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Devin

Glycol Systems

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In the planning stages to starting our distillery in Central PA, specing all equipment out and we came across the idea of glycol cooling versus water.  Anyone out there have any info on benefits and costs of systems?  Thanks for helping out!

 

Cheers!

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If you have a lake or well to draw from for your water source then water will be less expensive.  We are in Northern Ohio and we would be paying both the water and sewer charges to cool our equipment which made glycol the best bet.  You haven't said anything about the size of your equipment but since you are asking the question I am assuming it is pretty good size.  For sizing you will need to tell us what you want to cool and then Mike from MG Thermal who frequents this forum would likely be able to tell you what's best.  Another thing to keep in mind is the summer vs winter temp of your water.  We get ours from Lake Erie and in the dead of Winter it is 40 degrees but in the Summer it can get as high a 75 degrees which may not be low enough depending on what you are doing.

Cheers

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Food for thought. We are really new but have already switched over to a hybrid system where we chill one CLT with an internal glycol loop cooled by a chiller and have a second unchilled tank of water that we let cool ambiently to the room. They both pump through the same water lines to our condensor, mash tun, etc. This allows the shop to not run the chiller any more than necessary and retain some hot water to be use for other purposes (in our case simply radiant heat).

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We installed a closed loop system that can be either water or glycol. Right now we're using water. The water is cooled by sending it through a 400' coil which lives at the bottom of a pond about the size of a swimming pool. In the summer when its warm, we can send the hot condenser water directly to the pond heat exchanger/coil. In the winter, we can re-direct the hot water into the radiant floor heating system to warm the tasting room. We run three small stills and a wort chiller this way and so far so good.

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I have used systems in the past which utilize a glycol chiller cooling a water reservoir that in turn cools production.  Spec the BTU you need cooled and then size your water tank to that, add a buffer for thermal ballast.  This can be a cheap poly tank or whatever you can find cheap, the bigger the tank you can afford or accommodate the better.  The water from that tank circulates through cooling condensers and fermenters and back into the tank.  This works with any cooling technology, glycol, ammonia, etc, the extra size creates a built in buffer if your chiller trips off or is temporarily interrupted.  Insulate your reservoir and delivery pipes for efficiency.   

Over time you will def get bio build up in the cooling water, so you will need to look at treating the water with chem that is neutral to your equipment, just ask your boiler water treatment guy.  good luck 

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We are in the building stages, we have the exact system Jake Norris mentions, a glycol chiller cooling a water reservoir.  It made the most financial sense as we do not have room for a cooling tower and are on city water.   It also is supposed to allow us to run with a smaller chiller, using the buffer tank excess cooling capacity verses sizing a much larger and more expensive chiller.  Hopefully it works as designed......I apologize that I do not have real world experience to give you.

 

Adam

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Thanks Tim. We used 1" plastic water pipe.

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The primary use for the buffer tank is the concentration of mash or wort cooling.  When you start the cooling run, without the tank, the heat would overwhelm the chiller causing problems like burning out compressors when water passes through the water circuit at above 75-80F.

If your reservoir gets above 80F constantly, you need more chiller or make smaller runs.

I have photos from a W. CT distillery that shows the concept. Because they have good ambient temps for the winter (constantly below 32F) I added an air glycol cooler which allows power saving from the chiller from Nov to March.

I have another install in Pittsburgh without the air-glycol cooler.

For a 10 T chiller the added air-glycol cooler is an extra $3,500, saves what amounts to 10 HP of power usage during winter months.  I would say this would be worth it near the Finger Lakes (I remember some of those winters).

If needed, I'll walk it though for anyone interested.

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Glycol can be useful for a number of reasons, but also has limits to be aware of.

To clarify things, most Glycol systems as used in Breweries etc. are " OPEN LOOP " systems because the return well is open to and runs at atmospheric pressure. True closed loops such as Building Chill Water loops are closed and the entire system is pressurized as such. They behave differently and require different handling. You can use a straight glycol system and skip the extra complexity of a Glycol to water HX, but your chiller and well have to be oversized and the maths have to be respected. As MG Thermal has stated, ALL FLUID CHILLERS have a MAX return fluid temperature they can tolerate coming in, and as a general rule you really never want that above 85F. Your return fluid temp cannot be allowed to overheat the inlet fluid temp to your chiller HX, so design and correct balance of engineering are critical.

The other point to be made is about attempting to bank BTUs on a recirc system which does not work the way people think it may. If your chiller is undersized, its all a game of load and timings. The only way to truly bank BTUs in a case like this is with one shot usage of the water that is pre-cooled, or an ice bank system. Otherwise the temperatrue of your cooling water will keep rising and never stay consistent and you will have to alter your process to make up for the lack of a static supply of cooling media which does not really make sense for product consistency and a stable process.

With Glycol, your chiller can be outdoors with minimal need for extra freeze protection measures when brix is correct. Glycol does not transfer heat as efficiently as water. Glycol of the correct type does not require any additional chemical treatment to remain stable. Glycol is a challenge to seal with respect to any threaded type fittings due to the surface tension. Because of this facet a lot of shade tree methods for pipe fitting will fail and leak. Glycol is used in Brewery chillers in order to cool vessel contents into the MID 30F range, in which case the chiller setpoint may be 30F or below. Water systems are limited to 40F generally and even then have to be handled carefully control wise. It is not real fun to work with or get your hands in. Dye is generally added to the soultion to make leak detection easier. Mechanical pump seals tend to last longer than with straight water.

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Thank you all for the replies!  I guess I should have been more specific in my post....so here it goes.  We are on city water, no lakes or reservoirs near by.  Plans currently is to purchase a 600 gal Stripping Still and use it as a mash tun then transfer to open top 2 sided jacketed fermenters.  Eventually after stripping run we will go to a 300 gal finishing still.  Thoughts on this system for Glycol chilling units?  MG Thermal we are in Central PA about 20 minutes West of Harrisburg.  Thank you all for your assistance!

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Devin, I've driven through that part of PA many times, taking Rt15 up through to my childhood home in Corning, NY.  

Hope to talk to you soon.

Regards, 

Mike

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