Dynamic Performance Evaluation of the HelioTrough® Collector Demonstration Loop–Towards a New Benchmark in Parabolic Trough Qualification

The HelioTrough collector developed in industry-research cooperation is a parabolic trough collector with significantly increased aperture width and length. At the end of 2009, HelioTrough collectors were installed and have been continuously operated in the SEGS-V field at Kramer Junction (California, USA) for testing and demonstration purposes since then. The evaluation of thermal collector performance is based on measurement equipment installed in the test loop, in particular flow meters, temperature sensors, and tracked pyrheliometers. Two kinds of performance analysis are carried out: A standard energy balance evaluation identifies and analyses periods of steady-state operation from a full range of field measurement data and delivers collector efficiency data for specific operating conditions. The advanced evaluation based on dynamic models delivers performance equation parameters and their uncertainties, and allows using more test data, also from non-steady-state test periods according to an advanced test method for solar field performance. The evaluation of the thermal test data includes a thorough analysis of the measurement equipment and a detailed uncertainty analysis for rating the test equipment and resulting data quality. The test results show the successful application of the advanced test and evaluation method and prove the high performance parameters of the HelioTrough (optical efficiency 0.816, thermal efficiency > 75% at nominal operating conditions). This transfer from pilot scale measurements to bankable performance parameters may serve as benchmark for the up-coming large-scale CSP projects.