Steam Powered Inline Water Heater and Beyond

edited January 2015 in General

This topic is a split from the Abbott's Steam Stripper thread so that we can keep the info a bit less jumbled.

As I mentioned in that thread, I am in the very early phases of building out a three tiered brew system for producing both beer and wash as well as serving as the stand for my boiler and column. It will likely be powered by electric immersion elements and an electric steam generator in the line of designs courtesy of @Telluride and @TheMechWarrior. My first implementation of the steam generator is going to be to use it to heat my water inline by running steam through side of a counter flow chiller and water through the other. I was originally thinking of using my spare stainless counter flow, but after doing some more digging online it seems like a plate chiller would work better for this application both in terms of efficiency and the inherent minor backpressure on the boiler versus the 1/2 convoluted tubing on my counterflow.

I found a diagram that seems to outline my basic idea fairly well (obviously this is nothing original), and would love suggestions on how to improve such a system, and do you think the steam will provide enough heat to achieve a significant rise in water temperature at a flow rate of say 1 gpm with the proper exchanger? I would also love some assistance with the in depth steam calcs ala @TheMechWarrior in terms of sizing out an appropriate plate exchanger(s) rather than my usual method of buying a few and sticking with what works ;)

All in all, I just wanted to get a new, separate discussion started regarding alternative uses of steam, and will hopefully get to work on the boiler build in the coming weeks.

image

Comments

  • edited January 2015

    I should also probably note that that diagram is courtesy of Spirax Sarco and they have an enormous wealth of steam information which can be found here if anyone else is interested

  • N°1 rule...design first and build second.

    It's late here (for me) so I'll leave it at that for now. Thanks for the new thread, I'll see what I can add after sun-up to help you along your way.

    Cheers,

    Mech.

  • edited January 2015

    What does all this added complexity buy you over a standard electric rims or herms setup? By using electric to make steam, and then using steam for the heat exchanger, you are going to end up with a setup that is significantly less efficient and significantly more expensive. Not only that, but you need to deal with the complexity trapping and managing condensate.

    We've got a huge Basco 5"x48" stainless u-tube heat exchanger that is planned to be used for a similar purpose, steam heating water, likely recirculating. Efficiency not so much a concern for us with a 15hp steam boiler, we need all the other associated steam trim anyway, so adding the exchanger is trivial.

    The image you posted uses controlled pilot valves, for steam trim many of these are pneumatic, the running gear for this tends to be very expensive.

  • I have seen more than one small brewery use a propane instant hot water heater mounted on a grocery cart with the propane tank under the cart, and they plug it in and connect it to a faucet... wheel it over to the brew system, turn it on, open the faucet, 170 degree water flows out...

  • edited January 2015

    If you already have an inline steam generator then you also have an inline water heater. All you need to do is adjust the water flow rate so that it produces hot water instead of steam.

    Size the steam generator so it can fulfill your requirements as a water heater and it will probably be big enough to satisfy your steam requirements also.

  • but if you are not using RO/DI water in your steam generator, say you are just heating water in it to 170, you are asking for build-up to happe, aren't you? also, the steam generator with a single element is nowhere near the power and water flow of an off-the-shelf 200k BTU unit, right?

  • edited January 2015

    You'd easily need 50kw of electric to match a 200kbtu fuel fired on demand heater, 10 elements. Cost of the on-demand is going to be much lower as well.

  • Restaurants use inline on demand hot water heaters and a booster to get above 180F. The boosters spec 70F above temp in at 150 gpm. www2.hatcocorp.com

    These units also use tap water, so no idea about sediment buildup.

    I imagine one of these boosters in a closed loop. Water from the bain marie returning to be reheated.

    DAD... not yours.. ah, hell... I don't know...

  • edited January 2015

    You can recirc with a tankless, just make sure you've got it plumbed right and don't run it dry. With a commercial controller you can get it to 180s.

  • I've spoken to a few distillers with custom made instant hot water systems and the consensus is don't bother. There's off-the-shelf units that are cheaper and easier to maintain.

    With respect to sizing calcs for plate heat exchangers I normally deal direct with Alfa-Laval, here's a link to their main site:

    Plate heat exchangers

    A sales rep will talk you through your process requirements and send you through a quote for a unit designed specifically for your needs. PHE are not that expensive.

    To know what form of heat exchanger is best you'll need to supply:

    • Volume to be processed
    • Cooling/Heating time required
    • Inlet and outlet temperature requirements (product side and cooling/heating side)
    • Physical properties of the products on each side of the plate such as solids concentration, viscosity etc an experienced sales person will have a fair idea of what your product is etc

    There's a very good reason I mention time, if your process loading is intermittent you can utilise a "thermal bank" or chilled water/hot well buffer tank to compensate for a much smaller unit operation. The benefit here other than reduced capital costs is that you can now run your power hungry equipment during off-peak times and store the bulk of your heating/cooling needs in your buffer tank. These are very specific financial decisions driven by your specific energy pricing schedule.

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