Another cooling package engineer designing a chiller

So a friend of mine and I were looking at the wort chillers and thought 30 min was a long time to cool it off (we cool off 1000 lb-ft desil engines with 100 degree air in no time). So... we designed and built this. It cools 5 gallon boils down to ~60 in just under 7 minutes. Not sure if that is good for the beer or not but it sure causes a lot of junk to drop out of solution and so far the beers have been good that I've used it with.

What I started with:

Coils:

I wove solid copper wire and soldered the joints to make it stiffer... worked like a charm. After a couple boiling water baths to get it clean we were in business!

Looks good!

I take it that you have one water input, and dual outputs?

that is correct, the inlet splits right at the "water" line

I like it! How many feet of tubing did you use 50? Any more projects in the works?

Nice looking design.

ryanc525 said:

I like it! How many feet of tubing did you use 50? Any more projects in the works?

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yes it has 50' of 3/8"

I've been working on labels and the brewery logo, soon to become a lighted acrylic sign... assuming that works as planned I'll post pics of that build also.

I have been working on the mancave/ brewery quite a bit this summer... we just realized that we didnt take before pictures... maybe ill show a partial transformation on that one when its done.

there is always projects that need to get done... but thats what the homebrew is for!

jtsims21 said:

that is correct, the inlet splits right at the "water" line

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Was that done to increase the dwell time of your cooling water in the wort, or was it a by product of the parts you had on hand?

Nice neat work area, looks much cleaner than mine!

From what you are saying this is a HUGE jump in efficiency over the standard copper wort chiller! What I am not grasping however is from your second picture how you invert the smallest coil to fit within the medium coil?

Dwell time and pressure were increased with pinch clamps on the outlet hoses, they start open to help bleed out any air that is in the cooler, then i pinch them down to keep the outlet water warm until the end when they are almost closed. Not very high tech but it works.

the inner coil is cut off of the medium coil and shifted down then I soldered them back together with a union.

jtsims21 said:

Dwell time and pressure were increased with pinch clamps on the outlet hoses, they start open to help bleed out any air that is in the cooler, then i pinch them down to keep the outlet water warm until the end when they are almost closed. Not very high tech but it works.

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You don't just keep the water full blast the whole time? Is that just because you don't want to waste water? The reason I ask is because I use my outlet water to cool the outside of the kettle as well..set it in a tub that is slightly shorter than the kettle.

then i pinch them down to keep the outlet water warm until the end when they are almost closed.

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What's the point of this? Unless you are trying to save water (a reasonable goal) then it makes more sense to leave the water running full blast, doesn't it?

dutra2418 said:

You don't just keep the water full blast the whole time? Is that just because you don't want to waste water? The reason I ask is because I use my outlet water to cool the outside of the kettle as well..set it in a tub that is slightly shorter than the kettle.

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Basicly I am doing the same thing you are just all internal... the slower flow allows more heat transfer... the outlet water is just slightly cooler than the wort when it leaves so i dont loose thermal efficency, this also allows me to control the coils seperatly since they are run off of the same inlet.

It also saves water, in another water saving effort I also use the first bit of water that comes out to help clean my MLT... it is really hot so that helps clean the sugars that are left behind out... or at least thats what i tell myself.

the slower flow allows more heat transfer

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This makes no sense. More heat would be transferred with a higher temperature delta.

the outlet water is just slightly cooler than the wort when it leaves so i dont loose thermal efficency

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It depends how you define "thermal efficiency". Newton's law of cooling says that the maximum cooling will happen when you have the largest temperature delta. The way to have the largest temperature delta is to have as high of flow as you can.

Again, if you are trying to save water, that's fine, but don't claim that it cools better.

jtsims21 said:

Basicly I am doing the same thing you are just all internal... the slower flow allows more heat transfer... the outlet water is just slightly cooler than the wort when it leaves so i dont loose thermal efficency, this also allows me to control the coils seperatly since they are run off of the same inlet.

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Alright, as a degreed mechanical engineer, I am going to completely disagree with this statement. Convective cooling power is a function of temperature differential, mass flow rate, and the convective heat transfer coefficient. The mass flow rate is how much water is flowing through your heat exchanger, the temperature differential is the temperature difference between the cooling water and the wort, and the convective heat transfer coefficient is a function of the Reynolds number of the flowing water among other things. Decreasing the flow of water through the cooling coils decreases all of the variables in the equation which will therefore decrease the rate of heat transfer. Splitting a 50' coil into a pair of 25' coils increases the temperature differential allowing for more heat transfer. It also decreases the major head loss of the system and allows for more flow for the same input pressure. More flow equals colder water temperatures through the system and increases the cooling power albeit you use much more water.

You guys beat me to it. I'm a meteorologist, thermal dynamics (edit: thermodynamics..boned by autocorrect ) is kinda my thing . I would suggest using that outlet water to cool the kettle in a tub though....I'd be very interested if you could shave some more time off of that already impressive mark.

I recently built up a dual coil. It's a great way to cram a lot of copper under less water and at the same time, more efficient. It's like having two chillers in one. As far as flow rate, I just let 'er rip, start my clean up, and it's ready before I am. I'm on free well water so I don't worry about usage.

I'm an not a mechanical engineer so I can't tell you anything about the thermodynamics. But I am an industrial engineer so anything that increases brewer efficiency is a good thing. My last brew day was just 2 hours total including cleanup for a 5 gallon batch of extract brew with full boil on the stove top.


https://www.homebrewtalk.com/f51/my-dual-coil-immersion-chiller-260302/

Just the fact you are running 2 coils will save water since it will cool faster. Running the water slower will not save water because it will take longer to cool...

Monster Mash said:

Running the water slower will not save water because it will take longer to cool...

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Wrong. Slower flows transfer more heat into each unit of water. Therefore less water is needed. I turn down my water flow to save water. I'd turn it up ifi wanted to save time.

Ill give the "run it full bore" method a try to see if that decreases my cool time. I will be brewing Saturday, and I will let you know how it goes.

RDWHAHB said:

Wrong. Slower flows transfer more heat into each unit of water. Therefore less water is needed. I turn down my water flow to save water. I'd turn it up ifi wanted to save time.

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That was my understanding as well.

RDWHAHB said:

Wrong. Slower flows transfer more heat into each unit of water. Therefore less water is needed. I turn down my water flow to save water. I'd turn it up ifi wanted to save time.

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I too agree with this. The most efficient scenario would be when the outlet cooling water is the same temperature as the wort being cooled. In this case, the cooling water cannot absorb any more heat energy and slowing down any further will only delay the cooling process w/o actually saving any appreciable water.

If you are really concerned with saving water, you could use the discharged water to water the lawn/garden (once cooled), fill the washing machine, or any other re-purposing ideas that doesn't need fresh water (dishes, toilet, mopping, etc). Then again, you could always go no-chill (which I've had success with) and use no cooling water with a few hopping tweaks.

Update from yesterdays brewing... I tried the "run it full bore" method, there was a slight improvement, not really measurable since the outside temperature was also cooler yesterday. might have been 10-15 seconds quicker, but my outlet water was a lot cooler which in my case was a disadvantage because I use it to clean my mash tun.

Maybe it would be a larger difference with a larger mass to cool but with the volume that I am cooling I don't see the benefit of running without restriction.

Hey gang,

I just used my double coil wort chiller this morning on a 2.75 boil, went from boiling to under 90 in about 12 minutes. My tap water right now is mid 70's. I use a garden hose and by the time it gets out 100 feet, it's cool enough to water plants with. No waste and a lot easier than an ice bath.

We used 30 feet of 3/8" in a double coil design for a 3 gal pot.

Today is also my first at a full boil using 2 - 2.75 gal batches

Got to make good on what you have

Toy4Rick