1 2 12
1 10 17

: A

  1. #1

    A



    . .
    , , , , .
    . .
    . ( 80-90 ) , , .


    1 . 9 1&1/4. 4,5 cm : 0,0453,149=1,27 . . 51,30Kcal/mhK 4 mm . . . . ?


    2 1000 80 2,05 10 . 2,15 1. ? 0,041W/mhK watt .
    . 70 10 24 . 40 .
    5 . ?
    (convection trans .) ? .


    3 ? ?
    .





  2. #2

    Dec 2007
    , , Greece.
    :
    4,417
    quote: 9 1&1/4.
    , . , . , .
    , , . , , . buffer 10cm , , .
    , :
    quote: .
    () , ( buffer).


  3. #3
    . . . . . . .


    1) :
    . .. 150mm X 3m 250mm X 6m.
    : 5 .
    .
    200mm X 6m . 24Pa +- 2Pa


    2)
    . 3 . . 5 .




    3)
    . . 20%


    4)
    . ..



    . .


    ,


  4. #4

  5. #5
    Androutso 3cm . ( armaflex) ?

  6. #6
    quote:Originally posted by gregori

    Androutso .
    http://www.isopipe.gr/site/gr/index.php?content=29

    http://udravlikos.gr

    . . 3 XP VISTA. . ? ?


    dimpas KNAUF. . . . .

    : 5 3 . 40 40 7-8 . 8 . .




  7. #7
    quote:Originally posted by androutso
    2 1000 80 2,05 10 . 2,15 1. ? 0,041W/mhK watt .
    . 70 10 24 . 40 .
    5 . ?
    . <<>> 5,0 cm .(10 C ). ; . ;
    10 cm <2 W/C.
    =70 C 70x2= 140 W 24 140 x 24 = 3360 Wh 1000 lit.
    3360 Wh = 2889,6 Kcal = 1000 x => = 3 C.
    80 C 77 C. 70 C. . 80 C 1000 lit 80 C 70 C . .( ) 80 c 30-40 cm . ( !!) 70 C . lit 80 C.
    :

    80X+70(1000-X) = 70*1000 + 2889,6 => X= 289 lit.

    289 lit 289*2,05/1000 = 59 cm , 20-30 cm .


  8. #8

    Dec 2007
    , , Greece.
    :
    4,417
    , : 1000lt , ; , , . , , ! ( ),
    androutso, , 2 4;


  9. #9
    quote:Originally posted by androutso

    1 . 9 1&1/4. 4,5 cm : 0,0453,149=1,27 . . 51,30Kcal/mhK 4 mm . . . . ?
    :
    Do=4,5 cm , Din=3,7 cm , ti= 80 C , to=10 C , ho=10 W/(m^2*K) ( )

    k1= 45,3 W/(m*K) ( )
    =0,94 ( )
    80 C
    cp= 4200 J/(Kg*K), ( )
    k= 0,67 W/(m*K)
    = 3,54x10-4 Pa*sec ( )
    = /=3,8x10-7m^2/sec ( )
    Nu=Din*hi/k = 0.037*hi/0,67 = 0,055*hi
    Pr=cp*/k= 4200*3,54x10-4/0,67 = 2,22
    1000 lit boiler => 25 kW => 21500 Kcal/h =8 C => 2688 lit/h => u=0,7 m/sec ( )
    Re= u*Din*/ =0,7*0,037/3,8x10-7= 68158 ( )
    Nu=0,023*Re^(4/5)*Pr^0,4= 0,023*68158^4/5*2,22^0,4= 232,85 = 0,055*hi => hi= 4233 W/(m^2*K)
    L=1 m :
    R1= 1/(hi**Din*L)= 1/(4233*3,14*0,037*1) = 0,002 K/W
    R2= ln(Do/Di)/(2**k1*L)=ln(0,045/0,037)/(2*3,14*45,3*1)= 0,00069 K/W
    Rc=1/(ho**Do*L)= 1/(10*3,14*0,045*1) = 0,707 K/W
    tos= 78 C =351 K to=10 C=283 K.
    hr =
    hr=**(to^2+tos^2)*(to+tos)=0,94*5,67*10-8*(283^2+351^2)*(283+351)=6,87 W/(m^2*K)
    Rr=1/(hr**Do*L)= 1/(6,87*3,14*0,045*1) = 1,03 K/W
    R3=Rr*Rc/(Rr+Rc)= (1,03*0,707)/(1,03+0,707)= 0,419 K/W
    Rtot=R1+R2+R3=0,002+0,00069+0,419=0,422 K/W
    :
    Qtot=(tin-to)/ Rtot=(80-10)/0,422 = 165,9 W

    :

    tos= ti Qtot*(R1+R2) = 80-165,9*(0,002+0,00069)=79,66 C.

    .

    tos= 79,66 C =352,66 K .
    hr=**(to^2+tos^2)*(to+tos)=0,94*5,67*10-8*(283^2+352,66^2)*(283+352,66)=6,93 W/(m^2*K)
    Rr=1/(hr**Do*L)= 1/(6,93*3,14*0,045*1) = 1,02 K/W
    R3=Rr*Rc/(Rr+Rc)= (1,02*0,707)/(1,02+0,707)= 0,417 K/W
    Rtot=R1+R2+R3=0,002+0,00069+0,417=0,4197 K/W
    :
    Qtot=(tin-to)/ Rtot=(80-10)/0,4197 = 166,78 W
    :
    tos= ti Qtot*(R1+R2) = 80-166,78*(0,002+0,00069)=79,55 C .
    try and error .

    9 : 9*166,78=1,5 kWh , 15 kWh (120 ) = 1800 kWh. = 1800/(3,5/0,85) = 605 Kg 30% .

  10. #10

    Jun 2008
    Glyfada, , Greece.
    :
    3,101


    ! forum . Nu, Pr, Gr . ' .
    , , , ho
    10 W/mK ( 2") 3"

    . ( ) , hi . . ! ' Fundamentals . hi 0,01 m/sec 3 m/sec. .



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