Electric Boilers

[Tash]

Any advice out there on Electric boilers? Simply not enough room for a gas fired boiler. It requires 450,000btu/h should the boiler be 'oversized' to accomodate a jacketed mash tun, kettle and HLT all running at once?

Just looking for any thoughts in regards to lack of steam, breakdowns and maintenance.

Thanks!

Tash

[tarmadilo]

I don't have any experience with an electric boiler, but I have brewed in situations where there wasn't room for a gas boiler, instead we used direct fire on the kettle. Just an option!

Cheers, Tim

[MickDuffs]

You can put a boiler just about anywhere. We ended up putting ours in the basement and running a couple hundred feet of pipe to our brewhouse. Talk to a boiler installer they should be able to go over your options. They should also be able to size a boiler for you.
Duffy Mahoney

MickDuff’s Inc.

duffy@mickduffs.com

312 N. First Ave.

Sandpoint, ID 83864

Phone: 208-255-4351

Fax: 877-233-1705

Cell: 208-946-0844

[Larry Horwitz]

yep....and avoid electric at all costs...or you will pay for it forever and ever, and ever..

[RobZamites]

Well, technically, you'd "pay" for a gas boiler "forever and ever" too. My Sussman came packaged with the brewhouse I purchased -- a brought in a great boiler guy who marveled at how the last owners might have made it work, and consequently is plumbing up a system that will actually do the job just fine. I think if you take good care of your equipment, have it installed properly and learn how to use it properly, there's no reason it shouldn't serve your purposes just fine -- be it direct-fired brewhouse, steam brewhouse, or an electric OR gas fired steam boiler system

Just my two cents' worth. Flames to /dev/null.

[Larry Horwitz]

Yeah, but you'll pay as much as 2x more for the steam it generates (depending on the market) and you'll have to replace the element(s) way more often than you'd have to replace gas burners.

Find someone you know who has an electric kettle or steam boiler and ask 'em....you'd be hard pressed to find supporters.

[kugeman]

Kind of along these same lines, I have a 7bbl direct fired kettle and 10 bbl electric hot liquor tank. I love the direct fired kettle, it gets a great rolling boil very quickly. BUT the electric hot liquor tank is a piece of junk (it's not poorly made, it's just not that effective). It costs about $600 to replace the heating element when it burns out (which has happened twice in 8 years) and it takes two days to raise the temperature of our water from 48 degrees F to 190 degrees F. It also uses a ton of electricity (luckily we have municipal electric here so it's not too expensive. But in most locales it would be very expensive).

I would never get an electric hot water heater again. Although I can't speak for the effectiveness of an electric steam boiler.

Just thought I'd throw it out there...

[RobZamites]

Larry,
I can't speak from experience (this is my first electric boiler), but I see no reason why, without proper maintenance and use, it should be any less reliable and have a shorter MTBF than gas. How many people do you know that replace the electric elements in their stove?
Electric boiler users, please chime in with your horror stories....

[Larry Horwitz]

you won't hear many....'cause very few people own them. Just doesn't make fiscal sense. too much $$$

[RobZamites]

Well, it's what I have to work with, fortunately, those little Sussmans only hold about 15 gallons of water and this particular one is only a year and a half old. We did manage to save quite a bit of logistic nightmares on install vs. a gas plumbed boiler however -- the general contractor was loathing the idea of having to core another hole through the concrete/steel pan of the brewhouse floor!


Rob

[uptown brothers]

anybody recalculated operating costs, electric vs fuel oil or propane (assuming one has no access to natural gas from one's local utility)? I'm understanding that at current propane and fuel oil prices, electric is a better deal IF, where you are, electricity costs less than 20 cents per KWH. Emphasis on the "CURRENT propane and fuel oil prices"......

just thinking electric isn't as slam dunk a loser in this decision-making process that it used to be.

[Diamond Knot]

Back to the original question........

Actually, before you could determine if the boiler you have will work for all those applications, one would need to know what volume your system is. However, one can sort of mathematically mock up what would be required for 1 Barrel of water and you could multiply that by the number of barrels you have in each vessel. You also need to know the amount of time you are willing to wait for this heat transfer to take place.

There are numerous considerations when calculating heat transfer and energy needed for heating water systems, but very simplistically put:

C*M*dT = BTUs

Where:
C = Water coefficient fo heat in BTU/lb-F. For water this is 1 BTU/Lb-F.
M = Mass of water in Lb.
dT = Delta temperature, or the change in temperature, in Farenheit.

Example:
To raise 1 Bbl of water from 65F to 212F (just below boiling, but NOT boiling) in 1 hour, it would look something like:

(1 BTU/Lb-F)(8.33Lb/gal x 31 gal)(212F - 65F) = 37,595.8 BTUs total

If you wanted to heat this water instantaniously in some Star Trek-like fashion (with Scotty's trusty ol' matter-antimatter, plasma injected, positronic relay controlled HLT, no doubt), it would require this amount. If you wanted to do it in an hour, it still requires the same energy, and if you wanted to do it in 1 day, it's still the same.

If your boiler produces 450K BTU/hr, then by:

(450,000 BTU/hr) / (37,595.8 BTU/Bbl) = 11.97 Bbl/hr

So, about 12 Bbl can be heated by a 450K BTU/hr boiler in 1 hour.

However, holding that temperature is a lower energy deal. Once the volume of water is heated, you are merely dealing with heat transfer losses through the insualtion and tank walls. Say your HLT was poorly insulated and dropped 5F/hr, then your boiler would only need to make up:

(1 BTU/Lb-F)(8.33 Lb/gal x 31 gal x 12 Bbl)(-5F) = -15,493.8 BTU

So, by this simplistic example, you can see that though it takes 450K BTU/hr to heat 12 Bbls of water in 1 hour, it only takes 15.5K BTUs to hold it there once you do.

And that, folks, is why you should always try to scavenge your heat exchange water, too.

Now.............for boiling.............
The rules change here a bit and since we have already achieved 212F, a change in temperature is no longer a factor. The water is passing through a phase change from liquid to steam:

Lh * M = BTUs

Where:
Lh = Latent heat coefficient. For steam this is 970 BTU/Lb.
M = Mass in Lb

In a 15 Bbl boil at our B2 site, we lose around .75 Bbl to steam in 1 hour, so I would equate that to 5% vaporized. With that reckoning, for every 1 Bbl of water we lose about 1.55 gallons to steam vaporization and evaporation.

(970 BTU/Lb)(8.33 Lb/gal x 1.55 gal) = 12,524.2 BTU

If you notice from above this is almost what it took to just hold 12 Bbls at temperature! Also, only that part of the boil flashed to steam is counted in this calculation. The rest of the energy is merely maintaining a 212F temperature and overcoming heat loss. Boiling water and flashing to steam is a high energy proposition and I have seen where a heating method (both in steam and direct fire systems) has enough moxy to get the kettle hot but not enough "oomph" to create a decent boil..........it just sort of languishes there. Pitiful sight.

I know...........all this is a major bore. However, if you're going to run a Brewery, you have to be part plant manager. There's more too it than "Do I have enough to heat this and that and that?". At B2, we have a Parker 625K BTU/hr 15 hp boiler, can heat our 15 Bbl kettle under boil and maintain a 1,200 gal HLT or we can heat the 1,200 gal HLT and a 600 gal HLT.

On the matter of energy source, I must throw in with the natural gas side of the house since I've actually done this calculation before for an electric 7 Bbl brew kettle. Electricity is beacoup expensive up here in the Northwest, and it took about an hour of research, calculations, and a bottle of suds to determine we weren't going that direction.

I hope all this helps in your selection process!

[gitchegumee]

Three things I must chime in on here. First, thanks to Diamond Knot for the calculations. There is another factor when considering pricing however: gas burners also send a ton of heat up the flue. Most folks are lucky to get something close to 80% efficiency (and usually much less). On the other hand, immersion electrical heating is 100% efficient--all the power going in, stays in. Don't forget efficiencies in the comparisons.
Second, Kugeman, where are you buying your elements? Seem pricey and underperforming. I can get 10hl of 82C hot liquor overnight with a 10kW element that I bought from McMaster for less than $350 (P/N 3656K93). And electric is safe, easy and automatic. Burning out elements sounds like running them dry. You should always have a float switch in the tank to turn off the element when the water level drops to (maybe around) 10cm from the top of the element. And many elements have a thermoswitch to turn the element off in case the local element temperature rises to over (maybe around) 110C. IMHO, electric HLT is the only way to go for 10BBL & under.
Third, Tash, unless you are brewing back-to-back batches, there is no need to use your mash tun, kettle and HLT all at the same time. You should not have everything running at once. Size your boiler for the kettle, and you will be fine. With a decent heat exchanger, you can even mash in while knocking out without kicking on the heat in the mash tun. Good luck!

[Diamond Knot]

Awesome

Great chime in, Phil!

Ahhhhh........McMaster Carr..........were Diamond Knot loves to shop! I can't iterate enough to any brewer out there that has to maintain equipment the need for an M-C account. I recently built our semi-automated keg washer with a scullery sink, scrap stainless, and all components from M-C. Great folks, too.

Yes, there were a lot of considerations missing on my long rambling post on heat transfer. Efficiency due to heat source is a real factor, and immersion is indeed more efficient than say, a simple flame blasted at the lower surface of a brew kettle, HLT, or similar.

In addition to your great message there, Phil, I would add that we at DK have seldom, if ever, had to steam a mash. We've had a coupel of occassions when we were step mashing for a lager and just couldn't quite hit the temperature initial numbers, but that's been twice in many years. If you're making Ales, and even Lagers with good planning, you shouldn't need to heat the mash tun. Just my observation and $.02.

Regards,

[Butcher Scott]

Thanks Brian for the great calculations!

One other thing that I think needs to be considered about the electric boilers is the amperage required to run the boiler.

Gas is (still) cheap in my neck of the woods, but I very briefly looked at an electric boiler. Our MEP engineer came back and informed me that the 400 amps that would be required to operate a 15 bhp electric boiler would double the amperage requirements for our entire pub!