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Thread: Calculation

  1. #1

    Calculation

    Trying to figure out how to calculate how much hot water was produced but it is not metered, however I have natural gas usage.
    I was told there is a formula to calculate this, but I cannot seem to get it right.

    Thanks!

  2. #2
    Join Date
    Jul 2008
    Location
    Denver, CO
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    4,205
    I'm confused are you trying to find the recovery rate for your water heater?

  3. #3
    Sorry, no.
    This is in regards to a commercial boiler.
    Natural gas is used for the boiler and I know how much water goes into the facility by meter, but I want to know how much of that (gallons) is hot water produced by the boiler.
    There is no meter for this, all I have is the natural gas used for the boiler and was told it can be calculated using this figure.

    Thanks.

  4. #4
    Join Date
    Oct 2009
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    Mukwonago, WI
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    no way to tell really, put a meter on the water heater.

  5. #5
    Join Date
    Aug 2008
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    27
    KDC:

    I may be able to help. Please send a follow-up:
    1. Is this a summer- winter hookup, wherein the boiler provides domestic hot water?
    2. If so, do you have (or can you obtain) 12 months' gas usage?

    The boiler manufacturers all boast about efficiently producing domestic hot water (DHW) from an appliance that's usually grossly oversized for the DHW load; I haven't seen many instances where a separate water heater didn't do better in mild or hot weather.

    Ferd/Fred

  6. #6
    Join Date
    Aug 2000
    Location
    Central Oregon
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    749
    I know there's a way to tell a btu output by the gas meter. It's a simple calculation that can be gotten from the gas company. You simply count the meter rotaions for 1 minute and multiply it by a number I cant recall. But to figure out how much hot water is produced. I think the boiler manufacture has all that come to think of it. Unless your questioning their claims.
    If you think our goverment is screwed up. You haven't lived in another country.

  7. #7
    Join Date
    Jan 2004
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    Lancaster PA
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    If you know the BTU content of the gas(or therms consumed). The efficiency of the boiler.
    The entering water temp. And the water temp leaving the boiler.
    You can calculate pretty close.

    ((BTUs of gas consumed X efficiency)/water temp rise)/8.33=gallons of water heated.

    EG:
    10,000,000 BTUs X 75% efficiency = 7,500,000 BTUs / 60°temp rise(use your actual temp rise) = 125,000 pounds of water heated(by 60°) / 8.33(pounds to the gallon of water)=15,006 gallons of water heated.

    Presuming that the boiler only heats fresh water.
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  8. #8
    Join Date
    Nov 2008
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    Quote Originally Posted by kdc23 View Post
    Sorry, no.
    This is in regards to a commercial boiler.
    Natural gas is used for the boiler and I know how much water goes into the facility by meter, but I want to know how much of that (gallons) is hot water produced by the boiler.
    There is no meter for this, all I have is the natural gas used for the boiler and was told it can be calculated using this figure.

    Thanks.
    1 BTU raises 1# of water 1F.
    Water is 8.3# per gallon.
    100 cu. ft of NG gives 100,000 BTU.

    Incoming water is at what temp?
    How hot is outgoing water?
    How much water do you use per day, week, month?
    How much NG do you use per the same period?

    Now that I've posted, Mr. There beat me to it. And, I forgot to include efficiency.

  9. #9
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    Jan 2004
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    It took you 31 minutes to post that.
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  10. #10
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    Quote Originally Posted by beenthere View Post
    It took you 31 minutes to post that.
    The roomful of naked women here must have distracted me. . .

  11. #11
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    Quote Originally Posted by WhoIsThat? View Post
    The roomful of naked women here must have distracted me. . .
    Ok, thats a good reason.
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  12. #12
    Now now... .gentlemen... all the ladies will just take your money anyhow!

    Thanks for the info.
    I was thinking along those lines but missed the efficiency. Now that you mention it thats what I was missing. I have the monthly therms and knew the water was 8.#/gal and the conversion to BTU... I just wasnts sure what I was missing. It was definitely the efficiency. Will check with one of our guys on the boiler efficiency and let you know if that works out.

    Thanks to all.

  13. #13
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    Quote Originally Posted by kdc23 View Post
    Now now... .gentlemen... all the ladies will just take your money anyhow!

    Thanks for the info.

    Thanks to all.
    Send more money.
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