Are my edr calculation correct...PLEASE help

AJ1

I am in the process of sizing a gas fired steam boiler...are my calculation for total EDR correct...

Please help..

also do I need to multiply the total by 1.33 to get the final edr..is this factor of 1.33 needed..

I am also attaching photos of the radiators in case my calculations are off...I was taken into account 2 column and 4 tubes..in my calculation..

my calculations are here..



<a href="https://spreadsheets.google.com/ccc?key=0AoRHjdMocm80dHBTWmJIWXJTMlpBaEFmQXI1UUQyOXc&hl=en&authkey=CMKSstAJ">https://spreadsheets.google.com/ccc?key=0AoRHjdMocm80dHBTWmJIWXJTMlpBaEFmQXI1UUQyOXc&hl=en&authkey=CMKSstAJ</a>



I came to the total of 269 Sq FT EDR without the 1.33 facto and therefore looking at the boiler spec sheet it is giving me a IBR Net Rating Steam (BTU/hr) 64000.



Also in the trade when they say you need a 85000BTU/hr boiler do they mean DOE heating capacity or IBR.

Dave in QCA

EDR and BTU

The EDR rating of a boiler already has the piping and pickup facter figured in.  You simpley match a boiler to your EDR.  If you are using your BTU figures, you would either match your system BTU to the NET BTU rating on the boiler, or take your system BTU x 1.34 and that should match up to the Output (gross) of the boiler.



I hope that makes sense.

Steamhead

That column radiator

looks like an H.B. Smith "Princess" which has a higher EDR per section than the usual type. So if they're all like that, the living room would be 3 SF per section, or 33 SF. The drawing room would be 2.6 SF or so, for 28.6 SF (23" Princess rads don't appear in my charts) or 57.2 for the pair. The foyer would be 4 SF/section for 24 SF, or 48 for the pair. If you can find a name on those column rads, that will help.



The wall rad, if each section is 22x13 inches, is 7 SF per section, or 56 SF.



The tube rad shown is a small-tube rather than large-tube, 1.8 SF per section. The 6-section of this type is 10.8 SF, the 10-section 18 SF, or 36 SF for the pair.



So your total would be 241 SF. You don't need to add a pickup factor when looking at boilers, since that's already figured into the Steam Square Feet rating. A Burnham MegaSteam 288 for oil or Smith G8-S-3 for gas would serve this system very well.

Dave in QCA

looked like small tube to me too, but....

If they the tube style radiators measure 1.75 inches for the width (thickness) of each section, they are small tube radiators.  However, my table differes from Steamheads.  For a 4 tube x 25" tall smalltube radiator, I show 2 sq ft/section.  My table shows 1.6 for a 3 tube, perhaps Steamhead looked at the wrong line on his chart?

I am attaching my file from an old ASHRAE guide book.

AJ1

thank you

all for your help...

One last question...I am looking at the boiler spec sheet and in one column it says Input (Btu/hr) and for 270 SQ FT IBR Steam this value is  103 (BTU/hr).



Refer to Model number BSI103 in the attachment.



Does this means that I will consume 103 GAS THERMS if I operate this boiler for one hour.



Reason for asking is,that I am trying to find out what my gas bills would be like..if I go with this boiler..

Mike Kusiak_2

Therms vs. BTU

If the boiler spec for input is 103, 000 BTU/hr, them this corresponds almost exactly to a fuel useage of 1 therm per hour. Of course this only applies while the boiler is being fired, and under normal conditions it will not fire continuously. The boiler will cycle on and off under the control of the thermostat and pressuretrol to meet the actual heat requirements of the building.