scholarly journals The Impact of Tilt Angle and Flowrate on Performance of Nanofluid Based Photovoltaic/ Thermal (PV/T) Solar Collectors

2020 ◽  
Author(s):  
Aliasghar Naderi ◽  
Heshmatollah Gazori ◽  
Mahan Bozegi
Keyword(s):  
Tilt Angle ◽  
Solar Collector ◽  
Electrical Energy ◽  
Working Fluid ◽  
Solar Collectors ◽  
Step Method ◽  
Novel Approach ◽  
The Stability ◽  
The Impact ◽  
Global Population

Abstract Background Today, by the arrival of new sustainable energy technology, the provision of energy for the global population has turned into a significant issue for societies. Meanwhile, photovoltaic/thermal (PV/T) solar collectors, as one of the most advanced types to produce electricity and heat simultaneously, can be applied with nanofluid as the working fluid. Methods In this research, PVP coated silver nanofluid was prepared in three volume concentrations being 250, 500 and 1000 ppm by two-step method to determine the stability and thermal conductivity, experimentally. Then, the performance of PV/T solar collector is analyzed by TRNSYS software to study electrical and thermal efficiency and also output electrical and thermal energy in different months, flowrates (25, 50, 75, 100, 150 and 200 l/h) and nanofluid’s concentration. Results Based on the results, the optimum flowrate and nanofluid’s concentration are obtained 50 l/h and 1000 ppm PVP coated silver nanofluid. At last, the effect of tilt angle on the output thermal and electrical energy is determined. According to the results, by changing tilt angle in different months, the performance of PV/T solar collector can be ameliorated. Conclusion This paper can be heeded as a novel approach to overcome the lack of solar radiation in winters by improving the performance of PV/T solar collectors.

Investigating the Effect of Al2O3/Water Nanofluid on the Efficiency of a Thermosyphon Flat-Plate Solar Collector

2016 ◽  
Author(s):  
Mohamed Nabeel A. Negm ◽  
Ahmed A. Abdel-Rehim ◽  
Ahmed A. A. Attia
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Fossil Fuels ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Green Energy ◽  
Working Fluid ◽  
Steady Increase ◽  
Solar Collectors ◽  
Flat Plate Solar Collector

The world is still dependent on fossil fuels as a continuous and stable energy source, but rising concerns for depletion of these fuels and the steady increase in demand for clean “green” energy have led to the rapid growth of the renewable energy field. As one of the most available energy sources with high energy conversion efficiency, solar energy is the most prominent of these energies as it also has the least effect on the environment. Flat plate collectors are the most common solar collectors, while their efficiency is limited by their absorber’s effectiveness in energy absorption and the transfer of this energy to the working fluid. The efficiency of flat plate solar collectors can be increased by using nanofluids as the working fluid. Nanofluids are a relatively recent development which can greatly enhance the thermophysical properties of working fluids. In the present study, the effect of using Al2O3/Water nanofluid as the working fluid on the efficiency of a thermosyphon flat-plate solar collector was experimentally investigated. The results of this experiment show an increase in efficiency when using nanofluids as the working fluid compared to distilled water. It was found that Al2O3/water nanofluids are a viable enhancement for the efficiency of flat-plate solar collectors.

Modeling Software Patch Management Based on Vulnerabilities Discovered

2019 ◽  
Vol 27 (02) ◽  
pp. 2040003 ◽  
Author(s):  
Adarsh Anand ◽  
Navneet Bhatt ◽  
Deepti Aggrawal
Keyword(s):  
Real Life ◽  
Integrative Approach ◽  
Software System ◽  
System A ◽  
Novel Approach ◽  
Time Period ◽  
Modeling Software ◽  
Vulnerability Discovery ◽  
The Stability ◽  
The Impact

A software system deals with various security implications after its release in the market. Correspondingly, firm releases security patches to counter those flaws discovered in the software system. A vendor releases a patch only if a vulnerability has been discovered in a software. It is an important aspect that encompasses the prediction of potential number of patches to be released to maintain the stability of a software. Vulnerability Discovery Models (VDMs) help a software vendor to acknowledge the security trends, forecast security investments and to plan patches, but very few attempts have been made to model the Vulnerability Patch Modeling (VPM) based on the impact of vulnerabilities discovered over the time period. In this proposal, we deduce a novel approach that addresses trend in the sequential development of patches based on the vendor or reporters fetching out the vulnerabilities in a software. The vulnerability trends in a software significantly affect the discovery process and later trigger a patch deployment to suppress the possible likelihood of a breach. The integrative approach underlines the association of vulnerability patch modeling with the vulnerability discovery phenomenon. To exemplify the proposed systematic structure, a statistical analysis has been conducted using real life vulnerability and patch datasets.

scholarly journals Analysis of the Solar Collectors Installation on a Roof of the Small Public Building in Poland, Lithuania and Spain—A Case Study

Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1272 ◽  
Author(s):  
Dorota Anna Krawczyk ◽  
Mirosław Żukowski ◽  
Antonio Rodero ◽  
Ruta Bilinskiene
Keyword(s):  
Solar Radiation ◽  
Tilt Angle ◽  
Solar Collector ◽  
Simulation Software ◽  
Hot Water ◽  
Government Support ◽  
Office Building ◽  
Radiation Balance ◽  
Solar Collectors

A solar collector market is most European countries is at the stage of continuous development, however its expansion rate differs. It shows that much more factors than only the local solar radiation is important, including a technology progress, costs, local manufactures’ engagement, an economic government support or an environmentally consciousness raising relevant to a mitigating climate change. We conducted the analysis for a public office building, with a few toilets and a social room, used by 54 people. As a primary heat source for HVAC and DHW systems an oil boiler was used, whereas solar collectors were considered as an energy source for hot water preparation. The analysis was conducted for three locations of the building: Bialystok (Poland), Cordoba (Spain) and Kaunas (Lithuania), using a simulation software delivered within the framework of VIPSKILLS project. Theoretical hot water consumption was considered as 3–7 dm3/(day person) in compliance with national recommendations. It was found that beam solar radiation share in a total radiation balance was nearly twice higher in Cordoba than in Bialystok or Kaunas. The highest efficiency (44%) was estimated in Cordoba for solar collectors installed with the tilt angle between 45–50°. In case of Bialystok and Kaunas the efficiency was lower than in Cordoba and nearly equal 40–41% and the recommended tilt angle was in a range 30– 45°.

Performance of the Flat Plate Solar Collector Operated with Water-Al2O3 Nanofluid

2016 ◽  
Vol 831 ◽  
pp. 181-187 ◽  
Author(s):  
Janusz T. Cieśliński ◽  
Bartosz Dawidowicz ◽  
Aleksandra Popakul
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Base Fluid ◽  
Fossil Fuels ◽  
Thermal Characteristics ◽  
Working Fluid ◽  
Solar Collectors ◽  
Recent Method ◽  
Flat Plate Solar Collector

Solar collectors is one of the technologies absorbing energy from solar beam and utilizing it for heating purposes, displacing the need to burn fossil fuels. There are many ways to improve effectiveness of the solar collectors [1,2]. Recent method to absorb more heat from the solar beam is to modify thermal characteristics of the working fluid. For this purpose one can use nanofluids, i.e. suspensions of metallic or nonmetallic nanoparticles in a base fluid [3].

scholarly journals Improving the Thermal Efficiency of Flat Plate Solar Collector Using Nano-Fluids as a Working Fluids: A Review

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Saif Ali Kadhim ◽  
Osama Abd AL-Munaf Ibrahim
Keyword(s):  
Flat Plate ◽  
Thermal Efficiency ◽  
Solar Collector ◽  
Base Fluid ◽  
Working Fluid ◽  
Solar Collectors ◽  
Nano Fluid ◽  
Flat Plate Solar Collector ◽  
Nano Fluids ◽  
Better Than

Solar energy is one of the most important types of renewable energy and is characterized by its availability, especially in Iraq. It can be used in many applications, including supply thermal energy by solar collectors. Improving the thermal efficiency of solar collector leads to an increase in the thermal energy supplied. Using a nano-fluid instead of base fluid (water is often used) as a working fluid is a method many used to increase the thermal efficiency of solar collectors. In this article, the latest research that used nano-fluid as a working fluid in evaluating the thermal efficiency of solar collector, type flat plate was reviewed. The thermal efficiency improvement of flat plate solar collector was reviewed based on the type of nanoparticles (metal oxides, semiconductors oxides, carbon compounds) used in the base fluid and comparison was made between these nanoparticles under the same conditions. Moreover, the effect of varying the concentration of nanoparticles in the base fluid and changing the working fluid flow rate on the thermal efficiency of flat plate solar collector was also reviewed. The results of the review showed that nano-fluids containing carbon compounds are better than other nano-fluids and that copper oxide is better than the rest of the metal oxides used in improving the thermal efficiency of flat plate solar collectors.

Preparation, stability and wettability of nanofluid: A review

2020 ◽  
Vol 14 (3) ◽  
pp. 7244-7257
Author(s):  
W. Safiei ◽  
M.M. Rahman ◽  
A.R. Yusoff ◽  
M.R. Radin
Keyword(s):  
Physical Properties ◽  
Working Fluid ◽  
Hybrid Nanofluid ◽  
Engineering Applications ◽  
Performance Preparation ◽  
Stable Suspension ◽  
The Stability ◽  
The Impact ◽  
Thermal Physical Properties

Nanofluids possess many advantages over conventional working fluid especially in physical, thermal and rheology properties. Nowadays, nanofluids have been applied extensively in many engineering applications in enhancing the overall performance. Preparation and characterization of nanofluids are vital as the nanomaterials have significant effects on the dispersion and stability of nanofluids. On the other hand, there is a trend to employ more than a single nanoparticle for preparing nanofluid. The hybrid nanofluid receives wide attention due to its capability in improving the thermal-physical properties of single phase nanofluids. In this paper, the flow of formulating nanofluid from preparation method, characterization, wettability analysis and stability techniques are discussed comprehensively. Furthermore, the challenges for obtaining stable suspension and wettability behaviour of nanofluids are discussed as well. The main objective when preparing the nanofluids is to obtain a well-dispersed nanoparticle into the base fluid. Based on the literature review, the impact of surfactant on the stability and the correlation between nanofluids wettability and thermal-physical properties of nanofluids have great potential to discover. There are some aspects that can be considered to expand the knowledge of nanofluids such as the composition ratio of hybrid nanofluid with regards to achieving the best stability and wettability study of hybrid nanofluid with and without surfactant in the suspension. Therefore, a lot of research should be conducted in order to explore the behaviour of nanofluid and the effect of various surfactants in terms of stability as well as its thermal and viscosity effect on the engineering applications.

scholarly journals A Theoretical Optimum Tilt Angle Model for Solar Collectors from Keplerian Orbit

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4454
Author(s):  
Tong Liu ◽  
Li Liu ◽  
Yufang He ◽  
Mengfei Sun ◽  
Jian Liu ◽  
...  
Keyword(s):  
Data Analysis ◽  
Solar Energy ◽  
Tilt Angle ◽  
Solar Collector ◽  
A Priori ◽  
Local Area ◽  
The Sun ◽  
Solar Collectors ◽  
Solar Altitude ◽  
Complete Set

Solar energy has been extensively used in industry and everyday life. A more suitable solar collector orientation can increase its utilization. Many studies have explored the best orientation of the solar collector installation from the perspective of data analysis and local-area cases. Investigating the optimal tilt angle of a collector from the perspective of data analysis, or guiding the angle of solar collector installation, requires an a priori theoretical tilt angle as a support. However, none of the current theoretical studies have taken the real motion of the Sun into account. Furthermore, a complete set of theoretical optimal tilt angles for solar energy is necessary for worldwide locations. Therefore, from the view of astronomical mechanics, considering the true orbit of the Sun, a mathematical model that is universal across the globe is proposed: the Kepler motion model is constructed from the solar orbit and transformed into the local Earth coordinate system. After that, the calculation of the optimal tilt angle solution is given. Finally, several examples are shown to demonstrate the variation of the optimal solar angle with month and latitude. The results show that for daily fixed solar collectors, the altitude angle of the collector should be about 6° above the noon solar altitude angle in summer and 6° lower in winter. For annual fixed collectors, the tilt angle should be slightly higher than the latitude. In summary, this study demonstrates that when a location is specified, this model can be used to calculate the theoretical optimum tilt angle of solar collectors for that position.

scholarly journals Experimental Analysis PVP Coated Silver Nanofluid Properties for Application in Photovoltaic/Thermal (PVT) Collectors

2020 ◽  
Vol 1 (3) ◽  
pp. 28-40
Author(s):  
A. Naderi ◽  
Gazori H. ◽  
M. Bozegi
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Base Fluid ◽  
Fossil Fuels ◽  
Working Fluid ◽  
Solar Collectors ◽  
Step Method ◽  
Energy Technologies ◽  
Pv Module ◽  
Utility Systems

Nowadays, supplying energy for the global population has turned into a prominent issue for countries engendering the consumption of huge amounts of fossil fuels which leads to some serious environmental problems. Among the renewable energy technologies, solar collectors can play major role to improve the efficiency, in air conditioning utility systems by minimum pollution. In photovoltaic/thermal (PVT) solar collectors, which are currently considered as the most advanced type to produce electricity and heat simultaneously, working fluid absorbs Energy from photovoltaic (PV) module engendering to decrease temperature of PV module and increase the electricity efficiency and also provide permissible amount of heat for other residential applications. Meanwhile, utilizing nanofluid as the working fluid in collector, regarding that the nanofluid has enhanced thermal properties relative to the base fluid, leads to a higher collector efficiency. In this research, PVP coated silver nanofluid was prepared in three volume concentration being 250, 500 and 1000 ppm by two-step method. To assess the stability of nanofluid the zeta potential is calculated which is obtained -41.6 V. Also, the prominent thermal properties of the nanofluid were analyzed regarding PVT solar collector applications. According to the results, thermal conductivity of the PVP coated silver nanofluid, improves the properties of base fluid, to the extent that thermal conductivity coefficient grows up 50% in some temperatures and increased from 0.594 for base fluid to 1.098 W/mK by escalation of concentration to 1000 ppm. Thus, PVP coated silver nanofluid can be deemed as the vital working fluid to improve the performance of PVT solar collectors.

scholarly journals OPTIMUM TILT ANGLE FOR MAXIMIZING LARGE SCALE SOLAR ELECTRICAL ENERGY OUTPUT

2021 ◽  
Vol 83 (3) ◽  
pp. 133-141
Author(s):  
Mohamed Nageh ◽  
Md Pauzi Abdullah ◽  
Belal Yousef
Keyword(s):  
Tilt Angle ◽  
Energy Production ◽  
Large Scale ◽  
Tracking System ◽  
Electrical Energy ◽  
Energy Output ◽  
Maintenance Cost ◽  
Construction Operation ◽  
Electrical Energy Production ◽  
The Impact

Many large-scale solar (LSS) plants that are being installed today have solar photovoltaic (PV) panels mounted on fixed structures, which limits its electrical energy production. Tracking system can be installed so that the PV panels could change its tilt angle automatically in accordance with the sun’s movement. However, it will increase the construction, operation and maintenance cost significantly. Another option is to manually adjust the tilt angle on periodically basis, but the time period and the optimum tilt angle need to be systematically determined. This paper investigates the impact of using monthly and seasonal optimum tilt angle, βopt on electrical energy production of LSS plant. The proposed strategy can be implemented by using tiltable solar panel mounting structures which is far cheaper than the tracking system. For the study, 1 MW LSS system model is used. Twelve cities around the globe with latitude angle ranging from 0º to 55º are strategically selected. The electrical energy output from the 1 MW LSS plant is simulated by using PV mathematical model that is developed in Matlab software. The overall results show that by adjusting the tilt angle of the PV modules into its optimum angle on monthly or seasonal basis, it would increase the generated energy output between 1.91% and 7.24% for monthly adjustments and between 1.59% and 6.06% for seasonal adjustments.

Experimental and numerical assessments of the effects of vacuum and solar film on the performance of low concentration eccentric solar collector

2021 ◽  
pp. 1-19
Author(s):  
Mavd P. R. Teles ◽  
K.A.R. Ismail
Keyword(s):  
Thermal Performance ◽  
Solar Collector ◽  
High Efficiency ◽  
Numerical Code ◽  
Working Fluid ◽  
Solar Collectors ◽  
Low Concentration ◽  
Lack Of Information ◽  
Collector Efficiency ◽  
Volume Method

Abstract Low concentration collectors are usually recommended for water heating and refrigeration systems. The literature reveals lack of information on numerical modeling, experimental data, and thermal performance of eccentric evacuated double tube solar collectors. This study is focused on eccentric solar collectors since this arrangement allows adequate concentration for achieving relatively high temperatures while having small size and occupying less space. The effects of the vacuum in the annular space and reflective film on the enhancement of working fluid heating and overall thermal performance were also assessed. An in-house numerical code using finite volume method was used to discretize the conservation equations and the predictions were validated by experimental results obtained from an experimental rig that was constructed and instrumented for outdoor tests. The experiments were performed in the city of Campinas-Brazil during the autumn season. The investigated versions of the eccentric double tube solar collector include a version with a reflective film and vacuum, a second version with a reflective film but without vacuum, a third arrangement without a reflective film but with vacuum and finally a version without both a reflective film and vacuum. The results showed that the version with reflective film and vacuum demonstrated high efficiency achieving 89%. The lowest efficiency of 42% was achieved by the version without both reflective film and vacuum. The comparative analysis of the four versions shows that the incorporation of reflective film increases the collector efficiency by 28%, while the vacuum increases the efficiency by about 1.3%.

Sign in / Sign up

Export Citation Format

Share Document