scholarly journals Design a New Receiver for the Central Tower of Solar Energy

2018 ◽  
Vol 225 ◽  
pp. 02009
Author(s):  
Ayad K. Khlief ◽  
Syed I.U. Gilani ◽  
Hussain H. Al-Kayiem ◽  
Sanan T. Mohammad
Keyword(s):  
Thermal Efficiency ◽  
Energy Input ◽  
Radiative Heat ◽  
Heat Losses ◽  
Solar Irradiation ◽  
Solar Systems ◽  
Proposed Model ◽  
Simulation Results ◽  
Solar Receiver ◽  
Evacuated Tube

Heat loss is an important factor in the performance of the solar receiver for concentrated solar systems (CSP). This study presents a proposed model for a new design for the receiver using an evacuated tube that has been performed to reduce convection loss and radiative heat losses with a zigzag distribution to minimize spillage losses. In this study, simulation results showed that the energy input increases with increased solar irradiation; the increase ranges from 3429 to 5584 W and 1879 to 3875 W at 9 AM and 13 PM for preheater and superheater respectively. The thermal efficiency of the receiver was around 72%.

Three-Dimensional Fluid Dynamics and Radiative Heat Transfer Modeling of a Small Particle Solar Receiver

2013 ◽  
Author(s):  
Pablo Fernández del Campo ◽  
Fletcher Miller ◽  
Adam Crocker
Keyword(s):  
Heat Transfer ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Small Particle ◽  
Radiative Heat ◽  
Three Dimensional ◽  
Solar Irradiation ◽  
Ansys Fluent ◽  
Solar Receiver

We present an investigation of the effects of the solar irradiation and mass flow conditions on the behavior of a Small Particle Solar Receiver employing our new, three-dimensional coupled fluid flow and radiative heat transfer model. This research expands on previous work conducted by our group and utilizes improved software with a set of new features that allows performing more flexible simulations and obtaining more accurate results. For the first time, it is possible not only to accurately predict the overall efficiency and the wall temperature distribution of the solar receiver, but also to determine the effect on the receiver of the window, the outlet tube, real solar irradiation from a heliostat field, non-cylindrical geometries and 3-D effects. This way, a much better understanding of the receiver’s capabilities is obtained. While the previous models were useful to observe simple trends, this new software is flexible and accurate enough to eventually act as a design and optimization tool for the actual receiver. The solution procedure relies on the coupling of the CFD package ANSYS Fluent to our in-house Monte Carlo Ray Trace (MCRT) software. On the one hand, ANSYS Fluent is utilized as the mass-, momentum- and energy-equation solver and requires the divergence of the radiative heat flux, which constitutes a source term of the energy equation. On the other hand, the MCRT software calculates the radiation heat transfer in the solar receiver and needs the temperature field to do so. By virtue of the coupled nature of the problem, both codes should provide feed-back to each other and iterate until convergence. The coupling between ANSYS Fluent and our in-house MCRT code is done via User-Defined Functions. After developing the mathematical model, setting up and validating the software, and optimizing the coupled solution procedure, the receiver has been simulated under fifteen different solar irradiation and mass flow rate cross combinations. Among other results, the behavior of the receiver at different times of the day and the optimum mass flow rate as a function of the solar thermal input are presented. On an average day, the thermal efficiency of the receiver is found to be over 89% and the outlet temperature over 1250 K at all times from 7:30 AM to 4:00 PM (Albuquerque, NM) by properly adapting the mass flow rate. The origin of the losses and how to improve the efficiency of the Small Particle Solar Receiver are discussed as well.

scholarly journals Thermal Efficiency of a New Prototype of Evacuated Tube Collector using Sn-Al2O3 as a Selective Solar Absorber

2018 ◽  
Vol 15 (11) ◽  
pp. 793-802
Author(s):  
Warisa WAMAE ◽  
Tawat SURIWONG ◽  
Thotsaphon THRERUJIRAPAPONG
Keyword(s):  
Thermal Efficiency ◽  
Al2o3 Layer ◽  
Solar Absorptance ◽  
Solar Absorber ◽  
Solar Absorbers ◽  
Evacuated Tube Collector ◽  
Distribution Of Elements ◽  
Solar Receiver ◽  
Tin Content ◽  
Evacuated Tube

Three tin pigmented aluminium oxide (Sn-Al2O3)films were prepared with different tin content using an anodization process, which is applied as a selective solar absorber in a new prototype of evacuated tube collector (ETC). The morphology and distribution of elements on the coatings were characterized using a Scanning Electron Microscope (SEM) equipped with an Energy Dispersive X-ray (EDX) analyzer. The spectrally selective properties, defined as the ratio of solar absorptance (αsol) to thermal emittance (εtherm) were examined. In order to investigate the thermal performance of ETC using Sn-Al2O3 on an Al fin as a solar receiver, thermal efficiency (η) of the ETC was collected under steady-state conditions, as prescribed by ISO 9806-1 standard. The results, of the Sn-Al2O3 coatings reached a darker black colour with an increase in the colouring time. The samples were composed of different contents of Sn in the Al2O3 layer. The solar selectivity (αsol/εtherm) significantly increased with the increases in Sn content. The maximum thermal efficiency (ηmax) of the ETC under the nearly constant heat loss coefficient (UL), was obviously increased with the increasing Sn content. Therefore, the Sn-Al2O3 with different Sn contents is a good candidate for selective solar absorbers in a new prototype of ETC.

scholarly journals Experimental Investigation on Evaluation of Thermal Performance of Solar Heating System Using Al2O3 Nanofluid

2020 ◽  
Vol 10 (16) ◽  
pp. 5521 ◽  
Author(s):  
Youngho Lee ◽  
Hyomin Jeong ◽  
Ji-Tae Park ◽  
Antonio Delgado ◽  
Sedong Kim
Keyword(s):  
Power Systems ◽  
Electronic Conductivity ◽  
Heating System ◽  
Solar Irradiation ◽  
Working Fluid ◽  
Solar Systems ◽  
Collector System ◽  
Thermal Changes ◽  
Transfer Properties ◽  
Al2o3 Nanofluid

Over the years, solar collecting systems have gained interest in renewable energy. This study investigated improving the efficiency of the working fluid in thermal solar systems by using nanofluids with three concentrations of alumina, 0.1, 0.3, and 0.5 wt%. The UV-vis absorbance, electronic conductivity, and thermal transfer properties of the nanofluids were analyzed, and the thermal changes with exposure to solar radiation in an experimental collector system were measured by pyranometer. The electronic conductivity, thermal conductivity, and UV-vis absorbance increased with the alumina concentration. Moreover, the temperatures of the nanofluids increased more under solar irradiation than that of distilled water. This implies that the alumina nanofluids absorb solar energy more efficiently than water. The findings of this study suggest that the use of both alumina nanofluids and nanoparticles will improve the efficiency of thermal solar power systems.

Wear of a Tool in Double-Disk Lapping of Silicon Wafers

2010 ◽  
Author(s):  
Adam Barylski ◽  
Mariusz Deja
Keyword(s):  
Experimental Data ◽  
Integrated Circuits ◽  
Tool Wear ◽  
Silicon Wafers ◽  
Silicon Ingot ◽  
Proposed Model ◽  
Tool Wear Prediction ◽  
Simulation Results ◽  
High Degree ◽  
Kinematical Parameters

Silicon wafers are the most widely used substrates for fabricating integrated circuits. A sequence of processes is needed to turn a silicon ingot into silicon wafers. One of the processes is flattening by lapping or by grinding to achieve a high degree of flatness and parallelism of the wafer [1, 2, 3]. Lapping can effectively remove or reduce the waviness induced by preceding operations [2, 4]. The main aim of this paper is to compare the simulation results with lapping experimental data obtained from the Polish producer of silicon wafers, the company Cemat Silicon from Warsaw (www.cematsil.com). Proposed model is going to be implemented by this company for the tool wear prediction. Proposed model can be applied for lapping or grinding with single or double-disc lapping kinematics [5, 6, 7]. Geometrical and kinematical relations with the simulations are presented in the work. Generated results for given workpiece diameter and for different kinematical parameters are studied using models programmed in the Matlab environment.

Effect of Carbon Particle Feeding as Radiant Absorbent for Enhanced Heat Transfer

2021 ◽  
pp. 1-15
Author(s):  
Hamed Abedini ◽  
Nesrin Ozalp
Keyword(s):  
Heat Transfer ◽  
Particle Size ◽  
Temperature Profile ◽  
Energy Absorption ◽  
Carbon Particle ◽  
Carbon Particles ◽  
Solar Reactor ◽  
Simulation Results ◽  
Particle Feeding ◽  
Solar Receiver

Abstract Carbon particles can be used as catalyst in solar reactors where they serve as radiant absorbent and nucleation sites for the heterogeneous decomposition reaction. Unlike commonly used metal catalysts, carbon catalyst does not have durability problem and high cost. However, in order to achieve sustainable catalytic decomposition of feedstock over carbon catalysts at elevated temperatures, the surface area of the carbon particles must be maintained. A subsequent treatment of deactivated carbon samples with CO2 at about 1000 °C would increase the surface and would recover the original activity as catalyst. In a windowed solar reactor, carbon particles are directly exposed to the high flux irradiation providing efficient radiation heat transfer directly to the reaction site. Therefore, one of the key parameters to achieve higher conversion efficiencies in a solar reactor is the presence and transport of carbon particles. In this paper, a transient one-dimensional model is presented to describe effect of carbon particle feeding on energy transport and temperature profile of a cavity-type solar receiver. The model was developed by dividing the receiver into several control volumes and formulating energy balance equations for gas phase, particles, and cavity walls within each control volume. Monte Carlo ray tracing (MCRT) method was used to determine the solar heat absorbed by particles and cavity walls, as well as the radiative exchange between particles and cavity walls. Model accuracy was verified by experimental work using a solar receiver where carbon particles were injected uniformly. Comparison of simulation results with the experimentally measured temperatures at three different locations on cavity receiver wall showed an average deviation of 3.81%. The model was then used to study the effect of carbon particle size and feeding rate on the heat transfer, temperature profile, and energy absorption of the solar receiver. Based on the simulation results, it was found that injection of carbon particles with a size bigger than 500 µm has no significant influence on heat transfer of the system. However, by reducing the particle size lower than 500 µm, temperature uniformity and energy absorption were enhanced.

Methods of Mathematical Modeling of the Leaching Process of Cobalt-Containing Solutions

2021 ◽  
Vol 316 ◽  
pp. 661-666
Author(s):  
Nataliya V. Mokrova
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Chemical Kinetics ◽  
Group Method ◽  
Data Handling ◽  
Multistage Processes ◽  
Leaching Process ◽  
Proposed Model ◽  
Simulation Results ◽  
The Mathematical Model

Current cobalt processing practices are described. This article discusses the advantages of the group argument accounting method for mathematical modeling of the leaching process of cobalt solutions. Identification of the mathematical model of the cascade of reactors of cobalt-producing is presented. Group method of data handling is allowing: to eliminate the need to calculate quantities of chemical kinetics; to get the opportunity to take into account the results of mixed experiments; to exclude the influence of random interference on the simulation results. The proposed model confirms the capabilities of the group method of data handling for describing multistage processes.

scholarly journals Estimation of Solar Irradiation on Inclined Surface Based on Web Databases

2014 ◽  
Vol 60 (4) ◽  
pp. 315-320 ◽  
Author(s):  
Gustaw Mazurek
Keyword(s):  
Solar Irradiation ◽  
Pv System ◽  
Solar Systems ◽  
Pv Systems ◽  
Pv Modules ◽  
Tilted Plane ◽  
Annual Scale ◽  
Inclined Surface ◽  
Long Operation ◽  
Good Agreement

Abstract Estimation of Global Tilted Irradiation (GTI) is a key to performance assessment of typical solar systems since they usually employ tilted photovoltaic (PV) modules or collectors. Numerous solar radiation databases can deliver irradiation values both on horizontal and tilted plane, however they are validated mostly with horizontal-plane ground measurements. In this paper we have compared GTI estimates retrieved from five Internet databases with results of measurements at two PV systems located in Poland. Our work shows that in spite of good agreement in annual scale, there is a tendency to underestimate GTI in summer and overestimate in winter, when PV modules can receive less than a half of expected irradiation. The latter issue affects sizing of PV system components and implies a correction needed to achieve all-year long operation.

ACCURATE ANALYSIS OF GLOBAL INTERCONNECTS IN NANO-FPGAs

NANO ◽  
2009 ◽  
Vol 04 (03) ◽  
pp. 171-176 ◽  
Author(s):  
DAVOOD FATHI ◽  
BEHJAT FOROUZANDEH
Keyword(s):  
Propagation Delay ◽  
Modeling Method ◽  
Accurate Analysis ◽  
Proposed Model ◽  
Simulation Results ◽  
The Difference ◽  
A New Technique ◽  
Global Interconnects ◽  
Technology Nodes ◽  
Model Technique

This paper introduces a new technique for analyzing the behavior of global interconnects in FPGAs, for nanoscale technologies. Using this new enhanced modeling method, new enhanced accurate expressions for calculating the propagation delay of global interconnects in nano-FPGAs have been derived. In order to verify the proposed model, we have performed the delay simulations in 45 nm, 65 nm, 90 nm, and 130 nm technology nodes, with our modeling method and the conventional Pi-model technique. Then, the results obtained from these two methods have been compared with HSPICE simulation results. The obtained results show a better match in the propagation delay computations for global interconnects between our proposed model and HSPICE simulations, with respect to the conventional techniques such as Pi-model. According to the obtained results, the difference between our model and HSPICE simulations in the mentioned technology nodes is (0.29–22.92)%, whereas this difference is (11.13–38.29)% for another model.

scholarly journals Performance study of MATLAB modelled PV panel and conventional PV panel interfaced with LabVIEW

2018 ◽  
Vol 7 (2.17) ◽  
pp. 70
Author(s):  
Jaiganesh K ◽  
Karuppiah N ◽  
Ravivarman S ◽  
Md Asif
Keyword(s):  
Electrical Energy ◽  
Black Body ◽  
Atmospheric Temperature ◽  
Climatic Conditions ◽  
Solar Irradiation ◽  
Irradiation Condition ◽  
Solar Pv ◽  
Performance Study ◽  
Pv Panel ◽  
Proposed Model

The maximum electrical energy conversion efficiency of the Solar PV panel is up to 22% in normal conventional roof- top system under the temperature of 25˚C on Standard Test Condition (STC). In Indian climatic conditions, the atmospheric temperature is mostly above 35˚C to 45˚C, it incites 35˚C to 80˚C temperature on the PV panel. The black body of the PV panel absorbs more heat. This temperature affects the electrical efficiency of the panel significantly. This paper proposes the mathematical modelling of the solar PV panel for different solar irradiation and the temperature. The experimental evaluation is conducted in the latitude of 11.36 (N) and longitude 77.82 (E). The testing and monitoring was done with LabVIEW based National Instruments hardware such as NI cDAQ-9178, NI DAQ - 9227 and NI DAQ 9225. The comparative study between the simulated result and real time hardware results are discussed in this paper. The test result shows that the output of the proposed model mismatches with the experimental output of the solar PV panel due to the negative correlation between the efficiency and temperature for variable irradiation condition. It shows a power difference of 9.41W between the output of the proposed model and the experimental setup.  

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