This study examines the heat and mass transfer coefficient, thermal effusivity, and other thermal properties of solar-dried cocoyam chips, as well as the drying kinetics. The research also assessed the economics of the solar dryer. For these reasons, a solar dryer with a partitioned collector was developed that creates a double airflow travel distance to delay the airflow inside the collector. The partitioning of the collector delays the airflow and helps to create more turbulence for the airflow with increased energy. The solar dryer was locally developed at the Michael Okpara University of Agriculture and tested during the humid crop harvesting period of September for the worst-case scenario. The obtained drying curves and kinetics for cocoyam drying are subjected to the vagaries of weather conditions. The drying rate showed declining sinusoidal characteristics and took about 25 h to attain equilibrium. Analysis of the airflow velocity showed gravitation between laminar and turbulent flow, ranging from 171.69 to 5152.77. Specific heat capacity, thermal conductivity, and effusivity declined with moisture content while the thermal diffusivity increased. However, the values of thermal effusivity ranged from 12.2 to 47.94 W.s1/2.m−2.K−1, which is within the range of values for insulators. The heat and mass transfer coefficient varied as a function of the airflow velocity. Fitting the drying curve into semi-empirical models showed that the two-term model was the best-fitted model for the experimental data from drying cocoyam. Using the solar dryer in Nigeria can save $188.63–$1886.13 in running costs with a payback period of 0.059–0.59 years (21.54–215.35 days) at a rate of 10–100% of usage.

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This research aims to establish the interconnectivity between mix-mode solar dryer designs with carbon and energy cost mitigation using different energy scenarios and study the drying kinetics to obtain the optimal drying rates for drying blanched potato s dryer fabricators and also assist them in making the right choice for carbon emission management for environmental sustainability and determining the end point of drying potato slices for energy conservation. Hence a mix mode solar dryer was deployed with sun-drying using blanched potato as a case study. The potato slices were spread on the drying tray to form a thin layer. Mass loss data and Temperature and relative humidity data were recorded at 1 h intervals until the desired moisture content was achieved. The dryer utilized 4.562 M J to dry the potato slices from 64 % w.b initial moisture content to 7.56 % w.b final moisture content. The percentage of the energy utilization ratio (EUR) ranged from 4.19 to 82.68 % with an average value of 39.46% while the thermal efficiency of the solar dry varied from 0.6 % to 34 % with an average value of 17 %. The dryer can save from$74.22 to $741.22 per year at a 10 to 100% rate of usage with an indicative payback period of 0.17 1.64 years at the same rate of usage. The decarbonisation potential of the solar dryer was high when compared to coal, diesel or grid electricity-powered dryers as an energy case scenario with the values ranging from 2.9 -237.71tones of CO2 per year with earned carbon credit ranging from $41.98 to $ 3446.85 per year. Blanching time affected the drying rate and effective moisture diffusivity of the potato slices with effective moisture diffusivity varying from 6.35 × 10 11 to 7.07 × 10 10 m 2 /s for sun-dried potato slices and 9.86 × 10 11 to 1.24 × 10 9 m 2 /s for solar drying potato slices. Using the solar dryer reduced the drying time by 25.81 to 34.48 % compared to open sun drying. The optimum drying rate for the solardried untreated potato slices was 0.0239665 kg/h at a collector temperature of 40.93 o C and thermal efficiency of 17.30 % while blanching for 3 minutes, 6 minutes and 9 minutes gave optimum drying rate of 0.0177959kg/h, collector temperature (T) of 40.9 o -treatments.

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