Amir Abtahi

Annual performance comparison between tracking and fixed photovoltaic arrays

In this paper a performance comparison is conducted between a new grid-tied PV tracking system and a fixed mounting grid-tied PV system with identical solar panels as well as the same rated powers in one-year period. These systems were installed at Florida Atlantic University (FAU) in Boca Raton, Florida, started operating in August 2014. First, an overview of the entire system is presented followed by the description of system architecture design. A detailed statistical comparison is done for four months in four seasons. At the end, the annual energy output of tracker and non-tracker units is extracted and analyzed. Two important performance factors such as annual power production of each array and the amount of system CO2 emission reduction are calculated. It is concluded from final results that the single axis tracker, which continuously tracks the sun from east to west during daytime, works moderately in south Florida region and therefore it requires more thorough researches to improve the system efficiency.

Design and implementation of a hierarchical control strategy for proton exchange membrane fuel cells

The modeling and control strategies for proton exchange membrane (PEM) fuel cells are presented. Two different pulsing methodologies were designed and implemented in Fuel Cell Laboratory at Florida Atlantic University in order to increase the efficiency and performance of PEM fuel cells. The schedule experiments for each method comprised of varying the pulse amplitude, the frequency and the duty cycles. The amplitude variations were controlled by a pressure regulator on the pulsed air source; frequency and duty cycle changes were implemented using computer software in conjunction with A/D, D/A, timer and electronic circuits. The experimental results are promising. Further experimental work to improve the efficiency of PEM fuel cells based on an intelligent hybrid control strategy is under investigation.

Optimal operation of a multi-source microgrid to achieve cost and emission targets

This paper presents a new approach for the optimization of photovoltaic-wind hybrid systems with battery storage to meet the load requirements. In this study, a 24-hour ahead energy management for a microgrid is utilized. The objectives aim at raising efficiency of energy utilization, minimizing operational cost and reducing environmental effects of energy usage. Also a demand response (DR) program is considered as one of the cost-effective energy alternatives. Based on the prediction of available energy from the PV and wind generators, battery storage availability, load prediction, micro gas turbine (μGT) and main grid emission characteristics, a central energy management system calculates a day-ahead plan of power references for the gas turbine, power purchased from the grid, power sold to the grid, status of the battery and controllable loads. A multi-objective optimization is implemented in order to minimize the energy cost and greenhouse gas emissions.

Pulse-Width Modulation of Hydrogen Delivery for PEM Fuel Cells

Pulse-width modulation of hydrogen delivery is proposed to accomplish better performance of PEM fuel cells. By evaluating power consumption patterns and time delays associated with hydrogen and air consumption, optimal functional feedback controllers are developed. By matching the ON and OFF times for the hydrogen and oxygen supply valves, in conjunction with a system fuzzy controller (1), the power output is matched to specific load requirements. The fluid transient behavior is also monitored, to develop functional relationships between the power curve, and the fluid conditions, in order to optimize the system performance. These functions are then used to update and improve the performance of the controller.Copyright

Optimal energy scheduling of a stand-alone multi-sourced microgrid considering environmental aspects

A standalone microgrid with renewable and regular power resources along with storage system play an important role in remote areas in order to solve power supply problems. In this research, an optimal energy management of a standalone microgrid under different operational modes is studied. The objective of the optimization model is to improve energy utilization efficiency; reduce fuel cost and gas emissions by scheduling productions of energy resources in each hour on the next day. In another word, the problem is modeled as a constrained single-objective programming to minimize cost of power and emission generations. The system is tested under two different operational policies where microgrid power generation sources work with and without battery storage system. Then the final results are compared and investigated. The results show a considerable reduction in system total cost and generated emission in comparison with previously proposed methods.

Performance evaluation of hybrid thin-film versus conventional photovoltaic arrays

This paper evaluates the performance of two solar arrays located in Palm City, Florida. The main goal of this study is to compare the annual performance of a solar array with hybrid Smart-Silicon Thin-Film panels and a conventional solar array. The system was designed and installed for two photovoltaic arrays with the same number of panels that started operation in December 2014. First, an overview of the entire system is presented followed by the description of system architecture design. A statistical comparison is done for system daily and monthly power production. Also, the annual energy output of hybrid and conventional units is extracted and analyzed. At the end, annual power production of each array and the amount of system CO2 emission reduction are calculated. It is concluded from final results that the hybrid solar system has better efficiency in wintertime and performs marginally better than the one with regular solar panels. In order to improve the system efficiency, more precise researches are required in terms of positioning and temperature sensitivity.

An Overview of Current Research Activities on PEM Fuel Cell Technology at Florida Atlantic University

The Fuel Cell Laboratory at Florida Atlantic University (FAU) originally founded to support a research funded by the US Department of Energy under the leading author’s supervision during 1996-1997 period [1]. In sequel, the laboratory has been upgraded with several industrial funding supports, including Teledyne Inc., Enerfuel Inc, in addition to the National Science Foundation (NSF) and FAU internal research funds. With the continuing support of local FC industries, the laboratory is considered a focal point for the research and educational activities pertaining to proven fuel cell testing technology. In this paper, an overview of several research and instructional activities of FAU Fuel Cell Laboratory are briefly presented.