3 9 12345 ...
21 30 90

:

  1. #21

    Jun 2008
    Glyfada, , Greece.
    :
    3,101


    quote:Originally posted by DDD

    . . , . ( ).
    . .
    ; . .
    ,

    , , extra , extra-extra , , , , : upward facing cooled horizontal plate , (convection) . , 20 29 7,42 W/mK, 7,42 9 = 67 W/m. 9 W/mK 81 W/m. UNI EN 1264. (' ) : 18 20. 67 W/m ~82 W/m ( ).
    - .
    1. dissatisfied. 22 20 : 67 W/m 58 Kcal/hm. 6 .. 350 . ; . 700 1000 . ; ( ). .
    2. 22 23 . .....
    3. 15% . ; ; ( ), ; . handbook

    : spacing ! . . , spacings, , , W/m 82, 80, 85 ( 30 . 174 178 handbook Blasir .
    , , ( 70 . ..), 4 . . 29 10%.
    ASHRAE.






  2. #22
    Super Moderator DDD's Avatar
    Jul 2007
    Athens, , Greece.
    :
    1,695
    quote:Originally posted by Pirate


    . .
    ; . .
    ,
    ; , ; . 100W/m2 . ( ) . " " : " " " " . ; .

  3. #23

    Jun 2008
    Glyfada, , Greece.
    :
    3,101
    post. . topic , :
    --- ,
    --- , . , .
    --- , .
    --- , .
    --- ...

    : : 82 W/m. ! ( 100 W/m , 100 31 10%, 20%).
    . . ' .




  4. #24
    Super Moderator DDD's Avatar
    Jul 2007
    Athens, , Greece.
    :
    1,695
    quote:Originally posted by Pirate



    : : 82 W/m. ! ( 100 W/m , 100 31 10%, 20%).
    M EN1264-2 EN. 29 20C 100W/m2. q(g) ( ).

    Tr20-Tf29

    Tr20-Tf35

    Tr24-Tf33

  5. #25

    Oct 2005
    Nikea, , Greece.
    :
    2,979
    , . "" . "";
    . . ( ) .

    .
    .



    Should array indices start at 0 or 1? My compromise of 0.5 was rejected without, I thought, proper consideration. (Stan Kelly-Bootle)

  6. #26

    Jun 2008
    Glyfada, , Greece.
    :
    3,101
    ; .
    :
    =29 =20. .
    [u]1. :
    (convection) ASHRAE : (3 . label: ).
    ------------------------------------------------
    Horizontal cooled plate facing upward:
    Nu=0,27XRa^0,25 for 10e5 < Ra < 10e10 & Nu=hXL/k & L=A/Per A--> floor area & Per-->floor perimeter
    Ra=GrXPr, Gr=g....L^3/, Pr=cp./k
    20 :
    g-->9,8 m/sec
    --> = 0,0034 K^-1
    --> = 1,19 kg/m
    k--> = 0,0253 W/mK
    --> = 18,26 Pa.sec
    cp--> . = 1006 J/kgK
    :
    Pr=0,726 & Gr=1,273e9 & Ra=9,25e8 (Ra<10e10) & Nu=47,1
    : hc = Nu.k/L = 1,2 W/mK
    [u]2.
    =0,95 (29 - 18) :
    hr=..(+)(+) --> Stefan-Boltzmann = 5,67-8 W/m^4
    hr=5,38 W/mK
    , hc+hr=h=6,38 W/mK .
    --------------------------------------------------
    :
    20 18 7,43 (29-18) = ~82 W/m. 24 33 7,439 = 67 W/m qg , . 100,012 W/m. ! 67 W/m. ; . 33 34 ( ) ( ).
    ( ) ...! ....




  7. #27
    .
    1) 67 W/m 57,62Kcal/m 2,80m 57,62/2,80=20,58 ; ; ... ;
    2) ; " " .. .

    .

  8. #28

    Mar 2009
    Deventer, The Netherlands
    :
    Lead Consultant
    585
    ,
    ASHRAE h=1,32*(/L)^0,25 h=2,29 W/m2K .

    20 , 24,5 (29+20/2).

    , 20, . , .

    , , .

    , .

    ASHRAE h ?

    h 11 W/m2K 29-20 * 11= 99W/m2

  9. #29
    Super Moderator DDD's Avatar
    Jul 2007
    Athens, , Greece.
    :
    1,695
    q(g) (, , ). 1m , h x A, h . ( film ). h , 1m 20C. . .

    18; 29 20. 18C.

  10. #30
    Super Moderator DDD's Avatar
    Jul 2007
    Athens, , Greece.
    :
    1,695


    quote:Originally posted by CONSTANTINOS


    2) ; " " .. .
    .

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