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Performance Evaluation of Non-Uniform Illumination on a Transverse Bifacial PVT Receiver in Combination with a CPC Geometry
University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology. (Energy System)ORCID iD: 0000-0002-0539-3291
University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.ORCID iD: 0000-0002-8156-2587
University of Gävle, Faculty of Engineering and Sustainable Development, Department of Building Engineering, Energy Systems and Sustainability Science, Energy Systems and Building Technology.
2019 (English)In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 194, p. 696-708Article in journal (Refereed) Published
Abstract [en]

PVT collectors co-generate electricity and heat from the same gross area, thus achieving higher combined heat and electric yields. A comprehensive evaluation has been carried out on non-uniform solar irradiation profile distributions on four symmetric low concentration CPC PVT (LCPVT) solar collector design concepts. Additionally, an electrical and thermal performance evaluation of symmetric truncated LCPVT solar collectors based on a CPC reflector geometry with a central transverse bifacial PVT receiver has been carried out, through a numerical ray-tracing model software and a multi-paradigm numerical computing environment software. A simplified thermal (quasi-dynamic testing method for liquid heating collectors described in the international standard for solar thermal collectors ISO 9806:2017) and electrical performance models were employed to evaluate the LCPVT design concepts. The evaluation was carried out for heating Domestic Hot Water (DHW) for a Single Family House (SFH) in Fayoum (Egypt), where energy yields between 351 and 391 kWh/m2/year have been achieved. The non-uniform solar irradiation assessment showed that the PV cells are exposed to high levels of radiation due to the specific reflector geometry. Furthermore, the study showed that the CPC geometries are very sensitive to the shading effect, as partial shadowing is substantial for high incidence angles.

Place, publisher, year, edition, pages
2019. Vol. 194, p. 696-708
Keywords [en]
CPC PVT collector, LCPVT, Transverse bifacial PVT receiver, Irradiation flux distribution, Performance evaluation, Ray-tracing
National Category
Energy Systems
Research subject
Sustainable Urban Development
Identifiers
URN: urn:nbn:se:hig:diva-30967DOI: 10.1016/j.solener.2019.10.069ISI: 000502888500067Scopus ID: 2-s2.0-85074877472OAI: oai:DiVA.org:hig-30967DiVA, id: diva2:1370260
Note

This research was funded by Eureka Eurostars, under project number E10625

Available from: 2019-11-14 Created: 2019-11-14 Last updated: 2021-11-18Bibliographically approved
In thesis
1. Development of Concentrating Photovoltaic-Thermal Solar Collectors
Open this publication in new window or tab >>Development of Concentrating Photovoltaic-Thermal Solar Collectors
2021 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Fossil fuels have greatly improved human living standards and saved countless lives. However, today, their continued use threatens human survival, as CO2 levels rise at an unprecedented pace to levels never seen during human existenceon earth.

This thesis aims at gathering knowledge on solar energy in general and photovoltaic thermal (PVT) and concentrating photovoltaic thermal (C-PVT) in particular. This thesis establishes several key research questions for PVTs and C-PVT collectors and attempts to answer them.

A comprehensive market study of solar thermal (ST), photovoltaic (PV) and PVT was conducted to obtain prices and performance. Simulations of the energy output around the world were conducted. A ratio between ST and PV annual output was defined to serve as a tool for comparison and plotted on a world map.

A key issue for PVT collectors is how to encapsulate the solar cells in a way that, amongst other things, protects the cell from the thermal expansion of the receiver, has a high transparency, and insulates electrically while at the same time conducts the heat to the receiver. In order to be useful, this analysis must also consider the impacts on the production processes. Several prototypes were constructed, a test methodology was created, and the analysis of the results enabled several conclusions on the validity of the different silicon encapsulations methods.

This thesis relies heavily on collector testing with 30 different prototypes of C-PVTs being designed and constructed. Most testing was conducted using steady state method but quasi dynamic was also carried out. From this work, several guidelines were created for the design of collectors in terms of reflector geometry, cell size, string configuration, encapsulation method and several other design aspects. These analyses were complemented with thermal simulations (COMSOL & ANSYS), string layout (LT SPICE) and evaluation of existing installations. Two novel design ideas came from this thesis work, which the author will patent in the coming year. Additionally, raytracing work has been conducted and a new reflector geometry more appropriate for C-PVTs has been found to significantly improve the annual performance. Finally, the current and future position of PVTs in the global energy market is discussed.

Abstract [sv]

Denna avhandling syftar till att samla kunskaper om solenergi i allmänhet och PVT-hybrider som ger både el och värme i synnerhet. Särskilt stort intresse riktas mot koncentrerande C-PVT-hybrider.

Avhandlingen ställer ett flertal viktiga forskningsfrågor för PVT och CPVT solfångare och försöker svara på dem. En omfattande marknadsstudie av solvärme (ST), solceller (PV) och PVT har genmförts för att erhålla priser och prestanda.

Studien användes som underlag för energiutbytessimuleringar runt om i världen. Ett förhållande för kvoten mellan energiutbytena för ST och PV definierades för att användas som ett verktyg för en jämförelse mellan systemen och ritades in på världskartan.

En viktig fråga för PVT-solfångare är hur man kapslar in solcellerna på ett sätt som bland annat skyddar solcellen från absorbatorns värmeutvidgning, har hög transparens och isolerar elektriskt samtidigt som den leder värmen till absorbatorn. För att vara användbar måste denna analys också ta hänsyn till produktionsprocesserna. Flera prototyper konstruerades, en testmetod utarbetades och analysen av resultaten möjliggjorde ett antal viktiga slutsatser om funktionen hos de olika silikoninkapslingsmetoderna.

Denna avhandling baseras på verkningsgradstestning av 30 olika prototyper av C-PVT. De flesta testerna utfördes med den statiska testmetoden, men kvasidynamisk testning har också använts. Från denna testning utarbetades riktlinjer för konstruktionen av solfångarna när det gäller reflektorgeometri, cellstorlek, strängkonfiguration och inkapslingsmetod. Dessa analyser kompletterades med termiska simuleringar (COMSOL & ANSYS), stränglayout (LT SPICE)och utvärdering av befintliga installationer. Ett antal nya designidéer kommer att patenteras under de kommande åren. En ny reflektorgeometri för C-PVT som förbättrar det årliga energiutbytet har utarbetats och testats. Slutligen diskuteras PVTs nuvarande och framtida position på den globala marknaden försolenergisystem.

Place, publisher, year, edition, pages
Gävle: Gävle University Press, 2021. p. 194
Series
Doctoral thesis ; 21
Keywords
Solar Energy, Photovoltaic-Thermal (PVT), Concentration, Collector Testing, Silicon Cell Encapsulation, Ray Tracing, Market Survey, String Layout, Prototype Collectors, Solenergi, Fotovoltaisk-termisk (PVT), Koncentration, Solfångarprovning, Inkapsling av kiselceller, Strålgångsberäkning, Marknadsundersökning, Strängdesign, Solfångarprototyper
National Category
Energy Engineering
Research subject
Sustainable Urban Development
Identifiers
urn:nbn:se:hig:diva-35411 (URN)978-91-88145-67-3 (ISBN)978-91-88145-68-0 (ISBN)
Public defence
2021-08-27, Room 13:111, Kungsbäcksvägen 47, Gävle, 10:15 (English)
Opponent
Supervisors
Available from: 2021-06-17 Created: 2021-03-09 Last updated: 2024-08-29Bibliographically approved
2. Reflector Optimization for Low Concentration Photovoltaic-Thermal Solar Collectors
Open this publication in new window or tab >>Reflector Optimization for Low Concentration Photovoltaic-Thermal Solar Collectors
2022 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The alarming new global warming and increasing awareness related to climate change (mainly due to the high emissions of carbon dioxide) in recent decades linked all nations into a common cause, which requires ambitious efforts to combat climate change by adapting energy systems to its effects.

The knowledge gain presented in this dissertation establishes the foundations for the development of a more efficient concentrating photovoltaic-thermal (PVT) solar collector. The presented work provides decision-makers with a broader, more detailed performance assessment of concentrating PVT solar collectors.

A critical issue for concentrating PVT solar collectors lies in the respective reflector shape, which will determine, to some extent, the overall performance of the CPVT collector. Therefore, several symmetrical reflector design concepts were designed and optimized through Monte Carlo ray-tracing software. With the support of a MATLAB script, a simulation test methodology has been developed and optimized, allowing a more thorough analysis of the results regarding the viability of the different reflector shapes, which established the compound parabolic collector (CPC) to be the most appropriate reflector geometry for PVT solar collectors.

Moreover, CPC-PVT solar collectors (based on the findings described above) were designed, built and outdoor tested (under steady-state method guidelines) for their thermal and electrical peak efficiencies, heat losses and incidence angle modifier (IAM) coefficients.

The developments achieved in this dissertation significantly enhanced the annual performance of CPC-CPVT solar collectors, which closes the efficiency/performance gap between mature technologies such as PV modules or ST collectors.

Abstract [sv]

Den alarmerande globala uppvärmningen och den ökande medvetenheten i samband med klimatförändringar på grund av de höga utsläppen av koldioxid har samlat alla nationer till den gemensama uppgiften, att bekämpa klimatförändringarna och effekterna av dem genom anpassning av energisystemen.

Den kunskapsökning som presenteras i denna avhandling utgör grunden för utvecklingen av effektivare koncentrerande solcellsmoduler. Det presenterade arbetet möjliggör en bredare och mer detaljerad analys av prestandan hos koncentrerande PVT-moduler.

En kritisk fråga för den koncentrerande PVT solfångarens prestanda är reflektorns geometri, som i hög grad påverkar verkningsgraden. Därför designades och optimerades flera symmetriska reflektorgeometrier. Med hjälp av en Monte Carlo ray-tracing programvara. Med stöd av ett MATLAB-skript har en simuleringstestmetodik utvecklats vilken möjliggör en mer ingående analys av funktionen hos de olika reflektorformerna. Den visade att compound parabolic collector (CPC) är den mest lämpliga reflektorgeometrin för ej solföljande koncentrerande PVT-solfångare.

Dessutom konstruerades, byggdes och testades CPC-PVT-solfångare, baserat på de resultat som beskrivs ovan, enligt steady-state-metoden, för att få termiska och elektriska verkningsgrader värmeförluster och infallsvinkelberoende.

Den utveckling som uppnåtts i denna avhandling förbättrar den årliga prestanda hos CPVT-solfångare avsevärt, vilket minskar effektivitetsgapet till mognare tekniker som solcellsmoduler och termiska solfångare.

Place, publisher, year, edition, pages
Gävle: Gävle University Press, 2022. p. 153
Series
Doctoral thesis ; 26
Keywords
Photovoltaic-thermal collector, experimental assessment, collector performance assessment, optical efficiency, concentrating PVT solar collector, ray tracing, Fotovoltaisk-termisk kollektor, experimentell utvärdering, prestandautvärdering, optisk effektivitet, koncentrerande PVT-solfångare, strålgångsanalys
National Category
Energy Systems
Identifiers
urn:nbn:se:hig:diva-37391 (URN)978-91-88145-81-9 (ISBN)978-91-88145-82-6 (ISBN)
Public defence
2022-01-28, 13:302, Gävle, 09:00 (English)
Opponent
Supervisors
Available from: 2022-01-04 Created: 2021-11-18 Last updated: 2024-08-29Bibliographically approved

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Cabral, DiogoGomes, JoãoKarlsson, Björn O.

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