Development and Performance Evaluation of a Mobile Solar Dryer for Cassava Chips

Abstract

In this study, a mobile, indirect passive solar drying system was designed and constructed on the principles of convective heat flow using locally sourced materials to dry cassava chips. The performance of the dryer was evaluated and the results obtained showed that the system is to a large extent effective in dehydrating food items reasonably and rapidly to a save moisture level. The maximum temperatures obtained in the collector, lower and upper parts of the drying chamber were 78.5, 71.0 and 68.5 o C, respectively during the validation test at noload operating condition, while maximum temperature of 71.0, 62.5 and 60.0 o C, respectively were obtained during the dehydration test. The maximum ambient air temperature was 33.5 o C. The dryer was able to reduce the moisture content of 500 g cassava chips from 74.5 to 20.3% (dry basis) in 6 hours of effective dehydration time. The system overall thermal efficiency and average drying rate were found to be 58.4% and 0.083 kg/h, respectively.

Development of Hot-Air Supplemented Solar Dryer for White Yam (Dioscorea Rotundata) Slices

“…4 and the lowest was 33.3 °C at solar radiation intensity of 300.408 W/m 2 . The efficiency of the solar collector depends on the air flow rate and the difference in temperature and radiation intensity was obtained at the highest efficiency of the solar collector giving an efficiency of 83.28 % at solar radiation intensity of 1199.46 W/m 2 and the lowest efficiency of the solar collector was 23.89 % at solar radiation intensity of 300.408 W/m 2 which gives a better solar collector efficiency result compared to that that of [21], [19] and [22].…”

“…For this research work, the thermal performance of solar dryer can be defined as the thermal energy utilized for drying over the thermal energy available for drying [19]. But according to [20], [21], and [22], the overall efficiency of solar dryer was simplified based on the equations below: The thermal energy available for drying through the solar collector (Q c ) is given as: [19] C pf = specific heat capacity of dried food at constant pressure (J/kg.K) (ii) Sensible heat used to raise temperature of the water in the food (Q sw ); [22] (17) Where, m w = mass of water content (kg); and, C pw = specific heat capacity of water at constant pressure (J/kg.K). (iii) Latent heat used to vaporize the water in the food (Q lw ); [22] (18) Where, m v = mass of water vapour (kg); and L v = latent heat of vaporization (J/kg).…”

“…But according to [20], [21], and [22], the overall efficiency of solar dryer was simplified based on the equations below: The thermal energy available for drying through the solar collector (Q c ) is given as: [19] C pf = specific heat capacity of dried food at constant pressure (J/kg.K) (ii) Sensible heat used to raise temperature of the water in the food (Q sw ); [22] (17) Where, m w = mass of water content (kg); and, C pw = specific heat capacity of water at constant pressure (J/kg.K). (iii) Latent heat used to vaporize the water in the food (Q lw ); [22] (18) Where, m v = mass of water vapour (kg); and L v = latent heat of vaporization (J/kg). Therefore, [22] (19) Or [19] (20) The thermal efficiency of solar dryer (η d ) is the ratio of the thermal energy utilized for drying (Q u ) over the thermal energy available for drying through the solar collector (Q c ).…”

“…(iii) Latent heat used to vaporize the water in the food (Q lw ); [22] (18) Where, m v = mass of water vapour (kg); and L v = latent heat of vaporization (J/kg). Therefore, [22] (19) Or [19] (20) The thermal efficiency of solar dryer (η d ) is the ratio of the thermal energy utilized for drying (Q u ) over the thermal energy available for drying through the solar collector (Q c ). [22] (21)…”

“…Therefore, [22] (19) Or [19] (20) The thermal efficiency of solar dryer (η d ) is the ratio of the thermal energy utilized for drying (Q u ) over the thermal energy available for drying through the solar collector (Q c ). [22] (21)…”