수경온실의 양액랭각에 관한 연구

목차

국문초록
목 차
List of Tables
List of Figures
1. 서 논
1.1 연구배경 및 목적
1.2 연구사
1.2.1 하절기 온실의 환경특성
1.2.2 온실의 냉방 및 냉각 관련 모델 연구
1.2.3 수경온실의 양액 냉각 관련 연구
2. 수경재배 시스템의 전열특성
2.1 열전달 특성식
2.2 실험장치 및 방법
2.3 전열특성 및 양액랭각 효과
2.3.1 양액의 전열특성
2.3.2 작물의 전열특성
2.3.3 양액 냉각의 효과
3. 냉각부하 산정을 위한 수치모델의 개발
3.1 모델의 개발
3.1.1 온실의 일사량 분석
3.1.2 수경온실의 열 및 물질평형식의 구성
3.1.3 열 및 물질평형식 구성인자의 분석
3.1.4 시뮬레이션 모델의 구축

3.2 모델의 검증
3.2.1 모델의 검증 방법
3.2.2 모델의 검증 결과
3.3 수경온실의 설계용 양액랭각부하
3.3.1 양액랭각부하에 영향을 미치는 주요인자
3.3.2 설계용 기상자료
3.3.3 수경온실의 양액랭각부하
4. 이중관식 역대류형 양액랭각시스템의 개발
4.1 양액랭각에 관한 기초실험
4.1.1 실험장치의 구성 및 측정방법
4.1.2 튜브를 통한 열교환 특성
4.1.3 냉각 성능 검토
4.2 양액랭각시스템의 개발
4.2.1 냉각시스템의 구조
4.2.2 냉각시스템의 열교환 특성
4.3 냉각시스템의 성능평가 및 적용성 검토
5. 요약 및 결론
장래 연구를 위한 제언

본문내용

icult to expect the normal production of plants in greenhouses during hot summer season in Korea, certain provisions on the control of extreme environmental factors in summer should be considered for the year-round cultivation in greenhouses.
This study was carried out to find a means to suppress the temperature rising of nutrient solution by cooling, which is able to contribute to the improvement of the plant growth environment in hydroponic greenhouse during hot summer season.
The specific objectives to accomplish the above purpose were as follows :
1. To establish a set of heat balance equations to represent the heat transfer characteristics of plant and nutrient solution.
2. To develop a numerical model for prediction of cooling load of nutrient solution.
3. To develop a mechanical cooling system of nutrient solution by using ground water.
For making clear the heat transfer characteristics and the effect of cooling of nutrient solution on the plant temperature in hydroponic culture system, heat balance equations for plant and nutrient solution were theoretically established and experimentally verified. About 96 percent of the total heat flow transferred from culture bed to nutrient solution was proved to be the conductive heat through planting board and partitioning material. The drops in average and maximum temperatures of the leaf lettuce were 0.6℃ and 1.5℃ by cooling of nutrient solution by 6℃, respectively.
A numerical model for prediction of cooling load of nutrient solution in hydroponic greenhouse was developed, and the results by the model showed a good agreement with those by experiments. Using the model developed, design cooling load of nutrient solution in hydroponic greenhouse of 1,000 m2(300 pyong) was predicted to be 95,000 kJ/hr in Suwon and the vicinity.
A mechanical cooling system using the counter flow type with double pipe was developed for cooling the nutrient solution, efficiently. Also the heat transfer characteristics of the system was analysed experimentally and theoretically, and compared with the existing cooling systems of nutrient solution. The cooling capacities of three different systems, which used polyethylene tube in solution tank, stainless tube in solution tank, and the counter flow type with double pipe, were evaluated. The performance of each the cooling system was about 41%, 70% and 81% of design cooling load in hydroponic greenhouse of 1,000m2 on the conditions that the flow rate of ground water was 2m3/hr and the temperature difference between two liquids was 10℃.
From the results analysed as above, the cooling system showed to have a satisfactory cooling capability for regions where the abundant supply of ground water is available. For the other regions where the supply of ground water are restricted, more efficient cooling system should be developed.
Key words : cooling of nutrient solution, cooling load, cooling system,
heat transfer characteristics, numerical model, hydroponic greenhouse

키워드

양액랭각,   냉각부하,   냉각시스템,   냉각 성능 검토,   냉각시스템의 열교환 특성,   냉각시스템의 구조