Thermal model to quantify the impact of sub-bandgap reflectance on operating temperature of fielded PV modules

Solar Energy ◽  
2021 ◽  
Vol 220 ◽  
pp. 246-250
Author(s):  
Jonathan L. Bryan ◽  
Timothy J. Silverman ◽  
Michael G. Deceglie ◽  
Zachary C. Holman
Keyword(s):  
Thermal Model ◽  
Operating Temperature ◽  
Pv Modules ◽  
The Impact

scholarly journals Experimental Effect of the Impact of Stagnant Water on Solar Modules

2020 ◽  
Vol 9 (3) ◽  
pp. 2095-2100
Keyword(s):  
Experimental Study ◽  
Power Output ◽  
Output Voltage ◽  
Operating Temperature ◽  
Output Current ◽  
Stagnant Water ◽  
Pv Module ◽  
Pv Modules ◽  
Experimental Effect ◽  
The Impact

In this research, an experimental study of the impact of stagnant water on solar modules is investigated. Two different experiments using two identical photovoltaic (PV) modules S1 and S2 were used for the study. In the first experiment, the PV module S1 was covered with stagnant water and the second PV module was unshielded with water. In the second experiment, the PV modules were swapped with S2 covered with stagnant water and S1 unshielded with water. The experiments were carried out under normal operating temperature of PV cells at the Department of Electrical Engineering, University of Nigeria, Nsukka on latitude 6:52 degrees north, longitude 7:23 degrees. Results obtained from the first experiment show that the efficiency and power output of S1 PV module decreased by 9.3% and 8.0% respectively when compared with that of S2 PV module. In the case of output voltage and current, it was found that shielding of PV module S1 with stagnant water caused an increase in the output voltage by 1.93% and a decrease in the output current by 10.26%. In the second experiment, the efficiency and Output power of PV module S2 decreased by 9.21% and 8.18% respectively when compared with the unshielded PV module S1. In the case of voltage and current, it was found that shielding of PV module S2 with stagnant water caused an increase in the Output voltage by 1.63% and decrease in the output current by 10.91%.

Truck Tire Operating Temperatures on Flat and Curved Test Surfaces

2005 ◽  
Vol 33 (3) ◽  
pp. 156-178 ◽  
Author(s):  
T. J. LaClair ◽  
C. Zarak
Keyword(s):  
Flat Surface ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Load Pressure ◽  
Truck Tire ◽  
Endurance Testing ◽  
Operating Temperatures ◽  
The Impact ◽  
Tread Rubber ◽  
Cylindrical Test

Abstract Operating temperature is critical to the endurance life of a tire. Fundamental differences between operations of a tire on a flat surface, as experienced in normal highway use, and on a cylindrical test drum may result in a substantially higher tire temperature in the latter case. Nonetheless, cylindrical road wheels are widely used in the industry for tire endurance testing. This paper discusses the important effects of surface curvature on truck tire endurance testing and highlights the impact that curvature has on tire operating temperature. Temperature measurements made during testing on flat and curved surfaces under a range of load, pressure and speed conditions are presented. New tires and re-treaded tires of the same casing construction were evaluated to determine the effect that the tread rubber and pattern have on operating temperatures on the flat and curved test surfaces. The results of this study are used to suggest conditions on a road wheel that provide highway-equivalent operating conditions for truck tire endurance testing.

Расчетные методы оценки ударной вязкости сварных элементов с трещинами

2020 ◽  
Vol 44 (3) ◽  
pp. 22-36
Author(s):  
Keyword(s):  
Stress Intensity ◽  
Impact Strength ◽  
Welded Joints ◽  
Development Process ◽  
Welded Joint ◽  
Operating Temperature ◽  
Crack Development ◽  
Heterogeneous Structure ◽  
Critical Crack Length ◽  
The Impact

Практика показывает, что для сварных конструкций, эксплуатируемых в условиях Крайнего Севера необходимо уделять внимание работоспособности сварных соединений при низких температурах. Металл сварных соединений в процессе воздействия обработки изменяет свои свойства, снижается ударная вязкость, образуется гетерогенная структура с большой степенью разнозернистости. Чтобы оценивать и иметь возможность правильно контролировать термическое воздействие и последствия сварочного процесса, требуется решить задачу аналитического определения ударной вязкости для всех зон сварного соединения. В настоящей статье представлен инженерный метод оценки ударной вязкости, применимый для любой зоны сварного соединения, в которой имеется острый или особый концентратор напряжений – трещина. Разработанный аналитический метод расчета ударной вязкости отражает качественную и количественную картину взаимосвязи структурно-механических характеристик и работы развития трещины в диапазоне температур 77…300 К. Предложенная схематизация зависимости критического коэффициента интенсивности напряжений от температуры позволила найти коэффициенты, характеризующие свойства материала, и выполнить расчеты изменения предела текучести и предела прочности от температуры эксплуатации. Построены графики зависимости работы развития трещины от температуры эксплуатации для сталей 15ГС и 17ГС, сравнение которых с экспериментальными данными показывает удовлетворительное согласование. Найдено, что при напряжениях предела выносливости отношение работы развития трещины к критической длине трещины постоянно, не зависит от температуры и для сталей 15ГС и 17ГС равно около 10. Ключевые слова: ударная вязкость, работа разрушения, коэффициент интенсивности напряжений, трещина, феррито-перлитная сталь, зона термического влияния. For welded structures under operation in the Far North, attention must be paid to the performance of welded joints at low temperatures. The properties of metal of welded joints are changed in the process of treatment, its toughness decreases, and a heterogeneous structure with a large range of different grain sizes is formed. In order to evaluate and be able to correctly control the thermal effect and the consequences of the welding process, it is necessary to solve the problem of analytical determination of impact strength for all zones of the welded joint. The paper presents an engineering method for evaluation of the impact strength applicable to any area of the welded joint in which there is a sharp or super sharp stress concentrator – a crack. The developed analytical method for calculating the impact strength reflects a qualitative and quantitative codependency of structural and mechanical characteristics and the process of crack development in the temperature range of 77–300 K. The proposed schematization of dependence of the critical coefficient of stress intensity on the temperature made it possible to find coefficients characterizing the properties of the material and to perform calculations of changes in yield strength and tensile strength on operating temperature. Graphs of the crack development process dependency on the operating temperature for 15ГС and 17ГС steels were constructed, and their comparison with experimental data displays satisfactory agreement. It was found that at endurance limit stresses, the ratio of the crack development process to the critical crack length is constant, non-dependent on temperature, and is equal to 10 for 15ГС and 17ГС steels. Keywords: impact strength, fracture work, stress intensity factor, crack, ferrite-pearlite steel, heat affected zone, steel tempering.

scholarly journals Modeling of Photovoltaic Module Using the MATLAB

2019 ◽  
Vol 9 ◽  
pp. 59-69
Author(s):  
Alok Dhaundiyal ◽  
Divine Atsu
Keyword(s):  
Standard Test ◽  
Electrical Performance ◽  
Photovoltaic Module ◽  
Solar Pv ◽  
Pv Module ◽  
Proposed Model ◽  
Current Voltage ◽  
Pv Modules ◽  
The Impact ◽  
The Mathematical Model

This paper presents the modeling and simulation of the characteristics and electrical performance of photovoltaic (PV) solar modules. Genetic coding is applied to obtain the optimized values of parameters within the constraint limit using the software MATLAB. A single diode model is proposed, considering the series and shunt resistances, to study the impact of solar irradiance and temperature on the power-voltage (P-V) and current-voltage (I-V) characteristics and predict the output of solar PV modules. The validation of the model under the standard test conditions (STC) and different values of temperature and insolation is performed, as well as an evaluation using experimentally obtained data from outdoor operating PV modules. The obtained results are also subjected to comply with the manufacturer’s data to ensure that the proposed model does not violate the prescribed tolerance range. The range of variation in current and voltage lies in the domain of 8.21 – 8.5 A and 22 – 23 V, respectively; while the predicted solutions for current and voltage vary from 8.28 – 8.68 A and 23.79 – 24.44 V, respectively. The measured experimental power of the PV module estimated to be 148 – 152 W is predicted from the mathematical model and the obtained values of simulated solution are in the domain of 149 – 157 W. The proposed scheme was found to be very effective at determining the influence of input factors on the modules, which is difficult to determine through experimental means.

Natural convection effects on thermal ignition in a porous medium. II. Lumped thermal model-I

1990 ◽  
Vol 429 (1877) ◽  
pp. 555-567 ◽  
Keyword(s):  
Thermal Conductivity ◽  
Rayleigh Number ◽  
Thermal Model ◽  
Lewis Number ◽  
Reaction Model ◽  
Heat Of Reaction ◽  
Bifurcation Diagrams ◽  
Diffusion Term ◽  
The Impact ◽  
Species Diffusion

In this paper, we examine the disappearance of criticality, ignition locus and bifurcation diagrams of temperature against Rayleigh number of a one-dimensional diffusion-convection-reaction model with the assumption of infinite thermal conductivity and zero species diffusivity. The predictions of this model are compared with those of the Semenov model to determine the impact of the species diffusion term. It is shown that for large values of the Rayleigh number (R* ≫ 1), the ignition locus may be expressed in a parametric form B Ls = t /ln t + t /( t - 1) (1 < t ≼ 3.4955), ψ / R * = ( B Ls ) 2 (( t - 1)/ t ) exp{ - B Ls + B Ls / t } ln t , where B is the heat of reaction parameter, ψ is the Semenov number and Ls is a (modified) Lewis number. Criticality is found to disappear at B Ls = 4.194. When these results are compared with those of the Semenov model, it is found that neglecting the species diffusion term gives conservative approximations to the ignition locus, and criticality boundary. It is found that the lumped thermal model-I has five different types of bifurcation diagrams of temperature against Rayleigh number (single­-valued, isola, inverse S , mushroom, inverse S + isola). These diagrams are qualitatively identical to the bifurcation diagrams of temperature against flow rate for the forced convection problem under the assumption of infinite thermal conductivity and zero species diffusivity.

scholarly journals Assessment of the Operating Temperature of Crystalline PV Modules Based on Real Use Conditions

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Giuseppina Ciulla ◽  
Valerio Lo Brano ◽  
Vincenzo Franzitta ◽  
Marco Trapanese
Keyword(s):  
Operating Temperature ◽  
Maximum Power ◽  
Electricity Production ◽  
Electrical Behaviour ◽  
Weather Variables ◽  
Actual Performance ◽  
Photovoltaic Panels ◽  
New Correlation ◽  
Pv Modules

Determining the operating temperatureTcof photovoltaic panelsPVis important in evaluating the actual performance of these systems. In the literature, different correlations exist, in either explicit or implicit forms, which often do not account for the electrical behaviour of panels; in this way, estimatingTcis based only on the passive behaviour of thePV. In this paper, the authors propose a new implicit correlation that takes into account the standard weather variables and the electricity production regimes of aPVpanel in terms of the proximity to the maximum power points. To validate its reliability, the new correlation was tested on two different PV panels (Sanyo and Kyocera panels) and the results were compared with values obtained from other common correlations already available in the literature. The data show that the quality of the new correlation drastically improves the estimation of the photovoltaic operating temperature.

Climate-Specific Thermal Model Coefficients for c-Si and Thin-Film PV Modules

2017 ◽  
Author(s):  
Ashwini Pavgi ◽  
Joseph Kuitche ◽  
Jaewon Oh ◽  
GovindaSamy TamizhMani
Keyword(s):  
Thin Film ◽  
Thermal Model ◽  
Pv Modules

From Chip to Cooling Tower Data Center Modeling: Chip Leakage Power and its Impact on Cooling Infrastructure Energy Efficiency

2011 ◽  
Author(s):  
Thomas J. Breen ◽  
Ed J. Walsh ◽  
Jeff Punch ◽  
Amip J. Shah ◽  
Cullen E. Bash ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Power Consumption ◽  
Data Center ◽  
Heat Dissipation ◽  
Linear Models ◽  
Operating Temperature ◽  
Leakage Power ◽  
Operating Conditions ◽  
Operating Temperatures ◽  
The Impact

The power consumption of the chip package is known to vary with operating temperature, independently of the workload processing power. This variation is commonly known as chip leakage power, typically accounting for ∼10% of total chip power consumption. The influence of operating temperature on leakage power consumption is a major concern for the IT industry for design optimization where IT system power densities are steadily increasing and leakage power expected to account for up to ∼50% of chip power in the near future associated with the reducing package size. Much attention has been placed on developing models of the chip leakage power as a function of package temperature, ranging from simple linear models to complex super-linear models. This knowledge is crucial for IT system designers to improve chip level energy efficiency and minimize heat dissipation. However, this work has been focused on the component level with little thought given to the impact of chip leakage power on entire data center efficiency. Studies on data center power consumption quote IT system heat dissipation as a constant value without accounting for the variance of chip power with operating temperature due to leakage power. Previous modeling techniques have also omitted this temperature dependent relationship. In this paper we discuss the need for chip leakage power to be included in the analysis of holistic data center performance. A chip leakage power model is defined and its implementation into an existing multi-scale data center energy model is discussed. Parametric studies are conducted over a range of system and environment operating conditions to evaluate the impact of varying degrees of chip leakage power. Possible strategies for mitigating the impact of leakage power are also illustrated in this study. This work illustrates that when including chip leakage power in the data center model, a compromise exists between increasing operating temperatures to improve cooling infrastructure efficiency and the increase in heat load at higher operating temperatures due to leakage power.

scholarly journals Experiment-based Study on the Impact of Soiling on PV System’s Performance

2016 ◽  
Vol 6 (2) ◽  
pp. 810
Author(s):  
Wan Juzaili Jamil ◽  
Hasimah Abdul Rahman ◽  
Kyairul Azmi Baharin
Keyword(s):  
Tropical Climate ◽  
System Efficiency ◽  
Worst Case ◽  
Solar Photovoltaics ◽  
Pv Module ◽  
Pv Modules ◽  
Dust Loading ◽  
Module Performance ◽  
The Impact ◽  
Full Day

Soiling refers to the accumulation of dust on PV modules which plays a small but significant role in degrading solar photovoltaics system efficiency. Its effect cannot be generalized because the severity is location and environment dependent. Currently, there are limited studies available on the soiling effect in the hot and humid Malaysian tropical climate. This paper presents an experimental-based approach to investigate the effect of soiling on PV module performance in a tropical climate. The experiment involved a full day exposure of a polycrystalline PV module in the outdoors with accelerated artificial dust loading and an indoor experiment for testing variable dust dimensions. The findings show that for the worst case, the module’s output can be reduced by as much as 20%.

Sign in / Sign up

Export Citation Format

Share Document