Demonstration of Efficient Water Recovery for Fuel Cell Power Systems

2009 ◽  
Author(s):  
Michael G. Izenson ◽  
Jay C. Rozzi
Keyword(s):  
Fuel Cell ◽  
Power Systems ◽  
Power System ◽  
High Water ◽  
Water Recovery ◽  
Recovery Efficiency ◽  
Input Stream ◽  
Higher Power ◽  
Exhaust Stream ◽  
Very High

Water recovery and recycling are key technologies for fuel cell power systems. This paper describes technology to recover and recycle water using a compact, efficient condenser to separate water from a fuel cell exhaust stream. The condenser uses an innovative, micromachined condensing surface to achieve very high condensation mass flux and enable very high water recovery efficiency from a compact system. The condenser is sized for a 5 kWe, solid oxide fuel cell (SOFC) power system, but can easily be scaled up for higher power systems. We demonstrated operation of the condenser using an input stream that simulated the exhaust from an SOFC power system. Our device condensed and recovered 97–99% of the water in the input stream while consuming very little power (about 50 W).

Design and Performance Analysis of a Solid Oxide Fuel Cell/Gas Turbine (SOFC/GT) Hybrid System Used in Combined Cooling Heating and Power System

2011 ◽  
Author(s):  
Hsiao-Wei D. Chiang ◽  
Chih-Neng Hsu ◽  
Wu-Bin Huang ◽  
Chen-Yin Lin ◽  
Chien-Hsiung Lee ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Power System ◽  
Waste Heat ◽  
Double Effect ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Exhaust Temperature ◽  
Hybrid Power ◽  
Combined Cooling ◽  
Very High

With high efficiency and very low emissions, fuel cells have been one of the choices of research in current energy development. The Solid Oxide Fuel Cell (SOFC) is a high temperature type fuel cell. It has the characteristic of very high operating temperature 1,027°C (1,300K). The SOFC has the main advantage of very high performance efficiency (over 50%), but also has very high exhaust temperature. Current studies point out that the combination of SOFC and Gas Turbine (GT) can produce efficiency more than 60%. The exhaust temperature of this hybrid power system can be as high as 227–327°C (500–600K). With this waste heat utilized, we can further improve the overall efficiency of the system. A simulation program of SOFC/GT system and the introduction of the concept of Combined Cooling, Heating, and Power System (CCHP) have been used in this study. The waste heat of SOFC/GT hybrid power generation system was used as the heat source to drive an Absorption Refrigeration System (ARS) for cooling. This waste heat enables the SOFC/GT to generate electricity in the system while providing additional cooling and heating capacity. Therefore, we have a combined CCHP system developed using three major modules which are SOFC, GT, and ARS modules. The SOFC module was verified by our test data. The GT and SOFC/GT modules were compared to a commercial code and literature data. Both the single- and double-effect ARS modules were verified with available literature results. Finally, the CCHP analysis simulation system, which combines SOFC, GT, and ARS, has been completed. With this CCHP configuration system, the fuel usability of the system by our definition could be above 100%, especially for the double effect ARS. This analysis system has demonstrated to be a useful tool for future CCHP designs with SOFC/GT systems.

Status of Pressurized SOFC/Gas Turbine Power System Development at Siemens Westinghouse

2002 ◽  
Author(s):  
Stephen E. Veyo ◽  
Shailesh D. Vora ◽  
Kavin P. Litzinger ◽  
Wayne L. Lundberg
Keyword(s):  
Fuel Cell ◽  
Power Systems ◽  
Power System ◽  
Gas Turbine ◽  
High Efficiency ◽  
System Development ◽  
Hot Water ◽  
Positive System ◽  
The Status ◽  
And Performance

Pressurized solid oxide fuel cell (PSOFC)/micro gas turbine generator (MTG) hybrid power systems have the potential to generate electric power at high efficiency [circa 60% (net AC/LHV)] at multi-hundred kWe and multi-MWe capacities. Thus, good fuel economy and low CO2 emissions are positive system attributes, as are low NOx and SOx emissions due to the propensity of the SOFC for low NOx generation, the need for no firing of the gas turbine combustor during normal hybrid system power operations, and the use of desulfurized fuel. Exhaust temperatures are sufficiently high to enable the recovery of heat for steam/hot-water production, and system energy efficiencies of at least 80% are feasible. Work is ongoing at Siemens Westinghouse on three PSOFC/MTG power systems. Two, with 220 kWe and 300 kWe capacities, are proof-of-concept demonstration units. The 220 kWe PSOFC/MTG power system is in test at the National Fuel Cell Research Center, University of California-Irvine, and the 300 kWe system, which is currently being designed, will be demonstrated in two tests to be performed in Europe. The status of work on the 220 kWe and 300 kWe power systems is reviewed. The third system is to have capacity of at least 500 kWe. This system, which will be demonstrated also, is viewed as a prototype commercial product. The 500 kWe-class PSOFC/MTG concept is described and performance estimates are presented.

Operating Experiences on Commercial Fuel Cell Units for Back Up Power Generation

2010 ◽  
Vol 7 (3) ◽  
Author(s):  
Mauro Scagliotti ◽  
Carmen Valli
Keyword(s):  
Steady State ◽  
Fuel Cell ◽  
Power Systems ◽  
Power System ◽  
Polymer Electrolyte Fuel Cell ◽  
System Response ◽  
Safety Issues ◽  
Endurance Testing ◽  
Endurance Tests ◽  
Power System Performance

Extensive residential demonstration programs and the needs for innovative and reliable back up power systems are driving the development and diffusion of small (<10 kWe) stationary fuel cell power systems. Low temperature polymer electrolyte fuel cell (PEFC) power systems are particularly suitable for back up and UPS applications due to short start up times, whereas for small cogenerative residential applications both PEFC and solid oxide fuel cells (SOFCs) are emerging as promising technologies. The technical and economical viabilities of fuel cell based systems have been already demonstrated for a few niche applications such as back up system with high autonomy. Nevertheless fuel cell technologies are not yet mature. Durability and reliability are of great concern and have to be specifically addressed. Real world experiences and extensive laboratory testing are paramount for the development of reliable products, as well as to harmonize and refine codes and standards required for the market entry. This paper presents and discusses the results of a 3 year experience on commercial PEFC 1 kWe units. Basic characterization, cycling, and steady state endurance testing data are analyzed herein with a focus on power system performance, reliability, and degradation issues. End user and system integrator testing approaches were applied. Power system response to load demand and electrical efficiency were measured following as much as possible the prescriptions of codes and standards. The influences of operating and environmental conditions on system efficiency were investigated as well. Positive results were achieved and, in particular, system availability resulted extremely high. Steady state long term endurance tests evidenced, however, critical durability and safety issues to be improved.

Analyzing Carbohydrate-Based Regenerative Fuel Cells as a Power Source for Unmanned Aerial Vehicles

2008 ◽  
Author(s):  
Olek Wojnar ◽  
Eric D. Swenson ◽  
Gregory W. Reich
Keyword(s):  
Fuel Cell ◽  
Power Systems ◽  
Power System ◽  
Unmanned Aerial Vehicles ◽  
Flight Control ◽  
Power Source ◽  
Waste Products ◽  
Aerial Vehicles ◽  
Primary Power ◽  
Long Endurance

Based on current capabilities, we examine the feasibility of creating a carbohydrate-based regenerative fuel cell (CRFC) as the primary power source for unmanned aerial vehicles (UAV) for long endurance missions where station keeping is required. The CRFC power system evaluated in this research is based on a closed-loop construct where carbohydrates are generated from zooxanthellae, algae which create excess carbohydrates during photosynthesis. The carbohydrates are then fed to a carbohydrate fuel cell where electric power is generated for the UAV’s propulsion, flight control, payload, and accessory systems. The waste products from the fuel cell, carbon dioxide and water, are used by the zooxanthellae to create more carbohydrates, therefore mass is conserved in the process of power generation. The overall goal of this research is to examine the potential of CRFCs as a viable power source for UAV systems, to look at scaling issues related to different vehicle sizes and missions, and to identify sensitivities in the CRFC system to different system parameters, indicating the areas where technology improvements may make CRFCs a viable technology. Through simulations, a UAV is sized to determine if greater than 24 hour endurance flight is possible and these results are compared to UAVs using more traditional photo-cell based power systems. The initial results suggest that CRFCs have potential as a power system for long endurance UAVs, and could offer significant improvements to the overall system performance. The final outcome of this research is to identify the most important areas for more detailed follow-on work in designing a production-ready CRFC power system for long endurance UAVs.

Markov Jump Linear System Analysis of a Microgrid Operating in Islanded and Grid Tied Modes

2020 ◽  
Author(s):  
Gilles Mpembele ◽  
Jonathan Kimball
Keyword(s):  
Monte Carlo ◽  
Power Systems ◽  
Power System ◽  
System Analysis ◽  
Differential Algebraic Equations ◽  
Algebraic Equations ◽  
Markov Jump ◽  
Numerical Application ◽  
Conditional Moments ◽  
Markov Jump Linear Systems

<div>The analysis of power system dynamics is usually conducted using traditional models based on the standard nonlinear differential algebraic equations (DAEs). In general, solutions to these equations can be obtained using numerical methods such as the Monte Carlo simulations. The use of methods based on the Stochastic Hybrid System (SHS) framework for power systems subject to stochastic behavior is relatively new. These methods have been successfully applied to power systems subjected to</div><div>stochastic inputs. This study discusses a class of SHSs referred to as Markov Jump Linear Systems (MJLSs), in which the entire dynamic system is jumping between distinct operating points, with different local small-signal dynamics. The numerical application is based on the analysis of the IEEE 37-bus power system switching between grid-tied and standalone operating modes. The Ordinary Differential Equations (ODEs) representing the evolution of the conditional moments are derived and a matrix representation of the system is developed. Results are compared to the averaged Monte Carlo simulation. The MJLS approach was found to have a key advantage of being far less computational expensive.</div>

Grasshopper Algorithm Optimized Fractional Order Fuzzy PID Frequency Controller for Hybrid Power Systems

2019 ◽  
Vol 12 (6) ◽  
pp. 519-531
Author(s):  
Deepak Kumar Lal ◽  
Ajit Kumar Barisal
Keyword(s):  
Power Systems ◽  
Power System ◽  
Fractional Order ◽  
Pid Controller ◽  
Load Frequency Control ◽  
Pid Controllers ◽  
Fuzzy Pid ◽  
Fuzzy Pid Controller ◽  
Hybrid Power ◽  
Increasing Demand

Background: Due to the increasing demand for the electrical power and limitations of conventional energy to produce electricity. Methods: Now the Microgrid (MG) system based on alternative energy sources are used to provide electrical energy to fulfill the increasing demand. The power system frequency deviates from its nominal value when the generation differs the load demand. The paper presents, Load Frequency Control (LFC) of a hybrid power structure consisting of a reheat turbine thermal unit, hydropower generation unit and Distributed Generation (DG) resources. Results: The execution of the proposed fractional order Fuzzy proportional-integral-derivative (FO Fuzzy PID) controller is explored by comparing the results with different types of controllers such as PID, fractional order PID (FOPID) and Fuzzy PID controllers. The controller parameters are optimized with a novel application of Grasshopper Optimization Algorithm (GOA). The robustness of the proposed FO Fuzzy PID controller towards different loading, Step Load Perturbations (SLP) and random step change of wind power is tested. Further, the study is extended to an AC microgrid integrated three region thermal power systems. Conclusion: The performed time domain simulations results demonstrate the effectiveness of the proposed FO Fuzzy PID controller and show that it has better performance than that of PID, FOPID and Fuzzy PID controllers. The suggested approach is reached out to the more practical multi-region power system. Thus, the worthiness and adequacy of the proposed technique are verified effectively.

scholarly journals Optimization of the Fuel Cell Renewable Hybrid Power System Using the Control Mode of the Required Load Power on the DC Bus

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1889 ◽  
Author(s):  
Nicu Bizon ◽  
Valentin Alexandru Stan ◽  
Angel Ciprian Cormos
Keyword(s):  
Energy Source ◽  
Fuel Cell ◽  
Power System ◽  
Control Mode ◽  
Variable Load ◽  
Hybrid Power System ◽  
Hybrid Power ◽  
Load Power ◽  
Load Demand ◽  
Dc Bus

In this paper, a systematic analysis of seven control topologies is performed, based on three possible control variables of the power generated by the Fuel Cell (FC) system: the reference input of the controller for the FC boost converter, and the two reference inputs used by the air regulator and the fuel regulator. The FC system will generate power based on the Required-Power-Following (RPF) control mode in order to ensure the load demand, operating as the main energy source in an FC hybrid power system. The FC system will operate as a backup energy source in an FC renewable Hybrid Power System (by ensuring the lack of power on the DC bus, which is given by the load power minus the renewable power). Thus, power requested from the batteries’ stack will be almost zero during operation of the FC hybrid power system based on RPF-control mode. If the FC hybrid power system operates with a variable load demand, then the lack or excess of power on the DC bus will be dynamically ensured by the hybrid battery/ultracapacitor energy storage system for a safe transition of the FC system under the RPF-control mode. The RPF-control mode will ensure a fair comparison of the seven control topologies based on the same optimization function to improve the fuel savings. The main objective of this paper is to compare the fuel economy obtained by using each strategy under different load cycles in order to identify which is the best strategy operating across entire loading or the best switching strategy using two strategies: one strategy for high load and the other on the rest of the load range. Based on the preliminary results, the fuel consumption using these best strategies can be reduced by more than 15%, compared to commercial strategies.

Analysis between graph-based and Power Transfer Distribution Factors (PTDF)-based model reduction methods in Electric Power Systems

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Diego A. Monroy-Ortiz ◽  
Sergio A. Dorado-Rojas ◽  
Eduardo Mojica-Nava ◽  
Sergio Rivera
Keyword(s):  
Power Systems ◽  
Power System ◽  
Model Reduction ◽  
Electrical Power ◽  
Schur Complement ◽  
Power Transfer ◽  
Electrical Power System ◽  
Admittance Matrix ◽  
Test Beds ◽  
Power Transfer Distribution Factors

Abstract This article presents a comparison between two different methods to perform model reduction of an Electrical Power System (EPS). The first is the well-known Kron Reduction Method (KRM) that is used to remove the interior nodes (also known as internal, passive, or load nodes) of an EPS. This method computes the Schur complement of the primitive admittance matrix of an EPS to obtain a reduced model that preserves the information of the system as seen from to the generation nodes. Since the primitive admittance matrix is equivalent to the Laplacian of a graph that represents the interconnections between the nodes of an EPS, this procedure is also significant from the perspective of graph theory. On the other hand, the second procedure based on Power Transfer Distribution Factors (PTDF) uses approximations of DC power flows to define regions to be reduced within the system. In this study, both techniques were applied to obtain reduced-order models of two test beds: a 14-node IEEE system and the Colombian power system (1116 buses), in order to test scalability. In analyzing the reduction of the test beds, the characteristics of each method were classified and compiled in order to know its advantages depending on the type of application. Finally, it was found that the PTDF technique is more robust in terms of the definition of power transfer in congestion zones, while the KRM method may be more accurate.

scholarly journals Series Compensation of Transmission Systems: A Literature Survey

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1717
Author(s):  
Camilo Andrés Ordóñez ◽  
Antonio Gómez-Expósito ◽  
José María Maza-Ortega
Keyword(s):  
Steady State ◽  
Power Systems ◽  
Power System ◽  
Case Studies ◽  
Electronic Devices ◽  
Literature Survey ◽  
Power Electronic ◽  
Transmission Systems ◽  
Series Compensation ◽  
Near Future

This paper reviews the basics of series compensation in transmission systems through a literature survey. The benefits that this technology brings to enhance the steady state and dynamic operation of power systems are analyzed. The review outlines the evolution of the series compensation technologies, from mechanically operated switches to line- and self-commutated power electronic devices, covering control issues, different applications, practical realizations, and case studies. Finally, the paper closes with the major challenges that this technology will face in the near future to achieve a fully decarbonized power system.

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