Design and construction of a solar-biomass energy system for grain drying.

Abstract

Maize is one of Uganda's foods Contributing about 35% of the daily dictary energy consumption. rates and about 80% of the rural households are involved in maize production. After harvesting, the greatest enemy of grain is moisture that has to be reduced by drying to increase grains’ shelf life. Solar drying of grains is commonly used in Uganda. Most used system of solar drying is the use of flat plate collectors which has drawbacks of requiring more space and having low concentration efficiency. Bad weather and inability to store sufficient solar energy reduces the effectiveness of drying that calls for integration of a biomass stove to enhance drying at night and during bad weather. This report therefore provides the methods far availing sufficient and cheap renewable energy that can be used by the famers to enhance profitability of agriculture by reducing the post-harvest losses. A solar-biomass energy system in this study was developed and achieved through the methodology, mainly studying the matrix air heater. In order to achieve the above purpose, data was collected which involved literature surveys and reviews and internet surfing, designing the system components, constructing the prototype which was tested and the results analysed. In this project, the matrix air heater gave temperature increments of 50C, 70C and the maximum was 10OC which was achieved by noon on a collector with a length of 0.6m and a width of 0.5m. In comparison with a flat plate collector of the same size, it's found to produce maximum temperature increments of 50C which therefore shows that a matrix air heater can be adopted in place of the flat plate collector. The further increase in temperature to a range of 40 to 45 0C as required for maize drying for Seed grain was attained by using a biomass stove which was lighted using firewood as the biomass fuel because it's locally readily available. However, testing the solar collector was not effective due to unfavourable weather conditions. Further work such as measuring the air temperature at the fan exit, increasing the collector size to that of an area of 1.286m2 and increasing visibility of energy in Operation Wealthy Creation, the country's poverty reduction strategy can be done to enhance the effectiveness and performance of the energy system.