Internal Fermentation Chiller

[pablo1337]

http://www.onlinemetals.com/merchant.cfm?pid=12917&step=4&showunits=inches&id=312&top_cat=1

I was looking at getting like 8 feet of this(or something similar) I ferment in buckets so therefore I can have a very large loop size. In addition I might get a tubing bender http://www.amazon.com/OEM-25179-Tubing-Bender/dp/B0014WIS5W/ref=pd_sim_sbs_hi_5

One thing that concerns me with your coil is how easy to clean and sanitize with how tight it looks to be wrapped.

I was thinking of using my 5 gal cooler HLT to hold ice water, put the pump in that.

My issue is that I was looking at building SOFC but I am moving in September and I cannot buy/make anything that takes up space. I only want to have ale fermentation temperatures, and 70 degrees F is fine for certain yeasts.

 

[kpr121]

Subscribed. This is WAYY cooler than my senior project!

 

[Navy_Chief]

Subscribed, way cool project.

 

[ceejengine]

Caveat: I am not an MechE, nor do I play one on TV. I did room with one once, but I told him to keep his thermo books far, far away from my delicate computer engineering eyes.

That said- wouldn't the tests you'd really be interested in be along the lines of "holding 50 deg. w/75-80 deg ambient"? The cooling tests would be a great proof of concept, but it seems to be, if you want it to be lagering device, then holding at a temperature is much more important (and now you need to worry not only about the heat being produced by the wort, but also the heat that seeps through the carboy insulation).

That said, I am fully prepared to be hilariously wrong. This does look awesome, and if it works would be a great way to lager (especially if you can keep the footprint small and ice exchanges to a minimum ).

And I agree- WAY cooler than my capstone projects!

 

[mdboulier]

You're not wrong at all. In fact thats exactly what we're dealing with. I've got plenty of answers for those points.

1) You could never reach a temp without being able to hold it. Theoretically, we'd be able to cool to 0C because thats the temp of the cooling fluid pumped through the heat exchanger. We can't because of heat entering the system from the environment through the insulation. This is why we're stuck at about 5C (41F). We can hold 41F as long as you might want (without fermentation heat).[notable - we've only used 1/2" foam for insulation on all of our tests]

2) We've measured the heat of fermentation - approximately. Its hard to get results that work across the board because different fermentations, specifically ale vs. lager, behave so differently. That being said, we measured about a 15 Watt heat generation during the peak of fermentation (at 70F ambient, ale at 1.051 OG = 5.12 kJ/[gravity point x gallon] excuse my mixing of english/metric). At that temp, our device can cool at a rate of about 300 Watts (plenty of power). Of course we don't have 300 Watts of cooling power near 40F because of the smaller temp difference in our coolant and the beer. That being said, the metabolism of a 40F fermentation is going to be significantly lower (compare 5 day fermentation period with ~10-14 days...maybe 5 Watts). The problem with testing this: its easier to measure heat flux in a controlled ambient environment (room temp) making it difficult to measure the heat flux at lagering temps (because we would have to cool the beer to maintain that temp its hard to tell whether heat enters from environment or is generated during fermentation). [Before anyone jumps on this, we made plenty of assumptions and are aware this test is NOT perfect. We just wanted to make sure we could numerically prove our cooling power was much greater than the heat produced from fermentation and are confident that we have done so.]

I will certainly post results on the lowest temp we can hold and the ice usage as soon as we have a long term fermentation testing running (soon). I do know this requires 11 lb of ice to cool 5 gallons from 80F to 40F (simple energy balance). The 5.12 kJ/Grav Pt/Gal from our heat of fermentation test (scale to this approximation any batch - 5.12 kJ x Gravity Points x Gallons, then divide by 334 kJ/kg of ice) would represent another ~1700 kJ of heat, or 11lb of ice. The initial 11 lbs will be exhausted within a few hours, while the 11lbs to counteract fermentation heat will be exhausted over an extended period (rate depends on temp and yeast, but overall heat should be relatively consistent). The rest of the ice will be consumed due to heat entering from the environment and will be minimal in a foam cooler.

 

[camiller]

Theoretically, you could circulate acetone chilled with dry ice. You would be able to make a 5 gallon beer-cicle. Not that I would want acetone near my beer, but you could probably find a food safe coolant that goes below 0C if you wanted.

 

[drummerguysteve]

You could also probably use ice and salt in an outer container, with your pump recirculating acetone in a container within the ice/salt bath.

It would be cheaper than dry ice, but a little more hassle.

 

[drummerguysteve]

Actually, I wonder (if it's in the same room) if you could just run the return lines into your kegerator... I've got about 2' of wasted headspace above my kegs, but a little shelf holding the kegs up would give me plenty of room to coil the return lines inside the fridge, and run them back out into the carboy...

 

[pablo1337]

You could also probably use ice and salt in an outer container, with your pump recirculating acetone in a container within the ice/salt bath.

You describe a closed dual loop system where the coolant is isolated. My understanding is that the pump that the O.P. used is submersible, and must be submerged in the coolant.

Actually, I wonder (if it's in the same room) if you could just run the return lines into your kegerator... I've got about 2' of wasted headspace above my kegs, but a little shelf holding the kegs up would give me plenty of room to coil the return lines inside the fridge, and run them back out into the carboy...

The only issue with this is that there is a question of how much the kegorator will chill the coolant when it passes through it. I am by no means an expert in thermodynamics, but you might need a reservoir of coolant, or a large amount of line in the kegorator to have any cooling power.

I am just waiting for my supplies and then I will be able to make my chiller:rockin:

 

[Ravenshead]

Instead of pumping ice water though the chiller, you could build a closed loop system.

Connect mdboulier's chiller to a cheap car heater coil ($20-$30) submersed in a water bucket.

Place said bucket in a dedicated beer fridge with appropriate feed-throughs.

Voilà, temp control.

 

[drummerguysteve]

I guess I did make a leap off topic when I went to a closed loop. I like the idea of a radiator in a bucket of water in the fridge. You could still replenish water as it evaporates, but wouldn't need to keep up on ice.

 

[mdboulier]

Instead of pumping ice water though the chiller, you could build a closed loop system.

Connect mdboulier's chiller to a cheap car heater coil ($20-$30) submersed in a water bucket.

Place said bucket in a dedicated beer fridge with appropriate feed-throughs.

Voilà, temp control.

I'm digging it. If you need extra cooling power, start that bucket with as much ice as you want. Basically move the ice water reservoir inside a fridge.

With regards to other coolants, if you're running them through a freezer, awesome idea. If you're running something like acetone through a fridge, you're going to lose power because acetone has a lower specific heat - use water if sub freezing temps aren't involved.

Also, we've been using two different pumps. The 12VDC pump can be submerged, but does not require it.

 

[mgara]

this is my cooling coil inside the refrigerator is a container with approximately 15 liters of water / alcohol, by a closed loop circulating pump. the bioreactor is isolated. pump is controlled by a mechanical thermostat. with temperatures of 30 º C ambient, 20 º C maintained.

 

[drummerguysteve]

I like it. I would need to make my coil much tighter so I could get it in a carboy, but a 10 degree C difference is great!

 

[magnj]

I'm thinking a bucket of salty ice water and starsan in my keggerator + pump + coil would make an amazing cooling system. Awesome idea!

 

[geniz]

I'm thinking a bucket of salty ice water and starsan in my keggerator + pump + coil would make an amazing cooling system. Awesome idea!

I'd forget about the starsan. You dont need it sterile and it would most likely fill your kegerator with foam.

 

[magnj]

I doubt it would foam with the in and out below the water but that's a good consideration. Has anyone run this yet through a regular ale fermentation? I'm really just trying to keep my ale temps down in the 60's in the summer, of course being able to do a lager outside of my keggerator would be nice too.

 

[drummerguysteve]

I'm going to put this together soon myself. I've got an unused freezer on the bottom half of my kegerator. It's too small for any vessel, and with the temperature controller attached to the entire unit, I can't use it to freeze foods.

What I'm trying to decide is the liquid to use. I don't think it will freeze very often, but water is out of the question since it will obviously freeze sometimes. I suppose acetone would work, but it is unnerving having it that close to my beer...

 

[magnj]

Anything other than water that would leak from this system into your beer would ruin it, and even in the case of water your not looking at a great situation either. So that being said, I don't see much of a difference between using something dangerous vs. water. Of course you don't want to use something that might give off toxic vapors or is explosive or something.

If you really want to get colder I'm thinking alcohol would help lower your freezing point, but I'm not sure it's necessary if you have a reasonable ambient temp. For the guys in Arizona fermenting in your garage, that's another story. But for me in NJ, I'm just looking to lower my fermentation by maybe 15-20F vs. ambient for ales.

I'd love to see someone implement this but either way I plan on giving it a shot, for the few bucks it's a worthwhile investment.

 

[drummerguysteve]

Why didn't I think of alcohol.... It's the obvious answer to any problem.

A half gallon of vodka in the water will probably keep it from freezing, and keep the water fairly clean/sanitized too.

 

[mgara]

30 % de alcohol en agua, a -15 ºC es liquido

 

[camiller]

Remember salt water is somewhat corrosive.

I threw out the acetone and dry ice thing as a joke because with dry ice you could get down to something like -70F which ultimately would give you a 5 gallon beer Popsicle.

 

[jfkriege]

Dry ice and acetone is fantastic for freezing the necks of champagne bottles when disgorging as a part of méthode champenoise.

 

[ceejengine]

Knew I was forgetting something in the achieving vs. maintaining question I second the suggestions that a simple tube exchanger might be the better part of valor- which would lead to some interesting spin-offs involving thermal siphoning, and passive (vs. active) pumping of the fluid... but definitely keep up the good work!

If you can design something that works, and is easy to clean and use, then that would be VERY useful. Ice consumption is probably a key factor here- if the design requires less frequent ice changes than say the SOFC systems, then that by itself is awesome.

 

[ceejengine]

And actually, thinking further about this... are there any thermowells out there that would be long enough & have the right diameter to serve as the 'sleeve' of the heat exchanger? I've seen some thin ones (https://morebeer.com/view_product/6666) designed for carboys, and of course stubby ones for use in HLT & mash tuns, but that would be the perfect starting point- there'd still be some welding to cap the other end, and insert the intake/out ports & internal tube, but a stainless one would certainly answer the metallurgical issues!

Would something that would push enough cooling 'power', though? This is where me being a thermo idiot comes into play... maybe I'll have to hunt my old roomate down and see if he remembers how to do that math

 

[mdboulier]

At the price of those thermowells, making your own might be easier. Stainless steel tubing is simple enough to find - capping is another ordeal.

I'm envisioning a 3/4" OD SS tube plugged at both ends with something like this. Drill 2, 1/4" holes in the top plug for the inlet and outlet lines.

SS takes away from the power and so does the pipe style (rather than the coil). There's pretty much no way to cool as fast, but hopefully the steady-state temp could be just as low (in reality I'd expect a few degrees higher because it will struggle to remove incoming heat from the environment at lower temps).

Regarding using AL, I boiled the hell out of our coils and saw some pretty nice AlO2 formation. I'm hoping this will work well long term. I've got a few pieces of aluminum soaking in some beers for now to see how it goes.

I'm throwing in a pic of the before/after boil effects as well as a few pics to help folks who want to bend a nice tight coil (1/2" pipe - 5/8" OD - is a MUST)

 

[Ravenshead]

Remember salt water is somewhat corrosive.

I threw out the acetone and dry ice thing as a joke because with dry ice you could get down to something like -70F which ultimately would give you a 5 gallon beer Popsicle.

LOL. I've taken dry ice and rubbing alcohol down to less than -40F for my kids' science projects--that's as low as my thermometer would go. Fun stuff.

 

[drummerguysteve]

That may work well for rapid wort cooling after a boil though, especially in hot climates, where I've heard even tap water gets hot! (ours is always cold, so this concept is so foreign, but I know it happens)

 

[Ravenshead]

I'd be afraid of solder joints popping. That's some major delta-T across materials with different coefficients of expansion. The differences are relatively small but the temp change is big.

I might try it some day just 'cause using water as a simulation.

 

[mdboulier]

Success! Brewed a lager yesterday. Chilled to 80F using traditional methods (limited by Atlanta's 65F tap water) then fired up the system with the aluminum heat exchanger in the carboy. Came back 2 hours later to see the carboy holding a perfect 12.0C (53.6F) with an operating range of +-0.3C.

We're currently using the aquarium controller (with 12VDC power supply - just bypass the internal 120/220 transformer) + 12VDC brushless water pump + 1/4" aluminum tubing coil HXer.

We started with quite a bit of ice, a whole cooler full really. It doesn't appear that much was consumed cooling the beer from 80F to 53.6F. Definitely less than 10lb. I will be keeping track of the amount of ice added for those that are curious.

Also, we did a small test with some aluminum to observe the effects on taste. Dropped some tubing into some beers and recapped them. We compared the control (recap beer with no aluminum) to beers that were loaded with pieces of Al tubing for 7 days....No metallic flavors!

 

[hatrickwah]

Subscribing. Moving to Houston, TX, trying to figure out how to cool my carboys. This looks awesome, but I too am worried about the aluminums effect on the beer. I would love to do this over trying build ferment boxes and therefore find space for the boxes.
Have you guys thought about building a glycol unit via an Air Conditioner unit and cooling your brew via the glycol?

 

[onthekeg]

Success!
Also, we did a small test with some aluminum to observe the effects on taste. Dropped some tubing into some beers and recapped them. We compared the control (recap beer with no aluminum) to beers that were loaded with pieces of Al tubing for 7 days....No metallic flavors!

If I remember correctly, this is a school project? Can you take it to one of the labs and have them run the AA or ICP instrument on the beer to see if the Al levels were higher?

 

[mdboulier]

If I remember correctly, this is a school project? Can you take it to one of the labs and have them run the AA or ICP instrument on the beer to see if the Al levels were higher?

Well its not quite as simple as walking a few brews over to the chem lab but, ya, that would have been an awesome idea. Too late to get fellow students to help now - its finals time. Thanks though. Maybe I'll leave a few samples behind and have some ChemEs run those tests this summer.

 

[magnj]

So has anyone built another one of these? I'm really thinking about it. How would it work in a corny? How many could I run in parallel off say a 5 gallon cooler w/ice?

 

[magnj]

Any update here?

 

[mdboulier]

I used it a few times. I think the aluminum was perfectly fine to use but don't hold me accountable. I figure I would notice the taste the levels were high. I haven't used this in a while. If you're going to construct your own to fit into a carboy, be patient and practice a few times.

I think plumbing through a fridge or freezer is the way to go. Adding ice to the recirc water daily was a PITA. If I didn't have to add ice all this time, this would be awesome.

Did you have a specific question?

 

[levifunk]

What about using a mini fridge's cooling unit instead of pumping through an ice bucket?