on the word return, where you are could partially trap trub, and even add a chute for hops to enter and use a lid so that it doesn't venturi air in (if that is even remotely possible). I like the idea of adding something like a hopback with immediate chilling, that you could keep adding hops to at whatever temp, and all with the lid on. Eg. you could stall chilling at some sub-isommerisation temp, add hops, recirc for a bit at said temp, and then continue with chilling regime. Might be able to pull other oils out of the hops. I really like those big melon notes you can get from hops. Perhaps I should just steep hops in vodka and add to a fermented NC batch... not such a bad idea.

It is late, I worked late, and <2 beers is not enough to make me too lazy to post such drivel. Maybe I just like pretending I am all good with diagrams. That's it, tomorrow I am buying plain-glass spectacles.

 

[felten]

or you could buy a blichmann hop rocket and a plate chiller

 

[MHB]

Cheers MHB, and did you hack my PC and open the illustrator file that I thought I didn't save. Impressive graphic edit. That was basically what I meant by the 'U', added in the OP as an afterthought.

I figure that seeing as I already have a significant length of 1/4", and that it is cheap to get more, and that it makes sense that, provided you can work out a loop length where the liquid is not reaching terminal(ish) temperature too soon, then it should be more efficient to use it.

One thing that I think will make a big impact is to use a pump in conjunction with it, so that I maintain CONSTANT movement over the whole thing, and then tweak the flow rate so that you work out where abouts on the valve movement it is that it starts to really heat up.

I am considering getting more 1/4" copper and adding to the centre, or changing the design to something like the "ribcage" one that some bloke/s have that come up when searching the net. I have a 100L kettle, and I am thinking that I would like at least another set inside the main loop (pretty big area). I figure it won't matter so long as the lengths of tube are the same (centre ones are then coiled).

Can anyone give a rule of thumb for efficiency for the diameter of 2 sets of concentric loops in relation to the kettle diameter?
E.g if kettle diameter is 100, then make first coil diameter 70, and second 30?

Thanks for the input, I appreciate it.

ED: and as a lover of hoppy beers, I figure this is a bit of equipment that I want to f***ing rock. NC is great and all, but I want that genuine ultra-late kettle hop.

No did it the really easy way, copied your picture into MS Paint and did some very rough cut and paste, graphic programs are not my forte.

Just a thought on how many "ribs" to use; if you work out the surface area of the bore of the feed pipes and the branch pipes, say the feeder pipes were 25mm² and the " ribs were 4mm² you would think 6-7 ribs would carry all the water the feeder pipes could supply. Not quite true as there is going to be more flow resistance in the smaller pipes but at a guess more than double would be unnecessary.

MHB

 

[Maheel]

If you are in a hurry get a multi plate heat exchanger, better yet 2 of them and feed the second one with chilled coolant. I'm about to go back to a long counter flow tube in tube (6 meters of " SS in " copper) no blockages, no sterilisation issues and no copper downstream of the kettle.

MHB

out of interest whats the issue in copper downstream from kettle ?

is it cleaning or does it impart a flavor, is this an issue for HB'rs ?