scholarly journals In-line measurement of absorbed solar irradiance using nanofluids

2021 ◽  
Vol 2116 (1) ◽  
pp. 012118
Author(s):  
E Zanetti ◽  
A Berto ◽  
M Meneghetti ◽  
D Del Col
Keyword(s):  
Solar Radiation ◽  
Solar Irradiance ◽  
Absorption Rate ◽  
Optical Behaviour ◽  
Carbon Nanohorns ◽  
Novel Technique ◽  
Line Measurement ◽  
Combined Use ◽  
Single Wall Carbon Nanohorns ◽  
Solar Receiver

Abstract In this paper a novel technique for the in-line evaluation of the absorption rate of solar radiation by nanofluids in a volumetric solar receiver is presented. This method allows to experimentally investigate the optical behaviour of a nanofluid when circulating in a volumetric solar receiver under non-concentrated solar irradiance and it is based on the combined use of pyranometers. This technique is used in the present work to study the absorption capability of a Single-Wall-Carbon-NanoHorns (SWCNHs) based nanofluid. From the experiments, it can be seen that after some hours of circulation, the absorption rate of the nanofluid decreases, due to a loss of nanoparticles in the suspension.

Investigation of nanofluids circulating in a volumetric solar receiver

2020 ◽  
pp. 1-39
Author(s):  
Emanuele Zanetti ◽  
Simone Dugaria ◽  
Francesca Biscaglia ◽  
Filippo Agresti ◽  
Laura Fedele ◽  
...  
Keyword(s):  
Optical Properties ◽  
Solar Radiation ◽  
Ad Hoc ◽  
Low Cost ◽  
Absorption Efficiency ◽  
Limited Information ◽  
Carbon Nanohorns ◽  
Novel Approach ◽  
Experimental Apparatus ◽  
Single Wall Carbon Nanohorns

Abstract Single-Wall-Carbon-Nanohorns (SWCNHs) based nanofluids have been proven to be promising media for the direct absorption of solar radiation due to their favourable optical properties and potential low cost. Still, their stability in real working conditions is an open issue because they have been studied mainly under stagnant conditions while limited information is available on the performance of these nanofluids during circulation in real systems. In the present work, the optical behaviour of SWCNHs based nanofluids has been investigated with the aim of detecting possible effects of circulation and exposure to radiation, avoiding other effects such as thermal instability. An ad-hoc experimental apparatus has been realized to check the stability of the circulating fluids in-situ using a novel approach based on the use of pyranometers. Three suspensions are tested, two are surfactant-stabilized and one is based on pre-oxidised and functionalised SWCNHs. Efficiency values higher than 90 % were measured for more than 65 hours of circulation. The effects of fluid circulation and exposure to solar radiation have been addressed, finding that the absorption efficiency decreases during tests due to the degradation of the optical properties and the nanofluid circulation is the main responsible for such degradation.

scholarly journals Thermal comfort in winter incorporating solar radiation effects at high altitudes and performance of improved passive solar design—Case of Lhasa

2020 ◽  
Author(s):  
Lingjiang Huang ◽  
Jian Kang
Keyword(s):  
Solar Radiation ◽  
Thermal Comfort ◽  
Energy Saving ◽  
Solar Irradiance ◽  
Indoor Environment ◽  
Thermal Mass ◽  
High Altitudes ◽  
Energy Saving Potential ◽  
Environment Control ◽  
Passive Solar

AbstractThe solar incidence on an indoor environment and its occupants has significant impacts on indoor thermal comfort. It can bring favorable passive solar heating and can result in undesired overheating (even in winter). This problem becomes more critical for high altitudes with high intensity of solar irradiance, while received limited attention. In this study, we explored the specific overheating and rising thermal discomfort in winter in Lhasa as a typical location of a cold climate at high altitudes. First, we evaluated the thermal comfort incorporating solar radiation effect in winter by field measurements. Subsequently, we investigated local occupant adaptive responses (considering the impact of direct solar irradiance). This was followed by a simulation study of assessment of annual based thermal comfort and the effect on energy-saving potential by current solar adjustment. Finally, we discussed winter shading design for high altitudes for both solar shading and passive solar use at high altitudes, and evaluated thermal mass shading with solar louvers in terms of indoor environment control. The results reveal that considerable indoor overheating occurs during the whole winter season instead of summer in Lhasa, with over two-thirds of daytime beyond the comfort range. Further, various adaptive behaviors are adopted by occupants in response to overheating due to the solar radiation. Moreover, it is found that the energy-saving potential might be overestimated by 1.9 times with current window to wall ratio requirements in local design standards and building codes due to the thermal adaption by drawing curtains. The developed thermal mass shading is efficient in achieving an improved indoor thermal environment by reducing overheating time to an average of 62.2% during the winter and a corresponding increase of comfort time.

Obtainable Method of Measuring the Solar Radiant Flux Based on Silicone Photodiode Element

2016 ◽  
Vol 824 ◽  
pp. 477-484 ◽  
Author(s):  
Miroslav Čekon ◽  
Richard Slávik ◽  
Peter Juras
Keyword(s):  
Solar Radiation ◽  
Solar Irradiance ◽  
Climate Science ◽  
Radiant Flux ◽  
Silicon Photodiode ◽  
Building Science ◽  
Solar Instruments ◽  
Solar Radiation Exposure ◽  
Building Physics

Solar radiation exposure and its monitoring does have not only the importance for climate science and meteorology however is equally of highly relevant use for the field of Building Science as primarily those of analyzing thermal aspects in building physics. Here the measuring of solar irradiance by means of well-established solar instruments can be applied whose advances have been undergoing steep progress. Currently, a silicon photodiode element, as a truly obtainable form, may have a feasible exploitation in the field of building applications concerning the solar radiant flux quantifying. It represents a small optoelectronic element and has a several exploitable advantages. The paper presents a perspective alternative to monitor solar irradiance. Own measurement assembly is proposed and introduced. Initial in-situ measurements are performed and final comparability with existing commercial solar instruments is presented. An obtained correlation with existing types demonstrates its applicability to the field of building science and solar energy.

Effect of Functional Groups at Hole Edges on Cisplatin Release from Inside Single-Wall Carbon Nanohorns

2006 ◽  
Vol 110 (11) ◽  
pp. 5773-5778 ◽  
Author(s):  
Kumiko Ajima ◽  
Masako Yudasaka ◽  
Alan Maigné, ◽  
Jin Miyawaki ◽  
Sumio Iijima
Keyword(s):  
Functional Groups ◽  
Single Wall Carbon ◽  
Carbon Nanohorns ◽  
Single Wall Carbon Nanohorns

Innovative Volumetric Solar Receiver Micro-Design Based on Numerical Predictions

2015 ◽  
Author(s):  
Raffaele Capuano ◽  
Thomas Fend ◽  
Bernhard Hoffschmidt ◽  
Robert Pitz-Paal
Keyword(s):  
Solar Radiation ◽  
Energy Demand ◽  
Large Scale ◽  
Solar Power ◽  
Numerical Models ◽  
Numerical Predictions ◽  
Proper Design ◽  
Global Increase ◽  
Solar Power Tower ◽  
Solar Receiver

Due to the continuous global increase in energy demand, Concentrated Solar Power (CSP) represents an excellent alternative, or add-on to existing systems for the production of energy on a large scale. In some of these systems, the Solar Power Tower plants (SPT), the conversion of solar radiation into heat occurs in certain components defined as solar receivers, placed in correspondence of the focus of the reflected sunlight. In a particular type of solar receivers, defined as volumetric, the use of porous materials is foreseen. These receivers are characterized by a porous structure called absorber. The latter, hit by the reflected solar radiation, transfers the heat to the evolving fluid, generally air subject to natural convection. The proper design of these elements is essential in order to achieve high efficiencies, making such structures extremely beneficial for the overall performances of the energy production process. In the following study, a parametric analysis and an optimized characterization of the structure have been performed with the use of self-developed numerical models. The knowledge and results gained through this study have been used to define an optimization path in order to improve the absorber microstructure, starting from the current in-house state-of-the-art technology until obtaining a new advanced geometry.

scholarly journals Direct Solar Radiation and Atmospheric Turbidity in Mikołajki in the Years 1971–1980 and 1991–2000

2009 ◽  
Vol 2 (1) ◽  
pp. 19-33
Author(s):  
Joanna Uscka-Kowalkowska
Keyword(s):  
Solar Radiation ◽  
Solar Irradiance ◽  
Direct Solar Radiation ◽  
Spectral Structure ◽  
Solar Constant ◽  
Air Masses ◽  
Atmospheric Turbidity ◽  
The Earth

Abstract The present study deals with the changing amount of incoming direct solar radiation and the optical state of the atmosphere in Mikołajki in the years 1971-1980 and 1991-2000. The highest level of solar irradiance in these two decades occurred on 23rd June 1977 and amounted to 1043.9 W·m-2. Compared to the first decade analysed, the percentage of the solar constant reaching the Earth in the second decade was higher. The spectral structure of the radiation also changed - the share of the shortest waves (λ<525 nm) increased, whereas the amount of waves with a wavelength of 710 nm or more decreased. In both study periods the annual course of solar extinction (expressed in terms of Linke’s turbidity factor) turned out to have been typical, with the highest values in summer and the lowest in winter. In the years 1991-2000, in all seasons, a lower atmospheric turbidity was observed in comparison with the years 1971-1980. The atmospheric turbidity was also analysed with relation to the air masses. In both decades in question the lowest turbidity occurred in arctic air masses and the highest in tropical air masses. An improved optical state of the atmosphere was observed in all considered air masses, though the biggest decrease in turbidity was found in polar air masses, particularly in the polar maritime old air (TLAM2 dropped by 0.75) and polar continental air (by 0.70).

scholarly journals Economical and efficient technique for a static localized maximum sun lux determination

2019 ◽  
Vol 10 (2) ◽  
pp. 777
Author(s):  
Ahmed H. Ali ◽  
Adel S. Nada ◽  
Ahmed S. Shalaby
Keyword(s):  
Solar Cell ◽  
Solar Energy ◽  
Solar Irradiance ◽  
Field Measurements ◽  
Fine Tuning ◽  
Efficient Technique ◽  
Irradiance Measurement ◽  
Novel Technique ◽  
Site Field ◽  
Optimal Values

<span>Solar energy is one of the most promising renewable sources that is currently being used worldwide to contribute for meeting rising demands. In this paper solar irradiance measurement will experimentally carried out in two different regions in Egypt; Cairo and Luxor cities. This paper proposes a simple solar lux measurement using a light dependent resistor (LDR) with an arduino kit. This technique is based on two approaches which are coarse and fine maximum sun lux determination. This is based on the predetermined 26<sup>0</sup> vertical slop of the LDR. Coarse tuning determines one of the reach sun lux quarter (90<sup>0</sup>) of horizontal quad. The fine tuning allocates the optimized 10<sup>0</sup> in which; the maximum sun lux can be obtained. The optimal values of sun lux were found between the (90<sup>o</sup>–180<sup>o</sup>) quarter. This study confirms that the narrow ten degrees (95<sup>o</sup>-105<sup>o</sup>) are the optimized static sun lux extraction for the two site field measurements. This novel technique can be used for locating the angle of best installations for the solar cell at which maximum solar energy can be extracted. </span>

scholarly journals EFFECT OF TEMPERATURE, HUMIDITY AND IRRADIANCE ON SOLAR POWER GENERATION

2021 ◽  
Vol 26 (4) ◽  
pp. 113-119
Author(s):  
FRANK ONAIFO ◽  
AKPOFURE ALEXANDER OKANDEJI ◽  
OLAMIDE AJETUNMOBI ◽  
DAVID BALOGUN
Keyword(s):  
Power Generation ◽  
Solar Cells ◽  
Solar Cell ◽  
Solar Radiation ◽  
Solar Irradiance ◽  
Solar Power ◽  
Corrosion Process ◽  
Effect Of Temperature ◽  
Photovoltaic Solar Cell ◽  
Solar Power Generation

This paper studies the effect of temperature, humidity and irradiance on the power generated by a photovoltaic solar cell. This was achieved using pyranometer for determining the solar radiation, wet and dry thermometer for measuring humidity, and digital multimeter for voltage and current measurement. The result of the study show that power generation increases with increase of solar irradiance. Additionally, changes of humidity level and temperature do not significantly affect solar power generation. Furthermore, it was also observed that high temperatures and higher humidity levels accelerate the corrosion process on the solar cells which reduces the efficiency of the cells.

Unique magnetism observed in single-wall carbon nanohorns

2001 ◽  
Vol 73 (3) ◽  
pp. 281-285 ◽  
Author(s):  
S. Bandow ◽  
F. Kokai ◽  
K. Takahashi ◽  
M. Yudasaka ◽  
S. Iijima
Keyword(s):  
Single Wall Carbon ◽  
Carbon Nanohorns ◽  
Single Wall Carbon Nanohorns
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