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Thread: Glycol System Specs.....

  1. #1
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    Glycol System Specs.....

    Howdy Hi All,
    I'm looking at replacing our existing glycol system for increased effciency. What parameters (pump pressure, pipe diameter, pipe height, valve/solenoids) must be in a quality install of a new glycol system for a 10bbl brewhouse with 5 FV and 5 SVs?

  2. #2
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    Just some thoughts..........

    I did this upgrade back in '01 on our first Brewery. We originally had separate pumps, reservior, etc. and it was terribley inefficient. Not to plug a sponsor (maybe I should?), but the folks at Pro Refrigeration (a sponsor to this site) were awesome working with me to specify a central chiller unit that would meet our requirements. The unit has operated flawlessly since installation and sits outside behind the Brewery wall. If you want efficient, their unit is all that.

    Our first is a 7 Bbl Brewery with (2) FVs and (3) unjacketted Grundies. We do not have a 2nd stage assist on the heat exchanger. I ran 1.5" DIA copper pipe for all of it (thousands of sweat joints, it seemed). If I were to do that over, I would have run PVD for most of it with copper in damageable areas.

    Our second is a 15 Bbl rig, and we are just finishing the installation of the piece of crap that came with the system when we bought it used. The compressor on that one is a 3 hp (3 Ph) with a 1 hp process pump and a .75 Hp re-circulation pump. They are both Goulds NPE pumps and are 3 Ph as well. The Goulds pump specs can be found on their website, but the "sweat spot" for the 1" is somewhere in the range of 30 GPM at 70 Ft of Total Dynamic Head (with a 4.75" DIA impellor). The pump is working at 53% effiiciency at that point, and you can do no more for efficiency. The pumps are centrifugal with stainless bodies and impellors.

    In the 15 Bbl house, I ran 2" DIA PVC everywhere except for a 1" loop that goes out to feed the 2nd stage assist on the heat exchanger. The reservior is 300 gallons.

    The solenoid size is generally determined from the Glycol In/Out prots on your tanks, but I've seen 40 Bbl tanks with 3/4" solenoids on them, which is what I' recommend. Get the ASCO Red-Hat series (from Granger or similar) and please hear me when I say get the solenoids with ZERO pressure differential. Otherwise, you'll end up burning the coil out when they won't lift on the tail end of your glycol circuit. It was a hard lesson I learned that cost us a lot of jing . Red-Hats are pretty much the standard, and a general purpose solenoid will do fine. Just remember that zero differential! (You owe me a fee already for that nugget).

    Only run your pipes as high as you have to go to get to the solenoids / ports. Insulate everything or learn to love condensate (and mold). Put a ball valve just ahead of the solenoid and on the outflow of the jacket so you can isolate it for maintanence and replace the solenoid without losing your glycol. Also, run your system as a "first in, last out" system to prevent short circuiting of the Glycol in your mains. The first tank to see Glycol in teh Supply Main should be the furthest away from the reservior in the Return Main and the last to drain. This takes a little finesse when doing your pipe runs.........especially if you have long and spread out tank spacings with unique tanks.

    Put a Pressure Relief Valve in the system. Coming off the pump, you should have a Pressure Reducing Vlalve set to around 15 psi to prevent the jackets from splitting unless the manufacturer has stated you can go higher. I install a redundant Pressure Relief Valve in the circuit at the end that dumps to the Glycol Return Main just in case the primary fails. Cheap insurance, really.

    Install a rotary indicator or similar, a pressure gage on the Supply Main side coming out of the reservoir or chiller just ahead of your first tank, and thermometers or temp sensors on the Supply and Return Mains. Place them within a very close proximity for one stop visualization. If something goes amiss, it's great to have a little telemetry to look at to tell you "Houston, we have a problem.".

    Set your Glycol mix level somewhere at the 38% - 40% by volume range and get a couple of Propylene Glycol hydrometers (anti-freeze hydros won't work.....that's ethylene glycol..........mmmmmmmm.....sweet tasting). You should be protecting to somewhere between 0F and -10F. Check it regularly..........every 3 - 6 months. Pro Refrigeration recommends a 34% by volume in their systems (they are safegaurded for freeze-up). A "pieced in" system isn't as failsafe by nature (and the fact that they're sometimes homebuilt) and running the mix a little higher prevents freezing in the line.

    There are other safeguards, like placing a flow control switch between the re-circ pump and the R-22 / Glycol Heat Exchanger to prevent stopped flow from allowing freezing glycol in the Exchanger from splitting the Exhanger open and costing you $2,500 to get a new one. The Flow Controller is in series with a Temp Controller Sensor and th R-22 solenoid. If you're Glycol has no flow, or is already cold enough, then the solenoid is closed.

    Just some random "Lesions Learned" from designing and installing (2) systems of my own.

  3. #3
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    Thanks Brian, great feedback!

  4. #4
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    Brian,

    Can you elaborate on the first-in last-out idea you mentioned? I'm trying to visualize how that works. We have a loop running to our tanks, with a valve at the end to set the supply pressure. Each drop off for a tank comes off the supply pipe, to the tank jackets, and then back into the return line.

    Also, we have lots of problems with our ASCO red hat solenoids not closing if a lot of flow is going to other tanks as well. I was guessing that the pressure differential needed to close the valve was more than was available. I'll try one of those zero differential solenoids, thanks for the tips!
    Linus Hall
    Yazoo Brewing
    Nashville, TN
    [url]www.yazoobrew.com[/url]

  5. #5
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    yeah, great feedback on glycol systems!

    my partner and i are in the final commissioning of our 3 bbl brewery in southern colorado. we are considering using braided pvc for all of our glycol "piping." i see many brewers use this for a flexible final connection to fermenters.

    is there any reason not to use it for everything? pros seem like easy assembly and far better insulating characteristics than copper. con is probably the flexibility. i think we can encase it in some additional insulation tubes and mount it to the wall directly behind the fermenters, though. we're only talking about a distance of 20' from the reservoir to the most distant fermenter.

    any thoughts would be appreciated.

  6. #6
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    Thanks!

    Thanks for the kind comments. Always glad to help!
    BTW - I made a typo in my first note. When refering to the pumps, I meant "sweet spot", not "sweat spot". The sweet spot is the point where the pump is operating at peak efficiency.


    lhall:
    If you visualize the Glycol system as a big circulatory system (or hydraulic) circuit, there is a flow to the system that travels through the Supply Main away from the process pump and chiller, through the solenoids, tanks (and Pressure Relief Valve installed parallel in the system), and returns through the Return Main. The tanks are along the Supply Main, one after the other. From the Supply Main, there are feeder lines that branch off to feed the solenoids and each tank. The Glycol goes through the jacket and exits through the "out" port of the tank, the return feeder, and into the Return Main.
    "First in, Last out" literally means that the first tank in this circulatory system is also the start of the Return Main as the Glycol exits that first tank. This tank is furthest away, Return Main system wise, from the Glycol tank. I have a sketch of this I can send along if you write me at my E-mail address. It's a .pdf file.
    If the first tank to get Glycol were the first tank to return its Glycol to the Glycol tank along the Return Main, there would be a greater amount of Glycol flow in the first tank and little at the last tank. I have seen system installations that violate this, but you need more horsepower to make up for the lack of planning. BTW, "First in, Last out" is Pro Refrigeration's recommended system configuration and they do a good job of working with you. I learned a lot from them (and the School of Hard Knocks).


    mlhardesty:
    Flex tubing is fine.........just watch our for kink areas. If you have to turn a sharp corner, use a PVC elbow with hose barbs. I've seen a lot of kinked hose in Brewery installations. When the hose gets cold, it gets more rigid, which is nice when you have a straight run. However, if it starts to kink..........it really kinks, because it is so rigid. If you can find 1.5" - 2" DIA tubing and the fittings, then the whole system can be done in that, with yoru feeder lines that branch off the mains merely being a smaller diameter of this same tubing. You'll get a snick more total dynamic head from this due to line resistance, but that shouldn't be a big issue if you size your mains right.
    Just remember to insulate everything. Otherwise you get these long sweaty tubes that drip everywhere.

  7. #7
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    any idea on what the flow resistance in pvc tubing is? (i'm a civil engineer by day).

    you didn't mention an air release valve at system high points. i have seen that recommended by others. i'm concerned that there might actually be high points inside the fermenter jackets themselves. is this an issue at all?

    thanks again,
    matt

  8. #8
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    Quote Originally Posted by mlhardesty
    any idea on what the flow resistance in pvc tubing is? (i'm a civil engineer by day).

    you didn't mention an air release valve at system high points. i have seen that recommended by others. i'm concerned that there might actually be high points inside the fermenter jackets themselves. is this an issue at all?

    thanks again,
    matt
    I was just mentioning some of the more memorable points in design. Of course, you need vents. I didn't mention quite a bit, and, as you know, it's hard to cover every base on a forum.

    PS - I'm a Manufacturing Engineer by day...........

  9. #9
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    When I built my propylene glycol system I was instructed to do like this: each unit that was to be chilled is controlled with a motorized three way valve, so when the unit do not need to be chilled the glycol go to the return piping. Before going to the main return pipe the flow is controlled by a flow control valve. The result is that you can adjust each unit so you get the right flow through each unit (fermenter, lager tank) and can balance the the whole system, regardless if the unit is chilled or if the glycol is only circulated. If using a more sofisticated temperature controller ( I have changed to a electronic for fermentation) that every second trigger the three way valve so when the temperature is close to target the valve only open/close a bit. This is good for fermentation. Before I had a cheap mecanical temperature controller which was not better than +- 2 degrees celsius. Three way valves might be more expensive than solenoid valves but they works.

  10. #10
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    That's certainly another way to do it! I find the use of the 3-way valves to be quite interesting. However, the direct by-pass to the Return Main seems to me, in my humble opinion, to be a bit inefficient.
    Why not just allow the solenoid to close and keep the pressure and flow in the Supply Main?

    Another item...........what a lot of folks don't realize is that multi-jacket FV (or SV) has a pressure differential in the jackets due to flow and fluid head that will starve the uppermost jacket. We placed PVC ball valves in the return feeders between the middle and upper jacket Glycol Out ports to allow us to tune each tank.

  11. #11
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    Brian,

    This thread seems to be attracting a lot of engineers (M.E.)!

    How do you tune a tank? Do you have a way to measure flow and temperature on each jacket? Or is it by ear

    What type of air relief valves do you use? We only have one on the bulk tank on the chiller, none on the supply lines or return lines.

    I like the idea of the three way valves, keeps the header pressure constant no matter how many tanks are flowing.
    Linus Hall
    Yazoo Brewing
    Nashville, TN
    [url]www.yazoobrew.com[/url]

  12. #12
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    "Tuning a Tank"

    Here's what we did, Linus.............

    I set up a series of "experiments" with one of our FVs that we were getting ready to plumb into the Glycol Mains. Using the clear braided tubing that we were using for the feeder lines from the Mains, we attached a water hose to the inlet feeder and allowed the oulet to run onto the floor. We didn't attach anything perminantly, and just slipped the hoses over their barbs enough to stop them from blowing off under water pressure.

    At our second Brewery, we have an inside water meter just for our location. We also have cold water ports at various locations throughout for cleaning.
    What we did was to measure the flow with a stop watch and I derived a gallons per minute value. We ran water into the (3) jackets of the FV as you would in a Glycol system and noticed some interesting results, but none that sitting down, having a beer, and thinking wouldn't have determined..........however, it was nice to see it firsthand.

    What we found was that in all configurations of in / out for the lines, the uppermost jacket is starved nearly all the time. By running the lines in from abobve, you guarentee the jackets get filled, but the uppermost has very, very little flow, if any. The cone jacket gets the lion's share of the flow, with the middle being.......well, the middle.

    We became clamping the in / out lines at various locations to observe the flow. It was one of those squeeze clamps and worked great. After picking a few locations, we found a best location that produced an even flow. I should also explain that the configuration we were testing was that the in and out feeders exit the tank from above, and the upper two jacket in / out ports have tees on them with hose barbs. Basically, the feeder comes in at a tee at the uppermost jacket, with a line to the middle jacket tee, and then a line to an elbow on the bottom port. This is pretty typical to what folks are doing up here.

    We ended up placing a PVC ball valve between the uppermost and middle jacket out ports/tees. we turned this ball valve to restrict flow out from the middle and cone jacket, and watched the flow meter with a stop watch. We derived a total water flow that was going through all jackets. We then disconnected the return hose coming out of the ball valve between the upper and middle jacket. We captured this flow in a graduated vessel and measured the time as well to get a flow for the two lower jackets (acting as one) and the upper separately. We more or less set the ball valve so that the upper jacket gets 1/3 the flow. We measured this ball valve setting and set the other FVs based on that result.

    Yeah..........sounded a little "retentive" to me as well. It didn't seem so at the time. We didn't even need a screwdriver to put our ear to to listen!

    I installed air vents (I think that's what you meant by relief, right?) at (3) locations in our lines at the high spots. These vents are basically no differnt that a submarine snorkel that allows air to rush out until liquid floats a ball and closes off the flow. When we did our first Brewery, I ordered them from McMaster-Carr, but on our second I found them at a local plumbing supply shop. Home Depot probably wouldn't stock them. They're about 2" - 3" DIA and about 4" - 5" tall with a threaded male NPT thread on the bottom.

  13. #13
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    Just a quick note: When we were disassembling our original 15 bbl brewing system (after building a new brewery and decommissioning the old one) a few years back, the PVC tubing for the glycol lines all shattered quite dramatically as we removed it. Seems that 5 years of running glycol had made it incredibly brittle.

    FWIW!

    Cheers, Tim

  14. #14
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    Hhhhhmmmmmmmmm

    Hi, Tim!

    I was wondering about the long term exposure limits of PVC with Glycol back when I was design this project. Like you, we decomissioned a Brewery to get the equipment for our new facility. They had PVC piping for much of the system, and I didn't see anything abnormal at the time of decommissioning. That Brewery was 1997 or 98.

    I did our 7 Bbl Brewery in copper, which resulted in what seemed to be hundreds of sweat joints. A real pain! I found the PVC to be real easy to install.

    Thanks for the 411 on brittleness............I'll keep an eye out over time.

  15. #15
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    I remember thinking at the time that, as (relatively) cheap and easy as PVC is to install, I'd still probably be willing to use it, factoring in replacing it every five or so years. That PVC pipe was extremely brittle, but we hadn't had any failures with it during operations.

    More food for thought!

    Cheers, Tim

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