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Historical Heat Load Calc/ Boiler Sizing methods

InTheLeed
InTheLeed Member Posts: 1
I'm looking for information on some historical methods to both size total systems, and to size the boiler itself to these methods after results are reached for heating demand

Comments

  • Steamhead
    Steamhead Member Posts: 14,476
    The most famous one

    was the "Mills Rule", named for John Mills, one of the pioneering geniuses of steam and hot-water heating. If memory serves, it went like this:



    1. Measure the square footage of glass and divide by 2.

    2. Measure the square footage of walls, ceilings and floors that are exposed to the outside and divide by 20.

    3. Measure the volume of the room in cubic feet and divide by 200.

    4. Add the results of 1, 2 and 3 to get the EDR needed.



    There were other rule-of-thumb methods, but I believe all of them were based on Mills' rule.



    Once you knew your EDR, you would then size your piping to carry the needed amount of steam or water at a very low pressure drop. On steam this meant a drop of 1 ounce in 100 feet for the smaller systems.



    Coal-fired boilers were sized to be able to heat the radiation to its maximum capacity for at least 8 hours on the coldest day of the year, without having to add more coal during that time. This invariably resulted in some seriously oversized boilers, which made things interesting when it came time to convert them to oil or gas!
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,837
    I'm wondering....

    Exactly how accurate was Mr Mills method? Has anyone gone and done a new style loss calc to confirm his numbers?



    To the original poster, what exactly is it that you are looking for? Can you be more specific?



    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
  • Steamhead
    Steamhead Member Posts: 14,476
    edited April 2011
    Dan actually did that once

    it's in his out-of-print book "Ye Compleate Workes of Dan Holohan" which is a collection of articles he had written up to that time. I'll look it up when I get a chance.



    Hey Dan, while I think of it- how about "Compleate Workes, Volume 2"?
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • DanHolohan
    DanHolohan Member, Moderator, Administrator Posts: 15,273
    Worth thinking about.

    Thanks, Steamhead.



    Mark, Mr. Mills' Rule will give you about 19% more than you need.
    Retired and loving it.
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,837
    Thanks Dan...

    Them was some SMART Dead Men.



    How did they know?? Like Gil Carlson, I guess they just "Got it".



    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
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