integration of solid oxide fuel cells and ... - Ea Energianalyse

5.5. Total optimization of system
eta | COP
Standard vs Optimized parameters
1,2
1,1
1,0
0,9
0,8
0,7
0,6
0,5
0,4
0,3
0,2
0,1
0,0
0,07
0,46
0,03
0,52 0,50
0,03
0,59 0,51
eta_HW
COP_ABS,fuel
eta_sys,el,net
0,55
Standard Optimized Optimized
ΔT_SOFC=120
Figure 5.32: All bars are for the Double stage with Air Preheat. The right and middle columns
are both for the optimized system, where i d has been optimized by aiming for a tradeoff factor
between cooling and electricity of 3,4.
With the new ∆T min = 11 ◦ C for the additional air preheat (GGHEX4),
the total gain of using air preheat is 14kW (59kW with air preheat vs
45 kW for the same parameters without air preheat (not shown in the
figure)).
5.5.3 Future: ∆T SOFC = 120 ◦ C
It is now investigated what will happen if it in the future becomes
possible to use a 120 ◦ C temperature span over the fuel cell (i.e. inlet
temperature is kept constant while outlet temperature is increased from
780 ◦ C to 810 ◦ C).
As seen in figure 5.32 the electricity generation increases 5kW while
the cooling power decreases 8kW 14 . From a cooling perspective this
14 the current density has been adjusted to give the same tradeoff factor between
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