• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.52 no.7
• /
• pp.335-342
• /
• 2003

This paper presents a forward type high voltage pulse power supply for high voltage small current, which can be designed as a simple circuit configuration and managed easily using Power-MOSFET in the view of commercialization. According to the switching frequency, coupling factor(k) and duty ratio(D), the Principle of basic operation and the characteristics of the proposed pulse power supply are estimated. Simulation results have demonstrated the feasibility of the proposed pulse power supply. Also experimental results are presented to verify theoretical discussion with a lamp type ozonizer as a load. For studying the application at the part of environment of water, When ozonizer gas reacts with a colon bacillus, the sterilization characteristics of a colon bacillus according to the ozone concentration and response time have been investigated. This proposed pulse power supply will be able to be practically used as a pulse power supply in various environment improvement facilities like sterilization of colon bacillus, deodorization, and Nox gas elimination.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.57 no.4
• /
• pp.73-84
• /
• 2015

An embankment raising project on 113 agricultural reservoirs in Korea was implemented in 2009 to increase water supply capacity for agricultural water and instream uses. This study evaluated the future water supply capacity of the Imgo reservoir at which the agricultural reservoir embankment raising project was completed, considering climate change scenarios. The height of the embankment of the reservoir was increased by 4.5 m, thereby increasing its total storage from 1,657.0 thousand to 3,179.5 thousand cubic meters. To simulate the reservoir water storage with respect to climate changes, two climate change scenarios, namely, RCP 4.5 and RCP 8.5 (in which greenhouse gas reduction policy was executed and not executed, respectively) were applied with bias correction for reflecting the climate characteristics of the target basin. The analysis result of the agricultural water supply capacity in the future, after the agricultural reservoir embankment raising project is implemented, revealed that the water supply reliability and the agricultural water supply increased, regardless of the climate change scenarios. By simulating the reservoir water storage considering the instream flow post completion of the embankment raising project, it was found that water shortage in the reservoir in the future is not likely to occur when it is supplied with an appropriate instream flow. The range of instream flow tends to decrease over time under RCP 8.5, in which the greenhouse gas reduction policy was not executed, and the restoration of reservoir storage was lower in this scenario than in RCP 4.5, in which greenhouse gas reduction policy was executed.

• 한국가스학회:학술대회논문집
• /
• 2000.09a
• /
• pp.137-142
• /
• 2000

• Journal of the Korean Institute of Gas
• /
• v.20 no.4
• /
• pp.1-6
• /
• 2016

A fuel supply system of heavy-duty CNG engine is composed as a module structure which is integrated by about 6 injectors. There are only one input and output passage for gas fuel supply in this injector module. The response performance for transient operation of an CNG engine is very poor because only one output fuel supply line is connected to the intake pipe after a throttle valve. In this study, a new guideline and internal flow design for the CNG injector module is suggested for the improvement of response performance by fluid dynamic simulations. As a result, the response performance of gas fuel supply can be improved by decreasing the total volume of internal flow passages and a same distance design from each injector to the exit of module shows good response performance and acquirement of linearity of fuel supply. But the injection order has little influence to injection performances.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.23 no.2
• /
• pp.95-103
• /
• 2019

Control systems of compressed gas supply facility are responsible for storing and supplying compressed gases required for launch complex qualification test and launch operation. Most of the facilities that make up the launch complex require compressed gas for their operation. Therefore, such control systems should be developed and verified earlier rather than the other systems that constitute the launch complex. Each verification for hardware and software is performed separately. In particular, software verification of control algorithms loaded on the controller takes a lot of time and man power during the development period of the control system. Thus, specific test procedures and methods should be prepared in advance for efficient development. This paper introduces the configuration of a compressed gas supply facility and its control system with the verification procedure and results of major algorithms.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.520-525
• /
• 2000

This research is to analyze the ventilation performance of mechanical ventilation systems for indoor air quality control and management. A ventilation performance with supply sites is evaluated in a test model chamber and office room. A $CO_2$ gas as a tracer gas is used to measure the ventilation performance. The ventilation performance is found to increase with increased the ventilation rate. The ventilation performance is analysed with 55% at the supply air of 570 lpm and with 20% at the supply air of 100 lpm in a test chamber. The ventilation performance is better than 15% comparing with natural decay at the supply of 570 lpm in office room.

• Transactions of the Korean hydrogen and new energy society
• /
• v.30 no.5
• /
• pp.473-477
• /
• 2019

In this paper, cold heat price contained in the 1 ton/h of LNG has been evaluated using PRO/II with PROVISION release 10.2 from Aveva company when LNG is used to liquefy several refrigerants instead of using vapor recompression refrigeration cycle. Normal butane, R134a, NH3, R22, propane and propylene refrigerants were selected for the modeling of refrigeration cycle. It was concluded that LNG cold heat price was inversely proportional to the refrigerant supply temperature, even though LNG supply flow rate is not varied according to the refrigerant supply temperature.

• Journal of the Korean Institute of Gas
• /
• v.24 no.5
• /
• pp.74-81
• /
• 2020

In general, when manufacturing a semiconductor, a number of hazardous and dangerous substances such as flammability, toxic, and corrosiveness are used. In particular, semiconductors are manufactured using specialty gas in processes such as CVD and etching. The specialty gas is filled in a container in the state of compressed or liquefied gas, and a gas cylinder cabinet is used as a facility for supplying this specialty gas to the semiconductor manufacturing process. When a accident occurs in the gas supply system, gas is released through a pressure release device installed in the gas cylinder to secure the safety of the supply system. In this case, the gas released inside the gas cabinet, there is a risk of leaking to the outside. After that, by analyzing the gas flow in the gas cabinet, it is intended to identify the risk associated with leak and to provide measures to prevent accidents.

• Journal of Energy Engineering
• /
• v.29 no.1
• /
• pp.13-24
• /
• 2020

Many countries are actively engaging in the reduction of greenhouse gas emissions, and as part of this effort, gradually reducing the portion of coal power generation and instead increasing the portion of power generations from renewable energy sources and natural gas. Korea is taking a similar policy to expand LNG power generation for the next decade. There is a concern, though, about the policy not being aligned with the domestic industry development, since only a few products are being made in Korea along the LNG power generation industry value chain. Therefore in this paper, we first looked at the current status of the gas turbine and high temperature parts industry used for LNG power generation in Korea, and then looked into the industrial issues and challenges through the analysis of supply chains of the domestic gas turbine industry. Finally, we tried to propose strategies to revitalize and localize the domestic gas turbine and high temperature parts industry. The proposed strategies can be summarized as 1) creation of domestic gas turbine manufacturing ecosystem via construction of gas turbine alliance, 2) strategic R&D support for localization of gas turbine and high temperature parts, and 3) provision of domestic testbeds for technology evaluation and commercialization.

• Journal of the Korean Institute of Gas
• /
• v.25 no.6
• /
• pp.1-6
• /
• 2021

In this study, we developed AMI terminals of 1 (reader): N (small transmitter). Currently, the government is focusing on the Gas AMI demonstration project to advance the outdated metering system of the urban gas industry, led by the government-sponsored ministries. The supply of gas AMI meters has the advantage of resolving uncertainties in privacy violations and measurement information and preparing for consumer safety through gas leakage detection. In the case of existing AMI meters, readers and transmitters were 1:1 methods, while this technology can be extended to multiple generations with a 1:N method, and a technology that can extend battery life by implementing a low-power design is applied. We hope that this research will contribute to the gas AMI supply project in the future.