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General Category => Kegging and Bottling => Topic started by: phillamb168 on June 29, 2011, 03:10:01 PM

Title: Home Glycol system
Post by: phillamb168 on June 29, 2011, 03:10:01 PM
The living room isn't big enough for more than a 2-keg kegerator, and I want to have more than that available at any time. I figure glycol is a good way to do it, but them things cost $$$$. Has anyone ever done a home-made glycol system? It seems like basically you need a pump that can handle continuous operation, some glycol, a way to cool the glycol, and some pipe insulation and electrical tape, basically. This seems like it would be an excellent DIY project, but I wanted to see if anybody else had done it before...

As an aside, I'm also going to try to machine my own draft tower. Already got the angle grinder, taps and stick welder, so the cost should be way less than the $400 KegWorks wants for a multi-tap glycol-ready tower.

...or am I nuts? I HATE BOTTLING.
Title: Re: Home Glycol system
Post by: dak0415 on June 29, 2011, 03:23:07 PM
How many kegs do you want to have available?  Do you not have chest freezers in France.  Just have a secondary kegerator (fridge) in your brewery that will handle 4 or 5 kegs, and just keep the beer your wife wants to drink in the house.  If you use a stand-up fridge, you won't need a tower.
Title: Re: Home Glycol system
Post by: jeffy on June 29, 2011, 04:58:44 PM
I saw a commercial brewery that had a home made glycol set-up to chill 10 bbl a fermenter.  He had a small freezer with a temp controller in it to regulate the temperature of the glycol and a pump to circulate it to the fermenter.  Pretty cool, I thought, but he has since upgraded.  I don't think it could support more than one fermenter.
Is your idea to put the beer in an adjacent room and run lines to your living room?  If so you could pump cold air through the same tubing you run the beer lines.  I remember seeing a write-up of a project like that once.  I think the beer was on the floor below or in the basement.
Title: Re: Home Glycol system
Post by: tschmidlin on June 29, 2011, 05:29:47 PM
BYO did an article on it a couple of years ago.  I know a guy who built one, but I never saw it.  I haven't been in touch with him in a while and I recently saw he was selling all of his brewing equipment.  No one seems to know what happened, or they're not saying.  :-\

Google has some resources, but I don't know if they are any good.
Title: Re: Home Glycol system
Post by: phillamb168 on June 29, 2011, 05:52:43 PM
Oops, I forgot to specify: this would be going in my basement/wine cellar, which is directly below the living room and stays at a pretty constant 60-65 deg F.

There are chest freezers here, but they're expensive (7 cu ft = 350 euros +) and too big, otherwise I'd put it in the living room with a collar. I'm getting the chest freezer as long as it would be feasible to run the lines up the 10 feet or so from the keg to the dispensing system. The other option is to just keep the kegs sitting in the cellar and chill the beer at the tap like a jockey box. I know you get foam when you take carbonated beer from cold to warm, but what happens in the other thermal direction?

... of course, I suppose I could build a bracket system to mount the keezer to the ceiling of the cellar...  :o ::)
Title: Re: Home Glycol system
Post by: tumarkin on June 29, 2011, 09:48:30 PM
yeah, mount the keezer to the ceiling and the taps could then be mounted on the floor... maybe right next to the couch. just a short run, the beer would stay nice & cold. maybe just use a muffin fan to circulate cold air from the keezer into the tap tower. you wouldn't even need to get up to get a beer. sweet!!! ;D
Title: Re: Home Glycol system
Post by: Joe Sr. on June 29, 2011, 09:57:38 PM
Phil - I ran through the same thought process as you when we remodeled our kitchen a couple years back.

I had full approval to put taps in the kitchen, but couldn't figure a good way to bring the beer up from the basement below.  I did think about suspending a fridge from the ceiling in the basement, but only briefly...

In the end, I decided short trips to the basement for draft beers wasn't too bad of a way to live.  The glycol system seemed to be just too much effort, cost, etc. and the cold plate would have required dedicating some cabinet space to a wine fridge.  Obviously, suspending a fridge from the ceiling of the basement just wasn't practical.

If you get your system worked out, let us know.  I'd love some taps in the attic, as it's a long way to go from there to the basement to get a draft...
Title: Re: Home Glycol system
Post by: lupulin5446 on June 29, 2011, 10:42:50 PM
To glycol cool the lines from your cellar, you will need to put together a 'python', a recirculation pump, a reservoir, and a cooling device.  The cooling device can be a small refrigerator, as you will want your glycol to be only slightly colder than your beer.  The Inner diameter of the coolant line should be larger than your draft lines to avoid burning up your pump.  To construct your 'python', simply loop your coolant line so that the intake and return portions run parallel, but end at the same point.  Lay out your draft lines parallel to the coolant lines, and attach threaded fittings to both ends.  Wrap the whole assembly into 1 bundled cable with insulated tape.  If you can not find it, try finding a more generic insulation, and wrap it in uninsulated tape.  Be sure to give yourself some extra length when constructing your python.  Place the reservoir inside the cooler and recirculate the glycol.  To clean the draft lines, link them in series with fittings, turn off the glycol pump, and recirculate hot caustic. 

An issue you must consider when pushing beer up from a cellar is the head pressure in your kegs.  You will be fighting both gravity, and the friction in your draft lines.  If you use your normal pressure settings, you will likely notice a greatly decreased flow rate.  Increasing the head pressure will over carbonate most of your beers, so your only option would be to use draft lines with a larger diameter because of the lower friction coefficient.  Unless, of course, you want to use mixed gas.  You should note that the glycol lines will keep your beer cool on its journey to your glass, but will not effectively cool warm beer.

I hope this is helpful.
Title: Re: Home Glycol system
Post by: phillamb168 on June 30, 2011, 09:25:30 AM
To glycol cool the lines from your cellar, you will need to put together a 'python', a recirculation pump, a reservoir, and a cooling device.  The cooling device can be a small refrigerator, as you will want your glycol to be only slightly colder than your beer.  The Inner diameter of the coolant line should be larger than your draft lines to avoid burning up your pump.  To construct your 'python', simply loop your coolant line so that the intake and return portions run parallel, but end at the same point.  Lay out your draft lines parallel to the coolant lines, and attach threaded fittings to both ends.  Wrap the whole assembly into 1 bundled cable with insulated tape.  If you can not find it, try finding a more generic insulation, and wrap it in uninsulated tape.  Be sure to give yourself some extra length when constructing your python.  Place the reservoir inside the cooler and recirculate the glycol.  To clean the draft lines, link them in series with fittings, turn off the glycol pump, and recirculate hot caustic. 

An issue you must consider when pushing beer up from a cellar is the head pressure in your kegs.  You will be fighting both gravity, and the friction in your draft lines.  If you use your normal pressure settings, you will likely notice a greatly decreased flow rate.  Increasing the head pressure will over carbonate most of your beers, so your only option would be to use draft lines with a larger diameter because of the lower friction coefficient.  Unless, of course, you want to use mixed gas.  You should note that the glycol lines will keep your beer cool on its journey to your glass, but will not effectively cool warm beer.

I hope this is helpful.

Could I not keep the reservoir in the same keezer as the kegs? I'm guessing I can run the glycol through some 1/2" ID food-grade tubing? Or does it need something larger/different tubing type? And in terms of the pump, can I use a regular March pump (or a large aquarium pump), or does it need to be something special?

The build seems simple in principle - it's basically a radiator, right?

Pump and tubing costs I can reckon, but how much does glycol cost, and how much might I need? 2-3 gallons? And it HAS to be polypropylene glycol, right? Aaaand finally - could I just use a 1/2 water, 1/2 cheap vodka mixture? Glycol is basically alcohol with an extra OH-group (yes, I know this makes it entirely different) but they both share the ability to be chilled below freezing and still remain liquid.

Where's da Weaze - I thought he used to be an HVAC guy.

--

In terms of pushing the beer, most commercial bars go at minimum the distance I'm going from cellar to living room, so how do they get the beer up there without over-carbing it? Could I use a pressure regulator to vent excess CO2 between dispensing? Other than using beer engines, of course, but I'd prefer to use my existing taps if possible.
Title: Re: Home Glycol system
Post by: tom on June 30, 2011, 05:18:55 PM
I would think that keeping a water tank in the fridge would be the most economical.  Water actually works better than glycol.  They just add glycol to be able to get the temp below freezing.

For the balancing, you will still carbonate to your desired carbonation volumes and adjust the serving line resistance to "balance" the system.  You'll probably use some 1/4"  ID hose in the beginning of the line and just enough 3/16 ID at the end to balance.
Title: Re: Home Glycol system
Post by: tschmidlin on June 30, 2011, 05:38:58 PM
In terms of pushing the beer, most commercial bars go at minimum the distance I'm going from cellar to living room, so how do they get the beer up there without over-carbing it? Could I use a pressure regulator to vent excess CO2 between dispensing? Other than using beer engines, of course, but I'd prefer to use my existing taps if possible.
They use either bigger tubes (1/4" or bigger like Tom mentioned above) to cut the resistance so you can serve at the same pressure as you carbonate with, or they use mixed gas.  N2 is about 80 times less soluble in beer than CO2 is, so using a blend of gases can let you push a long way without over carbonating the beer.  Unless you have some place near you that does custom gas blends, I think a larger tube is the way to go.

Assume you're going up 12 feet . . . 144 inches, Jeff R pointed out in another thread that 1 psi will raise a column 27 inches, so 5.3 psi to overcome that.  If you carb at 12 psi, that leaves 6.7 psi for the hose.  So you want a hose that gives you 0.56 psi resistance per foot.  morebeer's 5/16" says 0.40 lbs per foot, the 1/4" says 0.65 lbs per foot.  You can pick one and tweak the carb pressure/temp, and of course the actual height might be a couple of feet different.  I'd start with figuring out the height.
Title: Re: Home Glycol system
Post by: lupulin5446 on June 30, 2011, 10:11:30 PM
In terms of pushing the beer, most commercial bars go at minimum the distance I'm going from cellar to living room, so how do they get the beer up there without over-carbing it? Could I use a pressure regulator to vent excess CO2 between dispensing? Other than using beer engines, of course, but I'd prefer to use my existing taps if possible.
They use either bigger tubes (1/4" or bigger like Tom mentioned above) to cut the resistance so you can serve at the same pressure as you carbonate with, or they use mixed gas.  N2 is about 80 times less soluble in beer than CO2 is, so using a blend of gases can let you push a long way without over carbonating the beer.  Unless you have some place near you that does custom gas blends, I think a larger tube is the way to go.

Assume you're going up 12 feet . . . 144 inches, Jeff R pointed out in another thread that 1 psi will raise a column 27 inches, so 5.3 psi to overcome that.  If you carb at 12 psi, that leaves 6.7 psi for the hose.  So you want a hose that gives you 0.56 psi resistance per foot.  morebeer's 5/16" says 0.40 lbs per foot, the 1/4" says 0.65 lbs per foot.  You can pick one and tweak the carb pressure/temp, and of course the actual height might be a couple of feet different.  I'd start with figuring out the height.

A hose that gives 0.56 psi resistance per foot based on a 12 foot hose would make the liquid static at the top of the draft tower.  Even 0.40 psi/foot would give a slow flow rate.  I would guess that 3/8 I.D. would be minimum, and perhaps restrict it to a smaller size for the last 4-6 inches.  Another option is to elevate the freezer as close as possible to the ceiling without making keg changing too cumbersome.

BTW, it would be more efficient to keep the coolant reservoir with the kegs, but I recommended keeping the coolant a bit cooler because there will always be some heat loss in the python, which can lead to foaming.  Restricting the draft lines at the end can help combat foaming though.
Title: Re: Home Glycol system
Post by: tschmidlin on June 30, 2011, 10:24:10 PM
A hose that gives 0.56 psi resistance per foot based on a 12 foot hose would make the liquid static at the top of the draft tower.  Even 0.40 psi/foot would give a slow flow rate.
Systems are typically balanced so that the pressure at the tap is zero.  According to the draft beer quality manual (https://files.pbworks.com/download/XQ1BY0qBgv/draftquality/18182336/DBQM_Full.pdf) "When applied pressure equals resistance, a draught system will pour clear-flowing beer at the rate of 2 ounces per second."

He needs to take into account the resistance of the components in the tower, the faucet, etc, but ultimately he's still shooting for zero at the tap.
Title: Re: Home Glycol system
Post by: lupulin5446 on June 30, 2011, 11:46:12 PM
It seems your knowledge of Newtonian physics may be lacking...If pressure on the liquid is equal to the total resistance, then there can be no flow.  The only way you can get liquid to flow this way is if you have gravity on your side.  If the volume of liquid is above the spout on the tap, then gravity would cause the liquid to flow out (like a siphon).  If the mass of liquid is below the spout, than nothing will happen.  The only other thing that would cause the beer to flow if the pressure at the spout is 0, is the decarbonization of the beer.  An open spout will cause a pressure drop that will drive an excessive amount of CO2 out of solution, resulting in a steady flow of beer, and a glass full of foam.
Title: Re: Home Glycol system
Post by: tschmidlin on July 01, 2011, 02:30:27 AM
I understand physics pretty well, thanks, but it is hard to argue with results.  If you don't believe the Draft Beer Quality Manual (https://files.pbworks.com/download/XQ1BY0qBgv/draftquality/18182336/DBQM_Full.pdf), published by the Brewers Association, that's cool with me.  No one is ever required to believe someone just because they are an authority on the subject (not me, the BA).  But the nice thing is you can always try it yourself and see what happens.

I suspect one of the reasons it works is that they use some rounding and the tubing resistance numbers you get are usually high.  For example, the DBQM says to allow 0.5 psi per foot of height, which is high (for water at 62F it's 0.433 lbs/ft).  And morebeer says their PVC tubing has a resistance of 2.2 lbs/ft, which in my experience is too high.

So unless you are actually going to go to the trouble of measuring the resistance in your system, you can go by the guidelines provided by the parts suppliers and shoot for zero at the taps and get a good pour.  I've found it is best to start with an even longer line than calculated and cut it back until you get the pour you want.

If you wanted to, from there you can add a hose to the end of the faucet and see how high the beer rises in it, then back calculate the actual pressure at the tap.  But that is just an exercise that would only be useful in the future if you had perfect knowledge of the resistance of every component.  Physics only works if you can plug in the right numbers.

@Phil - don't forget to account for the actual length of the line, not just the rise.   You'll want at least a few feet in the cooler to make it easier to tap kegs.
Title: Re: Home Glycol system
Post by: oscarvan on July 01, 2011, 06:18:27 AM
Have you considered using, say, something like small flexible HVAC ducting and a computer fan? Run a loop, and put the computer fan in the return end creating suction..... Put the beer hoses in the first half. You'd have to put a collar on the freezer, and do some fabrication, maybe not the most energy efficient way, but a lot less hassle.
Title: Re: Home Glycol system
Post by: phillamb168 on July 01, 2011, 08:59:48 AM
Have you considered using, say, something like small flexible HVAC ducting and a computer fan? Run a loop, and put the computer fan in the return end creating suction..... Put the beer hoses in the first half. You'd have to put a collar on the freezer, and do some fabrication, maybe not the most energy efficient way, but a lot less hassle.

The space I'll be running this through would prohibit most HVAC-size duct work (we're talking the 6" + flexible stuff right?). Ideally, the cable diameter would be no more than 3-4 inches. I like the idea, though, because as you said, way less work..

Back to pumping the fluid, can I use a strong aquarium pump submerged in whatever liquid I end up going with?

I'll be measuring the total distance this weekend. The cheaper I can make this, the happier my wife will be, so I think I may try just a water-based system at first, changing it to something else later if need be.

How feasible/efficient would it be to use a thermoelectric element to cool the liquid? Keeping the liquid container out of the keezer would free up valuable space :-)

.... Of course.... now that I think about it... In theory I could rig up jacketed glycol coolers for all the kegs I want to serve, and not have to use a keezer at all, right?
Title: Re: Home Glycol system
Post by: lupulin5446 on July 02, 2011, 06:12:21 AM
Ahh, thermo-electrics...I first became familiar with the technology when it was restricted to military/NASA use.  Thermo-electrics hold great potential for efficient heat exchange, but unfortunately, it is only really practical when the temperature difference is large.  I.E. Thermo-electrics are great at changing a volume from 80c to 10c, but lose efficiency when it comes to maintaining temperatures.  The less the difference between the target volume and the outside temperature, the less efficient it becomes.  The great benefit from thermo-electrics is that the coolant system requires no moving parts other than fans that circulate the air.  Thermo-electric systems often cost more than standard refrigerators, even though they are more efficient over time.  You will lose a bit of heat in the python, so you may want the coolant to be a bit colder.  What you do not want is an 'open system'.  If your head pressure in your kegs does not overcome friction and gravity with a positive value, than you are losing carbonation as you pour.  If you only pour 1 glass at a time, with a reasonable time between pours to build up pressure, than everything will be fine, if not you will lose carbonation on the total volume, and with each beer poured, the foaming will get worse.  BTW, the cool thing about thermo-electrics is that if things are reversed...Heat on 1 side and cool on the other...electricity is generated.
Title: Re: Home Glycol system
Post by: phillamb168 on July 04, 2011, 02:39:50 PM
Does anyone have experience with this:

http://www.ebay.co.uk/itm/BEER-COOLER-SCOTSMAN-INTERCOOL-30-10-COIL-INTEGRAL-/250581087702?pt=UK_BOI_Restaurant_RL&hash=item3a57cbf5d6

Is this something I could use instead of jerrying something?
Title: Re: Home Glycol system
Post by: oscarvan on July 04, 2011, 02:48:52 PM
You sure ten lines is enough?  ;D I suspect the energy bill on that can be substantial.....and it's large.
Title: Re: Home Glycol system
Post by: phillamb168 on July 04, 2011, 03:03:49 PM
Was posted as an example  ;)

They have smaller systems available, it's more just to see what people think.

What I'm leaning towards now is the following:

No fridge. Take a glycol/water pump with the reservoir in a fridge and the johnson temp control probe shoved into the return tube for the glycol. Two pumps would control the following:

1. pump for circulating coolant upstairs for line cooling

and then, the second pump (the idea here is to avoid buying a fridge)

EITHER:

2.A.) glycol out to copper lines wrapping around the outside of each corny, then wrap that whole thing in a jacket of insulation (or perhaps neoprene + insulation? I can get these: http://shop.humle.se/se/art/forty-below-fatstrumpa-stor-till-1819-litersfat-gul.php?grp=295209).

2.B.) build a 'walk-in' that's basically a big box with a lid to fit all the cornys inside, line the box sides and bottom with copper and insulation, have a couple CPU fans to blow things around a bit.

This way I only have to buy a couple new pumps, and therefore avoid having to pay for a new freezer.

Thoughts?
Title: Re: Home Glycol system
Post by: tschmidlin on July 04, 2011, 06:17:12 PM
I think you should price out both options - by the time you buy the extra pump, copper line, glycol, insulation, etc and all of the materials to build your 'walk-in', it might turn out to be cheaper to just buy a freezer and go with the original plan.

For me the freezer makes more sense in terms of simplicity, but that's me.  I know it's 350+ euros, but those keg parkas are over 40 euros each.  That will all add up pretty quickly.

Thanks for the link though, I hadn't seen those keg parkas - I might need to get one or two. :)
Title: Re: Home Glycol system
Post by: phillamb168 on July 05, 2011, 12:00:39 PM
Waiting to hear back from a guy in the UK about a "mini remote cooler" which is the little brother of the guy I posted up top. Apparently you don't have to cool the kegs themselves, as long as they're around cellar temp. The beer lines get hooked up to john guest fittings and the get pushed through stainless steel coil which is immersed in glycol, then pushed through an insulated sleeve with the glycol feed and return. Super, super, super to install, just drill yer holes and bracket the python to the wall so it doesn't fall.

The cost is most likely going to be cheaper than doing it myself by building a keezer, etc - probably around 500-600 euros... We'll see.
Title: Re: Home Glycol system
Post by: oscarvan on July 05, 2011, 03:12:35 PM
Basically a permanent jockey box.....
Title: Re: Home Glycol system
Post by: phillamb168 on July 05, 2011, 03:36:19 PM
Basically a permanent jockey box.....

Exactly... It seems super simple, which means less chance for failure.
Title: Re: Home Glycol system
Post by: phillamb168 on July 07, 2011, 09:41:31 AM
Heard back from the guy yesterday. A 5-line system with everything I need save the regulators is ~£500 including shipping. Not too bad, considering a fridge large enough for 5 kegs would run me about 400 euros.

Pic:

(http://philliplamb.com/glycol.png)
Title: Re: Home Glycol system
Post by: oscarvan on July 08, 2011, 09:33:15 PM
Well, it would indeed be the schnitz if you installed a professional bar system in your house...... ;D
Title: Re: Home Glycol system
Post by: Thirsty_Monk on July 17, 2011, 04:52:32 PM
I know conversation moved on but you could use a beer pump to deliver beer longer distances without overcarbonating beer.
Title: Re: Home Glycol system
Post by: phillamb168 on July 18, 2011, 11:51:43 AM
I know conversation moved on but you could use a beer pump to deliver beer longer distances without overcarbonating beer.

Beer pump meaning beer engine?
Title: Re: Home Glycol system
Post by: jeffy on July 18, 2011, 12:28:55 PM
I know conversation moved on but you could use a beer pump to deliver beer longer distances without overcarbonating beer.

Beer pump meaning beer engine?
He's talking about an electric pump.  Some brewpubs use them instead of CO2 to push beer when the serving tank is a good distance from the tap.
Title: Re: Home Glycol system
Post by: phillamb168 on July 18, 2011, 12:40:32 PM
I know conversation moved on but you could use a beer pump to deliver beer longer distances without overcarbonating beer.

Beer pump meaning beer engine?
He's talking about an electric pump.  Some brewpubs use them instead of CO2 to push beer when the serving tank is a good distance from the tap.

Ah, hrm. If I were doing a real bar, yeah, why not - but I'd be worried about the pump getting sticky because I'd only be pulling a pint or two per day.
Title: Re: Home Glycol system
Post by: oscarvan on July 18, 2011, 04:21:20 PM
I know conversation moved on but you could use a beer pump to deliver beer longer distances without overcarbonating beer.

Beer pump meaning beer engine?
He's talking about an electric pump.  Some brewpubs use them instead of CO2 to push beer when the serving tank is a good distance from the tap.

Ah, hrm. If I were doing a real bar, yeah, why not - but I'd be worried about the pump getting sticky because I'd only be pulling a pint or two per day.

Well, you'll just have to drink more.
Title: Re: Home Glycol system
Post by: Will's Swill on July 19, 2011, 11:52:01 PM
Not everyone has as capable of a liver as you.  ;)
Title: Re: Home Glycol system
Post by: Thirsty_Monk on July 20, 2011, 02:56:10 AM
I know conversation moved on but you could use a beer pump to deliver beer longer distances without overcarbonating beer.

Beer pump meaning beer engine?
He's talking about an electric pump.  Some brewpubs use them instead of CO2 to push beer when the serving tank is a good distance from the tap.

Ah, hrm. If I were doing a real bar, yeah, why not - but I'd be worried about the pump getting sticky because I'd only be pulling a pint or two per day.
I do not think it will get sticky.
Your beer line inside does not get sticky.
May be better solution for you is to have bigger ID beer lines.
Title: Re: Home Glycol system
Post by: timo on August 04, 2011, 04:39:11 PM
I recall seeing this a while back. This is a DIY system that doesn't take a rocket scientist to figure out.

Tim O

http://forum.northernbrewer.com/viewtopic.php?f=29&t=42735&hilit=+GLYCOL+SYSTEM
Title: Re: Home Glycol system
Post by: rob_f on August 05, 2011, 01:51:14 AM
I've done what the OP is asking about.  I have a two-gallon bucket of propylene glycol in a small chest freezer along with frozen food.  A small pond pump is submerged in the glycol and supply and return tubes run out of the freezer and into the kegerator, where they are joined by 4 beer lines in a trunk line purchased from Micromatic.  The trunk line travels about 20 feet and through a wall to the taps in my basement bar.  The beer tubing in the trunk line is barrier tubing with very low resistance.

You cannot have the glycol reservoir in your kegerator.  The heat generated by the pump will always maintain the glycol temperature above the surrounding freezer temperature--the temperature of your beer.  This system has been in service for almost a year and I'm happy with it.  The temperature in my glycol bucket is around 32F (the freezer is at -10F)
Title: Re: Home Glycol system
Post by: phillamb168 on August 08, 2011, 09:51:20 AM
@rob what was the parts cost like on that? Sounds pretty reasonable... And way cheaper than the 800 eur I was going to spend on the machine.
Title: Re: Home Glycol system
Post by: rob_f on August 12, 2011, 02:14:45 AM
The expenses related just to the glycol system were
additional freezer (serves double duty with frozen food),   $200
trunk line, 20-ft                                                            $350
pond pump for the gycol.                                               $ 30
propylene glycol, 2 gal                                                  $ 20
wood collar on freezer                                                   $ 40

So that's $540, but since we keep a lot of frozen food in the freezer, that $200 shouldn't really count.

With my small glycol reservoir, the glycol doesn't have much residence time, so I get a temperature much higher than the freezer temperature.  If I wanted a lower glycol temperature, I would just use a bigger bucket and more glycol.