Flow Rate for Wort Chiller
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counter flow or immersion??
JJ
JJ
rod
beer -just brew it
i go as fast as it will take without blowing the lines off
Truble
Well-Known Member
I am now thermodynamics expert, but I use mine for every batch. I start out with a lot of flow, since it is moving a lot of heat at the beginning. After a minute or so, I slow the flow to about 50% of the available pressure, then half it again in a bit. No exact times, but more of a "feel" thing...also since I don't like wasting too much water.
Truble
Well-Known Member
The way I understand it, it is a matter of the water being exposed to the heat. When the wort is almost boiling, water need only be in the chiller for a second to become scalding. As the temp lowers, I think that it becomes less efficient. Not sure if this is a function of the temperature of the copper or what. I slow the water so that it is exposed to the coils for a longer time, so that I don't waste water. Also, I periodically, and VERY GENTLY, move the chiller, or stire the wort a little in order to break any thermal barriers that develop in the wort around the coils.
Truble
Well-Known Member
Glad to help.
MattD
Well-Known Member
It depends on what you mean by most effective. You'll achieve the highest cooling rate in an immersion chiller by using the highest flow rate possible. It won't necessarily be the most efficient in terms of water usage, but it will obtain the highest cooling rate. Remember, heat flow from the wort to the water is proportional to the difference in temperature, so every little bit you warm up the water in the coil, you're slowing the rate of heat transfer. The faster your flow rate, the less you let the water warm up, therefore maintaining the highest possible temperature gradient.
Now if you want to truly have a fast and efficient chiller, build yourself a counterflow chiller. An off the cuff idea for building one is this:
Get a plastic bucket of some sort, that has a tight fitting lid with a gasket. drill a hole at both ends of the bucket, either on the side or on the lid and bottom, whatever, doesn't really matter, but if you choose to put it on the lid and bottom, offset the holes to the side. put a fitting on each of these holes that can accept a hose. This is the shell side of your heat exchanger, where water will flow through. Next, measure the inner dimensions of your bucket. This will guide the design of your coil. I recommend a simple coil, so you can maintain counterflow (no direction changes). Thin wall tubing will have better heat exchange properties than thick, and thinner tubing overall will work better, although you'll need a longer length of it and it'll have a lower flow rate and be more prone to clogging (remember, you're gonna gravity feed the wort through it). Make the coils as large of a diameter as you can without actually having them against the wall, so that the wort has to travel as long a distance as possible inside the chiller. at either end of the coil form a straight section that justs axially out from the coil. Now drill a hole in the bottom and lid of your bucket in the center, and attach a watertight grommet of some sort the right size to fit your tubing through. Insert one of the straight ends of the coil through the bottom grommet, then lower the lid over the other straight end and snap the lid on the bucket. you now have a counterflow chiller for not a horrible amount of money! you can fit a siphon tube on both ends of the coil, and siphon the wort through the coil while at the same time running water in the opposite direction through the bucket. I might build one of these, now that I think of it. If anyone beats me to it, let me know how it works out!
Now if you want to truly have a fast and efficient chiller, build yourself a counterflow chiller. An off the cuff idea for building one is this:
Get a plastic bucket of some sort, that has a tight fitting lid with a gasket. drill a hole at both ends of the bucket, either on the side or on the lid and bottom, whatever, doesn't really matter, but if you choose to put it on the lid and bottom, offset the holes to the side. put a fitting on each of these holes that can accept a hose. This is the shell side of your heat exchanger, where water will flow through. Next, measure the inner dimensions of your bucket. This will guide the design of your coil. I recommend a simple coil, so you can maintain counterflow (no direction changes). Thin wall tubing will have better heat exchange properties than thick, and thinner tubing overall will work better, although you'll need a longer length of it and it'll have a lower flow rate and be more prone to clogging (remember, you're gonna gravity feed the wort through it). Make the coils as large of a diameter as you can without actually having them against the wall, so that the wort has to travel as long a distance as possible inside the chiller. at either end of the coil form a straight section that justs axially out from the coil. Now drill a hole in the bottom and lid of your bucket in the center, and attach a watertight grommet of some sort the right size to fit your tubing through. Insert one of the straight ends of the coil through the bottom grommet, then lower the lid over the other straight end and snap the lid on the bucket. you now have a counterflow chiller for not a horrible amount of money! you can fit a siphon tube on both ends of the coil, and siphon the wort through the coil while at the same time running water in the opposite direction through the bucket. I might build one of these, now that I think of it. If anyone beats me to it, let me know how it works out!
Truble
Well-Known Member
Understood, but that means that as the wort cools nearer the temp of the water that is running through the coils, the heat transfer slows, so in a sense it gets less efficient, and the only way to control is to speed up the flow of cold to keep the temp diff as big as possible, if I understand you correctly. Sounds right though.
MattD said:
Your idea for a CFC is a pretty good one. I remember in chemistry class in college we used a CFC to cool some kind of liquid in some experiment (the details have been hidden behind a homebrew fog). It was only about a foot long and the liquid wasn't in the CFC for very long at all and it still cooled it very quickly. It was made of pyrex though. I might give your CFC idea a try next time I'm feeling handy.
I use a pre-chiller and do not have an unlimited amount of ice. To be efficient, I run at a low speed and increase until the expelled water is at the temperature I would like the wort to be. Might not be efficient, but I only use 1 bag of ice and some salt to chill down to 80 F.
ETA: That's on a 3 gal boil.
ETA: That's on a 3 gal boil.
What kind of royalties are you due on those? Half a case? Just a sixer?
Beer Snob
Well-Known Member
Hmmm.... flow rate....never thought of it really. Turn on the water at full and let it sit till it's cool.....
MattD
Well-Known Member
Chairman Cheyco said:
Yours will work much better than mine. That's a pretty common method of doing a cfc in industrial heat exchangers, except the outer tube is metal is well. When you roll it into a coil, you have to have these struts inside to keep the outer tube from crimping the inner tube, which is why I thought it was a little too tough for a DIY project. Using a rubber hose for the outer hose is genius, it completely solves that problem. Kudos! I take it back, nobody build mine, everybody build the CC CFC instead!
the_bird said:
Half a case is way too much! A sixer will do...
Blender
Well-Known Member
I use an immersion chiller and once the wort gets down to about 120 I attach a pump and run ice cold water through the chiller and then back to the bucket that holds the ice water. Works real well although you have to purchase a pump. I stir the wort several times while it is cooling too.
Truble
Well-Known Member
Looking at that CFC has me planning one for when I start doing AG w/full boils. Nice job Chairman!
