Solar-thermal system modelling

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Two days of modelled output for the parabolic trough collector based equations from Patnode in models/solar/solar_field.a4l. None of the dynamics or control system effects are considered yet.

Some work is underway to tackle solar-thermal system modelling with ASCEND. Our immediate aim is to be able to produce an annual performance model of the SEGS VI parabolic trough system including the sun position, tracking, concentrator, receiver, power block, parasitics and startup/shutdown with cloud transients. We aim to produce a model that can be benchmarked against other solar thermal modelling software under the modelling guidelines of the SolarPACES round 2 'tool cross check'. Much remains to be done, but we hope that the result will be an accurate and fully open-source model that is ready for adaptation by a wide range of users including researchers, students and industry.

Progress so far on this task includes:

• steady-state model of a parablic trough collector models/solar/solar_field.a4l following the approach of Patnode
• data reader for TMY2, TMY3, CSV weather data files
• calculation of sun position by NREL, Grena and Duffie & Beckman algorithms.
• power cycle models: Rankine cycle models/johnpye/fprops/rankine_fprops.a4c and also CCGT models. More detail still required.

Key issues remaining:

• more detailed power block model and/or simplified correlation of power block behaviour as per Patnode.
• implementation of aspects of control logic including
  • collector off-steer during excess solar gain,
  • cut-off triggering during low cloud,
  • turbine ramp rate and grid syncronisation,
  • start-of-day warm-up period.
• event handling as a general feature to aid in the implementation of the above control logic.

Contributors to aspects of this work include Vikram Kadam, Ksenija Bestuzheva, Ben Allan, Emily Do and John Pye.