Comparison of Different Sources of Energy Used for Crop Drying

Drying is an energy intensive operation and is one of the major operation costs in a drying unit. Agricultural crop drying has been reported to account for 12 to 20% of the energy consumption in the agricultural sector. (Liviu and Badea, 2009). Industrial diesel oil (IDO), a blend of diesel and heavy fuel oil is the main source of thermal energy for power generation and steam/water boilers in small agro-industrial applications in Kenya. Heavy fuel oil (HFO), which is a residual of crude oil refinery, is used mainly by power generators, boilers and furnaces in big industrial applications (Kiruja, 2017). Other energy sources commonly used in crop drying are wood fuel and Sun drying. Geothermal rich areas can harness the energy and use it for various applications such as crop drying. The technology is quite simple and entails the use of basic engineering techniques with minor modifications to suit the specific application. A key component is the heat exchanger unit where usually cold water extracts heat energy from hot geothermal fluids. The resulting hot water or steam will be used for crop drying. A comparison of different sources of energy that are used to generate thermal energy for agro-industrial application is essential so as to adopt the best options available while considering, economic and environmental benefits among other factors. For ease of comparison, equivalent cost of each source fuel in US$/kWh will be calculated. The analysis also aims at informing the energy sector players who are involved in developing energy policies.