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  1. #1
    Join Date
    Jun 2018
    Location
    TX/ LA border
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    Cooling load calculation and Insulation ? Hot/ Humid Pole barn shop

    Hey all, new here.

    Building a new 40x40x10 wood frame pole building to be used as workshop.

    Hot/ Humid TX/LA border, 100 mile N of Coast.

    Questions on AC load and insulation.

    Will have 6" fiberglass in walls, and 9" in ceiling. - Vinyl perforated faced 5' wide rolls, steel banding support system.

    Plan on two 24kbtu "window" Ac's mounted in wall sleeves, opposite corners of the building.

    Yes, believe me I have done hours of reading at ORNL, FL Solar, US DOE,Building Science, etc... but still have question---

    If my put my 9" overhead fiberglass against the underside of roof steel (4/12 pitch Trusses, 5'0" OC) -VS- between the Bottom Chords of trusses at approx 10' elevation..... How would it affect my cooling $ billing ?

    Not a $ amount, but like a semi educated % diff between the two insul placements.

    Roof peaks at approx 17', bottom of truss approx 10' above slab.

    The cube ft difference is - Below 10' - 16,000ft3, above the 10' elevation.. the area within the Trusses - approx 5600 ft3.

    So, total cubes of 21,600 if I have the insul under the roof, 16,000 if at 10' ceiling level.

    There are other advantages and disadvantages, but still want to know how the cubic area will affect my power bill.

    Also, seems to me two 24kbtu windowshakers is enough... maybe too much actually, but want two for faster cooldown, maybe run one as needed, also just plain redundancy if one dies.

    I am not interested in Minisplit or ducted "Central" AC.

    The two Friedrich 24kbtu (Chinese though, no more US made window units for like 15 yrs now) will run me $.

    NEED to get this decided next few days.

    Thank you all, Marc
    Last edited by beenthere; 06-15-2018 at 04:50 AM.

  2. #2
    Join Date
    May 2006
    Location
    Philadelphia, PA
    Posts
    1,800
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    Have a proper load calculation performed and install one or two mini-splits. Make sure the roof is white.
    Climate Control Solutions for your Home or Office

    Serving Northeast Philadelphia and Surrounding Areas

  3. #3
    Join Date
    Jun 2018
    Location
    TX/ LA border
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    Thread Starter
    Quote Originally Posted by comfortdoc View Post
    Have a proper load calculation performed and install one or two mini-splits. Make sure the roof is white.
    I should have added - R Panel roof is White.... Not interested in mini splits.. have no one to do calc.. Manual J and T not findable free online...and I am not familiar w using them.. that is why I am posting here.

    I am not asking for anyone to do an actual calculation.. I'm not an HVAC guy, but being a retired Electrician, I'm pretty sure real world oriented on the ball old timers will be able to estimate my answers from experience.

    Thank you for reply.

    Marc

  4. #4
    Join Date
    Mar 2013
    Location
    Billington Heights, NY
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    Quote Originally Posted by comfortdoc View Post
    Have a proper load calculation performed and install one or two mini-splits. Make sure the roof is white.
    im pretty sure he doesnt want a mini split. (did you even read his post?)

    im also pretty sure he's trying to get a basic load calc done on here, but he can also try: loadcalc.net
    This forum requires that you wait 20 seconds between posts. Please try again in 50 seconds.

    Experience - knowing when to get the hell out of the way and plug your ears. "Don't be a sissy. Turn it on!"

    Poodle Head Mikey - "the world is well populated with the unknowing and the uncaring and the stupid."

  5. #5
    Join Date
    Jun 2018
    Location
    TX/ LA border
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    Thread Starter
    Can't edit original post - Roof R panels are White, semi shaded by tall trees location... south side of building basically totally shaded.

    Basic stock "insulated" overhead doors, no windows or skylights.

    NO ceiling fans stirring up stratified air.


    Mostly most important wondering how IF I include the added vertical height "Attic" area IN the conditioned space, approx ballpark how much higher will my cooling bill be?

    Thank you again, Marc

  6. #6
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    8,209
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    R-18 Walls … using R-3 per inch
    R-27 Ceiling

    The Surface Area ( not volume) determines the heat transfer.
    Volume (heights & widths) will impact stratification.

    Q. ceiling = dT * Area / R

    Q. underside of roof = 1.31 * Q. ceiling __ Minimal difference: MAYBE Increase ~ 900 BTU/HR

    ___________________

    Overhead doors and Amount of infiltration
    based on construction quality will have Major Impacts.

    LATENT LOAD IN TX/LA REGION WILL HAVE A HUGE DETERIMENTAL IMPACT.

    In other words, humidity could well be really OUT-OF CONTROL with window units.


    YOU CAN PAY FOR THIS ANALYSIS
    BY SUPPORTING GARY at
    - www.loadcalc.net -


    $$$$ __ ___ $$$$



    ------
    The surface area of flat ceiling is 1,600 sq feet vs 2,100 SF of Roof underside.

    17 289 22 27 0.8148
    20 400 1600 1303.7
    689
    26.2488 1711.0
    52.497
    40
    2099.9
    1.3124

    https://www.greatdayimprovements.com...lue-chart.aspx
    Attached Images Attached Images   
    Last edited by dan sw fl; 06-15-2018 at 02:16 AM.
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  7. Likes Marc Jesske liked this post
  8. #7
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
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    APPROXIMATE OPERATING COST
    Attached Images Attached Images  
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  9. #8
    Join Date
    Jan 2004
    Location
    PA
    Posts
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    What kind of equipment will you be using in this new shop. That can add to the cooling load also.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  10. #9
    Join Date
    Jun 2018
    Location
    TX/ LA border
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    Thread Starter
    DanSWFL - Sent you email at 5:30 am ct Fri morn.

    Check your Spam.

    Marc

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