I wanted to re-create a thread based on some difficulty I had with this very topic. I read quite a few threads with respect to the use of heat exchangers or plate chillers in home brewing, and it seemed like there were a lot of gaps in some of the information.
This isn’t designed to be a debate on the efficiency of heat exchangers vs counter flow chillers vs immersion chillers. It’s just what I found out from some very helpful friends and some people at Duda Diesel (this is not an advertisement either).
If you have something to add to this, or a correction in something I have miss-understood from them, by all means let me know by reply so I can edit the thread. I have simply put in here what I, and my colleagues have experienced as the average scenario of use.
• You want to chill as quickly as possible, but in reality it doesn’t need to be instantly. Commercially they are chilling huge amounts of wort and it may take an hour or more until the last drop is cooled down. In home brewing if you can chill your whole batch down in 10-15 minutes, that’s plenty fast. Some argue 20 minutes is acceptable. Try it yourself. Actual application on your own system vs armchair master-brewer theory are completely different ball games.
• More plates are not necessarily better. You’re looking for longer contact between the cold water and the hot wort so that they can equalize. A longer plate chiller is far superior to a shorter plate chiller in many ways. You’ll find that a 50 plate short heat exchanger will actually take almost twice as long as a 30 plate long one. It’s important to size correctly for your application and batch size. In an infinitely long
plate chiller, the two fluid temperatures would match exactly, so we need to find a nice medium. Shorter and more plates allows for a higher PSI to be used. Longer allow for more efficency with lower PSI (like that of your garden hose).
• Water flow is the most important part of these heat exchangers. The more flow you have, the faster you can run your hot wort through to cool. The calculations done for most home brewer exchangers are based on a 5gal/min throughput. This is what you'll find as a flow rate on your exterior taps at your house. For my heat exchanger, it allows a flow rate of 2gal/min to exit at 70*F. If I were to use a pump and had a system that would support 10gal/min, I could then double the throughput of the wort. This is really a non issue because you can cool a 10gal batch in about 5 minutes on a $130 heat exchanger. Remember, your flow rate is not always 5gal, and in many cases its actually much lower. Throw a thermometer on the output of your heat exchanger and make the necessary adjustments of your pump output valve to limit the flow of your wort to achieve optimal pitch temp. If you're gravity fed, you can limit the output from the boil kettle valve.
• If you want to size, Duda Diesel has a chart you can measure your system out on to get the best possible result. Their charts assume a wort inlet temp of 212F, water inlet of 68F and a wort outlet 75F. They recommend a B3-23A as their high performance unit for home brewers. The 60 plate long version makes little performance gains (1 min saving) unless you're able to max out the water flow portion of the unit. For a home brewer, this would mean using your HLT as a water buffer and having a dedicated pump to flow more through the heat exchanger. Personally, not worth the hassle or the money.
• I want to minimize the amount of dicking around I do with my process so I sized so that I can go straight into the fermenter. I want to make my process as easy as possible, not more difficult. Some will aruge they like to re-circulate the wort back into the boil kettle, but I find this to be a pain in the ass and it takes too long. I sized my heat exchanger for pitchable output temp in one go and WP the boil kettle. Your mileage may varry.
• There are some things to do with hops and DMS and such with chilling times, but its more than I want to type here.
• A whirlpool will work just fine for these. Use a side pickup and skip the filter if you don’t have one. The units don’t clog up as easily as people suggest they might. You dont need to worry about your wort sitting around for an extra 5 minutes doing a hot whirlpool. (SankePankey
reports problems with this so take this tip with a grain of salt)
• Heat exchangers are quite easy to clean with PBW. Percarbonate based cleaners are just fine for cleaning of copper and stainless steel. Do not use chlorine or bleach to clean your 300 series stainless steel equipment! Just re-circulate pbw cleaner through your heat exchanger (I do my whole system at once) for 30 minutes. Make sure to sanitize with boiling water or star-san prior to use. Some suggest you can bake these in an oven at 300 for an hour or two if it makes you feel more comfortable but I find a re-circ of my system works fine (and infact helps my March 809 pumps from getting sugar buildup). You may want to try sodium hydroxide to really clean out any gunk that might build up inside once in a while, but I'd suggest you read your ass off before using it. Consider yourself warned.
• Remember, a beer brewed on your system will be entirely different than a beer brewed on another system. This is not necessarily better or worse, it’s just different because of the setup of your equipment and the process you take. Just because my 30 plate long filter works for me, it does not mean a 40 plate short will not work for your process. I point this out because there are people out there that will claim “the way” and in reality, not even commercial systems are 100% every time.
• Find "you way" to make exceptional beer, be it kegs, pumps, blichmann pots or coolers. There is no "right way" no mater what people tell you. The journey to being a great home brewer is half the fun.
Good luck to everyone! I hope this helps someone else in their questions about heat exchangers.
Performance chart is linked below for sizing of heat exchangers. I do not know how they apply to other manufacturers as they are known to have different flow paths and efficiency.
Thanks to Duncan in Calgary and Bryan at DudaDiesel for the great help.