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차우호,최송,정백영,김병순,전시문,Cha, Woo Ho,Choi, Song,Chung, Baik Young,Kim, Byung Soon,Jeon, Si Moon 대한기계학회 2015 대한기계학회 논문집. Transactions of the KSME. C, 산업기술과 혁신 Vol.3 No.1
가스 엔진 히트 펌프는 가스 엔진의 축동력으로 압축기를 구동하는 시스템으로 전력을 거의 사용하지 않고, 엔진 폐열을 활용하기 때문에 하절기와 동절기에 전력 Peak 를 억제하는 공조기로 주목을 받고 있는 제품이다. 제품 개발 시 시스템 성능 예측이 중요하므로 이를 위해 초기 설정한 운전점에서 열교환기 및 압축기의 특성을 반영하여 반복 계산을 수행하면 최종적인 운전점을 도출할 수 있고, 가스 엔진의 성능 데이터를 활용하면 가스 엔진 히트 펌프의 정확한 효율을 예측할 수 있다. 난방 성능을 예측할 때에는 엔진 폐열이 시스템에 공급되기 때문에 외부 열을 흡입하는 구간과 엔진 폐열을 흡입하는 구간을 동시에 고려해야 예측의 정확도를 높일 수 있다. 25 마력 가스 엔진 히트 펌프의 성능을 예측한 값은 실제 측정한 값과 비교하였을 경우 5% 정도의 오차가 발생하며 향후 성능 예측 모델을 구성되는 부품 특성을 반영하면 오차의 폭이 감소될 것으로 예상된다. In this paper a prediction method of GHP performance is proposed for increasing design accuracy. Two compressors with different capacity and 2311cc gas engine are used for prediction and the target capacity of GHP is 25HP. For predicting GHP performance at first the operation points are randomly selected and then as compared with compressor performance date and heat exchanger characteristic, more accurate operating points are decided through recursive calculation. Lastly engine performance date is used for calculating gas consumption volume. Predicting heating mode performance of GHP, evaporator is separated to the two section of absorbing heat in outdoor air and in engine. From the experimental results, it was found that the simulation model is good for the predicting GHP efficiency and the difference of predicted and measured efficiency is less than 5%.
냉방운전에서의 R410A 냉매를 이용한 실내 열교환기 성능특성에 관한 실험적 연구
이종호(Jong Ho Lee),김성수(Sung Soo Kim),차우호(Woo-Ho Cha),강용태(Yong Tae Kang) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-
The objectives of this paper are to study the effects of thermal and geometric conditions on the performance of indoor heat exchangers with R410A. This study carries out experimental and numerical analysis for indoor heat exchangers. In the air side, moisture in the humid air condenses on the fin surface while the refrigerant (R410A) boils inside the smooth tube. Therefore this study uses Log Mean Enthalpy Difference (LMED) method to analyze the heat and mass transfer from the humid air to the refrigerant of R410A. The results show that fin pitch and longitudinal pitch have significant effect on the heat exchanger size. In the experimental study, the capacities of the indoor units are 3.6㎾, 4.5㎾ and 5.6㎾. This study also compares the experimental data with the calculated data for the outlet temperature and the tube length. It is found that the relative errors between the experimental data and the calculated result are 1.3%(3.6㎾), 2.2%(4.5㎾), 4.9%(5.6㎾) and 3.5%, 4.7%, 8.6% for the outlet temperature and the tube length, respectively.
예휘열(Hueeyoul Ye),김두환(Doo-Hwan Kim),이관수(Kwan-Soo Lee),차우호(Woo-Ho Cha) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
A general flow distribution model and a simple process of numerical analysis, which can be applied to multi-pass systems with manifolds, are presented. Correlations are derived from the discrete model, and numerically calculated using a modified equal pressure method. The predicted pressure distribution agrees well with the available experimental results of other researchers with the average error less than 2% for 10 branch manifolds, and 4% for 20 branch manifolds. A parametric study is performed to demonstrate the effect on the flow distribution.
실외기 토출 유량 증대를 위한 Shroud 형상 및 휀 위치 최적 설계
유기정(Kijung Ryu),김유일(Yoo-Yil Kim),이관수(Kwan-Soo Lee),차우호(Woo-Ho Cha) 대한설비공학회 2009 설비공학 논문집 Vol.21 No.11
This paper presents a numerical evaluation of the flow rate of air conditioner outdoor unit by investigating the effects of fan location and shroud shape. To determine optimal design parameters, we investigated the exhaust flow rate by changing shroud height, fan height, fan guide height, and fan width. The 3rd order central composite design was performed to select three most important parameters affecting the exhaust flow rate. According to the result of response surface method, the exhaust flow rate of the optimum model increased by 6.25% compared to that of the base model.
1차원 배열화된 냉매유로를 이용한 휜-관 열교환기 성능예측
김두환(Doo-Hwan Kim),예휘열(HueeYoul Ye),이관수(Kwan-Soo Lee),차우호(Woo-Ho Cha) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
A new method is presented for developing a simulation program which can analyze the heat transfer characteristics of fin-tube heat exchanger. This method is able to describe several types of refrigerant circuit arrangement. The delivery path of air and refrigerant properties is simplified by transforming threedimensional array into one-dimensional array. By comparing simulated results with experiment results, the deviation was 8.2%. Several fin-tube heat exchangers of different design factors and operating conditions were simulated using this program. It was shown that this program could be used for designing practical fin-tube heat exchangers.
서정아(Jeong-Ah Seo),신영기(Younggy Shin),오세재(Se-Jae Oh),차우호(Woo-Ho Cha),정진희(Jin_Hee Jeong) 대한설비공학회 2011 대한설비공학회 학술발표대회논문집 Vol.2011 No.7
Fault detection has to be proceeded by steady state filtering to get rid of transient effect associated with thermal capacity. Coefficient of variance (COV), ratio of standard deviation devided by moving average, was employed as steady-state filter. Engine speed and refrigerant pressures were selected as parameters representing system dynamics. The filtered values were registered as members of steady-state DB. They were found to show good functional relationship with ambient temperature. The relationship was fitted with a second order polynomial and the distribution bounds of the data around the fitted curve were expressed in terms of confidence intervals which were calculated from the assumption of Student's t-distribution. Fault data were compared with the steady-state data obtained during normal operation. The fault data were easily isolated from the normal one. To make the fault-detection algorithm sense, more fault cases have to be tested.
예휘열(Huee-Youl Ye),김두환(Doo-Hwan Kim),이관수(Kwan-Soo Lee),차우호(Woo-Ho Cha) 대한설비공학회 2009 설비공학 논문집 Vol.21 No.3
A general flow distribution model and a simple process of numerical analysis, which can be applied to multi-pass systems with manifolds, are presented. A numerical procedure, namely a modified equal pressure method based on the discrete model, was developed to predict flow rates at branch tubes. The predicted pressure distribution agreed well with the previous research with the average error less than 11%. A parametric study was performed to demonstrate the effect on the flow distribution.
김두환(Doo-Hwan Kim),예휘열(Huee-Youl Ye),이관수(Kwan-Soo Lee),차우호(Woo-Ho Cha) 대한설비공학회 2008 설비공학 논문집 Vol.20 No.12
A new method is presented for developing a simulation program which can analyze the heat transfer characteristics of fin-tube heat exchanger. This method is able to describe several types of refrigerant circuit arrangement. The delivery path of air and refrigerant properties is simplified by transforming three-dimensional array into one-dimensional array. By comparing simulated results with experiment results, the deviation was 8.2%. Several fin-tube heat exchangers of different design factors and operating conditions were simulated using this program. It was shown that this program could be used for designing practical fin-tube heat exchangers.
유기정(Ki-Jung Ryu),예휘열(Huee-Youl Ye),이상봉(Sang-Bong Lee),이관수(Kwan-Soo Lee),차우호(Woo-Ho Cha) 대한설비공학회 2009 대한설비공학회 학술발표대회논문집 Vol.2009 No.-
This paper presents a numerical evaluation of the flow rate of air conditioner outdoor unit as function of shroud design parameters. To determine the optimal design parameters, we investigated the flow rate by changing bell mouth height, fan height, fan guide height, fan width. The evaluation of the relative priority of the design parameters was performed to choose three important parameters in order to use a response surface method. The flow rate of the optimum model, compared to that of the base model, was increased by about 6.25%.