진공관형 태양열 집열장치의 성능평가 및 해석 연구

전태규,안영철 한국에너지학회 2013 에너지공학 Vol.22 No.2

태양열 에너지는 우리나라의 전체 에너지에서 차지하는 비율은 아직 미미하지만, 근래 이 분야에대한 연구가 활발히 이루어지고 있다. 본 연구는 외부 날씨의 영향을 받지 않고 실내에서 안정적으로태양열집열기에 관한 실험을 수행할 수 있는 태양열집열기 성능검사 시스템을 구축하고 새로운 형태의태양열집열기를 연구·개발하기 위한 기초자료를 얻는데 있다. 이를 위해 태양열집열기 성능검사 시스템에 대한 CATIA 설계 및 제작을 거쳐 성능검사를 실시하였으며, 본 시스템에 장착된 이중진공관집열기에 대한 수치해석을 수행하였다. 실험 결과 태양열집열기 성능검사 시스템의 설정온도차( T)의증가에 따라 작동회수는 감소하지만 총 작동시간은 모든 경우에 거의 동일함을 알 수 있었다. 또한수치해석 결과 태양열흡수부의 온도가 높을수록 집열기 중심에서의 온도 감소율이 증가하는 것을 알수 있었다.

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.

Facade 일체형 태양열 집열기를 갖는 태양열/지열 하이브리드 시스템의 태양열 집열시스템 작동특성 연구

백남춘(Baek Nam-Choon),이진국(Lee Jin-Kook),유창균(Yu Chang-kyun),윤응상(Yoon Eung-Sang),윤종호(Yoon Jong-Ho) 한국태양에너지학회 2010 한국태양에너지학회 논문집 Vol.30 No.5

In this study, the solar thermal and geo-source heat pump(GSHP) hybrid system for heating and cooling of Zero Energy Solar House(ZESH) was analyzed by experiment. The GSHP in this hybrid system works like as aback-up device for solar thermal system. This hybrid system was designed and installed for Zero Energy Solar House (KIER ZeSH) in Korea Institute of Energy Research. The purpose of this study is to find out that this system is optimized and operated normally for the heating load of ZeSH. The analysis was conducted as followings ; -the thermal performance of facade integrated solar collector -the on/off characteristics of solar system and GSHP -the contribution of solar thermal system. -the performance of solar thermal and ground source heat pump system respectively. -the meet of thermal load (space and water heating load). This experimental study could be useful for the optimization of this system as well as its application in house. This hybrid system could be commercialized for the green home if it is developed to a package type.

태양열 실증시스템의 진공관형 태양열 집열기 장기 열성능

이호(Lee Ho),주홍진(Joo Hong-Jin),윤응상(Yoon Eung-Sang),김상진(Kim Sang-Jin),곽희열(Kwak Hee-Youl) 한국태양에너지학회 2008 한국태양에너지학회 학술대회논문집 Vol.- No.-

This paper presents demonstration study results derived through field testing of a part load solar energized cooling system for the library of a cultural center building located in Gwangju, Korea. First operating demonstration system was set up in Gwangju in 2005. These system comprises the 200㎡ evacuated tubular solar collector, a 6㎡ heat storage tank. In a 2003, daily average of insolation showed about 506\/㎡ the solar collector efficiency was 44%. In a 2007, daily average of insolation showed about 507W/㎡ the solar collector efficiency was 42%. As a result, evacuated tubular solar collector kept the high efficiency for two years.

벽체일체형 자연순환 태양열온수기의 동적거동과 열성능에 관한 실증연구

백남춘(Baek Nam-Choon),김성범(Kim Sung-Bum),신우철(Shin U-Cheul) 한국태양에너지학회 2016 한국태양에너지학회 논문집 Vol.36 No.6

In this study, the evaluation of the dynamic behavior and thermal performance of the “Façade integrated Natural circulation Solar Water Heating System” installed in the residential house was carried out. Experimental tests were performed during the all year around in the rural houses of 166 m² in size. Facade integrated solar collector of 5 m² were installed on the south-facing. Electrical heater of 1 kW capacity as an auxiliary heater was installed at the upper part of the heat storage tank. The analyzing results are as follows. (1) Monthly average solar fraction was 51 to 87% and yearly average value is 64%. (2) Hot water supply temperature in December which has the lowest solar altitude is 37 to 76℃. The highest working fluid temperature of solar collector in this period was below 84℃. The temperature difference of working fluid between the collector inlet and outlet has been shown to be around 9 to 26℃. (3) Overheating which is one of the biggest problems during summer did not appear at all, but rather had hot water supply temperature is rather low as 30~47℃ in summer than winter, which is supplied by a small solar load. The solar collecting temperature has been shown to maintain below 55℃. (5) The thermal performance of Facade integrated solar collector can be increase due to the reduction of heat loss to the back of the collector wall integration of the collector is reduced. As a conclusion, Facade integrated natural circulation type Solar Water Heating System is a well-functioning without any pumps or controllers, and it was found that the disadvantages of conventional solar water heaters, hot water or hot water system can be greatly improved.

불활성 가스를 주입한 이중투과체 구조 평판형 태양열집열기의 열성능 비교 분석

이기원(Ki-Won Lee),김정석(Jung-Seok Kim),조성구(Sung-Goo Cho),강병국(Byung-Guk Kang),최준영(Jun-Young Choi) 대한설비공학회 2016 대한설비공학회 학술발표대회논문집 Vol.2016 No.6

Solar energy is quantitatively unlimited clean and non-polluting resource. It has a great potential for industrial and commercial usages. IEA(International Energy Agency) conducted SHC(Solar Heating & Cooling) 33 project in order to use solar thermal energy for industrial processes, and thus, solar thermal collectors for the various temperature zones had been developed. The flat plate solar thermal collector is used primarily for the domestic house, which is currently the most popular with its high durability. Whereas, the evacuated tube-type solar collector is generally used in industrial facility with its high thermal performance, but it has disadvantage in low durability. The double-glazed flat plate solar collector is to overcome the disadvantage of existing single-glazed flat plate solar collector and to improve the durability and the thermal performance. This study has been carried out comparison analysis for thermal performance of single-glazed flat plate solar collector and double-glazed flat plat solar collector with filling air and specified inert gas. And the specified inert gas was injected to the air gap portion of the double-glazed solar collector to improve the thermal performance. As a result, the double-glazed flat plate solar collector with filling specified inert gas has the best performance with comparing to the single-glazed flat plate solar collector and double-glazed flat plat solar collector with filling air. Also, the heat loss coefficient was lower with the specified inert gas than the existing flat plate solar collector.

PTC 태양열 집열기를 이용한 슬러지 열탈수 연구

이정언(Lee Jung-Eun) 한국태양에너지학회 2014 한국태양에너지학회 논문집 Vol.34 No.3

A flat-plate or vacuum tube solar collector have been mainly used for hot water supply of house because of some being difficult to get uniform energy density, so little applied into industrial field. This study is to apply the PTC(parabolic trough collector) solar collector into industrial field such as sludge dewatering system for energy reduction. The real scale system which composed of PTC Solar Collector and Thermal Dewatering (TDW) is established. PTC solar collector is designed to produce a hot water with 80℃ of temperature. And size of TDW is 630×630 mm. Hot water produced from PTC solar collector is supplied into heating plate of TDW, and sludge like waterworks or wastewater is dewatered. PTC solar collector with 10㎡ of area produce energy of average 5,618 kcal. As according to results from real scale performance, solar collector takes charge 94 % of the amount that TDW consume energy which is so large part if compare with boiler. It means that PTC solar collector is useful to apply industrial field under the condition of sufficient solar radiation. And it is analyzed that TDW by PTC solar collector has an economical validity.

CFD를 활용한 태양열 공기가열기 내 사각저항체 설치 조건에 따른 열전달 및 압력강하에 관한 연구

최휘웅,김영복,손창효,윤정인,최광환 한국태양에너지학회 2019 한국태양에너지학회 논문집 Vol.39 No.1

태양열 공기 가열기의 경우 덕트 내 저항체 설치에 따라 성능에 많은 차이를 보이게 된다. 따라서, 이와 관련된 많은 연구가 진행된 바 있으나 제작이 다소 어려운 흡수판에 저항체를 부착하는 방식을 주로 조사되어왔다. 따라서 본 연구에서는 제작이 용이하면서 상대적으로 설치가 쉬운 사각저항체가 태양열 공기 가열기 공기채널 내 설치된 경우 사각저항체 형상 조건에 따른 열전달 및 압력강하 성능을 전산열유체해석을 통해 확인해보고자 하였다. 그 결과, 열전달 성능은 사각저항체 설치 조건에 따라 최소 1.2배에서 최대 3.32배까지 향상되는 것을 확인할 수 있었다. 반면, 열전달 성능 향상과 함께 압력강하 또한 증가하는 모습을 보였고, 최소 2.8배에서 최대 180배까지 그 값이 증가하는 것을 확인할 수 있었다. 따라서 압력강하 증가 대비 열전달 성능 향상 정도에 대한 평가가 필요하며, 이를 위해 본 연구에서는 성능계수를 이용하였다. 성능 계수의 경우 최대 값 0.828정도를 보였으며, 열전달 성능이 향상될수록 해당 값이 적어지는 것을 알 수 있었다. 즉, 사각저항체 설치 및 형상 변경을 통한 열전달 성능 향상에 이보다 더 큰 압력강하 증가가 수반된다는 것을 확인할 수 있었으며, 향후 실제 태양열 공기가열기 적용을 위한 사각저항체 형상 조건 선정 시 필요 열전달 성능 향상 정도와 허용 압력강하에 대한 추가적인 고려가 수반될 필요가 있을 것으로 사료되었다. The solar air heater has various performances according to an obstacle installed in the air duct. Many studies on thermal performance have been conducted. But many of these studies were using a kind of rib type obstacle attached at the bottom of absorbing plate, but they are so hard to be manufactured. In this study, characteristics of the heat transfer and pressure drop in the solar air heater with various horizontal rectangular obstacles was investigated by CFD(Computational Fluid Dynamics) analysis. As a result, the heat transfer performance was improved from 1.2 to 3.32 times depending on installation conditions of rectangular obstacle. The pressure drop, however, also increased with increment of heat transfer performance from 2.8 to 180 times only by changing installation conditions of rectangular obstacle. Thus, the performance factor presenting the thermal performance enhancement on the same pressure drop was also confirmed. As a result, the highest value of 0.828 as better performance factor was obtained at the lower height of rectangular obstacle and this value has started to decrease with increment of heat transfer performance. In the end, it could be confirmed that the pressure drop was carried higher than the quantity of improvement of the heat transfer performance when the heat transfer performance was increased by change of installation conditions of rectangular obstacle. Both heat transfer enhancement and pressure drop to be required for system need to be considered before the rectangular obstacles are applied to the solar air heater.

외기온도 변화에 대한 공기식 태양열 집열기의 열성능 신뢰성 검토 연구

김유진(Kim Yu Jin),왕은석(Wang Eun Seok),이범준(Lee Beom Joon),신형기(Shin Hyung Ki),이의준(Lee Euy Joon),강은철(Kang Eun Chul) 한국태양에너지학회 2021 한국태양에너지학회 논문집 Vol.41 No.3

Solar air collector is a technology that uses the solar radiation heat energy as a heat source for the ventilation and heating of buildings to reduce energy consumption. According to ISO 9806 solar air collector thermal performance evaluation, an indoor performance evaluation method uses a solar radiation simulator in indoor chambers, and an outdoor performance evaluation method uses natural solar radiation in outdoors. The thermal performance evaluation has to ensure the reliability of the thermal performance of the collector using the outdoor performance evaluation method that is affected by the changes in the seasonal outside air temperature. This study compared and analyzed the thermal performance of the glazed solar air collector depending on ambient temperature variations in February, March, and April. The average outside air temperature was -0.5°C in February, 13.4°C in March, and 21.1°C in April. The experiment indicated that the solar air collector thermal performance was 68.1% in February, 68.5% in March, and 63.8% in April and the temperature difference between the inlet and outlet with 1000 W/m² condition was 29.2°C in February, 27.5°C in March, and 29.0°C in April. These results indicated that seasonal ambient temperature variations had a small effect on the solar air collector thermal performance evaluation. Therefore, the result of the outdoor solar air collector thermal performance evaluation was reliable irrespective of the seasonal ambient temperature changes.

평판형 태양열 집열기와 U-tube형 태양열 집열기를 적용한 나노유체 농도에 따른 성능 특성 비교

김진현(Jinhyun Kim),김형민(Hyungmin Kim),조홍현(Hong Hyun Cho) 대한설비공학회 2016 대한설비공학회 학술발표대회논문집 Vol.2016 No.6

There are some methods about increasing the thermal efficiency of the solar collector by the structure of collector, solar collector system, solar reflectance, the glass surface of the surface treatment methods and so on. In this study, Al₂O₃-nanofluid with various concentrations was investigated by using the flat-plate and U-tube solar collector. As a result, the efficiency of flat-plate solar collector was batter than U-tube solar collector and it was increased by 5%~8%. Besides, the optimal concentration of nanofluid was 1.0vol% and the efficiency of flat-plate solar collector was reached up to 70% when the Al₂O₃-nanofluid was applied as the working fluid.