Using Winter Weather to Cool Beer/Wort

[NS_Nano]

I am up in Canada and the ambient temperature for at least six months of the year is low enough to regulate fermentation, and for at least four months of the year it is lower than a walk in cooler. As such, it seems silly to use electricity (= coal here in NS) to run a glycol system for those tasks. I am considering using one or two storage tanks of glycol or water located outside for wort chilling and fermentation control. For the wort chilling, I envision two tanks located outside with pipes running through the wall, one tank filled and one tank empty. The glycol/water would pump one from tank to the other via the chiller. The hoses would have disconnects to allow them to be switched between batches to reverse the flow. This would save both water and energy (and in the winter would provide a cooling liquid well below ground water temps for super fast chilling). Fermentation temp control could be run in a similar manner, but just recirculating off a single tank (average daily temps are <10 C/50 F for eight months of the year, and with a large reservoir/sufficient thermal mass, daily swings wouldn't really affect things). I have also thought about hooking the walk in area up so outside air is used to cool it during the four months of the year when the average temp is <0 C/32 F (temp. conbtrolled fan and duct).

Wondering if anyone is currently doing any of these? If not, do you see any reason why this would be a bad idea? Brewery size is small: 200 gallon fermenters, one batch per day boil maximum.

Thoughts?

Jason

[foestauf]

That is pretty common in the colder regions. I've seen the walk in cooler hooked up to a motorized valve to just blow in outside air during the cold months.

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[NS_Nano]

Hoping that someone who in employing one or all of these could comment on specifics of their set up, difficulties they've encountered, etc. It seems pretty simple and intuitive, but to the best of my knowledge none of the smaller breweries up here are doing it, which suggests an issue (or else just oversight).

[Starcat]

Free Cooling

This process is known as " Free Cooling " in HVACR circles. It can be implemented a number of ways, but as always it requires calculations to make it work correctly.
You need fan assisted Heat Exchangers to do the job correctly if you are expecting to use air as the heat transfer media.
You still need mechanical chiller redundancy and a control system that can switch between those modes.
Due to Glycol Brix Limitations, I would not want the Glycol holding wells outdoors in this kind of arrangement.
There are some ins, outs, and pitfalls to be avoided there regarding low temp failsafes, loop pump control strategy, bypass, etc.
Doing it correctly will not be cheap, but it can work well.

[TGTimm]

At optimal glycol/water mix of between 24 and 29 Brix, which gives good freeze protection with good thermal capacity, your glycol solution will start to freeze between -15 and -21C. This could be a problem in northern locations with glycol stored outside.

[NS_Nano]

Feedback is appreciated. We're in a freeze thaw climate here, with average daily temps no colder than -5 C, even in February, so a large reservoir of glycol mix should be OK. I am going to try to implement for wort chilling during the colder months as a place to start, and then perhaps go from there. Will provide updates on mickey mouse solutions if things work out.

[mswebb]

We are investigating our options for utilizing the cold ambient temps in our region. Not unusual to be below -20C for much of our winter with extreme temps in the area of -30C to -40C.

While is seems like it should be simple to harness the cold, the systems are generally more complex. Money can be saved over time but it requires significant up front cost to do so. As with many other small businesses, these types of systems are luxuries or "phase-two" projects; not required for operation but nice to have and talk about.

[TGTimm]

Several years ago, I designed and built an "economizer" system that moves cold outside air through our finished product cooler when the temp is ~5F lower outside, and is reversible for times when the cooler gets too cold.

I could post a schematic and parts list when I have time, if anyone's interested.

I understand that such systems are commercially available now, but I couldn't find anything back when I built this. Parts cost for the sensor is ~$10.