DESIGN, CONSTRUCTION AND PERFORMANCE EVALUATION OF A SOLAR BOX COOKER

Abstract

The design, details of construction and performance analysis of box - type solar energy cooker are presented. The cooker consists of outer casing, absorber plate (cooking chamber), double-glazing coverlid, booster reflectors, which increases the magnitude of absorber temperature, i.e. enhances solar radiation and reduces heat losses. The cooker is made of a 0.001m thick aluminium tray in form of an inverted truncated square-based pyramid. Its base is 0.7m x 0.4m and the slanting height is 0.18m. The top consists of an aluminium framed double – glazed lid with a transparent surface area of 0.8m x 0.5m. The three insolation boosters consist of angle iron-framed, commercially available plane mirror, the bigger booster serves as cover for the box when not in use. The cooker can contain three cooking vessels each capable of holding 6 kg of water conveniently. Thermal performance tests of the cooker were undertaken under no load condition to determine the stagnation absorber plate and ambient air temperature. The workability of the cooker was determined. Sensible heat tests were carried out to determine the time required to boil given quantities of water and the cooking times of various food items. Maximum temperature of 141°C was recorded during the test period for the absorber plate. The thermal efficiency of water heating, efficiency of solar cooker, and energy efficiency of the cooker were 48.26, 44.85% and 41.37% respectively, this is greatly influenced by the direct radiative intensity, ambient temperature and wind speed.