IEA Solar Heating and Cooling Programm - NachhaltigWirtschaften.at

IEA SHC Task 38 Solar Air Conditioning and Refrigeration Subtask C2-A, November 9, 2009
Figure 23: Evolution of air and desiccant properties for the process section in function of the
wheel width and the angular position
We notice that for a given angular position the air humidity ratio decreases with the width of
the wheel and yields a temperature increase. The dehumidification increase significantly in
the first angular sector of the process (0-40°) and reaches its minimum and then increases
slightly with the angular position. This behavior of the humidity is due to the fact that after the
regeneration; the desiccant is dry and when reaching the process it starts to dehumidify and
then starts to saturate. The other reason is the heat of adsorption that heats the desiccant
which reduces its adsorption capacity.
While examining the air temperature and humidity ratio profiles we notice a certain angular
delay of the dehumidification in comparison with the temperature increase. This can be
explained that the desiccant coming from the regeneration is very hot and has a limited
adsorption capacity. So in the process sector; outside air must first cool the desiccant and
then dehumidification becomes effective.
The figures below show a similar behavior in the regeneration sector.
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