Two different experimental devices have been tested for the photocatalytic oxidation of phenol, by using TiO2 suspensions. At the laboratory level, experiments were carried out in microreactors with Xe lamps. At pilot plant scale, the experiments were done at the Plataforma Solar de Almería (PSA), Spain, by using a high concentrating radiation systems (Heliomans) and solar radiation. Both systems were characterized from the point of view of the radiation field. Kinetic experiments and radiation measurements showed that kinetics are first order with respect to the phenol concentration, and a linear dependence of the reaction rate on the square root of the photonic flow. Kinetic constants (k) were calculated for both systems considering only concentration-time data. Results indicate that k values obtained at the laboratory were ten times greater than these obtained at the PSA. However, results improve when the radiation entering and the radiation absorbed by the catalyst were considered. The fitting of concentration-radiation data drives to values of the kinetic constants more similar for both systems and for all the catalyst concentrations tested. Thus, these new constants can be useful for the change of scale.