The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Josua P Meyer - One of the best experts on this subject based on the ideXlab platform.
-
numerical analysis of the thermal and thermodynamic performance of a parabolic trough solar collector using swcnts Therminol vp 1 nanofluid
Renewable Energy, 2018Co-Authors: Aggrey Mwesigye, Ibrahim Halil Yilmaz, Josua P MeyerAbstract:Abstract In this paper, energetic and exergetic performances of a parabolic trough solar collector using single-walled carbon nanotubes (SWCNTs)-Therminol® VP-1 nanofluid were numerically investigated and presented. The main objective of this investigation was to determine the influence of high thermal conductivity SWCNTs suspended in the widely used heat transfer fluid, Therminol®VP-1 on the performance indicators of the parabolic trough solar collector. A parabolic trough system with a high concentration ratio of 113 was analyzed in this study. The thermo-physical properties of SWCNTs were taken as functions of nanotube length, nanotube diameter, and temperature, while the properties of Therminol®VP-1 were considered to be temperature dependent. The study involved determination of the actual heat flux profile through Monte Carlo ray tracing and the subsequent coupling of this heat flux profile to a computational fluid dynamics tool using user defined functions. The computational fluid dynamics tool was finite volume based, and the realizable k-e model together with enhanced wall treatment were used for turbulence modeling. The entropy generation rates were obtained directly from the local velocity and temperature fields of the computed domain and later used in the exergy analysis. Results showed that although the heat transfer performance significantly improved with the use of SWCNTs, the increase in the thermal efficiency was not substantial. For the considered range of parameters, while the heat transfer performance increased up to 234%, the thermal efficiency increased around 4.4% as the volume fraction increased from 0 to 2.5%. The corresponding reduction in the entropy generation was about 70%.
-
thermal performance and entropy generation analysis of a high concentration ratio parabolic trough solar collector with cu Therminol vp 1 nanofluid
Energy Conversion and Management, 2016Co-Authors: Aggrey Mwesigye, Zhongjie Huan, Josua P MeyerAbstract:National Research Foundation (NRF), the Translational Engineering Skills Programme (TESP), Stellenbosch University, the South African National Energy Research Institute (SANERI)/South African National Energy Development Institute (SANEDI) at the University of Pretoria, the Council for Scientific and Industrial Research (CSIR), the Energy-efficiency and Demand-side Management (EEDSM) Hub and NAC.
K S Reddy - One of the best experts on this subject based on the ideXlab platform.
-
investigation of solar parabolic trough power plants with and without integrated tes thermal energy storage and fbs fuel backup system using thermic oil and solar salt
Energy, 2015Co-Authors: T E Boukelia, Bohra Nitin Kumar, K S ReddyAbstract:Thermodynamic, economic and environmental analyses of concentrating solar power plants assist in identifying an effective and viable configuration. In this paper, a 4E (energy-exergy-environmental-economic) comparative study of 8 different configurations of parabolic trough solar thermal power plants with two different working fluids (Therminol VP-1 -oil and molten solar salt), with and without integrated thermal energy storage or/and backup fuel system is presented. The results of the comparative study indicate relevant differences among the 8 configurations. The molten solar salt configuration with integrated thermal energy storage and fossil fuel backup system exhibits the highest overall energy efficiency (18.48%) compared to other configurations. Whereas, the highest overall exergy efficiency (21.77%), capacity factor (38.20%) and annual energy generation (114 GWh) are found for the oil based configuration with integrated thermal energy storage and fossil fuel backup system. The results indicate that the configurations based on molten salt are better in terms of environmental and economical parameters. The configurations with integrated thermal energy storage and fossil fuel backup system are found to be techno-economical, but on the other hand are less environment friendly. A detailed comparison of these plants after optimization must be performed before drawing a final conclusion about the best configuration to be adopted in parabolic trough solar thermal power plant.
-
Optimization, selection and feasibility study of solar parabolic trough power plants for Algerian conditions
Energy Conversion and Management, 2015Co-Authors: T E Boukelia, Bohra Nitin Kumar, M.s. Mecibah, K S ReddyAbstract:Abstract In the present study, optimization of two parabolic trough solar thermal power plants integrated with thermal energy storage (TES), and fuel backup system (FBS) has been performed. The first plant uses Therminol VP-1 as heat transfer fluid in the solar field and the second plant uses molten salt. The optimization is carried out with solar multiple (SM) and full load hours of TES as the parameters, with an objective of minimizing the levelized cost of electricity (LCOE) and maximizing the annual energy yield. A 4E (energy–exergy–environment–economic) comparison of the optimized plants alongside the Andasol 1 as reference plant is studied. The molten salt plant resulting as the best technology, from the optimization and 4E comparative study has been chosen for the viability analysis of ten locations in Algeria with semi-arid and arid climatic conditions. The results indicate that Andasol 1 reference plant has the highest mean annual energy efficiency (17.25%) and exergy efficiency (23.30%). Whereas, the highest capacity factor (54.60%) and power generation (236.90 GW h) are exhibited by the molten salt plant. The molten salt plant has least annual water usage of about 800,482 m 3 , but demands more land for the operation. Nevertheless the oil plant emits the lowest amount of CO 2 gas (less than 40.3 kilo tonnes). From the economic viewpoint, molten salt seems to be the best technology compared to other plants due to its lowest investment cost (less than 360 million dollars) and lower levelized cost of electricity (LCOE) (8.48 ¢/kW h). The viability study proposes Tamanrasset, as the best location for erection of a parabolic trough solar thermal power plant with a low LCOE of 7.55 ¢/kW h, and a high annual power generation (more than 266 GW h). According to the feasibility analysis, the semi-arid and arid Algerian sites are suitable for realization of PTSTPP with integrated TES and FBS; especially the southern locations (19°N–32°N, 8°W–12°E).
Aggrey Mwesigye - One of the best experts on this subject based on the ideXlab platform.
-
Thermal and thermodynamic benchmarking of liquid heat transfer fluids in a high concentration ratio parabolic trough solar collector system
Journal of Molecular Liquids, 2020Co-Authors: Aggrey Mwesigye, Ibrahim Halil YilmazAbstract:Abstract The thermal oil-based heat transfer fluids (HTFs) used in parabolic trough solar collector (PTSC) systems suffer from degradation at temperatures above 400 °C, limiting the thermal efficiencies of these systems. As such, several researchers have investigated various HTFs for high-temperature applications of PTSCs. In this study, the thermal and thermodynamic performance of a PTSC system with a geometrical concentration ratio of 113 is numerically investigated. The developed and thorough validated numerical model combines Monte-Carlo ray tracing and computational fluid dynamics for optical analysis, and thermal and thermodynamic studies, respectively. Ten HTFs with temperature-dependent thermal physical properties are considered. They are –Liquid metals: liquid sodium, Lead-Bismuth Eutectic (LBE), –Molten salts: Solar Salt, Hitec, Hitec XL, a ternary salt mixture: LiNO3 + NaNO3 + KNO3 (18 wt%, 52 wt%, and 30 wt%), a quaternary salt mixture: NaNO3 + KNO3 + LiNO3 + Ca(NO3)2 (9 wt%, 54 wt%, 18 wt%, and 18 wt%), a new salt mixture: NaCl+KCl + ZnCl2 (7.5 wt%, 23.9 wt%, and 68.6 wt%), and –Thermal oils: Therminol VP-1 and Dowtherm A. Results show that liquid sodium gives the best thermal, hydraulic, and thermodynamic performance of the considered HTFs at all flow rates and inlet temperatures. LBE gives the second highest heat transfer performance, however, its thermal and thermodynamic performance degrade as flow rates increase above 32.75 m3/h owing to the high pumping power and fluid flow irreversibilities. As liquid sodium and LBE are expensive, LiNO3 + NaNO3 + KNO3 (18 wt%, 52 wt%, and 30 wt%) shows better overall performance as compared with other molten salts. Moreover, it possesses a low melting point and high thermal stability temperature. In addition, the thermal efficiency is within ±0.4% for molten salts at flow rates between 16 and 36 m3/h that give optimal performance.
-
numerical analysis of the thermal and thermodynamic performance of a parabolic trough solar collector using swcnts Therminol vp 1 nanofluid
Renewable Energy, 2018Co-Authors: Aggrey Mwesigye, Ibrahim Halil Yilmaz, Josua P MeyerAbstract:Abstract In this paper, energetic and exergetic performances of a parabolic trough solar collector using single-walled carbon nanotubes (SWCNTs)-Therminol® VP-1 nanofluid were numerically investigated and presented. The main objective of this investigation was to determine the influence of high thermal conductivity SWCNTs suspended in the widely used heat transfer fluid, Therminol®VP-1 on the performance indicators of the parabolic trough solar collector. A parabolic trough system with a high concentration ratio of 113 was analyzed in this study. The thermo-physical properties of SWCNTs were taken as functions of nanotube length, nanotube diameter, and temperature, while the properties of Therminol®VP-1 were considered to be temperature dependent. The study involved determination of the actual heat flux profile through Monte Carlo ray tracing and the subsequent coupling of this heat flux profile to a computational fluid dynamics tool using user defined functions. The computational fluid dynamics tool was finite volume based, and the realizable k-e model together with enhanced wall treatment were used for turbulence modeling. The entropy generation rates were obtained directly from the local velocity and temperature fields of the computed domain and later used in the exergy analysis. Results showed that although the heat transfer performance significantly improved with the use of SWCNTs, the increase in the thermal efficiency was not substantial. For the considered range of parameters, while the heat transfer performance increased up to 234%, the thermal efficiency increased around 4.4% as the volume fraction increased from 0 to 2.5%. The corresponding reduction in the entropy generation was about 70%.
-
thermal performance and entropy generation analysis of a high concentration ratio parabolic trough solar collector with cu Therminol vp 1 nanofluid
Energy Conversion and Management, 2016Co-Authors: Aggrey Mwesigye, Zhongjie Huan, Josua P MeyerAbstract:National Research Foundation (NRF), the Translational Engineering Skills Programme (TESP), Stellenbosch University, the South African National Energy Research Institute (SANERI)/South African National Energy Development Institute (SANEDI) at the University of Pretoria, the Council for Scientific and Industrial Research (CSIR), the Energy-efficiency and Demand-side Management (EEDSM) Hub and NAC.
Mostafa M. Abd El-samie - One of the best experts on this subject based on the ideXlab platform.
-
A fully coupled numerical simulation of a hybrid concentrated photovoltaic/thermal system that employs a Therminol VP-1 based nanofluid as a spectral beam filter
Applied Energy, 2020Co-Authors: Mostafa M. Abd El-samie, Yu Hangyu, Xinyu Pan, Yongping YangAbstract:The realistic numerical modelling of multiphysics applications is an efficient way to precisely predict the operation of concentrated solar systems. Although many multiphysics conjugating approaches have been proposed in the literature, it is difficult to adopt such methods into simulating complex concentrated solar technologies. Consequently, this study introduces a novel 2D:3D numerical optical, thermal and electric coupling approach for a hybrid compound parabolic concentrator photovoltaic/thermal (CPC-PV/T) collector using a nanofluid as a spectral beam filter. In this approach, the volumetric absorbed radiation in each component of the system obtained from the non-gray 2D model is patched into the 3D model as a volumetric heat source using sophisticated computational tools. The main features of the full coupling method (FCM) are extensively analyzed and compared with the other two coupling methods previously adopted. Further, the module performance has been investigated employing both the nanofluid and base-fluid spectrum filters (BF-filter) compared with a stand-alone concentrated PV cell. From findings, the FCM can be applied to reveal more realistic operation characteristics of the proposed system compared with the other approaches, since the FCM can take into account the non-uniformity of solar illumination and the direction of reflected solar beams upon the receiver, along with the variation in the optical characteristics of utilized materials over the solar irradiance. Additionally, suspending indium tin oxide (ITO) nanoparticles into the Therminol VP1 oil raises the absorption rate over the thermal-bands with 62.5% higher than the use of BF-filter, whilst the cell temperature and the transmitted irradiance within the PV-band are obviously declined.
-
Three-dimensional numerical investigation of a hybrid low concentrated photovoltaic/thermal system
Energy, 2020Co-Authors: Mostafa M. Abd El-samie, Zheyang Zhang, Saadelnour Abdueljabbar Adam, Xinyu PanAbstract:Abstract Concentrated photovoltaic/thermal hybrid collectors have received ever-increasing attention due to the simultaneous output of electric and thermal energy. For further improvement of concentrated hybrid PV/T systems, a simulation method combining the multiphysics fields is necessary to accurately analyze the optical, thermal, and electric performance. Herein, a three-dimensional numerical study has been conducted on a low concentrated photovoltaic/thermal system utilizing a heat transfer fluid as the cooling medium and a compound parabolic concentrator as the mirror field. A finite volume (FV)-CFD code has been employed to simulate the entire model, where the optical modelling is validated theoretically with the Monte Carlo ray-tracing method. The influences of employing various heatsink designs (U-type and Z-type) and coolants (water, ethylene glycol, and Therminol VP-1) are numerically investigated. The economic feasibility of the hybrid PV/T system is also assessed in comparison with the standalone PV-cell. Good compatibility with the empirical data was obtained when the appropriate modelling tunings were applied. It is also shown that, on a typical day, the total energy and exergy efficiencies of the system are up to 57.66% and 7.94%, respectively. The Z-type heatsink decreases the average PV-cell temperature than the U-type design, and also the output power is slightly enhanced.
-
Numerical study of a photovoltaic/thermal hybrid system with nanofluid based spectral beam filters
Energy Conversion and Management, 2018Co-Authors: Mostafa M. Abd El-samie, Qunzhi ZhuAbstract:Abstract This study presents a 3-dimensional numerical simulation of a flat-plate photovoltaic/thermal (PV/T) hybrid system using a nanofluid as the solar spectrum filter. A series of parametric studies have been carried out to investigate the module performance by employing different base fluid (water, Therminol VP-1 and propylene glycol) - nanoparticle (Ag, Fe3O4 and SiO2) combinations. The present work explores the effects of different nanoparticle concentrations, volume flow rates of applied nanofluids, as well as the solar spectrum intensities on the energetic and exergetic performances of the proposed module. Merit functions for various basefluid or nanofluid based hybrid PV/T systems are also assessed in order to determine their economic feasibility. The results show that the suspension of nanoparticles into basefluids has a considerable influence on the radiative heat fluxes that are absorbed by each component of such system. The selection of basefluid-nanoparticle combination is dramatically affected by the desired energy form, based on the system energetic and exergetic performances. Besides, both the system energy and exergy efficiencies are improved with the increment of solar irradiance, whereas they have a counter tendency by increasing the volume flow rate of working fluid. The employment of liquid absorptive filters in such systems can realize a higher energy output which is 179%–240% of that of a stand-alone PV system.
Yongping Yang - One of the best experts on this subject based on the ideXlab platform.
-
A fully coupled numerical simulation of a hybrid concentrated photovoltaic/thermal system that employs a Therminol VP-1 based nanofluid as a spectral beam filter
Applied Energy, 2020Co-Authors: Mostafa M. Abd El-samie, Yu Hangyu, Xinyu Pan, Yongping YangAbstract:The realistic numerical modelling of multiphysics applications is an efficient way to precisely predict the operation of concentrated solar systems. Although many multiphysics conjugating approaches have been proposed in the literature, it is difficult to adopt such methods into simulating complex concentrated solar technologies. Consequently, this study introduces a novel 2D:3D numerical optical, thermal and electric coupling approach for a hybrid compound parabolic concentrator photovoltaic/thermal (CPC-PV/T) collector using a nanofluid as a spectral beam filter. In this approach, the volumetric absorbed radiation in each component of the system obtained from the non-gray 2D model is patched into the 3D model as a volumetric heat source using sophisticated computational tools. The main features of the full coupling method (FCM) are extensively analyzed and compared with the other two coupling methods previously adopted. Further, the module performance has been investigated employing both the nanofluid and base-fluid spectrum filters (BF-filter) compared with a stand-alone concentrated PV cell. From findings, the FCM can be applied to reveal more realistic operation characteristics of the proposed system compared with the other approaches, since the FCM can take into account the non-uniformity of solar illumination and the direction of reflected solar beams upon the receiver, along with the variation in the optical characteristics of utilized materials over the solar irradiance. Additionally, suspending indium tin oxide (ITO) nanoparticles into the Therminol VP1 oil raises the absorption rate over the thermal-bands with 62.5% higher than the use of BF-filter, whilst the cell temperature and the transmitted irradiance within the PV-band are obviously declined.