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Accepted Manuscripts

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Technical Brief  
Leanne Reich, Luke Melmoth, Lindsey Yue, Roman Bader, Robert Gresham, Terrence Simon and Wojciech Lipinski
J. Sol. Energy Eng   doi: 10.1115/1.4037089
An engineering design for a 1-kW solar-driven reactor to capture carbon dioxide via the calcium oxide based two-step carbonation-calcination cycle has been completed. The reactor consists of a downward-facing cylindrical dual cavity. The inner cavity serves as the radiation receiver, while the outer cavity is the reaction chamber that contains a packed- or fluidized-bed of CaO particles. Several aspects have been incorporated in this reactor design, including high flexibility, mechanical rigidity and simplicity, high-temperature and thermal shock resistance, accommodation of thermal expansion, low convective heat losses, uniform gas distribution inside the reaction chamber, and simple reactor assembly. The final reactor design is presented and the reactor assembly is illustrated.
TOPICS: Design, Solar energy, Carbon dioxide, Cavities, Manufacturing, Engineering design, Thermal expansion, Radiation (Physics), Particulate matter, Cycles, Fluidized beds, Heat losses, Stiffness, Thermal shock, High temperature
research-article  
James Allan, Zahir Dehouche, Sinisa Stankovic and Alan Harries
J. Sol. Energy Eng   doi: 10.1115/1.4037090
Numerical simulation enables the optimization of a solar collector without the expense of building prototypes. This study details an approach using Computational Fluid Dynamics (CFD) to simulate the performance of a solar thermal collector. Inputs to the simulation include; heat loss coefficient, irradiance and ambient temperature. A simulated thermal efficiency was validated using experimental results by comparing the calculated heat removal factor. The validated methodology was then applied to five different inlet configurations of a header-riser collector. The most efficient designs had uniform flow through the risers. The worst performing configurations had low flow rates in the risers that led to high surface temperatures and poor thermal efficiency. The calculated heat removal factor differed by between 4.2% for the serpentine model and 12.1% for the header riser. The discrepancies were attributed to differences in thermal contact between plate and tubes in the simulated and actual design.
TOPICS: Simulation, Computational fluid dynamics, Design, Solar collectors, Pipeline risers, Risers (Casting), Thermal efficiency, Flow (Dynamics), Heat, Temperature, Computer simulation, Optimization, Engineering prototypes, Heat losses
research-article  
Qinwei Ding, Chun Li, Binxin Li, Wenxing Hao and Zhou Ye
J. Sol. Energy Eng   doi: 10.1115/1.4037091
The stability of platform structure is the paramount guarantee of the safe operation of the offshore floating wind turbine. The NREL 5MW floating wind turbine is established based on the OC3-Hywind Spar Buoy platform with the supplement of helical strakes for the purpose to analysis the impact of helical strakes on the dynamic response of the floating wind turbine Spar platform. The dynamic response of floating wind turbine Spar platform under wind, wave and current loading from the impact of number, height and pitch ratio of the helical strakes is analysed by the radiation and diffraction theory, the finite element method and orthogonal design method. The result reveals that the helical strakes can effectively inhibit the dynamic response of the platform but enlarge the wave exciting force; the best parameter combination is 2 pieces of helical strakes with height of 15%D and the pitch ratio of 5; the height of the helical strake and its pitch ratio have significant influence on pitch response.
TOPICS: Optimization, Dynamic response, Design, Floating wind turbines, Spar platforms, Wind waves, Buoys, Stability, Diffraction, Radiation (Physics), Waves, Finite element methods, Design methodology
research-article  
Hamidreza Khakrah, Amir Shamloo and Siamak Kazemzadeh Hannani
J. Sol. Energy Eng   doi: 10.1115/1.4037092
Due to significant reduce in fossil fuel sources; several researches have been conducted recently to explore modern sources of renewable energy. One of the major fields in the category of renewable energy harnessing devices is parabolic trough solar collectors (PTC). Several parameters have effect on the overall efficiency of the PTC’s. As the effect of these parameters is coupled to each other, a comprehensive investigation is necessary. In the present study a numerical analysis is performed to examine the efficiency of PTCs via variation of several involving parameters (et. wind velocity magnitude, nanoparticles volume fraction, inlet temperature and reflector’s orientation). A detailed set of absorber, reflector, and protection glass in addition to the surrounding environment is modeled to capture sufficiently accurate data. The working fluid is assumed to be nanofluid to inspect the advantageous of metallic nanoparticle addition to the base fluid. The Monte Carlo radiation tracing method is utilized to calculate the solar gain on the absorber tube.
TOPICS: Solar collectors, Nanofluids, Renewable energy, Nanoparticles, Fluids, Glass, Radiation (Physics), Wind velocity, Numerical analysis, Solar energy, Fossil fuels, Parabolic troughs, Temperature
research-article  
Desh Bandhu Singh and GN Tiwari
J. Sol. Energy Eng   doi: 10.1115/1.4036855
In this paper, analytical expression for characteristic equation of double slope solar still included with series connected N identical evacuated tubular collectors (N-ETC-DS) has been developed. The derivation is based on fundamental energy balance equations for various components of the proposed system. The analytical result of the proposed N-ETC-DS has been compared with results reported by earlier researchers for the same basin area under similar climatic condition. It has been concluded that daily energy efficiency is higher by 23.90%, 26.45% and 42.65% for N-ETC-DS than N identical partially covered photovoltaic thermal (PVT) compound parabolic concentrator collectors integrated double slope solar still, N identical partially covered PVT flat plate collectors integrated double slope solar still and conventional double slope solar still respectively at 0.14 m water depth under optimized condition. Moreover, daily yield, exergy, energy and exergy efficiency have been computed.
TOPICS: Solar stills, Exergy, Flat plates, Water, Energy efficiency, Energy budget (Physics)

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