Theoretical analysis of reflected ray error from surface slope error and   their application to the solar concentrated collector
  Surface slope error of concentrator is one of the main factors to influence the performance of the solar concentrated collectors which cause deviation of reflected ray and reduce the intercepted radiation. This paper presents the general equation to calculate the standard deviation of reflected ray error from slope error through geometry optics, applying the equation to calculate the standard deviation of reflected ray error for 5 kinds of solar concentrated reflector, provide typical results. The results indicate that the slope error is transferred to the reflected ray in more than 2 folds when the incidence angle is more than 0. The equation for reflected ray error is generally fit for all reflection surfaces, and can also be applied to control the error in designing an abaxial optical system. 
Weidong Huang
physics.optics