Optical design of a linear reflecting solar concentrator with all-flat mirrors

In order to reduce the cost of solar concentrating collectors, flat mirrors were used to make reflectors in line focusing Fresnel collectors. Based on the optical principle of linear Fresnel concentration, several flat narrow silvered mirror strips were used to make a reflecting mirror unit on a tracing device. The primary mirrors of linear Fresnel collector were consisted of reflecting mirror units with different focal lengths. With new idea of receiver design, a double-arc secondary reflector was designed in order to collect more radiation and lessen the aperture of the receiver. Good results were obtained from the simulation of ray trace and experiments of testing device. The design of the reflecting mirror unit has the advantages of low cost, good sunlight concentration, expandable primary mirror field, very low wind load and stable tracing. The small scale concentrators can be applied to steam generation which can provide process heat for agricultural products drying. The large scale concentrators can provide steam for thermal electricity.