Environmental Engineering Reference
In-Depth Information
3.
Constructing Thermal Cascade Diagrams
This diagram is constructed using the total hot loads and cooling capacities obtained in
the previous step for each temperature intervals.[1,2,3]
The temperature intervals are drawn as “rectangular” with two inlets and two outlets.
The inlet from the left is the total hot load available in this interval (for instance, 1300
kW in case of interval # 2)
The inlet from above is the utility input load, in case of the
first
interval, or the input
from interval above in case of second, third,……,N intervals.
The output from the right is the total cooling capacity of this interval ( for instance, 1300
kW in case of interval #2).
The output from the bottom is the difference between the total inputs and the cooling
capacity of the interval
The heat balance around each interval will be conducted as above.
The reader is encouraged to do the calaculation for interval number 2 and see that in
interval number 2 the hot side input is equal to the cold side output and hence the final output
of the interval will be the same as interval number one ,-400 energy unit.
Upon the completion of the heat balance around each interval the following energy
deficiency diagram will be produced.
Thermal Cascade Diagram (Un-Balanced)
Note: During this step the input from Hot Utility to the first interval is equal to zero
0.0
0.0
400
1
-400
1300
1300
2
-
400
100
150
3
-
450
750
4
750
-
450
100
200
5
-
550
50
0
6
-500
Figure 11. Thermal Cascade Diagram (Un-Balanced)
