냉방부하 추정을 위한 온도와 습도 예측에 관한 연구

유성연,이제묘,한규현,한승호 대한설비공학회 2007 설비공학 논문집 Vol.19 No.5

To estimate the cooling load for the following day, outdoor temperature and humidity are needed in hourly base. But the meteorological administration forecasts only maximum and minimum temperature. New methodology is proposed for predicting hourly outdoor temperature and humidity by using the forecasted maximum and minimum temperature. The correlations for normalized outdoor temperature and specific humidity has been derived from the weather data for five years from 2001 to 2005 at Seoul, Daejeon and Pusan. The correlations for normalized temperature are independent of date, while the correlations for specific humidity are linearly dependent on date. The predicted results show fairly good agreement with the measured data. The prediction program is also developed for hourly outdoor dry bulb temperature, specific humidity, dew point, relative humidity, enthalpy and specific volume.

PERFORMANCE OF AIR CONDITIONERS WITH A GAS-LIQUID SEPARATION CONDENSER AND ONE-TANK LAMINATED EVAPORATO

유성연,지명석,이대웅 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.5

In this study, a parallel flow condenser and laminated evaporator for an automotive air-conditioning system were modified to improve performance. Gas-liquid separation type condensers, in which the condenser and receiver drier are integrated, and one-tank laminated type evaporators were developed, and their performances were investigated experimentally using HFC-134a. Heat transfer characteristics in the condenser are examined by means of air temperature, air velocity entering the condenser and inlet pressure of the refrigerant; heat transfer characteristics in the evaporator are examined by means of air temperature, relative humidity, flow rate of air, outlet pressure of refrigerant and superheat. Pressure drops for both evaporator and condenser are also measured, and correlations for pressure drop are derived for the condenser and evaporator, respectively. Air velocity and mass flow rate of the refrigerant have a significant effect on the overall heat transfer coefficient, and flow pass is not significantly influenced by the cooling capacity of the condenser. The overall heat transfer coefficient of the evaporator increases as air flow rate, air temperature and relative humidity increases. In this study, a parallel flow condenser and laminated evaporator for an automotive air-conditioning system were modified to improve performance. Gas-liquid separation type condensers, in which the condenser and receiver drier are integrated, and one-tank laminated type evaporators were developed, and their performances were investigated experimentally using HFC-134a. Heat transfer characteristics in the condenser are examined by means of air temperature, air velocity entering the condenser and inlet pressure of the refrigerant; heat transfer characteristics in the evaporator are examined by means of air temperature, relative humidity, flow rate of air, outlet pressure of refrigerant and superheat. Pressure drops for both evaporator and condenser are also measured, and correlations for pressure drop are derived for the condenser and evaporator, respectively. Air velocity and mass flow rate of the refrigerant have a significant effect on the overall heat transfer coefficient, and flow pass is not significantly influenced by the cooling capacity of the condenser. The overall heat transfer coefficient of the evaporator increases as air flow rate, air temperature and relative humidity increases.

나프탈렌승화법을 이용한 열전달 측정

유성연,Yoo, S.Y. 대한설비공학회 1992 설비저널 Vol.21 No.5

상변화를 수반하는 이상류(二相流)가 흐르는 원관 주위에서의 난류 열전달

유성연,김유,정명균,Yoo S. Y.,Kim Y.,Chung M. K. 대한설비공학회 1987 설비저널 Vol.16 No.1

Turbulent convective heat transfer phenomenon which occur around the evaporator section of heat pump were analyzed experimentally. For this purpose a special wind tunnel and a heat pump system were designed and fabricated. Evaporator section was installed perpendicular to air flow direction and part of the evaporator was made of a glass tube for visual observation. The velocity distribution, turbulent intensity and temperature distribution were measured by hot wire technique and thermocouples. An experimental correlation for the convective heat transfer coefficient was obtained and the result is somewhat higher than the value calculated from Hilpert equation. The difference in two equations is believed to be due to the boning effect inside the evaporator tube.

EXPERIMENTAL STUDY ON PERFORMANCE OF AUTOMOTIVE AIR CONDITIONING SYSTEM USING R-152a REFRIGERANT

유성연,이대웅 한국자동차공학회 2009 International journal of automotive technology Vol.10 No.3

Recently, as climate changes have manifested worldwide, every country is making efforts to prevent ozone depletion and global warming. In the automotive industry, R-134a refrigerant is widely used in air conditioning systems because it has zero ozone depletion potential (ODP). Unfortunately, its global warming potential (GWP) is high. Therefore, alternative refrigerants are needed as a replacement for R-134a. R-152a is considered to be one of the better alternative refrigerants due to zero ODP and low GWP. In this paper, the performance of an automotive air conditioning system using R-134a and one using R-152a are compared experimentally at the bench level. The experimental apparatus simulated a real automotive air conditioning system consisting of a cabin and engine room structure. The cooling capacity, condensing capacity, coefficient of performance (COP) and power consumption characteristics of the automotive air conditioning system are evaluated by changing the air velocity entering the condenser and the compressor rotation speed with the optimized refrigerant charge amount. Also, the performance of the R-152a system was investigated by changing the thermostatic expansion valve which is set of values. The results of this study show that the R-152a system is slightly better than the R-134a system, not only under driving conditions but also under idling condition. R-152a refrigerant thus shows promise as an alternative refrigerant to replace the current standard, R-134a, in automotive air conditioning systems.

한국 유도 기원설의 변화과정 연구

유성연 대한무도학회 2023 대한무도학회지 Vol.25 No.2

이 연구는 대한제국부터 해방 직후까지 한국 유도 기원설의 변화과정을 심도 있게 고찰하여 한국적유도 사상이 정착되는 과정에 대해 밝히고자 한다. 첫째, YMCA유도반 초대 사범이었던 나수영은 신라의 유술인 천풍해세류가 일본으로 건너가 유도가 되었다고 주장하였다. 그의 이러한 주장은 제자들에 의해 구전으로 전파되어 한국 유도 기원설의 시발점이 된다. 둘째, 민족주의 사학자들은 유도는 고려시대의유술인 수박(手搏)이 일본으로 건너가 완성된 것이라 주장하였다. 이러한 주장들이 해방 직후 융합되어한국 유도 이식설의 배경이 된다. 셋째, 해방 직후 일제의 잔재를 청산하는 과정에서 유도인들은 무예도보통지에 나와 있는 신법(身法), 수법(手法), 각법(脚法)이 일본에 이식되어 손기술, 발기술, 허리기술로발전되었다는 구체적 주장을 하게 된다. 이상과 같이 한국 유도 기원설은 민족주의 사학자들의 역사 인식에 영향을 받았으며 여기에 경기 유도인들이 민족주의적 내셔널리즘 바탕으로 유도 기술을 문화 변용하여 한국적 유도 사상을 완성 시켰다.

납작관형 핀-관 열교환기의 국소 및 총합 열전달 특성에 관한 실험적 연구

유성연,정민호,박동성,이상섭 대한설비공학회 2002 설비공학 논문집 Vol.14 No.11

Local and overall heat transfer characteristics of fin-flat tube heat exchangers with and without vortex generators are investigated. Local heat transfer coefficients are measured with the heat exchanger model using naphthalene sublimation technique. In case of a fin-flat tube heat exchanger without vortex generators, only the horseshoe vortices formed around tubes augment the heat transfer. On the other hand, longitudinal vortices created artificially by vortex generators enhance heat transfer dramatically in case of a fin-flat tube heat exchanger with vortex generators. Overall heat transfer coefficients are measured with the prototype of the fin-flat tube heat exchanger with and without vortex generators in a wind tunnel and results are compared with those of a fin-circular tube heat exchanger with wavy fin. Friction losses for heat exchangers are also measured and compared. The fin-flat tube heat exchanger with vortex generators is found to be more effective than the fin-circular tube heat exchanger with wavy fin.

열전소자 및 열전냉각장치의 성능에 관한 연구

유성연,홍정표,심우섭 대한설비공학회 2004 설비공학 논문집 Vol.16 No.1

Thermoelectric module is a device that can produce cooling in a direct manner using the electrical energy. The purpose of this study is to investigate the performance of thermoelectric module and cooling system equipped with the thermoelectric module. The performance of a thermoelectric module is estimated using two methods; theoretical analysis based on one-dimensional energy equations and experimental tests using heat source, heat sink and brass conduction extenders. For the thermoelectric cooling system, the temperatures in the chamber are recorded and then compared with those of lumped system analysis. The results show that the cooling capacity and COP of the thermoelectric module increases as the temperature difference between hot and cold surface decreases, and there is particular current at which cooling capacity reaches its maximum value. The experimental results for the thermoelectric cooling system are similar to those of lumped system analysis.

시설공사 내역서 표준화 및 간소화에 관한 연구

유성연,이제묘,박준택,류윤수,김중곤,Yoo Seong-Yeon,Lee Je-Myo,Park Jun-Tack,Ryoo Yoon-Soo,Kim Jung-Gon 한국공기청정협회 2005 空氣淸淨技術 Vol.18 No.1

Construction work is an art of making something out of nothing. To run the construction project smoothly, budget, organization and engineering should be balanced. Standardization and simplification of construction bill are needed in order to maximize the

열전자소자의 냉각성능에 관한 연구 ( A Study on the Cooling Performance of Thermoelectric Module )

유성연,주병주,감정헌,이상윤,김광영 대한기계학회 1995 대한기계학회 춘추학술대회 Vol.- No.-