Cooler CO-201 Menentukan jenis Cooler

 Reynold number, Re a Pada t av = 86 o F  = 0,7076 lbjam ft Re a =  a e G x D = 0,7076 623 1.121.542, 0,1312 x = 207.951,3739  jH = 400 Gambar.24, Kern  Pada t av = 86 o F k = 0,3538 Btujam ft. o F cp = 1,0541 Btulb o F 3 1        k c  = 3 1 0,3538 7076 , 1,0541        = 1,282  hoΦ a = 3 1              k c D k jH  = 400 x       0,1312 0,3538 x 1,282 = 1.382,84 Btujam ft 2 o F  Reynold Number, Re p Pada T av = 189,5 o F  = 0,2661 lbjam.ft Re p =   Gp Dp = 0,2661 15 287.622,02 0,1723 x = 186.235,5291  jH = 380 Gambar.24, Kern  Pada T av = 189,5 o F k = 0,0838 Btujam ft. o F cp = 2,4915 Btulb o F 3 1        k c  = 3 1 0,0838 0,2661 2,4915        = 1,7120  hiΦ p = 3 1              k c D k jH  = 380 x       0,1723 0,0838 x 1,7120 =316,407 Btujam ft 2 o F hioΦ p = hiΦ p x       OD ID = 274,7955 Btujam ft 2 o F  Temperatur dinding T w T w =   c c a p a c t T x ho hio ho t       =   86 5 , 189 1.382,84 274,7955 1.382,84 5 , 189    x  Pada t w = 293,8342 o F w = 0,3084 lbjam ft. Φ a = w 0,14 = 0,70760,3084 0,14 = 1,1233  Koreksi koefisien ho ho = hoΦ a . Φ a = 1.382,84 x 1,1233 = 1.553,3442 Btujam ft 2 o F = 293,8342 o F  Pada T w = 293,8342 o F w = 0,2931 lbjam ft. Φ p = w 0,14 = 0,26610,2931 0,14 = 0,9866  Koreksi koefisien hio hio = hioΦ p . Φ p = 274,7955 x 0,9866 = 271,1132 Btujam ft 2 o F Sehingga didapat Clean over all coefficient, Uc o io o io h h h h Uc   . 1.553,3442 271,1132 1.553,3442 271,1132   x Uc = 230,826 Btujam ft 2 . o F  Menghitung Ud Design Overall Coefficient Rd = 0,001 hr.ft 2 . o Fbtu Tabel 8. Kern, 1965 Ud 1 = Rd Uc 1  Ud 1 = 001 , 230,826 1  Ud 1 = 0,0053 Ud = 188,6792 Btuhr.ft 2 . o F  Menghitung A surface area required A = t . U Q D  = 80,5263 188,6792 2 617.743,24  = 40,658 ft 2  Menghitung jumlah hairpin External surface lin ft, a = 0,917 ft 2 Tabel.11 Kern, 1965 Required length , L = a A = 9170 , 40,658 = 44,338 ft Panjang hairpin = 12, 15, 20 ft Kern, 1965 Diambil L h = 20 ft 1 hairpin terdiri dari 2 pipa n = 2, maka jumlah hairpin yang diperlukan : Hairpin = h 2.L L = 20 2 44,338  = 1,1085  2 Maka jumlah hairpins yang digunakan = 2 buah Koreksi panjang pipa : L kor = 2.L h x hairpin = 2 x 20 x 2 = 80 ft linier