• 전자공학회논문지B
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• 제30B권11호
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• pp.47-55
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• 1993

This paper is to design an autobalancing system based-on microprocessor for hemodiafiltration (HDF) system. The proposed system consist of motor control part, thermostatic control part, alarm system and electronic scale which ar automatically controlled by microprocessor. Conventional hemodialysis system can not remove medium molecular articles but hemodialysis system with the proposed system can remove and infuse substitute to the patient. This system can be easily interfaced with any other conventional HD system. The results obtained from performance evaluation of the proposed system are suitable for clinical supporting system.

• 한국자동차공학회논문집
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• 제6권2호
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• pp.203-211
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• 1998

The system performance of an automobile air conditioning system with variations of charging conditions has been investigated experimentally. An automobile air conditioning system was composed of laminated type evaporator, parallel flow type condenser, swash plate type com-pressor, externally equalized thermostatic expansion valve and receiver drier. The objective of this study was to quantify the influence of the refrigerant charge under the steady state operation of an automobile air conditioning system. The results indicated that a 10% undercharge caused a 10% reduction in the capacity of evaporator.

• 한국생물환경조절학회:학술대회논문집
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• 한국생물환경조절학회 2003년도 춘계 학술대회 논문집
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• pp.38-43
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• 2003

우리나라의 시설재배면적은 2001년 현재 52,135ha이고 이중가온 재배면적이 12,710ha로 전체 시설재배면적의 25%에 해당하며 또한 난방비용이 경영비 중 차지하는 비중이 시설재배 선진국의 15%에 비하여 25-30%을 차지하고 있어 난방비의 비중이 높다. 온풍난방시 시설내 에너지 절감을 위한 국내의 연구는 주로 보온, 난방기의 위치 및 Duct의 토출구 간격 및 직경(Kim 등, 1994), 난방배관 구조개선(Kwon 등, 1992)등으로 연구되어 왔다. (중략)

• 설비공학논문집
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• 제14권4호
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• pp.304-314
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• 2002

Performance analysis of the automotive air-conditioning system is conducted by using computer simulation, and performance tests are carried out by using the climate wind tunnel in order to verify simulation. Evaporator and condenser were modeled by using empirical correlation which was obtained from calorimeter data, and compressor was modeled by using map based method. The steady state thermodynamic conditions of refrigerant satisfying mass and energy balance were assumed in the simulation program for automotive airconditioning system. The system performance was analyzed by finite difference method until differential air enthalpy between evaporator inlet and outlet becomes converged. Simulation results are in good agreement with experimental results at most operating conditions. Variation of discharge temperature and pressure of compressor, outlet temperature of evaporator, cooling capacity, and COP were investigated in term of air volume flow rate for evaporator, compressor capacity, compressor speed, superheat of thermostatic expansion valve, and diameter of suction line.

• 설비공학논문집
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• 제10권2호
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• pp.202-216
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• 1998

A computer simulation for the performance analysis of automobile air conditioning components is carried out for the various operating conditions. The automobile air conditioning system consists of laminated type evaporator, swash plate type compressor, parallel flow type condenser, externally equalized thermostatic expansion valve and receiver drier. The overall heat transfer coefficient and the pressure drop in laminated type evaporator were obtained through experiments. In parallel flow type condenser, the performance analysis computer program using the empirical equation for heat transfer coefficient has been developed and the results are compared with experimental results. A model for matching the performance analysis programs of respective components .of automobile air conditioning system is introduced. Further, the effects of varying condenser size and refrigerant charge on the performance of automobile air conditioning system are discussed clearly.

• 한국지열·수열에너지학회논문집
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• 제12권4호
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• pp.21-26
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• 2016

In this study, the control strategies of indoor air temperature in floor radiant heating system were researched by computer simulation. The temperature difference based time control method using the difference of indoor set temperature and indoor temperature is compared with the existing On-Off control one for heating control performances. As a result, the temperature difference based time control method shows better thermal environmental characteristics in case of selected operational conditions in comparison with existing control one.

• 동력기계공학회지
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• 제14권3호
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• pp.19-24
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• 2010

The purpose of this study is to develop a snow melting system using the pulsating heat pipe(PHP). The experimental apparatus is consisted of a PHP, a concrete structure, a constant water thermostatic bath and a flowmeter. The experiment was performed at the outdoor air temperature of $-8^{\circ}C$ and inlet temperature of hot water of $75^{\circ}C$. PHP is the closed and non-loop type heat exchanger which is charging R-410A as an operating fluid. As experimental results, the temperature profile of vertical and horizontal orientation of concrete structure was measured with operating time. The heat flux of the snow melting was required more than 300 $W/m^2$. We confirmed that the snow melting system using the PHP was useful for anti-freezing road.

• 설비공학논문집
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• 제11권6호
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• pp.928-936
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• 1999

An experimental study was performed to investigate characteristics of an inverter driven water-to-water refrigeration system with a variation of compressor frequencies and expansion devices. The frequency of a compressor varied from 30Hz to 75Hz, and performance of the systems applying three different expansion devices such as capillary tube, thermostatic expansion valve(TXV), and electronic expansion valve(EEV) were measured. The load conditions were altered by varying the temperature of the secondary fluid entering condenser and evaporator with a constant flow rate. When the test conditions were deviated from the standard value(rated value), TXV and EEV showed better performance than capillary tube due to optimum control of mass flow rate and superheat. In the present study, it was observed that the variable area expansion device had better performance than constant area expansion device in an inverter refrigeration system due to active control of flow area with a change of compressor frequency and load conditions.

• 설비공학논문집
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• 제14권1호
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• pp.10-20
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• 2002

A dynamic model of a water heater system heated by a heat pump was developed. The water heater system was composed of heat pump and hot water reservoirs. Finite volume method (FVM) was applied to describe the heat exchangers. A new constraint on electronic expansion valve (EEV) or thermostatic expansion valve (TXV) that can control superheat after the evaporator was developed. Dynamic performances were evaluated for various sizes of the reservoir. In order to compare those performances, time scale was normalized by time constant representing the characteristics of reservoir size. Time constant was determined from quasi steady-state simulation of the system. From the simulation, the size of the water heater reservoir was found to have a large influence on the transient performance of the sys- tem. Therefore, the optimization of the reservoir size is needed in a design process.

• 태양에너지
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• 제6권2호
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• pp.33-42
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• 1986

The purpose of this paper is to research the performance of the energy in a case of the earth bermed House designed to be suitable for Korean situation in comparison with a conventional housing. The result of this study can be summerized as follows; 1) Heating energy of the earth bermed house is saved 40.1% than that of the conventional housing in Korea. 2) The time-lag of the earth bermed house is 57 minutes longer than that of a conventional housing on account of the thermal capacity, so the earth bermed house has much more satisfactory thermostatic mitigation effect rather than the conventional housing.