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Hydrogen Applications
Forced-draft AFC
Air-water co-current flow in Tundracel
the cooling water can be cooled down to 25 ° C . An approach of 2 ° C must be added for the closed loop as a plate and frame heat exchanger is used to transfer heat from the closed loop to the open cooling tower . The closed loop is cooled down to 27 ° C . However , another
2 ° C must be added for the plate and frame exchanger in the process . This results in a minimum achievable process temperature of 29 ° C .
Fogging system The highest ambient temperatures normally occur only over a relatively short period of time each year ( except for tropical regions ). Nevertheless , this design point determines the overall size of the AFC . And this results in an installation that is oversized most of the time . A clever solution to this problem is the use of a fogging system . Hundreds of small nozzles are installed below the AFC tube bundle . Very pure water ( demineralisedwater quality or at least soft water with inlet pressure between 3 and 5 bars ) is atomised and sprayed into the air stream , evaporating before it enters the tube bundle . While the water evaporates , it cools down the air before entering the tube bundle . This principle is called adiabatic cooling . By using a fogging system , the inlet air temperature can be reduced by as much as 10 ° C ! Such a reduction in design ambient air temperature has a dramatic impact on the
Installation
Air Fin Cooler ( AFC ) AFC with spray system AFC with adiabatic pads Cooling tower
12 bays , 2 bundles per bay , tube length 15 m
6 bays , 2 bundles per bay , tube length 15 m
6 bays , 2 bundles per bay tube length 15 m
4 cells 8.7 m x 8.7 m
Min . achievable process temp . |
39 ° C |
39 ° C |
39 ° C |
29 ° C |
Number of fans |
36 |
18 |
18 |
4 |
Total plot space |
80 x 15 m ( 1200 m 2 ) |
40 x 15 m ( 600 m 2 ) |
40 x 15 m ( 600 m 2 ) |
8.7 m x 37.8 m ( 329 m 2 ) |
Installed motor power |
1,330 kW |
666 kW |
900 kW |
300 kW |
Annual electrical consumption |
100 % |
50 % |
70 % |
25 % |
Annual Evaporated water amount |
N / A |
6,395 m 3
|
6,395 m 3
|
385,440 m 3
|
Annual Water usage * |
N / A |
6,395 m 3
|
8,527 m 3
|
514,212 m 3
|
CAPEX factor |
100 % |
65 % |
85 % |
25 % |
* Based on a cycle of concentration ( CoC ) of 4 , which depends on make-up water quality |
Electrolyser capacity : 100 MW |
Design capacity of the central cooling system : 32 MW |
Dry / Wet-bulb temperature : 30 ° C / 21 ° C |
Switch-on temperature of the spray system : 23 ° C |
Table 1 : Technology comparison ( fixed process temperature )
24 Heat Exchanger World November 2022 www . heat-exchanger-world . com