The coupled conductive radiative heat transfer is investigated within a semi-transparent medium. The two dimensional case of a parallelogram is considered. The specificity of the approach proposed here consists in expressing the divergence term of the radiative heat flux that appears from the temperature. In that way, it remains only one differential equation to solve numerically. Compared to classical approaches, the equation is certainly more complicated but the method is more efficient because the problem becomes uncoupled. Results are presented for different parallelograms more or less flattened.