Current Performance and Potential Improvements in Solar Thermal Industrial Heat

A representative current state-of-the-art system using parabolic trough technology was developed using data from a system recently installed in Tehachapi, California. A simulation model was used to estimate the annual energy output from the system at three different insolation locations. Based on discussions with industry personnel and within NREL, we identified a number of technologyimprovements that offer the potential for increasing the energy performance and reducing the energy cost of the baseline system. The technology improvements modeled included an evacuated-tube receiver, an antireflective coating on the receiver tube, an improved absorber material, a cleaner reflecting surface, a reflecting surface that can withstand contact cleaning, and two silver reflectors.The properties associated with the improvements were incorporated into the model simulation at the three insolation locations to determine if there were any performance gains. The results showed that there was a potential for a more than 50% improvement in the annual energy delivered by a 2677 m2 system incorporating a combination of the enumerated technology improvements. We discuss thecommercial and technological status of each design improvement and present performance predictions for the trough-design improvements. We report on the economic impacts of these design improvements in Williams and Hale [1993].