• 한국태양에너지학회:학술대회논문집
• /
• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
• /
• pp.250-255
• /
• 2009

This study was analyzed the long term performance of the demonstration system for solar energy desalination in Jeju. we used a solar thermal system as heat source of the single-stage fresh water generator with plate-type heat exchangers and a photovoltaic power system as electric source for hydraulic pumps. The demonstration system was designed and installed at Jeju-island in 2006. The system was comprised of the desalination unit with daily fresh water capacity designed as $2m^3$ a $120m^2$ evacuated tubular solar collector to supply the heat, a $6m^3$ heat storage tank, and a 5kW photovoltaic power generation to supply the electricity of hydraulic pumps for the heat medium fluids. Through the operation during about 3 years, In a clear day more than $400W/m^2$, the daily fresh water showed to produce more than about 500liter, and from January, 2007 to March, 2009 for 3 years, solar irradiance daily averaged was measured $370W/m^2$, the daily fresh water yield showed that can be produced about 330liter.

• 한국농공학회논문집
• /
• 제46권7호
• /
• pp.71-80
• /
• 2004

A system for estimating daily paddy irrigation water requirements was developed to simulate daily stream flows that reflect various upstream and downstream return flows from river basin. Evapotranspiration in paddy fields was estimated using the modified Penman equation. Daily irrigation water requirements of paddy fields were calculated by multiplying the paddy area and the daily decrease in ponding depth. The system was constructed almost completely using images, grids, etc. in Visual Basic 6.0. The developed model was verified in the Damyang dam, and was used to estimate daily paddy irrigation water requirements at 12 small watersheds in Geum river basin for 20 years, from 1983 to 2002, covering paddy field areas of $3,332\~26,422$ ha. The results on the runoff analysis on the inflow to the Daecheong multi-purpose dam with various return flows were satisfactory. They were reasonable compared to the scenario where return flows were not considered.

• 디지털융복합연구
• /
• 제16권7호
• /
• pp.1-8
• /
• 2018

우리나라는 성공적인 물 관리를 위하여 1980년대 이후 상수도 보급을 중심으로 한 공급정책이 성공적으로 진행되었고, 1990년대 이후 물 가격이 상수도 수요에 미치는 영향 등 수요관리에 대한 정책이 이어지고 있다. 최근 들어 물 가격결정과 효율적인 수자원 관리에 논의가 부각되고 있다. 본 논문은 부산지역을 대상으로 물수요 관리의 핵심 변수로서 물 가격의 결정 요인과 가격 수준 설정에 대한 논의를 수요함수추정을 통하여 분석한다. 주요 변수로는 총 인구, 수도 요금, 소득, 가구 수, 에너지 가격으로 선정되었고, 시계열 자료의 특성을 고려한 초월대수함수 모형을 설정하여 분석하였다. 분석결과에 따르면 물 수요는 인구, 소득 등 실물 경제변수에는 양의 효과를, 물 가격, 에너지 가격 등 가격변수에는 음의 효과를 나타냈다. 향후 지역별 미래 물 소비량에 따른 공급 능력 확보와 지속적인 물 절약을 위하여 수도 요금 조정이 효율적 정책방안으로 판단되며, 디지털 정보의 이용 확대 등 보완적 수자원 관리 정책도 동시에 요구된다. 또한 용도별, 지역별, 시간별로 세분화된 자료를 구축하고, 정교한 계량분석모형을 이용한 연구가 요청된다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.1964-1968
• /
• 2007

The river water heat source heat pump has the advantage in the performance compared to air source heat pump. Although its better performance, the large temperature difference between load and source makes system performance worse by nature. In this study, 2-stage compression is considered as the solution of this problem. Generally, heat pump is designed for maximum capacity rate, but it actually operates at part load condition in many cases. Therefore, an information on the part-load character is very important in view of the system overall performance. In this study, part-load performance tests of a R134a 2-stage compression heat pump were carried out over the river water and supply heating water temperature changes. The experimental results show that the system performance is influenced by the part load rates, river water temperature, load temperature, etc.

• 한국지열·수열에너지학회논문집
• /
• 제5권1호
• /
• pp.13-17
• /
• 2009

The river water heat source heat pump has the advantage in the performance compared to air source heat pump. In this study, an experimental study on a 2-stage heat pump, which is designed to utilize a river water heat source, were carried out. Generally, a heat pump is designed for maximum capacity rate, but it actually operates at part load condition in most cases. Therefore, an information on the part-load characteristic is very important in view of the system overall performance. In this study, part-load performance tests of a R134a 2-stage compression heat pump were carried out over the river water and supply heating water temperature changes.

• 한국태양에너지학회 논문집
• /
• 제27권3호
• /
• pp.55-61
• /
• 2007

This paper has been conducted to estimate cooling capacity of the dehumidification tower using hot water from a solar water heating system as a energy source of regeneration process when the dehumidification and drying system is applied to room cooling. A solar water heating system was operated and indoor temperature distributions were simulated according to weather conditions when the concerned solution was used to dehumidify room air in the dehumidification tower. Through this simulation researches we found th following results ; It was found that air velocity through supply and return diffusers should be controlled because it can cause uncomfort in dwelling area. It was found that in the sunny morning temperatures of dwelling area 1 and 2 are higher than those of dwelling area 3 and 4. In this research all the calculation results of heating and cooling system supported by solar water heater have confirmed that its cooling capacity could not reach PMV 0, thermal comfort.

• 대한환경공학회지
• /
• 제36권5호
• /
• pp.333-341
• /
• 2014

본 연구에서는 양도 초등학교에 강우량과 집수면적, LPCD를 고려하여 빗물이용시설을 설치하였다. 빗물이용시설은 학교 내 외의 상수를 대체하고자 하는 목적으로 설계되었다. 용량은 2톤으로 학교 용수의 34.4%를 대체할 수 있었으며 1년의 2/3정도인 237일 동안 빗물을 사용할 수 있었다. 총 세 차례의 수질검사 결과 일반 세균을 제외한 나머지는 먹는 물 수질에 적합하였다. 또한 동시간에 조사한 주변 지하수는 일반세균을 비롯한 질산성질소, 증발잔류물이 기준치를 초과하였다. 빗물의 수질 및 수량을 고려한 결과, 양도초등학교의 경우 빗물을 대체용수로서 사용하기에 적합하였다. 빗물시설에 대한 경제성 분석 결과, 내구연수 10년인 빗물이용시설은 B/C (Benefit-Cost Ratio) 비율이 1.70으로 경제성 편익이 비용보다 큰 걸로 나타났다. 특히 본 연구에서 고려한 사회적인 요인 외에도 금액으로 환산하기 힘든 홍수방지, 가뭄대비, 교육 효과가 있어 사회적 편익이 더욱 증가할 것으로 예상된다.

• 한국수자원학회논문집
• /
• 제55권12호
• /
• pp.999-1009
• /
• 2022

춘천 물로리 지역은 지방상수도가 보급되지 않은 물복지 소외지역으로 복류수 및 지하수를 수원으로 하는 소규모 급수시설로 마을에 물을 공급하고 있다. 가뭄시 물부족 문제를 해결하고 증가하는 물수요에 대비하기 위해 계곡에 연하여 샌드댐을 설치하였으며, 2022년 5월부터 이 시설을 운영하고 있다. 본 연구에서는 과거 가뭄시 샌드댐이 있을 경우의 물공급 신뢰도를 평가하기 위해 MODFLOW모형을 이용한 지하수유출량 모의결과를 활용하여 미계측 기간인 2011년부터 2020년까지의 유입량 자료를 생성하였다. 기존 취수원과 샌드댐이 위치한 곳의 상류부 유역에 대해 SWAT-K 유역수문모델링을 수행하여 지하수유출량을 산정하고, 2021년 월별 지하수유출량에 대한 그 이전 10년 동안의 각 월별 지하수유출량의 상대적 비율을 구한 후 2021년 유입량 시계열 자료에 이 비율을 적용하여 2011년부터 2020년까지의 과거 유입량 자료를 생성하였다. 수요량 20 m³/일, 50 m³/일, 100 m³/일 세 가지 경우에 대해 과거 극한 가뭄시의 물공급 가능여부를 분석한 결과, 샌드댐 설치로 물공급 신뢰도가 증가하는 것을 확인 할 수 있으며, 수요량 100 m³/일인 경우에는 기존 취수원과 샌드댐을 연계 운영해야만 신뢰도 90%를 넘는 것으로 분석되었다. 세 가지 운영조건 모두 물공급 신뢰도 95%를 기준으로는 수요량 50 m³/일 이상, 신뢰도 99%를 기준으로는 수요량 30 m³/일 이상을 만족하는 것으로 평가되었다.

• 동력기계공학회지
• /
• 제21권6호
• /
• pp.79-85
• /
• 2017

A heat pump system is a highly efficient, eco-friendly device which consumes a small amount of energy and supply a lot of energy for heat formation. In addition, it is a single device system that has low generation effect about carbon dioxide. There are many researches related to the electronic expansion valve and the heat pump, but the detailed data analysis of each influence is insufficient. In this study, the cooling capacity and COP of the heat pump system were investigated by varying frequency of the inverter connected to compressor, inlet temperature of chilled water into evaporator and inlet temperature of cooling water into condenser. The results are as follows : (1) The cooling capacity increased as the inverter frequency, inlet temperature of chilled water into evaporator increased, and inlet temperature of cooling water into condenser decreased. (2) The COP increased as the frequency of inverter, inlet temperature of cooling water into condenser decreased and the inlet temperature of chilled water into evaporator increased.

• 한국농공학회논문집
• /
• 제55권3호
• /
• pp.13-24
• /
• 2013

Agriculture is affected directly by climate conditions and changes, and it is necessary to understand the impact of climate change on agricultural reservoirs which are the main water resources for paddy fields in Korea. This study aimed to evaluate the impact of climate change on the anti-drought capacity including water supply capability (WSC) and drought response ability (DRA) of agricultural reservoirs based on RCP (Representative Concentration Pathway) 4.5 and 8.5 scenarios of CanESM2 (The Second Generation Earth System Model) provided by CCCma (Canadian Center for Climate Modeling and Analysis). The WSC and DRA were estimated using frequency analysis and runs theory. The six reservoirs (Yooshin, Nogok, Kumsung, Songgok, Gapyung, Seoma) were selected considering geographical characteristics and design criteria of reservoir capacity. In case of Seoma reservoir, more than 10 year drought return period (DRP), the variation of the WSC was estimated larger than the others. In case of Yooshin reservior (2~5 DRP) DRC was decreased in 2025s under RCP8.5. These results could be utilized for agricultural reservoirs management and future design criteria considering climate change impacts on paddy irrigation.