ramdani hamza | Université 8 Mai 1945 Guelma

Thanks to the absorption properties of solar radiation by water, allowing only its effective part (the visible one) to pass, a new geometric and technological configuration of the hybrid PV/T (photovoltaic/thermal) collector based water or nanofluid (TiO2-water) is proposed. It was decided to install the cooling channel not below the PV panel as it is the case in almost all previous studies, but rather at the top of the PV cells, allowing the direct radiation of the visible spectrum to reach their surface. This fact, will avoid the infrared radiation to create an overheating of the PV cells and therefore to decrease the electrical efficiency.

The modeling of such a system is made possible through the consideration of some assumptions, and the obtained results give insight on the thermal and electrical efficiencies. The influences of different parameters (solar radiation, Reynolds number and ambient temperature) are discussed.

The results of the simulations highlight certain facts and observations that deserve some attention, which the most important being that no improvement in heat transfer and efficiency is obtained with the nanofluid considered in this study (TiO2-water) as compared to water.

Abstract (Ar)

Abstract (Ar):

بفضل خصائص امتصاص الإشعاع الشمسي بواسطة الماء ، مما يسمح فقط بتمرير جزءه الفعال (الجزء المرئي) ، تكوين هندسي وتكنولوجي جديد لمياه تجميع الطاقة الكهروضوئية / الكهروضوئية الهجينة أو المياه النانوية (TiO2- ماء) ) هو المقترح. تقرر تثبيت قناة التبريد ليس أسفل اللوحة الكهروضوئية كما هو الحال في جميع الدراسات السابقة تقريبًا ، ولكن في الجزء العلوي من الخلايا الكهروضوئية ، مما يسمح للإشعاع المباشر للطيف المرئي بالوصول إلى سطحها. هذه الحقيقة ، سوف تتجنب إشعاع الأشعة تحت الحمراء لإنشاء ارتفاع في درجة حرارة الخلايا الكهروضوئية وبالتالي تقليل الكفاءة الكهربائية.

يتم نمذجة مثل هذا النظام من خلال النظر في بعض الافتراضات ، والنتائج التي تم الحصول عليها تعطي نظرة ثاقبة على الكفاءة الحرارية والكهربائية. وتناقش تأثيرات المعلمات المختلفة (الإشعاع الشمسي ، رقم رينولدز ودرجة الحرارة المحيطة).

تبرز نتائج عمليات المحاكاة بعض الحقائق والملاحظات التي تستحق بعض الاهتمام ، والتي من أهمها عدم حدوث أي تحسن في نقل الحرارة وكفاءتها باستخدام مادة النانو فلويد التي تم بحثها في هذه الدراسة (TiO2-water) بالمقارنة مع الماء.

Abstract (Fr)

Abstract (Fr):

Grâce aux propriétés d’absorption du rayonnement solaire par l’eau ne laissant passer que sa partie effective (la partie visible), une nouvelle configuration géométrique et technologique de l’eau à base de collecteur hybride PV / T (photovoltaïque / thermique) ou nanofluide (eau TiO2) ) est proposé. Il a été décidé d'installer le canal de refroidissement non pas sous le panneau PV, comme c'était le cas dans presque toutes les études précédentes, mais plutôt au sommet des cellules PV, permettant ainsi au rayonnement direct du spectre visible d'atteindre leur surface. Ceci évitera le rayonnement infrarouge pour créer une surchauffe des cellules PV et donc pour diminuer le rendement électrique.

La modélisation d'un tel système est rendue possible par la prise en compte de certaines hypothèses et les résultats obtenus donnent un aperçu des rendements thermique et électrique. Les influences de différents paramètres (rayonnement solaire, nombre de Reynolds et température ambiante) sont discutées.

Les résultats des simulations mettent en évidence certains faits et observations qui méritent une attention particulière, le plus important étant qu'aucune amélioration du transfert de chaleur et de l'efficacité n'est obtenue avec le nanofluide considéré dans cette étude (TiO2-eau) par rapport à l'eau.

Scientific publications

Scientific publications :

1- Hamza Ramdani, Cherif Ould-Lahoucine,
Study on the overall energy and exergy performances of a novel water-based hybrid photovoltaic-thermal solar collector,
Energy Conversion and Management,
Volume 222,
2020,
113238,
ISSN 0196-8904,
https://doi.org/10.1016/j.enconman.2020.113238.
(https://www.sciencedirect.com/science/article/pii/S0196890420307822)
Abstract: In this work, a novel conceptual water-based hybrid photovoltaic thermal collector design was modeled and numerically simulated using ANSYS Fluent software. The novelty concerns to superimpose a layer of water to the PV module; it will serve to cool the PV cells and also to filter the incoming solar radiation. Water as a natural filter will absorb IR radiations, therefore, it collects thermal energy, besides, it will let the visible radiation pass, reach the PV and generates electricity. Based on the first and second laws of thermodynamics, an analysis of the overall efficiency of the novel hybrid water-based-PVT is performed. The simulations concern the impacts of intrinsic parameters (the height of the cooling channel and water inlet velocity) and extrinsic parameters (the wind velocity, solar irradiation, and the ambient temperature) on the overall energetic and exergetic performances of the PVT. The results show that in terms of energy quantity and quality, the new proposed PVT is superior to previously proposed ones. In addition, a new method to determine the optimal height of the rectangular channel is also proposed and validated.
Keywords: Hybrid PV/T collector; Efficiency and exergy analyses, Spectral absorption; 3D numerical simulation; Rectangular flow channel; Channel optimal height

2- Cherif Ould-Lahoucine, Hamza Ramdani, Driss Zied,
Energy and exergy performances of a TiO2-water nanofluid-based hybrid photovoltaic/thermal collector and a proposed new method to determine the optimal height of the rectangular cooling channel,
Solar Energy,
Volume 221,
2021,
Pages 292-306,
ISSN 0038-092X,
https://doi.org/10.1016/j.solener.2021.04.027.
(https://www.sciencedirect.com/science/article/pii/S0038092X21003145)
Abstract: An energetic and exergetic analysis of a hybrid photovoltaic-thermal solar collector (PV/T) with a rectangular channel through which a water-TiO2 nanofluid circulates is made. A three-dimensional model with the actual boundary conditions of the hybrid collector is simulated under ANSYS Fluent. The results of the simulations are presented in the form of figures and tables with, among other parameters, the overall energetic η (%) and exergetic efficiencies ε (%), thermal and electrical efficiencies, exergetic losses due to heat transfer and friction, as well as the entropy generation in the system. A comparison of the hybrid (PV/T) with a rectangular channel to that with absorber (sheet-and-tube type) shows from the 1st and 2nd laws of thermodynamics perspectives different performances. Among the obtained results, the water-TiO2 based-(PV/T) hybrid collector presents no substantial advantage over the water-based (PV/T). Besides, to determine the height of the heat exchanger with a rectangular cross-section, a novel method is proposed and fully-explained. The obtained value corresponds to the point of inflection of the curve (η(%)–ε(%)) vs. H, and for the case study, it is found to be similar (1.1% difference) to that calculated using the Bejan and Sciubba (1992) formula.
Keywords: Photovoltaic-thermal collector; Water-TiO2 nanofluid; Correlations; Energy and exergy analysis; Optimal height of the cooling channel

Scientific conferences

Scientific conferences:

Ramdani hamza, Cherif ould lahocine, Kidouchi hichem ''Modelling of a hybrid photovoltaic/ thermal Zno-water nanofluide base collector''4TH INTERNATIONAL CONFERENCE ON ADVANCES IN MECHANICAL ENGINEERING ISTANBUUL 2018 DECEMBER 19-11,2018