Study on the Polymer Membrane-Type Fuel Cell and Hybrid Hydrogenation Engine System Considering Improvement of Efficiency for Partial-Load Operation

2008 ◽  
Vol 5 (4) ◽  
Author(s):  
Shin’ya Obara ◽  
Itaru Tanno
Keyword(s):  
Fuel Cell ◽  
Threshold Value ◽  
Polymer Membrane ◽  
Solid Polymer ◽  
Engine Operation ◽  
Gas Engine ◽  
Partial Load ◽  
Membrane Type ◽  
Base Load ◽  
Type Fuel

Power demand patterns, such as for houses, fluctuate sharply. Therefore, if fuel cell cogeneration is installed in a house, partial-load operations with low efficiency frequently occur. On the other hand, if the hydrogen rate of hydrogenation gas-engine generation is increased at the time of low load, emission cleanup and brake thermal efficiency improve. So, in this paper, a hybrid cogeneration system that combines a hydrogenation gas engine and a solid polymer membrane-type fuel cell is proposed. So, operation of a fuel cell or a gas engine with the threshold value of load is investigated. In this paper, four systems were investigated by numerical analysis: independent hydrogenation gas-engine operation, solid polymer membrane-type fuel cell independent operation, that operates a fuel cell or a gas engine with the threshold value of load, and operation using a fuel cell to a base load. As a result, the operating method corresponding to a base load in polymer membrane-type fuel cell had the highest total efficiency. In this case, gas-engine generator (NEG) is operated corresponding to load fluctuation. Moreover, in the comparison results of carbon dioxide emissions, the hydrogenation operation of NEG achieved the best result.

Load Leveling of Fuel Cell System by Oxygen Concentration Control of Cathode Gas

2006 ◽  
Vol 4 (3) ◽  
pp. 238-247
Author(s):  
Shin’ya Obara
Keyword(s):  
Fuel Cell ◽  
Oxygen Concentration ◽  
High Efficiency ◽  
Water Electrolysis ◽  
Cell System ◽  
Solid Polymer ◽  
Power Load ◽  
Load Leveling ◽  
Membrane Type ◽  
Electric Power Load

The capacity reduction of a solid-polymer-membrane-type fuel cell (PEFC) with a reformer by load leveling and by improving the efficiency of part-load operation of the reformer is considered. The power generation efficiency of a fuel cell improves by supplying gas with a high oxygen concentration to the cathode. During periods of low electricity demand, the fuel cell is operated using reformed gas and air, and water electrolysis operation is also performed. When the electric power load is large, gases stored in cylinders are supplied to the fuel cell for operation. Using the proposed method, high efficiency operation and a reduction in the fuel cell capacity are possible.

Study of a Small-Scale Fuel Cell Cogeneration System with Methanol Steam Reforming Considering Partial Load and Load Fluctuation

2005 ◽  
Vol 127 (4) ◽  
pp. 265-271 ◽  
Author(s):  
S. Obara ◽  
K. Kudo
Keyword(s):  
Fuel Cell ◽  
Cost Estimation ◽  
Energy Cost ◽  
Electric Heater ◽  
Small Scale ◽  
Load Fluctuation ◽  
Partial Load ◽  
Cogeneration System ◽  
Conventional Systems ◽  
Type Fuel

Performance analysis and cost estimation are carried out for a cogeneration system consisting of a solid high-polymer-film-type fuel cell with a methanol reformer applied to individual houses. For the operation of the fuel cell under a partial load, a unique point of this system is the shifting of the driving point by the electric heater. Considering the annual energy cost for an average house in Sapporo, Japan, the energy cost of this system is shown to be 1.42 times that of conventional systems in which a cogeneration system is not installed.

A study of work and improve of water content in PEMFC with liquid cooling

2020 ◽  
Vol 6 (2) ◽  
pp. 8-21
Author(s):  
Konstantin V. Agapov ◽  
Dmitriy O. Dunikov ◽  
Kirill D. Kuzmin ◽  
Evgeniy V. Stoyanov
Keyword(s):  
Fuel Cell ◽  
Temperature Difference ◽  
Test Bench ◽  
Problem Area ◽  
Solid Polymer ◽  
Liquid Cooling ◽  
Current Voltage ◽  
Additional Resistance ◽  
Overall Performance ◽  
The Heat Balance

In this publication, in addition to focusing on the engineering component in creating our own test bench for trying various modes and the overall performance of solid polymer fuel cells with electric power of more than 2 kW, the features of the result of the operation of a liquid-cooled fuel cell in the field of heat transfer are displayed. It is known that its performance and service life depend on a properly tuned water and thermal balance of the fuel cell. The problem area is described in the insufficient moisture content of the supplied air to the fuel cell and the excess heat in the fuel cell. In this case, the negative consequence is that additional resistance to the rate of the electrochemical reaction is created, as a result of which the generated power decreases. A possible way to solve this problem is proposed: so, according to the heat balance equation, by increasing the temperature difference between the incoming and outgoing heat carrier, more heat energy can be removed. The temperature difference was achieved using a water-air radiator. The increased removal of thermal energy allowed the condensation of part of the moisture inside the fuel cell, maintaining the humidity and conductivity of the membrane, but not allowing flooding of the channels with liquid water, which otherwise could lead to a decrease in performance. During the tests, it was possible to increase the removed power by 321 w, which is 8.4% in excess of the maximum power. Based on the obtained experimental results, dependencies were constructed that are expressed by the current-voltage characteristic, power curve, the amount of heat removed by the water from the fuel cell, and a graph of the change in water temperature at the inlet and outlet of the fuel cell at various stages of operation.

scholarly journals A New Method to Determine the Impact of Individual Field Quantities on Cycle-to-Cycle Variations in a Spark-Ignited Gas Engine

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4136
Author(s):  
Clemens Gößnitzer ◽  
Shawn Givler
Keyword(s):  
Kinetic Energy ◽  
Flow Field ◽  
Turbulent Kinetic Energy ◽  
Negative Impact ◽  
Operating Conditions ◽  
Engine Operation ◽  
Gas Engine ◽  
Cycle Simulation ◽  
Simulation Results ◽  
The Impact

Cycle-to-cycle variations (CCV) in spark-ignited (SI) engines impose performance limitations and in the extreme limit can lead to very strong, potentially damaging cycles. Thus, CCV force sub-optimal engine operating conditions. A deeper understanding of CCV is key to enabling control strategies, improving engine design and reducing the negative impact of CCV on engine operation. This paper presents a new simulation strategy which allows investigation of the impact of individual physical quantities (e.g., flow field or turbulence quantities) on CCV separately. As a first step, multi-cycle unsteady Reynolds-averaged Navier–Stokes (uRANS) computational fluid dynamics (CFD) simulations of a spark-ignited natural gas engine are performed. For each cycle, simulation results just prior to each spark timing are taken. Next, simulation results from different cycles are combined: one quantity, e.g., the flow field, is extracted from a snapshot of one given cycle, and all other quantities are taken from a snapshot from a different cycle. Such a combination yields a new snapshot. With the combined snapshot, the simulation is continued until the end of combustion. The results obtained with combined snapshots show that the velocity field seems to have the highest impact on CCV. Turbulence intensity, quantified by the turbulent kinetic energy and turbulent kinetic energy dissipation rate, has a similar value for all snapshots. Thus, their impact on CCV is small compared to the flow field. This novel methodology is very flexible and allows investigation of the sources of CCV which have been difficult to investigate in the past.

Exergy Analysis of a Hybrid Micro Gas Turbine Fuel Cell System Based on Existing Components

2012 ◽  
Author(s):  
D. P. Bakalis ◽  
A. G. Stamatis
Keyword(s):  
Fuel Cell ◽  
Hybrid System ◽  
Exergy Analysis ◽  
Cell System ◽  
System Component ◽  
Utilization Factor ◽  
Fuel Cell Stack ◽  
Micro Gas Turbine ◽  
Partial Load ◽  
Set Up

A hybrid system based on an existing recuperated microturbine and a pre-commercially available high temperature tubular solid oxide fuel cell is modeled in order to study its performance. Individual models are developed for the microturbine and fuel cell generator and merged into a single one in order to set up the hybrid system. The model utilizes performance maps for the compressor and turbine components for the part load operation. The full and partial load exergetic performance is studied and the amounts of exergy destruction and efficiency of each hybrid system component are presented, in order to evaluate the irreversibilities and thermodynamic inefficiencies. Moreover, the effects of various performance parameters such as fuel cell stack temperature and fuel utilization factor are investigated. Based on the available results, suggestions are given in order to reduce the overall system irreversibility. Finally, the environmental impact of the hybrid system operation is evaluated.

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