The role of climatic-design-operational parameters on combined PV/T collector performance: a critical review

PV/T technology attracted numerous researchers and professionals during the last decades. There are many review papers in the literature evaluated the R&D aspects of PV/T collectors. In fact, there are abundant of case studies discussed the parameters of climate, design and operational conditions affected the PV/T collector performance. But, a comprehensive compilation of the information of those case studies is still a missing link in the literature. Hence, this paper intended to review thoroughly the information regarding the parameters affecting the PV/T collector performance mainly and PV module performance partially. The parameters are supported with the most available R&D to measure the accurate influence of each parameter on the performance. The outcomes from the study are highlighted in lessons learned section

Numerical simulation and experimental study of new design of PV/T as desalination units

Other researchers have examined alternative methods for desalinating water in arid regions, focusing specifically on the utilization of solar energy due to its abundance and lack of negative environmental impact. Desalination is one of the many applications of solar energy, and this study proposes a novel approach that employs solar radiation to evaporate brackish and saltwater. By harnessing the heat generated by incident solar radiation on photovoltaic panels, water is able to evaporate under-controlled conditions. This paper is divided into two main sections: the first involves conducting experiments in the laboratory of Najaf Engineering Technical College, while the second entails the numerical simulation of proposed models using COMSOL Multiphysics V. 6.1 software. Previous research has demonstrated the use of heat produced on the back surface of solar cells to generate distilled water by passing non-potable water through a cotton wick attached to the back surface. The new design of the solar active photovoltaic distiller incorporates a solar photovoltaic, wick, and Peltier device. In this study, the Peltier device was employed to enhance the evaporation and condensation processes, resulting in a solar still that integrates the distillation system with the solar panel, thereby increasing productivity per unit area. The experimental and numerical results indicate that model 02 achieves a productivity of 0.827 kg/m2 h, and 0.907 kg/m2 h for flow rates of 2 mL/min and 4 mL/min, respectively. Model 02, which incorporates a Peltier device within a glass container, demonstrates higher productivity across all experimental days, with a maximum daily cumulative productivity of 4355.3 g. Furthermore, model 02 exhibits higher temperatures compared to other modules, with a maximum average back sheet temperature of 78°C in March and a minimum of 55°C.</p

A review study on the effect of glass envelope, working fluid and geometry contributions for the receiver on performance of parabolic trough collector (PTC)

Renewable energy resources play an essential role in the sustainable energy development as they are friendly energy resources. Solar energy is one of the renewable energy sources are used in many fields from domestic/industrial fluid heating, cooking and electricity production. The parabolic trough collector (PTC) is adopted to be the good choice for medium temperature (150-400 °C) heat necessities. The admiration of solar PTC has generated utility in maximum efficiency energy potential. The heat transfer element (HTE) receiver portion of PTC is the main part in PTC assembly manufactured as tubular shape either without glass envelope or covered with a glass envelope to reduce the radiative and convective heat losses. This article focused on the main parameters was considered in the HTE receiver design of parabolic trough solar collectors (PTC) which were enhanced the heat transfer process in deep details. Further, this work extended to discuss the primary results that came from a different design of PTC receiver based on previous studies in order to benefits researchers who are interested in solar energy collectors. © 2006-2018 Asian Research Publishing Network (ARPN)

Enhancement heat transfer characteristics in the channel with Trapezoidal rib–groove using nanofluids

Numerical study of heat transfer due to turbulent flow of nanofluids through rib–groove channel have been investigated. The continuity, momentum and energy equations are solved by the finite volume method (FVM). Four different rib–groove shapes have been examined. Four different types of nanoparticles, Al2O3, CuO, SiO2, and ZnO with different volumes fractions in the range of 1–4% and different nanoparticle diameter in the range of 25–70 nm, have been also studied. The computations are performed under constant temperature over a range of Reynolds number (Re) 10,000–40,000. Results indicate that the Trapezoidal with increasing height in the flow direction rib–trapezoidal groove has the best heat transfer rate and high Nusselt number. It is also found that the SiO2 – nanofluid has the highest value of Nusselt number in comparison with the other type of nanofluids. The Nusselt number increases as the volume fraction increases and it decreases as the nanoparticle diameter increases. The present study shows that these Trapezoidal rib–groove using nanofluids have the potential to dramatically increase heat transfer characteristics and thus can be good candidates for the development of efficient heat exchanger device

Enhance heat transfer in the channel with V-shaped wavy lower plate using liquid nanofluids

The heat transfer and flow characteristics in corrugated with V-shape lower plate using nanofluids are numerically studied. The computations are performed on uniform heat flux over a range of Reynolds number (Re) 8000–20,000. The governing equations are numerically solved in the domain by a finite volume method (FVM) using the k–ε standard turbulent model. Studies are carried out for different types of nanoparticles Al2O3,CuO, SiO2 and ZnO with different volume fractions in the range of 0–4%. Three different types of base fluid (water, glycerin, ethylene glycol) are also examined. Results indicated that the average Nusselt number for nanofluids is greater than that of the base liquid. The SiO2 nanofluid yields the best heat transfer enhancement among all other type of nanofluids. Heat transfer enhancement increase with increases the volumetric concentration, but it is accompanied by increasing pressure drop values. Moreover, the average Nusselt number increases with an increase in Reynolds number and volume concentration. The SiO2–glycerin nanofluid has the highest Nusselt number compared with other base fluids. The present study shows that these V-shaped wavy channels have advantages by using nanofluids and thus serve as promising candidates for incorporation into efficient heat transfer devices

Design characteristics of corrugated trapezoidal plate heat exchangers using nanofluids

In this paper, fully developed turbulent flow and heat transfer behavior in trapezoidal channels using nanofluids are numerically studied. This study evaluates the effects of four different types of nanoparticles, Al2O3, CuO, SiO2 and ZnO, with different volume fractions (0-4%) and diameters (20-80nm) under constant heat flux (6kW/m2). The effects of geometrical parameters (wavy amplitudes, longitudinal pitch) of the trapezoidal channel on the thermal and flow fields are also examined. The results indicated that SiO2 has the highest Nusselt number among the nanofluids. Enhancement of heat transfer increases with particle volume concentration, but a slight increase in pressure loss with decreasing nanoparticle diameter is also observed. When nanofluids are used in a forced convection, 10% increase in average Nusselt number is observed for nanoparticles with a diameter of 20nm and at 4vol.%. Analysis of the flow and heat transfer in a corrugated trapezoidal channel is made based on the comprehensive evaluation factor J/f. The optimum (J/f) enhancement shows that the CuO nanofluid, lower concentration ratio of nanoparticles, trapezoidal height of 2.5mm and a longitudinal pitch of 6mm are the most desirable parameters for saving energy. Using nanofluids with a corrugated channel can improve the thermal performance because it can lead to more compact heat exchangers