• International Journal of Air-Conditioning and Refrigeration
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• v.6
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• pp.1-13
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• 1998

The basic heat transfer process that occurs in a building can best be illustrated by an electrical circuit network. Present paper reports the dynamic simulation of annual energy consumption in an office building by the thermal resistance capacitance network method. Unsteady thermal behaviors and annual energy consumption in an office building were examined in detail by solving the simultaneous circuit equations of thermal network. The results are used to evaluate the accuracy of the modified BIN method for the energy consumption analysis of a large building. Present thermal resistance-capacitance method predicts annual energy consumption of an office building with the same accuracy as that of response factor method. However, the modified BIN method gives 15% lower annual heating load and 25% lower cooling load than those from the present method. Equipment annual energy consumptions for fan, boiler and chiller in the HVAC system are also calculated for various control systems as CAV, VAV, FCU+VAV and FCU+CAV. FCU+CAV system appears to consume minimum annual energy among them.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.5
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• pp.575-582
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• 1988

This paper presents an energy analysis on the VAV system of 10-story building in Seoul using DOE-2 program and Modified Bin Method. The use of VAV system is an excellent means of saving energy in new buildings and/or retrofit. The fan control techniques considered are cycling, discharge dampers, inlet vanes, and motor speed control. The monthly and annual energy consumption is calculated for fan control techniques, components, and chiller types. The results of annual fan electricity use are compared using DOE-2 and Modified Bin Method, and show fairly good agreement. In addition, factors affecting energy consumption are also described.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.49-49
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• 2000

당사는 1991년 6월에 설립된 후 반도체 장비의 국산화 개발에 주력하고 있다. Thermoelectric module typer Chiller 및 Dry gas scrubber를 국산화 하였으며 THC(Temperature & Humidity Controller)를 개발하여 국내 및 미국에 특허를 출원중에 있으며 기업 부설연구소를 통해 계속하여 각종 제품을 연구 개발하고 있다. 이외 다수의 제품을 보유하고 있으며 기업 부설연구소를 통해 계속하여 각종 제품을 연구 개발하고 있다. 이외 다수의 제품을 보유하고 있으며 진공관련 제품으로는 미국 MDC사 Vacuum components, e-beam vaporation system. ISI사 electrical and optical components, US Inc. 사 Sputter system, SBC사 Bellows. 일본 IKC사 Bellows, Vacuum components, Vacuum system을 취급하고 있다. 1998년에 경기도 및 중소기업청으로부터 유망중소기업 및 벤처기업 인증을 획득하였으며 1999년 12월에 경기도 및 중소기업청으로부터 유망중소기업 및 벤쳐기업 인증을 획득하였으며 1999년 12월 KOSDAQ에 등록하였다. 중소기업 수출기업화 사업 대상기업으로 선정되었으며 1999년 12월 KOSDAQ에 등록하였다.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1031-1035
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• 2008

The importance of the more efficient cogeneration system is emphasized. Also the more clean energy is needed at recent energy system. The cogeneration system using Lean burn engine is more preferred to the system using Rich burn engine because of the electrical efficiency. Although the cogeneration system using Lean burn engine is economically preferred, because of the NOx emission level, the system using Rich burn engine with 3-way catalyst can only be used in Korea. The NOx regulation level is 50ppm at oxygen level 13%. The cogeneration hybrid system is consist of Lean burn gas engine, afterburner, boiler, economizer, DeNOx catalyst, combustion catalyst, absorption chiller, cooling tower and grid connection system. The system was accurately evaluated and the result is following ; 90% total efficiency, below 10ppm NOx, 50ppm CO, 25ppm UHC. The cogeneration hybrid system can meet the NOx level and exhaust gas regulation. It can achieve the clean combustion gas and efficient cogeneration system.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.286-291
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• 2001

This paper describes an optimal scheduling for ice slurry systems for energy cost saving. The optimization technique applied in the study is the dynamic programming method, for which the state variable is the storage in the ice storage tank and the control variable is the state of chiller's on-off switching. Though the costs during charge period is included in optimization by taking the average cost of ice per hour for slurry making, the time horizon for the simulation is limited building cooling period because accurate charge rate from the ice maker into the ice storage tank cannot be estimated during the charge period. In the operating simulation after optimizing procedure, energy consumption and operating cost for the optimal control are calculated and compared with them for a conventional control with one case of cooling load profile.

• Corrosion Science and Technology
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• v.9 no.3
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• pp.137-141
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• 2010

Sodium nitrite is widely used as one of the popular corrosion inhibitors for the protection of ferrous metal in closed cooling water system, such as a diesel engine and a chiller. The optimum treatment conditions are studied through laboratory tests using linear polarization resistance (LPR) technique. Corrosion rate of the carbon steel electrode could be maintained less than $2.5{\times}10^{-3}$ mmpy in the test condition of 500 ppm as ${NO_2}^-$, 200 ppm as $Cl^-$, $70^{\circ}C$ and pH 6.8. The pH control is confirmed not to be an important factor in the protection of carbon steel by sodium nitrite inhibitor. The addition of tolyltriazole was needed for the protection of the copper alloy in the sodium nitrite treatment system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.722-728
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• 2001

Applying a general coupled lateral and torsional vibration finite element model of gear pair element this paper intends to look into in detail the coupled lateral and torsional vibration characteristics in a turbo-chiller rotor bearing system, having a bull-pinion speed increasing gear. Investigations have been carried out systematically by comparing the uncoupled and coupled analyses natural vibration frequencies and their mode shapes upon varying the gear mesh stiffness, and also by comparing the strain energies of lateral and torsional vibration modes. Results have shown that some modes may have coupled lateral and torsional mode characteristics as the gear mesh stiffness increases over a certain value, and moreover that their associated dominant modes may be different from their initial modes, i.e., the dominant mode changes from an initial torsional one to a lateral one or from an initial lateral one to a torsional one.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.333-337
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• 2011

Central control air-conditioning systems are being replaced with individually controlled air-conditioning system in the university. The amount of growth of electricity consumption is due to the increasing demand of electric heat pump. In winter and summer, the energy consumption showed a tendency to increase. On the other hand, showed less energy in spring and autumn. Increase the amount of electricity than the degree of decline in gas consumption was higher. Can be considered as transitional phenomena. Because electric heat pump, gas driven heat pump and the absorption chiller-heater are used at the same time in some of the buildings.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.5
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• pp.199-205
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• 2014

The integration of FC (Fuel Cell) and GSHP (Ground Source Heat Pump) hybrid system could produce a synergistic advantage in thermal and electric way. This study intends to analyse the economical aspect of a FC integrated GSHP hybrid system compared to the conventional system which is consisted with a boiler and a chiller. Based on the hourly simulation, the study indicated that GSHP system and FC+GSHP hybrid system could reduce the energy consumption on a building. The method of the economic assessment has been based on IEA ECBCS Annex 54 Subtask C SPB(Simple Payback) method. The SPB was calculated using the economic balanced year of the alternative system over the conventional (reference) system. The SPB of the alternative systems (GSHP and FC+GSHP) with 50% initial incentive was 4.06 and 26.73 year respectively while the SPB without initial incentive of systems was 10.71 and 57.76 year.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.30-35
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• 2008

This paper describes a fault detection and diagnosis (FDD) system developed for the heat source apparatus in building air-conditioning system. As HVAC&R systems in building become complex and instrumented with highly automated controllers, the processes and systems get more difficult for the operator to understand and detect the mal-functions. Poorly maintained, degraded, and improperly controlled equipment wastes an estimated 15% to 30% of energy used in commercial building. When operating a complex facility, FDD system is beneficial in equipment management to provide the operator with tools which can help in decision making for recovery from a failure of the system. Automated FDD for HVAC&R system has the potential to reduce energy and maintenance costs and improves comfort and reliability. Over the last decade there has been considerable research for developing FDD system for HVAC&R equipment. However, they are being made too much of a theoretical study, so only a small of FDD methods are deployed in the field. This study deduced an actual defect source for the heat source apparatus and suggested a low price FDD method which is ready to be deployed in the field.