LAUSR

Abstract This work presents a novel low-cost parabolic trough solar collector in which a two-phase closed thermosiphon (TPCT) heat pipe made of stainless steel and composed of evaporation and condensation parts with a total length of 285 cm has been utilized to capture solar heat. The evaporation part with the length of 240 cm positioned in the center of the collector’s reflector has been coated with selective coating and is insulated from environment using twin wall evacuated glass tube. The condensation part with the length of 45 cm located inside a cylindrical manifold thermally insulated using glass wool transfers the vaporization latent heat of vapor existing inside the condensation part to heat transfer fluid (HTF) flowing inside the manifold, and heats it. CuO - H 2 O nanofluid prepared by mixing distilled water and copper oxide nonopowder with 1% weight concentration has been utilized as the working fluid of the TPCT heat pipe. The collector has been installed on a low-priced sensorless dual-axis solar tracker operating using offline data obtained from solar map equations. The tracker has been chosen as dual-axis to guarantee continuously keeping the reflector’s aperture perpendicular to the sun ray. The proposed parabolic trough solar collector has been built, and comparative experimental measurements obtained from the operation of the built solar collector, a state-of-the-art evacuated tube solar collector (commercial high-efficient evacuated tube solar collector ETC-20) and a state-of-the-art flat-plate solar collector (commercial high-efficient flat-plate solar collector FPC-A26) under identical realistic conditions are given. Experimental measurements and comparison prove the following points which are the novelties and contributions of this research work: • The novel parabolic trough solar collector presented in this study provides higher thermal efficiency compared to the state of the art of both evacuated tube solar collectors (ETC-20) and flat-plate solar collectors (FPC-A26) available in the market. • It provides flatter thermal efficiency curve. • It provides higher power production density (ratio of peak output power to aperture area). • It has lower construction cost and a reasonable ratio of price to power production.