A software tool for assisting in the preliminary performance modelling of central receiver solar thermal plants was developed using Matlab®. Scope was limited to the thermodynamic study of the power cycle and receiver. The receiver model was validated by comparing results to published data. The model was able to simulate billboard, C-cavity and cylindrical receivers within 1% in cases involving single-phase fluids and by at most 3% - 5% for water. Performance studies were conducted to demonstrate the usefulness of the model. Power cycle studies investigated the performance limits on non-reheated cycles as well as the effects of reheat and regenerative feedwater heating. The results showed expected trends of efficiency increasing with turbine inlet temperature and pressures. Also, efficiency was shown to increase asymptotically with number of feedwater heaters and reheat was shown to improve exhaust quality and efficiency. Billboard and cylindrical receivers were studied in detail using a number of heat transfer fluids, namely thermal oil, molten salt, molten sodium and water to compare the relative performance over a range of rated powers. Water and thermal oil were shown to be the best performing fluids for use in billboards and cylindrical receivers, respectively. Water and salt were shown to require the least area for use in billboards and cylindrical receivers, respectively. The effects of power cycle performance on receiver performance and size were investigated from which it was found that receiver efficiency increases marginally with power cycle efficiency but the required area is reduced significantly.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uct/oai:localhost:11427/18584 |
| Date | January 2011 |
| Creators | Smith, Lee |
| Contributors | Bennett, Kevin |
| Publisher | University of Cape Town, Faculty of Engineering and the Built Environment, Energy Research Centre |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Master Thesis, Masters, MSc |
| Format | application/pdf |
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