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Thread: Boiling System (Help!)

  1. #1
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    Boiling System (Help!)

    I have gone brain dead. There is a recirculating system for boiling wort, that heats it outside of the kettle. In my mind it is called a Callandra. Does anyone know what it is really called?

  2. #2
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    I think it is called a "PERCOLATOR" Hope it helps.

  3. #3
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    Yes, it is a callandra. Basically, the Kettle is a hot wort holding tank in those applications.

    I read an article on a parallel vertical tube called an External Wort Boiler in one of the trade magazines. A cool idea, really, and showed some energy savings as well, as I recall.

  4. #4
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    External Calandria or more commonly (in my experience) External Wort Boiler (EWB). These can be full time pump circulated or part time pump with thermo siphon driving circulation during the main boil (aided by their height). Some versions that are full pump might not be oriented in the tall manner but instead be horizontal and modular.

    Briggs of Burton is big into EWB while I have seen a Ziemann unit.

    Cheers

  5. #5
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    Does anyone know what the basis is for the energy savings claim? Less heat out the stack?

    Scott

  6. #6
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    Originally posted by Sir Brewsalot
    Does anyone know what the basis is for the energy savings claim? Less heat out the stack?

    Scott

    Scott,

    It has to do with the fact your heating less volume of liquid at any given time more efficiently. Heat transfer is a function of the mass of the materials being heated...........more mass = more energy required (BTU's, in this case). Less mass = less energy.

    In a way, it works akin to a heat exchanger in cooling the wort down after a boil. In that example, you are removing heat from the hot wort and using water (or glycol-water, in 2 stage applications) as a refrigerant.
    The variables are water temperature (BTUs'), flow of the water, and flow of the hot wort.
    Heat exchange is facilitated by the number of passes and number of plates in your heat exchanger. These determine efficiency of the heat exchange.
    I'm really simplifying this example because once you have a phase change from water to steam, you go from sensible heat to latent heat, and wort cooling heat exchangers are pure sensible heat applications, but the example is still sound.

    In an external boiler heat exhange application, you remove the liquid to a different type of heat exchanger (EWB) where you can efficiently move sensible heat BTU's from steam or gas combustion into the liquid. By regulating liquid flow, steam or combustion temperature (BTU's), and the number of passes, you are basically regulating the same variables used in wort cooling, except in reverse.
    Heat exchange efficiency, in the EWB case, is is facilitated by the surface area of exposure between the heat source and the wort.

    Basically, it's a simplistic breakdown of one of the 3 Laws of Thermodynamics: Energy In = Energy Out + Energy Stored. It's all gotta go somewhere, and the winners are those systems that reduce the Energy Out the most, as this represents waste heat.

    1,000 gallons of water (wort) requires the exact same about of BTU's to heat wether you have a natural gas comustion chamber / tube, steam, or and EWB. Efficiency is measured by Energy In and Energy Stored, in this case, and Energy Out is waste heat lost in the system. This heat is generally lost in exposed heat jackets, hot combustion chamber sidewalls, hat gas exhaust stacks, etc.

    Having said all that, we can see that EWBs are analogous to the in-line hot water heaters that many of us use to charge hot liquor tanks. The energy efficiency is in the fact you are able to superheat smaller volumes of wort at any given time with more heat transfer surface area. By regulating flow you are regulating exposure time for heat transfer (BTU's / min) and determining the temperature rise per pass.

    Sorry so long winded, but I hope this helps answer your question.

    Regards,

  7. #7
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    Brewhouse manufacturers are coming up with many different ways to reduce boil times and energy. Any attempt to reduce boiling energy has to be weighed against the final wort quality/goals (i.e. sterilization, hop extract/isom., protein precipitation/enzyme denature, steam distillation). While all are important steam distillation of volatiles, in particular DMS is the most monitored and engineered for.

    Most innovations in boiling are around maximizing the wort and atmosphere surface area. First was the Calandria design with spreader. Recently Huppman has adjusted the spreader to flow streams at two different levels. Steinecker now has a double spreader…same idea. The systems have now gone beyond this to dynamic pressurized boiling systems that increase the pressure and thus the temp of wort and then reduce the pressure in a cyclic manner. When the pressure is reduced massive amounts of steam bubbles are created due to the liquid being well above boil temperature. Here you have the bonus of higher temps so faster reactions.

    Another approach is the Merlin system. Here you have a very thin stream of wort being circulated and boiled (this is really just an ingenious adaptation of a falling film heat stripper). Again you have lots of wort to atmosphere surface area so you have good distillation properties.

    I am not familiar with EWB claims for energy efficiency but I am sure Briggs would be happy to tell you all the reasons theirs is best! I can make some guesses why manufactures might claim higher efficiency’s with EWB’s. Many manufacturers talk about the number of turns per hour. This is important in that each turn means that the liquid has gone through the actual bubble stage of boiling. The EWB design (with boiler not limited by the kettle size) can give the greatest heating surface to volume ratios (excepting maybe Merlin, but that is simply a whole different animal). This could mean more turns. Also EWB can run at lower steam pressures (thus temps) and foul less. Finally, vertical EWB’s can maximize the “drop wise condensation effect” gaining greater heat transfer per unit of steam (to this point though, the condensate is cooler and will have to be heated more in the boiler).

    The other way these systems save money is increasing the number of brews before having to CIP the boiler. Look in the brewing journals and you will find reviews of many of these technologies and will get a sense of all the analysis that goes into deciding if you had a good boil. Heat out the stack is mostly a function of the heat you put in (assuming not using a condensate heat recovery system). Talk to the manufacturers for more info and if a big job you could consider hiring a consultant to recommend the best solution for your application.
    Hope this helps.

  8. #8
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    hi,

    there are some good technical articles available on the institute of brewing and distilling website (formerly the IGB). the articles are taken from the brewer international magazine and are aimed at those studying for the associate members exams. there are a couple on wort boiling, one in particular discusses different boiling systems. anyhow, they are all in pdf format and can be downloaded at:

    http://www.ibd.org.uk/igbsite/busine...inarticles.asp

    plenty of other good stuff there as well.....

    cheers,

    alex

  9. #9
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    I'm afraid I don't understand Diamond Knot's answer, so I will offer my understanding, courtesy of some bumf from Briggs.

    (a) the rate of recirculation in pumped systems in particular is vigorous and independant of the boil off rate, helping hop extraction and break formation

    (b) Depending on the design of the calandria and kettle, yu can start heating wort very early in the run off, spreading the steam load and ensuring sterility of the wort

    (c) it is not useful / essential to have kettle wall heating jackets, saving construction costs

    The main reasons people use calandrias is because of the sheer size of modern major brewhouses, the vessels are best made from stainless steel rather than copper, due to it's strength.

    But, it is a poor conductor of heat compared to copper, so the temperature differential has to be higher, and or the area of wall jackets increased. The area required by a large kettle excceds the surface are in contact with the wort - in other words, you could never boil the wort.

    The major advantage is that heat transfer is improved due to the highly turbulent wort flow, which breaks down the insulating layer of wort next to the heating surface. The high level of turbulence also keeps the calandria tubes clean as any deposits are soon scoured off (compare with CIP in mains - flow rates of 1.8 to 2.2 metres / sec being required). So less frequent cleaning is required, i.e. time and money savings.

    Typically, heating panels particularly stainless have a static layer of wort next to them, which means the steam temperature has to be higher to get the appropriate heat transfer, which then helps to bake on trub, which reduces thermal transmission rates, which means ...... and so on.

    Whether the cost wavings are worth the effort and installation expense in a micro, only you could decide

    Hope this helps
    dick

  10. #10
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    At the risk of continuing the trend here of my simple question leading to lots of very interesting, useful and very BIG answers, here goes:

    What's the smallest sized brewhouse you would expect to see a unit like this installed? 20bbl, 100bbl, more?

    Great discussion guys. Thanks.
    Scott

  11. #11
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    At the risk of continuing the trend here of my simple question leading to lots of very interesting, useful and very BIG answers
    .. no doubt. I appreciate the information, it has answered some of the questions I was researching.

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