Solar Drying: Fundamentals,Applications and Innovations - National ...

Fadhel - Recent Advancements in Solar Drying
banana. To investigate the experimental performances of the solar greenhouse dryer for
drying of peeled longan and banana, 10 full scale experimental runs were conducted. Of
which five experimental runs were conducted for drying of peeled longan and another
five experimental runs were conducted for drying of banana. The drying air temperature
varied from 31 ⁰ C to 58 ⁰C during drying of peeled longan while it varied from 30 ⁰C to 60
⁰C during drying of banana. The drying time of peeled longan in the solar greenhouse
dryer was 3 days, whereas 5–6 days are required for natural sun drying under similar
conditions. The drying time of banana in the solar greenhouse dryer was 4 days, while it
took 5–6 days for natural sun drying under similar conditions. The quality of solar dried
products in terms of color and taste was high-quality dried products. A system of partial
differential equations describing heat and moisture transfer during drying of peeled
longan and banana in the solar greenhouse dryer was developed and this system of nonlinear
partial differential equations was solved numerically using the finite difference
method. The numerical solution was programmed in Compaq Visual FORTRAN version
6.5. The simulated results reasonably agreed with the experimental data for solar drying
of peeled longan and banana. This model can be used to provide the design data and is
also essential for optimal design of the dryer Janjai et al. (2009).
Figure 6.15. The greenhouse solar dryer. (Janjai et al. 2007)
6.3.8 Photovoltaic/Thermal solar collector (PV/T) drying system
One of the ingenious methods of solar energy conversion systems is the photovoltaic
thermal air collector or hybrid solar collector, which converts solar radiation to both
thermal and electrical energies for use in drying systems. The integrated arrangement
for utilizing thermal energy, as well as electrical energy, with a PV module is referred to
as hybrid PV/T system (Chantana et al. 2009). The hybrid PV/T system can be used for
air heating and water heating.
Chantana et al. (2009) presented the conceptual design of the Hybrid PV/T assisted
desiccant integrated hot air combined with an IR drying system (HPIRD) (Figure 6.16).
142 Drying of Foods, Vegetables and Fruits