scholarly journals Experimental investigation of solar compound parabolic collector using Al2O3/H2O nanofluid in a subtropical climate

2020 ◽  
pp. 201-201
Author(s):  
Faria Akhtar ◽  
Muzaffar Ali ◽  
Nadeem Sheikh ◽  
Muhammad Shehryar
Keyword(s):  
Base Fluid ◽  
Concentration Ratio ◽  
Heat Transfer Fluid ◽  
Subtropical Climate ◽  
Solar Concentrator ◽  
Acceptance Angle ◽  
Flow Rates ◽  
Climate Conditions ◽  
Medium Range ◽  
Parabolic Collector

Different solar concentrator technologies are used for low-medium range temperature applications. In this paper, a non-tracking compound parabolic collector with a nanofluid is experimentally analyzed under real climate conditions of a typical sub-tropical climate Taxila, Pakistan. The collector used for the experimentation has concentration ratio of 4.17, collector area of 0.828 m2 and half acceptance angle of 24?. The heat transfer fluid used for the study is water based nanofluid with particles of Al2O3. The investigation is carried out at three different volumetric concentrations (0.025%, 0.05%,0.075%) of nanofluids at flowrates of 0.01 kg/s, 0.02 kg/s, 0.05 kg/s and 0.07 kg/s are compared with base fluid (water). Comparison of system thermal efficiency, solar heat gain, and temperature difference is presented for different selected days in real climate conditions during months of March to May. It is observed that performance of the compound parabolic collector is improved by 8%, 11%, 14% and 19%, respectively at considered flow rates compared to water.

A New Troughlike Nonimaging Solar Concentrator

2001 ◽  
Vol 124 (1) ◽  
pp. 51-54 ◽  
Author(s):  
Eduardo A. Rinco´n ◽  
Fidel A. Osorio
Keyword(s):  
Concentration Ratio ◽  
Glass Tube ◽  
Two Dimensional ◽  
Solar Concentrator ◽  
Steam Generation ◽  
Acceptance Angle ◽  
Practical Applications ◽  
Optimal Shapes ◽  
Heating Steam ◽  
East West

A new two-dimensional concentrator for solar energy collection has been developed. The concentrator has the following advantages, when compared with the classic Compound Parabolic Concentrators invented by Roland Winston, W. T. Welford, A. Rabl, Baranov, and other researchers: 1) It allows the use of parabolic mirrors, which have a reflecting area much smaller for a given concentration ratio and acceptance angle. 2) Between the mirror and the absorber, there is a large gap so that conduction losses are reduced. Convection losses can be reduced, too, if the absorber is enclosed within a glass tube. 3) It can be easily manufactured. Instead of seeking the shape of the mirrors for a given shape of the absorber, we have made the inverse statement of the problem, and we have obtained the optimal shapes of the absorbers with a prescribed acceptance angle, for parabolic mirrors, assuming that the intercept factor is unity, the mirrors are perfect, and the absorber surfaces are convex. The concentrator should be east-west oriented, and could be seasonal or monthly tilt adjusted. This concentrator could have many practical applications, such as fluid heating, steam generation, etc.

scholarly journals Monte Carlo Ray-Tracing Simulation of a Cassegrain Solar Concentrator Module for CPV

2021 ◽  
Vol 9 ◽  
Author(s):  
Seung Jin Oh ◽  
Hyungchan Kim ◽  
Youngsun Hong
Keyword(s):  
Monte Carlo ◽  
Ray Tracing ◽  
Concentration Ratio ◽  
Collection Efficiency ◽  
Focal Length ◽  
Tracking Error ◽  
Target Area ◽  
Solar Concentrator ◽  
Acceptance Angle ◽  
Energy Applications

The concentration ratio is one of the most important characteristics in designing a Cassegrain solar concentrator since it directly affects the performance of high-density solar energy applications such as concentrated photovoltaics (CPVs). In this study, solar concentrator modules that have different configurations were proposed and their performances were compared by means of a Monte Carlo ray-tracing algorithm to identify the optimal configurations. The first solar concentrator design includes a primary parabolic concentrator, a parabolic secondary reflector, and a homogenizer. The second design, on the other hand, includes a parabolic primary concentrator, a secondary hyperbolic concentrator, and a homogenizer. Two different reflectance were applied to find the ideal concentration ratio and the actual concentration ratio. In addition, uniform rays and solar rays also were compared to estimate their efficiency. Results revealed that both modules show identical concentration ratios of 610 when the tracking error is not considered. However, the concentration ratio of the first design rapidly drops when the sun tracking error overshoots even 0.1°, whereas the concentration ratio of the second design remained constant within the range of the 0.8° tracking error. It was concluded that a paraboloidal reflector is not appropriate for the second mirror in a Cassegrain concentrator due to its low acceptance angle. The maximum collection efficiency was achieved when the f-number is smaller and the rim angle is bigger and when the secondary reflector is in a hyperboloid shape. The target area has to be rather bigger with a shorter focal length for the secondary reflector to obtain a wider acceptance angle.

Experimental Study on Thermal Efficiency of Parabolic Trough Collector (PTC) Using Al2O3/H2O Nanofluid

2015 ◽  
Vol 787 ◽  
pp. 192-196
Author(s):  
E. Siva Reddy ◽  
R. Meenakshi Reddy ◽  
K. Krishna Reddy
Keyword(s):  
Experimental Study ◽  
Solar Energy ◽  
Thermal Efficiency ◽  
Base Fluid ◽  
Concentration Ratio ◽  
Volume Fraction ◽  
Nano Particles ◽  
Parabolic Trough ◽  
Flow Rates ◽  
Parabolic Trough Collector

Dispersing small amounts of solid nano particles into base-fluid has a significant impact on the thermo-physical properties of the base-fluid. These properties are utilized for effective capture and transportation of solar energy. This paper attempts key idea for harvesting solar energy by using alumina nanofluid in concentrating parabolic trough collectors. An experimental study is carried out to investigate the performance of a parabolic trough collector using Al2O3-H2O based nanofluid. Results clearly indicate that at same ambient, inlet temperatures, flow rate, concentration ratio etc. hike in thermal efficiency is around 5-10 % compared to the conventional Parabolic Trough Collector (PTC). Further, the effect of various parameters such as concentration ratio, receiver length, fluid velocity, volume fraction of nano particles has been studied. The different flow rates employed in the experiment are 2 ml/s, 4 ml/s and 6 ml/s. Volumetric concentration of 0.02%, 0.04% and 0.06% has been studied in the experiment. Surfactants are not introduced to avoid bubble formation. Tracking mode of parabolic trough collector is manual. Results also reveal that Al2O3-H2O based nanofluid has higher efficiency at higher flow rates.

An Outdoor Experiment of a Lens-Walled Compound Parabolic Concentrator Photovoltaic Module on a Sunny Day in Nottingham

2013 ◽  
Vol 136 (2) ◽  
Author(s):  
Guiqiang Li ◽  
Yuehong Su ◽  
Gang Pei ◽  
Hang Zhou ◽  
Xu Yu ◽  
...  
Keyword(s):  
Concentration Ratio ◽  
Good Choice ◽  
Experimental Results ◽  
Photovoltaic Module ◽  
Solar Concentrator ◽  
Acceptance Angle ◽  
Compound Parabolic Concentrator ◽  
Pv Module ◽  
Outdoor Experiment ◽  
East West

A lens-walled compound parabolic concentrator (lens-walled CPC) has a larger half acceptance angle than a mirror CPC for the same geometrical concentration ratio of 2.5X, so it would be more suitable for the building-integrated application as a stationary solar concentrator. Based on our previous work, an outdoor experimental study of a sample trough lens-walled CPC PV module under sunny condition in Nottingham is described. The experimental results provide the verification of actual larger half acceptance angle obtained by the lens-walled CPC in comparison with a mirror CPC of the same size. Along with the analysis of the projected incidence angles, the experimental results also indicate that the lens-walled CPC of 2.5X orientated east–west may be a good choice for high latitude area as a stationary solar concentrator to give a satisfactory whole year performance.

scholarly journals Design and Evaluation of Polygonal Trough Solar Concentrator

2021 ◽  
Vol 34 (4) ◽  
pp. 10-16
Author(s):  
Yasser Yassin Khudair ◽  
Alaa Badr Hasan
Keyword(s):  
Concentration Ratio ◽  
Angle Of Incidence ◽  
Solar Concentrator ◽  
Acceptance Angle ◽  
Optical Efficiency ◽  
Cylindrical Mirror ◽  
Design For All ◽  
Reflecting Surfaces ◽  
Reflecting Surface ◽  
To Receive

     In this paper, a solar concentrator is designed in the form of a concave half-cylindrical mirror consisting of polygonal reflective surface plates. The plates are arranged to give a hemispherical shape to the design. These surfaces work to receive solar radiation and focusing by reflecting it to the receiver that is placed in front of the reflecting surfaces. The results are compared with a system consisting of a concave reflecting surface of the same dimensions to obtain a good criterion for evaluating the design performance. The results showed a low acceptance angle for the design for all the samples used due to the geometrical design nature. The optical efficiency affected by the angle of incidence greatly by all the samples used, which differ in the concentration ratio, width and location of the receiver.

scholarly journals Design and Fabrication of Absorptive/Reflective Crossed CPC PV/T System

Designs ◽  
2018 ◽  
Vol 2 (3) ◽  
pp. 29
Author(s):  
Muhsin Aykapadathu ◽  
Mehdi Nazarinia ◽  
Nazmi Sellami
Keyword(s):  
Numerical Control ◽  
Solar Concentrator ◽  
Cnc Milling ◽  
Acceptance Angle ◽  
Optical Efficiency ◽  
Compound Parabolic Concentrator ◽  
Building Integrated Photovoltaic ◽  
New Generation ◽  
Experimental Rig ◽  
T System

A crossed compound parabolic concentrator (CCPC) is a non-imaging concentrator which is a modified form of a circular 3D compound parabolic concentrator (CPC) obtained by orthogonal intersection of two 2D CPCs that have an optical efficiency in line with that of 3D CPC. The present work is about the design and fabrication of a new generation of solar concentrator: the hybrid photovoltaic (PV)/thermal absorptive/reflective CCPC module. The module has a 4× CCPC structure truncated to have a concentration of 3.6× with a half acceptance angle of 30°. Furthermore, an experimental rig was also fabricated to test the performance of the module and its feasibility in real applications such as building-integrated photovoltaic (BIPV). 3D printing and Computer Numerical Control (CNC) milling technologies were utilized to manufacture the absorber and reflective parts of the module.

scholarly journals Calorimetric Evaluation of Novel Concentrating Solar Receiver Geometries With Enhanced Effective Solar Absorptance

2016 ◽  
Author(s):  
Jesus D. Ortega ◽  
Julius E. Yellowhair ◽  
Clifford K. Ho ◽  
Joshua M. Christian ◽  
Charles E. Andraka
Keyword(s):  
Thermal Efficiency ◽  
Solar Power ◽  
Solar Furnace ◽  
Heat Transfer Fluid ◽  
Discrete Ordinates ◽  
Base Case ◽  
Outlet Temperature ◽  
Black Paint ◽  
Solar Absorptance ◽  
Flow Rates

Direct solar power receivers consist of tubular arrays, or panels, which are typically tubes arranged side by side and connected to an inlet and outlet manifold. The tubes absorb the heat incident on the surface and transfer it to the fluid contained inside them. To increase the solar absorptance, high temperature black paint or a solar selective coating is applied to the surface of the tubes. However, current solar selective coatings degrade over the lifetime of the receiver and must be reapplied, which reduces the receiver thermal efficiency and increases the maintenance costs. This work presents an evaluation of several novel receiver shapes which have been denominated as fractal like geometries (FLGs). The FLGs are geometries that create a light-trapping effect, thus, increasing the effective solar absorptance and potentially increasing the thermal efficiency of the receiver. Five FLG prototypes were fabricated out of Inconel 718 and tested in Sandia’s solar furnace at two irradiance levels of ∼15 and 30 W/cm2 and two fluid flow rates. Photographic methods were used to capture the irradiance distribution on the receiver surfaces and compared to results from ray-tracing models. This methods provided the irradiance distribution and the thermal input on the FLGs. Air at nearly atmospheric pressure was used as heat transfer fluid. The air inlet and outlet temperatures were recorded, using a data acquisition system, until steady state was achieved. Computational fluid dynamics (CFD) models, using the Discrete Ordinates (DO) radiation and the k-ω Shear Stress Transport (SST) equations, were developed and calibrated, using the test data, to predict the performance of the five FLGs at different air flow rates and irradiance levels. The results showed that relative to a flat plate (base case), the new FLGs exhibited an increase in the effective solar absorptance from 0.86 to 0.92 for an intrinsic material absorptance of 0.86. Peak surface temperatures of ∼1000°C and maximum air temperature increases of ∼200°C were observed. Compared to the base case, the new FLGs showed a clear air outlet temperature increase. Thermal efficiency increases of ∼15%, with respect to the base case, were observed. Several tests, in different days, were performed to assess the repeatability of the results. The results obtained, so far, are very encouraging and display a very strong potential for incorporation in future solar power receivers.

scholarly journals Phenology, production and quality of blueberry produced in humid subtropical climate

2018 ◽  
Vol 40 (3) ◽  
Author(s):  
José Gilberto Sousa Medeiros ◽  
Luiz Antonio Biasi ◽  
Claudine Maria de Bona ◽  
Francine Lorena Cuquel
Keyword(s):  
Fruit Set ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Subtropical Climate ◽  
Blue Color ◽  
Productive Performance ◽  
Climate Conditions ◽  
Mass Size ◽  
Fruit Mass

Abstract Studies on adaptation to the cultivation site are necessary for the recommendation of new cultivars. The aim of this study was to evaluate the phenological development, productivity and fruit quality of eight blueberry cultivars from the rabbiteye group (Aliceblue, Bluebelle, Bluegem, Briteblue, Climax, Delite, Powderblue and Woodard) and two from the highbush group (Georgiagem and O’Neal) under humid subtropical conditions in the 2012/2013, 2013/2014 and 2014/2015 cycles. Beginning and end of flowering, beginning and end of harvesting, fruit set, production, mass, diameter, pH, content of soluble solids, titratable acidity, ratio and coloring were evaluated. The evaluated cultivars presented flowering in the period from July to September, concentrating harvest in the months of November and December. The highest fruit set was observed in Delite, Climax, Briteblue and Powderblue cultivars. There were differences among cultivars regarding fruit mass, size, pH, content of soluble solids and acidity. The results showed that the cultivars exhibited blue color with few variations over the evaluation years. Cultivars with the best productive performance under humid subtropical climate conditions are Bluegem, Delite, Climax and Powderblue.

scholarly journals Numerical Climatic Analysis of Soybean Development in Sowing Dates in Humid Subtropical Climate

2021 ◽  
Author(s):  
Mateus Possebon Bortoluzzi ◽  
Arno Bernardo Heldwein ◽  
Roberto Trentin ◽  
Ivan Carlos Maldaner ◽  
Jocélia Rosa da Silva ◽  
...  
Keyword(s):  
Meteorological Data ◽  
Sowing Date ◽  
Cycle Duration ◽  
Subtropical Climate ◽  
Climate Conditions ◽  
Development Cycle ◽  
Sowing Dates ◽  
Climatological Station ◽  
The Mean ◽  
Santa Maria

Abstract The objective of this study was to determine the mean duration and the interannual variability of phenological subperiods and total soybean development cycle for 11 sowing dates in the humid subtropical climate conditions of the state of Rio Grande do Sul. Daily meteorological data were used from 1971 to 2017 obtained from the Pelotas agroclimatological station and from 1968 to 2017 from the main climatological station of Santa Maria. The soybean development simulation was performed considering three sets of cultivars of relative maturity groups between 5.9-6.8, 6.9-7.3 and 7.4-8.0, with intervals between the sowing dates of approximately 10 days, comprising September, 21 to December, 31. The data of phenological subperiods duration and total development cycle were subjected to the exploratory analysis BoxPlot, analysis of variance and mean comparison by the Scott-Knott test, with 5% of probability. The development cycle duration is greater in Pelotas than in Santa Maria. There was a decrease in soybean cycle duration from the first to the last sowing date for both locations. The R1-R5 subperiod duration is decreasing from October to December due to photoperiod reduction.

Characteristics of the InGaP/InGaAs/Ge Triple-Junction Solar Cells with Concentration Photovoltaic System

2011 ◽  
Vol 148-149 ◽  
pp. 773-777
Author(s):  
Zi Long Wang ◽  
Hua Zhang ◽  
Hai Tao Zhang ◽  
Ye Li
Keyword(s):  
Solar Cell ◽  
Concentration Ratio ◽  
Photovoltaic System ◽  
Solar Concentrator ◽  
Solar Pv ◽  
System Research ◽  
Uniform Illumination ◽  
Automatic Tracking ◽  
Second Stage ◽  
System A

The research on automatic tracking solar concentrator photovoltaic system research has become one of issues of solar PV technology. Aiming at the problem of cell performance degradation which caused by the non-uniform illumination in the concentrating photovoltaic system. A dish-style concentrating photovoltaic system with second stage concentrator was designed and built in this article. The author measured the performance of three junction GaInP/GaInAs/Ge solar cell. According to experiment result, the Pmm of solar cell was increased from 1.54 W/cm2 to 1.88 W/cm2. The η of solar cell was increased from 32% to 34.1% separately that compared with the concentrating photovoltaic system which without the second stage concentrator at the same concentration ratio(150X)

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