providing domestic hot water with mult boilers

Ron Schroeder_2

Hi Mark,

Are the boilers also going to be used for space heat?

My first though would be primary/secondary piping for the boiler water and reverse return piping of the DHW side of several indirects.

I would suspect that the indirects would be longer lasting.

Ron

mgs

indirect water heaters in commercial applications

I'm in the process of specing a project that requires a 1000 gph of domestic hot water. The contractor is wanting to do this with multiple boilers, indirect water heater and storage tank. First of all does it seem practical to do this with boilers versus the high effiecency commercial water heaters? And what do you think we can expect on the life span of the indirect?

Any input would be appreciated!!

Weezbo

here is an idea....Jumbo.........Take a look at Triangle Tube

.The Jumbo is one kinda bad boy

Constantin

I would consider a condensing boiler...

...like two Munchkin VWH. For example, one Munchkin VWH 399 will raise 650+ Gallons of water 70°F per hour. Combine that with a 199 model and you'll have the capacity for 984 gallons/h of 120°F water all day long. Or upsize to two 399 models in case your temp rise has to be higher. I doubt that you will find a smaller, more cost-effective package that can heat that much water that efficiently (90+% AFUE)

If you want to also heat the building, consider going with a regular set of Munchkins, Ultras, Vitodens', etc. and combine them with a Thermax or Triangle-Tube Phase III indirect tank. Again, you'll get more than adequate hot water out of such a system and at very high AFUE as well. It will simply cost more to install because of the added piping, etc.

While neither of these solutions is cheap, they should be less expensive over the long run vs. something like "commercial" water heaters.

Most commercial water heaters I have seen were residential models with a different temp dial to allow higher water temps and little else. Regular water heaters usually have terrible efficiency, low recovery rates, etc. You'll be filling up your mechanical room with buffer tanks until you run out of space and the tenants will still be unhappy.

Cliff Brady

Can waste heat be recovered?

Consider the BTUs you can get back preheating water going to water heater by recovering heat from the waste water. Payback from waste heat recovery could be dramatic and immediate if you can downsize your heaters.

See gfxtechnology.com for more info.