scholarly journals A New Strategy for Accurately PredictingI-VElectrical Characteristics of PV Modules Using a Nonlinear Five-Point Model

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Sakaros Bogning Dongue ◽  
Donatien Njomo ◽  
Lessly Ebengai
Keyword(s):  
Experimental Data ◽  
Nonlinear Effect ◽  
Solar Irradiance ◽  
Great Accuracy ◽  
Operating Conditions ◽  
Point Model ◽  
Photovoltaic Modules ◽  
Pv Modules ◽  
Good Comparison ◽  
New Strategy

This paper presents the modelling of electricalI-Vresponse of illuminated photovoltaic crystalline modules. As an alternative method to the linear five-parameter model, our strategy uses advantages of a nonlinear analytical five-point model to take into account the effects of nonlinear variations of current with respect to solar irradiance and of voltage with respect to cells temperature. We succeeded in this work to predict with great accuracy theI-Vcharacteristics of monocrystalline shell SP75 and polycrystalline GESOLAR GE-P70 photovoltaic modules. The good comparison of our calculated results to experimental data provided by the modules manufacturers makes it possible to appreciate the contribution of taking into account the nonlinear effect of operating conditions data onI-Vcharacteristics of photovoltaic modules.

scholarly journals An Improved Nonlinear Five-Point Model for Photovoltaic Modules

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Sakaros Bogning Dongue ◽  
Donatien Njomo ◽  
Lessly Ebengai
Keyword(s):  
Mathematical Model ◽  
Solar Irradiance ◽  
Nonlinear Effects ◽  
Photovoltaic Module ◽  
Economic Returns ◽  
Point Model ◽  
Simulation Tools ◽  
Photovoltaic Modules ◽  
Pv Panel ◽  
Pv Modules

This paper presents an improved nonlinear five-point model capable of analytically describing the electrical behaviors of a photovoltaic module for each generic operating condition of temperature and solar irradiance. The models used to replicate the electrical behaviors of operating PV modules are usually based on some simplified assumptions which provide convenient mathematical model which can be used in conventional simulation tools. Unfortunately, these assumptions cause some inaccuracies, and hence unrealistic economic returns are predicted. As an alternative, we used the advantages of a nonlinear analytical five-point model to take into account the nonideal diode effects and nonlinear effects generally ignored, which PV modules operation depends on. To verify the capability of our method to fit PV panel characteristics, the procedure was tested on three different panels. Results were compared with the data issued by manufacturers and with the results obtained using the five-parameter model proposed by other authors.

Parallel Multi-Cycle LES of an Optical Pent-Roof DISI Engine Under Motored Operating Conditions

2017 ◽  
Author(s):  
Noah Van Dam ◽  
Wei Zeng ◽  
Magnus Sjöberg ◽  
Sibendu Som
Keyword(s):  
Experimental Data ◽  
Direct Injection ◽  
Operating Conditions ◽  
New Strategy ◽  
Long Time ◽  
Order Of Magnitude ◽  
Structure Index ◽  
Number Of Cycles ◽  
The Many ◽  
Direct Injection Spark Ignition

The use of Large-eddy Simulations (LES) has increased due to their ability to resolve the turbulent fluctuations of engine flows and capture the resulting cycle-to-cycle variability. One drawback of LES, however, is the requirement to run multiple engine cycles to obtain the necessary cycle statistics for full validation. The standard method to obtain the cycles by running a single simulation through many engine cycles sequentially can take a long time to complete. Recently, a new strategy has been proposed by our research group to reduce the amount of time necessary to simulate the many engine cycles by running individual engine cycle simulations in parallel. With modern large computing systems this has the potential to reduce the amount of time necessary for a full set of simulated engine cycles to finish by up to an order of magnitude. In this paper, the Parallel Perturbation Methodology (PPM) is used to simulate up to 35 engine cycles of an optically accessible, pent-roof Direct-injection Spark-ignition (DISI) engine at two different motored engine operating conditions, one throttled and one un-throttled. Comparisons are made against corresponding sequential-cycle simulations to verify the similarity of results using either methodology. Mean results from the PPM approach are very similar to sequential-cycle results with less than 0.5% difference in pressure and a magnitude structure index (MSI) of 0.95. Differences in cycle-to-cycle variability (CCV) predictions are larger, but close to the statistical uncertainty in the measurement for the number of cycles simulated. PPM LES results were also compared against experimental data. Mean quantities such as pressure or mean velocities were typically matched to within 5–10%. Pressure CCVs were under-predicted, mostly due to the lack of any perturbations in the pressure boundary conditions between cycles. Velocity CCVs for the simulations had the same average magnitude as experiments, but the experimental data showed greater spatial variation in the root-mean-square (RMS). Conversely, circular standard deviation results showed greater repeatability of the flow directionality and swirl vortex positioning than the simulations.

scholarly journals Comparative study on different types of photovoltaic modules under outdoor operating conditions in Minna, Nigeria

2018 ◽  
Vol 6 (1) ◽  
pp. 35
Author(s):  
Joel A. Ezenwora ◽  
David O. Oyedum ◽  
Paulinus E. Ugwuoke
Keyword(s):  
Measured Data ◽  
Operating Conditions ◽  
Performance Variables ◽  
Photovoltaic Modules ◽  
Pv Module ◽  
Pv Modules ◽  
Different Types ◽  
Metal Support ◽  
One Year ◽  
Module Performance

There is need to always obtain the realistic outdoor performance variables of Photovoltaic (PV) module in a location for efficient PV power system sizing and design. Outdoor performance evaluation was carried out on three types of commercially available silicon PV modules rated 10 W each, using CR1000 software-based Data Acquisition System (DAS). The PV modules under test and meteorological sensors were installed on a metal support structure at the same test plane.The data monitoring was from 08.00 to 18.00 hours each day continuously for a period of one year, from December 2014 to November 2015. Maximum values of module efficiencies of 5.86% and 10.91% for the monocrystalline and polycrystalline modules were respectively recorded at irradiance of 375 W/m2, while the amorphous efficiency peaked at 3.61 % with irradiance of 536.5 W/m2. At 1000 W/m2 the efficiencies reduced to 3.30 %, 6.20 % and 2.25 % as against manufacturer’s specifications of 46 %, 48 % and 33 % for the monocrystalline, polycrystalline and amorphous modules respectively. The maximum power output achieved for the modules at irradiance of 1000 W/m2 were 0.711 W, 1.323 W and 0.652 W for the monocrystalline, polycrystalline and amorphous PV modules, respectively. Accordingly, Module Performance Ratios for the PV modules investigated were 0.07, 0.13 and 0.07, respectively. The rate of variation of module response variables with irradiance and temperature was determined using a linear statistical model given as Y= a + bHg+ c Tmod. The approach performed creditably when compared with measured data.

scholarly journals Possibilities of Using Semi-Transparent Photovoltaic Modules on Rooftops of Greenhouses for Covering Their Energy Needs

2015 ◽  
Vol 4 (1) ◽  
pp. 90
Author(s):  
John Vourdoubas
Keyword(s):  
Solar Irradiance ◽  
Energy Use ◽  
Heat Pumps ◽  
Photovoltaic Modules ◽  
First Case ◽  
Energy Needs ◽  
Pv Modules ◽  
The Government ◽  
Commercial Applications ◽  
Solid Biomass

Semi-transparent photovoltaic cells allow the transmittance of solar irradiance through them and they have been used in building’s skylights and facades. Their use on rooftops of greenhouses can result in electricity generation which can cover part or all of their energy needs without affecting the growth of the plants. This also results in the decrease of cooling requirements during the summer since less solar irradiance is entering the greenhouse and lower CO2 emissions due to energy use in it. However, their current prices are high compared with the prices of opaque PV cells. The purpose of the present work is to investigate the possible use of semi-transparent PV modules placed on the roof of energy intensive greenhouses in Crete-Greece in order to cover their energy requirements and sell the surplus electricity into the grid. Two different cases have been studied where greenhouses of 1,000 m2 each cover their high heating needs using heat pumps and solid biomass. PV modules of 42.5 KWp can be placed on their roofs covering slightly less than 50 % of their surface allowing enough solar irradiance to enter the greenhouse. In the first case the generated electricity can cover more than 80 % of total energy needs and in the second all the energy needs offering the possibility of selling the surplus electricity to the grid. However, the current high prices of semi-transparent PVs do not favour their use by farmers since their installation costs are high. Future financial support from the government could increase their attractiveness for commercial applications in greenhouses.

scholarly journals A Study of Developing a Prediction Equation of Electricity Energy Output via Photovoltaic Modules

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1503
Author(s):  
Minsu Kim ◽  
Hongmyeong Kim ◽  
Jae Hak Jung
Keyword(s):  
Experimental Data ◽  
Real Time ◽  
Air Temperature ◽  
Temperature Difference ◽  
Prediction Accuracy ◽  
Prediction Equation ◽  
Energy Output ◽  
Photovoltaic Modules ◽  
Mean Error ◽  
Pv Module

Various equations are being developed and applied to predict photovoltaic (PV) module generation. Currently, quite diverse methods for predicting module generation are available, with most equations showing accuracy with ≤5% error. However, the accuracy can be determined only when the module temperature and the value of irradiation that reaches the module surface are precisely known. The prediction accuracy of outdoor generation is actually extremely low, as the method for predicting outdoor module temperature has extremely low accuracy. The change in module temperature cannot be predicted accurately because of the real-time change of irradiation and air temperature outdoors. Calculations using conventional equations from other studies show a mean error of temperature difference of 4.23 °C. In this study, an equation was developed and verified that can predict the precise module temperature up to 1.64 °C, based on the experimental data obtained after installing an actual outdoor module.

scholarly journals Migration of Sn and Pb from Solder Ribbon onto Ag Fingers in Field-Aged Silicon Photovoltaic Modules

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Wonwook Oh ◽  
Seongtak Kim ◽  
Soohyun Bae ◽  
Nochang Park ◽  
Sung-Il Chan ◽  
...  
Keyword(s):  
Solar Cells ◽  
Galvanic Corrosion ◽  
Solar Irradiation ◽  
Photovoltaic Modules ◽  
Si Solar Cells ◽  
Test Conditions ◽  
Pv Modules ◽  
Moisture Condensation ◽  
Acceleration Test ◽  
Light Induced Plating

We investigated the migration of Sn and Pb onto the Ag fingers of crystalline Si solar cells in photovoltaic modules aged in field for 6 years. Layers of Sn and Pb were found on the Ag fingers down to the edge of the solar cells. This phenomenon is not observed in a standard acceleration test condition for PV modules. In contrast to the acceleration test conditions, field aging subjects the PV modules to solar irradiation and moisture condensation at the interface between the solar cells and the encapsulant. The solder ribbon releases Sn and Pb via repeated galvanic corrosion and the Sn and Pb precipitate on Ag fingers due to the light-induced plating under solar irradiation.

scholarly journals A Study of Optimal Specifications for Light Shelves with Photovoltaic Modules to Improve Indoor Comfort and Save Building Energy

2021 ◽  
Vol 18 (5) ◽  
pp. 2574
Author(s):  
Heangwoo Lee ◽  
Xiaolong Zhao ◽  
Janghoo Seo
Keyword(s):  
Energy Savings ◽  
Building Energy ◽  
Energy Performance ◽  
Building Energy Efficiency ◽  
Efficiency Change ◽  
Photovoltaic Modules ◽  
Heating And Cooling ◽  
Pv Module ◽  
Pv Modules ◽  
Indoor Comfort

Recent studies on light shelves found that building energy efficiency could be maximized by applying photovoltaic (PV) modules to light shelf reflectors. Although PV modules generate a substantial amount of heat and change the consumption of indoor heating and cooling energy, performance evaluations carried out thus far have not considered these factors. This study validated the effectiveness of PV module light shelves and determined optimal specifications while considering heating and cooling energy savings. A full-scale testbed was built to evaluate performance according to light shelf variables. The uniformity ratio was found to improve according to the light shelf angle value and decreased as the PV module installation area increased. It was determined that PV modules should be considered in the design of light shelves as their daylighting and concentration efficiency change according to their angles. PV modules installed on light shelves were also found to change the indoor cooling and heating environment; the degree of such change increased as the area of the PV module increased. Lastly, light shelf specifications for reducing building energy, including heating and cooling energy, were not found to apply to PV modules since PV modules on light shelf reflectors increase building energy consumption.

Modeling and Experimental Validation of the Effective Bulk Modulus of a Mixture of Hydraulic Oil and Air

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Hossein Gholizadeh ◽  
Doug Bitner ◽  
Richard Burton ◽  
Greg Schoenau
Keyword(s):  
Experimental Data ◽  
Bulk Modulus ◽  
Theoretical Models ◽  
Operating Conditions ◽  
Air Bubbles ◽  
Pressure Sensitivity ◽  
Hydraulic Oil ◽  
Effective Bulk Modulus ◽  
Experimental Apparatus ◽  
Major Factors

It is well known that the presence of entrained air bubbles in hydraulic oil can significantly reduce the effective bulk modulus of hydraulic oil. The effective bulk modulus of a mixture of oil and air as pressure changes is considerably different than when the oil and air are not mixed. Theoretical models have been proposed in the literature to simulate the pressure sensitivity of the effective bulk modulus of this mixture. However, limited amounts of experimental data are available to prove the validity of the models under various operating conditions. The major factors that affect pressure sensitivity of the effective bulk modulus of the mixture are the amount of air bubbles, their size and the distribution, and rate of compression of the mixture. An experimental apparatus was designed to investigate the effect of these variables on the effective bulk modulus of the mixture. The experimental results were compared with existing theoretical models, and it was found that the theoretical models only matched the experimental data under specific conditions. The purpose of this paper is to specify the conditions in which the current theoretical models can be used to represent the real behavior of the pressure sensitivity of the effective bulk modulus of the mixture. Additionally, a new theoretical model is proposed for situations where the current models fail to truly represent the experimental data.

Sign in / Sign up

Export Citation Format

Share Document