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

4.9. Validation of Model
4.9 Validation of Model
During the development of the model, the output (results) has been
compared to other models as well as measured data. Rules of thumb
have also been taken into account. In some cases additional variables
have been introduced in order to validate the model and will be
described in the following.
4.9.1 SOFC
In the standard parameter configuration the increase of the temperature
from the inlet to the outlet of the fuel cell (∆T SOFC ) is 90 ◦ C. The fuel
utilization factor U f is 0,7 and the current density isi d = 3000 A . The
m 2
fraction of reforming in the pre reformer (F R) is 0,14. The air utilization
factor (U air ) which is dependent on ∆T SOFC , U f and F R is calculated to
0,16 which is quite close to that of the TOFC models [25].
Recycling
The fraction of anode recycling α SPG1 is 0,62. This deviates less than
5% from an equivalent SOFC system modeled by TOFC. And the gas
composition at the SOFC anode outlet matches the TOFC model.
Blower power
A rule of thumb says that the blower consumes 10% of the produced
power [25]. Ẇ Blower is 5,5kW which corresponds to 10% of Ẇ SOFC ,SOLO
(see definition in equation 4.6 and 4.7 page 98), while the TOFC models
the fraction is in the range of only 5-8% of the net power.
Since the SOFC system in this project is integrated with an absorption
cooling unit, more heat exchangers are applied and hence it is expected
that the total pressure loss of the exhaust gases must be higher. Taking
this into account the blower power consumption seems to be reasonable.
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