Performance improvement of photovoltaic-thermal collector equipped with copper metal foam air channel

ABSTRACT

Avoiding high temperatures in photovoltaic cells with appropriate cooling is necessary to increase their conversion efficiency. Passive cooling systems using metal foam in the air channel were investigated, but an overall assessment is necessary for its viable application. In this numerical study, the thermal, electrical, and exergy efficiencies, as well as the entropy generation of a PVT are analyzed in the presence of copper metal foam in the air channel. The investigation is performed using a CFD code based on the pressure-based finite volume method. The non-Darcy effects of the porous foam are taken into account. Validation of the numerical model is made by comparison of the numerical predictions with experimental results of the literature. The outcomes indicate that varying the porosity from 1 to 0.89 increases the thermal energy, electrical energy, and exergy efficiency from 44.50% to 67.01%, 10.64% to 11.54%, and 12.01% to 13.19%, respectively, while the entropy generation decreases from 1.3116 W/K to 1.2942 W/K. Furthermore, the optimum thickness of the cooling channel is determined (30 cm for 0.93 copper foam porosity).

KEYWORDS:

• Metal foam
• cooling
• exergy
• entropy
• thermal performance
• photovoltaic

Nomenclature

$C_E$	=	Inertial coefficient (1/m)
cp	=	Specific heat (J/kg K)
dl	=	Ligament diameter (m)
dp	=	Pore size (m)
$\dot{E}$	=	Power (W)
$\dot{E}\mathit{x}$	=	Rate of exergy (W)
$\mathit{h}$	=	Heat transfer coefficient
k	=	Turbulence energy ($\mathit{J}/\mathit{kg}$)
K	=	Permeability of porous foam (1/m2)
$\dot{m}$	=	Mass flow rate (kg/s$)$
P	=	Pressure (Pa)
${\dot{S}}_{\mathit{gen}}$	=	Entropy generation (W)
T	=	Temperature (K)
u,v	=	Velocity components (m/s)
x, y	=	Coordinate components (m)
Greek symbols	=
α	=	Absorptivity
Ρ	=	Density(kg/m3)
$\mathit{\epsilon }$	=	Dissipation energy ($1/\mathrm{m}{\mathrm{s}}^3)$
µ	=	Dynamic viscosity (Pa.s)
η	=	Efficiency (%)
g	=	Glass cover transmissivity
ω	=	Pore density (PPI)
$\mathit{\delta }$	=	Porosity
λ	=	Thermal conductivity (W/m.K)
Subscripts	=
a	=	Ambient
e	=	Effective value
el	=	Electrical
f	=	Fluid
g	=	Glass cover
In	=	Inlet
sf	=	Interstitial
out	=	Outer
pv	=	Photovoltaic unit
pf	=	Porous foam
s	=	Solid components
th	=	Thermal
w	=	Wind
Abbreviations	=
HTF	=	Heat transfer fluid
PVT	=	Photovoltaic/thermal system

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Khaoula Nedjem

Khaoula Nedjem is a researcher in the laboratory of mechanics at the University Amar Telidji of Laghouat, Algeria. She has obtained a PhD in thermal engineering. Her research focused on improvement of thermal performance of phase change materials in various applications including heat exchangers and photovoltaic panels. She published in journals of impact in thermal science. The author is interested in heat transfer and thermal engineering.

Ramdani Hamza

Ramdani Hamza is a researcher in thermal engineering. He obtained his PhD in 2022 from University of Guelma, Algeria. He is a fellow of the department of mechanical engineering, Faculty of science and technology, University of Guelma. He worked on nanofluids and their thermal performance in mainly photovoltaic panels. The author is interested in nanofluids, heat transfer and thermal application.

Thiago T. M. Rocha

Thiago T. M. Rocha received the BSc, MSc, and DSc degrees in Mechanical Engineering, in 2015 and 2020, and 2023 respectively, from the Federal University of Minas Gerais (UFMG), Brazil. Currently, he is Adjunct Professor at the Federal University of Minas Gerais. His research interests include thermal engineering and renewable energy, with emphasis on the applications of latent thermal energy storage, energy recovery, refrigeration, heating, and solar energy.

Mohamed Teggar

Mohamed Teggar is a researcher and faculty member in mechanical engineering. He has been working since 2007 at the department of Mechanical Engineering, University Amar Telidji of Laghouat, Algeria. The researcher is a member of the Laboratory of Mechanics (LMe), Renewable Energy team. He graduated from the University of Laghouat, Algeria and obtained his PhD in physics in 2013 from the University of Skikda, Algeria. His research interests include heat transfer, phase change materials, and thermal energy storage. The researcher has authored research and review articles and published in leading journals in thermal engineering field and renewable energy.

Abdelghani Laouer

Abdelghani Laouer is currently working as Professor in the Faculty of Exact Sciences and Computer Science, Department of Physics, University of Jijel, Algeria. Member of the Laboratory of Condensed Matter Physics and Nanomaterials. He received his PhD in Energy Physics in 2017 from Skikda University, Algeria. His research interests are Heat transfer, Computational Fluid Dynamics, Thermal Energy Storage, Nanofluids and Hydrodynamic Stability.

Müslüm Arıcı

Müslüm Arıcı is a faculty member in Mechanical Engineering Department of Kocaeli University, Turkey. He completed Diploma Course at von Karman Institute, Belgium in 2007 and received PhD degree from Kocaeli university in 2010. His research fields of interest are Numerical Heat Transfer, Computational Fluid Dynamics, Thermal management, Thermal Energy Storage, Solar Energy and Nanofluids.

Tahar Tahouari

Tahar Tahouri is a lecturer of physics in the faculty of technology at the university of Laghouat, Algeria. He is also a researcher on thin films and photovoltaics. He is preparing a PhD in the university of Bechar, Algeria, on enhancement of photovoltaics components including thin films. The author’s research interests also include thin films and nanotechnology, material characterization, and semiconductors.