Numerical simulation of an air solar collector operating on natural convection regime

In this paper the numerical simulation (using the code Fluent 6.3) of an air solar heater operating on natural convection regime was carried out. The aim was to determine the behavior of velocity and temperature profiles in the heater. The results show that the air temperature increases quasi-linearly with the longitudinal coordinate, independent of the length of the heater. The temperature of the absorber has an abrupt step at entrance and then grows approximately as an exponential. The behavior of the air and plate temperatures is independent of the incident radiation. The air temperature profile maintains its shape along the collector and shows that the temperature drops sharply as it moves away from absorber. The velocity profile starts practically flat at entrance and sets its definitive shape at coordinate close to 40 % of the collector length. The maximum velocity of air is located 0,2 channel height taken from the plate. (author)