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The groundnuts were dried inside an even span roof type free convection greenhouse dryer with a useful floor area of 1.2x0.8m² in the environmental conditions of Rohtak, India (28° 54'-N 76° 34'E). Wire mesh sieves of sizes 0.15x0.25 m², 0.25x0.4 m², and 0.35x0.6 m² were used to accommodate thin layer samples of groundnuts. The groundnuts were dried till the optimum safe moisture storage level (8%-10%) was attained. Based on experimental (hourly) observations the values of constants (C and n) in the equation of Nusselt number were evaluated. The values of convective and evaporative heat transfer coefficients were calculated which were observed to decrease with the increase in the sieve size. The overall average greenhouse thermal, energy, and exergy efficiencies were evaluated as 8.83%, 22.67%, and 2.75% respectively. The overall average experimental error in terms of % uncertainty for groundnuts drying was evaluated as 37.94%. [ABSTRACT FROM AUTHOR]

The thin layer drying behaviour of groundnut was investigated under open sun drying (OSD) and indoor forced convection drying (IFCD) modes. The groundnut samples were dried from initial moisture content of 38% (w.b.) to the safe storage moisture content of 8%-10% (w.b.). Four mathematical models were compared for describing the groundnut drying process. The performance of thin layer drying models was investigated by comparing the statistical parameters such as coefficient of correlation (R), reduced chi-square (Χ²), root mean square error (RMSE), and mean bias error (MBE) between experimental and predicted moisture ratios. Henderson and Pabis model was observed to give the highest value of R and lowest values of Χ², RMSE and MBE for the groundnut drying under both OSD and IFCD modes. The values of statistical parameters under Lewis model were also found to be very close to Henderson and Pabis model. Therefore, Henderson and Pabis and Lewis models were found to be the best for describing the drying behaviour of groundnut under both given conditions. [ABSTRACT FROM AUTHOR]

In this paper, convective and evaporative heat transfer coefficients of the Indian groundnut were computed under indoor forced convection drying (IFCD) mode. The groundnuts were dried as a single thin layer with the help of a laboratory dryer till the optimum safe moisture storage level of 8 - 10%. The experimental data were used to determine the values of experimental constants C and n in the Nusselt number expression by a simple linear regression analysis and consequently, the convective heat transfer coefficient (CHTC) was determined. The values of CHTC were used to calculate the evaporative heat transfer coefficient (EHTC). The average values of CHTC and EHTC were found to be 2.48 W/m2 oC and 35.08 W/m2 oC, respectively. The experimental error in terms of percent uncertainty was also estimated. The experimental error in terms of percent uncertainty was found to be 42.55%. The error bars for convective and evaporative heat transfer coefficients are also shown for the groundnut drying under IFCD condition. [ABSTRACT FROM AUTHOR]

Peanut or groundnut is one of the major oilseed crops in the world. It is rich in oil and proteins. Developing countries account for about 95% of the world peanut production. Asia alone accounts for 70% of this amount where the major producers India and China together represent over two-third of global output. Traditionally, groundnuts are dried in open sun to its safe moisture level for storage. Natural and artificial (hot air drying) drying methods of groundnuts are being used throughout the world. Artificial peanuts drying devices consume very large amount of energy. In this paper, present status of peanut and a comprehensive review of its drying methods are discussed. Recent developments in preservation and storage of groundnuts are also highlighted. [ABSTRACT FROM AUTHOR]