An integrated evaluation of productivity, cost and CO₂ emission between prefabricated and conventional columns

Jeong, Jaewook,Hong, Taehoon,Ji, Changyoon,Kim, Jimin,Lee, Minhyun,Jeong, Kwangbok,Lee, Seunghwan Elsevier 2017 Journal of cleaner production Vol.142 No.4

<P><B>Abstract</B></P> <P>The off-site prefabrication construction method offers several advantages that have positioned it as a good alternative to the conventional method. Recently in South Korea, a form-latticed prefabricated steel reinforced concrete (Form-LPSRC) column was invented as substitute for a conventional steel reinforced concrete (SRC) column. This study evaluates the productivity, cost, and CO<SUB>2</SUB> emission of Form-LPSRC column with those of SRC column through a case study. Two factory projects utilizing same-size Form-LPSRC and SRC columns are studied. In addition, Web-CYCLONE simulation and equation-based methods are utilized to calculate the productivity, cost, and CO<SUB>2</SUB> emission of the two column methods. In particular, Web-CYCLONE simulation is used for considering the idle time during the construction process. The Form-LPSRC column improved productivity by 42.5% and provided costs savings of 1.32% compared with the SRC column. Thus, the Form-LPSRC column is excellent for projects where construction duration and cost are of utmost importance. However, the CO<SUB>2</SUB> emission of the Form-LPSRC column is 72.18% higher than that of the SRC column.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Form-LPSRC column was invented as substitute for a conventional SRC column. </LI> <LI> This study evaluated two methods in terms of productivity, cost, and CO<SUB>2</SUB> emission. </LI> <LI> Web-CYCLONE simulation and equation-based methods were utilized for case study. </LI> <LI> Form-LPSRC column improved productivity by 42.5% and saved costs of 1.32%. </LI> <LI> CO<SUB>2</SUB> emission of Form-LPSRC column is 72.18% higher than that of SRC column. </LI> </UL> </P>

Development of an evaluation process for green and non-green buildings focused on energy performance of G-SEED and LEED

Jeong, Jaewook,Hong, Taehoon,Ji, Changyoon,Kim, Jimin,Lee, Minhyun,Jeong, Kwangbok Elsevier 2016 Building and environment Vol.105 No.-

<P><B>Abstract</B></P> <P>This study aims to develop an evaluation process for comparing the energy performances of Green and non-Green buildings. The information on the building attributes and energy consumption of 455 multi-family housing complexes (MFHCs) in 2014, including 321 non-certified MFHCs and 126 MFHCs that accredited Green Standard for Energy and Environmental Design (G-SEED) certification (an official Green Building certification in South Korea) and 8 MFHCs that accredited Leadership in Energy and Environmental Development (LEED) certification, were applied to the empirical study. Data-mining techniques are applied to develop the comparison groups considering various building attributes, and the database was classified into four groups based on the average enclosed area per household (AEA). It was shown that the large-AEA groups (i.e., Group 4, over 143.47 m<SUP>2</SUP>) had less energy use intensity (EUI) than the small-AEA groups (i.e., Group 1, under 97.04 m<SUP>2</SUP>). The mean of site EUI for Groups 1, 2, 3, and 4 were significantly different (125.29, 116.35, 110.89, and 101.00 kWh/m<SUP>2</SUP>∙y, respectively). While the G-SEED- and LEED-certified MFHCs were considered to have up to 10 and 15% energy savings, respectively, compared to all non-certified MFHCs, the comparative analysis by the developed Groups 1, 2, 3, and 4 revealed that the G-SEED-certified MFHCs and the non-certified MFHCs had no significant differences in energy performance. Therefore, the energy performance rating system of G-SEED should be revised. The proposed energy performance evaluation process can also be useful in identifying the energy performance of other buildings.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Energy performance of green building certifications needs to be evaluated. </LI> <LI> Energy performance evaluation process for buildings was developed. </LI> <LI> 126 G-SEED, 8 LEED, and 321 non-certified MFHCs were evaluated using the process. </LI> <LI> G-SEED and LEED have no significant energy savings compared to non-certified MFHCs. </LI> <LI> LEED has bigger potential for reducing energy consumption than G-SEED. </LI> </UL> </P>

Development of a prediction model for the cost saving potentials in implementing the building energy efficiency rating certification

Jeong, Jaewook,Hong, Taehoon,Ji, Changyoon,Kim, Jimin,Lee, Minhyun,Jeong, Kwangbok,Koo, Choongwan Elsevier 2017 APPLIED ENERGY Vol.189 No.-

<P>Building energy efficiency rating (BEER) certification is an energy performance certificates (EPCs) in South Korea. It is critical to examine the cost saving potentials of the BEER-certification in advance. This study aimed to develop a prediction model for the cost saving potentials in implementing the BEER certification, in which the cost saving potentials included the energy cost savings of the BEER certification and the relevant CO2 emissions reduction as well as the additional construction cost for the BEER-certification. The prediction model was developed by using data mining, life cycle cost analysis, real option valuation, and Monte Carlo simulation. The database were established with 437 multi-family housing complexes (MFHCs), including 116 BEER-certified MFHCs and 321 non-certified MFHCs. The case study was conducted to validate the developed prediction model using 321 non-certified MFHCs, which considered 20-year life cycle. As a result, compared to the additional construction cost, the average cost saving potentials of the 1st-BEER-certified MFHCs in Groups 1, 2, and 3 were predicted to be 3.77%, 2.78%, and 2.87%, respectively. The cost saving potentials can be used as a guideline for the additional construction cost of the BEER-certification in the early design phase. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Development of an integrated energy benchmark for a multi-family housing complex using district heating

Jeong, Jaewook,Hong, Taehoon,Ji, Changyoon,Kim, Jimin,Lee, Minhyun,Jeong, Kwangbok Elsevier 2016 APPLIED ENERGY Vol.179 No.-

<P>The reliable benchmarks are required to evaluate building energy efficiency fairly. This study aims to develop the energy benchmarks and relevant process for a multi-family housing complex (MFHC), which is responsible for huge CO2 emissions in South Korea. A database, including the information on building attributes and energy consumption of 503 MFHCs, was established. The database was classified into three groups based on average enclosed area per household (AEA) through data mining techniques. The benchmarks of site energy use intensity (EUI), source EUI, and CO2 emission intensity (CEI) were developed from Groups 1, 2, and 3. Representatively, the developed benchmarks of CEI for Groups 1, 2, and 3 were 28.17, 24.16, and 20.96 kg-CO2/m(2) y, respectively. A comparative analysis using the operational rating identified that the developed benchmarks could solve the irrationality of the original benchmarks from overall database. In the case of the original benchmarks, 93% of small-AEA-groups and 16% of large AEA-groups received lower grades. In the case of the developed benchmark, the upper and lower grades in Groups 1-3 were both adjusted to 50%. The proposed process for developing energy benchmark is applicable to evaluate the energy efficiency of other buildings, in other regions. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Improvements of the operational rating system for existing residential buildings

Jeong, Jaewook,Hong, Taehoon,Ji, Changyoon,Kim, Jimin,Lee, Minhyun,Jeong, Kwangbok,Koo, Choongwan Elsevier 2017 APPLIED ENERGY Vol.193 No.-

<P>The Building Energy Consumption Certification (BECC) evaluating the energy performance of existing buildings has been launched since 2016 to reduce the operational energy consumption in existing buildings in South Korea. However, the current BECC has some potential problems, and these problems should be solved to evaluate the energy performance of existing building more accurately. Thus, this study aims to identify the potential problems in the current BEEC using the hypothesis testing. And then this study proposes the improved BECC using the energy benchmarking process and the modified grading process to solve the potential problems. As a result of the hypothesis testing based on the data of 504 multi-family housing complexes (MFHCs), the potential problems were identified as follows: (i) the current classification criteria caused the irrational judgements, and (ii) the current grading system was lacking in its assessment function (over 94% of MFHCs ranked in the average level as grades 'C' and 'D'). To solve these problems, this study proposed the improved BECC. The energy benchmarking process provides the reasonable classification criteria, and the modified grading process finds the reasonable number of grades and its range. The result of comparative analysis based on 504 MFHCs indicated that the improved BECC could solve the problems in the current BECC. That is, over 94% of MFHCs were ranked in grades 'C' and 'D' in the current BECC while they were shown in all five grades (i.e., grades 'A', 'B', 'C', 'D', and 'E') in the improved BECC. The policy-makers can more accurately assess the energy performance of existing MFHCs by using the improved BECC. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Effect of Biochar Amendment on Greenhouse Emissions from Rice Paddy and Sugarcane Soils in the Subtropical Region of USA

Changyoon Jeong,Jim Wang,Dustin Harrell 한국토양비료학회 2014 한국토양비료학회 학술발표회 초록집 Vol.2014 No.6

Carbon Nanocomposite Based Mechanical Sensing and Energy Harvesting

Changyoon Jeong,Chanwoo Joung,Seonghwan Lee,Maria Q. Feng,Young-Bin Park 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.7 No.1

Progresses in sensor and energy technologies have been an important driving force for the rapid development of these industries and have drawn the attention of researchers on environmental concerns. In particular, carbon nanomaterial (carbon nanotubes, graphene, graphite, etc.)-based composites are widely used for sensor and energy harvesting applications owing to their excellent electrical, thermal, and mechanical properties. In this review, we have discussed various aspects of the use of carbon nanocomposites for the development of sensor and energy harvesting devices. These devices have shown outstanding sensing and energy harvesting performances. Various carbon nanomaterial-based composites with sophisticated structural and material designs have been developed to improve their sensing performance for various applications. We have also reviewed recent technological developments in carbon nanocomposite-based energy generators that adopt thermoelectric and triboelectric working mechanisms. Further research on the development of carbon nanocomposites with enhanced sensing and energy harvesting properties will expand the range of their applications to automotive, aerospace, artificial skin, healthcare, and environmental/infrastructure industries.

Enhancing mechanical properties of carbon fiber reinforced plastics by synergistic interaction of ZnO and CNTs

Hongjun Jeong(정홍준),Shushuai Zhu,Changyoon Jeong(정창윤) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.6

크루즈 관광 기억의 선명도를 극화시키는 체험경제요소 고찰과 충성도에 미치는 효과 분석

정창윤(Jeong, Changyoon),김인신(Kim, Insin),김이태(Kim, Yi-Tae) 한국관광레저학회 2016 관광레저연구 Vol.28 No.1

외식업 종사자의 심리적 주인의식을 향상시키는 긍정심리자본 및 직무자원 요인 고찰

정창윤(Jeong, Changyoon),김인신(Kim, Insin) 한국관광레저학회 2015 관광레저연구 Vol.27 No.4