Desalination plants are generally studied with higher operating costs compared to water supply facilities. This study was conducted to reduce the cost of water production and to preserve existing water resources. Therefore, the purpose of this study was to utilize the control valves to increase maximum efficiency, thereby reducing the power of the pumps and operating costs. Specific energy consumption was shown to reduce the process operating power by up to 1.7 times from 6.17 to 3.55 kWh/m3 based on seawater reverse osmosis 60 bar. In addition, the water intake process was divided into pre, inter, and post-according to the use method of blasting, and the water treatment process was divided into pre, inter, and post blending. In order to reduce power consumption, the blending process was combined to operate the facility, which resulted in the reduction of power consumption in the order post > pre-inter> inter blending.

본 연구는 방울토마토 재배 단동온실에 공기순환팬을 설치하고 공기순환팬이 온실 내 온도 및 습도 분포, 에너지소비량에 미치는 영향을 분석하였다. 공기순환팬은 날개 크기 230mm의 Stainless 팬으로, Lee 등(2016)의 연구결과를 참고하여 시험구 온실에 9m 간격으로 총 18 대를 설치하였다. 온실 내부 온습도는 온실 길이방향으 로 4등분하여 1/4 지점과 3/4 지점의 중앙에 센서를 설치하고 0.8m, 1.8m 높이 2곳의 온습도를 난방을 주로 하는 야간(오후 6시~다음 날 오전 7시)에 5분 간격으로 측정하였다. 에너지소비량은 각 온실에 위치한 온수펌프의 유량, 온수 출수부와 환수부의 온도차를 측정하여 계산하였다. 공기순환팬을 사용하지 않았을 때 측점 간 온도차 및 습도차의 평균값은 0.75oC, 2.19%였으며 공기 순환팬 사용 시 측점 간 온도차 및 습도차의 평균값은 0.42oC, 1.27%로 감소하였다. 공기순환팬 설치 온실과 미설치 온실의 누적 에너지소비량은 각각 4,673kWh, 4,009kWh로 공기순환팬 설치 온실에서 약 14.2%의 에너지를 적게 소모하였다. 이러한 결과로 보아 온실 내 공기순환팬 사용은 공기를 지속적으로 교반시켜 주어 온실 전체의 온도 및 습도를 균일하게 만들고, 공기의 온도가 빠르게 변하지 않도록 해주어 난방 장치의 가동 시간과 에너지소비량을 줄일 수 있다.

Most of steam power plant in Korea are heating the feed water system to prevent freezing water flowing in the pipe in winter time. The heating system is operated whenever the ambient temperature around the power plant area below 5 degree Centigrade. But this kind of heat supplying system cause a lot of energy consuming. If we think about the method that the temperature of the each pipe is controled by attaching the temperature measuring sensor like RTD sensor and heat is supplied only when the outer surface temperature of the pipe is under 5 degree Centigrade, then we can save a plenty of energy. In this study, the computer program package for simulation is used to compare the energy consumption load of both systems. Energy saving rate is calculated for the location of Youngweol area using the data of weather station in winter season, especially the January' severe weather data is analyzed for comparison. Various convection heat transfer coefficients for the ambient air and the flowing water inside the pipe was used for the accurate calculation. And also the various initial flowing water temperature was used for the system. Steady state analysis is done previously to approximate the result before the simulation. The result shows that the temperature control system using RTD sensor represents the high energy saving effect which is more than 90% of energy saving rate. Even in the severe January weather condition, the energy saving rate is almost 60%.

The purpose of this study suggests a personalized algorithm of physical activity energy expenditure prediction through comparison and analysis of individual physical activity. The research for a 3-axial accelerometer sensor has increased the role of physical activity in promoting health and preventing chronic disease has long been established. Estimating algorithm of physical activity energy expenditure was implemented by using a tri-axial accelerometer motion detector of the SVM(Signal Vector Magnitude) of 3-axis(x, y, z). A total of 10 participants(5 males and 5 females aged between 20 and 30 years). The activities protocol consisted of three types on treadmill; participants performed three treadmill activity at three speeds(3, 5, 8 km/h). These activities were repeated four weeks.

Four different buildings having various wall construction are analyzed for the effect of wall mass on the thermal performance and inside building air and wall temperature transient and also for calculating the energy consumption load. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one-dimensional, linear, partial differential equations is obtained using the Laplace transform method, Bromwich and modified Bromwich contour method. A simple dynamic model using steady state analysis as simplified methods is developed and results of energy consumption loads are compared with results obtained using the analytical solution. Typical Meteorological Year data are processed to yield hourly average monthly values. This study is conducted using weather data from two different locations in Korea: Daegu having severe weather in summer and winter and Jeju having mild weather almost all year round. There is a significant wall mass effect on the thermal performance of a building in mild weather condition. Buildings of heavyweight construction with insulation show the highest comfort level in mild weather condition. A proportional controller provides the higher comfort level in comparison with buildings using on-off controller. The steady state analysis gives an accurate estimate of energy load for all types of construction. Finally, it appears that both mass and wall insulation are important factors in the thermal performance of buildings, but their relative merits should be decided in each building by a strict analysis of the building layout, weather conditions and site condition.

Wastewater treatment plant(WWTP) has been recognized as a high energy consuming plant. Usually many WWTPs has been operated in the excessive operation conditions in order to maintain stable wastewater treatment. The energy required at WWTPs consists of various subparts such as pumping, aeration, and office maintenance. For management of energy comes from process operation, it can be useful to operators to provide some information about energy variations according to the adjustment of operational variables. In this study, multiple regression analysis was used to establish an energy estimation model. The independent variables for estimation energy were selected among operational variables. The R2 value in the regression analysis appeared 0.68, and performance of the electric power prediction model had less than ±5% error.

본 연구는 초등학교 5, 6학년 학생을 대상으로 학교에서의 수업 시수 차이에 따른 학외활동의 소비시간 변화와 활동종류별 평균활동계수를 파악하여 초등학생의 활동량을 증가시킬 수 있는 방안 마련의 기초자료를 제공하고자 한다. 초등학생의 활동 내역을 사전 조사하여 기존의 인터넷 프로그램을 보완한 다음, 서울시내 거주 초등학교 5, 6학년 학생 386명을 대상으로 인터넷 프로그램을 활용하여 4교시 수업일과 6교시 수업일의 활동별 소비시간을 조사하였다. 활동의 종류는 학내활동과 학외활동으로 구분하고, 학외활동은 학습, 휴식, 여가, 통학, 가사, 생리 활동으로 구분하였다. 총에너지소비량은 4교시 수업일 2300㎉, 6교시 수업일 2230㎉로 조사되었으며, 1일 평균활동계수는 각각 1.73, 1.67로, 6교시 수업일이 4교시 수업일보다 낮았다. 학교에서의 수업시간이 길어지면 여가활동의 시간 및 소비 에너지가 가장 많이 감소하는 것으로 나타났다. 학내활동의 활동 강도는 평균활동계수(PAL)가 1.8 가량으로 저강도 활동(PAL = 2.0～2.9)에 미치지 못하는 것으로 확인되었다. 활동실태를 4단계 활동수준으로 분류하였을 때, 조사 대상 학생의 35% 가량은 저활동적 단계, 40% 가량은 활동적 단계로 밝혀졌다. 총에너지소비량은 6학년이 5학년보다, 남자가 여자보다 많았으며, 과체중 및 비만, 정상, 저체중 집단의 순으로 나타났다. 학외활동 가운데 학습활동과 가사활동의 소비 에너지는 학년별, 성별, 비만도 집단별 차이가 없었으며, 휴식활동과 여가활동의 소비 에너지는 학년별 차이는 없고, 성별, 비만도 집단별 차이는 있었다.