scholarly journals The Impact of Air Mass on the Performance of a Monocrystalline Silicon Solar Module in Kakamega

Author(s):  
Ligavo Margdaline Musanga ◽  
Mageto Maxwell ◽  
Wafula Henry Barasa ◽  
Emmanuel Yeri Kombe

This paper investigates the outdoor performance of a 20 W monocrystalline silicon solar module in relation to air mass (AM) in Kakamega. Direct measurement of air mass and module output parameters from experimental setup was done in Kakamega at a location 0.28270 N and 34.7519 E. Experimental results showed a decrease in ISC and VOC with increasing AM. The maximum output power produced by the module reduced with an increase in AM. Maximum power was therefore seen to be produced at noon in this region. VOC increased from 19.47 to 20.04 then decreased to 19.49 V while ISC increased from 0.36 to 1.19 then decreased to 0.48A.  It was observed that both the FF and   of a monocrystalline solar module increase with increase in air mass. The module performed better during the afternoon than morning and evening hours with the peak performance observed close to AM 1.

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Hong Yang ◽  
He Wang ◽  
Dingyue Cao ◽  
Dangmin Sun ◽  
Xiaobao Ju

During the course of solar module encapsulation, the output power of crystalline silicon solar module is less than the sum of the maximum output power of the constituents because of power loss. So it is very important to investigate the power loss caused by encapsulation materials and module production process. In this paper, the power loss of crystalline silicon solar module is investigated by experiments systematically for the first time. It is found that the power loss is mainly caused by the resistance of ribbon and mismatch of solar cells; the total power loss is as high as 3.93% for solar module composed of 72 cells (125 mm × 125 mm) connected in series. Analyzing and reducing the power losses are beneficial to optimizing encapsulation process for the solar module. The results presented in this study give out a direction to decreasing power loss and optimizing encapsulation process of crystalline silicon solar module.


2011 ◽  
Vol 1325 ◽  
Author(s):  
Kazuaki Yazawa ◽  
Ali Shakouri

ABSTRACTA recently developed generic model of a thermoelectric power generation system suggests a promising future for cost effective and scalable power generation. The model is based on co-optimizing the thermoelectric module together with the heat sink. Using this model, efficiency at maximum output power is calculated. It is shown that this approaches the Curzon-Ahlborn limit at very large Z values which is consistent with thermodynamic systems with irreversible heat engines. However, this happens only when the thermal resistances of the thermoelectric device with hot and cold heat sinks exactly match. For asymmetrical thermal resistances, the efficiency at maximum output power is different. This is consistent with the very recent results for the thermodynamic engines. Finally, we study the impact of lowering the thermal conductivity of the thermoelectric material or increasing its power factor and how these affect the performance of the thermoelectric power generation system.


2020 ◽  
Vol 8 (1) ◽  
pp. 45-51
Author(s):  
R.E. Klimov ◽  
◽  
V.Yu. Lekarev ◽  
D.G. Tsarichenko ◽  
А.М. Dymov ◽  
...  

At present, minipercutaneous nephrolithotripsy is a highly effective and safe method for fragmentation of stones with sizes up to 3 cm. The use for lithotripsy of a holmium: yttrium aluminum garnet laser with wavelength 2.1 μm (Ho:YAG) is a common practice today. Of late, however, more attention is paid to a new superpulse thulium fiber laser with wavelength 1.94 μm and maximum output power 40 W. The use of a thulium laser with pulse energy 0.025–6 J and a high repetition rate (to 1600 Hz) permits to obtain (compared with a holmium laser) better results of stone dusting. Objective. Selection of the optimal modes of stone fragmentation in minipercutaneous nephrolithotripsy with the use of a superpulse thulium fiber laser with wavelength 1.94 μm and maximum output power 40 W in patients with nephrolithiasis. Patients and methods. The study included patients (n = 171), who underwent minipercutaneous nephrolithotripsy using a superpulse thulium fiber laser during the period from February 2018 to July 2019. The following parameters of laser radiation were used: pulse energy 0.1-6 J, power 6-40 W, pulse rate 30-300 Hz. The impact of modes on endoscopic visualization and retropulsion was assessed intraoperatively. Results. Statistical analysis of the specificities of the most often used modes was conducted: No 1 – «0.15 J, 200 Hz, 30 W», No 2 – «0.5 J, 30 Hz, 15 W», No 3 – «0.8 J, 31.25 Hz, 25 W», No 4 – «0.8 J, 37.5 Hz, 30 W», No 5 – «1.5 J, 15 Hz, 30 W», No 6 – «1.5 J, 26.6 Hz, 40 W», No 7 – «2 J, 15 Hz, 30 W», No 8 – «2 J, 20 Hz, 40 W», No 9 – «4 J, 10 Hz, 40 W»; their effects on retropulsion and on endoscopic visualization were studies. The stone free rate was assessed on the first post-operative day according to the findings of low-dose CT. Conclusion. Study of the modes of thulium fiber lithotripsy, assessment of retropulsion and endoscopic visualization depending on the choice of emitted radiation parameters of a thulium fiber laser make it possible to improve the outcomes of operative treatment in patients with nephrolithiasis. Key words: minipercutaneous, nephrolithotripsy, nephrolithiasis, MPNL, thulium fiber lithotripsy, retropulsion, visibility, superpulse thulium fiber laser, wavelength 1.94 μm, stone free rate


Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 508
Author(s):  
Kui You ◽  
Zihan Zhou ◽  
Chao Gao ◽  
Qiao Yang

Biochar is a kind of carbon-rich material formed by pyrolysis of biomass at high temperature in the absence or limitation of oxygen. It has abundant pore structure and a large surface area, which could be considered the beneficial characteristics for electrodes of microbial electrochemical systems. In this study, reed was used as the raw material of biochar and six biochar-based electrode materials were obtained by three methods, including one-step biochar cathodes (BC 800 and BC 700), biochar/polyethylene composite cathodes (BP 5:5 and BP 6:4), and biochar/polyaniline/hot-melt adhesive composite cathode (BPP 5:1:4 and BPP 4:1:5). The basic physical properties and electrochemical properties of the self-made biochar electrode materials were characterized. Selected biochar-based electrode materials were used as the cathode of sediment microbial electrochemical reactors. The reactor with pure biochar electrode (BC 800) achieves a maximum output power density of 9.15 ± 0.02 mW/m2, which increases the output power by nearly 80% compared with carbon felt. When using a biochar/polyaniline/hot-melt adhesive (BPP 5:1:4) composite cathode, the output power was increased by 2.33 times. Under the premise of ensuring the molding of the material, the higher the content of biochar, the better the electrochemical performance of the electrodes. The treatment of reed powder before pyrolysis is an important factor for the molding of biochar. The one-step molding biochar cathode had satisfactory performance in sediment microbial electrochemical systems. By exploring the biochar-based electrode, waste biomass could be reused, which is beneficial for the environment.


Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 391
Author(s):  
Nan Wu ◽  
Yuncheng He ◽  
Jiyang Fu ◽  
Peng Liao

In this paper a novel hybrid piezoelectric and electromagnetic energy harvester for civil engineering low-frequency sloshing environment is reported. The architecture, fabrication and characterization of the harvester are discussed. The hybrid energy harvester is composed of a permanent magnet, copper coil, and PVDF(polyvinylidene difluoride) piezoelectric film, and the upper U-tube device containing a cylindrical fluid barrier is connected to the foundation support plate by a hinge and spring. The two primary means of energy collection were through the vortex street, which alternately impacted the PVDF piezoelectric film through fluid shedding, and the electromotive force (EMF) induced by changes in the magnetic field position in the conducting coil. Experimentally, the maximum output power of the piezoelectric transformer of the hybrid energy harvester was 2.47 μW (circuit load 270 kΩ; liquid level height 80 mm); and the maximum output power of the electromagnetic generator was 2.72 μW (circuit load 470 kΩ; liquid level height 60 mm). The low-frequency sloshing energy collected by this energy harvester can drive microsensors for civil engineering monitoring.


Laser Physics ◽  
2021 ◽  
Vol 32 (2) ◽  
pp. 025801
Author(s):  
Xiangrui Liu ◽  
Zhuang Li ◽  
Chengkun Shi ◽  
Bo Xiao ◽  
Run Fang ◽  
...  

Abstract We demonstrated 22 W LD-pumped high-power continuous-wave (CW) deep red laser operations at 718.5 and 720.8 nm based on an a-cut Pr3+:YLF crystal. The output power of both polarized directions reached the watt-level without output power saturation. A single wavelength laser operated at 720.8 nm in the π-polarized direction was achieved, with a high output power of 4.5 W and high slope efficiency of approximately 41.5%. To the best of our knowledge, under LD-pumped conditions, the laser output power and slope efficiency are the highest at 721 nm. By using a compact optical glass plate as an intracavity etalon, we suppressed the π-polarized 720.8 nm laser emission. And σ-polarized single-wavelength laser emission at 718.5 nm was achieved, with a maximum output power of 1.45 W and a slope efficiency of approximately 17.8%. This is the first time that we have achieved the σ-polarized laser emission at 718.5 nm generated by Pr3+:YLF lasers.


Author(s):  
James F. Walton ◽  
Andrew Hunsberger ◽  
Hooshang Heshmat

In this paper the authors will present the design and preliminary test results for a distributed electric generating system that uses renewable energy source for economical load-following and peak-shaving capability in an oil-free, high-speed micro-turboalternator system using compliant foil bearings and a permanent magnet alternator. Test results achieved with the prototype system operating to full speed and under power generating mode will be presented. A comparison between predicted and measured electrical output will also be presented up to a power generating level of 25 kWe at approximately 55,000 rpm. The excellent correlation between design and test provides the basis for scale up to larger power levels. Based upon the turboalternator test results a thermodynamic cycle analysis of a system using low grade waste heat water at approximately 100 C will be reviewed. The tradeoff study results for a series of environmentally friendly refrigerant working fluids will also be presented including sensitivity to vaporization and condensing temperatures. Based on the cycle and pinch point analyses predicted maximum output power was determined. Finally a preliminary turbine design for the selected R134a working fluid was completed. The results of this study show that a net output power level of greater than 40 kW is possible for approximately 240 l/m flow of water at 100C is possible.


Author(s):  
S. D. Moss ◽  
L. A. Vandewater ◽  
S. C. Galea

This work reports on the modelling and experimental validation of a bi-axial vibration energy harvesting approach that uses a permanent-magnet/ball-bearing arrangement and a wire-coil transducer. The harvester’s behaviour is modelled using a forced Duffing oscillator, and the primary first order steady state resonant solutions are found using the homotopy analysis method (or HAM). Solutions found are shown to compare well with measured bearing displacements and harvested output power, and are used to predict the wideband frequency response of this type of vibration energy harvester. A prototype harvesting arrangement produced a maximum output power of 12.9 mW from a 12 Hz, 500 milli-g (or 4.9 m/s2) rms excitation.


2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Zhipeng Qin ◽  
Guoqiang Xie ◽  
Jian Zhang ◽  
Jingui Ma ◽  
Peng Yuan ◽  
...  

We report on a continuous-wave (CW) and passively Q-switched Er:Y2O3 ceramic laser in mid-infrared spectral region. In the CW regime, a maximum output power of 2.07 W is achieved at 2717.3 nm with a slope efficiency of 13.5%. Stable passive Q-switching of the Er:Y2O3 ceramic laser is demonstrated based on semiconductor saturable absorber mirror. Under an absorbed pump power of 12.4 W, a maximum average output power of 223 mW is generated with a pulse energy of 1.7 μJ and a pulse width of 350 ns at 2709.3 nm.


Sign in / Sign up

Export Citation Format

Share Document