{"id":{"repo_id":"freiburg-diss","oai_identifier":"oai:freidok.uni-freiburg.de:2157"},"canonical_url":"https://search.dev.ndltd.org/etd/freiburg-diss/oai:freidok.uni-freiburg.de:2157","repository":{"repo_id":"freiburg-diss","name":"University of Freiburg","base_url":"https://freidok.uni-freiburg.de/oai/oai2.php"},"display":{"title":"Silicon concentrator cells in a two-stage photovoltaic system with a concentration factor of 300x","abstract":"In this work a rear contacted silicon concentrator cell was developed for an application in a two stage concentrator photovoltaic system. This system was developed at Fraunhofer ISE some years ago. The innovation of this one-axis tracked system is that it enables a high geometrical concentration of 300x in combination with a high optical efficiency (around 78%) and a large acceptance angle of ± 23.5° all year through. For this, the system uses a parabolic mirror (40.4x) and a three dimensional second stage consisting of compound parabolic concentrators (CPCs, 7.7x). For the concentrator concept and particularly for an easy cell integration, the rear line contacted concentrator (RLCC) cells with a maximum efficiency of 25% were developed and a hybrid mounting concept for the RLCC cells is presented. The optical performance of different CPC materials was tested and analysed in this work. Finally, small modules consisting of six series interconnected RLCC cells and six CPCs were integrated into the concentrator system and tested outdoor. A system efficiency of 16.2% was reached at around 800 W/m2 direct irradiance under realistic outdoor conditions.","abstract_html":"In this work a rear contacted silicon concentrator cell was developed for an application in a two stage concentrator photovoltaic system. This system was developed at Fraunhofer ISE some years ago. The innovation of this one-axis tracked system is that it enables a high geometrical concentration of 300x in combination with a high optical efficiency (around 78%) and a large acceptance angle of ± 23.5° all year through. For this, the system uses a parabolic mirror (40.4x) and a three dimensional second stage consisting of compound parabolic concentrators (CPCs, 7.7x). For the concentrator concept and particularly for an easy cell integration, the rear line contacted concentrator (RLCC) cells with a maximum efficiency of 25% were developed and a hybrid mounting concept for the RLCC cells is presented. The optical performance of different CPC materials was tested and analysed in this work. Finally, small modules consisting of six series interconnected RLCC cells and six CPCs were integrated into the concentrator system and tested outdoor. A system efficiency of 16.2% was reached at around 800 W/m2 direct irradiance under realistic outdoor conditions.","abstract_has_math":false,"creators":["Mohr, Andreas"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Wittwer, Volker"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":null,"date_issued":"","date_published":null,"updated_at":"2026-07-24T02:22:40Z","subjects":["compound parabolic concentrator"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://freidok.uni-freiburg.de/data/2157","outbound_label":"Repository record","outbound_source":"source_url"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Wittwer, Volker"]},{"key":"dc:creator","label":"Author","values":["Mohr, Andreas"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:type","label":"Dc Type","values":["DoctoralThesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["compound parabolic concentrator"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["In this work a rear contacted silicon concentrator cell was developed for an application in a two stage concentrator photovoltaic system. This system was developed at Fraunhofer ISE some years ago. The innovation of this one-axis tracked system is that it enables a high geometrical concentration of 300x in combination with a high optical efficiency (around 78%) and a large acceptance angle of ± 23.5° all year through. For this, the system uses a parabolic mirror (40.4x) and a three dimensional second stage consisting of compound parabolic concentrators (CPCs, 7.7x). For the concentrator concept and particularly for an easy cell integration, the rear line contacted concentrator (RLCC) cells with a maximum efficiency of 25% were developed and a hybrid mounting concept for the RLCC cells is presented. The optical performance of different CPC materials was tested and analysed in this work. Finally, small modules consisting of six series interconnected RLCC cells and six CPCs were integrated into the concentrator system and tested outdoor. A system efficiency of 16.2% was reached at around 800 W/m2 direct irradiance under realistic outdoor conditions.","In photovoltaischen Konzentratorsystemen kann durch den Einsatz von kostengünstigen konzentrierenden Optiken wie Spiegel und Linsen die Solarzellenfläche stark reduziert werden, bei gleichzeitiger Erhöhung des Systemwirkungsgrades. In dieser Arbeit wurde eine rückseitig kontaktierte Silizium-Konzentratorsolarzelle für ein zweistufiges Konzentratorsystem entwickelt. Mittels einer Zellparamteroptimierungsstudie konnte ein Zellwirkungsgrad von 25% bei 100facher Lichtkonzentration erreicht werden. Das komplette zweistufige System wird in dieser Arbeit detailliert beschrieben, und die optischen Komponenten des Systems ausführlich charakterisiert. In Außenmessungen des kompletten Systems wurden Systemwirkungsgrade von über 16% unter realistischen Bedingungen erreicht."]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Silicon concentrator cells in a two-stage photovoltaic system with a concentration factor of 300x","Silizium-Konzentratorsolarzellen für ein zweistufiges Konzentratorkonzept mit einer Konzentration von 300"]}]}],"canonical_facts":{"dc:contributor":["Wittwer, Volker"],"dc:creator":["Mohr, Andreas"],"dc:description.abstract":["In this work a rear contacted silicon concentrator cell was developed for an application in a two stage concentrator photovoltaic system. This system was developed at Fraunhofer ISE some years ago. The innovation of this one-axis tracked system is that it enables a high geometrical concentration of 300x in combination with a high optical efficiency (around 78%) and a large acceptance angle of ± 23.5° all year through. For this, the system uses a parabolic mirror (40.4x) and a three dimensional second stage consisting of compound parabolic concentrators (CPCs, 7.7x). For the concentrator concept and particularly for an easy cell integration, the rear line contacted concentrator (RLCC) cells with a maximum efficiency of 25% were developed and a hybrid mounting concept for the RLCC cells is presented. The optical performance of different CPC materials was tested and analysed in this work. Finally, small modules consisting of six series interconnected RLCC cells and six CPCs were integrated into the concentrator system and tested outdoor. A system efficiency of 16.2% was reached at around 800 W/m2 direct irradiance under realistic outdoor conditions.","In photovoltaischen Konzentratorsystemen kann durch den Einsatz von kostengünstigen konzentrierenden Optiken wie Spiegel und Linsen die Solarzellenfläche stark reduziert werden, bei gleichzeitiger Erhöhung des Systemwirkungsgrades. In dieser Arbeit wurde eine rückseitig kontaktierte Silizium-Konzentratorsolarzelle für ein zweistufiges Konzentratorsystem entwickelt. Mittels einer Zellparamteroptimierungsstudie konnte ein Zellwirkungsgrad von 25% bei 100facher Lichtkonzentration erreicht werden. Das komplette zweistufige System wird in dieser Arbeit detailliert beschrieben, und die optischen Komponenten des Systems ausführlich charakterisiert. In Außenmessungen des kompletten Systems wurden Systemwirkungsgrade von über 16% unter realistischen Bedingungen erreicht."],"dc:format.medium":["application/pdf"],"dc:subject":["compound parabolic concentrator"],"dc:title":["Silicon concentrator cells in a two-stage photovoltaic system with a concentration factor of 300x","Silizium-Konzentratorsolarzellen für ein zweistufiges Konzentratorkonzept mit einer Konzentration von 300"],"dc:type":["DoctoralThesis"]},"updated_at":"2026-07-24T02:22:40Z"}