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Lochinvar says, but I am not too sure
Kevin O. Pulver
Member Posts: 380
I'm no math whiz, but the best guys are probably working right now, so here goes!
If you divide by POINT 81 instead of just 81 you get
5,923,555 BTUs. Three of their bad boy ultra fins should cover that. Better recheck this though, thats a LOTTA WATTA! It seems to me though if you have 81 percent efficiency you should multiply the needed BTUS by 1.19 instead of dividing.
I get 192GPM X 60min/hr X 8.33#/gal X 50DeltaT/temp rise which is 4,798,080 X 1.19 equals 5,709,715.
I don't know why mine comes out less. Told you I'm not a math whiz. I get help when I figure stuff, and you're on the right track doing the same! Someone else will come along and straighten us out I expect. Kevin
If you divide by POINT 81 instead of just 81 you get
5,923,555 BTUs. Three of their bad boy ultra fins should cover that. Better recheck this though, thats a LOTTA WATTA! It seems to me though if you have 81 percent efficiency you should multiply the needed BTUS by 1.19 instead of dividing.
I get 192GPM X 60min/hr X 8.33#/gal X 50DeltaT/temp rise which is 4,798,080 X 1.19 equals 5,709,715.
I don't know why mine comes out less. Told you I'm not a math whiz. I get help when I figure stuff, and you're on the right track doing the same! Someone else will come along and straighten us out I expect. Kevin
0
Comments
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BTU/hr required help
Lochinvars engineering formulas show that for water heating the BTU/hr input= GPM x 60 min/hr x 8.33 lb/gal x Delta T divided by percent efficiency.
I have a car wash that flows 192gpm.
If I use (192 x 60 x 8.33 x 50) / 81 (Loch. CWN1795PMF9) I get a required input value of only 59,236 BTU/hr.
This cannot be right.
What did I do wrong??
Mason
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Decimal place.
Divide by 0.81 NOT 81.
4,798,080 btu/hr to heat the water.
At 81% efficiency = 5,923,555 btu/hr.
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Efficiency
should be expressed as a decimal (0.81). So your actual required input would be 5.923 million BTUH.
Hold the Blue Coral, I will be right over!
Brad0 -
SEE?
By the time I got mine posted, several jumped in ahead of me! Kevin0 -
Got the same Numbers BUT................
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Got the same Numbers BUT................
yep, I got those same numbers, BUT they didn;t look right as we are currently heating with a Lochinvar CWN1795PMF9 weighing in at only 1,795,000 BTU/hr.
Could it be that with 480 gallons of storage we are able to meet demand without falling desperately behind, especially since we are never operating at full capacity?
Or oculd it be that with all capacity being used at once, 480 gallons is not depleted before everone gets ther $.25's worth??
Mason
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Storage
Mason, shame on me for not thinking of it but of course storage is your saving grace. I took the heating load as being direct tankless. Your storage buys you time plan and simple.
Of course of your actual flow is 192 GPM all the time it will deplete your tank in 2.5 minutes.
I suspect that you do flow at the 192 gallon rate per minute but not for the full minute and then flowing every other minute ("diversity of load"). Thus you will prolong the capacity and give the burner some rest.
You can play the comparison game between massive input and little storage or more modest input and massive storage. It all comes out in the, ahem, wash.
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Some of us must have
too much time on our hands, eh, Kevin? 0 -
Holy Carwash Batman...
192 guppies per minute is a LOT of water.
Tell us how you arrived at that number, and how large of a water and sewer service do you have feeding the load?
Are you sure it's not Guppies per HOUR, and not per minute???
How many bays, at what flow rate, and reasonably, how many cycles per hour.
Assume a warm Saturday, right after a week of wet sloppy snow, and this Saturday is the Saturday before Easter Sunday. (Worst case scenario, right?!?)
ME0 -
My company designed a carwash years ago
Mark, and I was surprised by the instantaneous flow rate. But like so much of this it is a flow "rate" but only for the time it runs. Wish I remembered the particulars but it was similar to 15 seconds on and a minute between cars or something.
(I was HVAC and support not plumbing so a little removed from the details.)
I thought GPM versus GPH too, but 192 GPH works out to 3.2 GPM. My shower at home does that (thanks to a 1/4" drill in the water conservation device ) 0 -
Caught at the right moment to answer a simple question. 'tis the beauty of the web. Just glad that all the simple answers are in 100% agreement...0 -
They also
use about 85-90°F water max for the wands(Self service bays). Had to add a Sparco on a job to down-mix on one job.
Jed0 -
Mucho DHW
I'd question that number also. The last few washes I have done were Ergomax tanks powered by Clean Burn boilers. Usually 2- 350K boilers will handle washes. Larger washes with an automatic and a few hand wash bays need 3 boilers.
Most of the new automatic tunnel types use very little hot water. The hot goes into tanks to disolve and mix the soaps, everything else is cold water.
You may have a big GPM number considering the cold flow?
Even hand wash bays with 3 gpm flows, wow that's a lot of bays!
hot rod
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You naughty boy Brad!
Don't give your address, the conservation cops will be knocking your door down with a pipe wrench and some JB weld! Kevin0 -
It might not be right,...buh the Cars wont complain*~/:)
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Naughty, Kevin
but clean as a whistle!
Pass the soap please.
Brad0 -
Yous Guys
You guys are simply the best. When one of us has a question or problem, you're all there to help.
Back to the flow question, I am going on "stated" information. I have 8 self-serve bays at 10 gpm and 2 automatics at 56 gpm each for a grand total of 192.
Of course thsi does not run all the time, but no one in the car wash biz can seem to tell me or is willing to tell me how to figure what I need for a flow rate.
Like I said earlier, I do have 480 gallons (476 actual) of storage in four Loch. 120's.
I would like to engineer some redundancy into the system, and maybe go with a flat plate sor something similar to keep from destroying the heat exchangers with our lovely water quality.
Mason
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Drillem out
I do that too. Nobody likes lo flo showers or kitchen faucets either. Come get me **** Nixon and your EPA.0 -
Since you guys are already here, I have a question....
I was just out at a wash, but this ws no dinky carwash, but a truck wash for Semi's.... two bays, with trucks lined up around the property waiting to get in! I was diagnosing a couple of problems there and was wonderng if some more efficient heating equipment could be used. The target supply temp is only 110F and the inlet temp typical, about 50F. They are using a couple of sizable Raybacks pumping into a smallish buffer tank. What's out there in direct fired condensing Domestic water heating units. Oh and the water is seriously softened.....hardness roughly zero.
Thanks folks
Boilerpro0 -
BP
seems any of the condensors that allow DHW production. Munchkin, and soon Lochinvar offer DHW versions of the condensors. Seems you could stage a few if that demand is variable.
Direct to a condensing boiler, without a heat exchanger, would be the most efficient method I could think of.
I would check the ph of tht water however. If they use RO it could be harmful to that boiler.
What about those heaters where the flame actually goes into the water. Wonder what type of efficiencies those runs. Hard to beat fire within the water. Maybe?
hot rod
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Mason, not
to second guess you but 10 gpm sounds way high for a hand wash bay. Try and fill a 5 gsllon bucket at a hand wash sometime I think the high pressure hand wands run more like 1- 3 GPM??
10 gpm at 1500- 3500 psi would be a hell of a wand to hang on to.
hot rod
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Thinking along the same lines
No heat exchanger to increase operating temperature and those direct flame units are used in the concrete industry....Hotsy is one of the locals. I need to keep researching.
Thanks for your input
Boilerpro0 -
Where?
I've heard of those flame in the water things at the concrete batch plant. Never seen one though.
Any websites to look around? Kevin0
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