Heat Exchanger vs. Tankless vs HLT

[JeremyG]

we're currently using a Heat Exchanger for our washdown hose that's directly hooked up to our boiler which got me thinking why we couldn't do this in lieu of a Hot Liquor Tank. Is there a downside I'm not seeing? Is it a better idea to just go with a tankless Hot water heater?

I'm asking because I'm about to trash my HLT as it's leaking pretty badly. I think we're just going to convert our CLT to our HLT and to prevent the cracking we were going to install a heat exchanger to pre-heat when refilling, which of course just got me thinking why bother with the middle man/tank.

Any thoughts would be appreciated.

[ArmstrongBrew]

Heat Exchanger

So, with a tankless, you are heating with combustible gases in a heat exchanger manifold. My thought is that steam would be MUCH more efficient depending on the quality of the steam. The specific enthalpy of steam is much higher than gas and I would think your efficiency would be better.

I still wouldn't get away from the HLT idea though. You still have the ability to adjust your temp in the HLT once it comes out of the heat exchanger. Also, capturing your cooling water for cleaning is a big benefit

[jfulton]

On large HLTs it is common to use a HE in place of tank jackets, as heating is just too sluggish in big tanks (above ~60BBL), and is uneven. You will need to install a recirculation pump to be able to raise the temperature on a cooled tank, this also has the benefit of homogenizing the temperature.

[Natrat]

You can make your own tankless using steam and a HX if you like...you need lots of excess steam capacity, and a big ass HX. Plate doesn't flow as well as a tube and shell style.

Works well, in my experience. But it's hard to control the heat, I find.

Good luck

Nat

[jfulton]

The HE does not have to be that big when you install a recirc/process pump to heat the tank. To control the temp, the pump just stays on while you're heating the tank and a solenoid/pneumatic valve controls the steam flow until you reach your SP. Need ~5lbs steam/hour per BBL.

[Natrat]

The best reason to have an HLT is so that you have a reservoir of hot water. If you only use hot water for your mash, you can get away with some other system. If you like to have hot water for cleaning your floors, CIP, mixing soluble ingredients, thawing out frozen stuff, putting painful blisters on your leg, and other fun stuff, a hot liquor tank is the way to go. Generally at least 150% of your brew day, but it varies by personal preference.

And if you have no space, you can get a big ass HX about the size of a home hot water tank that will give you all that process water pretty much immediately without a towering HLT. Personally, I like having an extra tank to clean

[jfulton]

I totally agree with natrat, and realize I missed the point of this thread. I was thinking you were wanting to use the HE to heat water into some other tank that would then feed your processes. It's much less handy using a HE without a reservoir of some sort to draw from.

[JeremyG]

So the opinion here is that if I'm going to use a HE in this situation, I'm better off using it not just to fill the HLT, but to keep it at temperature as well, rather than using the jackets to do so? My original thought was just to bring the temp of the water up to 160 or so when filling the tank and then keeping it at temperature with the jackets, but you'd recommend bypassing the steamjackets and just using a recirc pump? Is this more steam efficient or less? my HLT is only 40bbl's FYI.

[jfulton]

The HE is faster and more efficient, though you use energy pumping the water through. However, you would need to recirc the tank anyways to get a good temp reading. I would vote for one or the other with that volume, both would be redundant. Sure you can get it to temp faster with the HE, but you spend unnecessary money if the tank already has steam jackets.

[JeremyG]

well, I already lost, or am losing, a HLT because when I fill it with ambient water the change in temperatures seems to have harmed the integrity of the tank causing cracking and leaks. I was hoping by using the HE it would prevent that.

[Matt Dog]

Do you carbon filter you HLT water? Chlorine will ruin HLT's. Going from a 40 Bbl HLT to any type of on demand system would be rough. Seems like it would be tough to get a consistent temp and flow for mashing in.We have a couple Rennais for supplementing our HLT and they just keep up with a sparge on a 15 Bbl brew. They also suck for cleaning tanks because of low volume. The HX idea seems much better if you have a boiler.

[Fullcourt]

I have been reading from so many sources of information that I cannot remember where I saw this theory, but here it is.
If there is moisture inside your cladding, then the chlorine in the insulation can leach out and start attacking your SS jackets and your SS tank walls, which then leads to more leaking and more degradation, cracking, and deterioration.
If I can remember where I saw this, I will post it.

[gungadin]

Wet insulation

I'm pretty sure the discussion of improper insulation damaging tanks inside the cladding is in the probrewer used tanks info area.

[Fullcourt]

I'm pretty sure the discussion of improper insulation damaging tanks inside the cladding is in the probrewer used tanks info area.

yes, thank you, under: Stress Corrosion Cracking

[Diggity Dave]

Stress Corrosion Cracking

Sounds like you are dealing with stress corrosion cracking. Here's a post from another thread:

http://www.probrewer.com/vbulletin/showthread.php?t=9943&highlight=stress+corrosion