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Design and development of a beam down reflector
Thesis (MEng)--Stellenbosch University, 2023.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2023
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| _version_ | 1867613900622528512 |
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| access_status_str | Open Access |
| author | Keech, Amy |
| author2 | Hoffmann, J. E. |
| author_browse | Hoffmann, J. E. Keech, Amy |
| author_facet | Hoffmann, J. E. Keech, Amy |
| author_sort | Keech, Amy |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2023. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/127323 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:43:29.841Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2023 |
| publishDateRange | 2023 |
| publishDateSort | 2023 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/127323 Design and development of a beam down reflector Keech, Amy Hoffmann, J. E. Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering. Solar thermal energy Renewable natural resources Solar concentrators UCTD Thesis (MEng)--Stellenbosch University, 2023. ENGLISH SUMMARY: Solar thermal is considered a favourable form of renewable energy in South Africa due to the availability of high solar irradiation levels. The finite supply of fresh water creates a demand for desalination plants. However, desalination processes are energy intensive. Arid regions that are water scarce have high levels of direct normal irradiation that can be utilised for desalination instead of fossil fuel resources. Integrating desalination systems with solar energy technologies can reduce the pollution, emissions and global warming effects of conventional desalination systems. The study aimed to investigate the feasibility of using a beam down reflector as part of a Concentrating Solar Thermal (CST) system. The objectives were to simulate a full-scale CST plant in ray tracing software and to conduct a theoretical case study within a South African context to determine the feasibility of integrating a beam down CST system with a desalination system. Tonatiuh ray tracing software was used to predict the power output, peak flux, and flux distribution incident on the receiver surface. Tonatiuh was validated by simulating a beam down CST plant at the Stellenbosch University Helio40 solar research facility and comparing the ray-traced results to experimentally measured results and theoretical results from an analytical flux approximation model. The analytical model used the "Heliostat Field Layout CALculations (HFLCAL)" method. A reflector was designed, fabricated, and installed at the Helio40 facility, and experiments were conducted for the ray tracer validation process. The analytical model agreed well with ray tracing predictions with a percentage difference of less than 1%. The shape of the focal spots was well predicted by the ray tracer. However, the peak flux values were underpredicted by up to 63% when ray-traced results were compared to experimental results. This discrepancy was due to the available flux sensor operating at the lowest end of its measurement range. A full-scale beam down CST desalination plant was simulated in Tonatiuh as part of a case study. The case study investigated the feasibility of the plant providing clean water to a rural community in the Northern Cape. The plant design was based on meeting specific requirements such as low cost, simplicity, and robustness. The heliostat field was based on the Helio pods at the Helio100 facility. It was found that two Helio100 fields are required to meet the needs of the community. An economic assessment was conducted to determine the financial feasibility of the system. It was found that the tower and heliostat field were the most capital-intensive parts of the system. The CSTD (Concentrating Solar Thermal Desalination) plant outperformed the solar still when a large amount of water was required, and over a five-year lifespan, the CSTD plant was predicted to be a fifth of the cost of a solar still plant. From these results, it was concluded that the use of a beam down reflector as part of a CST system was feasible. AFRIKAANSE OPSOMMING: Die son-termiese energie word as ’n toepaslike vorm van hernubare energie in Suid-Afrika beskou as gevolg van die beskikbaarheid van hoe sonbestralingsvlakke. Die beperkte aanbod van vars water skep ’n vraag na ontsoutingsaanlegte. Ontsoutingsprosesse is egter energie-intensief. Droe streke waar water skaars is, het hoe vlakke van direkte normale bestraling wat vir ontsouting gebruik kan word in plaas van fossielbrandstofbronne. Die integrasie van ontsoutingstelsels met sonkragtegnologiee kan die besoedeling, emissies en aardverwarmingseffekte van konvensionele ontsoutingstelsels verminder. Die studie het ten doel gehad om die uitvoerbaarheid van die gebruik van ’n afstraal weerkaatser as deel van ’n CST-stelsel te ondersoek. Die doelwitte was om ’n volskaalse CST-aanleg in straalopsporingsagteware te simuleer en om ’n teoretiese gevallestudie binne ’n Suid-Afrikaanse konteks uit te voer om die haalbaarheid daarvan te bepaal om ’n afstraal weerkaatser CST-stelsel met ’n ontsoutingstelsel te integreer. Tonatiuh straalopsporingsagteware is gebruik om die kraguitset, piekvloed en vloedverspreiding wat op die ontvangeroppervlak voorkom, te voorspel. Tonatiuh is gestaaf deur ’n straalafwaartse CST-aanleg by die Universiteit Stellenbosch Helio40-sonnavorsingsfasiliteit te simuleer en die resultate te vergelyk met eksperimenteel gemete resultate en teoretiese resultate van ’n analitiese vloedbenaderingsmodel. Die analitiese model het die "Heliostat Field Layout CALculations-metode (HFLCAL)" gebruik. ’n Weerkaatser is ontwerp, vervaardig en geinstalleer op die Helio40-fasiliteit, en eksperimente is uitgevoer vir die straalspoorderstawingssproses. Die analitiese model het goed ooreengestem met straalspoorvoorspellings met ’n persentasieverskil van minder as 1%. Die vorm van die brandpunte is goed voorspel deur die straalspoorder. Die piek vloedwaardes is egter met tot 63% ondervoorspel wanneer straalgespoorde resultate met eksperimentele resultate vergelyk is. Hierdie teenstrydigheid was te wyte aan die beskikbare vloedsensor wat aan die laagste punt van sy meetreeks werk. ’n Volskaalse afstraal CST-ontsoutingsaanleg is in Tonatiuh gemodelleer as deel van ’n gevallestudie. Die gevallestudie het die uitvoerbaarheid van die aanleg ondersoek om skoon water aan ’n landelike gemeenskap in die Noord-Kaap te verskaf. Die aanlegontwerp was gebaseer op voldoening aan sekere vereistes soos lae koste, eenvoud en robuustheid. Die heliostaatveld was gebaseer op die Heliopod by die Helio100-fasiliteit. Daar is gevind dat twee Helio100-velde benodig word om in die behoeftes van die gemeenskapte voorsien. ’n Ekonomiese beoordeling is gedoen om die finansiele uitvoerbaarheid van die stelsel te bepaal. Daar is gevind dat die toring en heliostaatveld die mees kapitaalintensiewe dele van die stelsel is. Die CSTontsoutingsaanleg het beter gevaar as die sonkragtoevoer wanneer ’n groot hoeveelheid water benodig word, en oor ’n leeftyd van vyf jaar is voorspel dat die CST-aanleg ’n vyfde van die koste van ’n sonkragaanleg sou wees. Uit hierdie resultate is tot die gevolgtrekking gekom dat die gebruik van ’n afstraal weerkaatser as deel van ’n CST stelsel haalbaar was. Masters 2023-03-02T09:39:34Z 2023-05-18T07:16:05Z 2023-03-02T09:39:34Z 2023-05-18T07:16:05Z 2023-03 Thesis http://hdl.handle.net/10019.1/127323 en_ZA Stellenbosch University xx, 106 pages : illustrations, maps, includes annexures application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Solar thermal energy Renewable natural resources Solar concentrators UCTD Keech, Amy Design and development of a beam down reflector |
| title | Design and development of a beam down reflector |
| title_full | Design and development of a beam down reflector |
| title_fullStr | Design and development of a beam down reflector |
| title_full_unstemmed | Design and development of a beam down reflector |
| title_short | Design and development of a beam down reflector |
| title_sort | design and development of a beam down reflector |
| topic | Solar thermal energy Renewable natural resources Solar concentrators UCTD |
| url | http://hdl.handle.net/10019.1/127323 |
| work_keys_str_mv | AT keechamy designanddevelopmentofabeamdownreflector |