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Research Article
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Research on VVVF Variable Flow Control Geothermal Heating and Cooling System that Can Improve System COP and Reduce Noise
시스템 COP 향상과 소음 저감이 가능한 VVVF 변유량 제어 지열냉난방시스템 연구
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Euikwon Jeong, Taejun Park, Juntae Jeon, Sunwoo Lim, Beomjun Kim, Seung-Ho Song, Juyeop Choi
정의권, 박태준, 전준태, 임선우, 김범준, 송승호, 최주엽
- Most geothermal cooling and heating systems operate with a refined degree of precision. The direct start method, a straightforward approach, repetitively starts …
- Most geothermal cooling and heating systems operate with a refined degree of precision. The direct start method, a straightforward approach, repetitively starts and stops based on signals. This frequent cycling generates impact torque, affecting the motor gear and insulator due to voltage and current spikes, thereby reducing lifespan. The product developed in this study minimizes system load and noise by regulating the circulating pump output using the VVVF (Variable Voltage Variable Frequency) control method, which adjusts voltage and frequency to lower power consumption. Additionally, the output of the geothermal water circulation pump is adjusted based on the operating current of the geothermal heat pump according to demand. Although maximum load conditions are rare, oil-based circulation pumps are typically designed with a sufficient margin, often providing a flow rate greater than required. This feature helps reduce energy consumption. By applying these technologies, the COP (Coefficient of Performance) of the system can be improved, allowing cooling and heating systems to operate more efficiently and cost-effectively with variable flow control. - COLLAPSE
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Research on VVVF Variable Flow Control Geothermal Heating and Cooling System that Can Improve System COP and Reduce Noise
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Research Article
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The Field Demonstration Study of Curved Roof-top PV System Utilizing the Light PV Module
곡면 지붕면을 활용한 박막 태양광발전 실증연구
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Jung-Jae Park, Kihwan Kim, Yongwoo Choi, Jae Ho Yun
박정재, 김기환, 최용우, 윤재호
- The solar power generation market has experienced rapid growth in recent years, with the industry increasingly shifting towards building-integrated solar solutions due …
- The solar power generation market has experienced rapid growth in recent years, with the industry increasingly shifting towards building-integrated solar solutions due to limitations in ground-based installation sites. Building-integrated photovoltaics (BIPVs) have gained attention for their potential to efficiently utilize land resources and enhance the spatial utilization of buildings. While current BIPV systems primarily focus on utilizing roof surfaces for solar energy generation, exploring building façades (vertical surfaces) for solar power generation is essential for future advancements. To address this challenge, a novel approach is required to reduce the weight of conventional silicon solar modules. This study aimed to design, manufacture, and demonstrate thin-film solar modules that are lightweight and flexible for attachment to building exteriors. The manufactured thin-film solar modules had a conversion efficiency of 13.8% and achieved technical completeness by obtaining KS certification (KS C 8562) for thin-film solar modules. A demonstration study of a curved roof solar module was conducted to verify the performance and applicability of curved thin-film solar modules. The demonstration system had a capacity of 7.36 kWp, and its output was analyzed over 27 months. During this period, the monthly average capacity factor was 15%, demonstrating superior results compared with the utilization rate in the same region. - COLLAPSE
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The Field Demonstration Study of Curved Roof-top PV System Utilizing the Light PV Module
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Research Article
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Analysis of Stack-driven Pressure Changes Caused by Opening and Closing of Main Entrance Doors in a High-rise Residential Building Using an In-situ Virtual Sensing Method
현장 가상센싱 기술을 활용한 고층주거건물 주요 출입부 개폐에 따른 연돌효과 압력분포 분석
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Jihwan Song, Jiwon Kim, Jeonghoon Jo, Kinam Kang, Sungmin Yoon
송지환, 김지원, 조정훈, 강기남, 윤성민
- During winter, the stack effect increases pressure differences on the upper floors of high-rise buildings. When the main entrances are opened, the …
- During winter, the stack effect increases pressure differences on the upper floors of high-rise buildings. When the main entrances are opened, the neutral pressure level of the building decreases, leading to a significant increase in pressure differences on the upper floors. Thus, opening and closing the main entrances of high-rise residential buildings can cause problems. In this study, the stack-driven pressure changes caused by the opening and closing of the main entrances were analyzed using an in-situ virtual sensing method. Changes in the pressure distribution were measured starting from a condition where all main entrance doors were closed and then gradually opening each door at the lobby and underground floors. The number of floors with pressure differences exceeding 50 Pa was recorded for each case. During peak commuting times, when all main entrance doors were opened, compared to when all entrances were closed, the pressure difference at the dwelling unit doors on the top floor increased by 11 Pa, and the number of floors at risk increased by 8. Under the coldest conditions, it increased by 24 Pa, and the number of floors at risk increased by 9. This study highlights the importance of managing main entrance doors and employing in-situ virtual sensing methods to reduce stack-driven pressure differences during building operation. - COLLAPSE
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Analysis of Stack-driven Pressure Changes Caused by Opening and Closing of Main Entrance Doors in a High-rise Residential Building Using an In-situ Virtual Sensing Method
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Research Article
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Analysis of Building Energy Performance with Application of Semi-Transparent BIPV Window Systems
반투과형 BIPV 창호시스템 적용에 따른 건물 에너지 성능 분석
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Hayeong Kim, Jinhee Kim, Juntae Kim
김하영, 김진희, 김준태
- Residential and commercial buildings often feature high window-to-wall ratios, leading to increased use of window-type BIPV systems for visibility and energy production. …
- Residential and commercial buildings often feature high window-to-wall ratios, leading to increased use of window-type BIPV systems for visibility and energy production. Unlike standard windows, window-type BIPV systems incorporate semi-transparent thin-film PV modules on the front, altering optical properties such as the Solar Heat Gain Coefficient (SHGC) and Visible Light Transmittance (VLT), as well as thermal insulation properties like overall thermal transmittance. Because the optical and thermal characteristics of windows affect building energy performance, it is crucial to analyze these characteristics in window-type BIPV systems and study their impact on energy performance. This study compares and analyzes the optical and thermal insulation characteristics of a window-type BIPV system with transmissive thin-film CIGS solar cells through simulations. These results are compared with those of general window systems to identify changes in energy performance when applied to residential buildings. The analysis shows that the thermal transmittance increased by 1.25% when PV modules were added to the general window system, while the SHGC decreased by 59.4% and the VLT decreased by 75.8%. Additionally, in buildings, annual heat gain through windows decreased by approximately 38%, resulting in a cooling load reduction of approximately 1.7% and a heating load increase of approximately 2%. Overall, the total energy load of the buildings increased. However, the total energy production of the building was approximately 27 kWh more than the total energy load due to energy production from PV power generation. - COLLAPSE
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Analysis of Building Energy Performance with Application of Semi-Transparent BIPV Window Systems
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Research Article
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Analysis of Influencing Factor on Supply Fan Temperature Rise of Air Handling Unit in Variable Air Volume System
변풍량 시스템에서 공조기 급기팬의 발열 인자 분석
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Woo-sung Jung, Jin-hyun Lee, Hyo-jun Kim, Hye-in Lee, Young-hum Cho
정우성, 이진현, 김효준, 이혜인, 조영흠
- An economizer system reduces the energy consumed by an air-handling unit while maintaining indoor comfort. The economizer system reduces the cooling load …
- An economizer system reduces the energy consumed by an air-handling unit while maintaining indoor comfort. The economizer system reduces the cooling load and energy consumption by adjusting the amount of outside air introduced when the outside temperature is lower than the indoor temperature. The fan operation in the air-handling unit causes pressure losses, such as heat, vibration, and noise. The heat generated from the air supply fan causes a temperature difference between the front and rear ends of the fan, and the actual supplied air temperature differs from the set temperature of the system. In this study, the factors affecting the temperature rise of the air supply fan were analyzed experimentally, and the terminal damper opening rate and fan speed were selected as variables to check the heat generation of the air supply fan owing to the changes in the air flow rate and differential pressure in the variable air flow system. The experiment confirmed the temperature difference according to the changes in the air flow rate and differential pressure. Additionally, using multiple regression analysis, a model was developed for predicting the increase in the air supply fan temperature. The terminal damper opening rate and fan speed were set as the independent variables, and the temperature difference was set as the dependent variable. A comparison of the predicted and experimental values using the developed prediction model revealed that R2 was 0.95. - COLLAPSE
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Analysis of Influencing Factor on Supply Fan Temperature Rise of Air Handling Unit in Variable Air Volume System
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Research Article
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Estimating the ELCC-based Marginal Capacity Credits of Renewable Energy in Korea
국내 재생에너지의 ELCC 기반 한계 용량크레딧 산정에 관한 연구
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Chunhyun Paik
백천현
- Solar and wind power are anticipated to play significant roles in Korea's future power generation mix. This study estimates Capacity Credit (CC) …
- Solar and wind power are anticipated to play significant roles in Korea's future power generation mix. This study estimates Capacity Credit (CC) using the effective load-carrying capability (ELCC) method, which is essential for evaluating the contribution of renewable energy to peak electricity demand and for long-term economic capacity planning. By introducing the concept of marginal CC, we analyzed various scenarios using five years of data on electricity demand and capacity factors for solar and wind power. The results highlight the impact of baseline capacity on the marginal CC for different renewable energy target capacities, emphasizing the potential for optimal capacity combinations. This study offers insights for policymakers aiming to integrate renewable energy effectively while maintaining the reliability of power systems. - COLLAPSE
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Estimating the ELCC-based Marginal Capacity Credits of Renewable Energy in Korea
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Review
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Recent Studies on Degradation Mechanism of Organic-inorganic Hybrid Perovskite Materials for Photovoltaics
유무기 복합 페로브스카이트 태양전지 물질의 열화 메커니즘 최신 연구 동향
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Donghyeon Lee, Sua Park, Shinhyun Kim, Min-cheol Kim
이동현, 박수아, 김신현, 김민철
- Hybrid organic-inorganic perovskite solar cells (PSCs) are promising candidates for next-generation photovoltaics due to their excellent performance, flexibility, and low-cost production. Despite …
- Hybrid organic-inorganic perovskite solar cells (PSCs) are promising candidates for next-generation photovoltaics due to their excellent performance, flexibility, and low-cost production. Despite these advancements, significant challenges remain, particularly concerning long-term stability and scalability, which are critical for commercialization. The primary stability issues stem from the degradation of perovskite materials, resulting in reduced light absorption and increased defects. Although progress has been made in developing more stable materials and effective encapsulation techniques, achieving long-term durability for PSCs remains challenging. This review identifies five major factors causing perovskite degradation and explores the underlying mechanisms: exposure to light, oxygen, moisture, ion migration, thermal instability, and mechanical deformation. Addressing these issues is crucial to improving the stability and commercial viability of PSCs and other perovskite-based optoelectronic devices. - COLLAPSE
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Recent Studies on Degradation Mechanism of Organic-inorganic Hybrid Perovskite Materials for Photovoltaics
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Research Article
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Correlation Analysis Study between BIPV Energy Generation of Zero Energy Building and Weather Data
제로에너지건축물의 BIPV 에너지 생산량과 기상 데이터의 상관 관계 분석 연구
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Hyo-Moon Cho, Soon-Myung Lee
조효문, 이순명
- This study investigated whether building integrated photo voltaic (BIPV) can achieve energy independence in zero-energy buildings. We analyzed BIPV energy generation data …
- This study investigated whether building integrated photo voltaic (BIPV) can achieve energy independence in zero-energy buildings. We analyzed BIPV energy generation data from a certified zero-energy building to verify this. The first method involved analyzing the correlation between the energy generation data and BIPV installation factors. The energy generation by BIPV based on installation factors, such as location and direction, were analyzed at minute intervals for one year. Additionally, the energy generation performance was compared using the Capacity Utility Factor, which is a measure of the power generation facility utilization rate. The second method was a correlation analysis between the energy generation data and environmental factors. The environmental factors included time and 21 types of numerical meteorological data. Among these factors, solar radiation had the strongest correlation with energy generation. Bases on this finding, verification was performed by comparing solar radiation data with energy generation data. This verification confirmed the presence of a transmission error in the BIPV inverter data. - COLLAPSE
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Correlation Analysis Study between BIPV Energy Generation of Zero Energy Building and Weather Data
Journal Informaiton
Journal of the Korean Solar Energy Society
Journal of the Korean Solar Energy Society
Korean Solar Energy Society
한국태양에너지학회
SJ Tower 804, 249, Hannuri-daero, Sejong-si, 30127, Korea
Tel: +82-44-864-1977 / Fax: +82-44-864-1978 / E-mail: solar@kses.re.kr Copyright© Korean Solar Energy Society. Powered by APUB
Tel: +82-44-864-1977 / Fax: +82-44-864-1978 / E-mail: solar@kses.re.kr Copyright© Korean Solar Energy Society. Powered by APUB