Pumped storage system for wind energy in variable operating conditions

Author(s):  
Andreea Busca-Forcos ◽  
Corneliu Marinescu
2020 ◽  
pp. 43-54
Author(s):  
Helena M. Ramos ◽  
◽  
Mariana Simão

A elevada intermitência das fontes de energia renováveis condiciona a produção de energia elétrica, que continua a depender muito dos combustíveis fósseis. Uma vez que existe complementaridade por parte das fontes de energia renováveis, a sua integração conjunta é, sem dúvida, a melhor solução para reduzir esta dependência. Aliado a este facto, poderá coexistir um sistema de armazenamento por bombagem, capaz de gerar reservas hídricas, que serão aproveitadas quando a procura exceder a oferta energética. Procedeu-se ao desenvolvimento de dois modelos: um sobre custos de turbomáquinas e outro que visa o estudo do potencial de recuperação de energia de uma solução energética híbrida com armazenamento por bombagem combinado com fonte de energia eólica. Foram estudadas diferentes combinações para estas duas fontes de energia renovável, analisando o consumo satisfeito e a energia eólica não consumida, tendo-se concluído que o excedente de energia eólica pode ser aproveitado para bombagem. The high intermittence of renewable energy sources determines the production of electricity, which remains highly dependent on fossil fuels. Since there is complementarity between renewable energy sources, their joint integration is a potential solution to reduce this dependency. Consequentially, a pumping storage system capable of generating water reserves can coexist, which will be used when demand exceeds the energy supply. Two models were developed: one based on turbomachinery costs and the other based on the potential of energy recovery of a hybrid energy solution with pump storage combined with wind energy. Different combinations were studied for these two sources, analysing the satisfied consumption and the wind energy that is not consumed, in which it was concluded that the surplus of wind energy can be used by pumped storage.


2019 ◽  
Vol 8 (4) ◽  
pp. 1772-1779

In the research work, impactness of Renewable Energy source like Wind Energy is reinforced to enhance the dynamic performance of Thermal and Hydro power plant under various operating conditions in which steam act as a major contributor for generation of electricity and rest of the generation through water. This technique is helpful in agricultural as well as islet spaces. The uneven generation of power will cause fluctuation in load followed by large disturbance in frequency of power system. To overcome this nature of fluctuations, wind energy will offer and consume instantly the true and apparent powers. The execution and it’s testing are exhausted in a convenient MATLAB/Simulink condition with the application of step load and a continuing load perturbation of 1% within the system and whose results exposed that involvement of wind energy storage unit in the hybrid Thermal Hydro power system enhance transient performance of each thermal & hydro sides.


2014 ◽  
Vol 42 (1) ◽  
pp. 2-15
Author(s):  
Johannes Gültlinger ◽  
Frank Gauterin ◽  
Christian Brandau ◽  
Jan Schlittenhard ◽  
Burkhard Wies

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.


Author(s):  
Tonny Tabassum Mainul Hasan ◽  
Latifa Begum

This study reports on the unsteady two-dimensional numerical investigations of melting of a paraffin wax (phase change material, PCM) which melts over a temperature range of 8.7oC. The PCM is placed inside a circular concentric horizontal-finned annulus for the storage of thermal energy. The inner tube is fitted with three radially diverging longitudinal fins strategically placed near the bottom part of the annulus to accelerate the melting process there. The developed CFD code used in Tabassum et al., 2018 is extended to incorporate the presence of fins. The numerical results show that the average Nusselt number over the inner tube surface, the total melt fraction, the total stored energy all increased at every time instant in the finned annulus compared to the annulus without fins. This is due to the fact that in the finned annulus, the fins at the lower part of the annulus promotes buoyancy-driven convection as opposed to the slow conduction melting that prevails at the bottom part of the plain annulus. Fins with two different heights have been considered. It is found that by extending the height of the fin to 50% of the annular gap about 33.05% more energy could be stored compared to the bare annulus at the melting time of 82.37 min for the identical operating conditions. The effects of fins with different heights on the temperature and streamfunction distributions are found to be different. The present study can provide some useful guidelines for achieving a better thermal energy storage system.


1997 ◽  
Vol 35 (2-3) ◽  
pp. 85-91
Author(s):  
D. A. Barton ◽  
J. D. Woodruff ◽  
T. M. Bousquet ◽  
A. M. Parrish

If promulgated as proposed, effluent guidelines for the U.S. pulp and paper industry will impose average monthly and maximum daily numerical limits of discharged AOX (adsorbable organic halogen). At this time, it is unclear whether the maximum-day variability factor used to establish the proposed effluent guidelines will provide sufficient margin for mills to achieve compliance during periods of normal but variable operating conditions within the pulping and bleaching processes. Consequently, additional information is needed to relate transient AOX loadings with final AOX discharges. This paper presents a simplistic dynamic model of AOX decay during treatment. The model consists of hydraulic characterization of an activated sludge process and a first-order decay coefficient for AOX removal. Data for model development were acquired by frequent collection of influent and effluent samples at a bleach kraft mill during a bleach plant shutdown and startup sequence.


2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Inês Melo ◽  
João Paulo Neto Torres ◽  
Carlos Alberto Ferreira Fernandes ◽  
Ricardo A. Marques Lameirinhas

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