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Type: Posts; User: unclebingo

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    Verify EFLH formula

    Can anyone verify the formula to calculate the Equivalent Full Load Hours for either heating or cooling as being:

    EFLH = 24 x CDD / Delta of indoor design and outdoor 1% Dry Bulb.

    Thanks
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    No, it's a simple 2 bedroom single story home...

    No, it's a simple 2 bedroom single story home with fireplace used for all locations. It's infiltration rate is average.

    I made sure to use the same envelope each time. The only change was the...
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    ManualJ Puzzle of the day

    Using the supplied ManJEd8 spreadsheet, I have performed a number of test calculations in different locations using a default set of controls, and construction envelope.

    The defaults are:
    Indoor...
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    Area / Perimeter Calc

    Anyone run into this little gem?

    www.sketchandcalc.com
  5. Thread: Math Quiz

    by unclebingo
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    I'm pleased my Garbage In has a Carnak Out filter!

    I'm pleased my Garbage In has a Carnak Out filter!
  6. Thread: Math Quiz

    by unclebingo
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    I'm referencing the ASHRAE 2005 Fundamentals >...

    I'm referencing the ASHRAE 2005 Fundamentals > Climate Data > IP Stations > 725450.PDF

    Row:
    Monthly Design Dry Bulb and Mean Coincident Wet Bulb Temperatures

    Column:
    1% Dry Bulb for each...
  7. Thread: Math Quiz

    by unclebingo
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    I managed to find the ASHRAE 2005 Fundamentals at...

    I managed to find the ASHRAE 2005 Fundamentals at my local library but the climate data doesn't include HDD / CDD. So I was hoping I could calculate it by subtracting the 1% Dry Bulb data for each...
  8. Thread: Math Quiz

    by unclebingo
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    Carnak, you were right re Degree Days. Cedar...

    Carnak, you were right re Degree Days. Cedar Rapids has 6924.

    Month 1% dbF Days HDD
    Jan | 45.7 | 31 | 598.3
    Feb | 54.6 | 28 | 291.2
    Mar | 70.6 | 31 | -173.6
    Apr | 80 | 30 | -450
    May | 85.2...
  9. Thread: Math Quiz

    by unclebingo
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    Thanks for laying it all out Carnak, much...

    Thanks for laying it all out Carnak, much appreciated!

    Pity the correction factor can't be calculated... It sounds like it has something to do with octane and elevation?
  10. Thread: Math Quiz

    by unclebingo
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    Cedar Rapids, Iowa But understanding the...

    Cedar Rapids, Iowa

    But understanding the formula is more important to me than just getting you guys to tell me the answer.... I wanna learn!
  11. Thread: Math Quiz

    by unclebingo
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    So the correction factor is only needed if I...

    So the correction factor is only needed if I adopt a standard 97.5% design temp difference?

    I know that the Manual J spreadsheet I have automatically calc's the HTD for me when I enter the...
  12. Thread: Math Quiz

    by unclebingo
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    If I'm using monthly 1% DB data then outdoor...

    If I'm using monthly 1% DB data then outdoor design temp varies from month to month. Does this suggest I need to calc each month?

    What is the correction factor?
  13. Thread: Math Quiz

    by unclebingo
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    I've yet to collect the HDD figures, and for the...

    I've yet to collect the HDD figures, and for the purpose of building the formula I was using default figures from www.hvacopcost.com for both HDD and BTUH loss.

    When I can gain access to the house...
  14. Thread: Math Quiz

    by unclebingo
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    Math Quiz

    Please check my math...

    If my home losses 80000 BTUh, and I live in a region with 3784 Heating Degree Days, then I use 7,265,280,000 BTU per year.
    (BTUh x 3784 x 24)

    Which is 72652.8 Therms...
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    Would you expect the standby, startup and...

    Would you expect the standby, startup and shutdown losses to = 48% of a AFUE 90 furnace?
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    Understood However, after comparing the...

    Understood

    However, after comparing the results from my calc with those of hvacopcost.com a pattern emerges. As efficiency changes, so does the percentage difference between results.

    Variables...
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    78% thermal efficiency = AFUE of 64%

    How can I resolve the thermal efficiency (defined as percentage of fuel converted to heat) from the AFUE rating?

    I understood the AFUE # was the percentage of fuel converted to heat, but the...
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    mchild Many thanks. I believe I have included...

    mchild
    Many thanks. I believe I have included all factors you mention into my calculations. I would appreciate a fresh per of eye's from someone who has completed the process.

    May I send you a...
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    Cost to Operate

    Any Excel guru's with knowledge of how to calculate the cost to operate out there?

    I'm building an Op cost xls, but my results so far are way off those of http://www.hvacopcost.com/

    I'd be...
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    Manual J on monolithic house

    I'm performing a detailed Manual J (Block load only) on a house in Valencia, Spain.
    This home is of a monolithic construction, i.e. it's floors are concrete slabs (poured into forms) and supported...
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    Thanks Pstu I would describe a partition wall to...

    Thanks Pstu
    I would describe a partition wall to separate a conditioned utility room or den in the basement with a garage that sits within the house envelope. In that case there might also be a...
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    So, to clarify. You used HVACCalc to perform a...

    So, to clarify. You used HVACCalc to perform a block load of the house envelope only, rather than performing a room by room load and have HVACCalc total up for a block load?

    Presumably the room by...
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    Block load calculation question

    I'm using the Manual J "MJ8ae v1.08" spreadsheet to calculate the block load of a house.

    Is it possible to perform a block load without entering all room loads, i.e. just enter data about the...
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    ?

    ?
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    Garbage In Garbage Out, right. I've noticed...

    Garbage In Garbage Out, right.
    I've noticed there are disparities between ACCA and ASHRAE data when calculating design grains difference between inside / outside grains.
    Birmingham AL - ACCA
    45%...
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