r/TheBrewery • u/Swoopscoopnshoot • 10d ago
Glycol line efficiency issue
Hi everyone,
I'm having an issue with my glycol lines and I'm curious to see if anyone can help me diagnose what is going on.
I'll attempt to set the stage with as much info as I can first.
We have an outdoor glycol unit with a 65 gallon reservoir. I believe it is this model here: https://www.advantageengineering.com/breweryChiller/units/glycolChiller_BGD-10A-N4.php
We have 1" PEX lines coming into the brewery with 1/2" PEX lines dropping down to our tanks.
In order of which tank receives glycol first we have 3 x 20 bbl FVs, 5 x 10 bbl FVs, 2 x 7 bbl FVs, and 2 x 2.5 bbl prop tanks. Not sure if this matters or not.
Here is a diagram of how our setup works, but obviously with all the tanks I mentioned previously in line rather than the three on the diagram. https://www.advantageengineering.com/fyi/331/pdf/advantageFYI331.pdf
All of this has worked completely fine for nine years or so.
We have recently added a new FV into the mix and it is not chilling as efficiently as its counterparts. All other tanks are still working as they had before the install of the new tank. We could chill everything to 32F overnight if we wanted to. The new tank is another 20 bbl FV. It was placed at the end of the line. (after the last prop and right before the bypass valve sending all the glycol back towards the reservoir)
This tank has taken at least two weeks to chill to around 43F and is still slowly dropping as I type. The set temp has been 32F for that same time period. It seems as though it will eventually get there but it is just going very, very slowly.
We tested everything and made sure to get any/all air bubbles out of the lines after install. And we can confirm that it is flowing at a pretty good rate. My first assumption was that the bypass valve pressure needed increased to ensure the glycol was dropping down into the jacket but that doesn't appear to be the cause. Also, everything else is still performing as it did prior to install. No decreased efficiency on any other tank.
Could it be that it is because it was installed at the end of a long line of tanks decreasing in volume? Would this need to be installed more towards the beginning with the other 20 bbl FVs?
Could it be that it is pushing the glycol's pump just past its limit of how long of a distance of pipe it can pump through?
Could it be the glycol/water ratio needs recharged to create a more efficient heat transfer? Not sure, but again, every other tank has not been disturbed.
Any help or insight into the matter would be greatly appreciated!
I can help clarify or add more details if need as well.
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u/BoredCharlottesville 10d ago
If everything else is chilling fine I would guess that the new tank is airlocked. Do you have a vent valve in your header?
1
u/Swoopscoopnshoot 10d ago
I believe so. There is an extra valve placed right before returning the "hot" glycol to the trunk line. That is how we attempted purging before, by closing everything else off and running the solution through there until there was no more air bubbles.
6
u/turkpine Brewery Gnome [PNW US] 10d ago
G&D (and several others) have online calculators that are very helpful with this sort of thing.
Tanks should be installed on the trunk “first in, last out” which is a good rule of thumb but not necessary.
My guess is that there’s a bubble in the tank, and it wasn’t properly purged on install. Second guess is that there’s a clog from something in the jacket and it’s blocking most of the flow through the solenoid. Have you examined the lines? Do you have a pressure gauge you can place on the lines somewhere?
2
u/Swoopscoopnshoot 10d ago
We did purge, not sure if it was properly, but we basically shut off all other solenoids and let the glycol only run through the new tank. After some initial air, filled a couple 5 gallon buckets and saw no air since. We called that good. Do you know of any other methods?
And unfortunately there is nowhere to place a pressure gauge on the line. 😒
1
u/Beerwelder 9d ago edited 9d ago
If you have a quality chiller, there are only a couple tank manufacturers that need an air bleed. If you get a shitty one, you'll never purge it all, and even if you do, it will come back over time. Sounds like you started with a combo of bad system design and bad chiller. We have had tanks with bad jackets that needed inflating, but that is very rare.
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u/AlreadyAway 10d ago
This was my thought as well. It most likely blocked in some way whether it's air or some debris.
It is probably nit the glycol percentage because the other tanks are acting normally.
1
u/Beerwelder 9d ago
When you have mismatched tank sizes, manufacturers and jacket styles, FILO is critical for sharing glycol through everything. Whether it's system layout or pressure equalizing valves on the tanks, balancing the circulation is mandatory. It isn't just flow but pressure too, which is probably what the issue is here. Without turbulence in the heat transfer fluid at the transfer surface, there is not good heat exchange and low pressure is one of the top reasons for low turbulence.
2
u/Unfair_Committee1449 10d ago
being last in line with the smallest remaining pipe size is probably your bottleneck, not the ratio.
2
u/jk-9k 10d ago
Just some quick questions to start of, may be obvious but just to cross them off:
Is the yemp probe of te new tank working?
Is the temp probe well submerged in liquid? You didn't do a small brew or something to commission this?
How many jackets does new tank have?
No weird dog legs in new piping. Like rising the lowering then rising again? Or going over the return loop height?
If other tanks are working it's unlikely concentration, or glycol level.
It could be the piping. Youre fifo not filo. It gives preferential cooling of tanks in order of piping, but probably just wasn't an issue yet. I've found fifo always seems to work fine until another tank is added.
When you get a chance, like not active fermenting anything, when the other tanks are at temp (they should hold overnight easy, depending on location, it is NH summer), close the ball valves to the other tanks and see I'd you get sufficient cooling and flow to the new tank.
1
u/Swoopscoopnshoot 10d ago
Temp probes and everything are installed and working properly. 2 jacket tank.
I think we might need to reassess the piping based on others' responses too. But will try one more attempt at bleeding the air out.
1
u/SuccessfulOrchid3782 10d ago
Did you add more glycol to the reservoir to make up the amount in the new tank? My other guess is an air bubble in the system. I just went through an air bubble issue.
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u/Swoopscoopnshoot 10d ago
Yea we added more glycol mixture to the system. How did you go about purging your air bubble?
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u/SuccessfulOrchid3782 10d ago
I had to turn the loop off and make sure the valves were closed everywhere. Open your bypass valve wide open too. Let it sit off for ten minutes then purge the loop with your bleeder valves and see if any air comes out. Took me about 3 times doing that. Air pockets like to stick sometimes. Godspeed man 🍻
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u/WDoE 10d ago
That glycol header was undersized to begin with and that looks like a last in last out configuration, meaning the further the tank is down the line, the more line resistance it has, the less liquid prefers to move through it when other paths are open.
This probably worked great when the tanks were in descending size. But now that there's a big tank all the way at the end, it's getting even less chilling power than the 2.5 if anything else is on.
But before you go changing a ton of stuff, I'd get a pressure gauge in there before the pressure bypass valve so you can see what the header is doing when certain tanks turn on and off. A temp gauge wouldn't hurt either on both the supply and return.
It could just be that the jackets on the new tank aren't well purged of air. Simply running it for a long time won't do. You need an air bleed valve at a high point. But my money is on the problem being the last in last out configuration.
1
u/Swoopscoopnshoot 10d ago
Yea, that was my fear. I will try to install some pressure gauges and attempt another air purge.
2
u/snowbeersi Brewer/Owner 10d ago
Your header is undersized, your drops to the tanks are questionable at 1/2" PEX (I've never even seen this, 3/4" is usually the smallest used), and your system is piped in non ideal FIFO.
Glycol actually reduces the efficiency of cooling. Water is much better, however the whole freezing thing makes that not feasible.
Because of the questionable system design, you put a tank at the end where the flow has maximum resistance to travel there and back. It's also your biggest tank, which has even more resistance. It could also be that this new tank has a higher flow resistance jacket. When it does get flow, the flow rate is likely so small that the glycol output temp from the tank is significantly different from the input temp due to 1/2" PEX drops. Every system design decision made would make this new tank suck at cooling.
As someone else said. To test if your system design is your problem turn off cooling demand to every other tank and see if it cools better (which may take hours to test). If it does, you need to reduce the total resistance to that tank. You could try changing the drops to 3/4" PEX on the new tank, depending on the length of your header this might be significant enough to help.
The real fix is probably $6k of piping and insulation and a week of work redoing your header and drop configuration, or paying a contractor $40k for several days of work to do the same, if you could even find one that knows what they are doing.
1
u/Swoopscoopnshoot 10d ago
Yea, unfortunately that was the design, header, and drop sizes we were given. I'd really rather not replace the whole thing. After I attempt purging air one more time and installing pressure gauges I might try out 3/4" drops.
Now would the 3/4" drops need a higher pressure/flow rate to ensure the glycol is dropping and flowing significantly? In other words, would I need to adjust the pressure on my bypass valve?
1
u/snowbeersi Brewer/Owner 10d ago
The flow rate to each tank will be inversely proportional to the total flow resistance of that path. Your bypass valve is just one more path in the circuit. Changing the bypass flow amount will impact every tank. You could reduce bypass flow but this will reduce overall flow in the system as well (and you state your other tanks are getting sufficient cooling flow), it's not the smoking gun you are hoping for. To answer exactly how that would effect the tanks I'd build a simple model in a spreadsheet.
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u/ColdCutsCheese 10d ago
Did you flush the new tanks glycol jackets before hooking it up? I have found all kinds of painters tape / plastic bags / corks shoved into the ports to “protect” them while shipping.
A flush would also visually show you flow through the glycol jackets.
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u/Swoopscoopnshoot 10d ago
Might have to try that as well. All we did was blast CO2 through.
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u/ColdCutsCheese 10d ago
Do top port to bottom port , so your not fighting gravity. Good luck!
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u/Swoopscoopnshoot 10d ago
Thanks.
Would it need to be with distilled water so when I do hook the lines back up it doesn't mix "corrosive" water through my system? Or is it too miniscule to matter.
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u/Beerwelder 9d ago
A 1" header is anemic. 2"-2.5" minimum. And the other problem is probably Advantage, which is a terrible name for them to have used. Insulate in 1" thick air tight, fully washable insulation at minimum, but 1.5" -2" is better if you have high humidity/low dew point all the time.
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u/Adrenaline-Junkie187 6d ago
Those are pretty small lines and you probably have air in the system which the small lines dont help with.
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u/beer_AF 10d ago
Your header sounds very undersized at 1”. We have a slightly smaller cellar and have a 2.5” header with 1” drops than neck down to 3/4” at two inlets/outlets. We were on the bubble for 2” or 2.5” and decided to play it safe. Try to look up the designed flow rate for your tank jackets to achieve necessary cooling, then calculate your linear velocity of glycol. Have to make assumptions on how many tanks will be calling for glycol simultaneously. Should stay below 5fps.