Proposed Hybrid Chiller Design

Got an idea for a hybrid chiller, and I'm wondering if anybody can spot the flaws.

Basically my idea is to put the copper coils in a 4-5 gallon bucket. The bucket is then filled with ice and water, and the hot wort run through the inside of the copper coils like a counter flow wort chiller. There's a hole at the bottom of the bucket to allow copper coil to drain out using gravity.

Pros:
* Allows use of ice
* Saves on water bills
* Allows me to convert my immersion wort chiller simpler, basically just one bend, instead of going through all the trouble of straightening it out, inserting it into the hose.
* Requires much fewer fittings, maybe one for running the coil out the bottom of the bucket.

Cons:
* Water will be heated by the water (This could be fixed by dumping the water)
???

I'm not even sure that keeping the water is a bad thing, since it's going to be around 40-50 degrees, which is always going to be colder than the hot wort.

Drawing:

The only problem I can see is the amount of ice you'd need. To cool a boiling wort to 68 degrees would require about 40-45 pounds of ice. You would have to find a way to drain out the water as it got warm and keep adding ice as it melted.

This is essentially a counterflow chiller, without the counterflow.

I used something similar to this design but did have a water exchange - in at the bottom out at the top. It worked ok. I then took half of 25 of the 50 feet of copper and made a real CTF and it takes less than half of the time and less water to chill my beer. I have made both and the Bobby's CTF is just as easy if not easier. I didn't solder mine but it still works great.

I borrowed the idea from www.zymico.com "El-Cheapo Chiller" - I just checked and that site is down now sorry

Good luck.

What I plan to do when I have my chiller built is to use a small pump I already have. Place the pump in a 5-6 gallon bucket filled with water and LOTSA ice. Pump the water into the chiller; output of chiller goes back to the bucket. If more ice is needed, dump it into the bucket, but be careful not to overfill it. I bought this pump about a year ago from Northern Tool for less than $40.00.

glenn514

weirdboy said:

This is essentially a counterflow chiller, without the counterflow.

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Well... not exactly. There is no counter flow, which would make things interesting I suspect. IMHO, that's a rather large difference, which may or may not cause problems. The big question is how hot the water is going to get from the hot wort flowing in. If it gets too hot then it might make sense to go to a full counter flow chiller.

Yooper - You might be right. My plan is to just add all the ice in the ice bucket and then fill the rest with cold water from the tap. I think this will probably give me an initial average temp of 40-50 degrees starting out. It's been my experience with the icy baths that I've added kettles to in the past that they don't heat up that quickly due to the large thermal mass the water represents.

The good news is that this is pretty cheap to try, since I've already got everything I need, and if it doesn't work I can go to a counter flow chiller.

BillyBeer said:

I used something similar to this design but did have a water exchange - in at the bottom out at the top. It worked ok. I then took half of 25 of the 50 feet of copper and made a real CTF and it takes less than half of the time and less water to chill my beer. I have made both and the Bobby's CTF is just as easy if not easier. I didn't solder mine but it still works great.

I borrowed the idea from www.zymico.com "El-Cheapo Chiller" - I just checked and that site is down now sorry

Good luck.

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Okay, I think that answers that question, all the water flowing through really is critical to the success of the chiller.

If you have a chest freezer or other large freezer, you could put water in the bucket and freeze it around the coils. Encasing it in ice. Then as the hot wort runs through the coils, it would melt the ice. You could then just put the bucket back in the freezer to freeze the water again.

Of course, I don't know how efficient the ice block would be once the wort starts to flow and there is a water insulation layer between the coil and the ice.

I liked the idea at first, but the more I think about it, the less I'm sold on it.

The big problem I see is that the amount of thermal mass of 4-5 gallons of water isn't very large. Take up the area with the chiller, and you probably really have 3 gallons of cold water in there.

5 gallons isn't that much thermal mass. Say that you have 3 gallons of water at 32F, and 5 gallons of hot water at 212F. Just think about that logically. There's a 180 degree difference between the two, and the hotter has twice the volume. I'd be surprised if you got below 120F. You'll probably go through the same amount of water as an immersion chiller, if not more.

With an immersion chiller, you're typically running quite a bit more than 5 gallons through. Same with a counterflow. This is why they work; they just keep supplying cold water until the temp is right. Brute force.

Now if you were running more water into the bucket all the time, it would be similar to an immersion with pump, but worse since you can't control water temp as easy.

DilvishTheDamned said:

It's been my experience with the icy baths that I've added kettles to in the past that they don't heat up that quickly due to the large thermal mass the water represents.

The good news is that this is pretty cheap to try, since I've already got everything I need, and if it doesn't work I can go to a counter flow chiller.

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I think that you'll end up with counterflow, but I look forward to seeing the results!

Remember, the hot wort is a large thermal mass also! It's mostly water too!

what if you replaced the ice in the bucket with dry ice as it is solid at a lower temp

bertman said:

what if you replaced the ice in the bucket with dry ice as it is solid at a lower temp

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You ever put dry ice in water?

what i meant was no ice/water just the dry ice.

P-Lay said:

If you have a chest freezer or other large freezer, you could put water in the bucket and freeze it around the coils. Encasing it in ice. Then as the hot wort runs through the coils, it would melt the ice. You could then just put the bucket back in the freezer to freeze the water again.

Of course, I don't know how efficient the ice block would be once the wort starts to flow and there is a water insulation layer between the coil and the ice.

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Won't work well. Ice immediately next to the coil will melt, warm, and become a nice insulator between the ice and the coil. Movement is essential in the ice bucket. Manual stirring is good, submersible aquarium pump is best.

passedpawn said:

Won't work well. Ice immediately next to the coil will melt, warm, and become a nice insulator between the ice and the coil. Movement is essential in the ice bucket. Manual stirring is good, submersible aquarium pump is best.

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+1
found that out with my pre-chiller in the summer when ground water is 80F. Gotta keep the cold moving against the copper!

DilvishTheDamned said:

Got an idea for a hybrid chiller, and I'm wondering if anybody can spot the flaws.

Basically my idea is to put the copper coils in a 4-5 gallon bucket. The bucket is then filled with ice and water, and the hot wort run through the inside of the copper coils like a counter flow wort chiller. There's a hole at the bottom of the bucket to allow copper coil to drain out using gravity.

Pros:
* Allows use of ice
* Saves on water bills
* Allows me to convert my immersion wort chiller simpler, basically just one bend, instead of going through all the trouble of straightening it out, inserting it into the hose.
* Requires much fewer fittings, maybe one for running the coil out the bottom of the bucket.

Click to expand...

What you think you gain in "reduced water bills" is replaced by "increased ice bills" or "increased electric bills". If you buy the ice, you'll actually pay more. If you make the ice, it's probably a wash. Tap water is about $.005 per gallon and you should be able to chill with about 30-40 gallons max. IOW, 20 cents.

You'll have to agitate the icewater aggressively to keep warm water from accumulating around the coils. You'll also melt all the ice well before you're done running off the wort unless you can get about 30 pounds in the bucket.

You'll do much better by pumping icewater through your existing IC.

kaiser423 said:

5 gallons isn't that much thermal mass. Say that you have 3 gallons of water at 32F, and 5 gallons of hot water at 212F. Just think about that logically. There's a 180 degree difference between the two, and the hotter has twice the volume. I'd be surprised if you got below 120F. You'll probably go through the same amount of water as an immersion chiller, if not more.

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This isn't quite right, because of the ice involved. If you got perfect heat transfer, you'd need just about 33 pounds of ice, or about 4 gallons of frozen water to cool 5 gallons of boiling water to a pitching temp of 71.5 F.

It takes 334 Joules of energy to change 1 gram of ice at 32 F to 1 gram of water at 32F. By contrast, it takes just 2.3 joules of energy to raise that same gram of water 1 degree fahrenheit. It only takes 25% more energy to heat water from a liquid at the freezing point to a liquid at the boiling point than it does to simply change it from solid to liquid without raising the temperature.

So if the proposed chiller design is predicated on melting ice to cool the wort, rather than 32F water to cool the wort, it is much more likely to work.

Of course, setting the system up to melt the ice efficiently is the challenge - you would need the liquid to efficiently transfer the heat from the coils to the ice.

i built a mock up of almost the exact same thing earlier this year. The problem I came up with with pumping the hot wort into the copper tubing. I used tubing to pump from my boil pot into my fermentor and the hot wort melted the tubing which made a huge mess. I'd recommend using copper to go into the hot wort.

Also I doubt that this would be more efficient that a good immersion chiller.

The other concern I would have would be making sure it's clean and sanitized. After a few batches I'd be worried about having old wort dry in the tubes. I thought about storing the whole thing filled with sani solution.

Okay, sounds like the first design isn't going to work very well.

So we'll go with something that's much closer to a CFC. However I think that this approach avoids some of the issues with CFCs. I live in the midwest, and that means that our ground water starts to heat up a bit. I don't think it usually gets to 80s but I could see it getting around 50-60, making a CFC much less efficient.

So I'm thinking about adding in and out flows for the water. This will allow flushing out of hot water, and the addition of ice in the form of "free" ice cubes (I've got a chest freezer full of water), and also some aggitation of the water from the water coming in the system from the bottom, and exiting out the top.

Yep that is exactly what I had for 10 or so batches. I ended up freezing 2 liter bottles and floating those in the bucket - I got lazy.

Like I said it works - it is cheap and easy to build.

I found once I used it for awhile I had the confidence to give the CFC a shot.

Good luck & have fun.

That looks a bit better.

Another thought I had is to just get a cheap pond pump, and pump the ice water through the immersion chiller in the wort. That way, you'd still be using an immersion chiller, but not using a ton of water. You could just add more ice to the bucket as needed and recirculate the chiller water.

I'm concerned about your system because what if the wort exiting is too warm? You'd have to pour it back into the boilkettle, or somehow run it through the chiller again.

I found once I used it for awhile I had the confidence to give the CFC a shot.

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So I guess I'm not really doing something better in otherwords. I'm fine with doing CFC, heck I'm about half way there already.

YooperBrew said:

Another thought I had is to just get a cheap pond pump, and pump the ice water through the immersion chiller in the wort. That way, you'd still be using an immersion chiller, but not using a ton of water. You could just add more ice to the bucket as needed and recirculate the chiller water.

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Welll..... I'd rather not spend the money on the pump. The other problem is that I've got a pipe down the center of my keggle, and a false bottom, so at 5 gallons I'm not covering the entire IC. So I would guess this would be more efficient since more copper would be exposed between water and wort.

I'm concerned about your system because what if the wort exiting is too warm? You'd have to pour it back into the boilkettle, or somehow run it through the chiller again.

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How is that different from a CFC? I mean essentially at this point that's what is it. A CFC you can put ice into. Heck I could probably put a lid on it, and run it at high pressure.

DilvishTheDamned said:

How is that different from a CFC? I mean essentially at this point that's what is it. A CFC you can put ice into. Heck I could probably put a lid on it, and run it at high pressure.

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It's really not different from a CFC. I wasn't sure you had a pump that could recirculate it back.

Still, coming out of the BK through the CFC is a one-pass deal for me and most others. I was just wondering about when the ice melts and the water warms, and it slows down quite a bit in the cooling if you had a way to recirculate it back into the BK.

I think what you've got now is a combined pre-chiller/CFC. I guess it wouldn't be a pre-chiller, though. More like a post-chiller/CFC?

Good drawing.

YooperBrew said:

Still, coming out of the BK through the CFC is a one-pass deal for me and most others.

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Oh, that's probably the correct answer, I might be trying to solve a problem that's not really a problem.

I live in the midwest, so it get a bit hot here, like 90-100 max, so I'm probably fine if it's a single pass for most people.

I think I'll go back to the CFC, I've got it about half made anyway, just need to straighten out the tubing, insert it into the hose, and sweat the inner tube to the outer tube.

DilvishTheDamned said:

How is that different from a CFC? I mean essentially at this point that's what is it. A CFC you can put ice into. Heck I could probably put a lid on it, and run it at high pressure.

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the difference is that with a counter flow chiller, you run a thin layer of cool water past the copper quite quickly, enhancing the heat transfer through the turbulence in the water. With your design (and I’m not saying it won’t work, just pointing out the difference) the water molecules that contact the copper surface are not exchanged as quickly, resulting in lower heat transfer coefficients. To some degree, these lower coefficients will be balanced out by a higher temperature difference, which will help to drive more heat transfer, but your set up is tricky to model, so you may as well build it and find out.

The design you've shown is exactly what I use in the summer. CFC's or immersion chillers are more efficient and easier to control the end temp, but they don't work so well here in the summer when the "cold" water comes out of the tap at around 93F. Using two 10# bags of ice, and about 2 gal of "cold" tap water it can get 5.5 gal of boiling wort down to the high 60's as fast as it takes to transfer. I usually freeze some water bottles and only buy one bag of ice. Jiggling the coils a little helps the heat transfer quite a bit, and can give you a little bit of control over the final temp.

During the boil I clean out my home depot orange cooler mash tun. Throw in 3 or 4 of the 2 liter frozen bottles that I have for my fermentation chamber into the cooler fill with water and put the lid on. This gets the water ice cold. When I chill my wort I use a immersion chiller hook up the tap first until I get as low as it will go with the tap 90-100. I disconnect the hose and hook up the cooler to the chiller letting the water from the cooler run wide open. It easily gets the temp down to or below ferm temps.
I use a "smaller" wort chiller I don't know the exact length but if I had to guess 20 to 25 feet. probably 20. And this set-up works GREAT.

JuanMoore said:

The design you've shown is exactly what I use in the summer. CFC's or immersion chillers are more efficient and easier to control the end temp, but they don't work so well here in the summer when the "cold" water comes out of the tap at around 93F. Using two 10# bags of ice, and about 2 gal of "cold" tap water it can get 5.5 gal of boiling wort down to the high 60's as fast as it takes to transfer. I usually freeze some water bottles and only buy one bag of ice. Jiggling the coils a little helps the heat transfer quite a bit, and can give you a little bit of control over the final temp.

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Which design? The one with the water inserted once, or the design with the water flowing through it. I'm also not sure how a CFC can be MORE efficient if this design cools down the water when the CFC cannot.

someone seems to come up with this idea pretty often and I always am forced to wonder how well it would work if you drilled a hole in the bottom of the bucket and whirlpooled chilling water from a hose (or pump with ice water).

DilvishTheDamned said:

Which design? The one with the water inserted once, or the design with the water flowing through it. I'm also not sure how a CFC can be MORE efficient if this design cools down the water when the CFC cannot.

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The one with the wort flowing through a bucket of ice water. I meant more efficient from an energy and cost standpoint, not as it pertains to heat transfer.

sound like you are setting up a still to me.