• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.689-697
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• 2020

Hazardous and noxious substances (HNS) may cause maritime incidents during marine transportation, which are liable to lead to a large amount of spillage or discharge into the sea. The damage to the marine environment caused by the HNS spill or discharge is known to be much greater than the damage caused by oil spill. Particularly dangerous is HNS, which is deposited or buried in the seabed, as it can damage the organisms that live on, in, and near the bottom of the sea, the so-called "benthos," forming the benthic ecosystem. Therefore, it is vital that the HNS deposited on the seabed be recovered. In order to do so, procedures and equipment are required for accurate detection, stabilization treatment, and recovery of HNS in subsea sediment. Thus, when developing a mechanical recovery system, the performance requirements should be selected using performance indices, and the conceptual design of the mechanical recovery system should be based on performance requirements decided upon and selected in advance. Therefore, this study was conducted to arrive at a conceptual design for a mechanical recovery system for the recovery of HNS deposited on the seabed. In the design of the system, based on the fundamental scenario, the method of suction foundation with the function of self enclosing was adopted for recovering the HNS sediment in the subsea sediment. The mechanical recovery system comprises the suction foundation, pollution prevention, a pump system, control system, monitoring device, location information device, transfer device, and tanks. This conceptual design is expected to be reflected and used in the basic design of the components and shapes of the mechanical recovery system.

• Journal of Power System Engineering
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• v.18 no.1
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• pp.38-44
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• 2014

The objectives of this study are to measure the ball recovery rate of cleaning apparatus for plate heat exchanger. Ceramic ball is used for plate heat exchanger cleaning. The main components of cleaning apparatus are comprised of ball collector, ball trap, ejector, pump and plate heat exchanger. The ball recovery rate are obtained with change in recovery time and velocity of water. The results show that the ball recovery rate is slightly increased with increase in the recovery time and the velocity of water over 0.4 m/s in the straight flow. In the case of reverse flow, the ball recovery rate more increased than straight flow. The maximum ball recovery rate of the straight flow and reverse flow reach 83.97% and 86.61%, respectively, when the velocity and cleaning time are 0.5 m/s and 15min.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.3
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• pp.224-229
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• 2012

The importance of ventilation system is being emphasized by interest of indoor air quality. Especially, heat recovery ventilation system has attracted attention as most effective ventilation plan. Because it can reduce hazardous construction materials, indoor air pollutions, and also can reduce air conditioning energy cost. In heat recovery ventilator, the element core is the most important part. The element core is composed of liner and spacer. And liner and spacer are stacked alternately. On the Liner, heat and humidity transfer are made between supply and exhaust air. And spacer plays a role as a tunnel of exhaust and supply. In this study, we investigated and analyzed the efficiency of a heat recovery ventilator, when the spacer's properties are changed. As a result, difference spacer's properties affect an efficiency of heat recovery ventilator.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.3
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• pp.302-307
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• 2017

An electric steam boiler equipped with a condensate recovery system, which stores the condensate generated after using steam in steam washers, steam cookers, steam irons, and steam cleaners in a condensate tank and supplies compressed air to the condensate tank so that the condensate is recovered to the boiler by the pressure of the compressed air, was studied. In the results of this study, the heat energy balance between the quantity of the heat generated by the non-metallic surface heating element and the quantity of the heat absorbed by the water was good in a range of ${\pm}5%$. In addition, the heat transfer rate increased in proportion to the electric power of the surface heating element heater, the waste heat energy was normally recovered by the recovery of the condensate of the steam boiler equipped with the high compression waste heat recovery system, and the recovery rate of the waste heat exhibited 23%.

• New & Renewable Energy
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• v.18 no.2
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• pp.82-89
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• 2022

In this study, the exergy characteristics were analyzed, according to the mass flow rate of the propane working fluid and the pressure change in the turbine inlet, for the efficient recovery of cold energy and exhaust heat by the waste energy recovery system applied to the LNG FSRU regasification process. When the turbine inlet pressure and mass flow rate of the Primary Rankine Cycle were kept constant, the exergy efficiency and the net power increased. This occurred as the turbine inlet pressure and the mass flow rate of the working fluid increased in the Secondary Rankine Cycle, respectively, and the maximum values were confirmed. In this regard, the fluctuations in the exergy rate flowing into and out of the system and the exergy rate destroyed by pumps, evaporators, turbines, and LNG heat exchangers (condensers) were examined in detail.

• Journal of Energy Engineering
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• v.14 no.4 s.44
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• pp.248-258
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• 2005

In the present study, in order to estimate possibility as a waste heat recovery system, three different heat exchangers are developed. The developed heat exchangers are tile system to supply the hot water using fermentation of waste biomass. For the experiments, various biomass materials were examined to obtain the best heat recovery. Waste heat recovery system was studied numerically and experimentally. Heat exchanger system was designed specially to obtain the optimum heat exchanging performance. The biomass heat exchanger was operated for 20 minutes, after 1 hour from start-up, the temperature of the biomass dump has been raised to the possible operation temperature. From the three time operations per day, the system would be able to supply the amount of energy, about 62,400 kcal/day.

• Journal of Energy Engineering
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• v.18 no.1
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• pp.17-21
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• 2009

By using the heat recovery of water-cooled chillers, it is possible to reduce the energy operating costs positively and at the same time it could fulfill the heating re-heat air conditioning system as well as the hot water requirements. Basically templifiers are designed to economically to turn the waste heat into useful heat. Waste heat is extracted from a fluid stream by cooling it in the evaporator, the compressor amplifies the temperature of the heat and the condenser delivers the heat to heating loads such as space heating, kitchens and domestic hot water. Design of higher water temperature requirements and split condenser heat recovery chiller system (using of templifiers) produced hotter condenser water approximately up to $60^{\circ}C$ and control the entire heat recovery system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.9
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• pp.743-749
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• 2015

The purpose of this study is to predict the performance of an indirect evaporative cooling system, and to evaluate its energy saving effect when applied to the exhaust heat recovery system of an air-handling unit. We derive the performance correlation of the indirect evaporative cooling system using a plastic heat exchanger based on experimental data obtained in various conditions. We predict the variations in the performance of the system for various return and outdoor air conditioning systems using the obtained correlation. We also analyze the energy saving of the system realized by the exhaust heat recovery using the typical meteorological data for several cities in Korea. The average utilization rate of the sensible cooling system for the exhaust heat recovery is 44.3% during summer, while that of the evaporative cooling system is 96.7%. The energy saving of the evaporative cooling system is much higher compared to the sensible cooling system, and was about 3.89 times the value obtained in Seoul.

• Journal of Power System Engineering
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• v.16 no.3
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• pp.5-9
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• 2012

Novel mechanisms for Energy Recovery Devices are proposed to diminish the pressure loss in the high-pressure reverse-osmosis system. In the beginning, the state-of-the-art in the design of Energy Recovery Devices is reviewed and the features of each model are investigated. The direct-coupled axial piston pump(APP) and axial piston motor(APM) showed 39% energy recovery at operating pressure of reverse osmosis desalination systems, 60 bar. Meanwhile, the developed PM2D model, in which APM pistons are arranged parallel to those of APP, is more compact and showed higher efficiency in a preliminary test. Loss-reduction mechanisms employing rod piston and double raw valve port are additionally proposed to enhance the efficiency and durability of the device.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.6
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• pp.53-60
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• 2011

The effect of exhaust heat recovery system can be evaluated by two well known method. First method is to measure the time duration from engine start under cold coolant temperature till coolant get warmed. By this methodology coolant warming duration can be index of warm-up effect. Second method is to analyze heat balance of the engine during warm-up phase under steady engine operation so that wasted energy by losses such as cooling and exhaust can be index of warm-up effect. This study focused on evaluation of warming-up effect by both methodology above mentioned using 2L SI engine under from idle to 2000rpm steady condition. Results, idle operation showed low heat recovery efficiency but under higher engine speed condition, remarkable heat recovery efficiency improvement was observed. In 2000rpm steady condition, warm-up duration of engine is decreased by exhaust heat recovery system.