• 한국농공학회논문집
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• 제53권6호
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• pp.145-152
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• 2011

In order to heat greenhouse nearby river channel, riverbank filtration water source heat pump was developed for getting plenty of heat flux from geothermal energy. Recharging well, thermal storage tank with separating insulation plate and filtering tank for eliminating iron, manganese were mainly developed for making the coefficient of performance (COP) of heat pump higher. Heating system using riverbank filtration water source heat pump was installed at a paprika greenhouse in the Jinju region where a single fold of vinyl cover and 2 layers of horizontal thermal curtain were installed as a part of temperature keeping and heat insulation with a greenhouse area of 3,185 $m^2$. 320,000 kcal/h was supplied for performing a site application tests. A greenhouse heating test was performed from Feb. 1, 2011 to Apr. 30, 2011. As the result of that, COPh of the heat pump was measured in the range of 4.0~4.5, while COPS of the system was represented as 2.9~3.3. COP measured of the heat pump was very good and well responded to indoor heating temperature of the environment control system of a greenhouse.

• 대한기계학회논문집B
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• 제34권9호
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• pp.875-883
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• 2010

본 연구에서 차량 탑재용 LNG 연료 탱크의 단열 성능과 연료 공급 능력 등을 예측하기 위하여, 내조와 외조 사이가 진공 단열된 2중 벽 구조이며 탱크 용량은 450$\ell$, 정상 운전조건은 800 kPa인 연료 탱크를 해석 대상으로 선택했으며, LNG의 물성치는 메탄($CH_4$)과 동일하다고 가정했다. 밀폐 저장기간의 연장을 위하여, 차폐 관을 제시했고 기존의 연료 탱크 저장 기간과 비교 해석했다. 또한 기관으로의 적절한 연료량 공급을 보장할 수 있는 탱크 내의 압력 유지를 위하여, 외부로부터 추가적인 열전달률을 예측했다. 이러한 계산을 위하여 압력 변화율과 전열률, 연료 출입률 간의 열역학 관계식을 유도했고, 선택한 연료 탱크 모델로부터 열저항을 근거한 계산식을 설정했다. 계산 결과에 의하면, 차폐된 관을 사용한 연료 탱크는 약 25~30% 이상의 저장기간이 연장되었고, 연료 압송 최소압력 유지를 위하여 외부에서 탱크로 공급되는 열전달에 적합한 운전조건도 결정할 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.172.2-172.2
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• 2010

This study was carried out in order to reduce the installation expense of heating system for greenhouse comparing to geothermal heat pump and develope the coefficient of performance (COP) for a heat pump. For getting plenty of heat flux from geothermal energy. Surface water in river channel was used for getting a lots of geothermal heat by penetrating water through underground soil layer of the river bank that make heat transmission to passing water. The range of water temperature after the process of Ground filtration is 13~18 degrees celsius which is very similar to low heat source of geothermal heat pump system and the plenty amount of heat source from that make the number of geothermal heat exchanging hole and the expense for geothermal heat exchanger construction reduced. Drainage well is also used for returning filtration water to the aquifer that keep the water good recirculation from losing geothermal heat and water resource. For the COP improvement of Heat pump, thermal storage tank with separating insulation plate according to the temperature difference make the COP of Heat pump that is similar to thermal storage tank with diffuser. Developed thermal storage tank make construction expense cheaper than customarily used one's. and that sand filter and oxidation sand (FELOX) are going to be used for improving ground filtration water quality that make heat exchanger efficiency better. All above developed component skill are going to be set on the Ground filtration water source heat pump system and applied for medium, large scale for protected greenhouse in riverside area and on-site experiment is going to do for optimizing the heating system function and overcome the problem happening in the process of on-site application afterward.

• 한국태양에너지학회 논문집
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• 제27권3호
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• pp.45-54
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• 2007

For a conventional natural-circulation type solar water heater, the pressure head is limited by the height between the storage tank and hot water tap. Therefore, it is difficult to provide sufficient hot water flow rate for general usage. This study deals with a design modification of the storage tank to utilize the tap-water pressure to increase hot-water supply Based on fluid dynamic and heat transfer theories, a series of modeling and simulation is conducted to achieve practical design requirements. An experimental setup is built and tested and the results are compared with theoretical simulation model. The storage tank capacity is 240 l and the outer diameter of piping was 15 mm. Number of tube turns tested are 5, 10, and 15. Starting with initial storage tank temperature of $80^{\circ}C$, the temperature variation of the supply hot water is investigated against time, while maintaining minimum flow rate of 10 1/min. Typical results show that the hot water supply of minimum $30^{\circ}C$ can be maintained for 34 min with tap-water supply pressure of 2.5 atm, The relative errors between modeling and experiments coincide well within 10% in most cases.

• 한국태양에너지학회 논문집
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• 제32권5호
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• pp.11-17
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• 2012

In this study, a simulation program was developed with heat transfer model in the thermal storage tank for a solar collector and burner combined heating and hot water supply system. Analysis was conducted with variation of operating condition and schedule to analyze performance of a hot water supply and panel heating system with a solar collector and burner combined thermal storage tank. The simulation program is divided two sections. One part is calculation of temperature variation of water which flows through the panel in the floor for heating of the residential house during 24 hours, and the other part is heat transfer calculation for the reaction time to get desired water temperature in the thermal storage tank. As results, light oil consumption and system performance during operation period were analyzed with variation of climate condition and with or without solar collector. Most of the case, oil could be saved about from 24 to 41% with installing the solar collector. The performance of the system is more dependent on radiation time of the solar collector rather than the intensity of the solar radiation which was adopted for the climate analysis.

• 태양에너지
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• 제14권2호
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• pp.3-16
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• 1994

축열조에 대한 연구에서 유입되는 유입수와 초기 저장수와의 사이에 필연적으로 일어나는 혼합 현상을 최대로 억제함으로서 열성층을 형성시켜야 한다. 열성층을 지배하는 인자로는 각종 동적, 기하학적 인자 등이 있다. 동적 인자는 유입 유동율이며 기하학적 인자로는 유출입구 형상이다. 출구 온도를 이용하여 축열조 내의 열성층 정도를 파악할 수 있는 새로운 개념의 성층도를 제시하였고 동적 인자와 더불어 열성층에 영향을 미치는 여러 지배 물성치들을 차원 해석하여 적절한 무차원 형태로 단순화 시켜 얻어진 Peclet수, Richardson수와 성층도의 관계를 확립함으로써 가장 안정된 열성층을 얻을 수 있는 동적 임계 조건을 밝혔다.

• 스마트미디어저널
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• 제12권10호
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• pp.63-70
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• 2023

최근 스마트팜 에너지 비용 중 35% 낸난방비 에너지 소비가 증가되어 에너지 소비 효율화가 요구되며, 전기료 현실화에 대한 우려로 신재생 에너지 중요성이 증가하고 있다. 신재생 에너지는 수력, 풍력, 태양광 등에 속하며, 이중 태양광 에너지는 전기에너지로 변환하는 발전기술로, 이 기술은 에너지원이 환경에 미치는 영향이 적고, 유지 보수가 간편하다는 특징을 갖고 있다. 본 연구에서는 온실 축열조, 히트펌프 데이터 기반으로 축열조 영향을 많이 미치는 요소를 선정하고 축열조 공급 온도예측 모델을 개발하고자 한다. 시계열 데이터 분석 및 예측에 효과적인 LSTM(Long Short-Term Memory)과 다른 앙상블 학습 기법보다 뛰어난 XGBoost 모델을 이용하여 예측한다. 히트펌프 축열조 온도를 예측함으로써 에너지 소비를 최적화하여 시스템 운영을 최적화할 수 있다. 또한, 태양광 활용에 따른 냉난방비 절감 및 농가의 에너지 자립도 개선 등 스마트팜 에너지 통합 운영 시스템에 연계하고자 한다. 플랫폼을 통해 폐열 에너지의 공급을 관리하고 최대 난방부하 및 계절, 시간별 작물생장에 필요한 에너지값을 도출하여 이를 기반으로 최적 에너지 운용방안을 도출하고자 한다.

• 한국태양에너지학회 논문집
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• 제21권1호
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• pp.61-69
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• 2001

The heat transfer characteristics of horizontal and vertical mantle heat storage tanks are studied in order to replace the tank-coil heat exchanger for application in thermosyphon solar water heaters. In this study, 5 mantle storage tanks with different geometric shape are manufactured into stainless steel and each tank is tested. For the test, The inlet flow rate of the heat transfer fluid is maintained 1.2 lpm consistently. The heat transfer fluid temperature through the mantle is $70{\pm}1^{\circ}C$. The temperatures of 26 points included the ambient temperature are measured at every one minute. The measured data are used to calculate the overall heat transfer coefficient(UA) using the LMTD(Log Mean Temperature Difference) method and it is used on the analysis of the heat transfer characteristics to search for optimum arrangement.

• 태양에너지
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• 제19권2호
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• pp.1-8
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• 1999

The heat transfer characteristics of ice storage system of falling film type using sprial coil is investigated. The experimental facilities consisted of a water tank, spiral coils located above the tank, an upper water distributor, and a circulating water pump. Water is distributed uniformally over the spiral coils and it forms falling thin films. In the process of freezing, ice is formed on outside of the spiral coils through recirculation of tank water. In the process of melting, ice is melted with return water from the heat load, while the water is chilled again and drops into the tank. The results of falling film type of ice thermal storage system are as follows. The highly efficient shower flowrates for icing is near $3{\ell}/min$. Icing rates on spiral coils is rosed while brine flowrates is increased. Lower brine temperature is not only increased freezing rates but. also become higher total icing weight and overall heat transfer coefficient. Smaller shower flowrates is obtained lower water temperature on outlet for a long time. The amounts of quantity can be detected more accurately by measuring storage tank weight.

• Journal of Biosystems Engineering
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• 제31권3호
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• pp.161-167
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• 2006

The purpose of this study is to find the optimal conditions of PCM slurry manufacturing equipment for saving the marketing cost and keeping the original quality of products. In addition, the characteristics of the movable container for shipping or distributing products is analysed. The major results are as follows. 1. PCM thermal storage system is designed with the conditions of temperature($-5{\sim}10^{\circ}C$), cold chain time(30 minutes), and one time usage(50 liter). This system includes tank, freezer, circulating pump, cycle type heat exchanger, swelling tank, equipment of supplying PCM supplying unit includes cold tank, cycle type heat exchanger, suction unit and control equipments, etc. 2. After ability test of PCM thermal storage system, it shows that the required freezing time of PCM thermal storage system is less than one of the previous system. The reason is that churn (top and bottom) and compulsion circulation are occurred simultaneously and unit cooler type method is better than chiller type method. 3. By the experiment of transportation latent heat container, it is decided that the best container is $K_1$ with latent heat temperature($0{\sim}5^{\circ}C$) and density(0.15%). However, for $K_l\;and\;K_2$, it is necessary more studies on latent heat thermal conditions and conditions of making method.