In this paper 3D simulations of four different horizontal axis wind turbine (HAWT) blade shapes with the same radius (0.65m) and airfoil profile (NACA4418) are presented. The first blade shape is optimal twist and tapered (OPT); this blade is designed using blade element momentum (BEM) theory. The second is un-tapered and optimal twist (UOT), this blade has the same twist distribution as the (OPT) but with a constant chord. The third is tapered un-twisted (TUT), this blade has the same chord variations as the OPT blade. The fourth is untapered un-twisted (UUT). The effect of nacelle, shaft and tower existence on the performance of the four designs has been investigated also in the present work.All simulations are performed by using shear stress transport (SST) k-ω turbulence model. The power coefficient of OPT blade reach to 0.317 at TSR = 5. Meanwhile, the maximum power coefficient (Cp=0.3348 at TSR=4) has been recorded in the UOT blade. The TUT and UUT blade recorded a lower power coefficient, this is due to their always operations in stall and turbulence conditions.
Degradation reduces the capability of solar photovoltaic (PV) production over time. Studies on PV module degradation are typically based on time-consuming and labor-intensive accelerated or field experiments. Understanding the modes and methodologies of degradation is critical to certifying PV module lifetimes of 25 years. Both technological and environmental conditions affect the PV module degradation rate. This paper investigates the degradation of 24 mono-crystalline silicon PV modules mounted on the rooftop of Egypt's electronics research institute (ERI) after 25 years of outdoor operation. Degradation rates were determined using the module's performance ratio, temperature losses, and energy yield. Visual inspection, I–V characteristic measurement, and degradation rate have all been calculated as part of the PV evaluation process. The results demonstrate that the modules' maximum power ($${P}_{max}$$ P max ) has decreased in an average manner by 23.3% over time. The degradation rates of short-circuit current ($${I}_{sc}$$ I sc ) and maximum current ($${I}_{m}$$ I m ) are 12.16% and 7.2%, respectively. The open-circuit voltage ($${V}_{oc}$$ V oc ), maximum voltage ($${V}_{m}$$ V m ), and fill factor ($$FF$$ FF ) degradation rates are 2.28%, 12.16%, and 15.3%, respectively. The overall performance ratio obtained for the PV system is 85.9%. After a long time of operation in outdoor conditions, the single diode model's five parameters are used for parameter identification of each module to study the effect of aging on PV module performance.
This study aims to achieve a close spectral match to the AM1.5 solar spectrum from 400 nm to 1100 nm. LEDs are selected to achieve this target due to its wide utilization in markets; a vast range of LED wavelengths is available from UV through visible to IR. The spectral mismatch can increase the measurement uncertainty significantly. Solar simulator lighting subsystem design based on LED as a light source only is presented. Selecting the required LEDs combination to match the AM 1.5 using traditional methods is very difficult. This complex optimization problem has been solved by Genetic Algorithm (GA) to obtain the optimal combination of different LEDs in the range of 400 to 1100 nm. Moreover, spectral match and spectral ratio have been calculated. The results proved that, as the number of LED data entry varying, the solar simulator classification changes.
In this paper, a complete LED-based solar simulator prototype is designed and implemented. The proposed light source of this solar simulator is formed using only six different types of LEDs to simulate the AM 1.5G spectrum. In addition, the flyback converter is designed to provide the required power of the solar simulator. In order to monitor and adjust the temperature at Standard Test Conditions (STC) of 25 °C, a proposed PID controller is applied and implemented using Arduino Mega 2560. The LED-based solar simulator prototype implementation has been achieved. The performance of the solar simulator prototype has been verified and tested.
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