Development and Performance Evaluation of a Box-Type Solar Cooker

Abstract

The attributes of size optimization and good heat storage capability coupled with the efficient performance have made box type solar cooker a preferable cooker among its peers. This research work developed and evaluated the performance of the box-type solar cooker. It comprises a rectangular box with the inner walls forming the cooking chamber made into the shape of an inverted, truncated square-based pyramid. Insulating glass wool is used to fill the gap between the internal and external walls. The cooker collector surface consists of a double glazed lid, which is rigidly framed and hinged to one side of the box. A framed reflector is also incorporated to boost the isolation and cover the glazing when the cooker is not functioning. The reflector, when in use, is always oriented towards the sun. The cooking chamber is actually formed by aluminum tray with slanting sides, and the base is painted matte black and adapted as the absorber. Flexible tube is passed through the side walls to the exterior to release steam into the surrounding. Access to the cooking chamber is by lifting the jointed glass lid. Sensible and no-load tests were conducted at different atmospheric temperatures. The ambient temperatures recorded for four consecutive days were: 303, 304.5, 302 and 306K. The increase in temperature of the cooker was recorded at 20 minutes interval. The maximum absorber temperatures during no-load test at the atmospheric temperatures recorded were: 378, 380, 374 and 383K respectively. The cooker was also used to boil 450 ml of water and 250 g of rice. It was observed that it took about 38 minutes for the rice to be cooked during sensible test. The efficiency of the cooker was also found to be 72.21%.