UNIVERSITÉ PAUL CÉZANNE, AIX MARSEILLE III - IMEP

Résultats et discussion. Chapitre 5: Disponibilité des substrats oléicoles
heat gain in the greenhouse was 10% higher than the outside. In accordance with the
increased temperature and heat gain, the drying of the OC-OMW mixture was much faster in
the greenhouse than outside (Fig. 4).
Moisture content (%)
Figure 4. Typical drying curve of the OC-OMW mixture in the greenhouse ( ) and open sun
( ) in Rabat-Morocco during February 2008; (a) First drying; (b) second drying.
For the first drying, height hours of the day time were sufficient to reach the target
moisture (40% w/w) in the greenhouse compared to 12 hours outside, which means that the
drying process was some 1.5 times quicker in the greenhouse. For the second drying, the
products obtained after 35 hours of drying including a night during which a very low loss of
moisture occurred (less than 5% w/w in 10 hours) were also 3 times dryer in the greenhouse
than outside (10% moisture against 30% w/w). The main limiting factor in the drying process
corresponds to the very low drying efficiency achieved during the night period. This
efficiency could be improved by implementing forced convection through the use of a fan
powered with batteries recharged in the day by means of solar cell modules installed on the
top of the greenhouse (Chow, 2009). Further, it is possible to imagine a complete automation
of the absorption drying-process. OC may be loaded in the greenhouse with Archimedes
screws and humidified with OMW through a dispositive of showers which could allow
controlling precisely the humidity of the mixture.
a
Time (h)
b
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