Comparison of volume flow rate and volume-averaged local mean age of air for evaluating ventilation performance in natural ventilation

박진수,이광훈 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.12

Evaluating the ventilation performance is an important part of natural ventilation studies. We considered the volume flow rate, which is used by many researchers, and the volume-averaged Local mean age of air (LMA) as the ventilation performance parameters to evaluate the performance of natural ventilation. Computational fluid dynamics (CFD) simulations were performed on an isolated building model of cross ventilation that contained two openings on the windward and leeward wall and single-sided ventilation model that consisted of a single opening. Parametric studies were performed to evaluate the ventilation performance of eight different building configurations in cross ventilation and single-sided ventilation. Using the volume flow rate it was difficult to evaluate the ventilation performance when the inlet and outlet were very close in cross ventilation and, in single-sided ventilation, it was difficult to evaluate when the airflow speed was fast near the opening but did not penetrate inside the building. While the volume-averaged LMA was an adequate parameter for representing the ventilation performance of the building, the LMA field was a more accurate representation of the local ventilation performance inside the building than the velocity vector field.

전통한지를 이용한 자연 화기구 개발에 관한 연구

김태중(Kim Tae-Jung),박준석(Park Jun-Seok) 한국건축친환경설비학회 2008 한국건축친환경설비학회 학술발표대회 논문집 Vol.- No.-

The purpose of this study is to develop natural ventilation openings which improve natural ventilation performance of an apartment using ventilation performance and thermal insulation performance of Hanji. The first experiment is to make four different kinds of single layer of Hanji and evaluate ventilation performance by KSF 2292. The second experiment is selecting two kinds of Hanji which have better ventilation performance according to the evaluation of the first experiment and evaluating ventilation performance. The third experiment is to make the model consisted of the third layers of Hanji and to be simplified into one dimension and heat exchange performance was evaluated in the chamber with high and low temperature by pressure differences. As a result of the first experiment, ventilation rate from Hanji of 0.03㎜ is 6~7 times higher than the Hanji of 0.1㎜, and the pressure loss is the lowest from that of 0.05㎜. Heat exchange performance from the third layers was observed as 17~25% in terms of heat exchange efficiency and 47w/㎡~70w/㎡ in heat exchange rate. Therefore, natural ventilation openings which are able to exchange heat are adapted to hybrid ventilation system with mechanical ventilation system and are considered to save energy as well as preventing cold draft.

제트팬 적용에 따른 대규모 지하주차장의 환기성능 예측 평가

이민정(Lee Min Jung),여인애(Yeo In-Ae),정용호(Jung Yong-Ho),윤성환(Yoon Seong-hwan) 한국건축친환경설비학회 2008 한국건축친환경설비학회 학술발표대회 논문집 Vol.- No.-

Large underground car parks require high performance of their ventilation systems, due to toxic chemicals or substances which could possibly harm humans. Jet fan ventilation systems have been employed frequently in these large underground car parks recently, as it assists, to achieve the optimal air quality of them effectively. The performance of this ventilation system, however, can be altered by the numbers of jet fans in uses and the arrangements. The aim of this study, therefore, is to estimate the performance of Jet fan ventilation systems, according to these factors. To look at 3 cases each with, differing numbers of jet fans and how the intervals between them affects overall performance. Fluent 6.0, one of the most commonly used CFD codes, is employed for the numerical analysis of this study and the results are evaluated both by case to case analysis and at each designated height level of the space.

실별 환기시스템 적용에 따른 공동주택 에너지 소비량 및 환기성능 예측

조현(Hyun Cho),최인창(In-Chang Choi),방승기(Seung-Ki Pang) 한국생활환경학회 2011 한국생활환경학회지 Vol.18 No.4

In this study, Individual room control ventilation system be applied to plate type and tower type apartment housing in accordance with the ventilation system operating conditions were studied in energy consumption and indoor ventilation performance. Master ventilation system is composed of unit that has airflow of 250CMH and diffuser with electrical control damper in order to control indoor air for each room. Moreover, electricity consumption and sound-level of ventilation unit in each room are measured with hourly base, and indoor airflow pattern and energy consumption are analyzed by simulation program based on applying same condition to the building that is currently under construction. Consequently, the result of this research shows that room control ventilation system is desirable method in terms of energy saving because it control and operates ventilation system as much as each room needs, and profound research need to be proceeded on it.

노후 공동주택 리모델링 단위평면 채광 및 환기 성능 분석

최재필,최준호,백수연,염수,김정우 대한건축학회 2020 대한건축학회논문집 Vol.36 No.11

The purpose of this study is to quantitatively analyze the lighting and ventilation performance of a 2-bay type of remodeling unit plan, andto propose lessons for improving environmental performance. For the data for analysis, three remodeling unit plans were applied. Themethodology of the study adopted a method that allows lighting and ventilation to be quantitative. For the lighting analysis, a methodologyto derive the LEED standard sDA index was applied, and the ventilation analysis was to analyze the natural ventilation performance in thecomplex and unit plan through the CFD analysis program as an AOA index. The results of the study are as follows. The lightingperformance is expected to show similar lighting performance to the existing floor plan through the remodeling planning. In terms ofventilation, performance is expected to decrease in some areas, but performance is expected to improve through window planning adjustment. 본 연구는 1기 신도시에 가장 많이 공급된 2베이 대표유형의 리모델링 전후 평면에 대한 채광 및 환기 성능을 정량적으로 분석하고, 환경 성능 개선을 위한 교훈 등을 제안하는 것을 목적으로 한다. 분석을 위한 자료로는 선행 연구에서 도출한 리모델링 전후 계획안을 적용하되, 환경 성능을 향상시킬 수 있는 계획 대안을 추가로 제안하여 함께 분석을 수행하고자 하였다. 연구의 방법론은 채광 및 환기를 정량적으로 검증할 수 있는 방법론을 채택하였다. 채광분석은 LEED기준의 sDA지표를 도출할 수 있는 Diva를 적용하였고, 환기 분석은 CFD분석 프로그램을 통해 단지와 주호에서의 자연환기 성능을 공기연령(Age of Air)지표로 분석하고자 하였다. 연구의 결과는 다음과 같다. 채광 성능에 대해서는 리모델링 평면 계획에 따라 ‘리모델링 전’ 평면에 유사한 채광 성능을 확보할 수 있을 것으로 기대된다. 환기의 측면에서는 ‘리모델링 전’ 평면에 비하여 환기 성능이 일부 범위에서 떨어지는 것으로 나타났지만, 내부 평면계획 및 환기창 계획 등을 통해 개선할 수 있을 것으로 기대한다.

A study on the evaluation of ventilation system suitable for outside air cooling applied in large data center for energy conservation

Yong-Il Kwon 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.5

In developed countries, expansion of communication technology has resulted in continual increase in the construction of data centers with high-density cooling loads. Throughout a year, IT equipment installed in a data center generates large and constant cooling load. As a result, data centers may be consuming an ever-growing amount of energy. The cooling system utilizing the energy of outside air is applied universally to reduce data center energy consumption. The application of the cooling system to the outdoor air cooling system of a data center considers that temperature efficiency and ventilation performance vary depending on the type of ventilation system. The displacement and mixed ventilation method can be applied generally to a data center. The efficiency of a ventilation system depends on inside temperature or contaminant concentrations in room and outlets. This study thus aims to evaluate the ventilation performance that varies according to type of ventilation system installed in the data center. Ventilation efficiency is assessed by applying the concept of total air age and considers the fresh air ratio and age of return air. Further, temperature efficiency gained by utilizing temperature difference is used to assess causes for changes in ventilation performance.

고층공동주택 커튼월의 창호개폐방식 변경에 따른 환기량 평가

조현(Cho Hyun),방승기(Pang Seung-Ki) 대한건축학회 2011 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.31 No.2(계획계)

In this study of high-rise apartment windows open system based on indoor air may aim to predict the ventilation performance. To this end, Project-out windows the way the ventilation performance was measured, using CFD simulations, the windows installation Casement-in air ventilation performance boost by predicting the performance was evaluated. As a results, located on the front of the households had appeared to be a high number of ventilation performance, Casement-in windows installation is six to 12 times the number of air that was predicted to increase ventilation performance. Indoor air for improved ventilation performance in high-rise apartment windows Casement-in appeared to be favorable.

다기능온돌시스템을 이용한 자연환기성능 평가

조동우(Cho Dong-Woo),유기형(Yu Ki-Hyung),유정연(Yu Jung-Yeon) 대한건축학회 2007 대한건축학회논문집 Vol.23 No.11

In Korea, all residential buildings adopt floor-heating systems for indoor thermal comfort. And the ratio of multi-family houses exceeds 50%. Lately problems of noise between floors and contamination of indoor air in multi-family houses emerged as social issue, and performance standards related to noise between floors and ventilation were established in Housing Regulation. Concerning these issues, many systems have been developed. Recently developed raised floor heating system is not only capable of basic function to reduce noise between floors, but also is a multi-functional floor heating system enabling natural ventilation. The procedure of this system for natural ventilation is to import outdoor air through bottom space of the floor heating system, circulate indoor space and discharge it out of ceiling. In winter, powerless natural ventilation is possible with buoyancy effect caused by temperature difference between outdoor and indoor. And it also allows saving of energy by importing pre-heated air in bottom space of the floor heating system. To evaluate ventilation performance of this system, on-site measurement was conducted in 2 test laboratories, and the nominal air change rate was satisfied as 0.4~0.8 h<SUP>-1</SUP> under the condition of outdoor temperature 5℃~-5℃, which was evaluated as highly possible to be applied as a natural ventilation system in multi-family houses. So, this system as hybrid ventilation system using natural ventilation is evaluated as highly possible for application. It also allows saving of energy by importing pre-heated air in bottom space of the floor heating system. Moreover, it was proven that air temperature at supply grille was maintained higher than indoor temperature, by which it was proven to enable blocking of cold draft problem.

환기시스템 온도조건에 따른 히트펌프 난방성능 실험연구

이권재(K. J. Lee),김정석(J. S. Kim),백대성(D. S. Back),이상재(S. J. Lee),한화택(H. T. Han),이인복(I. B. Lee),한건수(G. S. Han) 대한설비공학회 2010 대한설비공학회 학술발표대회논문집 Vol.2010 No.11

전산실의 환기성능 최적화를 위한 연구

권용일(Yong-il Kwon) 대한설비공학회 2015 설비공학 논문집 Vol.27 No.2

The objective of the present study is to identify the ventilation problems and to suggest the optimal ventilation system to save energy and to improve IAQ in the computer rooms, which annually performs the cooling operation by the server with the highly thermal load. Numerical results on the temperature and local mean age are presented along with some of the discharge velocities. Results show many interesting aspects of airflow patterns affecting the ventilation performances, according to the discharge velocity of the supply diffuser installed in the bottom surfaces between the servers. As the results, 2.5 m/s of the optimal discharge velocity is needed in order to improve the ventilation performance.