Study of Efficiency Improvements in a Fuel-Cell-Powered Vehicle Using Water Electrolysis by Recovering Regeneration Energy and Avoiding Partial Load Operation

2005 ◽  
Vol 2 (3) ◽  
pp. 202-207 ◽  
Author(s):  
S. Obara ◽  
K. Kudo
Keyword(s):  
Energy Efficiency ◽  
Fuel Cell ◽  
Load Condition ◽  
Water Electrolysis ◽  
Maximum Output ◽  
Storage Mechanism ◽  
Vehicle Operation ◽  
Partial Load ◽  
Drive Motor ◽  
Low Efficiency

Improvements in efficiency of a fuel-cell-powered vehicle have been studied using water electrolysis as the energy storage mechanism. Three methods are proposed for this purpose: 1. The reformer and fuel cell are divided into two or more units, and the maximum output of each unit is set to be small, which reduces the partial load operation, 2. all the fuel cell units are operated above the low efficiency partial load condition and excess electricity is supplied to another fuel cell unit to generate hydrogen and oxygen by water electrolysis, and these gases are compressed and stored, and arbitrary fuel cell units are supplied and they generate electricity, 3. deceleration periods perform water electrolysis of the fuel cell units using the electric power generated by the drive motor, and both gases are compressed and they store in each cylinder. The LA4 cycle (EPA urban dynamometer schedule) was introduced for the vehicle operation. The energy saving effects of the abovementioned methods were studied and were shown to increase the energy efficiency by 1.23 to 1.72 times compared to that for the conventional method.

Installation Plan of a Fuel Cell Microgrid System Optimized by Maximizing Power Generation Efficiency

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Shin’ya Obara ◽  
Itaru Tanno
Keyword(s):  
Fuel Cell ◽  
Urban Area ◽  
Power Plants ◽  
High Energy ◽  
Gas Production ◽  
Proton Exchange ◽  
Generation Efficiency ◽  
Partial Load ◽  
Low Efficiency ◽  
Cooperation System

If energy-supplying microgrids can be arranged to operate with maximal efficiency, this will have a significant influence on the generation efficiency of the grid and will reduce greenhouse gas production. A means of optimizing the microgrid needs to be developed. Moreover, microgrids that use proton exchange membrane-type fuel cells (PEM-FCs) may significantly reduce the environmental impact when compared with traditional power plants. The amount of power supplied to the grid divided by the heating value of the fuel is defined as the system generation efficiency. The authors find that when a set of PEM-FCs and a natural gas reformer are connected to the microgrid in an urban area, the annual generation efficiency of the system slightly exceeds 20%. When a PEM-FC follows the electricity demand pattern of a house, it operates at a partial load most of the time, resulting in a low efficiency of the microgrid. A method of improving the generation efficiency of a fuel cell microgrid is proposed, where a supply system of power and heat with a high energy efficiency are constructed. In this paper, a method of installing two or more microgrids is proposed (known as the partition cooperation system). The grids can be connected in an urban area to maximize generation efficiency. Numerical analysis shows that the system proposed in this paper (which has an annual generation efficiency of 24.6–27.6%) has a higher generation efficiency than conventional PEM-FC systems (central generating systems have annual generation efficiencies of 20.6–24.8%).

Installation Plan of a Fuel Cell Cogeneration System

2014 ◽  
pp. 103-135
Keyword(s):  
Fuel Cell ◽  
Power Plants ◽  
Water Electrolysis ◽  
Cell Network ◽  
System A ◽  
Partial Load ◽  
Exhaust Heat ◽  
Cogeneration System ◽  
Cell Energy ◽  
Residential Cogeneration

This chapter consists of two sections, ‘Installation Plan of a Fuel Cell Microgrid System Optimized by Maximizing Power Generation Efficiency’ and ‘Fuel Cell Network with Water Electrolysis for Improving Partial Load Efficiency of a Residential Cogeneration System.’ A microgrid that use PEFC may significantly reduce the environmental impact when compared with traditional power plants. The 1st section investigates what occurs when a set of PEFCs and a natural gas reformer are connected to the microgrid in an urban area. In the 2nd section, a fuel cell energy network which connects hydrogen and oxygen gas pipes, electric power lines and exhaust heat output lines of the PEFC cogeneration for individual houses is analyzed.

scholarly journals Power Matching and Energy Efficiency Improvement of Hydraulic Excavator Driven with Speed and Displacement Variable Power Source

2019 ◽  
Vol 32 (1) ◽  
Author(s):  
Lei Ge ◽  
Long Quan ◽  
Xiaogang Zhang ◽  
Zhixin Dong ◽  
Jing Yang
Keyword(s):  
Energy Efficiency ◽  
Dynamic Performance ◽  
Load Condition ◽  
Power Source ◽  
Test System ◽  
Hydraulic Excavator ◽  
Idle Period ◽  
Partial Load ◽  
Variable Power ◽  
Working Performance

AbstractMobile machinery energy efficiency and emission pollution are the national and worldwide issues. This paper contributes in solving these problems by applying a speed variable power source. Unfortunately, almost all of the speed variable systems have the dynamic response problem when the motor starts with full load or heavy load. To address this problem, a hydraulic accumulator is used to balance the load of the power source for assisting starting of the motor and a matching method combined with speed and displacement control of the pump is proposed to improve the energy efficiency and dynamic performance simultaneously under different working conditions. Also, the power source/valve combined control strategy of an independent metering system is designed to realize flow matching of the whole system. Firstly, a test system is established to study the dynamic performance and energy efficiency of the speed variable power source with an auxiliary accumulator. Working performance and energy consumption of the power source under different rotating speeds and different loads are studied. And then, the hydraulic excavator test rig with the proposed system is constructed. Furthermore, the working performance of the excavator with the speed-fixed and speed-variable strategy are studied comparatively. Results show that, compared with fixed-speed strategy, the electric power consumption during the idle period and partial load condition can be reduced about 2.05 kW and 1.37 kW. The energy efficiency of speed variable power source is about 40%‒71%, which is higher than that of the fixed-speed power source by 3%–10%.

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.

Storage Mechanism of Processing Magnanimity Small Files Applying HDFS Architecture

2013 ◽  
Vol 765-767 ◽  
pp. 1614-1617
Author(s):  
Wang Xin ◽  
Jun Ma
Keyword(s):  
Reading Time ◽  
New Method ◽  
Storage Mechanism ◽  
Application Architecture ◽  
Reading Efficiency ◽  
Low Efficiency

Pointing at the low efficiency problem of I/O operations of small files using HDFS application architecture, this article proposes a new method, that is, add disk buffer on DataNode to reduce addressing time of reading small files, and thus reduce reading time, and reduce the stress bringed by frequent NameNode access, so as to optimize the reading efficiency of small files. Experiment results show that the design programme is feasible, and adding disk buffer benefits for increasing efficiency of processing small files applying HDFS.

Energieeffizienz beim Spanen/Energy efficiency at machining - Investigations about the influence of minimun quantity lubrication (MQL) at final cutting

2017 ◽  
Vol 107 (05) ◽  
pp. 352-358
Author(s):  
S. Prof. Simon ◽  
S. Wichmann ◽  
A. Brill
Keyword(s):  
Energy Efficiency ◽  
Minimum Quantity Lubrication ◽  
Stress Conditions ◽  
Cutting Performance ◽  
Workpiece Material ◽  
Load Range ◽  
University Of Technology ◽  
Partial Load ◽  
Longitudinal Turning

Von der Brandenburgischen Technischen Universität (BTU) sind in Zusammenarbeit mit der TU Liberec Untersuchungen zur Verbesserung der Energieeffizienz an spanenden Werkzeugmaschinen durchgeführt worden. Im Gegensatz zu bereits durchgeführten Untersuchungen wurde der Fokus hier auf das Belastungsverhalten im Teillastbereich gerichtet. Die durchgeführten Untersuchungen beschränkten sich auf das Längsdrehen mit geringen Schnitttiefen. Als Werkstoffe kamen ein Baustahl und ein Vergütungsstahl zum Einsatz. Durch die Bestimmung der Leerlaufleistung der verwendeten Drehmaschine waren tatsächliche Aussagen über die Schnittleistung möglich. Für das Ermitteln des Wirkungsgrades wurden auch die Schnittleistungen bei verschiedenen Drehzahlen aufgenommen. Alle weiteren Spanungsbedingungen blieben für die Untersuchungen konstant. Im Ergebnis der Untersuchung bestätigte sich das Potenzial der Minimalmengenschmierung. Der Wirkungsgrad verbesserte sich durchschnittlich um 5 %. Beachtenswert ist der Einfluss des Einstellwinkels. Hier liegt das Optimierungspotenzial der Energieeffizienz in Summe bei 14 %. Die Untersuchungen ergaben weiterhin eine hohe Korrelation von Spanungsbedingungen, Werkstückwerkstoff und verwendetem Schmiermittel.   The Brandenburg University of Technology has carried out investigations in cooperation with the technical University of Liberec to improve the energy efficiency of cutting machine tools. In contrast to investigations already carried out, the focus here was on the loading behavior in the partial load range. The investigations carried out were limited to longitudinal turning with low cutting depths. A structural steel and a tempering steel were used as materials. By determining the no-load power of the used lathe, actual statements about the cutting performance were possible. For the determination of the efficiency, the cutting performance was recorded at different speeds. All further stress conditions remained constant for the investigations. As a result of the investigation, the potential of minimum quantity lubrication was confirmed. The efficiency improved by an average of 5 %. The influence of the angle of setting was remarkable. The optimization potential of energy efficiency was at 14 %. The investigations also revealed a high correlation between stress conditions, workpiece material and lubricant used.

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