In this study, we have first conducted a comparative study between open sun drying understood as open sun and indoor the designed solar greenhouse dryer, in order to determine the difference between both environmental conditions. The solar greenhouse dryer can achieve 25.20 C higher temperature and 20% less relative humidity than open sun drying for the experimentally tested in the south of Spain. Thus, it was demonstrated that the environmental conditions generated inside the solar greenhouse dryer are more favourable for a wood chips drying in less time and also suitable for reaching final moisture content less than what can be achieved in drying outdoors for the same place and time of year. The models of piles tested show best results for the extended or cordoned against conically shaped for the same volume. The wood chips can be dried, 10% of relative humidity achieved in 13 days in normal conditions, with an average solar radiation of 13.74 MJ/m2 (autumn season). It could be concluded that, the use of the solar greenhouse dryer allows improving the wood chips as biofuel by
reducing the relative humidity in a shortest period of time when it
is compared to open sun drying.