Model of solar diffuse radiation transmission through circular perforated louvers and experimental verification

The main problem of previous methods for diffuse radiation transmission calculation of shading louvers is that they can only deal with flat slats. Taking the radian and perforation rate of louvers into consideration, a new model of solar diffuse radiation transmitted through circular perforated louvers was established and experimentally verified in this paper. Firstly, taking two adjacent circular perforated louvers as the research object, the new calculation model was established, and based on the model, a computer program was developed with MATLAB, which can be used to study the impact of shape, size, rotation angle, and surface optical properties of circular perforated louvers on diffuse radiation transmission. Secondly, an experimental set-up was built to verify the new model, and the results showed that the model predictions compared well with the experimental data. Finally, the error of the conventional calculation methods was analyzed, and the results showed that, the “flat slat model” led to overestimation of the transmittance of diffuse radiation, and the relative error increased from 2.9% to 13.8% when the rotation angle increasing from 0 to 85°.