Using water from boiler to jacket instead of steam?

[Butcher Scott]

Folks,

We tying our boiler into our 15bbl Pub built kettle, and our boilermaker came up with the idea of using our 15hp steam boiler to output 15 psi water at 250 degrees isntead of steam.

The boiler company has provided us approval to use their boiler for this use, 15 psi is plenty to get water to 250 degrees and there are a lot of costs savings by going to this method: reduces the number of costly boiler inspections, won't need to constantly chemical treat the steam, 100% of the water will be recycled in this closed loop system so we'll have less water usage, and water (we'll just fill the thing up with distilled water) will be more efficient at transfering heat due to increased surface temp.

My question is - has anyone else done this? The immediate concern is whether the jackets could handle the increased weight of the water inside of the jackets. It's 3/4" stainless coils on the inside of this thing, so I would think the increased weight (which would only be a couple of gallons max anyway) would not put too much strain on the jackets.

Has anyone else done this? Any opinions on this crazy scheme?

[HubCity]

tagging this thread as I am curious about this as well.

[BeerBoy]

Not quite apples to apples but from a prior thread:
http://www.probrewer.com/vbulletin/s...ead.php?t=9255
I guess it comes down to the question of wouldn't you see more breweries using this if it were more efficient/cost effective? It's just not out there. If you do go down the super-hot water path, do let us know the results. Who knows, maybe this could be an answer/alternative approach.

[gabewilson50]

. . .and water (we'll just fill the thing up with distilled water) will be more efficient at transfering heat due to increased surface temp.

Unfortunately, your jackets are designed for steam (I assume) and not for water. The amount of heat you can extract from superheated liquid is nowhere near what you can extract from the condensation of steam. Assuming you can extract ALL of the heat (from 250F to 32F) from your water (which you can not, because you'll only get as low as the temperature of the liquid you're trying to heat up in a 100% efficient exchanger), you only get approx. 505 kJ/kg of heat. With a steam system of the same pressure, you're extracting the heat of vaporization of the steam (which you are getting about 100% of this energy because you don't return steam back in your condensate lines) which equates to over 2200 kJ/kg of heat. That's over 4 times the heat extraction of the 100% efficient (and impossible) superheated water system. I guess what I'm trying to warn is that if you do this, it could take all day to heat to a boil in the kettle. I'd have to say it's a very bad idea, unless someone can prove to me otherwise.

--Gabe

[gitchegumee]

I totally agree with the above post. And would further take issue with some of the other "benefits" you've listed. You will still have to treat water with chemicals. Distilled water is extremely corrosive. What's going on with heating the water doesn't much matter whether you make steam or hot water. And a well designed steam system is a closed-loop system. All the water that is vaporized get condensed and sent back. No gain here. And the temperature difference doesn't exist. If you can make 15 psi/250F water, then you can make steam at the same temperature--only LOTS more powerful due to phase change. Your boiler guy doesn't seem to realize the power of steam is not in the temperature, but in the phase change from gas to liquid at the same temperature. Furthermore, with steam you "pump" the steam from the boiler to your jackets with the boiler pressure. A relatively small condensate pump then pumps the condensed liquid back to the boiler. With water, you'll need a much larger/more expensive/energy intensive pump to pump lots more water. The least of your worries is the weight of water in the jackets. These jackets are usually conservatively designed stainless. Go with steam the way everybody else does. There's no secret way to gain benefit with liquid water. Good luck with your install & hope you're brewing soon!

[South County]

Yeah what he Said^^^^^^. Also keep in mind that most off the electric in the US is generated by steam turbines. Obviously not the exact same application but true evidence in the power of steam in its ability to transfer energy. I would think that if there was a more efficient use of BTU's it would have been done by now in the beer industry.

[dick murton]

I worked at one major brewery which used high temperature hot water - 170 psi and 170 deg C if I remember correctly. Nasty stuff it was too if you had a leak, though I realise you are not considering these conditions.

I also agree with the previous comments - stick to steam, it is simpler. I haven't got my temperature / pressure charts to hand, but I think the pressure you need will not be much different for steam - so no real gain. And the water is incompressible, so safety devices have to be even more robust

And collect the condensate and recycle it if the system is not kitchen top size - save on water treatment and energy