Indirect Tank Manufacturers, please read.

ALH_4

I would love to see technical data sheets from all manufacturers similar to what <a href="http://www.viessmann.ca/web/canada/ca_publish.nsf/AttachmentsByTitle/dbl-vitocell-v-300.pdf/$FILE/5167-410-v2-VitocellV-300-TDM.pdf"target="_blank">Viessmann</a> publishes.

Unknown

Ok, IDFWH manufacturers.

I am tired of clients of mine calling up tech support, and being told a given boiler is "too small" for a given tank.

You guys build these tanks. Is it too much to ask that your tech guys have a little calculator on their computers? Where they can plug in domestic load, boiler output, tank size, and get an estimate on how it will perform?

SOMETHING more than a guy reading a chart and assuming that if there is an 80 gallon tank present, that OF COURSE we are trying to meet it's first hour or continuous ratings as charted in the sales lit? I mean, we'd NEVER upsize storage to avoid upsizing a boiler, right???

Seriously, this is really ticking me off. I expect MFGs to have slightly more advanced knowledge about their own products than what we can read off of the sales lit.

Dave Yates (GrandPAH)_8

It would also be great

if the industry adopted a standard set of cold-water temperatures that more realistically reflected real-world conditions and then utilized the actual weight of that cold water in those hourly recovery rates. One mfgr is using what could best be described as the PR-weight per gallon, or what I'd call lite-water, (the weight per gallon at 140F!) to artifically boost their recovery rates.

ALH_4

Ratings

I had one manufacturer tell me that their double-wall heat exchangers had a higher first hour rating because it had twice as much tube.

All I was thinking as he was telling me that was that half of the tube is inside the other tube and should hurt the rating. I gave up on them at that point.

jp_2

no real world number

dave,

thats the problem, there is no real world single number thats going to work for everyone. whats real world from north carolina to northern minnesota? nothing exists!

the other day I measured incoming water at 46F. how does that compare to your measurements?

so lets talk about heatloss, most manufacturers claim 1/2F loss per hour, thats pretty vague if you ask me.

what needs to be clearly stated is the conditions under which all their specification determined.

Unknown

if they even specified the average delta-T across the heat exchanger, that would make me even happier.

But really my issue is with the tech-lessness of their tech support. I mean, really. I know they are tanks, so you don't need Phds on the tech line, but someone who can operate a calculator and ONE person in the company who can write one in excel would be fine...

Mitch_4

would this work?

Do not do a lot if indirects as the gas utility here used to rent tanks and EVERYONE has em.

incoming water 45°, out 140, delta = 95° 1 US gal = 8#, 40 gal tank holds 320# 320# x 95 = 30400btu to recover 40 gals, double the recovery, 60800.

All based on 100% transfer.

Pump GPM x 8 (# in a gal)x 20° delta tee x 60 determines the # of btuh per hour delivered to the tank. So if the pump is running @ 6gpm we get 6x8x20x60 57600 btu/hr delivered,Enough for about 60 gallons recovery .

the lit states for the tank I am looking at that 40 gal @69000 btu and 6GPM will recover 130+ gallons. but based on only a 75 deg rise and 60 inlet water...

Don't trust the lit..

Do these formulas make sense? I am still learning (GODS THERE IS SO MUCH!!!)the hydronics, hoping to start doing more

Dave Yates (GrandPAH)_8

actually

There are pretty standard bottom-line cold-water delivery temps. Around the country, we bury incoming water lines at depts dictated by frost. Consequently, 40F is an almost universal lowest delivery temp no matter where you live for municipal water systems.

For well-water, 55F is the norm.

However, if anyone wants to say they don't see anything lower than XYZ temps, then a chart like Takagi's with bullet-points detailing GPMs based on incoming water temps would be the way to go. At least we'd be armed with the facts.