Energy and exergy analyses of solar drying system of red seaweed

A solar drying system was designed, constructed and tested for drying of seaweed. Seaweed is a potential source of renewable energy, and it can be converted into energy such as biofuel oil, biodiesel and gas. Red seaweed was dried to the final moisture content of 10% from 90% w.b in 15 h. Drying kinetics of red seaweed were investigated and obtained. The nonlinear regression procedure was used to fit three different drying models. The Page's model clearly showed a better fit to the experimental data between Newton's model and Henderson and Pabis model. The Page's model was resulted in the highest value of R2 and lowest values of MBE and RMSE. At average solar radiation of about 500 W/m2 and air flow rate 0.05 kg/s, the collector, drying system and pick-up efficiencies were found about 35, 27 and 95%, respectively. This study was performed with energy analysis and exergy analyses of the solar drying process of red seaweed. The specific energy consumption (SEC) of 2.62 kWh/kg was obtained. Moreover, the exergy efficiency of solar drying ranged from 1% to 93%, with an average of 30%. The values of improvement potential were found to be in the range of 0.3 and 630 W, with an average of 247 W.