Advanced Energy Technologies
Mohammad Rahimzadeh; Hamid Samadi; Nikta Shams Mohammadi
Abstract
Energy harvesting from ambient vibrations using piezoelectric cantilevers is one of the most popular mechanisms for producing electrical energy. Recently, efforts have been made to improve the performance of energy harvesters. The output voltage dramatically depends on the geometrical and physical parameters ...
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Energy harvesting from ambient vibrations using piezoelectric cantilevers is one of the most popular mechanisms for producing electrical energy. Recently, efforts have been made to improve the performance of energy harvesters. The output voltage dramatically depends on the geometrical and physical parameters of these devices. In addition, improved performance is often achieved by operating at or near the resonance point. So, this paper aims to reduce the natural frequency to match the environmental excitation frequency and increase the harvested energy. For this purpose, different geometrical and physical parameters are studied to determine the impact of each parameter. These parameters include the length, thickness, density, and Young’s modulus of each layer. The beam is considered a unimorph cantilever with rectangular configuration and the study is performed using COMSOL Multiphysics software. The results are compared with those obtained by an analytical approach. The results show that changing the parameters made the natural frequency of the system vary in the range of 20 Hz to 200 Hz and increased the output voltage up to 20 V.
Advanced Energy Technologies
Mohammad Rasooli Mavini; Hassan Ali Ozgoli; Sadegh Safari
Abstract
In this study, various configurations design of a Heat Recovery Steam Generator (HRSG) are examined to enhance energy efficiency of a Combined Cycle Power Plant (CCPP). A novel approach is used to investigate ten applicable configurations of a dual pressure Heat Recovery Steam Generator HRSG thoroughly ...
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In this study, various configurations design of a Heat Recovery Steam Generator (HRSG) are examined to enhance energy efficiency of a Combined Cycle Power Plant (CCPP). A novel approach is used to investigate ten applicable configurations of a dual pressure Heat Recovery Steam Generator HRSG thoroughly to explore the best practice models from the energy-conserving considerations. Further, a fuel consumption assessment has been conducted to identify the best performance of the cycle and investigate the minimum pollutants released of each Heat Recovery Steam Generator (HRSG) configuration. The results have revealed that four scenarios among ten, have expressed a considerably better performance regarding; fuel consumption, steam production, energy efficiency, and finally yet importantly environmental considerations. Further, it has been found that in comparison to the conventional configuration, not only the selected scenarios have proved almost four times improvement in the low-pressure steam generation, but also 30% fuel consumption saving in supplementary firing has been achieved which has both economic and environmental benefits. Moreover the carbon dioxide saving potential for the best scenario is 51.37 kgCO2 MWh-1 consequently the environmental benefit of it is calculated about 133,418 $ MWh-1.