• 한국지열·수열에너지학회논문집
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• 제15권4호
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• pp.39-45
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• 2019

The operational conditions such as cooling tower water pump flow rate, cooling tower fan flow rate, and chiller capacity in heat source equipment, and supply air temperature and chilled water temperature in air conditioner are considered to study the effects on energy consumption for central cooling system by using TRNSYS program. As a result, the optimal values of supply air temperature and chilled water temperature for minimal total energy consumption are 12℃ and 8℃. And if maximum values of cooling tower water pump and fan flow rate is decreased from 100% to 40%, energy consumptions are increased 170MJ/day and 63.2MJ/day, respectively.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.313-316
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• 2006

As Decentralized Generation(DG) becomes more reliable and economically feasible, it is expected that a higher application of DG units would be interconnected to the existing grids. This new market penetration of DG technologies is linked to a large number of factors like technologies costs and performances, interconnection issues, safety, market regulations, environmental issues or grid connection constrains. Korea Electric Power Corporation (KEPCO) has researched performance characteristics of the 60k W class 1) basic start-up & shutdown operation analysis 2) interconnection test 3) MGT -absorption chiller-heater system in the local condition. Variations of heat recovery from exhaust gas has measured according to micro gas turbine output of 15, 30, 45, 60kW. From those results, the performance of the MGT-absorption chiller/heater system has been evaluated. The suggested strategy and experience for the evaluation of the distributed generation will be used for the introduction of other distributed generation technologies into the grid in the future.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.1119-1124
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• 2006

The objectives of this paper are to investigate the performance of silica gel-water adsorption refrigeration system with heat recovery process from the system experiment. This system can be driven by waste heat at near ambient temperature from $60^{\circ}C$ to $90^{\circ}C$. The cooling capacity and coefficient of performance(COP) were measured from various experimental conditions. An experimental results revealed the influence of operating temperatures(hot, cooling and chilled water), water flow rates, and adsorption-desorption cycle times on cooling capacity and COP. Under the standard conditions of $80^{\circ}C$ hot water, $25^{\circ}C$ cooling water, $14^{\circ}C$ chilled water inlet temperatures and 420sec cycle time, a cooling capacity of 1.14kW and a COP for cooling of 0.55 can be achieved.

• 한국지열·수열에너지학회논문집
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• 제16권4호
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• pp.1-8
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• 2020

For a central cooling system of a medical facility composed of absorption chiller and screw chiller, the study was conducted on how to minimize the energy cost. In consideration of the energy cost, the optimal operation method in which the operation method of the heat source is changed according to the size of the cooling load was derived through simulation analysis. When applying the optimal operation method, the indoor environment, energy consumption, and energy cost were analyzed and compared with the reference operation method.

• 한국태양에너지학회 논문집
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• 제25권2호
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• pp.63-69
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• 2005

This study is the survey of a transition procedure of building services systems(heat source, HVAC, water supply) through the survey of existing office buildings, building design documents. The preference & major consideration of system selection is the engineer's opinions. The results of this survey can be used in selection of building services system design. In this survey, "Hot & cold water generator system" and "single duct CAV+FCU system", "Elevated water tank system" are selected. The most important consideration in system selection is the energy saving in heat source system, and comfort in HVAC system, and water pressure in water supply system. They prefer "steam boiler+absorption chiller system" for heat source system, "steam boiler+ice thermal storage system", "hot & cold water generator system", "district heating+absorption chiller system" : "single duct CAV+FCU system" and "single duct VAV+convector system" for HVAC system: and "booster pump system" for water supply system.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2007년도 춘계학술대회
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• pp.230-233
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• 2007

A system of anodic process of aluminum thin film has implemented for nanofabrication. The manufactured equipment consists of three main parts: chiller, reaction bath and power supply. The chiller module consists of refrigeration compressor, copper tube and coolant with a thermostat. The reaction bath has kept in same temperature as a thermodynamic canonical ensemble system during the anodic reaction process. The magnetic bar has stirred oxalic acid in bath for uniform reaction. The DC power supply has applied into two electrodes, aluminum for anode and platinum for cathode in the oxalic acid. The anodization process results in the formation of nanoporous thin films.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1034-1039
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• 2000

In turbo-machines operated at high speeds through gear speed increasers a precise coupled analysis of lateral and torsional vibrations is required to achieve highly reliable designs with low vibration and low noise levels, where the vibration coupling is due to the gear pair mesh stiffness. In this paper, applying the generalized coupled lateral-torsional finite element model of a gear pair element, has been analyzed a coupled lateral-torsional vibration of the prototype 800 RT turbo-chiller rotor-bearing system with a bull-pinion gear speed increaser. Results have shown that the coupled torsional natural frequencies have decreased due to the coupling effect of lateral vibration and particularly, the 2nd torsional natural frequency and its mode shape have had big changes. However, changes of lateral vibration characteristics have been noticed only at high lateral whirl natural frequencies above 15,000 rpm.

• 대한설비공학회지:설비저널
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• 제33권3호
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• pp.43-49
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• 2004

This article reviews R＆D of triple effect cycle developed in Japan. Most of the refrigeration and heat pump technologies are dominated by vapor compressor system. The vapor compressor system, however, is highly concerned with the environmental regulations , as most of the vapor compressor technologies are using CFCs or HCFCs which are known as ozone depleting and global warming gases. As a consequence, refrigeration technologists are trying to invent or to develop an alternative to vapor compressor refrigeration devices. Thermally driven, absorption technology is one of the possible alternatives. At the moment, absorption cycle is most promising technology The paper summarizes briefly the current research and development in advanced technologies of triple effect absorption chiller-heater in Japan.(omitted)

• 대한설비공학회지:설비저널
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• 제12권3호
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• pp.147-158
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• 1983

This study aims at experimental investigation on the feasibility of solar cooling in the seoul area. The system is comprised of fiat plate collectors, storage tank, auxiliary heater and Li-Br absorption chiller. Characteristics of the chi lier and the solar contribution on cooling were obtained by experiment The results show that during the days of experiment('83.6.10-6.22, 8.17-8.19) space cooling could be achieved by using soiar energy and auxiliary heater Moreover, there were time intervals during the day when cooling was possible using solar energy only without the auxiliary heater.

• 한국정밀공학회지
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• 제33권6호
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• pp.469-475
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• 2016

In this work, casting processes, such as filling and solidification, were simulated in order to accurately predict volume shrinkage defects in large-sized sand gravity casting. Turbulent flow of melted materials and a difference of solidification speed can cause volume shrinkage defects. In order to solve this problem and to understand the phenomenon, a porous filter application was studied. Two different porosities of 10 and 20 p.p.i filters were introduced into the gating system, and in view of the results so far achieved, the defect was dramatically reduced by 22%, compared to that without the use of the filter.