This work is denominated Numerical resolution of heat and mass transfer phenomena. Application to the analysis of heat loss by convection in a flat solar collector. It is divided into eight chapters and four annexes. Chapter 1 presents the objectives, scope, and exclusions of the work. Chapter 2 is dedicated to the analysis of heat conduction in solids, while Chapter 3 covers the various methodologies of resolution of the Convection-Diffusion Equation. An introduction to the numerical resolution of the Navier Stokes equations is presented in Chapter 5. The experimental work on the flat solar collector and its results are presented in Chapter 6. The final conclusions are presented in Chapter 7 and the bibliography that was used for the development of this paper is presented in Chapter 8. In addition, three annexes are presented, Annexes A, B, and C which present the computational codes developed. Annex D presents the daily reports of the experimental part for the selected days.