Cost effective non-evacuated receiver for line-concentrating solar collectors characterized by experimentally validated computational fluid dynamics model

Solar thermal technology promises to be a significant component of the future renewable energy mix. As the most mature solar thermal technology, parabolic trough concentrators (PTC) are the focus of considerable research. Conventional PTC use evacuated receivers, which contribute 30% of the solar field cost, not including significant failure (55% due to broken glass envelopes and 29% due to loss of vacuum arising due to failure of glass to metal seal). We report a non-evacuated receiver with a modular design for easier assembly and superior thermal performance for a PTC made of reflective strips of mirrored glass with a rim angle of 60 degrees. The receiver performance is estimated using our own ray-tracing software and computational fluid dynamics (CFD) simulations using a model that we have validated with our own experimental rig. Critical parameters like the width of the mirror strip, the emissivity of solar selective coating, insulation material, and reflectivity of optical cavity walls have been analyzed in this study. A scaled-up model of the proposed novel receiver with a heat transfer fluid conduit diameter of 70 mm has been simulated to compare the performance with the commercial SCHOTT PTR (R) 70. The cost of this receiver is estimated to be $30/m as compared to up to $250/m for SCHOTT PTR (R) 70 with comparable performance. The modular nature of the receiver and reflector gives operational and maintenance flexibility and facile part replacement in case of damage, resulting in low-cost operation.