Numerical methods and simulations in fluid dynamics and Heat Transfer (HT) are constantly growing in terms of number of both courses offered at universities and active researches in the field. Nowadays, Computational Fluid Dynamics (CFD) codes are being consolidated as design tools by the industry and both commercial and open-source codes are available. Anyway, users of CFD need to have a fully understanding of the numerical methods implemented in these more complex software in order to give meaning and accuracy to their results. Therefore, the two main objectives of this project are: firstly, to acquire a basic training in the numerical resolution of the governing equations in heat transfer and fluid dynamics problems, acquiring the skills to critically judge their quality through validation techniques and, secondly, apply the developed knowledge to a real-world case like the heat transfer study of a flat-plate solar collector.