A new parabolic trough solar collector

This paper presents a new parabolic trough array designed to provide the thermal energy required to drive a organic rankine cycle (ORC) power generation system. The parabolic trough collectors have been installed in the National Solar Energy Centre at CSIRO Energy Technology in Newcastle, NSW. They consist of four rows of 18 mirrors each in a 2x2 matrix with a total aperture area of approximately 132m2. The mirrors reflect the sun’s irradiation onto a laterally aligned, 40mm copper absorber tube which has been coated with a semi-selective paint. The absorber operates in a 50mm non-evacuated glass tube to minimize convection losses. Thermal oil is circulated inside the absorber tube, and transfers the heat to a ORC FP6 unit sourced from Freepower Ltd. in the United Kingdom. The mirror modules were developed and fabricated by the ANU Solar Thermal Group using thin low iron back silvered glass bonded to a sheet steel substrate. The support structure was developed as a collaborative effort between CSIRO Energy Technology and ANU. It features a box truss supported on semi circular hoops running on rollers for single axis tracking. The trough array is actuated by a PC-controlled stepper motor to achieve the desired target angle. Before installation of the trough array, the optical performance was investigated with regard to the flux mapping onto the receiver tube. This paper presents results for irradiation capture and intensity over the receiver width of a single trough module. 1