Browsing by Author "Chen, Chang-An"

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Novel plant development for a high performance 3 kW integrated wind and solar system
(2016-07)
Chai, Hsing-Sheng
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Chen, Chang-An
;
Chen, Chiun-Hsun
;
機械工程學系
;
Department of Mechanical Engineering
This research describes a novel system of four Savonius wind rotors, aligned in parallel. A solar panel system, generating power by solar energy, was positioned in front of the parallel system to guide the airflow impinging on the rotors. This array was installed in rural areas to generate electric power. The effect of the solar panel deflector arrangements, used to guide the air stream, was investigated. This type of plant development has not previously been examined. We employed a computational fluid dynamics software, Fluent, to analyze the flow fields and system performance prior to experimentation, then compared these simulations to our experimental data. The parameters studied include wind velocity, wind direction (with/without solar panel deflector), and the rotational speed of the rotors to identify the relationship between the tip-speed ratio (TSR) and power coefficient (Cp). For the numerical simulation results at TSR 0.8, the maximum Cp value of the parallel system without a solar panel deflector was 0.289, whereas at the optimal spacing between the parallel systems with a deflector (50 cm), the Cp was 0.389. This represents a difference factor of 1.35 between the two Cp values. The velocity vector distribution showed that the deflector could guide the airflow to impinge on the rotors from below, gaining extra wind power. The experimental results show that the wind velocity and rotational speed of the wind rotors exhibit large fluctuations in open fields. To combat this, experiments were repeated in both day and night conditions, in different seasons, to gather a range of Cp and TSR values. The average measured wind speed was 6.9961.52m/s. Four Savonius wind rotors in a parallel system can generate 8.25 kW h of energy per day, with an optimal power generation efficiency of 20.7%. Our 3-kW hybrid wind and solar system, which used optimal simulation conditions to determine its experimental design, can generate 14.55 kW h of power per day, with a corresponding optimal power generation efficiency of 21.7%. Our measured Cp curve shows that a deflector can improve the system performance by up to 10.1%. Published by AIP Publishing.
Novel plant development of a parallel matrix system of Savonius wind rotors with wind deflector
(2015-01-01)
Chen, Chang-An
;
Huang, Tien-Yang
;
Chen, Chiun-Hsun
;
機械工程學系
;
Department of Mechanical Engineering
This work describes a novel system of four Savonius wind rotors in a parallel matrix, installed in rural areas to generate electric power. The effect of wind deflector arrangements, used to concentrate the air stream, is investigated. This type of plant development has not previously been examined. We employ a computational fluid dynamics software, Fluent, to analyze the flow fields and system performance in advance, then compare these simulations to experimental data. The parameters studied include wind velocity, wind direction (with/without deflector) and the rotational speed of the rotors, with the aim of identifying the relationship between the tip-speed ratio (TSR) and power coefficient (C-p). In simulation results, at a TSR of 0.6 the system with a wind deflector performs 1.16 times higher power coefficient than the system without a deflector. Generally, the addition of a wind deflector enhances the performance by 1.09 times, especially within the lower TSR regime (0.2-0.8). The experimental results show that the system with a wind deflector performs 1.23 times higher than the one without deflector, with this maximal difference occurring at a TSR of 0.7. However, when we plot experimental Cp against TSR, we find that the wind deflector enhances the performance by 1.15 times in the higher TSR regime (0.6-1.0). The large fluctuations that occur in measurements are attributable to open field tests where the parameters cannot be controlled as precisely as those in simulations. (C) 2015 AIP Publishing LLC.