A better Counter Flow Chiller

Hi folks finally decided to sign up on the forum. Great stuff here!

Figured I'd share a little project I've been working on - the Counter Flow Wort Chiller.

I built a CWC a month or so ago and its crazy efficient. Got my 212 degree wort down to 60 with the hose flow as low as physically possible. Now that's all well and good, but I didn't like the fact that I had to run hoses all over the deck and in the lawn not to mention the wasted water.

So I decided to improve on the design. My first thought was to do a closed-loop CWC using a cheap pump I got on ebay for about $15. A few hours and some parts from Lowes/HD and the pics below is what I came up with.

The pump works great! I get about 3/4 GPM flow which I think should be OK based on what I had coming from the hose on the deck and I only need a few gallons of water in total. Tomorrow I'll give the chiller a try with some boiling water to see if it can cool to within pitching temperature range without getting the coolant too hot over time.

I'll post back with my results. Hopefully this works and can help some people out. I've got some other ideas for a better chiller but one project at a time !

Lets say you have 5 gallons of cooling water at 0*C in your bucket (lets just say it's ice cold but doesn't have ice for now) and you are trying to chill 5 gallons of 100*C beer down to 20*C (pitching temps). It simply can't be done. At the very best, you'd get to 50*C.

Ok, lets say you have 5 gallons of ice water (50/50 ice/water by mass)... so ~9kg of water and 9kg of ice.
For the beer, you have 18kg at 100C going to 20C which means... 4.2 (kJ/kg*K)*18kg*(100-20) ~ 6000 kJ of energy to get it to 20C.
For the coolant, to melt the ice you need 333kJ/kg*9kg = ~3000kJ, which is enough to get half of your wort down to pitching temps.
That leaves you with 18kg of 0C water to cool 9 kg of 100C beer to 20C. Can it be done?
To raise 18kg of water from 0 to 20C, it takes 1500 kJ. That leaves you with ~1500 kJ (one quarter) of the energy loss needed left still.

So, I'd say it would work so long as you had maybee a 3:1 split of ice:water in your reservoir, or 13.5kg = 30 lbs of ice.

Yeah, someone tested it out a while back and it takes just over 40 pounds of ice in a closed system to chill 5 gallons. If you don't put the hot output water back into the ice, it should take less. You can replenish the missing water with hose water which would be a lot colder than the CFC output water.

Bobby_M said:

Yeah, someone tested it out a while back and it takes just over 40 pounds of ice in a closed system to chill 5 gallons. If you don't put the hot output water back into the ice, it should take less. You can replenish the missing water with hose water which would be a lot colder than the CFC output water.

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But then there's no reason to even mess with the ice bucket.

It works, I've done it using a sump pump, recirculating. I had every container I could find filled with water, frozen in the freezer.
My ground water in summer is too warm, so I gave this a shot.
Freeze a lot of ice, and it works better crushed. I also reused the water in the swamp cooler, so it did save a lot of water. It's a pain, but works.

I've used a post chiller (running the wort through it) with a CFC and I think it uses the least ice. I usually have just stirred the ice water which is a pain, but I think I'm going to set it up so a pump recirculates the ice water to keep it moving.

Punx Clever said:

But then there's no reason to even mess with the ice bucket.

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I'm not following you. I'm suggesting that you can feed the CFC with icewater which would be much colder than straight tap water. I'm assuming the tap temp is the issue. The water that comes out of a CFC or plate exchanger is pretty hot and it's counter productive to put it back into your icewater tank.

What I do, especially in the summer when the ground water is warm, is I use both an immersion chiller and a plate chiller. I used a 50' copper immersion chiller when I started brewing, but I noticed it took awhile. So I bought the Blichmann Therminator and it worked great, except in the summer, I couldn't quite get the wort temp down in the 60's. So....I hooked the plate chiller up to the immersion chiller in a 5 gallon bucket of ice to chill the water going into the plate chiller. Perfect! I can now chill 11 gallons of boiling liquid to 65 degrees in almost 10 minutes without using a tremendous amount of water. It's a bit expensive to have both, but time = money, and I'm all about saving time on brewday, especially when it comes to all-grain brewing.

PeckerWood said:

So....I hooked the plate chiller up to the immersion chiller in a 5 gallon bucket of ice to chill the water going into the plate chiller.

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whaaat. I think your logic is in a loop. The plate chiller cools the water going into the.... plate chiller? Miss-spelling? Or am I out of the loop?

Regardless, the key which many on this forum have found is that even lukewarm tap warm is useful as the initial coolant to take the boiling wort down quickly, then switching to a better coolant (ice water) for the final 10 or 20 degrees. Save the warm water for washing your gear, or pump it into the washing machine.

Sorry, it was poorly worded. I have my immersion chiller inside a bucket of ice that pretty much chills the ground water down that feeds into the water intake of the Terminator plate chiller. So as the boil kettle is draining, the fermenter is splash filling up with 65 degree aerated wort. I then use the hot water coming out of the plate chiller to clean my equipment while the kettle is draining. It takes about 10 minutes to chill 11 boiling gallons down to yeast pitch-able wort.

Bobby_M said:

I'm not following you. I'm suggesting that you can feed the CFC with icewater which would be much colder than straight tap water. I'm assuming the tap temp is the issue. The water that comes out of a CFC or plate exchanger is pretty hot and it's counter productive to put it back into your icewater tank.

Click to expand...

The OP was thinking along these lines:
"Now that's all well and good, but I didn't like the fact that I had to run hoses all over the deck and in the lawn not to mention the wasted water."

So I figure that running a hose to the ice bucket defeats the purpose of building the ice bucket for him in the first place.

Punx Clever said:

The OP was thinking along these lines:
"Now that's all well and good, but I didn't like the fact that I had to run hoses all over the deck and in the lawn not to mention the wasted water."

So I figure that running a hose to the ice bucket defeats the purpose of building the ice bucket for him in the first place.

Click to expand...

Not all goals are virtuous in the end I suppose. I was pointing out that what he was hoping to do COULD be achieved with 40 pounds of ice and then offered alternatives to consider. Those alternatives include modifying his original goals a bit and I think it falls in line with the basic premise of our forum here.

Feeding the icewater supply with new tap water doesn't really defeat the purpose of ice in most cases. Most people use ice when the tap temperature is too high to cool the wort to pitching levels.

If the most important goal to the OP is to chill remotely without access to a hose, then 40 pounds of ice and some water will do the job just fine.

Punx Clever said:

Lets say you have 5 gallons of cooling water at 0*C in your bucket (lets just say it's ice cold but doesn't have ice for now) and you are trying to chill 5 gallons of 100*C beer down to 20*C (pitching temps). It simply can't be done. At the very best, you'd get to 50*C.

Ok, lets say you have 5 gallons of ice water (50/50 ice/water by mass)... so ~9kg of water and 9kg of ice.
For the beer, you have 18kg at 100C going to 20C which means... 4.2 (kJ/kg*K)*18kg*(100-20) ~ 6000 kJ of energy to get it to 20C.
For the coolant, to melt the ice you need 333kJ/kg*9kg = ~3000kJ, which is enough to get half of your wort down to pitching temps.
That leaves you with 18kg of 0C water to cool 9 kg of 100C beer to 20C. Can it be done?
To raise 18kg of water from 0 to 20C, it takes 1500 kJ. That leaves you with ~1500 kJ (one quarter) of the energy loss needed left still.

So, I'd say it would work so long as you had maybee a 3:1 split of ice:water in your reservoir, or 13.5kg = 30 lbs of ice.

Click to expand...

Indeed it does not work that well. Its not that I didn't believe you or the math but I had to see this through to the end! The reservoir water quickly rose in temperature as did the wort output. Looks like back to the engineering drawing board for me - buying 30 lbs of ice just doesn't make sense when I can just use my hose and I already know it works at the lowest flow rate possible.

Too bad peltiers are not that efficient either because that was another thought I had.

Not all is lost. Just look at how cheap municipal water is.

mattwood2000 said:

Indeed it does not work that well. Its not that I didn't believe you or the math but I had to see this through to the end! The reservoir water quickly rose in temperature as did the wort output. Looks like back to the engineering drawing board for me - buying 30 lbs of ice just doesn't make sense when I can just use my hose and I already know it works at the lowest flow rate possible.

Too bad peltiers are not that efficient either because that was another thought I had.

Click to expand...

Yup, sorry if I came off wrong on that too... I just kinda "geeked out" for a second. It's been a while since I've done any engineering.

No worries man - I do that from time to time myself...occupational hazard