عُتبه ابراهيم العوران

ASUجامعة العلوم التطبيقية الخاصة - الصفحة الرئيسيةكلية الهندسة والتكنولوجياعُتبه ابراهيم العورانالأبحاث

الأبحاث

Recent experimental enhancement techniques applied in the receiver part of the parabolic trough collector–A review

Authors :Otabeh Al-Oran, Ferenc Lezsovits

Abstract :Recently, the thermal performance of the parabolic trough collector (PTC), augmented to be more applicable and efficient, received intensive research. These studies aimed to improve heat transfer in the receiver part, in order to decrease the heat loss, and enhance the heat transfer to the thermal fluid. Many previous review papers focused on the numerical sides rather than the experimental side. Several research papers recommended doing more research in the experimental field; in order to decrease the gap between the numerical and experimental results, as well as increase the confidence level of what has been done in the theoretical field researches. Regarding the recommendations of the recent papers to decrease the gap between numerical and experimental aspects, this review paper focused on the recent experimental research related to thermal enhancement performance in the receiver part of the parabolic solar collector. In this research, different categories of the enhancement methods are discussed in detail through this review, namely nanofluids, surface modifications, and inserts models or the two categories combined together. We discussed these categories for different parabolic troughs considering only the recent experimental research between the period from 2014 up to 2019. Some parameters were discussed, such as the main dimensions of the examined receiver and parabolic collector. Moreover, types of nanoparticle specifications and preparation methods with different base fluids were highlighted. In addition, we discussed different aspects of using inserts models and inlet and outlet surface modification methods. Finally, the main thermal efficiency and thermal performance enhancement results for each work were presented.

Keywords :parabolic trough collector, experimental, thermal performance enhancement, nanofluid

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Exergy and energy amelioration for parabolic trough collector using mono and hybrid nanofluids

Authors : Otabeh Al-Oran, Ferenc Lezsovits & Ayham Aljawabrah

Abstract : Energy and exergy efficiency amelioration of the parabolic trough has taken high interest since recent years, especially when nanofluid used as an enhancement category. This paper aimed to improve LS-2 parabolic trough model and compare the enhancement effect that occurred using different mono and hybrid nanofluids. Inserting mono nanoparticles of Al2O3, CeO2, CuO, and hybrid combinations of Al2O3 with CeO2, or CuO nanoparticles in a Syltherm 800 was investigated by five different cases. The investigation was presented under total volume fraction 4% for all nanofluids and mixing fraction 50:50 for the hybrid types in order to facilitate the analysis and compare various results at the same conditions. Those cases and their comparisons were solved using MATLAB Symbolic tools under turbulent flow regime and variable inlet temperature to present wide domain behavior for the energy and exergy efficiency, Nusselt number, heat transfer coefficient, and pressure drop, whereas the analytical solution of the energy balance equation was taken from the literature and improved to cover the mentioned cases. Moreover, the results were compared with previous researches that used different thermal fluid and showed high accuracy behavior with low deviation. Therefore, the findings showed that Al2O3 and CeO2 hybrid nanofluids were more efficient than using of both Al2O3 and CuO hybrid nanofluids and any mono nanofluids contain the same nanoparticles. The maximum enhancement of thermal and exergy efficiency of using Al2O3 and CeO2 hybrid nanofluids was 1.09% and 1.03%, respectively, whereas it was enhanced by 167.8% and 200.7% for the Nusselt number and heat transfer coefficient, respectively. Also, the hybrid nanofluids have higher advantage over the mono nanofluids by presenting lower pressure drop values. Finally, the assessment of efficiency variation affected by the thermal properties of the nanoparticle was presented under an optimum temperature equal to 575 K.

Keywords :Parabolic trough collector · Thermal performance enhancement · Hybrid nanofluid · Mono nanofluid · Thermal efficiency · Exergy efficiency

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A Hybrid Nanofluid of Alumina and Tungsten Oxide for Performance Enhancement of a Parabolic Trough Collector under the Weather Conditions of Budapest

Authors : Otabeh Al-Oran, Ferenc Lezsovits

Abstract :Recently, there has been significant interest in the thermal performance of parabolic trough collectors. They are capable of operating and generating highly variable temperature ranges, which can be used in various applications. This paper, therefore, addressed the thermal performance model of using a parabolic trough collector under the radiation intensity level found in Budapest city, as well as the effect of inserting a hybrid nanofluid as the thermal fluid. First, a new modified hybrid nanofluid of alumina and tungsten oxide-based Therminol VP1 is used to enhance the thermal properties of the thermal fluid to be more efficient to use. This enhancement is performed under various volume concentrations and has a volume fraction of 50:50. Second, in order to demonstrate the effectiveness of the thermal element, mathematical energy balance equations were solved and simulated using MATLAB Symbolic Tools. The simulation is presented for two cases: one under a constant radiation intensity and the other under the radiation intensity level of Budapest. For both cases, the results of the dimensionless Nusselt number, heat transfer coefficient, pressure drop, exergy efficiency, and energy efficiency are described. The major findings show that a volume concentration of 4% (Al2O3 and WO3) based Therminol VP1 was the most efficient volume concentrations in both cases. For the first case, the maximum enhancement of the Nusselt number and the heat transfer coefficient are 138% and 169%, respectively. These results enhanced the thermal and exergy efficiencies by 0.39% and 0.385% at a temperature 600 K, flow rate of 150 L/min, and radiation intensity of 1000 W/m2. For the second case, the maximum exergy and energy values are recorded at midday under Budapest’s summer climatic conditions and reach 32.728% and 71.255%, respectively, under the optimum temperature of 500 K and flow rate of 150 L/min. Accordingly, the mean improvement in thermal and exergy efficiencies approximately equal to 0.25% at a high concentration, regardless of the season (summer or winter).

Keywords : solar energy; parabolic trough collector; thermal performance enhancement; radiation intensity; hybrid nanofluid; thermal efficiency; Budapest

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Performance analysis and particle swarm optimization of molten salt-based nanofluids in parabolic trough concentrators

Authors :Amr Kaood, Mohamed Abubakr, Otabeh Al-Oran, Muhammed A Hassan

Abstract : Molten salts are typically used as energy storage media in concentrating solar power systems for their lower costs and environmental impact. This study aims to map and optimize the performance of parabolic trough concentrators (PTCs) working with molten salt-based nanofluids (MSNFs) as heat transfer media at high temperatures. The thermal, hydraulic, energetic, and exergetic performances were analyzed and optimized using a unique framework of Monte Carlo optical simulations, computational fluid dynamics, data-drive support vector regression, particle swarm optimization, and decision-making techniques. Three molten salts (Solar Salt, Hitec, and Hitec XL) and three nanoparticle types (Al2O3, CuO, and SiO2) were investigated in a broad range of volumetric concentrations (0.0–4.0%), operating Reynolds numbers (4 × 103 to 40 × 103), and temperatures (535–805 K). The results showed a maximum energy efficiency of 69.1%, achieved when using SiO2-Hitec nanofluid (1.0%) at a Reynolds number of 40 × 104 and temperature of 535 K. The maximum achieved exergy efficiency was 70.48%, obtained using pure Hitec at a Reynolds number of 40 × 104 and temperature of 535 K. The maximum possible enhancements in energy and exergy efficiencies in the covered range are 17.0 and 42.0%, respectively. The optimal combination of energy and exergy efficiencies are ∼73.1 and 69.0%, obtained using CuO-Hitec nanofluid at temperature, Reynolds number, and concentration of 535 K, 39912.98, and 0.019%, respectively. The optimum combination of percentage enhancements in energy and exergy efficiencies are 0.465 and 7.182%, respectively, which corresponds to CuO-Hitec nanofluid operating at 805 K, 32025.4, and 0.092%, respectively.

Keywords : Concentrating solar power Parabolic trough collector Nanofluid, Molten salt, Support vector, machines Particle, swarm optimization.

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Experimental Study of Thermal Conductivity and Viscosity of Water-Based MWCNT-Y2O3 Hybrid Nanofluid with Surfactant

Authors : Otabeh Al-Oran, Ferenc Lezsovits

Abstract : There is an overwhelming demand in many solar applications to evaluate and improve the thermal properties (dynamic viscosity and thermal conductivity) of working fluids to ensure that those fluids are the most efficient. This can be achieved via scattering of tiny solid (mono or hybrid) nanomaterials into conventional fluids. In this experimental study, the thermal properties of a distilled water-based MWCNT+Y2O3 combination with a 20:80 weight ratio were experimentally investigated. The proposed hybrid nanofluid, prepared by a two-step method, with Gum Arabic as a surfactant, had half total volume concentrations of (0.01–0.2% vol) in the temperature range of 20–60°C, where stability has been reached and checked with various technics. The results demonstrate that the thermal conductivity coefficient increases with both temperature and concentration, especially at high concentrations and high temperatures. The maximum enhancement observed reaches 13% at a volume concentration of 0.2% and temperature of 60°C. As for the viscosity, the relative viscosity was obtained for various temperatures and concentrations, the maximum results reaching 8.85 at a concentration equal to 0.2%. Finally, correlations for the hybrid nanofluid thermal conductivity ratio and relative viscosity were suggested under the mentioned limitations, and the calculated experimental results demonstrate good accuracy with the proposed correlations with R2 = 0.99 for the thermal conductivity ratio and R2 = 0.95 for the relative viscosity.

Keywords :

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Thermal conductivity of Al2O3 and CeO2 nanoparticles and their hybrid based water nanofluids: An experimental study

Authors : Mohammed Saad Kamel, Otabeh Al-Oran, Ferenc Lezsovits

Abstract :In many heat exchange systems, there is a demand to improve the thermal conductivity of the working fluids to make those fluids more efficient, and this can be done by dispersing solid nanomaterials into conventional liquids. In the present work, the thermal conductivity of alumina, ceria, and their hybrid with ratio (50: 50) by volume-based deionized water nanofluids was experimentally measured. The nanofluids were prepared by two-step method with a range of dilute volume concentration (0.01-0.5% Vol.), and measured at various temperatures (35, 40, 45, and 50 ºC). The experimental data for basefluid and nanofluids were verified with theoretical and experimental models, and the results have shown good agreement within the accuracy of the thermal conductivity tester. The results demonstrated that the higher thermal conductivity enhancement percentages for Al2O3, CeO2, and their hybrid nanofluids were (5.3%, 3.3%, and 8.8%) at volume concentration (0.5% Vol.) and temperature (50 ºC) compared to deionized water, respectively. Moreover, a correlation was proposed for the thermal conductivity enhancement ratio of the hybrid nanofluid and showed good accuracy with measured experimental data.

Keywords : thermal conductivity; Al2O3 nanoparticles; CeO2 nanoparticles; hybrid nanofluid; experimental study

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Statistical estimation of hourly diffuse radiation intensity of Budapest City.

Authors : Loiy Al‐Ghussain, Otabeh Al‐Oran, Ferenc Lezsovits

Abstract :he vulnerability of fossil fuel prices to worldwide events such as the recent coronavirus (COVID-19) pandemics increases the interest in renewable energy resources that offer more stable energy generation costs. Solar energy is one of the most abundant renewable energy resources that have gained significant interest in the last decades with various challenges related to the forecastingof the energy production from these systems. Solar radiation intensity varies due to the daily and seasonal changes in the sun's position in addition to the variation in the sky clearness from one location to another which is considered as an important factor that affects the deployment of solar energy systems. This study aims to develop statistical models—mainly regression models and parametric model based on ASHRAE model—to estimate the hourly diffuse radiation in Budapest as a case study using the measured hourly global and diffuse radiation between 2011 and 2018. The prediction models relate the clearness index (which is obtained from the extraterrestrial and global radiation) and the global radiation through a generalized equation. The parametric model was developed by finding the optimal site-specific constants of ASHRAE model for Budapest using the measured data that minimize the root mean square error. In addition, this study presents a comparison between the results from the developed models and the models reported in the literature. The results indicate that all the developed regression models had close correlation coefficients (R2) where the linear, power, and exponential models had the largest R2 (.69). Finally, the linear model was evaluated on a dataset outside the test data range where the linear model was capable of predicting the diffuse radiation with much better R2 (.93).

Keywords :radiation intensity, renewable energy in COVID-19 era, solar energy, solar resource forecasting, statistical model

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