Radiation Between Two Gray Surfaces Attic

3 1 radiation between two gray surfaces consider the attic of a home located in a hot climate.

Radiation between two gray surfaces attic. Describe radiation exchange among surfaces in which the surfaces can be perfect absorbers of radiation black or diffusely absorbing gray. Radiation analysis of such enclosures becomes very complicated unless some simplifying assumptions are made. In this article we will discuss about the mechanism of heat exchange between two or more surfaces. Heat exchange between black bodies.

The floor of the attic is characterized by a width of l1 10 m while the roof makes an angle of 30 from the horizontal direction as shown in the schematic. Diffuse gray surfaces the analysis of radiation transfer in enclosures consisting of black surfaces is relatively easy as we have seen but most enclosures encountered in practice involve nonblack surfaces which allow multiple reflections to occur. Heat transfer between surfaces based on two assumptions. Consider heat exchange between elementary areas da 1 and da 2 of two black radiating bodies having areas a 1 and a 2 respectively.

The portion of radiation exchanged between two differently oriented surfaces has to be defined by a geometric function known as view factor which is developed for gray diffusely radiating surfaces. Surfaces form ideal closed enclosure and are separated by nonparcipating media. The house is 30 m long ls not shown into the page.