Temperature Controlled 18 Gallon Conical Fermentor for less than $300

[Sudz]

I recently purchased a 15.5g keg with a corny top welded to it, and a hole on the other end for a plug and airlock ($30). The plan (the easy part anyway) is to cut the end with the hole out and weld a cone and legs to it (cost of material only, no cost for welding or passivation, got a connection that loves homebrew)
I have a small window A/C unit ($0) I plan on using to cool the fermentor by wrapping the it with copper tubing ($20) and plumbing it to the A/C unit. Of course there will be 2 temperature wells ($0, I'm a machinist), one for the thermostat($60), another for the thermometer($20). The fermentor will be insulated for out of the house usage. A blow off tube, and possibly an airlock, can easily be connected via a ball lock connector ($4). Plus there will be 2 stainless steel ball valves ($50), and the cost of the A/C service (I hope he likes homebrew)

These are my questions:

What would be the best diameter and length of coil to use on the copper tubing?

Can I use an alternative refrigerant in the window unit as effectively as freon?

Is ther going to be a problem with the A/C unit Freezing up, or will the keg would act sufficiently as an eveporator coil?

Should I put a barrier between the tubing and the keg to prevent a reaction from dissimilar metals, or is this not going to be a problem since the keg is stainless steel?

Any input would be greatly appreciated.

[sallad]

i have no advice to give you on your endeavors, although it sounds quite interesting.

i just wanted to say... is that a racoon humping a beagle???

oh yeah, and welcome aboard!!

[danno]

it sounds like a decent idea, I'd be interested in some pics of your progress. One thing I would seriously consider, get a digital thermostat with both an adjustable differential AND a cycle delay feature. that will avoid compressor damage. You also can avoid putting a separate thermometer in, since the digital controllers can show you actual temp at the push of a button...

I can't help with your plumbing questions, but I don't think you are going to have to worry about the unit freezing up, especially with a 2º or more differential, your on and off cycles will be long enough to keep it from freezing up...

check out www.controlsdepot.com for thermostats, they have both the Ranco ETC111000 and the Johnson A419 for under $50...

oh, and $50 for two SS ball valves? that's kinda pricey, unless you're buying a 1" valve... check out www.northernbrewer.com, they have 1/2" SS valves for $15. if you're looking for something bigger, try www.buyfittingsonline.com. it might be nice, for a fermenter, to go with a 3 piece valve so you can disassemble and clean it...

[O2 Mash]

Originally posted by danno

oh, and $50 for two SS ball valves? that's kinda pricey, unless you're buying a 1" valve... check out www.northernbrewer.com, they have 1/2" SS valves for $15. if you're looking for something bigger, try www.buyfittingsonline.com. it might be nice, for a fermenter, to go with a 3 piece valve so you can disassemble and clean it...

stpats.com has even better pricing on SS valves, but I called buyfittingsonline.com and they matched the price, and they were a pleasure to deal with. I've found stpats.com to have a bit of an attitude problem so she lost the biz :p

[Steve16823]

If I understand your description correctly, you are planning on rerouting the evaporator line from your A/C unit to a copper tubing coil inside or wrapped around your fermenter?

It sounds great, but I think the A/C part will be the weakest link. Any leaks in that condenser line and you'll be spiking your beer with refrigerant, oil, etc.

I've been thinking (dreaming) recently about making a water-cooled fermenter, using either tap water (they do not monitor or charge on water usage in my town) or recirculated water kept cold in a mini-fridge.

[O2 Mash]

Originally posted by Steve16823


I've been thinking (dreaming) recently about making a water-cooled fermenter, using either tap water (they do not monitor or charge on water usage in my town) or recirculated water kept cold in a mini-fridge.

NEW TOY!!!! Nice idea

[Steve16823]

Originally posted by O2 Mash
NEW TOY!!!! Nice idea

Thanks. It seems to me it would be relatively easy, just put a container of water in a mini fridge (as large a container as it would hold), and then rig a pump up to a thermostat to circulate cold water in a coil either wrapped around your (insulated) fermenter or immersed in your wort.

However, jumping back into homebrewing this year full force and buying a kegging system (7 cornys) and a chest freezer, I think my homebrew setup is as complicated and expensive as my wife will currently allow (reference your signature line).



Hmmmm... a corny keg filled with water in my chest freezer would make an excellent cooling source. A small pump, a thermostat, some tubing to coil around my fermenter, wrapped in insulation... rats... I'm probably talking $100 easy...

Heat transfer rates with tubing wrapped around a plastic or glass fermenter would be pretty low, for that matter.

[Sudz]

sallad,
Good Eyes, the caption that goes under that picture is " Winner Of The Worlds Worst Hunting Dog Award". It could happen under the influance of enough homebrew, don't ya think?

danno,
The digital thermostat sounds like a winner, after all, the less welding, and things to clean around inside the fermentor, the better. Thank you for the link.

02 mash,
Thank you for the web addy on the valves. I'll be sure to check that out. I need some valves for my HERMS system, I'm also looking for stainless"quick connects also, do they have the best price on those too?

Steve,
Never fear, I wouldn't think of running another system within my fermentor. With enough tubing around the outside of the keg, I should be able to suck the heat out of it. I also thought about pumping an antifreeze solution through a coil which would sit in a block of ice in the freezer and then flow back into a couple of buckets which the carboys would sit in, housed in an insulated box. granted this would be cheaper, but I currently use the freezer for hops storage and lagering. Not to mention, my wife would be pissed if I used up much more space on the car port :D .

As soon as I get this project wrapped up and take it for a test drive, I'll post some pictures and lay it all out for anyone to duplicate. I'm going to Oregon around the middle of Oct. and plan to start on it seriously when I get back. I'll also include a couple pictures of my HERMS system. It's pretty basic, using a pump and gravity to keep things moving, but the tun and kettles are all 3 CIP. There lies another project, building a hitch mount for my truck for it. The thought process is always at work.
I was doing some reading here on the site last night, and I've come up with another idea for beer storage. I have a 2-door glass front display fridge that I believe is about to take a dive on me and I was considering mounting it to the fridge to make onne great big keggerator. I currently use it for fermenting lagers, and lagering my ales. It really improves the quality and the clarity of my ales. Even my blackest of stouts allows light to pass through. I hold them at a temp of 50f for 3-4 weeks, around 5 weeks if I forget the irish moss. If you've never lagered an ale, try it, you'll be pleased with the results