Air heating flat-plat solar collectors are usually rectangular
passages with two openings at both of their ends, inlet and
outlet. The main engineering concept behind the air heating
solar collector is natural convection. The most common
applications of air heating solar collectors are the domestic
heating, solar dryer, solar chimney and Trombe Wall.
The evaluation of the outlet temperature of flow in passages
with rectangular cross section is still of interest for the
convective heat transfer investigators. Many parameters are
involved in such case, for example the passage length, gap
size, inclination angle, walls temperature, ambient conditions
like temperature and humidity,