Accepted Manuscripts

Santhi Murthy Santhi Rekha and Sukruedee Sukchai
J. Sol. Energy Eng   doi: 10.1115/1.4039605
This paper mainly focuses on the design of solar concentric parabolic cooker with proper arrangement of Phase Change Material (PCM) heat storage system. The receiver is a hollow concentric cylinder with inner and outer radii are 0.09 m and 0.1 m respectively. The gap between the two layers of the receiver is 0.01 m and is filled with heat transfer oil. The receiver is surrounded by the vertical cylindrical PCM tubes of diameter 0.025 m. The modes of heat transfer radiation, convection and conduction are explained and analyzed by heat transfer network. The Schematic view of the receiver is shown by using SketchUp software. The performance parameters, heat loss factor, optical efficiency factor, cooking power of the solar cooker were calculated with and without PCM in the receiver. 7.74 and 2.46 are the heat loss factors and 0.098, 0.22 are the optical efficiency factors of the solar cooker without and with PCM presented in the receiver. The optical efficiency factor of the solar cooker with PCM receiver is 2 times more than that receiver without PCM. The cooking power of the solar cooker with PCM receiver is 125.3 W which is 65.6 W more than that of the cooking power without PCM receiver. From these results, it can be concluded that, design of PCM solar cooking system can expand the applicability of solar cookers as a compatible cooking solution for cooking applications instead of using fossil fuel based cooking systems.
TOPICS: Design, Solar energy, Phase change materials, Heat transfer, Heat losses, Convection, Heat storage, Radiation (Physics), Heat conduction, Computer software, Cylinders, Fossil fuels
Adeel Waqas and Ji Jie
J. Sol. Energy Eng   doi: 10.1115/1.4039550
Phase change materials are investigated in this study as an option to reduce the surface temperature of the PV cell during sunshine hours to enhance the electrical efficiency of the cells. For this purpose thermal energy balance model of the PV panel is integrated with PCM enthalpy model. The simulated results of the model have been validated with experimental results from the literature. The results indicate that PCM can be effectively used for limiting the temperature rise of the PV cell thus increasing the efficiency of the PV cell up to 10%. Peak temperature of the PV cell can be reduced from 86oC to 57oC during the hottest summer month. It has observed that maximum benefits can be obtained when PCM melting point is selected in such a way that there is 10oC to 12oC difference between melting point of PCM and average minimum ambient temperature of the hottest summer month. PCM selected in such way will also require minimum mass. In current study PCM with melting point of 40oC and 44oC provide the best result compared to the PCMs having melting point of 35oC and 30oC with average minimum ambient temperature of 28oC.
TOPICS: Cooling, Phase change materials, Climate, Temperature, Melting point, Sunlight, Electrical efficiency, Enthalpy, Thermal energy
Yosry A. Azzam and Nagwa Ibrahim
J. Sol. Energy Eng   doi: 10.1115/1.4039551
Few studies have been implemented to evaluate whether the renewable energy generation could fit into industrial locations in Saudi Arabia. We completed this feasibility study to investigate whether using photovoltaic (PV) solar arrays to power industrial cities at Saudi Arabia is economically feasible. The case study is a factory in Zulfi city, Riyadh Region. We used National Renewable Energy Laboratory's modeling tool, System Advisor Model (SAM) to evaluate the economic benefits of using a 150 kW DC PV system to cover 100% of the factory monthly power demand. Over 25 years, the system is estimated to generate about 6,000,000 kWh of electricity whose net savings are $398,000 (1 US$ is equal to about 3.75 Saudi Riyals) represented by a discounted cash flow. The proposed system will save the factory around $304,000 that would have to be paid in electric bills and will eliminate considerable amount of CO2 emissions. Sensitivity analysis has been conducted to determine the effects of underlying parameters on the economic feasibility of the proposed system. Levelized cost of electricity generated and net present value are used as indicators of proposed system feasibility. The results indicate that these projects can be profitable under some certain assumptions and can potentially be generalized for all industrial locations in Saudi Arabia.
TOPICS: Flow (Dynamics), Modeling, Solar energy, Carbon dioxide, Photovoltaic power systems, Renewable energy, Sensitivity analysis, Solar cell arrays, Emissions
Raed I. Bourisli, Mohammed A. Altarakma and Adnan A. Alanzi
J. Sol. Energy Eng   doi: 10.1115/1.4039447
A hybrid algorithm that combines genetic programming and genetic algorithms that deduces a closed-form correlation of building energy use is presented. Throughout the evolution, the terms, functions and form of the correlation are evolved via the genetic program. Whenever the fitness of the best correlation stagnates for a specific number of GP generations, the genetic algorithm optimizes the real-valued coefficients of each correlation in the population. When the GA, in turn, stagnates, correlations with optimized coefficients and powers are passed back to the GP for further search. The hybrid algorithm is applied to the problem of predicting energy use of a U-shape building. More than 800 buildings with various foot-print areas, relative compactness, window-to-wall ratio and projection factor values were simulated using the VisualDOE energy simulation engine. The algorithm tries to minimize the difference between simulated and predicted values by maximizing the R2 value. The algorithm was able to arrive at a closed-form correlation that combines the four building parameters, accurate to within 4%. The methodology can be easily used to model any type of data behavior in any engineering or non-engineering application.
TOPICS: Energy consumption, Genetic algorithms, Computer programming, Algorithms, Shapes, Structures, Engines, Simulation
Muzaffar Ali, Vladimir Vukovic, Hafiz Muhammad Ali and Nadeem Ahmed Sheikh
J. Sol. Energy Eng   doi: 10.1115/1.4039426
The demand for affordable, environmentally friendly and reliable air conditioning systems has led to the introduction of several standalone and/or hybrid alternatives. The technology of Desiccant Evaporative Cooling (DEC) has proven to be dependable and has gained success at places where initially it was deemed unfeasible. Today, a number of related technologies and configurations are available. Amongst them solar-assisted desiccant cooling system (SADCS) offers a cheap eco-friendly alternative especially in hybrid configurations. Most studies have investigated the performance of numerous SADCS configurations in specific climatic conditions; however, at the global scale no such study is available. The current study investigates five different SADCS configurations using Equation-based Object-Oriented (EOO) modelling and simulation approach in five different climatic conditions. The selected climatic conditions cover a wide range of global weather data including arid/semiarid (Karachi), dry summer tropical (Adelaide), mesothermal (Sao Paulo, Shanghai) to continental conditions (Vienna). The performance of all selected SADCS configurations (ventilation cycle, recirculation and ventilated-recirculation cycles, dunkle and ventilated-dunkle cycle) are analysed for specified cooling design day of the selected cities. A uniform system control strategy based on the idea of displacement distribution (ventilation) system is used for each configuration and climatic zone.
TOPICS: Cooling systems, Solar energy, Climate, Cycles, Ventilation, Design, Modeling, Displacement, Evaporative cooling, Simulation, Cooling, Air conditioning
Özgün Sener, Touraj Farsadi, Mehmet Ozan Gözcü and Altan Kayran
J. Sol. Energy Eng   doi: 10.1115/1.4039350
This article presents a comprehensive study of the evaluation of the effect of spar cap fiber orientation angle of composite blades with induced bending-torsion coupling (IBTC) on the aero-structural performance wind turbines. Aero-structural performance of wind turbines with IBTC blades is evaluated with the fatigue load mitigation in the whole wind turbine system, tower clearances, peak stresses in the blades and power generation of wind turbines. For this purpose, a full E-Glass/Epoxy reference blade has been designed, following the inverse design methodology for a five-megawatt wind turbine. An E-Glass/Epoxy blade with IBTC and novel, hybrid E-Glass/Carbon/Epoxy blades with IBTC have been designed and aeroelastic time-marching multibody simulations of the five-megawatt turbine systems, with the reference blade and the blades with IBTC, have been carried out using six different randomly generated turbulent wind profiles. Fatigue-equivalent loads (FEL) in the wind turbine have been determined as an average of the results obtained from the time response of six different simulations. The results reveal that certain hybrid blade designs with IBTC are more effective in fatigue load mitigation than the E-Glass-Epoxy blade with IBTC, and besides the fiber orientation angle, sectional properties of hybrid blades must be adjusted accordingly using proper number of Carbon/Epoxy layers in the sections of the blade with IBTC, in order to simultaneously reduce generator power losses and the FEL.
TOPICS: Fibers, Torsion, Blades, Wind turbines, Epoxy adhesives, Epoxy resins, Glass, Stress, Fatigue, Free electron lasers, Simulation, Engineering simulation, Carbon, Design methodology, Energy generation, Turbines, Turbulence, Composite materials, Wing spars, Generators, Spar platforms, Wind
Zakaria El Jaouhari, Youssef Zaz, Salah Moughyt, Omar El Kadmiri and Zakaria El Kadmiri
J. Sol. Energy Eng   doi: 10.1115/1.4039098
A design of solar tracker with a new tracking method based on computer vision techniques is presented in this paper. The proposed method extracts the sun coordinates (orientation ?, elevation f) in real time from hemispherical sky images using an image processing algorithm and then drives a pair of motors to move solar panels (or heliostat) toward the sun. To ensure a wide field of view, a camera equipped with a fisheye lens is used to acquire the whole sky images. The advantages of such a system are the high sensitivity to brightness comparing to the traditional photo sensors based trackers that making the system more efficient and able to determine the sun position even in cloudy days. It also operates independently of time and position which makes it reliable in case of mobile solar station, contrary to systems based on astronomical equations.
TOPICS: Design, Solar energy, Computers, Image processing, Sensors, Lenses (Optics), Motors, Brightness (Photometry), Algorithms

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