scholarly journals A New Dynamic Model to Predict Transient and Steady State PV Temperatures Taking into Account the Environmental Conditions

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 2 ◽  
Author(s):  
Socrates Kaplanis ◽  
Eleni Kaplani
Keyword(s):  
Steady State ◽  
Environmental Conditions ◽  
Solar Irradiance ◽  
Model Performance ◽  
Transient Temperature ◽  
Temperature Profiles ◽  
Time Constants ◽  
Proposed Model ◽  
Pv Cell ◽  
Transient And Steady State

Photovoltaic (PV) cell and module temperature profiles, Tc and Tpv, respectively, developed under solar irradiance were predicted and measured both at transient and steady state conditions. The predicted and measured Tc or Tpv covered both a bare c-Si PV cell, by SOLARTEC, at laboratory conditions using a solar light simulator, as well as various c-Si and pc-Si modules (SM55, Bioenergy 195W, Energy Solutions 125W) operating in field conditions. The time constants, τ, of the Tc and Tpv profiles were determined by the proposed model and calculated using the experimentally obtained profiles for both the bare PV cell and PV modules. For model validation, the predicted steady state and transient temperature profiles were compared with experimental ones and also with those generated from other models. The effect of the ambient temperature, Ta, wind speed, vw, and the solar irradiance, IT, on the model performance, as well as of the mounting geometries, was investigated and incorporated in the prediction model. The predicted temperatures had the best matching to the measured ones in comparison to those from six other models. The model developed is applicable to any geographical site and environmental conditions.

Numerical Study of Transient and Steady-State Anisotropic Cylindrical Pin Fin Thermal Behavior

2019 ◽  
Vol 11 (3) ◽  
Author(s):  
Imane Aslib ◽  
Hamid Hamza ◽  
Nisrine Hanchi ◽  
Jawad Lahjomri ◽  
Abdelaziz Oubarra
Keyword(s):  
Heat Conduction ◽  
Steady State ◽  
Thermal Behavior ◽  
Temperature Profile ◽  
Numerical Study ◽  
Numerical Code ◽  
Transient Temperature ◽  
Physical Parameters ◽  
Pin Fin ◽  
Transient And Steady State

This paper deals with the transient thermal analysis of two-dimensional cylindrical anisotropic pin fin that contains tip convection and subjected to a prescribed temperature at the fin base. The heat conduction equation contains a dual second-order derivation, which precludes solving the equation by direct application of common exact methods. Therefore, an appropriate canonical mapping is selected as a solution to cancel the dual derivation of temperature in the mapped equations. The alternating-direction implicit finite difference method (ADI) performs the integration of the mapped equations in the novel space, which involve a complicate geometry. Applying the inverse spatial transformation provides transient temperature profile in the real geometry for full-field configuration. The established numerical code has been validated successfully with the analytical solutions of the usual fins (orthotropic and isotropic). The anisotropy effect is investigated by means of various contour plots of the temperature profile as well as heat transfer rate from the fin base and the effectiveness for different parameters of study (kr/kz, krz/kz , and  Bir) in transient and steady-state heat conduction. The numerical code allows the study of the thermal behavior of anisotropic, orthotropic, and isotropic cylindrical pin fin according to the geometrical and physical parameters, as well as the thermal conditions to which the pin fin is subjected. A parametric study is performed in view to compare the thermal behavior of the various pin fin kinds submitted to the same conditions.

Nonlinear dynamic analysis of periodic ferroresonance based on a novel hysteresis approach

2016 ◽  
Vol 30 (09) ◽  
pp. 1650164 ◽  
Author(s):  
Mi Zou ◽  
Wen-Xia Sima ◽  
Ming Yang ◽  
Qing Yang ◽  
Licheng Li ◽  
...  
Keyword(s):  
Steady State ◽  
Power Systems ◽  
Power Transformer ◽  
Nonlinear Dynamic Analysis ◽  
Stability And Convergence ◽  
Iron Core ◽  
Voltage Transformer ◽  
Proposed Model ◽  
Transformer Model ◽  
Transient And Steady State

Ferroresonance is one of the most harmful and longest known power quality disturbances in the history of AC power systems. The ability of predicting transient and steady-state ferroresonance simulations mainly depends on the accuracy of the power transformer model. Most existing voltage transformer models apply single-valued nonlinear functions to represent the core nonlinearities. This study, based on our previous work, proposes a newly improved and accurate transformer iron core hysteresis model for ferroresonance simulation by extension of the classical arctangent model. To verify the proposed model’s accuracy and superiority, three different ferroresonant voltage and current waveform simulations were performed using both the proposed model and renowned EMTP Type-96 model under the same system parameters. In addition, simulation results were compared with the corresponding experimental measurements. The results indicate that the proposed model is easily implemented using numerical modeling method with good stability and convergence, and is sufficiently accurate for both transient and steady-state periodic ferroresonance analysis.

Modeling Transient/Steady-State Convection From Isoflux Vertical Plates

2012 ◽  
Author(s):  
Mehran Ahmadi ◽  
Majid Bahrami
Keyword(s):  
Experimental Data ◽  
Steady State ◽  
Analytical Model ◽  
Vertical Plate ◽  
Convection Heat Transfer ◽  
Constant Property ◽  
Nusselt Numbers ◽  
Proposed Model ◽  
Transient And Steady State ◽  
State Average

A new compact analytical model is developed to predict transient heat convection from isoflux vertical plates into a constant property surrounding region. The proposed model is based on a blending of the two asymptotes corresponding to transient diffusion into a half-space and the steady-state convection heat transfer from an isoflux vertical plate. A compact relation for transient and steady-state average Nusselt numbers is proposed. The proposed model is successfully verified with existing experimental data of Goldstein and Eckert. The maximum difference between the proposed compact analytical model and the experimental data is less than 6%.

scholarly journals Correlation of Steady State and Transient Temperature Profiles in Perfused Fixed Kidneys: Implications for Thermal Models

2021 ◽  
Author(s):  
Michael C. Kolios ◽  
Michael D. Sherar ◽  
A. E. Worthington ◽  
J. W. Hunt
Keyword(s):  
Steady State ◽  
Transient Temperature ◽  
Temperature Profiles ◽  
Thermal Models

Correlation of Steady State and Transient Temperature Profiles in Perfused Fixed Kidneys: Implications for Thermal Models

Transient Temperature Profiles in Tissues With Nonuniform Blood Flow Distributions

1982 ◽  
Vol 104 (3) ◽  
pp. 202-208 ◽  
Author(s):  
A. B. Elkowitz ◽  
A. Shitzer ◽  
R. C. Eberhart
Keyword(s):  
Heat Transfer ◽  
Blood Flow ◽  
Steady State ◽  
Flow Distribution ◽  
Tissue Blood Flow ◽  
Transient Temperature ◽  
Temperature Profiles ◽  
Heat Transfer Equation ◽  
Blood Flow Distribution ◽  
Steady State Temperature

Numerical methods and the bio-heat transfer equation are employed to calculate temperature profiles in tissues subjected to nonuniform blood flow distributions, for initial and boundary conditions which simulate experimental physiological situations. Results indicate that one can infer, from sudden changes in temperature distribution, the occurrence of sudden changes in tissue blood flow. However, prediction of blood flow distribution from near equilibrium or steady-state temperature profiles is of poor resolution, and does not appear useful as a practical technique. The methods and results are useful for predictions of temperature profiles in the absence of significant endogenous or exogenous heating; they can be extended to such applications by straightforward methods.

High-speed isotachophoresis. Analytical aspects of the steady-state longitudinal temperature profiles

1979 ◽  
Vol 44 (3) ◽  
pp. 841-853 ◽  
Author(s):  
Zbyněk Ryšlavý ◽  
Petr Boček ◽  
Miroslav Deml ◽  
Jaroslav Janák
Keyword(s):  
Steady State ◽  
Temperature Distribution ◽  
Electric Field ◽  
Field Intensity ◽  
Electric Field Intensity ◽  
Minor Component ◽  
Physical Models ◽  
Temperature Profiles ◽  
Longitudinal Temperature ◽  
Continuous Character

The problem of the longitudinal temperature distribution was solved and the bearing of the temperature profiles on the qualitative characteristics of the zones and on the interpretation of the record of the separation obtained from a universal detector was considered. Two approximative physical models were applied to the solution: in the first model, the temperature dependences of the mobilities are taken into account, the continuous character of the electric field intensity at the boundary being neglected; in the other model, the continuous character of the electric field intensity is allowed for. From a comparison of the two models it follows that in practice, the variations of the mobilities with the temperature are the principal factor affecting the shape of the temperature profiles, the assumption of a discontinuous jump of the electric field intensity at the boundary being a good approximation to the reality. It was deduced theoretically and verified experimentally that the longitudinal profiles can appreciably affect the longitudinal variation of the effective mobilities in the zone, with an infavourable influence upon the qualitative interpretation of the record. Pronounced effects can appear during the analyses of the minor components, where in the corresponding short zone a temperature distribution occurs due to the influence of the temperatures of the neighbouring zones such that the temperature in the zone of interest in fact does not attain a constant value in axial direction. The minor component does not possess the steady-state mobility throughout the zone, which makes the identification of the zone rather difficult.

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