Performance Modeling and Parametric Analysis of a Double Glazed Solar Oven

Abstract

Abstract-This paper investigates the thermal performance of a unique box type solar oven whose five sides are exposed to ambient and provisions are also provided to install the reflectors to enhance the intensity of incident solar radiation on the oven. Experiments were performed where temperatures attained inside the box cavity are recorded on different days and times of the day corresponding to various intensities of available solar radiation. A steady sate heat transfer numerical model of the solar oven without reflectors is also developed based on six individual thermal resistance networks which account for the heat losses through each flat-side of the oven box and a good agreement with the experimental data is achieved. A parametric study based on numerical calculations and experiments is then carried out to study the effects of various parameters on oven's thermal performance, e.g. number of glazings, distance between glazings and box, type of absorber coating, etc. Higher box temperature is attained using double glazing than single glazing. As compared to black paint, selective surface coating results in significantly higher oven temperatures (up to 40 o C). Plate spacing of 20-30 mm is found to be optimum distance between oven box and glass covers.Index Terms-Solar oven, oven box temperature, reflectors, overall heat transfer coefficient.

A magnetically-activated thermal switch without moving parts

“…Nanofluids [29], made of high thermal conductivity nanoparticles suspended in a fluid, display enhanced thermal properties and are more effective in heat removal. In particular, magnetic nanofluids, besides offering enhanced thermal conductivities, can be externally redirected to specific areas on demand by just applying small magnetic fields [2,27]. Thus, they can be moved into localized hot spots where they can absorb heat that is then released at a far away location after the field is removed.…”

“…Fluids remove this problem altogether: by adapting to the contact surface, the interface resistance is decreased. Thus, fluidic thermal switches have been widely reported in the literature [23,24,25,26,27]. Liquid metal coolants have been used taken advantage of the electrowetting effect [28].…”