• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.74-79
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• 2011

This study was accomplished to evaluate the performance of Multi Effect Distillation(MED) for solar thermal desalination system. It was designed Multi effect distillation with $3m^3/day$ capacity and Shell&Tube type heat exchanger. Also, The effective heat transfer of Shell&Tube heat exchanger was used Cu(90%)-Ni(10%) corrugated tube. The parameters relating to the performance of Multi Effect Distillation are known as hot water flow rate. The experimental conditions for each parameters were $18^{\circ}C$ for sea water inlet temperature, $6m^3/hour$ sea water inlet volume flow rate, $75^{\circ}C$ for hot water inlet temperature, 2.4, 3.6, and $4.8m^3/hour$ for hot water inlet volume flow rate, respectively. The results are as follows, Development for Multi effect distillation was required about 40kW heat and 35kW cooling source to produce $3m^3/day$ of fresh water. And, Performance ratio of Development Multi effect distillation was about 2.0191.

• Nuclear Engineering and Technology
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• v.52 no.1
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• pp.27-36
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• 2020

Natural convection and thermal stratification phenomena are found in large water pools that are being used as heat sinks for decay heat removal from the reactor core using passive heat removal systems. In this study, the two-phase (water and air) natural convection and thermal stratification phenomena with conjugate heat transfer in the rectangular enclosure were investigated numerically using ANSYS Fluent 17.2 code. The transient numerical simulations of these phenomena in the full-scale computational domain of the experimental facility were performed. Generation of water vapour bubbles around the heater rod and evaporation phenomena were included in this numerical investigation. The results of numerical simulations are in good agreement with experimental measurements. This shows that the natural convection is formed in region above the heater rod and the water is thermally stratified in the region below the heater rod. The heat from higher region and from the heater rod is transferred to the lower region via conduction. The thermal stratification disappears and the water becomes well mixed, only after the water temperature reaches the saturation temperature and boiling starts. The developed modelling approach and obtained results provide guidelines for numerical investigations of thermal-hydraulic processes in the water pools for passive residual heat removal systems or spent nuclear fuel pools considering the concreate walls of the pool and main room above the pool.

• Journal of Electrochemical Science and Technology
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• v.10 no.2
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• pp.104-114
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• 2019

Energy is an essential driving force for modern society. In particular, electricity has become the standard source of power for almost every aspect of life. Electric power runs lights, televisions, cell phones, laptops, etc. However, it has become apparent that the current methods of producing this most valuable commodity combustion of fossil fuels are of limited supply and has become detrimental for the Earth's environment. It is also self-evident, given the fact that these resources are non-renewable, that these sources of energy will eventually run out. One of the most promising alternatives to the burning of fossil fuel in the production of electric power is the proton exchange membrane (PEM) fuel cell. The PEM fuel cell is environmentally friendly and achieves much higher efficiencies than a combustion engine. Water management is an important issue of PEM fuel cell operation. Water is the product of the electrochemical reactions inside fuel cell. If liquid water accumulation becomes excessive in a fuel cell, water columns will clog the gas flow channel. This condition is referred to as flooding. A number of researchers have examined the water removal methods in order to improve the performance. In this paper, a new water removal method that investigates the use of vibro-acoustic methods is presented. Piezo-actuators are devices to generate the flexural wave and are attached at end of a cathode bipolar plate. The "flexural wave" is used to impart energy to resting droplets and thus cause movement of the droplets in the direction of the traveling wave.

• Membrane Journal
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• v.30 no.6
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• pp.359-372
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• 2020

Compared to other oil/water separation methods, oil/water separation membranes have low energy costs and higher performance levels. Superhydrophilicity and underwater superoleophobicity are factors that are most vital in developing effective oil/water separation membrane. In addition, antifouling property and biodegradability are also factors that have to be considered in developing the membranes. In this review, studies which have enhanced the oil/water separation efficiency by modifying the chemistry and morphology of the surface of the membrane are discussed.

• Analytical Science and Technology
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• v.21 no.4
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• pp.279-283
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• 2008

Blood soil and the mixture of blood soil, elvan soil and, silica soil materials were molded, then they were sintered in $1100^{\circ}C$ and were used for the emission of the far infrared ray boll. The emission from the manufactured bolls was relatively high in the range of $8{\sim}12{\mu}m$ wavelength each. The elution of minerals from mixture bolls was very low, but the elimination of heavy metal cadmium ion in activated water and energy water treated with mixture bolls was very high. Activated water and energy water had a high to the UV protected ability in comparison to drinking water.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.823-828
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• 2011

Characteristics of water separation in a FWKO(Free Water Knok Out) vessel was investigated to remove water from oil-water mixture. Decane, toluene, and asphalt were used as model oils. Preliminary experiments were carried out for decane in a prototype FWKO vessel. Based on the results of preliminary experiments, the prototype vessel was modified and its performance was evaluated by using toluene. The effects of experimental variables on the separation of oil-water mixture were evaluated in terms of separation efficiency. The experimental variables include water cut(water ratio), number of baffles, residence times, and operation temperatures. The optimum conditions of water separation were found to be 0.8 water cut, 3 baffles, 1,200 sec, and $45^{\circ}C$.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2019.05a
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• pp.325-326
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• 2019

• Journal of Animal Environmental Science
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• v.9 no.2
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• pp.69-78
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• 2003

In this study, the energy conversion equipment from the radiation energy to mechanical energy by using n­pentane as the operating fluid was constructed and the performance to pump the water was tested for the utilization of solar powered water pump. The equipment was designed optimally, after the theoretical analyses of the water pumping head and water quantity per cycle were done. The pentane vapour temperature in the condenser and the temperature of the outlet water from the condenser became lowered and the heat transfer rate became higher with decreasing the water inlet level to the condenser. The temperature difference between the condenser and the water tank was significant. Therefore, the distance between the water tank and condenser was recommended to be shorten and the diameter of their connecting pipe was recommended to be narrow in order to reduce the resistance of the fluid passage and improve the heat transfer rate. The amount of water pumped was 1.6­2.4 liters. Mass flow rate of the cooling water became lowered when the cooling water pipe was prolonged from the condenser to improve the heat transfer rate.

• Korean Chemical Engineering Research
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• v.56 no.2
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• pp.204-211
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• 2018

In this study, densities of water + N-Methyldiethanolamine (MDEA), Water + 2-Amino-2-Methyl-1-Propanol (AMP), MDEA + AMP binary systems and Water+MDEA+AMP ternary system were measured over the full range of composition at temperatures from 303.15 K to 333.15 K by using an Anton Paar digital vibrating tube densimeter (DMA4500). The experimental excess volumes have been obtained from the experimental density results and have been fitted using the Redlich-Kister-Muggianu expression. The parameters obtained from the binary excess volume data were used for the correlation of ternary system with one additional ternary parameter for each isotherm. All investigated binary and ternary systems are completely miscible, because the values of excess volume are negative under the examined conditions.

• Journal of the Korean Solar Energy Society
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• v.32 no.spc3
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• pp.213-219
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• 2012

Nanofluids are advanced concept fluid that solid particles of nanometer size are stably dispersed in fluid likes water, ethylene glycol and others. They have higher thermal conductivities than base fluids. If using this characteristic, efficiencies of heat exchangers can be increased. Therefore in this study, we measured thermal conductivity and viscosity of carbon nanofluids. They were made to ultra sonic dispersed oxidized multi-walled carbon nanotubes(OMWCNTs) in distilled water and ethanol, respectively. The mixture ratios of OMWCNTs were from 0.0005 vol% ~ 0.1 vol%. Thermal conductivity and viscosity was measured by transient hot-wire method and rotational viscometer. The results of an experiment are as in the following: thermal conductivity of the 0.1 vol% pure-water nanofluid improved 7.98% ($10^{\circ}C$), 8.34% ($25^{\circ}C$), and 9.14% ($70^{\circ}C$), and its viscosity increased by 37.08% ($10^{\circ}C$), 33.96% ($25^{\circ}C$) and 21.64% ($70^{\circ}C$) than the base fluids. Thermal conductivity of the 0.1 vol% ethanol nanofluids improved 33.72% ($10^{\circ}C$), 33.14% ($25^{\circ}C$), and 32.25% ($70^{\circ}C$), and its viscosity increased by 35.12% ($10^{\circ}C$), 32.01% ($25^{\circ}C$) and 19.12% ($70^{\circ}C$) than the base fluids.