• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.113-120
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• 2013

Miscanthus is one of the promising energy crops for producing bioethanol or bioenergy in many countries. A field of about 180 ha for miscanthus plantation was started for demonstration near Geum River in 2011. Since the size of the field is much larger than those of traditional cultivation for one single crop in this country, questions were raised if there are any environmental impacts from the energy crop plantation, particularly on water quality. In this study, water quality of runoff water from three different plots was analyzed for assessing the impacts of energy crop production. The results showed that there were no substantial differences among the plots; control, the first, and the second year growth fields. The concentrations of COD, T-N, and T-P were lower than those in runoff water from agricultural crop fields. The second year field showed a slight higher values of COD and T-N concentrations due to the biodegradation of residue of miscanthus which was not cultivated for observation. Commercial planation of miscanthus in a large scale would not result in a water quality problem when avoiding application of fertilizer as practiced in agricultural crop fields.

• Advances in environmental research
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• v.2 no.2
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• pp.119-129
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• 2013

The study examined the effect of urbanization on the water quality of Nwaorie and Otamiri Rivers in Owerri metropolis, Imo State, South-East Nigeria. Water samples were collected from Nwaorie and Otamiri Rivers from four sampling stations up and down stream. Water parameters analyzed using standard procedures were: color, turbidity, temperature, pH, total hardness, total solids, metals (Iron and magnesium), anions (nitrate and ammonia) and Fecal coliform. Results showed increased levels of coloration, iron, ammonia, turbidity and fecal coliform which exceeded the World Health Organization (WHO) permissible limits for drinking water. Increase in these parameters indicated influx of industrial effluent from the nearby industries and indiscriminate disposal of wastes at the bank of the rivers. Application of ANOVA showed various degree of variation in pollutants levels between the two rivers and at different sampling points. River Nwaorie was observed to be more impacted than River Otamiri. High values of iron observed from the study could be deleterious to human health if the river water is consumed without treatment. The study, therefore, recommended proper waste management and disposal as well as effluent treatments in Owerri municipal against pollution of surface water.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.163-163
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• 2019

The rapidly growing global population increases the awareness of water, energy, and food security worldwide. The concept of Water, Energy, and Food nexus (hereafter, WEF nexus) has been widely introduced as a new resources management concept that integrate the water, energy, and food in a single management framework. Recently, WEF nexus analyzes not only the interconnections among the resources, but also considers the external factors (such as environment, climate change, policy, finance, etc) to enhance the resources sustainability by proper understanding of their relations. A nation-level resources management is quite complex task since multiple regions (e.g., watersheds, cities, and counties) with different characteristics are spatially interconnected and transfer the resources each other. This study proposes a multiple region WEF nexus simulation and transfer model. The model is equipped with three simulation modules, such as local nexus simulation module, regional resources transfer module, and optimal investment planning module. The model intends to determine an optimal capital investment plan (CIP), such as build-up of power plants, water/waste water treatment plants, farmland development and to determine W-E-F import/export decisions among areas. The objective is to maximize overall resources sustainability while minimize financial cost. For demonstration, the proposed model is applied to a semi-hypothetical study area with three different characterized cities. It is expected the model can be used as a decision support tool for a long-term resources management planning process.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.737-745
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• 1996

In recent years, with the increase in the consumption of natural resources and energy, global environmental problems have appeared. This is a very serious environmental load on worldwide food production. For this reason, innovative techniques for production of low entropy by using effectively the energy for the ecosystemic agriculture have been expected. In this study, granular ceramics of 2 to 3mm in diameter having electrical charges at the surface were produced, using the natural raw materials of silicate minerals haing excellent moldabilities and sintering properties . Production of water having functions was attempted by effective use of the electrochemical energy of the ceramics with an efficient water treatment apparatus in which the ceramics were fluidized in water, differently from conventional systems. In the experimental results, the EC of water treated with the ceramics was not changed, but the ORP and also the pH and the DO were changed. The speed of oxidation -re uction reaction was high, and the ceramics -treated water enhanced the vigor of seeds. It can be expected that this treatment system, by which the ORP of water can be moderately controlled, is advantageous in controlling the growth of plants.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.544-549
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• 2009

The purpose of this study is to investigate the field Operation Characteristics of a sea water heat source cascade heat pump system and system applicable to Building. Cascade heat pump system is composed R410A compressor, R134a compressor, EEV, cascade heat exchanger, Plate heat exchanger etc. Building area is $890m^2$ and has five floors above ground. R410A is used for a low-stage working fluid while R134a is for a high-stage. The system could runs at dual mode. One is mode of general R410A refrigeration cycle in summer and the other is cascade cycle. In order to gain a high temperature supply water in winter season, the system is designed to perform a cascade cycle. The filed test results show that the sea water heat source heat pump system exhibits a COP of about 5.5 in cooling mode along with a heating COP of about 4.0 in 1-stage heating mode. Cascade 2-stage heat pump system is enough to supply $60^{\circ}C$ water and heating COP is about 3.0

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.623-625
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• 2015

Recently, the cooling water of power plant was included in RPS(Renewable Portpolio Standard) as water heat energy. Thus the trend of cooling water application is growing bigger for agriculture and fishing industry. Especially as energy consumption cost in agriculture and fishing industry is a vital element, the interests for energy efficiency is growing bigger. The advanced agriculture country like Netherlands is distributing diagnosis software to the farmers based on ICT diagnostic system for the efficient energy consumption and energy demand amounts depend on crops of cultivation in automated horticulture. Hereafter, in the preparation of the expansion of the automated agriculture domestically by the cooling water of power plant, we would like to propose the energy application case(Greenery) in the advanced countries abroad in agriculture and EMS system about the application of the cooling water in power plant.

• Particle and aerosol research
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• v.13 no.2
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• pp.65-77
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• 2017

In recent large-scale semiconductor manufacturing cleanrooms, the energy consumption in outdoor air conditioning (OAC) systems to heat, humidify, cool and dehumidify outdoor air(OA) represents about 40~50 % of the total cleanroom power consumption required to maintain cleanroom environment. Therefore, the assessment of energy consumption in outdoor air conditioning systems is essential for reducing the outdoor air conditioning load for a cleanroom. In the present study, an experiment with an outdoor air flow rate of $1,000m^3/h$ was conducted to compare the energy consumption in steam humidification, simple air washer, exhaust air heat recovery type air washer and dry cooling coil(DCC) return water heat recovery type air washer OAC systems. Besides, a numerical analysis was carried out to evaluate the annual energy consumption of the aforementioned four OAC systems. It was shown that the simple air washer, exhaust air heat recovery type air washer and DCC return water heat recovery type air washer OAC systems using water spray humidification were more energy-efficient than the steam humidification OAC system. Furthermore the DCC return water heat recovery type air washer OAC system was the most energy-efficient.

• Membrane Journal
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• v.32 no.6
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• pp.475-485
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• 2022

The continuous excessive consumption of fossil fuels is causing global warming, climate, and environmental crisis. Accordingly, hydrogen energy attracts attention among alternative energies of fossil fuels, because it has the advantage of not emitting pollutants and not having resource restrictions. Therefore, various studies are being conducted on a water electrolysis system for producing hydrogen and a fuel cell system for producing electricity by using hydrogen energy as a fuel. In this study, 3D ionomer models were produced by reflecting the excessive water condition of an anion-conductive ionomer material, which is one of the core materials of water electrolysis systems and fuel cells. Finally, by analyzing the structural stability and performance of the ionomer under an excessively hydrated condition, we suggested a performance improvement factor in the design of an anion conductive ionomer, a key material for water electrolysis systems and fuel cells.

• Journal of the Korean Electrochemical Society
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• v.26 no.4
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• pp.56-63
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• 2023

The development of renewable energy technologies, such as solar, wave, and wind power, has led to the diversification of water electrolysis technologies, which can be easily coupled with renewable energy sources in terms of economics and scale. Water electrolysis technologies can be classified into three types based on operating temperature: low-temperature (<100 ℃), medium-temperature (300-700 ℃), and high-temperature (>700 ℃). It can also be classified by the type of electrolyte membrane used in the system. However, the concepts of thermodynamic and thermo-neutral voltages calculations and are very important factors in the evaluation of energy consumption and efficiency of water electrolysis technologies, are often confused. This review aims to contribute to a better understanding of the calculation of operating voltage and efficiency of PEM water electrolysis technologies and to clarify the differences between thermodynamic voltage and thermo-neutral voltage.

• Journal of Electrochemical Science and Technology
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• v.12 no.3
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• pp.302-307
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• 2021

Polymer electrolyte membrane (PEM) electrolyzer or alkaline electrolyzer is required to produce green hydrogen using renewable energy such as wind and/or solar power. PEM and alkaline electrolyzer differ in many ways, instantly basic materials, system configuration, and operation characteristics are different. Building an optimal water hydrolysis system by closely grasping the characteristics of each type of electrolyzer is of great help in building a safe hydrogen ecosystem as well as the efficiency of green hydrogen production. In this study, the basic operation characteristics of a kW class alkaline water electrolyzer we developed, and water electrolysis efficiency are described. Finally, a brief overview of the characteristics of PEM and alkaline electrolyzer for large-capacity green hydrogen production system will be outlined.