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Heat exchanger sizing, operation and control

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  • Heat exchanger sizing, operation and control

    as a 3bbl nano, there is almost nothing between the little homebrew sized jobs and a big ass unit from thermaline/CPE/alfa/etc. very large difference in pricing. i've built some quotes on CPE and thermaline for HX that come in around the $1500 mark for carbon steel frames. CPE has the 30xxx models, which state 6 to 20sf, which i assume cover the span from 1 to 5bbl, as that's the volume selection you can make. the duda diesel is a hell of a lot cheaper, and has area of 1.9m2 which is also 20sf. does that sound like enough surface area for 2.5 to 3bbl batch-- 20sf?

    as to operation of the exchanger, i guess i never paid attention like i should have but i was recently reading some literature when looking for the new HX. i'm not sure i understood it correctly but the summary was saying that higher flow rates will increase the cooling efficiency, which seems a bit counterintuative to me. i thought the longer the wort stayed in the plates the more heat it would give off to the cooling fluid. are we talking about the difference in flow rates of hot vs cold? or just total flow rates for both? am i reading that right or am i way off....?

    i just always remember my old brewmaster talking about throttling down the flow to get the knockout temp right. i assumed he meant slow the wort, shoulda paid more attention ....

  • #2
    There talking about the flow rate of the cooling side, tap water or glycol!! The high the flow rate of input cooling water or glycol the better or high the cooling rate for the hot wort!!!

    One thing you do need to consider is the temperature of your input water, tap water , during the summer, warmer tap water, greatly reduces cooling, BTU.

    There also a couple other places you might look at for Heat Exchanges, try GW Kent, or Glacier Tanks, both have SS Cleanable Heat Exchangers.

    Check the temperature of your tap water, check it after its been running a while!!!

    Gregg Culhane


    • #3
      Thats what I thought. City water is at a set flow rate so we would throttle the wort back to help pull some more heat out.

      unfortunately our cooling water doesnt get very low. Maybe 60-65 in the winter. Summer could be 75-80 or so. So ive been looking at upsizing the unit a bit. Ill check out glacier and gw. Hadn't thought to look there.


      • #4
        Winter tap water temperature of 60 to 65 is ok , not great, but your summer temp is going to be a problem, you have to address that in a different way, your going to need to have a 2 Stage, Heat Exchanger, One for Tap Water & Wort and then One extra for Cold Water or Glycol & Water mix, via a CLT, or Big Gycol Chiller.

        So the easiest and cheapest way is a CLT that you use in the summer, you fill it the day before you brew, chill it to around 40 deg, and by the next day 24 +/- hrs later, should be good to go.

        Size / bbl, depends on your brew size, tap water temp., Heat exchanger size and wort cool down time need, like 30 min. or 45 min. or 60 min.

        Check with a Heat Exchanger MFG. Like Thermaline, there good. There are others too..

        You can call me if you need to 209-467-3300 Pst.


        • #5
          As a 2 bbl nano, the Sabco Plate-Pro Sanitary Wort Chiller works extremely well for us. At $749 it was the answer to our cooling problem.


          • #6
            I wouldn't recommend a duda chiller, or any non brewing HX for that matter. Their cooling passages are smaller and clog easier.


            • #7
              Make sure you get a HX that is made for sanitary conditions, and one you can take apart to inspect.

              Make sure that you have the flows plumbed correctly. It should be in a counterflow configuration - cold water enters on the side where chilled wort is leaving.

              You will never get your wort chilled to more than 2-3 degrees above the water temperature no matter how big the HX, how fast the flow of water is, or how slow the flow of wort is.

              There are calculators on the web that you can use to size a heat exchanger. You give the flowrates and temperatures of the liquids, and it will tell you how many sq feet of cooling surface you need. I think there is one on Mueller's website.
              Linus Hall
              Yazoo Brewing
              Nashville, TN


              • #8
                i appreciate all the advice. yes, we are aware of cross-plumbing the flows i.e. "counter flow"; aware of the limitations of cooling water that is at or above room temp, and already familiar with a two stage cooling, although in a non-traditional mode.

                i actually went ahead and ordered a larger unit from duda- its a little over 20sf of area, and it has sanitary fittings, although they are the small 1/2-3/4" TCs which are a bit of a pain. the gaskets are tiny and easy to lose. but alot of our hoses off our kettle fittings are only 1/2 so not a big deal, and yes, it is in fact sanitary.

                the clogging is a bit of an issue, but our kettle has a bottom port and electric elements, so no matter how hard we try we never really get a super tight cone. we bought a S/S TC strainer/filter and that was the end of that problem. havent bothered packing it with leaf yet but nice to have the option.

                so for us the only drawback is that you cant disassemble. so we'd clean the hell out of the old one. never gave us issues, knock on wood. we use PBW/cellRmaster for cleaning, and a little dash of some naoh as a booster to give the HX a super clean. acid, then sanitize with 180 fresh water and we've never had an issue so far.

                i had seen the sabco unit a long time ago and completely forgotten about it. i'm a little torn as it is sanitary, breaks down for cleaning, etc but given the fact that our duda unit is still sanitary and over twice the cooling area at less than half the price i cant say i wouldnt have made the same choice. dollars are still expensive in mexico.

                we'll run water in the new big one, and then connect the older smaller one in series with glycol for two stage. should get us where we need to be once i dial it in after a few brews.


                • #9
                  and while we're at it, anybody care to check my math?

                  our place is a brewpub, and the restaurant has a 1000gal underground tank for water since the city service can be spotty in mexico. on our first batch i use clean (tanker truck) water first for cooling so i can fill our two 100gal tanks with hot water for our next brew. then i switch to the city water. but mexico's drought is as bad or worse than CA, so i'm thinking of connecting to underground tank and basically just recirc in a loop to save water.

                  1000gals is ~8300lbs. we typically have about 75ish gals of wort (620lbs), and since we WP most of our beers, it goes to knockout around 160ish, but let's say 170. if i get 100 degree drop on 75 gals, thats' 620lbs x 100 dgr or 62,000btu.

                  so in a 1000 gal/8300lb reservoir that's 62000/8300 or 7.5F rise in temp in the reservoir. yes? maybe a little less as the earth will absorb a bit of heat as the reservoir warms.

                  so if the reservoir is at a stable 60 or 65, at most i'd bump it to 72-73F. if i'm right, it sounds like having the small 2nd stage for glycol should easily put us into the low/mid 60s.


                  • #10

                    so- we went with the big ass duda chiller. it chills like a bad ass, however, we had issues with flow. there was a pretty large pressure drop, so the wort was crawling out on the second batch. not surprising it was cold. two issues- we use an inline strainer and it was pretty clogged with pellet debris. and also i think it has alot to do with the fact that there arent alot of good pump choices for a nano. not any extra pressure we can add without going to a much bigger pump. the second batch of the day took forever. like 2 hours or something crazy.

                    so swapping out the duda for the sabco model on the advice of mr Fatback here. going to use our 1/2hp pump and just throttle it back with ball valve after the HX.

                    lesson learned- do NOT ignore pressure drop if you have a little nano pump. especially not if you're double batching.


                    • #11
                      I am using the Sabco and no filter whatsoever. I run a whirlpool during the boil and continue for 5 minutes after. I let settle for 15 minutes then pump out to the sabco heat exchanger. Never had anything clog. The filter may be causing the biggest backup in your scenario.


                      • #12
                        True. And we are changing up our process to give a long rest after WP to see if we can drop the filter. But at tthe end of the day, even before we got the strainer the second batch was crawling along. Great for cool wort, not great for wrapping up a long brew day.

                        I did actually find a sanitary pump online that is 3phase and triclamp and similar in cost to other nano pumps. But its from china, so going to search for reviews or folks who have tried them. At up to 1hp and 3ph itd be perfect solution- sanitary, small but still vfd capable. Between that and the sabco we might finally get everything running smoothly.


                        • #13
                          What pumps are you guys currently using? I am setting up a small 2BBL system and have ordered a Chugger MAXX for the kettle to pump through a filter, chiller and the 20m transfer line then back to the kettle for sanitising so theres a bit of pressure drop there.
                          I am also trying to work out what chiller to use, was going to go 2 x brazed units but now thinking small gasketed type. Other than Sabco what are the options? I had an Alfa Laval one quoted at $4k


                          • #14
                            we had a topsflo. small brushless, similar to chugger, etc. but just didnt have the power to push through our setup and into 2nd batch of 5bbls. it just couldnt cut it. way too slow.

                            we have been using a jet05 from st pats of texas. sanitary 1inch centrifugal, but only 1 phase so cant use a vfd. we've had to throttle with a valve which isnt ideal. i'm looking at a few chinese pumps, especially one that is 1hp 3phase, washdown and 1inch triclamp. very cheap. just been waiting to pull the trigger as we have a few other pieces to sort out before we get to that. send me a pm and ill give you the info if youd like.

                            we went with the sabco chiller and it seems to work well enough. i think the duda we had chilled a bit better, but had a bit of pressure drop that the little pumps couldnt overcome. seems to work fine.