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Gijs90's avatar
Gijs90
Copper Contributor
Jul 17, 2022

Having trouble getting a formula to work

Hello everyone,

 

I am following a course about engineering coolinginstallations and we have a formula we use to calculate the amount of energy we lose thru an open door.

however i'm having difficulty getting this formula to work in excel.

can anybody help me with this?

the formula is: kf*t*P*A*sqrtH*(1-Pu/Pi)1/2*deltah=Q

everything works except the 1/2 part.

 

example: 0.612*15*1.25*(2*2.5)*sqrt2.5*(1-(1.2/1.25))1/2*72.5=1315.41KJ

4 Replies

  • Adi_Star's avatar
    Adi_Star
    Copper Contributor

    Hello Gijs90 

     

    You can check out the below help document provided by Microsoft:

     

    https://support.microsoft.com/en-us/office/how-to-avoid-broken-formulas-8309381d-33e8-42f6-b889-84ef6df1d586 

     

    Best Regards,

    Adi

  • JoeUser2004's avatar
    JoeUser2004
    Bronze Contributor

    Gijs90  wrote:

    ``0.612*15*1.25*(2*2.5)*sqrt2.5*(1-(1.2/1.25))1/2*72.5=1315.41KJ``

     

    =0.612*15*1.25*(2*2.5)*SQRT(2.5)*(1 - 1.2/1.25)^(1/2)*72.5

     

    results in 1315.40868545317, which rounds to 1315.41.

     

    But note that x^(1/2) is just another way to write SQRT(x).  So another way to write the formula is:

     

    =0.612*15*1.25*(2*2.5)*SQRT(2.5)*SQRT(1 - 1.2/1.25)*72.5

     

    But that could be just GIGO.

     

    Please attach a jpg of the math formula as it appears in your course source so that we can vet your Excel interpretation, in the first place.

     

    And please provide a link to a webpage that has the same math formula with an explanation of it terms.

     

    I tried find it with a google search for "calculate the amount of energy we lose thru an open door" without quotes, to no avail.

  • Riny_van_Eekelen's avatar
    Riny_van_Eekelen
    Platinum Contributor

    Gijs90 Try this:

    =0.612*15*1.25*(2*2.5)*SQRT(2.5)*(1-(1.2/1.25))/2*72.5

     

    Though this returns 131.5409, not 1315.41.

     

     

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