October 24, 2014

Is a cooling tower a worthwhile investment? (part 3)

Now let's see how we calculate the size of the tower with the available data:

Let's suppose that the water flow rate is 15 – 20 - 25 m3/ (m2 h), hence we have the size (top view) of the tower. We also have the market price and, hence, the price of the tower.

For the cost of fan power, let's assume an air velocity of 3.5 m/s. We therefore know the air flow rate to the fan and let's assume the yield value of the impeller at 70%. It's now possible to calculate the power absorbed in kW that will be useful to determine the fan power cost.

Using the same method we can also calculate the power absorbed by the pump for the water circulation.

The cost of the installation is calculated to be as much as the cost of the tower.

Calculations of the cost for the installation of a cooling tower
m2 tower (20 m3/h m2 approx.)
1.26
Cost of the tower
7,536,000
Cost for installation
7.536,000
Total cost
15,072,000
Calculation of the cost for the power of the system with tower
Energy Consumed

motor fan motor kW
1.05
air flow rate
13,565
prevalence mm CA
20
motorfan yield
70%
pump motor for the movement of water
5.42
water flow rate
25,12
prevalence m AC supply
30
yield of the pump
70%
Total kW for circuit tower kW / year
12,413
Cost of electricity per year
1,241,281
Cost for the make-up water calculated to 5%
m3 / h
1.3
Cost of make-up water
2,411,520
Cost bleed-off water (= make-up / 2 x cost of water purge)
602,880
Cost of maintenance of the tower 5% of the installation cost
753,600
Total operative costs
2,597,761
Costs Evaluation
Cost with aqueduct water in one year
36,172,800
Operating cost of the system with tower
2,597,761
Savings in one year
33,575,039
Savings each month
2,797,920
Total cost of the tower
15,072,000
The investment return (ROI) in MONTHS
5,4


Here we can see that the ROI payback period for the tower installation is only 5 and a half months. Because of the small entity involved, financial costs were not taken into account.


All of the above calculations are available upon request. For more information contact us. 

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