Theoretical and experimental assessment of a double exposure solar cooker Emad H. Amer * Department of Mechanical Power Engineering, Faculty of Engineering, Menoufiya University, Shebin El-Kom, Egypt Received 2 August 2002; accepted 26 December 2002 Abstract A novel design of solar cooker is introduced in which the absorber is exposed to solar radiation from the top and the bottom sides. A set of plane diffuse reflectors is used to direct the radiation onto the lower side of the absorber plate. The performance of the new cooker and the conventional box type solar cooker is extensively investigated. The general energy balance of the cooker is derived and is used to predict the temperature variation of each part of the cooker under both steady and transient conditions. The predicted values are compared with measurements made under actual weather conditions. Results under the same operating conditions show that the absorbers of the box type cooker and the double exposure cooker attain 140 and 165 °C, respectively. The temperatures of the air inside the two cookers are 132 and 155 °C, res- pectively. The predicted temperatures agree with measurements under transient conditions within 1.2 °C for the absorber plate, 1.8 °C for the oven air and within 2.5 °C for the glass cover. The time taken for cooking of several foods and for boiling the same amount of water is obtained for the two cookers under the same conditions and at the same location. The double exposure cooker reduces the cooking time by about 30–60 min. The taste and appearance of the food is quite good. Ó 2003 Published by Elsevier Science Ltd. Keywords: Solar energy; Box cookers; Temperature variation; Cooking time 1. Introduction Solar energy can make a major contribution to the energy needs for cooking food. This is particularly true for remote and rural areas where solar radiation is available at a large scale and there is a lack of other energy forms. Even when other sources of energy are available, Energy Conversion and Management 44 (2003) 2651–2663 www.elsevier.com/locate/enconman * Tel.: +20-48-221549; fax: +20-48-235695. E-mail address: amer_h_emad@yahoo.com (E.H. Amer). 0196-8904/03/$ - see front matter Ó 2003 Published by Elsevier Science Ltd. doi:10.1016/S0196-8904(03)00022-0