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

5. SIMULATION AND RESULTS
Figure 5.12: A: Efficiencies and COP. B: The red and purple curves show the temperature before
and after heat supply to the absorption unit. The brown curve shows how much heat the high
temperature desorber receives, and the green curve shows how much heat DES1 receives (from
COND2).
Desorber 1
The temperature of the low pressure desorber (DES1) is somewhat
restricted by the temperature of the high pressure desorber (DES2).
When T DES2 =150 ◦ C, T DES1 must be between 68 ◦ C and 88 ◦ C for the system
to operate. From figure 5.13A it can be seen that the optimum of the blue
COP curve is rather flat though, so the exact temperature is not so critical
for the performance.
In the standard configuration, the temperature of DES1 is not given
explicitly since the system will not be able to run if e.g. T DES2 is altered
too much while T DES1 remains constant. Instead the ratio of the mass
flow rate of the refrigerant out of the desorber and the mass flow rate of
solution into the desorber is set equal for the two desorbers:
ṁ 50
ṁ 58
= ṁ70
ṁ 78
(5.1)
This is the same as saying that the difference between the strong
and weak LiBr-solution is the same for two desorbers. And figure
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