Tugas Ekotek Soal 6.1 1. The purchased cost of a shell-and-tube heat exchanger (floating head and carbon-steel tubes) with 100 ft2 of heating surface was $3000 in 1980. What will be the purchased cost of a similar heat exchanger with 200 ft2 of heating surface in 1980 if the purchased-cost-capacity exponent is 0.60 for surface area ranging from 100 to 400 ft2? If the purchased-cost-capacity exponent for this type of exchanger is 0.81 for surface areas ranging from 400 to 2000 ft2, what will be the purchased cost of a heat exchanger with 1000 ft2 of heating surface in 1985? Ans : A. Shell and tube heat exchanger
:
type : Floating head and carbon steel prize : $3,000 in 1980 Heating surface area : 100 ft2 Purchased cost capacity exponent : what will be : same type Heating surface area : Purchased cost capacity exponent (n) :
Prize for 200 ft2 =
200 ft2 0.6
0.6 for ranging area
100-400
ft2
for ranging area n
100-400
ft2
0.6 for ranging area
100-400
ft2
for ranging area
100-400
ft2
$4,547.15
B. type : Floating head and carbon steel prize : $3,000 in 1980 Heating surface area : 100 ft2 Purchased cost capacity exponent : what will be : same type Heating surface area : Purchased cost capacity exponent (n) :
400 ft2 0.6
n
Prize for 400 ft2 = index year index year
$6,892.19 1980 = 1985 =
560 790
what will be : same type Heating surface area : Purchased cost capacity exponent (n) : in 1985
Cost =
$20,423.38
Cost???? 1000 ft2 0.81 for ranging area
400-2000 ft2
Soal 6.2 2. Plot the 1985 purchased cost of the shell-and-tube heat exchanger outlined in the previous problem as a function of the surface area from 100 to 2000 ft2. Note that the purchased-cost-capacity exponent is not constant over the range of surface area requested. Ans index year index year
1980 = 1985 =
type : Floating head and carbon steel prize : $3,000 in 1980 Heating surface area : Purchased cost capacity exponent : Purchased cost capacity exponent (n) : with same equation as previous problems : Range capacity Cost in year 1980 Cost in year 1985 100 $3,000.00 $4,232.14 200 $4,547.15 $6,414.73 300 $5,799.55 $8,181.50 400 $6,892.19 $9,722.91 500 $8,257.61 $11,649.13 600 $9,571.75 $16,178.09 700 $10,844.71 $21,246.68 800 $12,083.47 $26,822.02 900 $13,293.06 $32,877.47 1000 $14,477.34 $39,390.87 1100 $15,639.28 $46,343.33 1200 $16,781.29 $53,718.52 1300 $17,905.35 $61,502.12 1400 $19,013.08 $69,681.41 1500 $20,105.86 $78,245.03 1600 $21,184.87 $87,182.68 1700 $22,251.14 $96,485.03 1800 $23,305.55 $106,143.52 1900 $24,348.88 $116,150.28 2000 $25,381.83 $126,498.05
560 790
100 ft2 0.6 0.81
ranging area ranging area
100-400 ft2 400-2000 ft2
Capacity Vs Cost $140,000.00 $120,000.00
Cost in 1985
$100,000.00 $80,000.00 $60,000.00 $40,000.00 $20,000.00 $0.00 0
500
1000 Capacity
1500
2000
