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

5.3. Partial optimization of standard parameters
this it can be concluded that an absorption cooling unit should preferably
be used to cool down things to low temperatures where electrical
units loose a bigger fraction of their COP - it is not good for just cooling
things a few degrees. But since the refrigerant is water, it is impossible to
get much lower than 5 ◦ C for a water-LiBr absorption unit (otherwise the
water freezes), so there is a quite sharp lower limit.
Relative humidity
The influence of the relative air humidity is now examined. The ambient
temperature is kept at 30 ◦ C:
Figure 5.10: A): The COP and efficiencies are shown together with the water consumption of
the cooling tower. B (right side): The green curves show the temperature of the air in and out of
the cooling tower. The blue curves show the temperature of the water in and out of the tower.
As can be seen from the dark blue curve in figure 5.10B, the model
of the cooling tower predicts a decrease of the water outlet temperature
when the relative humidity is decreased. This is because the wet bulb
temperature is reduced.
Figure 5.10A shows that from a COP perspective, it is most beneficial
if the ambient air is as dry as possible since the water can thereby
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