3/8" vs 1/2" copper coil for chiller

[kharper6]

Just wondering if anyone here has experience in comparing these two diameters and their cooling efficiency.

The price difference at my local hardware store is crazy between the two. I'm doing 10 gallon batches in a 15 gallon pot so I need something more than my 20' starter chiller.

 

[samandbekah]

Just wondering if anyone here has experience in comparing these two diameters and their cooling efficiency.

The price difference at my local hardware store is crazy between the two. I'm doing 10 gallon batches in a 15 gallon pot so I need something more than my 20' starter chiller.

I just picked up a 50' x 1/2" SS chiller from midwest, its got great reviews and says it's designed specifically for 10+ gallon batches... I'll follow up with the results after I try it... Everything I've read between the size differences is that the 1/2 is better... We shall see...

 

[kh54s10]

I can't say to the speed in chilling difference for sure but it should be fairly significant. I use two 20' coils of 3/8". I have it set up so I can use both in the wort or put one in a bucket of ice water.

I chose the 3/8" because of the $$$.

If I ever make another one it will be 1/2 inch.

 

[billl]

The 1/2 has about 33% more surface area to conduct hear. How that translates into cooling impact depends on flow rates etc, but it will certainly be faster. If the price difference is more than that, you could always just make a longer 3/8" one.

 

[Brewmenn]

I have not built mine yet so i don't have actual experience. But based on what I know about cooling, all other things equal, multiple runs of smaller diameter should cool better than a single run of larger diameter. More surface area.

 

[max384]

I have not built mine yet so i don't have actual experience. But based on what I know about cooling, all other things equal, multiple runs of smaller diameter should cool better than a single run of larger diameter. More surface area.

The problem is that not all else will be equal. No matter how much surface area you have, the 1/2" will flow more water per unit time. Now, the question becomes at what point does the faster flow of water with less surface area balance out the greater surface area with a slower flow rate. This I don't know. What I do know, however, is that as the length is increased past a certain point, there are decreasing returns on investment, since after a certain point, the water temperature within the tubes will have reached equilibrium with the wort temperature (or very close to it). At this point, additional surface area won't help at all.

 

[Black Island Brewer]

I brewed for years with a 3/8 chiller, but when Home Depot had their crash clearance on copper tubing, I bought 50' and made a new chiller. I have been pleasantly surprised with the difference. I can get from boiling to 140 in less than 5 minutes (which allows me to put the lid on my BK) compared to just under 10 with the 50' 3/8 chiller. How fast for the rest is more dependent on the current ground water temp, but I have been very pleased.

 

[kharper6]

1 got 1/2" because of an open box sale at home depot. Walked out with 50' for about $45.

How the hell am I supposed to get a 90 degree bend in this thing lol

 

[Stealthcruiser]

How the hell am I supposed to get a 90 degree bend in this thing lol

Gradually.........

 

[kharper6]

Gradually.........

It's sitting on my porch now full of water. It will be frozen within the hour. Hoping this helps me make those close 90 degree joints. I have a jar I'm going to help bend it with. We'll see how it goes!


I wrapped it around a corny keg + 2 towels to give it a bit of extra diameter.

 

[beernbourbon]

How the hell am I supposed to get a 90 degree bend in this thing lol


there is a tool for that.....looks like a tightly wound spring.... has kept me from kinking copper tubing for years....buy a set of 3 sizes for like 15 bucks or something like that.

 

[Brewmenn]

The problem is that not all else will be equal. No matter how much surface area you have, the 1/2" will flow more water per unit time. Now, the question becomes at what point does the faster flow of water with less surface area balance out the greater surface area with a slower flow rate. This I don't know. What I do know, however, is that as the length is increased past a certain point, there are decreasing returns on investment, since after a certain point, the water temperature within the tubes will have reached equilibrium with the wort temperature (or very close to it). At this point, additional surface area won't help at all.

But you missed the part about single vs. multiple runs. Two 3/8 inch tube will flow slightly more than one 1/2 inch tube. But the two 3/8 inch tubes will have considerable more surface area for heat transfer that the one 1/2 inch tube.

The same works for length, the reason you stated. Two 25 foot runs will cool better than one 50 run.

The down side is that it's more work to build and maintain as you will have multiple connections to deal with.

 

[Epimetheus]

You always need a given volume (mass) of cooling water to lower the temperature of the given volume of wort. regardless if you use 3/8", 1/2", copper, stainless, or concrete tubing. You want the heat to transfer fast, so concrete is terrible, SS is OK and might be needed to meet sanitary code, and copper transfers heat the fastet.

With 1/2", the flow can be slower. With 3/8", the flow must be faster for the same time cooling the wort. Given a SINGLE tube of each. If you have doubled 3/8, you can have more flow (more heat removal) than a single 1/2"

The 3/8" tubing will have a larger surface area per volume of cooling water compared to 1/2" tubing. Therefore, the same volume of water flowing through a 3/8" tube will absorb heat faster than a 1/2" tube. Given the same length of 3/8 and 1/2, the temp exiting the 3/8 will be higher. You probably removed a teeny bit more heat from your wort.

But ... If the wort is 120d and the exiting water is 115d, those last few inches ain't pulling much heat. If the exiting water is only 80d, there is a biger temp diference, you are pulling much more heat all through the tubing.

 

[Epimetheus]

The other thing is, you must stir the wort. That really helps, regardless of tubing size. You have to replace the already - cooled fluid touching the coils with the hot stuff.

 

[HappiBrew]

You don't need a perfect right angle. Just curve it to whatever ergonomic shape fits you best. I didn't use anything but a paint can to coil and shape all my bends.
P.S. The green shading in the pic is from the camera, not the coil.

 

[kharper6]

Yeah this is a ****ing disaster. frozen soap water in it with the spring bender, 3 kinks at the bottom when I wasn't even close to 90 degrees.

Guess I get to drop cash on a soldering kit and hack saw now.