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

5. SIMULATION AND RESULTS
Figure 5.8: Efficiencies and COP for Double Stage system with standard parameter
configuration. A: Dry Tower. The grey area is where the system is not able to run. B: Wet
Tower
So there is very little idea in using the absorption cooling unit in
conjunction with a dry tower - the ambient temperature has to be so low
for this to work, that the cooling service could probably just as well be
provided by blowing the ambient air over the product which needed the
cooling service. Furthermore air conditioning is rarely needed when the
ambient temperature is below 20 ◦ C, so a dry tower does not seem to be
usable for the double stage ABS unit 4
When the wet tower it used, the cooling COP increases somewhat
when the ambient temperature is decreased (see blue curve in figure
5.8B), but not at all as much as would have been the case for an electrical
air conditioner. But in very hot climates, the limit at around 38-40 ◦ C
could be a problem. It might be rare for so high a temperature to occur,
but when it does, air conditioning would be absolutely crucial.
Further investigations, however, show that if the temperature of
the high pressure desorber is increased, the condenser and absorber
temperature can be increased, whereby the system will be able to operate
4 A single stage ABS unit would be better as using a dry tower since the desorber
temperature of this is normally around 80 ◦ C, so it could be raised without any problem -
thereby making it possible to use a higher absorber and condenser temperature as well.
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