Search results for: forced convection solar dryer
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 2334

Search results for: forced convection solar dryer

2064 The Effect of Acid Treatment of PEDOT: PSS Anode for Organic Solar Cells

Authors: Ismail Borazan, Ayse Celik Bedeloglu, Ali Demir, David Carroll

Abstract:

In this project, PEDOT:PSS layer was treated with formic acid, sulphuric acid, and hydrochloric acid, methanol, acetone, and dichlorobenzene:methanol. The resistivity measurements with 2-probes were carried out and the best-chosen method was employed to make an organic solar cell device.

Keywords: organic solar cells, PEDOT:PSS, polymer electrodes, resistivity

Procedia PDF Downloads 780
2063 Design and Comparative Analysis of Grid-Connected Bipv System with Monocrystalline Silicon and Polycrystalline Silicon in Kandahar Climate

Authors: Ahmad Shah Irshad, Naqibullah Kargar, Wais Samadi

Abstract:

Building an integrated photovoltaic (BIPV) system is a new and modern technique for solar energy production in Kandahar. Due to its location, Kandahar has abundant sources of solar energy. People use both monocrystalline and polycrystalline silicon solar PV modules for the grid-connected solar PV system, and they don’t know which technology performs better for the BIPV system. This paper analyses the parameters described by IEC61724, “Photovoltaic System Performance Monitoring Guidelines for Measurement, Data Exchange and Analysis,” to evaluate which technology shows better performance for the BIPV system. The monocrystalline silicon BIPV system has a 3.1% higher array yield than the polycrystalline silicon BIPV system. The final yield is 0.2%, somewhat higher for monocrystalline silicon than polycrystalline silicon. Monocrystalline silicon has 0.2% and 4.5% greater yearly yield factor and capacity factors than polycrystalline silicon, respectively. Monocrystalline silicon shows 0.3% better performance than polycrystalline silicon. With 1.7% reduction and 0.4% addition in collection losses and useful energy produced, respectively, monocrystalline silicon solar PV system shows good performance than polycrystalline silicon solar PV system. But system losses are the same for both technologies. The monocrystalline silicon BIPV system injects 0.2% more energy into the grid than the polycrystalline silicon BIPV system.

Keywords: photovoltaic technologies, performance analysis, solar energy, solar irradiance, performance ratio

Procedia PDF Downloads 331
2062 The Development of Solar Cells to Maximize the Utilization of Solar Energy in Al-Baha Area

Authors: Mohammed Ahmed Alghamdi, Hazem Mahmoud Ali Darwish, Mostafa Mohamed Abdelraheem

Abstract:

Transparent conducting oxides (TCOs) possess low resistivity, exhibit good adherence to many substrates, and have good transmission characteristics from the visible to near-infrared wavelengths, which make it useful for various applications. Thin films of transparent conducting oxide (TCO’s) have received much attention because of their wide applications in the field of optoelectronic devices. Advancement of transparent conducting oxides TCO’s may not only lie within the improvement of existing materials in use, but also the development of novel materials. Solar cells are devices, which convert solar energy into electricity, either directly via the photovoltaic effect, or indirectly by first converting the solar energy to heat or chemical energy. Solar power has attracted attention of late as the most advanced of the alternative energy resources. The project aims to access the solar energy in Al-Baha region by search for materials (transparent-conductive oxides (TCO's)) to use in solar cells with highly transparent to the solar spectrum, have low electrical resistivity, be stable under H-plasma, and have a suitable structure in particular for a-Si solar cells. As the PV surface is exposed to the sunlight, the module temperature increases. High ambient temperatures along with long sunlight exposure time increases the temperature impact on PV cells efficiency. Since Al-Baha area is characterized by an atmosphere and pressure different from their counterparts in Saudi Arabia due to the height above sea level, hence it is appropriate to do studies to improve the efficiency of solar cells under these conditions. In this work, some ion change materials will be deposited using either sputtering/ or electron beam evaporation techniques. The optical properties of the synthesized materials will be studied in details for solar cell application. As we will study the effect of some dyes on the optical properties of the prepared films. The efficiency and other parameters of solar cell will be determined.

Keywords: thin films, solar cell, optical properties, electrical properties

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2061 Performance of a Solar Heating System on the Microclimate of an Agricultural Greenhouse

Authors: Nora Arbaoui, Rachid Tadili, Ilham Ihoume

Abstract:

Climate change and its effects on low external temperatures in winter require great consumption of energy to improve the greenhouse microclimate and increase agricultural production. To reduce the amount of energy consumed, a solar system has been developed to heat an agricultural greenhouse. This system is based on a transfer fluid that will circulate inside the greenhouse through a solar copper coil positioned on the roof of the greenhouse. This thermal energy accumulated during the day will be stored to be released during the night to improve the greenhouse’s microclimate. The use of this solar heating system has resulted in an average increase in the greenhouse’s indoor temperature of 8.3°C compared to the outdoor environment. This improved temperature has created a more favorable climate for crops and has subsequently had a positive effect on their development, quality, and production.

Keywords: solar system, agricultural greenhouse, heating, cooling, storage, drying

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2060 Solar Energy Technology Adoption; A Vignette Study for the Up-Scale Residential Sector in Egypt

Authors: Mazen Zaki, Sherwat E. Ibrahim

Abstract:

Renewable energy has become a very important and critical topic all around the world due to the limited resources that led to shifting to the trend of renewable energy and its integration with the conventional ones. This paper investigates the adoption of the solar energy technology for up-scale residential sector in Cairo, Egypt. The technology acceptance model uses several stakeholder points’ of views to develop vignettes to be used in examining the intention and attitude of the householders to adopt the solar energy technology.

Keywords: solar energy, technology acceptance model, TAM, stakeholder analysis, vignette, residential sector

Procedia PDF Downloads 116
2059 Solar Heating System to Promote the Disinfection

Authors: Elmo Thiago Lins Cöuras Ford, Valentina Alessandra Carvalho do Vale

Abstract:

It presents a heating system using low cost alternative solar collectors to promote the disinfection of water in low income communities that take water contaminated by bacteria. The system consists of two solar collectors, with total area of 4 m² and was built using PET bottles and cans of beer and soft drinks. Each collector is made up of 8 PVC tubes, connected in series and work in continuous flow. It will determine the flux the most appropriate to generate the temperature to promote the disinfection. Will be presented results of the efficiency and thermal loss of system and results of analysis of water after undergoing the process of heating.

Keywords: disinfection of water, solar heating system, poor communities, PVC

Procedia PDF Downloads 441
2058 Impact of Large Scale Solar Power Plant on Airports and Aviation

Authors: Munirah Stapah Salleh, Ahmad Rosly Abbas, Sazalina Zakaria, Nur Iffika Ruslan, Nurfaziera Rahim

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One of the areas that require a massive amount of energy is the airport. Hence, several airports have increased their reliance on renewable energy, specifically solar photovoltaic (PV) systems, to solve the issue. The interest regarding the installations of airport-based solar farms caught much attention. This, at the same time, helps to minimize the reliance on conventional energy sources that are fossil-based. However, many concerns were raised on the solar PV systems, especially on the effect of potential glare occurrence to the pilots during their flies. This paper will be discussing both the positive and negative impact of the large scale solar power plant on airports and aviation. Installing the large scale solar have negative impacts on airport and aviation, such as physical collision hazards, potential interference, or voltage problems with aircraft navigational and surveillance equipment as well as potential glare. On the positive side, it helps to lower environmental footprint, acquiring less energy from the utility provider, which are traditionally highly relying on other energy sources that have larger effects on the environment, and, last but not least, reduce the power supply uncertainty.

Keywords: solar photovoltaic systems, large scale solar, airport, glare effects

Procedia PDF Downloads 178
2057 Numerical Study of Rayleight Number and Eccentricity Effect on Free Convection Fluid Flow and Heat Transfer of Annulus

Authors: Ali Reza Tahavvor‚ Saeed Hosseini, Behnam Amiri

Abstract:

Concentric and eccentric annulus is used frequently in technical and industrial applications such as nuclear reactors, thermal storage system and etc. In this paper, computational fluid dynamics (CFD) is used to investigate two dimensional free convection of laminar flow in annulus with isotherm cylinders surface and cooler inner surface. Problem studied in thirty different cases. Due to natural convection continuity and momentum equations are coupled and must be solved simultaneously. Finite volume method is used for solving governing equations. The purpose was to obtain the eccentricity effect on Nusselt number in different Rayleight numbers, so streamlines and temperature fields must be determined. Results shown that the highest Nusselt number values occurs in degree of eccentricity equal to 0.5 upward for inner cylinder and degree of eccentricity equal to 0.3 upward for outer cylinder. Side eccentricity reduces the outer cylinder Nusselt number but increases inner cylinder Nusselt number. The trend in variation of Nusselt number with respect to eccentricity remain similar in different Rayleight numbers. Correlations are included to calculate the Nusselt number of the cylinders.

Keywords: natural convection, concentric, eccentric, Nusselt number, annulus

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2056 Solar and Wind Energy Potential Study of Lower Sindh, Pakistan for Power Generation

Authors: M. Akhlaque Ahmed, Sidra A. Shaikh, Maliha A. Siddiqui

Abstract:

Global and diffuse solar radiation on horizontal surface of Lower Sindh, namely Karachi, Hyderabad, Nawabshah were carried out using sunshine hour data of the area to assess the feasibility of solar energy utilization for power generation in Sindh province. The results obtained show a large variation in the direct and diffuse component of solar radiation in summer and winter months in Lower Sindh (50% direct and 50% diffuse for Karachi and Hyderabad). In Nawabshah area, the contribution of diffuse solar radiation is low during the monsoon months, July and August. The KT value of Nawabshah indicates a clear sky throughout almost the entire year. The percentage of diffuse radiation does not exceed more than 20%. In Nawabshah, the appearance of cloud is rare even during the monsoon months. The estimated values indicate that Nawabshah has high solar potential, whereas Karachi and Hyderabad have low solar potential. During the monsoon months the Lower part of Sindh can utilize the hybrid system with wind power. Near Karachi and Hyderabad, the wind speed ranges between 6.2 m/sec to 6.9 m/sec. A wind corridor exists near Karachi, Hyderabad, Gharo, Keti Bander and Shah Bander. The short fall of solar can be compensated by wind because in the monsoon months of July and August, wind speeds are higher in the Lower region of Sindh.

Keywords: hybrid power system, lower Sindh, power generation, solar and wind energy potential

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2055 Mapping of Solar Radiation Anomalies Based on Climate Change

Authors: Elison Eduardo Jardim Bierhals, Claudineia Brazil, Francisco Pereira, Elton Rossini

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The use of alternative energy sources to meet energy demand reduces environmental damage. To diversify an energy matrix and to minimize global warming, a solar energy is gaining space, being an important source of renewable energy, and its potential depends on the climatic conditions of the region. Brazil presents a great solar potential for a generation of electric energy, so the knowledge of solar radiation and its characteristics are fundamental for the study of energy use. Due to the above reasons, this article aims to verify the climatic variability corresponding to the variations in solar radiation anomalies, in the face of climate change scenarios. The data used in this research are part of the Intercomparison of Interconnected Models, Phase 5 (CMIP5), which contributed to the preparation of the fifth IPCC-AR5 report. The solar radiation data were extracted from The Australian Community Climate and Earth System Simulator (ACCESS) model using the RCP 4.5 and RCP 8.5 scenarios that represent an intermediate structure and a pessimistic framework, the latter being the most worrisome in all cases. In order to allow the use of solar radiation as a source of energy in a given location and/or region, it is important, first, to determine its availability, thus justifying the importance of the study. The results pointed out, for the 75-year period (2026-2100), based on a pessimistic scenario, indicate a drop in solar radiation of the approximately 12% in the eastern region of Rio Grande do Sul. Factors that influence the pessimistic prospects of this scenario should be better observed by the responsible authorities, since they can affect the possibility to produce electricity from solar radiation.

Keywords: climate change, energy, IPCC, solar radiation

Procedia PDF Downloads 157
2054 Simulation and Experimentation of Solar Thermal Collector for Air Heating System Using Dynamic Ribs

Authors: Nishitha Chowdary, Prabhav Dwivedi

Abstract:

Solar radiation (or insolation) is responsible for 174 petawatts (PW) of energy reaching the Earth's atmosphere. About one-third of this is reflected in space. Solar energy is by far the most abundant source of energy on Earth. In this study to use solar energy to the fullest in a solar air heater, An analysis of a solar air heater duct roughened with fixed cylindrical ribs in 3-D has been done using CFD. These fixed cylindrical ribs have a uniform circular cross-section and are placed in transverse in-line and staggered arrangements. The orientation of ribs has been fixed and is perpendicular to the in-flow direction. Cylindrical ribs are arranged periodically with fixed pitch; therefore, one pitch length is only considered in the present study. Validation has been done with smooth as well as with roughened duct and is matched perfectly with the developed correlations. Geometric parameters, namely rib height (e), ranges from 1 to 2 mm and pitch ranges from 10 to 40 mm are used in the present investigation. Thermo-hydraulic performance parameters in terms of average Nusselt number and friction factor have been extracted for Reynolds number ranging 5000—18000 to optimize the performance of roughened duct.

Keywords: cylindrical ribs, solar air heater, thermo-hydraulic performance factor, roughened duct

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2053 Numerical Study of Natural Convection in a Triangular Enclosure as an Attic for Different Geometries and Boundary Conditions

Authors: H. Golchoobian, S. Saedodin, M. H. Taheri, A. Sarafraz

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In this paper, natural convection in an attic is numerically investigated. The geometry of the problem is considered to be a triangular enclosure. ANSYS Fluent software is used for modeling and numerical solution. This study is for steady state. Four right-angled triangles with height to base ratios of 2, 1, 0.5 and 0.25 are considered. The behavior of various parameters related to its performance, including temperature distribution and velocity vectors are evaluated, and graphs for the Nusselt number have been drawn. Also, in this study, the effect of geometric shape of enclosure with different height-to-base ratios has been evaluated for three types of boundary conditions of winter, summer day and one another state. It can be concluded that as the bottom side temperature and ratio of base to height of the enclosure increases, the convective effects become more prominent and circulation happened.

Keywords: enclosure, natural convection, numerical solution, Nusselt number, triangular

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2052 Modeling of a Concentrating Photovoltaic Module with and without Cooling System

Authors: Intissar Benrhouma, Marta Victoria, Ignacio Anton, Bechir Chaouachi

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Concentrating photovoltaic systems CPV use optical elements, such as Fresnel lenses, to concentrate solar intensity. The concentrated solar energy is delivered to the solar cell from 20 to 100 W/cm². Some of this energy is converted to electricity, while the rest must be disposed of as a residual heat. Solar cells cooling should be a necessary part of CPV modeling because these systems allowed increasing the power received by the cell. This high power can rise the electrons’ potential causing the heating of the cell, which reduces the global module’s efficiency. This work consists of modeling a concentrating photovoltaic module with and without a cooling system. We have established a theoretical model based on energy balances carried out on a photovoltaic module using solar radiation concentration cells. Subsequently, we developed a calculation program on Matlab which allowed us to simulate the functioning of this module. The obtained results show that the addition of a cooling system to the module improves greatly the performance of our CPV system.

Keywords: solar energy, photovoltaic, concentration, cooling, performance improvement

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2051 Vehicle to Grid Potential for Solar Powered Electric Vehicle

Authors: Marcin Kowalski, Tomasz Wiktor, Piotr Ladonski, Krzysztof Bortnowski, Szymon Przybyl, Mateusz Grzesiak

Abstract:

This paper provides a detailed overview of the so-called smart grid or vehicle-to-grid idea, including a description of our way of implementation. The primary targets of this paper are technical students, young constructors, visionaries, however more experienced designers may find useful ideas for developing their vehicles. The publication will also be useful for home-grown builders who want to save on electricity. This article as well summarizes the advantages and disadvantages of V2G solution and might be helpful for students teams planning to participate in Bridgestone World Solar Challenge.

Keywords: solar powered vehicle, vehicle to grid, electric car, v2g, bridgestone world solar challenge

Procedia PDF Downloads 172
2050 Forced Vibration of a Planar Curved Beam on Pasternak Foundation

Authors: Akif Kutlu, Merve Ermis, Nihal Eratlı, Mehmet H. Omurtag

Abstract:

The objective of this study is to investigate the forced vibration analysis of a planar curved beam lying on elastic foundation by using the mixed finite element method. The finite element formulation is based on the Timoshenko beam theory. In order to solve the problems in frequency domain, the element matrices of two nodded curvilinear elements are transformed into Laplace space. The results are transformed back to the time domain by the well-known numerical Modified Durbin’s transformation algorithm. First, the presented finite element formulation is verified through the forced vibration analysis of a planar curved Timoshenko beam resting on Winkler foundation and the finite element results are compared with the results available in the literature. Then, the forced vibration analysis of a planar curved beam resting on Winkler-Pasternak foundation is conducted.

Keywords: curved beam, dynamic analysis, elastic foundation, finite element method

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2049 Numerical Study of Natural Convection Heat Transfer in a Two-Dimensional Vertical Conical PartiallyAnnular Space

Authors: Belkacem Ould Said, Nourddine Retiel, Abdelilah Benazza, Mohamed Aichouni

Abstract:

In this paper, a numerical study of two-dimensional steady flow has been made of natural convection in a differentially heated vertical conical partially annular space. The heat transfer is assumed to take place by natural convection. The inner and outer surfaces of annulus are maintained at uniform wall temperature. The annulus is filled with air. The CFD FLUENT12.0 code is used to solve the governing equations of mass, momentum and energy using constant properties and the Boussinesq approximation for density variation. The streamlines and the isotherms of the fluid are presented for different annuli with different boundary conditions and Rayleigh numbers. Emphasis is placed on the influences of the height of the inner vertical cone on the flow and the temperature fields. In addition, the effects on the heat transfer are discussed for various values of physical parameters of the fluid and geometric parameters of the annulus. The heat transfer on the hot walls of the annulus is also calculated in order to make comparisons between the cylinder annulus for boundary conditions and several Rayleigh numbers. A good agreement of Nusselt number has been found between the present predictions and reference from the literature data.

Keywords: natural convection, heat transfer, numerical simulation, conical partially, annular space

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2048 Forced Degradation Study of Rifaximin Formulated Tablets to Determine Stability Indicating Nature of High-Performance Liquid Chromatography Analytical Method

Authors: Abid Fida Masih

Abstract:

Forced degradation study of Rifaximin was conducted to determine the stability indicating potential of HPLC testing method for detection of Rifaximin in formulated tablets to be employed for quality control and stability testing. The questioned method applied with mobile phase methanol: water (70:30), 5µm, 250 x 4.6mm, C18 column, wavelength 293nm and flow rate of 1.0 ml/min. Forced degradation study was performed under oxidative, acidic, basic, thermal and photolytic conditions. The applied method successfully determined the degradation products after acidic and basic degradation without interfering with Rifaximin detection. Therefore, the method was said to be stability indicating and can be applied for quality control and stability testing of Rifaxmin tablets during its shelf life.

Keywords: forced degradation, high-performance liquid chromatography, method validation, rifaximin, stability indicating method

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2047 Practical Evaluation of High-Efficiency Si-based Tandem Solar Cells

Authors: Sue-Yi Chen, Wei-Chun Hsu, Jon-Yiew Gan

Abstract:

Si-based double-junction tandem solar cells have become a popular research topic because of the advantages of low manufacturing cost and high energy conversion efficiency. However, there is no set of calculations to select the appropriate top cell materials. Therefore, this paper will propose a simple but practical selection method. First of all, we calculate the S-Q limit and explain the reasons for developing tandem solar cells. Secondly, we calculate the theoretical energy conversion efficiency of the double-junction tandem solar cells while combining the commercial monocrystalline Si and materials' practical efficiency to consider the actual situation. Finally, we conservatively conclude that if considering 75% performance of the theoretical energy conversion efficiency of the top cell, the suitable bandgap energy range will fall between 1.38eV to 2.5eV. Besides, we also briefly describe some improvements of several proper materials, CZTS, CdSe, Cu2O, ZnTe, and CdS, hoping that future research can select and manufacture high-efficiency Si-based tandem solar cells based on this paper successfully. Most importantly, our calculation method is not limited to silicon solely. If other materials’ performances match or surpass silicon's ability in the future, researchers can also apply this set of deduction processes.

Keywords: high-efficiency solar cells, material selection, Si-based double-junction solar cells, Tandem solar cells, photovoltaics.

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2046 Integration of Hydropower and Solar Photovoltaic Generation into Distribution System: Case of South Sudan

Authors: Ater Amogpai

Abstract:

Hydropower and solar photovoltaic (PV) generation are crucial in sustainability and transitioning from fossil fuel to clean energy. Integrating renewable energy sources such as hydropower and solar photovoltaic (PV) into the distributed networks contributes to achieving energy balance, pollution mitigation, and cost reduction. Frequent power outages and a lack of load reliability characterize the current South Sudan electricity distribution system. The country’s electricity demand is 300MW; however, the installed capacity is around 212.4M. Insufficient funds to build new electricity facilities and expand generation are the reasons for the gap in installed capacity. The South Sudan Ministry of Energy and Dams gave a contract to an Egyptian Elsewedy Electric Company that completed the construction of a solar PV plant in 2023. The plant has a 35 MWh battery storage and 20 MW solar PV system capacity. The construction of Juba Solar PV Park started in 2022 to increase the current installed capacity in Juba City to 53 MW. The plant will begin serving 59000 residents in Juba and save 10,886.2t of carbon dioxide (CO2) annually.

Keywords: renewable energy, hydropower, solar energy, photovoltaic, South Sudan

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2045 Space Weather and Earthquakes: A Case Study of Solar Flare X9.3 Class on September 6, 2017

Authors: Viktor Novikov, Yuri Ruzhin

Abstract:

The studies completed to-date on a relation of the Earth's seismicity and solar processes provide the fuzzy and contradictory results. For verification of an idea that solar flares can trigger earthquakes, we have analyzed a case of a powerful surge of solar flash activity early in September 2017 during approaching the minimum of 24th solar cycle was accompanied by significant disturbances of space weather. On September 6, 2017, a group of sunspots AR2673 generated a large solar flare of X9.3 class, the strongest flare over the past twelve years. Its explosion produced a coronal mass ejection partially directed towards the Earth. We carried out a statistical analysis of the catalogs of earthquakes USGS and EMSC for determination of the effect of solar flares on global seismic activity. New evidence of earthquake triggering due to the Sun-Earth interaction has been demonstrated by simple comparison of behavior of Earth's seismicity before and after the strong solar flare. The global number of earthquakes with magnitude of 2.5 to 5.5 within 11 days after the solar flare has increased by 30 to 100%. A possibility of electric/electromagnetic triggering of earthquake due to space weather disturbances is supported by results of field and laboratory studies, where the earthquakes (both natural and laboratory) were initiated by injection of electrical current into the Earth crust. For the specific case of artificial electric earthquake triggering the current density at a depth of earthquake, sources are comparable with estimations of a density of telluric currents induced by variation of space weather conditions due to solar flares. Acknowledgment: The work was supported by RFBR grant No. 18-05-00255.

Keywords: solar flare, earthquake activity, earthquake triggering, solar-terrestrial relations

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2044 Electric Power Generation by Thermoelectric Cells and Parabolic Solar Concentrators

Authors: A. Kianifar, M. Afzali, I. Pishbin

Abstract:

In this paper, design details, theoretical analysis and thermal performance analysis of a solar energy concentrator suited to combined heat and thermoelectric power generation are presented. The thermoelectric device is attached to the absorber plate to convert concentrated solar energy directly into electric energy at the focus of the concentrator. A cooling channel (water cooled heat sink) is fitted to the cold side of the thermoelectric device to remove the waste heat and maintain a high temperature gradient across the device to improve conversion efficiency.

Keywords: concentrator thermoelectric generator, CTEG, solar energy, thermoelectric cells

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2043 Effects of G-jitter Combined with Heat and Mass Transfer by Mixed Convection MHD Flow of Maxwell Fluid in a Porous Space

Authors: Faisal Salah, Z. A. Aziz, K. K. Viswanathan

Abstract:

In this article, the effects of g-jitter induced and combined with heat and mass transfer by mixed convection of MHD Maxwell fluid in microgravity situation is investigated for a simple system. This system consists of two heated vertical parallel infinite flat plates held at constant but different temperatures and concentrations. By using modified Darcy’s law, the equations governing the flow are modelled. These equations are solved analytically for the induced velocity, temperature and concentration distributions. Many interesting available results in the relevant literature (i.e. Newtonian fluid) is obtained as the special case of the present general analysis. Finally, the graphical results for the velocity profile of the oscillating flow in the channel are presented and discussed for different values of the material constants.

Keywords: g-jitter, heat and mass transfer, mixed convection, Maxwell fluid, porous medium

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2042 Magneto-Hydrodynamic Mixed Convection of Water-Al2O3 Nanofluid in a Wavy Lid-Driven Cavity

Authors: Farshid Fathinia

Abstract:

This paper examines numerically the laminar steady magneto-hydrodynamic mixed convection flow and heat transfer in a wavy lid-driven cavity filled with water-Al2O3 nanofluid using FDM method. The left and right sidewalls of the cavity have a wavy geometry and are maintained at a cold and hot temperature, respectively. The top and bottom walls are considered flat and insulated while, the bottom wall moves from left to right direction with a uniform lid-driven velocity. A magnetic field is applied vertically downward on the bottom wall of the cavity. Based on the numerical results, the effects of the dominant parameters such as Rayleigh number, Hartmann number, solid volume fraction, and wavy wall geometry parameters are examined. The numerical results are obtained for Hartmann number varying as 0 ≤ Ha ≤ 0.6, Rayleigh numbers varying as 103≤ Ra ≤105, and the solid volume fractions varying as 0 ≤ φ ≤ 0.0003. Comparisons with previously published numerical works on mixed convection in a nanofluid filled cavity are performed and good agreements between the results are observed. It is found that the flow circulation and mean Nusselt number decrease as the solid volume fraction and Hartmann number increase. Moreover, the convection enhances when the amplitude ratio of the wavy surface increases. The results also show that both the flow and thermal fields are significantly affected by the amplitude ratio (i.e., wave form) of the wavy wall.

Keywords: nanofluid, mixed convection, magnetic field, wavy cavity, lid-driven, SPH method

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2041 Solar and Wind Energy Potential Study of Sindh Province, Pakistan for Power Generation

Authors: M. Akhlaque Ahmed, Sidra A. Shaikh, Maliha A. Siddiqui, Adeel Tahir

Abstract:

Global and diffuse solar radiation on horizontal surface of southern sindh namely Karachi, Hyderabad, Nawabshah were carried out using sunshine hour data of the area to asses the feasibility of solar Energy utilization at Sindh province for power generation. From the observation, result is derived which shows a drastic variation in the diffuse and direct component of solar radiation for summer and winter for Southern Sindh that is both contributes 50% for Karachi and Hyderabad. In Nawabshah area, the contribution of diffuse solar radiation is low in monsoon months, July and August. The Kᴛ value of Nawabshah indicates a clear sky almost throughout the year. The percentage of diffuse radiation does not exceed more than 20%. In Nawabshah, the appearance of cloud is rare even in monsoon months. The estimated values indicate that Nawabshah has high solar potential whereas Karachi and Hyderabad has low solar potential. During the monsoon months, the southern part of Sind can utilize the hybrid system with wind power. Near Karachi and Hyderabad, the wind speed ranges between 6.2 to 6.9 m/sec. There exist a wind corridor near Karachi, Hyderabad, Gharo, Keti Bander and Shah Bander. The short fall of solar can be compensated by wind because in monsoon months July and August the wind speed are higher in the southern region of Sindh.

Keywords: hybrid power system, power generation, solar and wind energy potential, southern Sindh

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2040 Research on the Effect of Accelerated Aging Illumination Mode on Bifacial Solar Modules

Authors: T. H. Huang, C. L. Fern, Y. K. Tseng

Abstract:

The design and reliability of solar photovoltaic modules are crucial to the development of solar energy, and efforts are still being made to extend the life of photovoltaic modules to improve their efficiency because natural aging is time-consuming and does not provide manufacturers and investors with timely information, accelerated aging is currently the best way to estimate the life of photovoltaic modules. Bifacial solar cells not only absorb light from the front side but also absorb light reflected from the ground on the back side, surpassing the performance of single-sided solar cells. Due to the asymmetry of the two sides of the light, in addition to the difference in photovoltaic conversion efficiency, there will also be differences in heat distribution, which will affect the electrical properties and material structure of the bifacial solar cell itself. In this study, there are two types of experimental samples: packaged and unpackaged and then irradiated with UVC light sources and halogen lamps for accelerated aging, as well as a control group without aging. After two weeks of accelerated aging, the bifacial solar cells were visual observation, and infrared thermal images were taken; then, the samples were subjected to IV measurement, and samples were taken for SEM, Raman, and XRD analyses in order to identify the defects that lead to failure and chemical changes, as well as to analyze the reasons for the degradation of their characteristics. From the results of the analysis, it is found that aging will cause carbonization of the polymer material on the surface of bifacial solar cells, and the crystal structure will be affected.

Keywords: bifacial solar cell, accelerated aging, temperature, characterization, electrical measurement

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2039 Impact of Forced Displacement on Place Attachment and Home Perception of Internally Displaced Turkish Cypriots

Authors: Makbule Oktay

Abstract:

Home is a significant entity in people’s lives. It is a place that provides shelter to people and a place to which one feels a sense of attachment and belonging. It is an entity that people develop feelings and meaning to it. People – place bond, or in other words place attachment, and home perception might alter as a consequence of lifetime experiences. Thus, forced displacement appears as a dramatic experience for people who lose their homes, belongings and communities. It impacts people who involuntarily leave their homes and belongings behind, experience physical, social, cultural and economic disruption and are forced to settle in an unfamiliar environment. Place attachment and home perception of internally displaced people who involuntarily leave their homes might be different from those who haven’t experience forced displacement. Although place attachment, meaning of home and forced displacement are the subjects that have been broadly studied, there is a lack of studies which question the relation between the three subjects in general and on Turkish Cypriot case in particular. Considering this, it is the aim of this paper to investigate the impact of forced displacement to internally displaced people’s attachment to a particular place and home perception. To do so, the study focuses on internally displaced Turkish Cypriots who have been internally displaced as a result of conflict. Interview and questionnaire as two of the commonly used techniques in the place attachment and home perception studies have been used in this study too. The results of the study indicate that internal displacement has an apparent impact on place attachment of forcibly displaced people. As a consequence of longstanding displacement, forcibly displaced people developed multiple attachments. Compared to people who have not experienced displacement, forcibly displaced people have low attachments. Forced displacement does not strongly impact the home perception in terms of meaning of home in longstanding displacement situations even though displacement-related meanings of home exist.

Keywords: forcibly displaced people, home perception, internal displacement, place attachment, Turkish Cypriots

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2038 Investigation of Solar Concentrator Prototypes under Tunisian Conditions

Authors: Moncef Balghouthi, Mahmoud Ben Amara, Abdessalem Ben Hadj Ali, Amenallah Guizani

Abstract:

Concentrated solar power technology constitutes an interesting option to meet a part of future energy demand, especially when considering the high levels of solar radiation and clearness index that are available particularly in Tunisia. In this work, we present three experimental prototypes of solar concentrators installed in the research center of energy CRTEn in Tunisia. Two are medium temperature parabolic trough solar collector used to drive a cooling installation and for steam generation. The third is a parabolic dish concentrator used for hybrid generation of thermal and electric power. Optical and thermal evaluations were presented. Solutions and possibilities to construct locally the mirrors of the concentrator were discussed. In addition, the enhancement of the performances of the receivers by nano selective absorption coatings was studied. The improvement of heat transfer between the receiver and the heat transfer fluid was discussed for each application.

Keywords: solar concentrators, optical and thermal evaluations, cooling and process heat, hybrid thermal and electric generation

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2037 Modeling and Simulation of Organic Solar Cells Based on P3HT:PCBM using SCAPS 1-D (Influence of Defects and Temperature on the Performance of the Solar Cell)

Authors: Souhila Boukli Hacene, Djamila Kherbouche, Abdelhak Chikhaoui

Abstract:

In this work, we elucidate theoretically the effect of defects and temperature on the performance of the organic bulk heterojunction solar cell (BHJ) P3HT: PCBM. We have studied the influence of their parameters on cell characteristics. For this purpose, we used the effective medium model and the solar cell simulator (SCAPS) to model the characteristics of the solar cell. We also explore the transport of charge carriers in the device. It was assumed that the mixture is lightly p-type doped and that the band gap contains acceptor defects near the HOMO level with a Gaussian distribution of energy states at 100 and 50 meV. We varied defects density between 1012-1017 cm-3, from 1016 cm-3, a total decrease of the photovoltaic characteristics due to the increase of the non-radiative recombination can be noticed. Then we studied the effect of variation of the electron and the hole capture cross-section on the cell’s performance, we noticed that the cell obtains a better efficiency of about 3.6% for an electron capture cross section ≤ 10-15 cm2 and a hole capture cross section ≤ 10-19 cm2. On the other hand, we also varied the temperature between 120K and 400K. We observed that the temperature of the solar cell induces a noticeable effect on its voltage. While the effect of temperature on the solar cell current is negligible.

Keywords: organic solar cell, P3HT:PCBM, defects, temperature, SCAPS

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2036 Solar Heating System to Promote the Disinfection of Water

Authors: Elmo Thiago Lins Cöuras Ford, Valentina Alessandra Carvalho do Vale

Abstract:

It presents a heating system using low cost alternative solar collectors to promote the disinfection of water in low income communities that take water contaminated by bacteria. The system consists of two solar collectors, with total area of 4 m² and was built using PET bottles and cans of beer and soft drinks. Each collector is made up of 8 PVC tubes, connected in series and work in continuous flow. It will determine the flux the most appropriate to generate the temperature to promote the disinfection. It will be presented results of the efficiency and thermal loss of system and results of analysis of water after undergoing the process of heating.

Keywords: Disinfection of water, solar heating system, poor communities, bioinformatics, biomedicine

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2035 Two-Dimensional Analysis and Numerical Simulation of the Navier-Stokes Equations for Principles of Turbulence around Isothermal Bodies Immersed in Incompressible Newtonian Fluids

Authors: Romulo D. C. Santos, Silvio M. A. Gama, Ramiro G. R. Camacho

Abstract:

In this present paper, the thermos-fluid dynamics considering the mixed convection (natural and forced convections) and the principles of turbulence flow around complex geometries have been studied. In these applications, it was necessary to analyze the influence between the flow field and the heated immersed body with constant temperature on its surface. This paper presents a study about the Newtonian incompressible two-dimensional fluid around isothermal geometry using the immersed boundary method (IBM) with the virtual physical model (VPM). The numerical code proposed for all simulations satisfy the calculation of temperature considering Dirichlet boundary conditions. Important dimensionless numbers such as Strouhal number is calculated using the Fast Fourier Transform (FFT), Nusselt number, drag and lift coefficients, velocity and pressure. Streamlines and isothermal lines are presented for each simulation showing the flow dynamics and patterns. The Navier-Stokes and energy equations for mixed convection were discretized using the finite difference method for space and a second order Adams-Bashforth and Runge-Kuta 4th order methods for time considering the fractional step method to couple the calculation of pressure, velocity, and temperature. This work used for simulation of turbulence, the Smagorinsky, and Spalart-Allmaras models. The first model is based on the local equilibrium hypothesis for small scales and hypothesis of Boussinesq, such that the energy is injected into spectrum of the turbulence, being equal to the energy dissipated by the convective effects. The Spalart-Allmaras model, use only one transport equation for turbulent viscosity. The results were compared with numerical data, validating the effect of heat-transfer together with turbulence models. The IBM/VPM is a powerful tool to simulate flow around complex geometries. The results showed a good numerical convergence in relation the references adopted.

Keywords: immersed boundary method, mixed convection, turbulence methods, virtual physical model

Procedia PDF Downloads 91