http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
신영기,Shin, Younggy 한국플랜트학회 2022 플랜트 저널 Vol.18 No.2
The conventional communication method using mud flow pressure waves has a speed of 1-2 bps, so it takes a long time to communicate, making real-time control impossible. Although the sound wave communication method for improving the communication speed by 10 times or more has been commercialized, its use is limited due to its high price and there are not many application cases. In this study, the simulator corresponding to the facility was developed to develop performance similar to the actual test results. For simulating sound wave communication through a drill pipe, we proposed a governing equation that can simulate friction damping by mud and developed a numerical analysis model. The attenuation factor was corrected by comparing it with the attenuation rate of sound wave energy at the drilling site. The developed numerical analysis model was applied to the QPSK modulation type communication algorithm to confirm the excellent performance of the communication error rate of 0.04% in the ground. This is the communication performance under the condition that noise has not been mixed yet, and in order to apply it, the technology of reproducing the actual noise signal for mixing by securing the field noise data was established.
신영기(Younggy Shin) 대한설비공학회 2010 설비공학 논문집 Vol.22 No.5
Car HVAC is one of main factors influencing a potential customer’s first impression. It should be fault-free, which requires the most stable control performance. So, the control algorithm consists of a proportional feedback only, not with an integral action needed for elimination of steady-state errors. To reduce the errors and make the response faster, feedforward algorithm based on predicted thermal load is added. To evaluate the performance, car HVAC is dynamically modelled and its control logic is simulated. The results shows that the proportional feedback leads to about 4 ℃ of steady-state error. When the feedback is combined with the feedforward algorithm and with a set value update based on disturbances, it predicts less than 1 ℃ of control error and improved thermal comfort.
신영기(Younggy Shin) 대한설비공학회 2014 설비공학 논문집 Vol.26 No.5
A fault detector was developed for heat exchangers of a hybrid heat pump (HP) for household. The proposed detector can be applied directly to raw operating data. It is to monitor a tracking error between a measured saturation temperature and its state observer. The observer was estimated from a state-space model simulating dynamics of a heat exchanger. The real hybrid HP was substituted with a dynamic simulator that implemented two-phased heat transfer and was validated by experimental data. And artificial fault data were generated using the simulator. Diagnosing the data showed the following. The residual calculated from the state observer error shows a relatively robust consistency with respect fouling level. The fault detector is practically useful because it detects a threshold fouling beyond which the performance starts to deteriorate significantly.
Reverse Brayton 사이클과 Claude 사이클 기반 LNG 재액화 공정의 동특성 운전성능 비교
신영기(Younggy Shin),서정아(Jung-A Seo),이윤표(Yoon Pyo Lee) 대한설비공학회 2008 설비공학 논문집 Vol.20 No.12
A dynamic model to simulate LNG reliquefaction process has been developed. The model was applied to two candidate cycles for LNG reliquefaction process, which are Reverse Brayton and Claude cycles. The simulation was intended to simulate the pilot plant under construction for operation of the two cycles and evaluate their feasibility. According to the simulation results, both satisfy control requirements for safe operation of brazed aluminum plate-fin type heat exchangers. In view of energy consumption, the Reverse Brayton cycle is more efficient than the Claude cycle. The latter has an expansion valve in addition to the common facilities sharing with the Reverse Brayton cycle. The expansion valve is a main cause to the efficiency loss. It generates a significant amount of entropy associated with its throttling and increases circulation flow rates of the refrigerant and power consumption caused by its leaking resulting in lowered pressure ratio. It is concluded that the Reverse Brayton cycle is more efficient and simpler in control and construction than the Claude cycle.
이중효용 흡수식 냉온수기 동특성 모델 개발 및 실험결과 비교
신영기(Younggy Shin),서정아(Jung-A Seo),조현욱(Hyun-wook Cho),남상철(Sang-Chul Nam),정진희(Jin-Hee Jeong) 대한설비공학회 2008 설비공학 논문집 Vol.20 No.12
A dynamic model has been developed to simulate dynamic operation of a real double-effect absorption chiller. Dynamic behavior of working fluids in main components was modeled in first-order nonlinear differential equations based on heat and mass balances. Mass transport mechanisms among the main components were modeled by valve throttling, ‘U’ tube overflow and solution sub-cooling. The nonlinear dynamic equations coupled with the sub-routines to calculate thermodynamic properties of working fluids were solved by a numerical method. The dynamic performance of the model was compared with the test data of a commercial medium chiller. The model showed a good agreement with the test data except for the first 5,000 seconds during which different flow rates of the weak solution caused some discrepancy. It was found that the chiller dynamics is governed by the inlet temperatures of the cooling water and the chilled water when the heat input to the chiller is relatively constant.
신영기(Younggy Shin),김태형(Taehyung Kim),김현수(Hyunsoo Kim) 대한설비공학회 2013 대한설비공학회 학술발표대회논문집 Vol.2013 No.11
The present study has been conducted to investigate a feasibility of implementing an energy self-sufficient island. A typical hotel with 179 rooms was assumed to be a main consumer in a deserted island and its electricity demand was met by 1.3 MW wind turbines and 0.932 MW PV modules. And 250 MWh battery and 81.75 MWh reverse hydro reservoir were applied for energy storage. Dynamic energy balance over a year was achieved. Capital cost analysis, however, revealed that battery cost is too expensive to make this study feasible. So, the result suggests that wind turbines must be installed as many as possible to minimize battery size requirement and excess energy should be utilized to power auxiliary facilities such as waste water treatment.
GHP 운전시 COV에 의한 정상상태 판별 및 이상검출 방법 연구
신영기(Younggy Shin),오세재(Se-Jae Oh),정진희(Jin_Hee Jeong) 대한설비공학회 2011 설비공학 논문집 Vol.23 No.11
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 by visual inspection because of varying average and random data interval. Fault data were compared with the steady-state data obtained during normal operation. The fault data were easily isolated from the fault-free one. To make such isolation reliable, tests to construct good DB should be designed in a systematic way.
신영기(Younggy Shin),김의종(Eui-Jong Kim),이경호(Kyoung-ho Lee) 대한설비공학회 2018 대한설비공학회 학술발표대회논문집 Vol.2018 No.11
An optimization algorithm is developed based on a simulation case of a single family house model and a twon equipped with renewable energy facility. Linear programming is adopted to minimize electricity bill while state variables of energy storage elements within allowable constraints. For optimization, the house and the seasonal thermal storage facility were simulated by RC elements. It was found that the linear models to build linear programming logics were useful enough for dynamic simulation and optimal scheduling. The comparison with GenOpt, a global optimization tool, illustrated the merit of LP by linear models. But a care has to be taken in applying a linear model to a real plant because of limited flexibility due to the nature of approximation, which lacks detailed causality.