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h.w. unit heaters

bob young
bob young Member Posts: 2,177
Thanks Tim for your input. is this an accepted formula ? i had no trouble doing the math . it seems way too easy ! i always figure for the worst case scenario ! lol


  • bob young
    bob young Member Posts: 2,177
    h.w. unit heaters + boiler

    NEED HELP on this one. best method to figure overall btu size for hot water unit heaters + hot water boiler for closed warehouse 60' x 130' x 15' ceilings. no windows one 8x8 door. concrete block construction w/ flat roof. no insulation. can give more detail on existing system.
  • tim smith
    tim smith Member Posts: 2,738
    heat loss

    ? outdoor and indoor design temp. Then take the temp difference and multiply x .40 for ceiling x sft of ceiling. Then temp diff x .25 x sf for walls. Then permiter slab length x temp diff x 1.19. Then take volume of space x 1 for infiltration. add all together then maybe 15% safety factor, this would probably get you in the ballpark. Also go to Slantfin.com and they have a free heatloss form and use same sq footage and plug in to there calc for a comparison. Copy of link below. http://www.slantfin.com/he2/orderhe2.html
  • tim smith
    tim smith Member Posts: 2,738
    approved method?

    These #s are off equipment sizing form from our local municipality. Using standard #s for U values for generic construction. It will get you in the ballpark. Also double check them with the slantfin sizer. NOTE: these calcs are for the connected load. Then maybe 15% piping and pickup at the most depending on piping arrangement. Good luck, Tim
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