• Research Article

    Silicon Recovery from Solar Module Waste by a Physical Method

    물리적 방법에 의한 태양광 폐모듈로부터 실리콘 회수

    Yoon Dae-Sik ・ Ahn Young-Soo ・ Kang Gi-Hawn ・ Chang Hyo Sik ・ Lee Jin-Seok

    윤대식, 안영수, 강기환, 장효식, 이진석

    This paper describes the physical process used to recover silicon from a solar module, where the solar cell recovery rate (87.4 %) … + READ MORE
    This paper describes the physical process used to recover silicon from a solar module, where the solar cell recovery rate (87.4 %) was determined under optimized process conditions. This physical recycling method requires a particle separation process because selective separation of the recovered materials is difficult, and the recovery rate and purity of the recovered materials can be low after the initial particle separation. In this study, the recovery rate was determined with respect to the crushing time and rotational speed of the cutter mill as well as the amplitude and separation time of the sieving machine, which were optimized to increase the Si recovery rate. In addition, an etching process was used to recover high-purity Si from the solar cells. To determine whether Ag and Al were removed from the recovered Si, XRD analysis was performed to confirm the measured Si peak and small TiO2 peak, and ICP-MS analysis was performed to confirm the purity of the recovered Si, which was found to be of 3N grade. - COLLAPSE
    30 June 2022
  • Review

    Trend Summary by SCOPUS Literature Analysis on Machine Learning Assisted BIPV Research

    SCOPUS 문헌 정보 분석을 통한 머신 러닝 활용 BIPV 연구 동향

    Lee Jehyun ・ You Sihyun ・ Kim Chang Ki ・ Oh Myeongchan ・ Kim Boyoung ・ Kang Yong-Heack ・ Kim Hyun-Goo

    이제현, 유시현, 김창기, 오명찬, 김보영, 강용혁, 김현구

    With the accelerated development of science and technology across fields, publications in almost all fields have increased exponentially every year. According to … + READ MORE
    With the accelerated development of science and technology across fields, publications in almost all fields have increased exponentially every year. According to the Scopus search, the number of papers related to buildings and solar energy that used machine learning has grown at an average annual rate of 16.1%, exceeding 3000 publications since 2019. Review papers have been published consistently since 2010, demonstrating that they are on a trajectory of initial growth. Because there is a limit to reading and analyzing large quantities of papers every year, we developed a methodology that reads, analyzes, and visualizes published literature information. In this method, we provide a query to the Scopus database to retrieve data and then visualize the number of publications by year, journal, and keyword along with other analyses results. The relationship and frequency analyses results can also be shown among words in titles, keywords, and abstracts. Analysis of research on building-integrated photovoltaics yielded the result that publishing on Energy and Buildings (impact factor [IF] 4.067, modified rank normalized impact factor [mrnIF] top 1.7%) and Solar Energy (IF 4.018, mrnIF top 1.7%) is active. Over the past 10 years, approximately 1–1.5% of machine learning-related research has been published, with a gradual increase. - COLLAPSE
    30 June 2022
  • Research Article

    Analysis of Load Matching and Grid Interaction of a Zero Energy Building

    제로에너지건물 사례를 통한 부하매칭율 및 건물과 계통간의 송·수전량 변동성 분석

    Kim Ha-Yeong ・ Jeong Su-Bin ・ Kim Jin-Hee ・ Kim Jun-Tae

    김하영, 정수빈, 김진희, 김준태

    Zero energy buildings apply energy efficiency measures and renewable energy systems to maintain a zero energy consumption balance over a specific time. … + READ MORE
    Zero energy buildings apply energy efficiency measures and renewable energy systems to maintain a zero energy consumption balance over a specific time. Renewable energy systems installed in zero energy buildings produce energy to cover their energy demand, and the surplus energy can be transmitted to the grid. Conversely, the building can receive power from the grid when the energy consumption is greater than the energy production. However, the greater fluctuation of transmitted and received power in the transfer process results in lower grid stability. Therefore, for zero energy buildings, it is necessary to evaluate the load matching rate and power transmission between the building and the grid. However, in the case of zero-energy building certification in Korea, it is impossible to evaluate the load matching rate because it only considers the building's annual energy consumption and production volume. This study investigated the energy balance of a zero energy building-certified case in terms of load matching and grid interaction evaluation indicators. Based on the results, the Load Cover Factors (LCF) analyzed at intervals of 10 minutes, 1 day, and one month were 0.421, 0.929, and 0.996, and, correspondingly, the Supply Cover Factors (SCF) were 0.228, 0.544, and 0.536 under the same analysis conditions. In addition, the variabilities of the amount of transmitted and received power were confirmed to be 0.203, 0.286, and 0.305, respectively. - COLLAPSE
    30 June 2022
  • Research Article

    Evaluation of Heat Transfer Performance Depending on Semicircular Turbulence Promoter Shape Conditions and Flow Conditions in the Air-Type PV/T Collector

    공기식 태양광/열 집열기 내 반원 난류 촉진제 형상조건과 유동 조건에 따른 열전달 성능 평가

    Kim Junyeop ・ Kim Seongbhin ・ An Byunghwa ・ Choi Hwiung ・ Choi Kwanghwan

    김준엽, 김성빈, 안병화, 최휘웅, 최광환

    Air-type photovoltaic thermal (PV/T) collectors have a lower heat recovery rate than liquid-type collectors. Therefore, in this study, semicircular turbulence promoters were … + READ MORE
    Air-type photovoltaic thermal (PV/T) collectors have a lower heat recovery rate than liquid-type collectors. Therefore, in this study, semicircular turbulence promoters were attached to the back of the PV cell to improve the heat recovery rate. Based on computational fluid dynamics, the heat-transfer performance and pressure drop were evaluated by changing the Reynolds number (Re) and semicircular turbulence promoter shape conditions. The turbulence promoter shape conditions include the relative height and relative pitch of the turbulence promoter. In addition, the increasing ratio, which means an increase in height of the turbulence promoter in the direction of flowing air, the length of the turbulence promoter, and the distance between the turbulence promoters were considered as design parameters. Consequently, the heat transfer performance increased with a decrease in relative height of turbulence promoter, while the pressure drop increased with an increase in relative height of turbulence promoter. Also, both the heat transfer performance and pressure drop show better performance as the increasing ratio of turbulence promoter decreased. The thermos-hydraulic performance parameter considering both the heat transfer performance and pressure drop presented the maximum value of 1.92 for the relative height of 0.02, increasing ratio of 1. - COLLAPSE
    30 June 2022
  • Research Article

    Projection of General Wind Turbine Technology in Future

    미래 표준 풍력터빈 기술 전망

    Kim Jin-Young ・ Kim Hyun-Goo ・ Kim Keunhoon ・ Hwang Su-Jin

    김진영, 김현구, 김건훈, 황수진

    To be feasible, a master plan for renewable energy development should be based on reliable resource assessments. In particular, to reach carbon … + READ MORE
    To be feasible, a master plan for renewable energy development should be based on reliable resource assessments. In particular, to reach carbon neutrality, long-term renewable energy potential prospects by 2050 are required. Such assessment is key to establish a future resource model by defining a proper future prospect scenario with regard to the potential determinants of future potential prospects. As part of developing future wind resource potential models, this paper describes technology scenarios deduced by statistical analysis of domestic onshore wind farm data. The rated power of the standard wind turbine was defined as 5.5, 4, and 8 MW in the moderate, conservative, and advanced scenarios, respectively. The turbine diameter, hub height, and specific power of each scenario were determined according to IEC wind classes. The results of this study are in accordance with the wind power outlooks of the USA and Europe, and are expected to be utilized as a basic reference to estimate realistic onshore wind future potentials. - COLLAPSE
    30 June 2022
  • Research Article

    Simulation Case Study of Renewable Energy Supply Obligation Ratio in the Renewable Portfolio Standard

    신재생에너지 설치의무제도의 공급의무비율에 관한 시뮬레이션 연구

    Park Seung-Hoon ・ Oh Kyong-Cheol ・ Jang Yong-Sung ・ Kim Eui-Jong

    박승훈, 오경철, 장용성, 김의종

    To achieve the goal of reducing greenhouse gas in buildings, the Korean government formulated mandatory regulations that mandate the installation of renewable … + READ MORE
    To achieve the goal of reducing greenhouse gas in buildings, the Korean government formulated mandatory regulations that mandate the installation of renewable energy systems in buildings. Because the evaluation of these regulations is conducted at the building design stage, it cannot be guaranteed that the target building will show the expected energy performance after its completion. In this study, the regulation level of renewable energy supply obligation ratio (RER) by the Korean renewable energy installation obligation was compared according to cases through hourly-basis simulations. The target renewable energy system consisted of a photovoltaic, proton-exchange membrane fuel cell, and battery energy storage system. Three different renewable energy system design scenarios were investigated to compare the annual energy production and RER calculated according to the current RER calculation methods with those obtained through simulation. The simulation results showed that the larger the capacity of the battery energy storage system, the more significant was the difference in the RER between the current calculation and simulation results. - COLLAPSE
    30 June 2022
  • Research Article

    Energy Performance Analysis of Green-Remodeling for Public Buildings under 500 m2

    소규모 그린리모델링 공공건축물의 ECO2와 DesignBuilder를 이용한 건물에너지성능 분석

    Kim Ji-Hye ・ Yu Ji-Suk ・ Kim Jin-Hee ・ Kim Jun-Tae

    김지혜, 유지숙, 김진희, 김준태

    Old buildings over 20 years after completion account for 58.2% of all buildings in Korea. Moreover, buildings built 30 years ago with … + READ MORE
    Old buildings over 20 years after completion account for 58.2% of all buildings in Korea. Moreover, buildings built 30 years ago with weak insulation levels have a significant impact on energy consumption in the building sector. Therefore, improving the performance of existing buildings is critical. In addition, green remodeling of old public buildings is currently being implemented in accordance with the mandatory zero-energy construction policy. In Korea, ECO2 based on ISO 13790 and DIN V 18599 is the program used officially to evaluate building energy efficiency ratings and energy independence rates. However, the accuracy of ECO2 is controversial because the cross-use of cooling and heating energy generated in the intermediate stage and the amount of energy used at a specific point in time cannot be analyzed. In addition, previous studies found that the results of a static analysis program showed higher energy performance than those of a dynamic analysis program. In this study, the programs ECO2 and DesignBuilder were used to analyze and compare results of the primary energy consumption (heating, cooling, hot water, lighting, and ventilation) per year for a green-remodeled small public building. Results indicated that the application of the green remodeling elements reduced the primary energy consumption per unit area the most, especially for heating energy. In addition, the change in the building energy efficiency grade through green remodeling improved by two stages from grade 1 to grade 1++ in the case of the ECO2 program, and improved by one stage from grade 1+ to grade 1++ for the DesignBuilder program. - COLLAPSE
    30 June 2022
  • Research Article

    Grey-box Model Develop and MPC Simulation of Campus Office Zone Based on Actual Measurement

    실측 데이터 기반 교육시설 건물의 Grey-box 모델 개발 및 MPC 시뮬레이션

    Choi Kwangwon ・ Joe Jaewan

    최광원, 조재완

    This study aimed to develop a grey-box building model in a zone of a high-rise building on a university campus and to … + READ MORE
    This study aimed to develop a grey-box building model in a zone of a high-rise building on a university campus and to simulate model-based predictive control. Grey-box modeling was performed using various indoor and external environment data measured within a single-person office space on a high floor. The residence schedule was indirectly calculated using values such as indoor CO2 concentration and plug power. In addition, the catalog rating value was applied as the cooling energy value of the indoor 4-ways air conditioner as this could not be measured. Measurements were performed for approximately 4-weeks, and operating data of the heat pump and non-operating (i.e., free-floating) data were obtained according to the weekday and weekend schedules. The grey-box model was parameterized using the linear time-invariant and linear time-variant models. Both models showed good predictive performance with a root mean square error of less than 1°C in the 2-week estimation and 2-week validation results. Based on these results, an MPC simulation was performed. MPC simulation in a single zone were conducted for various electricity cost structures to derive quantitative electricity cost savings compared to those of feedback control. - COLLAPSE
    30 June 2022