Ultra-budget fermentation cooling system

[RPh_Guy]

Here's my idea:

Get a small submersible pump, put it in a cooler filled with ice/cold packs, run a good length of tubing (100 feet?) from the pump coiled around my fermentor, and then back into the cooler. The pump will be controlled by my inkbird temperature controller.
Insulate the fermentor with a blanket or similar.

Pros:
-Super cheap. The pump and tubing cost less than $20 USD total. I have a temp controller and "free" foam cooler already.
-Controller able to highly regulate temperature by turning pump on and off.
-Gentle rate of cooling, won't overshoot.
-Able to cool the top of the fermentor, not just the bottom.
-Doesn't take up much space or much power (pump is 15W or so). Almost any pump will work.
-Set and forget (cooler should keep the ice water cold for at least a few days probably).
-No need for submersible temperature probe.
-Doesn't submerge fermentor spigot.
-Able to use on top of Fermwrap heater if needed.
-Simple. Somewhat easy to set up -- wrapping the tubing around the fermentor is the main effort. Cooler position doesn't matter.
-No open standing water (if the cooler is covered).
-Fits all shapes and sizes of fermentors.
-Quiet (depending on pump).

Cons:
-Requires ice (probably).

Does this seem like a reasonable?
Is there an option for some kind of jacket rather than just using the tubing without breaking the bank?
I'm open to ideas.

My other thought was using a swamp cooler with a fan plugged into my inkbird but that seems less reliable.

 

[helterscelter]

gotta-brew.com has very reasonable jackets for buckets/fermenters -- I've personally done both, wrap coils around my fermenter and used the gotta brew jackets -- jackets are just as effective, probbaly more so.. the only downside to the gotta brew jackets is the pressure limitation they have -- you need to really pay attention to how strong your pump is.. as long as you don't do something silly (like use a gear pump) I think you'll like how they perform/work..

this thread has some good information about using ice/cooler for your cooling source:
https://www.homebrewtalk.com/forum/threads/diy-conical-chilling-temp-control.645826/

tl/dr: I (and others) believe that you can reasonably control ale temps using Ice, but that cold crashing, lager temps, etc would be untenable, and you'll hate changing Ice out after a (very) short time...

 

[RPh_Guy]

Tubing is dirt cheap and I think accomplishes the same goal as a jacket for a lot less money than any jacket I can find so I'll probably go that route.

My calculations show I can hold a 5.5 gal batch at 62F with about 12 lbs of ice (assuming minimal heat transfer from ambient), so 2 frozen gallon jugs (16 lbs) covers the entire fermentation.

It'd take me approximately a quarter pound of ice to cool 1 degree Fahrenheit (if my math is correct). Currently I don't do any cold crashing, so this isn't an issue.

FYI I used 118 kJ/mol glucose as the heat output for fermentation.

 

[RPh_Guy]

No that's not right. I'll look at it later.

 

[RPh_Guy]

Nope, looked at my calculations again. It was right, assuming a 1.060 wort.

118 kJ/mol glucose times 1mol /180g glucose gives kJ/g glucose produced as heat of fermentation
times 1000 J/kJ to convert to Joules
times 163 g/L (in a 1.060 wort)
times 3.785 L/gal
times 5.5 gallons gives Joules produced in my batch throughout fermentation assuming 100% attenuation. = 2,224,000 Joules

Now a little algebra to determine how much energy ice at 32F heated up to 62F can absorb...
Water's heat of fusion = 334 J/g
Liquid water's heat capacity = 4.18 J/(g°C)
Q = mcΔT
(water mass) * 334 J/g + (water mass) * 16°C * 4.18 J/(g°C) = 2,224,000 J
Gives water mass of 5560 grams = about 2 gallons

TL;DR Yeah, on paper ice looks very feasible for maintaining temps. If insulated well enough, maintaining lager temps wouldn't be much more difficult.

 

[JDWebb]

My first cooling system was wrapping copper tubing around the glass carboy and running cold water through it.
Next, I put the tubing in a 48 qt Coleman Cooler, filled the cooler with water, and circulated ice water through the tubing from another cooler.
By this time I was fermenting with 2 stainless steel fermenters with submersible chiller coils, and I circulated ice water from a single cooler.
My next ambition was to get more efficient. I was adding ice every 3 days and it became monotonous so I bought a large Pelican ice chest, now I made my own block ice, and it stayed for 7 days.
After that, I found a used water chiller used for salt water aquariums and hydroponics. Now I could supply cold water, 40ºF cold water from a 15 qt cooler. Works like a glycol system for less than half the cost.
DIY, more pride, home built, home brewing.

 

[Farside]

Ideally you want iced water (with ice chunks in it) not solid ice. If you freeze your coil in a solid block for example (something I've done), it melts the ice in contact with the tube and you're quickly left with an air gap between the ice block and the tube and it stops cooling the wort.

If you have iced water with ice blocks then this doesn't happen. The amount of energy required to transition solid ice to water (32F to 33F) is massive compared to the amount of energy to raise solid ice just 1 degree (25F to 26F). So you are looking for slushy iced water at 32F for optimal cooling.

I found 5 gal of slushy water is enough to cool 5 gal of boiling wort to pitching temperature.

 

[RPh_Guy]

The system I proposed is for keeping fermentation cool, not chilling wort post boil.

 

[yowzers]

I do this essentially, but I bought a rubber stopper that had a stainless loop inserted through the stopper. The stopper fits into a hole I drilled in my bucket lid. I insulate with a blanket, use a 60 GPH fountain pump, and an Inkbird. Works like an absolute charm and I can lager no issues as well. I do go through a 1 liter bottle of ice twice per day, but that's fine with me. I didn't know they sold such a thing as an aquarium cooler, but I guess I could use that and stop using ice altogether.

 

[JDWebb]

I do this essentially, but I bought a rubber stopper that had a stainless loop inserted through the stopper. The stopper fits into a hole I drilled in my bucket lid. I insulate with a blanket, use a 60 GPH fountain pump, and an Inkbird. Works like an absolute charm and I can lager no issues as well. I do go through a 1 liter bottle of ice twice per day, but that's fine with me. I didn't know they sold such a thing as an aquarium cooler, but I guess I could use that and stop using ice altogether.

You can get the water coolers at hydroponics stores also. They use them to water plants because cold water is less susceptible to bacteria that can harm plants. They are expensive, around $400, but half the price of a glycol system.