Numerical integration of solar, electrical and thermal exergies of photovoltaic module: a novel thermophotovoltaic module

Significance 

Renewable energy has the potential not only to complement but possibly replace fossil energy. A main focus is clean solar energy which has attracted significant attentions from both academics as well as policy makers owing to its sustainability compared to other types of renewable energy sources. Until now, solar thermal and photovoltaic systems are the two main methods for harvesting solar energy due to their great potential integration with hybrid systems for constant power generation. However, the drop in electrical conversion efficiency with an increase in the temperature of the solar cell is the current major challenge in using photovoltaic modules. To this end, there is a great need to control the temperature in order to enhance the efficiency of the solar cell. This includes the use of the waste heat generated from the photovoltaic for other thermal operations.

To this effect, University of Manchester-based researchers: Chukwuma Ogbonnaya (PhD candidate), Professor Ali Turan and Dr. Chamil Abeykoon developed a novel thermophotovoltaic module by exploring the thermodynamics of solar cells photovoltaic generation. This was fundamentally based on integrating the solar, electrical and thermal exergies of a photovoltaic module. The main objective was to better understand the influence of the variations in temperature and solar radiation on the operation of photovoltaic devices. The work is currently published in the journal, Solar Energy.

For accurate modeling of photovoltaic power generation, a computer iterative code-based model was utilized taking into consideration the transcendental equation created by the photovoltaic output voltage. Therefore, the code-based model which allows user manipulation was effectively used to implement a thermophotovoltaic model by integrating the solar, electrical and thermal exergies of the photovoltaic module. Next, the proposed model was implemented in MATLAB and parametric studies conducted to determine the effects of the changes in temperature and solar radiation on the electrical and thermal exergy flow patterns during power generation. Notably, the proposed thermophotovoltaic model was based on several assumptions.

The research team pointed out that heat is an essential parameter for power generation in photovoltaic systems. Therefore, electricity can only be generated exponentially when the temperature of the solar cell exceeds a critical temperature of 223.5K, as observed in most solar cells. However, beyond a critical value, very high temperatures degrade the open-circuit voltage thus leading to low photovoltaic conversion efficiency. Unlike block-based modeling, code-based modeling used programmable codes which allowed user definitions manipulation thus enhancing the ease of system integration and implementation.

The results generated by the proposed thermophotovoltaic model agreed well with the established photovoltaic physics and thermodynamics. For instance, the photovoltaic performance of the 45 W photovoltaic module used could improve by 51% if the waste heat generated is used for other thermal operations. Additionally, the code-based model approach would allow incorporation of more functional parameters and conditions that will improve results’ accuracy.

In summary, a thermophotovoltaic model based on the integration of solar, electrical and thermal exergies of photovoltaic modules is developed. In general, the approach proposed by the University of Manchester scientists would be useful for engineers in designing experiments for the quantification of thermal and electrical outputs of photovoltaic modules at varying temperatures and solar radiation. This would facilitate heat recovery measures for the optimization of both photovoltaic and photovoltaic-thermal systems.

Numerical integration of solar, electrical and thermal exergies of photovoltaic module: a novel thermophotovoltaic module - Advances in Engineering
Fig. A: Diagram of exergy flow in a photovoltaic module
Numerical integration of solar, electrical and thermal exergies of photovoltaic module: a novel thermophotovoltaic module - Advances in Engineering
Fig. B: Effects of temperature variations on the photocurrent and voltage of the PV module
Numerical integration of solar, electrical and thermal exergies of photovoltaic module: a novel thermophotovoltaic module - Advances in Engineering
Fig. C: Effects of temperature variations on the thermal and electrical exergy flows from the PV module
Numerical integration of solar, electrical and thermal exergies of photovoltaic module: a novel thermophotovoltaic module - Advances in Engineering
Fig. D: Effects of temperature variations on the energy and exergy efficiencies of the PV module

About the author

Chukwuma Ogbonnaya received the B.Eng. (Hons.) degree in Polymer and Textile Engineering from the Federal University of Technology, Owerri, Nigeria in 2005 where he won Federal Government Undergraduate scholarship. He received Masters of Science (MSc) in Manufacturing Systems Engineering from The University of Warwick, United Kingdom in 2014 under the overseas masters scholarship programme of the Ebonyi State government, Nigeria.

He is currently a Doctoral researcher/Teaching Assistant at the School of Mechanical, Aerospace and Civil Engineering in The University of Manchester, UK under the PhD scholarship programme of the Petroleum Technology Development Fund (PTDF) Nigeria. He has Postgraduate Diploma in Education (PGDE) from Usmanu Danfodiyo University, Sokoto, Nigeria; proficiency certificate in management from Nigerian Institute of Management and has received the Associate Fellowship of the Higher Education Academy (AFHEA), United Kingdom. After completing the MSc degree, he worked as a Lecturer in the Department of Chemical Engineering at Alex Ekwueme Federal University Ndufu-Alike Ikwo, Nigeria. His current doctoral research interests include: Thermodynamic and thermoeconomic analysis of renewable energy technologies, modeling and simulations; computational fluid dynamics; heat and mass transfer; reliability, manufacturability, sizing and optimisation of renewable energy systems, power-to-gas technologies based on renewable energy and fuel cells.

He is a Member of the professional bodies, including ISES, PIN and NSE. Moreover, he was the winner of The University of Manchester sponsored place for OpenCon2018 held in York University, Toronto, Canada. He is a STEM Ambassador with the Transpennine Group, Manchester as well as an Engineering Social Responsibility (ESR) fellow at the School of Mechanical, Aerospace and Civil Engineering in The University of Manchester, UK.

About the author

Professor A. Turan joined UMIST (now the University of Manchester) in July 2002 as a Professor of Power Generation in the Department of Mechanical, Aerospace and Manufacturing Engineering after having spent all of his professional life in the USA. He has been involved over the years in a number power generation research projects aimed at thermodynamically efficient and environmentally friendly routes to energy conversion/utilization including fuel cell/ gas turbine cycle design and development. He is the Group leader for the Energy and Multiphysics Research Activity of the Fluids Academic Interest Group in the School of MACE and has supervised a large number of PhD students. He received a Ph.D. in the area of Computational Fluid Dynamics/Combustion from the University of Sheffield, UK in 1978. Since then he has had forty years of experience in developing and implementing a variety of state-of-the-art algorithms in challenging fluid dynamics, heat and mass transfer problems in industry primarily in the energy conversion/propulsion and thermal manufacturing/processing industries.

He has substantial experience in the development and application of advanced turbulence modelling, submodels for two-phase flow, coal and oil combustion modelling, radiation and heat transfer analysis, flow instabilities including thermo-acoustic instability. He has also been heavily involved in the development of advanced computational techniques and algorithms (spectral element, high order finite volume) and application for the simulation of laminar, turbulent, non/reacting, multi-species, multi-phase flows in engineering configurations.

He has obtained substantial external research and development funding ($10 million) and managed a variety of modelling studies for major gas turbine manufacturers including NASA, DoD and DoE. In that capacity, he has provided technical guidance to a diverse group of capable individuals with varying interests and responsibilities. He has also consulted in the areas of propulsion/combustion, energy systems/electrical power generation, environmental science, etc. for a variety of international companies including GE, Textron Lycoming, Textron Defense Systems, IHI Kobe Steel, MTU and Arthur D. Little. He has collaborated with some of the US national research laboratories including Argon and Sandia in executing a variety of complex research projects where interdisciplinary teamwork is required.

He has published over 130 papers and reports in the areas of numerical algorithm development, fundamental and application oriented case studies covering advanced turbulence modelling, multi-phase multi-species flow, combustion, radiation and various heat and mass transfer problems. Some of the recent research activities cover areas focused specifically in investigating the internal aerothermal design and development of fuel cells including electrochemical aspects (SOFC in particular) for combined cycle applications utilizing biomass derived fuels.

About the author

Chamil Abeykoon received the B.Sc. (Hons.) degree in mechanical engineering from the University of Peradeniya, Sri Lanka, in 2007, with the award of best performance in mechanical engineering, and the Ph.D. degree in mechanical engineering from the Queens University Belfast, U.K., in 2011, with several publications, in which one of his publications received the Young Author Best Paper Award from the IEEE in 2011. After completing the Ph.D. degree, he briefly worked as a Lecturer in Mechanical Engineering with the University of Peradeniya, Sri Lanka, a Research Fellow with the University of Bradford, U.K., and a Lecturer of Engineering with the Glyndwr University, U.K., before joining the UoM.

He is currently an Assistant Professor with the Faculty of Science and Engineering, School of Materials, University of Manchester (UoM). He is working mainly with the Northwest Composts Centre and the Aerospace Research Institute, and supervising research students affiliated with the School of Materials, UoM, and the School of Mechanical and Aerospace Engineering, UoM. So far, he has authored 45+ peer-reviewed journals/conference papers. Moreover, he has authored a monograph, “Polymer Extrusion: A Study on Thermal Monitoring Techniques and Melting Issues.” His current research interests include: process monitoring, modeling, and control; and soft sensors and soft sensing; process instrumentation; renewable energy technologies; 3D printing, phase change materials; and heat transfer. He is an Associate Member of the professional bodies, including IESL, IMechE, and ICPM; and also a Fellow of the Higher Education Academy, U.K.

Moreover, he is currently an Associate Editor of the Journal of Fluid Flow, Heat and Mass Transfer and Composites Communications. Also, he is serving as a visiting professor of Southwest University, China. He has been served on scientific committees, and he has also been invited for keynote speeches of several international conferences.

Reference

Ogbonnaya, C., Turan, A., & Abeykoon, C. (2019). Numerical integration of solar, electrical and thermal exergies of photovoltaic module: A novel thermophotovoltaic model. Solar Energy, 185, 298-306.

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