• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.1
• /
• pp.24-31
• /
• 2002

An experimental study was conducted to investigate the effects of EGR (Exhaust Gas Recirculation) variables on performance and emission characteristics in a 2-liter 4-cylinder spark-ignition LPG fuelled engine. The effects of EGR on the reduction of thermal loading at exhaust manifold were also investigated because the reduced gas temperature is desirable for the reliability of an engine in light of both thermal efficiency and material issue of exhaust manifold. The steady-state tests show that the brake thermal efficiency increased and the brake specific fuel consumption decreased with the increase of EGR rate in hot EGR and with the decrease of EGR temperature in case of cooled EGR, while the stable combustion was maintained. The increase of EGR rate or the decrease of EGR temperature results in the reduction of NOx emission even in the increase of HC emission. Furthermore, decreasing EGR temperature by $180^{\circ}C$ enabled the reduction of exhaust gas temperature by $15^{\circ}C$ in cooled EGR test at 1600rpm/370kPa BMEP operation, and consequently the reduction of thermal load at exhaust. The optimization strategy of EGR application is to be discussed by the investigation on the effect of geometrical characteristics of EGR-supplying pipe line.

• 한국연소학회:학술대회논문집
• /
• 2001.11a
• /
• pp.83-89
• /
• 2001

Most technologies of reduction process used in the heat treatment of existent metal products are related to metals applied to bolts and parts of automobiles, and nonmetal such as copper. Heating conditions and reduction gases produced in above processes depend on types of products to be treated thermally but heating systems employ electricity commonly and the reduction gases are separated into additional production equipment and a gas dryer and inefficiently provided into the system. Electrical heating system has the advantage of convenient temperature-control but is not economical because of disadvantages of high electricity-running cost and extra installation cost of a transformer. Accordingly, development of the system which has economical heating mode in which provision of reduction gas and heating conditions are unified is necessary for improvement of economy and efficiency in current reduction processes. This study aimed to develop a new advanced heat treatment furnace using catalytic combustion. thereby minimizing the cost during heating, supplying heat and reductive gas at the same time and controlling operating condition freely by changing electrical heating system to heating system by the gas combustion and regeneration of wasted heat.

• Environmental Engineering Research
• /
• v.18 no.3
• /
• pp.191-197
• /
• 2013

Republic of Korea announced the reduction target to be around 30% of business as usual greenhouse gas emissions by 2020. College campuses were ranked at the 5th of high energy consumption areas in the building sectors. Target management scheme was designed to set greenhouse gas emissions target including several college campuses. Previous studies showed the amount of greenhouse gas emissions with several assumptions such as the applications of renewable energy systems and light emitting diode lamps, etc. Long-range Energy Alternatives Planning model was utilized to simulate future greenhouse gas emissions. This study sets standard model labs for energy saving action programs by applying guidance studies. It has been deduced that energy saving action programs was responsible for reducing 949.5 kWh for each standard model lab and the total reduction of all 59 model labs in the Engineering College building has been calculated to 56,020.5 kWh. The objective of the study is to provide guidelines on standard model laboratory for greenhouse gas emissions reduction on the campus.

• Journal of Microbiology and Biotechnology
• /
• v.20 no.3
• /
• pp.615-621
• /
• 2010

The viability of low-temperature sulfate reduction with hydrogen as electron donor was studied with a bench-scale gas-lift bioreactor (GLB) operated at $9^{\circ}C$. Prior to the GLB experiment, the temperature range of sulfate reduction of the inoculum was assayed. The results of the temperature gradient assay indicated that the inoculum was a psychrotolerant mesophilic enrichment culture that had an optimal temperature for sulfate reduction of $31^{\circ}C$, and minimum and maximum temperatures of $7^{\circ}C$ and $41^{\circ}C$, respectively. In the GLB experiment at $9^{\circ}C$, a sulfate reduction rate of 500-600 mg $l^{-1}d^{-1}$, corresponding to a specific activity of 173 mg ${SO_4}^{2-}g\;VSS^{-1}d^{-1}$, was obtained. The electron flow from the consumed $H_2$-gas to sulfate reduction varied between 27% and 52%, whereas the electron flow to acetate production decreased steadily from 15% to 5%. No methane was produced. Acetate was produced from $CO_2$ and $H_2$ by homoacetogenic bacteria. Acetate supported the growth of some heterotrophic sulfate-reducing bacteria. The sulfate reduction rate in the GLB was limited by the slow biomass growth rate at $9^{\circ}C$ and low biomass retention in the reactor. Nevertheless, this study demonstrated the potential sulfate reduction rate of psychrotolerant sulfate-reducing mesophiles at suboptimal temperature.

• Journal of Auto-vehicle Safety Association
• /
• v.10 no.3
• /
• pp.45-54
• /
• 2018

Greenhouse gas is the big issue of the whole world. So foreign countries, EU, USA, Japan, China and Korea made the policy for reducing greenhouse gas. For calculation of reduction, it is necessary to know the quantity of current greenhouse emission per year in Korea. It is not reflected real driving condition for measuring the Fuel economy and greenhouse gas. The subject of this study is to figure out the characteristics which influence on greenhouse gas in real driving condition. And final goal is applying the policy greenhouse emission reduction.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.639-642
• /
• 2001

The possibility of weight reduction of rotor part in gas-gas geater(GGH) is studied from the viewpoint of allowable stress. In this work, finite element analysis(FEA) is performed with original model and three weight-reduced models with different diaphragm thickness, respectively. Stress concentrations at rotor diaphragm happen due to the dead weight, pressure difference between treated gas and untreated gas and thermal distribution in the rotor. As the thickness of diaphragm is decreased, the stress level is increased. The direction of treated gas and untreated gas flow may affect the stress level. Fatigue life assessment is not considered because pressure difference, the only cyclic load, can be ignored. The possible weight-reduced model is presented.

• Journal of the Korean Institute of Gas
• /
• v.14 no.4
• /
• pp.18-23
• /
• 2010

After conducting QRA(quantitative risk assessment) for the high pressure urban gas pipelines planned to be installed, RMMs(risk mitigation measures) when the societal risk is outside the acceptable region have been derived in this paper. Also risk reduction rates are calculated for each RMM. As a result of QRA, we find out that damaged distance caused by radiational heat is largely dependent upon the wind velocity and the atmospheric stability. The measure that has the highest risk reduction effect is No. 10 which includes pipeline corrosion monitoring, MOV(motor operated valve) installation and the method to protect pipeline damage caused by third-party mechanical interference, and which shows 75 % of risk reduction effect.

• Journal of Climate Change Research
• /
• v.7 no.3
• /
• pp.217-229
• /
• 2016

Increased evidences reveal that the global climate change adversely affect on the environment. Smart grid system is one of the ways to reduce greenhouse gas emissions in the electricity generation sector. Since 2013, Korea Electric Power Corporation (KEPCO) has installed smart grid station in KEPCO office buildings. The goal of this paper is two folds. One is to quantify the reduction in greenhouse gas emissions through smart grid stations installed in KEPCO office buildings as a part of pilot project. Among components of smart grid stations, this research focused on the photovoltaic power system (PV) and energy storage system (ESS). The other is to estimate the reduction in greenhouse gas emissions when PV is applied on individual houses. Results show that greenhouse gas emissions reduce 5.8~11.3% of the emissions generated through the electricity usage after PV is applied in KEPCO office buildings. The greenhouse gas emissions reduction from ESS is not apparent. When PV of 200~500 W is installed in individual houses, annual greenhouse gas emission reduction in 2016 is expected to be approximately $2.2{\sim}5.4million\;tCO_2-eq$, equivalent to 6~15% of greenhouse gas emissions through the electricity usage in the house hold sector. The saving of annual electricity cost in the individual house through PV of 200 W and 500 W is expected to be 47~179 thous and KRW and 123~451 thousand KRW, respectively. Results analyzed in this study show the environmental effect of the smart grid station. In addition, the results can be further used as guidance in implementing similar projects.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.1117-1121
• /
• 2008

Recently energy consumption and $CO_2$ emission issue are important problem on international society. The present study has been conducted economic analysis considering economical value of $CO_2$ reduction effect. We analyze annual energy cost and annual $CO_2$ emission of the cogeneration system and gas boiler system in hotel. The first results shows that annual energy cost of cogeneration system (751,740,126 won) is more profitable than gas boiler system (801,128,408 won) by 6.2% (49,388,281 won). The second results shows that annual $CO_2$ emission of cogeneration system (3,297 ton) is less than gas boiler system (3,536 ton) by 6.8% (239 ton). The Economical value of $CO_2$ reduction effect is 4,773,898 won. The cost effect according to the reduction of $CO_2$ is corresponding to 9.7% of reduction cost for total energy cost. The result of this study means that $CO_2$ reduction effect is essential item in introduction and change of facility for economic analysis.

• Journal of Environmental Impact Assessment
• /
• v.22 no.3
• /
• pp.195-201
• /
• 2013

Local governments are establishing their own greenhouse gas reduction goal and are playing a important role to respond to climatic changes. However, there are difficulties in quantitative analyses such as estimation of future greenhouse gas emission and computation of reduction potential, which are procedures required to establish mid to long term strategies to realize of low carbon society by each local governments. Also, reduction measures must reflect characteristics of each local government, since the reduction power of each local government can differ according to characteristics of each. In order to establish strategies that reflect characteristics of local governments, types of greenhouse gas emission from cities were classified largely into residential city, commercial city, residential commercial city, agriculture and fishery city, convergence city, and industrial city. As a result of analyzing basic unit of greenhouse gas emission by local government during 2007 in terms of per population, household and GRDP based on the type classification, significant results were deduced for each type. To manage the amount of the national greenhouse gas, reduction measures should be focused on the local governments that emits more than the average of each type's GHG emission.