Continuing from previous post on structuring the available data for calculations ...
So,
let's start with the following data:
Data
from within the company
|
|
Amount
of water from aqueduct m3/h
|
12,56
|
Hours
per day
|
8
|
Days
per week
|
5
|
Weeks
per year
|
48
|
Cost
of Water and Power
|
|
cost
primary water (1)x/m3
|
1000
|
cost
waste water (1)x/m3
|
500
|
cost
of kW / h
|
100
|
Calculation
of the cost of aqueduct water per year
|
|
Cost
of water used
|
|
Primary
aqueduct water m3/year
|
24,115,200
|
For
the waste water
|
12,057,600
|
Total
cost of water used in one year
|
36,172,800
|
Now
we will estimate the cost to design the system. If consists of:
- Cooling Tower
- Installation (materials included: pipes, valves, etc.)
- Cost of operation (maintenance, replenishing water energy)
Let's
now try to estimate the cost of the plant with the tower:
Suppose
that:
- the water flow in the tower is twice as much with respect to the system with water waste (the temperature difference between the incoming water and the outgoing water from the system will be about half)
Example:
Water
without cooling tower:
Actual
water flow rate: 30 m3/h
Inlet
temperature by the system: + 15 ° C
Outlet
temperature by the system: + 25 ° C
With
cooling tower:
Water
flow rate: 60 m3/h
In
worst weather condition: summer
Inlet
temperature by the system: + 30 ° C
Outlet
temperature by the system: + 35 ° C
Let's
suppose that the water flow rate is twice as much as the one used by
the plant with aqueduct water (the difference in temperature between
the water entering the system will be about half from the one exiting
the system).
Another
thing to decide about a plant with cooling tower
is:
- high efficiency (the water temperature leaving the tower to serve the system)
- medium efficiency
- to dispose only heat from users (water temperature leaving the cooling tower is not important)
We
can now combine all the above data because we have sufficient
elements to determine the physical size of the tower. To make a cost
estimation, keep in mind that the market price of a tower of the size
around 1 m2 is 6,000,000
(1)x
.
Obviously
the bigger towers cost less relative to size.
Other
elements to evaluate are: induced draft cooling towers with forced
ventilation; centrifugal fans, axial fans, built in galvanized steel,
stainless steel, polyester reinforced with glass fiber.
(We
should consider all tangible items that are now part of our
designer's skills).
In
the next article “Is a cooling tower a worthwile investment? (part
3)”, we shall see how to calculate the size of the tower with the
above available data.
(1)X is an hypothetical cost unit.
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