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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean hydrogen and new energy society
Journal Basic Information
Journal DOI :
The Korean Hydrogen and New Energy Society
Editor in Chief :
Volume & Issues
Volume 22, Issue 6 - Dec 2011
Volume 22, Issue 5 - Oct 2011
Volume 22, Issue 4 - Aug 2011
Volume 22, Issue 3 - Jun 2011
Volume 22, Issue 2 - Apr 2011
Volume 22, Issue 1 - Feb 2011
Selecting the target year
A Study on the Performance and Operation Limit of Electrodialysis Cell for HI Concentration
Lee, Byung-Woo ; Jeong, Seong-Uk ; Cho, Won-Chul ; Kang, Kyoung-Soo ; Park, Chu-Sik ; Bae, Ki-Kwang ; Kim, Young-Ho ; Kim, Chang-Hee ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 749~758
The present work explores the performance and operation limit of electrodialysis cell for HI concentration in sulfur iodine thermochemical hydrogen production process, For this purpose, the electrodialysis cell was assembled with Nafion 117 as a PEM membrane and two activated carbon papers as the electrodes. HIx solution was prepared with composition of HI:
= 1: 0.5~2.5: 5.2 in molar ratio. The cell and its peripheral apparatus were placed in the specially designed convective oven in order to uniformly maintain the operation temperature. As operation temperature increased, the amount of water transport from anode to cathode increased, thus reducing HI molarity in catholyte. Meanwhile, the current efficiency was constant as about 90 %, irrespective of temperature change. The cell voltage increased with initial
mole ratio as well as anolyte to catholyte mole ratio. Moreover the cell voltage overshot took place within 10 h cell operation, which is due to the
precipitation inside the cell. From the analysis of
mole ratio in the anolyte, it is noted that operation limit (in
mole ratio) of the electrodialysis cell, arising from was measured to be 3.2, which is much lower than bulk solubility limit of 4.7.
Powder Synthesis and Membrane Deposition of BaCe
System for Hydrogen Separation Application
Kang, Kyung-Min ; Yun, Young-Hoon ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 759~764
Mixed-conducting oxide powders,
(SCY) powders have been prepared by a solid-state reaction method. Xray diffraction patterns of the prepared powders showed the sharp peaks of the
phases. The oxide powders that were prepared by attrition milling showed rather large particles and severe necking between particles in FE-SEM images as well as residual reactant (
) and secondary phases (
) in XRD patterns. The oxide powders prepared using ball milling showed particles under approximately 500 nm and typical XRD patterns of the
phases. Ceramic membranes of the
phases were fabricated by the aerosol deposition method using the oxide powders synthesized.
Effect of Heat Treatment on the Start-up Performance for Anaerobic Hydrogen Fermentation of Food Waste
Lee, Chae-Young ; Lee, Se-Wook ; Hwang, Sun-Jin ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 765~771
This study was conducted to investigate the effect of heat treatment on the start-up performance for anaerobic hydrogen fermentation of food waste. The result showed that hydrogen production was
/mol hexose with heat-treatment of food waste at
for 60 min whereas it was
/mol hexose without heat-treatment of one. The heat treatment of food waste enhanced hydrogen yield due probably to the increase of hydrolysis as well as the decrease of non-hydrogen fermentation microorganisms. The removal efficiency of carbohydrate in reactors regardless of heat treatment of food waste maintained over 90%. The hydrogen conversion efficiency from food waste was 1.7-6.3% with heat-treatment whereas it was 0.7-4.5% without heat-treatment. At the time of switchover from batch to continuous operation, lactate concentration was high compared to the n-butyrate concentration in anaerobic hydrogen fermentation reactor without heat-treatment. Anaerobic hydrogen fermentation of food waste with heat treatment was stable in start-up periods because lactate concentration could be maintained at a relatively low compared to n-butyrate concentration due to the decrease of non-hydrogen fermentation microorganisms.
The Study of Effect of Steam on Partial Oxidation for Model Biogas using 3D Matrix Reformer
Lim, Mun-Sup ; Chun, Young-Nam ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 772~779
New type of syngas generator based on the partial oxidation of biogas in volumetric permeable matrix reformers was suggested as an effective, adaptable and relatively simple way of syngas and hydrogen production for various low-scale applications. The use of biogas as an energy source reduces the chance of possible emission of two greenhouse gases,
, into the atmosphere at the same time. Its nature of being a reproducible energy source makes its use even more attractive. Parametric screening studies were achieved as air ratio, biogas component ratio, input gas temperature, Steam/Carbon ratio. As the air ratio was low, the production of the hydrogen and carbon monoxide increased in the condition that 3D matrix reformer maintains the stable driving. As it was the simulation biogas in which the carbon dioxide content is high, the flammable range became narrow. And the flammable range was extended if the injected gas was preheated. The stable driving was possible in the low air ratio. The amount of hydrogen production was increased as S/C ratio increased.
Evaluation of Hydrogenation Behavior of MgH
-Graphene Composites by Mechanical Alloying
Lee, Soo-Sun ; Lee, Na-Ri ; Kim, Kyeong-Il ; Hong, Tae-Whan ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 780~786
Mg hydride had high hydrogen capacity (7.6%), lightweight and low cost materials and it was promising hydrogen storage material at high temperature. However, commercial applications of the Mg hydride are currently hindered by its high absorption/desorption temperature, and very slow reaction kinetics. one of the approaches to improve the kinetic is
intermixed with carbon. And it shows that carbon and carbon allotropes have a beneficial effect on hydrogen sorption in Mg. The graphene is a kind of carbon allotropes which is easily desorbed reaction at low temperatures because its reaction is exothermic. In this work, the effect of graphene concentration on the kinetics of Mg hydrogen absorption reaction was investigated. The
-Graphene composites has been prepared by hydrogen induced mechanical alloy (HIMA). The synthesized powder was characterized by XRD and simultaneous TG, DSC analysis. The hydrogenation behaviors were evaluated by using a sievert's type automatic PCT apparatus. In this research, results of kinetic profiles exhibit hydrogen absorption rate of
-5wt.% and 10wt.% graphene composite, as 1.25wt.%/ms, 10.33wt.%/ms against 0.88wt.%/ms for
alone at 473K.
Hydriding and Dehydriding Rates of Magnesium-Nickel Alloy Fabricated by Milling under Hydrogen
Song, Myoung-Youp ; Baek, Sung-Hwan ; Park, Hye-Ryoung ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 787~793
A 76.5wt%Mg - 23.5wt%Ni (Mg-23.5Ni) sample was prepared by reactive mechanical grinding (RMG) and its hydriding and dehydriding properties were then investigated. Activation of the Mg-23.5Ni sample was completed only after two hydriding (under 12 bar
) - dehydriding (under 1.0 bar
) cycles at 593K. The reactive mechanical grinding of Mg with Ni is considered to facilitate nucleation and shorten diffusion distances of hydrogen atoms. After hydriding - dehydriding cycling, the Mg-23.5Ni sample contained Mg2Ni phase.
An Analysis on Charateristics of Separate Oiling to Reduce Oil Consumption for a 2 Stroke Free-Piston H
Byun, Cahng-Hee ; Baek, Dae-Ha ; Lee, Jong-Tae ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 794~799
In order to reduce the oil consumption for a 2 stroke free piston hydrogen fueled engine, the behaviors of residual lubricant oil of the cylinder wall surface were visualized and oil mass emitted into exhaust port was measured by using research engine with cross-head and eccentric crankshaft. As the results, it was shown that characteristics of residual lubricant oil such as oil thickness and distribution were remarkably different from a conventional 4 stroke engine. It was also analyzed that these tendencies relied on the configuration and installed position of the exhaust port, piston pin boss and so on.
Performance Comparison of Integrated Reactor with Steam Reforming and Catalytic Combustion using Anode Off-Gas for High Temperature Fuel Cells
Ghang, Tae-Gyu ; Sung, Hae-Jung ; Lee, Sang-Min ; Ahn, Kook-Young ; Kim, Yong-Mo ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 800~809
The reaction characteristics of an integrated reactor with steam reformer and catalytic combustor using anode offgas for high temperature fuel cells such as MCFC and SOFC have been experimentally investigated in the present study. The coupled reactor had a coaxial cylindrical shape, and the inner and the outer tube was packed with combustion catalysts and reforming catalysts, respectively. Thus, the endothermic steam reforming could proceed by absorbing heat from catalytic combustion of anode offgas. Results show that increasing inlet temperature and decreasing excess air ratio increased the reformer temperature, which led to the increase in
yield. The reforming performance for SOFC conditions was better than that for MCFC conditions since the composition of flammable components became smaller for MCFC cases. Measured reformate composition under various test conditions correlated well with thermal equilibrium composition.
Study on the Evaluation Method of Electrical Isolation Property for Hydrogen Fuel Cell Vehicle
Lee, Ki-Yeon ; Kim, Dong-Ook ; Kim, Hyang-Kon ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 810~818
This paper analyzed the suitability about the isolation performance criteria which was based on human impedance and effect of current in IEC 60479-1 on the safety of human being was examined. The method of evaluation by megger and DC voltmeter was analyzed. The differences of isolation performance according to design of high-voltage system were analyzed. The factors which affect the insulation performance were analyzed for HFCV, EV, HEV, etc. through analysis of the isolation performance evaluation method. Finally, design for improved isolation performance was proposed.
Experimental Study on the Characteristics of Heat Exchanger of 1 kW PEMFC System for UAV
Kang, Sang-Gyu ; Kim, Byung-Jun ; Kim, Han-Seok ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 819~826
The proton exchange membrane fuel cell (PEMFC) is regarded as the most promising alternative power sources for unmanned aerial vehicle (UAV) due to its high energy density and silent operation. Since there are many load changes during UAV flight, thermal management is one of the important factor for the performance of PEMFC. In order to reduce the UAV weight for the stable operation of UAV, thermal management system (TMS) studied in this work does not use the fan but use the air flowing into UAV by UAV flight. In order to develop the passive type heat exchanger (HEX) for 1kW PEMFC, four types of HEXs are fabricated and their cooling performances are compared. The parametric study on the cooling performance of HEXs has performed with the variation of operating parameters such as mass flow rates and inlet temperature of air and coolant. Type 4 has the best performance in every case. This study can be helpful to achieve the optimal design of HEX for PEMFC powered UAV.
Thermal Curing and Electrical Properties of Epoxy/Graphite/Expanded Graphite Composite for Bipolar Plate of Pemfc
Lee, Jae-Young ; Lee, Hong-Ki ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 827~834
Epoxy/graphite/expanded graphite composites have been prepared in various weight ratios and thermal degradation and electrical properties were estimated in order to use for the bipolar plate materials in PEMFC. Thermogravimetric analysis (TGA) showed that the epoxy/graphite system cured by a curing agent GX-533 was most proper because its weight loss until
at which PEMFC would be operated was 0.3 wt%, and differential scanning calorimetry (DSC) analysis showed its cure temperature would be sufficient at
. The activation energy for the cure reaction was 132.0 kJ/mol and the pre-exponential factor was
. Electrical conductivity on the surface of the bipolar plate prepared under a pressure of 200
was increased from 4 to 25
by increasing expanded graphite (EG) content from 50 phr to 90 phr. The percolation threshold was initiated around 75 phr and the corrosion rate at 80 phr was 1.903
A Study on The Control of Humidification and Dew Condensation by On/Off Control
Park, Dea-Heum ; Kim, Du-Hee ; Kim, Kyoung-Hoon ; Jung, Young-Guan ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 835~841
The humidification is essential for performance enhancement of the electrolysis of PEMFC because proton conductivity depends on hydration of the proton exchange membrane. In this study, the humidification experiment did about On/Off control the humidification and dew condensation for PEMFC by using of the membrane humidifiers. As the results, it was possible to approximation control of the humidity by using of the solenoid valve On/Off control on the membrane humidifier. Also the problem on the dew condensation was resolved by approximation humidity control through solenoid valve On/Off control and the removal of the dew condensation in the flow channel was verified through visualization experiment.
Analysis for Performance Deviation of Individual Cells in a Multi-Cell Test System for Rapid-Screening of Electrode Materials in PEMFCs
Zhang, Yan ; Lee, Ji-Jung ; Park, Gyung-Se ; Lee, Hong-Ki ; Shim, Joong-Pyo ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 842~851
A multi-cell test system with 25 independent cells is used to test different electrode materials simultaneously for polymer electrolyte membrane fuel cells (PEMFCs). Twenty-five segmented membrane electrode assemblies (MEAs) having the same or different Pt-loading are prepared to analyze the performance deviation of cells in the multi-cell test system. Improvements in the multi-cell test system are made by ensuring that the system performs voltage sensing for the cells individually and inserting optimum gaskets between the MEAs and the graphite plates. The cell performances are improved and their deviations are significantly decreased by these modifications. The performance deviations changed according to various cell configurations because the operating conditions of the cells, such as the gas flow and concentration, differed. This cell system can be used to test multiple electrodes simultaneously because it shows relatively uniform performance under the same conditions as well as linear correlation with various catalyst loadings.
Experimental Study on the Mutual Influence of Thermal Management System for Hydrogen Fuel Cell Vehicle
Lee, Moo-Yeon ; Won, Jong-Phil ; Cho, Choong-Won ; Lee, Ho-Seong ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 852~858
This paper is aiming to estimate the mutual influence of the stack cooling performances with the operation modes of the thermal management system for the hydrogen fuel cell vehicles. The heat capacity of the thermal management system was measured by varying the operating modes such as stack cooling heat exchanger only (Mode 1), stack cooling and electric devices cooling heat exchangers (Mode 2), and stack cooling and electric devices cooling heat exchangers with an operation of the condenser (Mode 3).As the results, Performance of the thermal management system (TMS) at Mode 3 decreased up to 34.0%, compared with the result of the Mode 1. In addition, in order to optimize the performance of TMS, the entropy change of stack cooling heat exchanger using irreversibility analysis technique was analyzed with the relationship between entropy generation and entering air velocity of the thermal management system.
Effect of Composite Sandwich Endplates on the Improvement of Cold Start Characteristics for PEMFC
Suh, Jung-Do ; Ko, Jae-Jun ; Ahn, Byung-Ki ; Yu, Ha-Na ; Lee, Dai-Gil ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 859~867
The cold start problem is one of major obstacles to overcome for the commercialization of fuel cell vehicles. However, the cold start characteristics of fuel cell systems are very complicated since various phenomena, i.e. ice-blocking, electro-chemical reactions, heat transfer, and defrosting of BOP components, are involved in them. This paper presents a framework to approach the problem at a full stack scale using Axiomatic Design (AD). It was characterized in terms of Functional Requirements (FRs) and Design Parameters (DPs) while their relations were established in a design matrix. Considering the design matrix, the endplates should have low thermal conductivity and capacity without increase in weight or decrease in structural stiffness. Consequently, composite sandwich endplates were proposed and examined both through finite element analyses and experiments simulating cold start conditions. From the examinations, it was found that the composite sandwich endplates significantly contributed to improving the cold start characteristics of PEMFC.
Parallel Computing Simulation of Large-Scale Polymer Electrolyte Fuel Cells
Gwak, Geon-Hui ; Chippar, Purushothama ; Kang, Kyung-Mun ; Ju, Hyun-Chul ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 868~877
This paper presents a parallel computing methodology for polymer electrolyte fuel cells (PEFCs) and detailed simulation contours of a real-scale fuel cell. In this work, a three-dimensional two-phase PEFC model is applied to a large-scale 200
fuel cell geometry that requires roughly 13.5 million grid points based on grid-independence study. For parallel computing, the large-scale computational domain is decomposed into 12 sub-domains and parallel simulations are carried out using 12 processors of 2.53 GHz Intel core i7 and 48GB RECC DDR3-1333. The work represents the first attempt to parallelize a two-phase PEFC code and illustrate two-phase contours in a representative industrial cell.
Effect of Flow Uniformity Device on the Catalytic Combustor for 5 kW High Temperature Fuel Cell System
Lee, Sang-Min ; Woo, Hyun-Tak ; Ahn, Kook-Young ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 878~883
Effect of flow uniformity on the reaction characteristics of a catalytic combustor for high temperature fuel cell system has been experimentally investigated in the present study. One of the most important factor in designing catalytic combustion is to avoid hot spot in catalysts. In this regard, it is very important to secure flow uniformity of combustor inlet. A couple of perforated plates were applied at the front of catalyst region as flow uniformity device with minimal pressure drop. Results show that the velocity and temperature profile became more uniform when applying the flow uniformity device. CO and
emissions at the combustor exit were decreased and the average exit temperature was slightly increased with the flow uniformity device.
Chemical Looping Combustion Characteristics of Coal and Char in a Batch Type Fluidized Bed Reactor
Ryu, Ho-Jung ; Hyun, Ju-Soo ; Kim, Young-Joo ; Park, Yeong-Seong ; Park, Moon-Hee ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 884~894
Effects of temperature, volatile content, particle diameter and solid input weight were investigated in the batch fluidized bed reactor using OCN703-1100 particle as oxygen carrier and Roto coal and char as fuels. Two solid fuels represented the best reactivity at different temperature,
for Roto coal and
for char, respectively. However, we selected
as the best operating temperature because the improvement of reactivity of char at
was negligible. Char represented better reactivity than Roto coal because char contains low volatile than Roto coal. For both solid fuels, reactivities were improved with increasing of the particle diameter. These results were explained by solid mixing tests in a transparent fluidized bed using two char particles having different particle size ranges and OCN703-1100 particle. The bigger particle showed better solid mixing with OCN703-1100 particle, and therefore, represented better reactivity. For both solid fuels, reactivities were improved with increasing of the solid input weight within the experimental conditions of this study because the weight of coarse particles increased with the solid input weight increased, and therefore, these coarse particles can mix well with the oxygen carrier.
A Study about the Effects of EGR Stratification on Reducing the Pressure RIse Rate of DME HCCI Combustion
Lim, Ock-Taeck ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 895~904
Stratified charge has been thought as one of the ways to avoid a sharp pressure rise on HCCI combustion. The purpose of this study is to evaluate the potential of stratified charge for reducing PRR on HCCI combustion. The pre-mixture with thermal, mixing and EGR stratifications is charged in Rapid Compression Machine. After that, the pre-mixture is compressed and in that process, in-cylinder gas pressure and temperature are analyzed. Additionally numerical calculation with multi-zones modeling is run to know the potential of stratified charge for reducing PRR.
Catalytic Activity Tests in Gas-Liquid Interface over Cu-ZnO/Al
Catalyst for High Pressure Water-Gas-Shift Reaction
Kim, Se-Hun ; Park, No-Kuk ; Lee, Tae-Jin ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 905~912
In this study, the novel concept catalytic reactor was designed for water-gas shift reaction (WGS) under high pressure. The novel concept catalytic reactor was composed of an autoclave, the catalyst, and liquid water. Cu-ZnO/
as the low temperature shift catalyst was used for WGS reaction. WGS in the novel concept catalytic reactor was carried out at the ranges of 150~
and 30~50 atm. The liquid water was filled at the bottom of the autoclave catalytic reactor and the catalyst of pellet type was located at the gas-liquid water interface. It was concluded that WGS reaction occurred over the surface of catalysts partially wetted with liquid water. The conversion of CO for WGS was also controlled with changing content of Cu and ZnO used as the catalytic active components. Meanwhile, the catalyst of honey comb type coated with Cu-ZnO/
was used in order to increase the contact area between wet-surface of catalyst and the reactants of gas phase. It was confirmed from these experiments that
/CO ratio of the simulated coal gas increased from 0.5 to 0.8 by WGS at gas-liquid water interface over the wet surface of honey comb type catalyst at
and 50 atm.
Analysis of Slag Behavior near the Slag Tap in an Entrained Flow Coal Gasifier
Chung, Jae-Hwa ; Chi, Jun-Hwa ; Lee, Joong-Won ; Seo, Seok-Bin ; Kim, Ki-Tae ; Park, Ho-Young ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 913~924
A steady-state analysis has been conducted to predict the behavior of the slag layer in the entrained-flow slagging coal gasifier. The analysis takes into consideration the composition dependent slag properties such as density, viscosity, heat capacity, thermal conductivity, and temperature of critical viscosity. The amount of added flux to the design coal and the variation of syngas temperature inside the gasifier have been adopted as calculation parameters. The predicted results are the local thickness of the molten and the solid slag layers, and the slag viscosity and the velocity distribution across the molten slag layer along the gasifier wall near the slag tap.
Production of DME from CBM by KOGAS DME Process
Cho, Won-Jun ; Mo, Yong-Gi ; Song, Taek-Yong ; Lee, Hyen-Chan ; Baek, Young-Soon ; Denholm, Douglas ; Ko, Glen ; Choi, Chang-Woo ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 925~933
The traditional feedstock for dimethyl ether (DME) has been natural gas obtained by pipeline from a nearby natural gas or oil field. This report focuses on other feedstock: Coal bed methane (CBM). The resource availability and suitability of CBM for DME manufacturing have been investigated. CBM in a short time has become an important industry, providing an abundant clean-burning fuel and also suggesting as a feedstock for gas industry. The use of CBM will have very little impact on the KOGAS' DME process design and economics up to 50 vol% of
in the CBM source. Many of the CBM sources in Asia are high in
, but pose no difficulties for the KOGAS' DME plant. Since tri-reformer requires substantial
in its feed, no
removal from the CBM feed is needed. The
in the CBM means that less
needs to be recycled from the downstream in the process.
Characteristics of Low NOx Plasma Burner Incorporating with Rotating Arc Plasma
Kim, Kwan-Tae ; Kang, Hee-Seok ; Lee, Dae-Hoon ; Song, Young-Hoon ; Park, Jae-Eon ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 934~941
Characteristics of low NOx burner is investigated. Low NOx burner introduced in this paper adopts two staged combustion with plasma burner for the 1st stage combustion. Extensive parametric tests were done to figure out the effect of burner stoichiometry, staged thermal load, electric power for plasma generation. Overall NOx production by burner shows effective reduction by adopting plasma staged burner. and the aspects depends on the fuel stoichiometry of 1st stage burner or operating condition of plasma burner. It is promising to use plasma burner as an alternative tools of low NOx burner technology.
Performance Test of Supercharger for Vehicle using Solar Cell
Ko, Kwang-Ho ;
Transactions of the Korean hydrogen and new energy society, volume 22, issue 6, 2011, Pages 942~948
The performance of a supercharger for vehicle using solar cell attached on the exterior of a car, an auxiliary battery, and an air compressor was evaluated in this study. This supercharger is composed of a solar cell of 40W, a battery of 60 Ah, an air compressor of 17 A, 8
and an air tank of 8L. It takes about 6 days to charge the battery with the solar cell and the high pressure air of 8L can be supplied about 70 times to engine intake with this battery. The intake pressure increased by about 20~40% with this supercharger. The vehicle power and accelerating performance are enhanced by 87% and 50% each in the low speed range. But the performance improved little in the high speed range because of the rather constant flow rate of air supplied by this type of supercharger.