Performance Evaluation of a Double-Glazed Box-Type Solar Oven with Reflector

This research paper describes the performance evaluation of a double-glazed box-type solar oven with reflector fabricated using locally available materials, compressed sawdust with binder; size of the box is 700？mm？×？ 700？mm × 400？mm and 10？mm thickness. The experimental solar cooker consists of an aluminium absorber plate (1？mm) painted matt black and a double-glazed lid. The bottom and sides are lagged with fibreglass wool insulator, thickness = 50？mm, ？W/m°C. The reflector consists of a wooden-framed commercially available specular plane mirror which is sized to form a cover for the box when not being in use. Its thermal performance was tested according to the ASAE International Test procedure and Bureau of Indian Standards (BIS) for testing the thermal performance of box-type solar cooker. Thermal performance experiments were conducted in order to determine the first figure of merit (F1), the second figure of merit (F2) and standard cooking power (Ps). The obtained test results were employed to calculate the two figures of merit (F1, and F2) and the standard cooking power (P50) to be 0.11？Km2w？1, 0.31, and 23.95？W, respectively. Finally, the results illustrated that the cooker has a good reliability for cooking food and boiling water. 1. Introduction From time immemorial, fire has been used for cooking food to make it palatable and digestible. In ancient times, in the villages, there was no scarcity of fuel, and hence, not much attention was given to minimize the loss of energy while using wood for cooking. Almost invariably, open fire was used for transferring the heat energy to the food from the source of the fuel and this accounted for a large percentage of heat lost to the surroundings. Unfortunately, up to the present day, where gas cooker or electric stove is used, the problem of heat loss to the surrounding still exists. It is for this reason that very high amount of fuel is needed for cooking, so that enough heat is available for cooking of food inspite of considerable loss of heat from the source of fuel: wood, coal, gas, or electricity. The main sources of power generation today are fossil fuels (oil, gas, and coal), nuclear reaction, and hydro energy is also used. These are depletable, nonrenewable and pollute the environment. The hydro energy does not produce adequate and consistent power for the nation’s consumption [1]. Moreover, the high cost of exploration techniques and the devaluation of the currency of a developing country like Nigeria have made the power from fossil fuel unaffordable for most people [2]. Two million households