An induced-draft cooling tower cools 90,000 gallons per minute of water from 84 to 68oF. Air at 14.61 psia, 70oF dry bulb and 60
oF wet bulb enters the tower and leaves saturated at 80oF. Find (a) the volume flow rate of air in cubic feet per minute, and (b) the makeup water required, in lbm/hr.
1 answer:
Answer:
a. V = 109.64 × 10⁵ ft/min
b. Mw = 654519.54 kg/hr
Explanation:
Given Parameters
mass flow rate of water, Mw = 90000g/min = 6607.33 kg/s
inlet temperature of water, T1 = 84 F = 28.89 C
outlet temperature of water, T2 = 68 F = 20 C
specific heat capacity of water, c = 4.18kJ/kgK
rate of heat remover from water, Qw is given by
Qw = 6607.33[28.89 - 20] * 4.18
Qw = 245529.545kw
For air, inlet condition
DBT = 70 F hi = 43.43 kJ/kg
WBT = 60 F wi = 0.00874 kJ/kg
u1 = 0.8445 m/kg
oulet condition,
DBT = 70 F RH = 100.1
h1 = 83.504kJ/kg
Wo = 0.222kJ/kg
check the attached file for complete solution
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Answer:
F=531831381
Explanation:
There are two ways of doing this question:
1) By Formula
2) By Using Compound interest Table
By Formula:
Where:
F is future value
A is annual amount per year
i is interest rate
n is number of years
F=531831381
By Using Compound interest Table:
F=A(F/A,i,n)
From Table F/A at i=8% and n=8 is 10.6366
F=50000000*(10.6366)
F=531830000≅531831381
The difference in two answers is due to decimal points if you take value from table to greater decimal points you will get the exact answer as by using formula.