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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]

Limited sources and rising cost of fossil fuels has instigated researchers to look towards renewable energy resources. Among renewable energy resources, solar energy is required to become indispensable in the future, as it is inexpensive, abundant, inexhaustible, environmental friendly and non-pollutant. Most of the people living in developing countries are dependent on agriculture. Agricultural products are dried to increase the storage life, minimize the packaging requirement and reduce the transportation weight. Solar drying for drying agricultural products is being practiced since long back throughout the world. Because of its drawbacks, advance technique, i.e. greenhouse drying, is being adopted for drying crops to reduce the drying time and increase the quality of the food products. Some new methods have also been attempted to increase the drying efficiency of greenhouse. In this paper, a comprehensive review of greenhouse drying of various commodities is presented. Different parameters such as thermal analysis, drying characteristics of crops, energy and exergy analysis, and greenhouse drying performance were discussed. In addition, the economical aspects of greenhouse dryers were also highlighted. This review paper will be helpful to the new researchers to know about the various technical aspects of the greenhouse dryer. [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]