부하를 고려한 태양열온수시스템의 일간 집열효율에 대한 실험적 분석

이경호(Lee Kyoung-Ho),주홍진(Joo Hong-Jin),윤응상(Yoon Eung-Sang),곽희열(Kwak Hee-Youl) 한국태양에너지학회 2012 한국태양에너지학회 논문집 Vol.32 No.2

This paper describes an experimental study on efficiency of solar collector in solar water heating system connected to hourly water heating load. In general, the functional form of solar efficiency is expressed as a function of fluid temperature entering solar collector, ambient temperature, and solar irradiance. When energy saving from solar heating of water heating system is analyzed on a long-term basis such as one year with given solar irradiance data, simplified analysis is more convenient than detailed system simulation for quick assessment. However, the functional form of the efficiency is not convenient for approximately simplified energy analysis because the inlet temperature can be obtained through a detailed system simulation. In the study, solar collector efficiency is obtained with various daily water heating loads and daily solar irradiance using experimental tests. The study also considers large residential buildings such as apartment buildings for application of solar water heating systems. From test results, it is found that daily solar collector efficiency is proportional to daily water heating loads and daily solar irradiance. The data obtained from the study can be utilized to find a functional relation between daily solar irradiance and daily heating load instead of collector inlet temperature for application of solar collector efficiency to long-term approximated energy analysis of solar heating system.

상부 코일히터를 갖춘 나선재킷형 태양열 축열조의 성능예측을 위한 CFD 해석모델 개발 및 검증

백승만(Seung Man Baek),종일명(Yiming Zhong),남진현(Jin Hyun Nam),정재동(Jae Dong Chung),홍희기(Hiki Hong) 대한기계학회 2013 大韓機械學會論文集B Vol.37 No.4

태양열 온수급탕 시스템에서는 태양열 에너지가 집열판에서 획득되고 열매체로 전달되어 최종적으로 온수의 형태로 축열조에 저장된다. 본 연구에서는 상부 코일히터를 갖춘 나선재킷형 축열조의 축열성능 특성을 정확하게 해석할 수 있는 전산유체역학 모델을 개발하였다. 본 연구에서 고려한 축열조는 벽면에 열매체의 나선유로가 형성된 맨틀형 축열조의 일종으로 시스템 설계 단순화, 저유량 운전, 성층화 촉진 등의 장점을 지닌다. 또한 축열조 내부에 추가적인 코일히터가 장착되어 축열성능과 성층화의 추가적인 향상을 도모할 수 있다. 본 연구에서 개발된 해석모델의 검증은 실제 태양열 온수급탕 시스템의 실증실험 결과와 비교를 통하여 수행되었으며, 온수의 온도변화, 열매체의 온도변화, 성층화 온도분포의 측면에서 잘 일치하는 결과를 얻었다. In a solar domestic hot water (SDHW) system, solar energy is collected using collector panels, transferred to a circulating heat transfer fluid (brine), and eventually stored in a thermal storage tank (TST) as hot water. In this study, a computational fluid dynamics (CFD) model was developed to predict the solar thermal energy storage in a hybridtype TST equipped with a helical jacket heater (mantle heat exchanger) and an immersed spiral coil heater. The helical jacket heater, which is the brine flow path attached to the side wall of a TST, has advantages including simple system design, low brine flow rate, and enhanced thermal stratification. In addition, the spiral coil heater further enhances the thermal performance and thermal stratification of the TST. The developed model was validated by the good agreement between the CFD results and the experimental results performed with the hybrid-type TST in SDHW settings.

온수 급탕 및 난방을 위한 히트 펌프 태양열 시스템의 성능 분석

손진국(Sohn Jin-Gug) 한국태양에너지학회 2018 한국태양에너지학회 논문집 Vol.38 No.5

This study aims to analyze the performance of solar thermal system with heat pump for domestic hot water and heat supply. There are four types of system. Systems are categorized based on the existence of a heat pump and the ways of controlling the working fluid circulating from the collector. Working fluid is controlled by either temperature level (categorized as system 1 and 2) or sequential flow (system 3 and 4). Heat balance of the system, the solar fraction, hot water and heating supply rates, and performance of heat pump are analyzed using TRNSYS and TESS component programs. Technical specifications of the main facilities are as follow; the area of the collector to 25 ㎡, the volumes of the main tank and the buffer tank to 0.5 ㎥ and 0.8 ㎥, respectively. Heating capacity of the heat pump in the heating mode is set to 30,000 kJ / hr. Hot water supply set 65 liters per person each day, total heat transfer coefficient of the building to 1,500 kJ / kg.K. Indoor temperature is kept steadily around 22℃. The results are as follows; 6 months average solar fraction of system 1 turns out to be 39%, which is 6.7% higher than system 2 without the heat pump, indicating a 25% increase of solar fraction compared to that of system 2. In addition, the solar fraction of system 1 is 2% higher than that of system 3. Hot water and heating supply rate of system 1 are 93% and 35%, respectively. Considering the heat balance of the system, higher heat efficiency, and solar fraction, as whole, it can be concluded that system 1 is the most suitable system for hot water and heat supply.

공동주택의 제로카본 그린홈을 위한 신재생에너지 하이브리드 열공급 시스템의 열성능 분석

주홍진(Joo Hong-Jin),이경호(Lee Kyoung-Ho),곽희열(Kwak Hee-Youl) 한국태양에너지학회 2012 한국태양에너지학회 학술대회논문집 Vol.2012 No.3

This study was carried out to evaluate thermal performance of the renewable hybrid heat supply system with solar thermal system and wood pellet boiler for Zero Carbon Green home of apartment houses. The hybrid heat supply system was set up at Korea Institute Energy Research in 2011. The system was comprised of the wood pellet boiler unit with heat capacity designed as 20,000 kacal/hr, a evacuated tubular solar collector 3.74 m2 of aperture area at the 20º install angle, a 0.3 m2 hot water storage tank, a 0.15 m2 hot water storage tank for space heating. Thermal performance tests for one-house of apartment house were carried out by hot water load and heating load in winter season through the hybrid heat supply system. As a result, hot water energy supplied by the hybrid heat supply system was 11kWh in a day. Solar thermal energy portion was 2.99kWh which is 27% of the total hot water energy supply, wood pellet boiler supply portion was 8.017kWh which is 73% of the total hot water energy supply.

에너지공유 커뮤니티 구현을 위한 중앙온수급탕 방식의 신재생 열에너지 시스템 적용성 분석

김민휘,이동원,안영섭,주홍진 대한설비공학회 2020 설비공학 논문집 Vol.32 No.11

본 연구에서는 저탄소 에너지공유 커뮤니티 구현을 위한 에너지절감 및 효율개선 방안으로 다양한 신재생열에너지 시스템을 적용한 지열원 급탕 공급시스템을 제안하고, 제안된 시스템에 대한 에너지 절감효과를 분석하였다. 본 시스템을 커뮤니티 시설의 지붕에 설치될 경우 동일 면적에 적용된 경우의 에너지 효율 및 자가소비율에 대해서 분석하였다. 그 결과, ST시스템은 전체 연간 급탕에너지 요구량의 29.6%, PVT 시스템은 10.0%를 담당할 수 있는 것으로 나타났다. PVT 시스템을 적용하는 방식은 PV 시스템 대비 19.1% 낮은 발전량을 나타내었는데, 이는 PVT시스템 발전 모듈의 효율이 낮은 측면과, 비교적 겨울철 높은 온도를 유지하였기 때문으로 나타났다. 하지만, PVT시스템이 적용된 방식에서는 급탕에너지 요구량의 절감으로, PV 시스템과 ST 시스템을 적용하는 방식 대비 각각 22.0%와 37.2%의 운영에너지 절감효과를 가질 수 있는 것으로 나타났다. 반면, 전력의 커뮤니티 단위 자가소비율은 축열조의 사이즈에 따라 사이즈가 작을수록 ST 시스템을 적용하는 방식이 우수하며, 사이즈가 커질수록, PV 시스템을 적용하는 방식이 가장 높은 것을 확인할 수 있었다. 탄소배출저감 효과 또한, 본 제안된 시스템이 기존 시스템 대비 87% 이상의 효과를 얻을 것으로 예측되었다. 본 연구는 태양광 및 태양열 시스템의 성능을 비교적 정확하게 예측하는 TRNSYS 소프트웨어를 사용하여 시뮬레이션을 진행하였으나, 시뮬레이션 연구에 대한 한계가 있으며 결과에 대한 오차가 있다. In this study, a domestic hot water supply system using renewable heat energy systems was proposed for improving energy efficiency and savings to achieve a low-carbon energy sharing community. A smart village in Busan Eco Delta Smart City was selected for this analysis via detailed simulation. This smart village comprises 56 single-family houses and community facilities with a central mechanical center to supply heating, cooling and domestic hot water. In this study, the major thermal energy for domestic hot water is a geothermal heat pump, and applicability of solar energy, such as a photovoltaic (PV) system (Case 1), a solar thermal (ST) system (Case 2), and a photovoltaic and solar thermal (PVT) system (Case 3) was analyzed. As a result of this analysis, it was found that the ST system can account for 30.0% of the annual domestic hot water demand, and the PVT system can account for 10.0%. The PVT system showed 19.1% lower electric generation rates compared with the PV system. However, it was also found that the PVT system can reduce 22.0% and 37.2% of operating energy compared to the PV and ST system, respectively. The PVT can save the thermal demand of domestic hot water even the lower efficiency of PV generation rates. Conversely, it was observed that the PV and ST system showed higher self-sufficiency for the electric energy balance on the community compared to the PVT system depending on the size of the thermal energy storage.

공동주택의 제로카본 그린홈을 위한 신재생에너지 하이브리드 열공급 시스템의 난방 및 급탕 열성능 분석

주홍진(Hong-Jin Joo),이경호(Kyoung-Ho Lee),곽희열(Hee-Youl Kwak) 대한설비공학회 2012 대한설비공학회 학술발표대회논문집 Vol.2012 No.6

제로카본 그린홈 구현을 위한 하이브리드 열공급 시스템의 열성능 분석

주홍진(Joo, Hong-Jin),이경호(Lee, Kyoung-Ho),곽희열(Kwak, Hee-Youl) 한국태양에너지학회 2012 한국태양에너지학회 논문집 Vol.32 No.6

This study was carried out to evaluate thermal performance of the renewable hybrid heat supply system with solar thermal system and wood pellet boiler for Zero Carbon Green home of apartment houses. The hybrid heat supply system was set up at Korea Institute Energy Research in 2011.The system was comprised of the wood pellet boiler unit with heat capacity designed as 20,000kcal/hr, a 0.15㎥ hot water storage tank for space heating, a evacuated tubular solar collector 3.74 ㎡ of aperture area at the 20° install angle, a 0.3 ㎥ hot water storage tank. Thermal performance tests for one-house of apartment house were carried out by hot water load and heating load in winter season through the hybrid heat supply system. As are sult, hot water energy supplied by the hybrid heat supply system was11kWh in a day. Solar thermalen ergy porti on was 2.99kWh which is 27% of the total hot water energy supply. wood pellet boiler supply portion was 8.017kWh which is 73% of the total hot water energy supply.

지역별 기상조건과 급수온도에 따른 태양열 온수공급 시스템 성능에 관한 연구

손진국 한국태양에너지학회 2019 한국태양에너지학회 논문집 Vol.39 No.6

The purpose of this study is to analyze the performance of solar thermal system according to regional weather conditions and feedwater temperature. The performance analysis of the system was carried out for the annual and winter periods in terms of solar fraction, collector efficiency and it’s optimal degree. The system is simulated using TRNSYS program for 6 cities, Seoul, Incheon, Gangneung, Mokpo, Gwangju, and Ulsan. Simulation results prove that the solar fraction of the system varies greatly from region to region, depending on weather conditions and feedwater temperatures. Monthly average solar fraction for winter season from November to February, a time when heat energy is most required, indicated that the highest is 73.6% in Gangnueng and the lowest is 56.9% in Seoul. This is about 30% relative difference between the two cities. On the other hand, the collector efficiency of the system for all six cities was analyzed in the range between 40% and 42%, indicating small difference compare to the solar fraction. The annual average solar fraction is rated the highest at 40 collector degree, while monthly average solar fraction during winter season is rated at 60 degree.

태양열 냉난방 시스템의 중간기 급탕 실증실험 및 분석

이은주(Eun-Ju Lee),강기남(Kinam Kang),남현민(Hyun-min Nam),이동규(Dong Kyu Lee),이병두(Byoungdoo Lee) 대한설비공학회 2017 대한설비공학회 학술발표대회논문집 Vol.2017 No.6

직팽식 태양열 히트펌프 시스템을 활용한 소규모 분산형 열에너지 프로슈머의 적용 가능성 분석

김민휘(Minhwi Kim),김득원(Deukwon Kim),이동원(Dongwon Lee),허재혁(Jaehyeok Heo) 한국태양에너지학회 2020 한국태양에너지학회 학술대회논문집 Vol.2020 No.10