• Journal of the Korean Solar Energy Society
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• v.23 no.4
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• pp.45-54
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• 2003

For cooling of double effect absorption heat pump system of solar heating source, analysis of thermodynamic design data has been done to find the property of Libr-water + ethylene Glycol mixture for working fluid by computer simulation. Derived thermodynamic design data, enthalpy based coefficient of performance and flow ratio for possible combinations of operating temperature for water - LiBr and Ethylene Glycol mixture ($H_2O$ : CHO ratio 10:1 by mole) by computer simulation are done. The obtained results, COP and mass flow ratio of the water - lithium bromide - ethylene glycol system, are compared with data for the water-Libr pair solution.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.375-379
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• 2016

Recently derived energy dissipation equation by Chamani(2008) and the profile function of the free overfall by Marchi(1993) were verified with present experiment data. The experiment was conducted in hydraulic laboratory, Hanyang University where the flume is 7m long and 0.44m wide, and the height of the drop structure is 0.205m. Water depth and free overfall profile data were collected using an ultra sonic distance sensor and photographic images. The time-averaged water depth data and the free overfall profile were analyzed to examine the energy dissipation pattern over the drop structure

• International Journal of Naval Architecture and Ocean Engineering
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• v.13 no.1
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• pp.178-186
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• 2021

The wave power extraction by multiple Wave Energy Converters (WECs) deployed in a Y-shaped Water Channel Resonator (WCR) has been investigated. A WCR consists of a long water channel, and a V-shaped wave guider installed at the entrance of a water channel. If the period of the incident waves coincides with the natural periods of the fluid in a WCR, resonance occurs, as a result, the internal fluid in a WCR is greatly amplified. To estimate the wave power by multiple WECs placed at the antinodal points in a WCR, the heave motion response, time-averaged power, and capture width ratio were calculated for several design parameters. Also, the systematic model tests were conducted in a 2D wave tank. The numerical results are in good agreement with the experimental data. It was verified that a WCR helps the WECs to produce electricity more effectively by amplifying the wave energy in a WCR.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.20 no.2
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• pp.185-192
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• 2022

A compacted bentonite buffer is a major component of engineered barrier systems, which are designed for the disposal of high-level radioactive waste. In most countries, the target temperature required to maintain safe functioning is below 100℃. If the target temperature of the compacted bentonite buffer can be increased above 100℃, the disposal area can be dramatically reduced. To increase the target temperature of the buffer, it is necessary to investigate its properties at temperatures above 100℃. Although some studies have investigated thermal-hydraulic properties above 100℃, few have evaluated the water suction of compacted bentonite. This study addresses that knowledge gap by evaluating the water suction variation for compacted Korean bentonite in the 25-150℃ range, with initial saturations of 0 and 0.22 under constant saturation conditions. We found that water suction decreased by 5-20% for a temperature increase of 100-150℃.

• Solar Energy
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• v.19 no.3
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• pp.13-21
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• 1999

Calculation method about the water temperature variable inside hot water pipe had proposed in the past does not correspond with branch pipe system, variable of water volume, variable of entrance water temperature, using and so on. A calculation method proposed in this paper can solve above problems, and calculate the kinds variation of the water temperature inside pipe in the real use state of the hot water pipe.

• Advances in environmental research
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• v.6 no.3
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• pp.203-216
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• 2017

For survival of human beings clean water is an essential commodity whereas contamination in drinking water threatens to mankind. The main cause of water contamination is social and development activities of human being along with increasing population. The community in the study area has acute shortage of drinking water along with about 40 to 60% has no access to safe drinking water. This study indicates drinking water quality of two major sources of coastal belt of Karachi one is supplied by Karachi Water & Sewerage Board (KWSB) as tap water and the other through groundwater. The physicochemical analysis was carried out by following the standard methods for checking the quality of drinking water. The analyzed results showed that the quality of groundwater was unfit as potable water. The most critical situation was observed as high level of contamination followed by high turbidity and increased salinity levels. TDS in surface water were found 12% above and TDS in groundwater was 20% below the National Drinking Water Quality Standards (NDWQS) of Pakistan as well as the permissible WHO drinking water quality guidelines.

• Corrosion Science and Technology
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• v.21 no.5
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• pp.327-339
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• 2022

The water-jet technique started by Bridgman can cut metal and alloys without harmful gas and fume. However, while this technique is convenient to cut metals and alloys, in the case of coated pipe, water jet induces the degradation of coatings on the pipes, and may facilitate structural failure, leakage, and loss of products. While there are many reports on the effect of water jet on cut metals and the damage of metallic materials, research on the effect of water impingement on the epoxy coatings has been little studied. In this work, we therefore control the velocity of water jet, distance between nozzle and specimen, and water temperature, and discuss the effect of water impingement on the epoxy coatings. Increasing water velocity and water temperature and reducing nozzle distance increased the degradation rates of three epoxy coatings were increased. Among three test parameters - water velocity, nozzle distance and water temperature, water temperature was relatively effective to increase the degradation rate of epoxy coatings.

• Water for future
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• v.28 no.1
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• pp.145-152
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• 1995

This paper presents an experimental study on the Cherepnov water lifter that can pump or lift water without the use of external energy such as electricity. The energy used by the lifter is derived from the potential energy of the water itself. The liffter consists of three interconnected tanks, one of which is open and two others are hermetically sealed. The water level and the pressure in each tank were measured to improve the undestanding of the behavior and the operational charateristics of the lifter. The effects of varying operating parameters such as the inflow rate, tank and pipe sizes, the relative positions of the tanks were analyzed. As a results, factors that can maximize the efficiency, shorten the cycle time and increase the delivery rate were identified.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.281-285
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• 2009

This paper is to simulate a solar hot water heating system used in a medium-scale office building using the dynamic simulation. This study is focused chiefly on the annual variation of energy performance, the solar fraction with respect to the difference of hot water load temperature. For this purpose the simple model of a solar hot water heating system has been considered with TRNSYS program and the simulations were performed with the weather data in Seoul, Korea. The share ratio of solar hot water system of the summer season appeared higher than the winter season because that the decrease of the domestic hot water load was far despite the relative decrease of the solar radiation. As the temperature was lower from $60^{\circ}C$ to $50^{\circ}C$, the solar fraction increases 8.1 percent due to 20-percent decrease of annual hot water load.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.171-178
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• 2006

In advanced countries, state-of-the-art temperature monitoring technique is widely used for effective use of geothermal resources. But these kind of modern tools such as Thermal Line Sensor has not been applied to find geothermal characteristics of alluvium and riverbed in domestic area. In this research, state-of-the-art thermal line temperature sensor monitoring was introduced. And long term field test using this type of sensor was performed to find geothermal characteristics of alluvium and riverbed and evaluate the availability for heat energy source. As a result, temperature monitoring technique through thermal line sensor was very effective to obtain basic geothermal information of alluvium deposit and riverbed. Also, it was found that the groundwater temperature phase showed its potential of utilization as a energy source of heat pump. It is estimated that further study shows a specific corelation between temperature monitoring data and its availability as a energy source.