scholarly journals DIMENSIONAMENTO DE SISTEMAS FOTOVOLTAICOS CONECTADOS À REDE APLICADOS A EDIFICAÇÕES RESIDENCIAIS E COMERCIAIS: URBANAS E RURAIS

2021 ◽  
Vol 36 (1) ◽  
pp. 41-57
Author(s):  
Alcides Arruda Junior ◽  
Ozlean de Lima Dantas ◽  
Roberto Apolonio

DIMENSIONAMENTO DE SISTEMAS FOTOVOLTAICOS CONECTADOS À REDE APLICADOS A EDIFICAÇÕES RESIDENCIAIS E COMERCIAIS: URBANAS E RURAIS   ALCIDES ARRUDA JUNIOR1, OZLEAN DE LIMA DANTAS2, ROBERTO APOLONIO2   1Universidade Federal de Mato Grosso - UFMT, Faculdade de Agronomia e Zootecnia – FAAZ, Programa de Pós-Graduação em Agricultura Tropical – PPGAT, Av. Fernando Corrêa da Costa, n°2367, Bairro: Boa Esperança - Cuiabá - MT, Brasil, CEP: 78060900, E-mail: [email protected]. 2Universidade Federal de Mato Grosso – UFMT, Faculdade de Engenharia e Tecnologia – FAET, Departamento de Engenharia Elétrica - DENE, Endereço: Av. Fernando Corrêa da Costa, nº 2367. Bairro Boa Esperança - Cuiabá – Mato Grosso, Brasil, CEP: 78060-900, E-mail: [email protected], [email protected].   RESUMO: O objetivo deste trabalho é apresentar uma nova proposta de metodologia para o dimensionamento de sistema Fotovoltaicos Conectados à Rede (SFVCR), cujo passo a passo foi definido por meio de uma análise sistemática de literaturas nacionais e internacionais, sobre a temática de dimensionamento de SFVCR. Como síntese desta análise extraiu-se as principais informações, critérios, considerações técnicas e equacionamentos, que não estavam disponíveis de forma sintética, nem organizados de forma sequencial, lógica e didática. Acredita-se que a principais contribuições deste trabalho são: uma nova metodologia detalhada, passo a passo com critérios para ajustamento ótimo entre o gerador fotovoltaico (GFV) e o inversor (IFV), visando uma operação segura, dentro dos padrões nominais dos equipamentos, sem comprometer suas vidas úteis; e ainda a proposta de uma nova equação para o cálculo da potência máxima de saída do sistema aperfeiçoada com os mais diversos fatores de perdas concatenados em uma única expressão matemática. Conclui-se que a metodologia apresentada neste artigo poderá contribuir para sanar muitas das dúvidas existentes quanto ao tema do dimensionamento de SFVCR, especialmente no que se refere ao ajustamento entre o GFV e o IFV, e auxiliar estudos de viabilidade técnica para  previsão e pré-dimensionamento de SFVCR para aplicação em edificações residenciais e comerciais, sejam elas urbanas ou rurais.   Palavras-Chave: energia, sustentabilidade, tecnologias renováveis.   SIZING OF GRID CONNECTED PHOTOVOLTAIC SYSTEMS APPLIED TO RESIDENTIAL AND COMMERCIAL BUILDINGS: URBAN AND RURAL.   ABSTRACT: this work aims to present a new methodology proposal for the dimensioning of grid connected photovoltaic systems (GCPVS), whose step by step was defined by means of a systematic analysis of national and international literature, on the theme of dimensioning of GCPVS. As a synthesis of this analysis, the main information, criteria, technical considerations and equations were extracted, which were not available in a synthetic form, nor were they organized in a sequential, logical and didactic way. The main contributions of this work are: a new detailed methodology, step by step with criteria for optimal adjustment between the photovoltaic generators (PVG) and the inverter (PVI), aiming at a safe operation, within the nominal standards of the equipment, without compromising their useful lives; and the proposal of a new equation for calculating the maximum output power of the system perfected with the most diverse loss factors concatenated in a single mathematical expression. It is concluded that the methodology presented in this article can help resolve many of the existing doubts regarding the issue of SFVCR dimensioning, especially regarding the adjustment between the GFV and the IFV, and auxiliary technical feasibility studies for forecasting and pre- SFVCR dimensioning for application in residential and commercial buildings, whether urban or rural.   Keywords: energy, sustainability, renewable technologies.

Author(s):  
X. Zhang ◽  
Y. Pan ◽  
T.T. Meek

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.


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.


Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7334
Author(s):  
Seongwoog Oh ◽  
Jungsuek Oh

This paper proposes a novel design for a chip-on-probe with the aim of overcoming the heat dissipation effect during brain stimulations using modulated microwave signals. The temperature of the stimulus chip during normal operation is generally 40 °C–60 °C, which is sufficient to cause unintended temperature effects during stimulation. This effect is particularly fatal in brain stimulation applications that require repeated stimulation. This paper proposes, for the first time, a topology that vertically separates the stimulus chip generating the stimulus signal and the probe delivering the signal into the brain to suppress the heat transfer while simultaneously minimizing the radio frequency (RF) transmission loss. As the proposed chip-on-probe should be attached to the head of a small animal, an auxiliary board with a heat sink was carefully designed considering the weight that does not affect the behavior experiment. When the transition structures are properly designed, a heat sink can be mounted to maximize the cooling effect, reducing the temperature by more than 13 °C in a simulation when the heat generated by the chip is transferred to the brain, while the transition from the chip to the probe experiences a loss of 1.2 dB. Finally, the effectiveness of the proposed design is demonstrated by fabricating a chip with the 0.28 μm silicon-on-insulator (SOI) complementary metal–oxide–semiconductor (CMOS) process and a probe with a RT6010 printed-circuit board (PCB), showing a temperature reduction of 49.8 °C with a maximum output power of 11 dBm. In the proposed chip-on-probe device, the temperature formed in the area in contact with the brain is measured at 31.1 °C.


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.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3460
Author(s):  
Jingcheng Shang ◽  
Yizhou Liu ◽  
Shengzhi Zhao ◽  
Yuefeng Zhao ◽  
Yuzhi Song ◽  
...  

We experimentally investigate the formation of various pulses from a thulium–holmium (Tm–Ho)-codoped nonlinear polarization rotation (NPR) mode-locking fiber oscillator. The ultrafast fiber oscillator can simultaneously operate in the noise-like and soliton mode-locking regimes with two different emission wavelengths located around 1947 and 2010 nm, which are believed to be induced from the laser transition of Tm3+ and Ho3+ ions respectively. When the noise-like pulse (NLP) and soliton pulse (SP) co-exist inside the laser oscillator, a maximum output power of 295 mW is achieved with a pulse repetition rate of 19.85-MHz, corresponding to a total single pulse energy of 14.86 nJ. By adjusting the wave plates, the fiber oscillator could also deliver the dual-NLPs or dual-SPs at dual wavelengths, or single NLP and single SP at one wavelength. The highest 61-order harmonic soliton pulse and 33.4-nJ-NLP are also realized respectively with proper design of the fiber cavity.


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.


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