• Journal of Korean Society for Atmospheric Environment
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• 제23권E2호
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• pp.66-73
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• 2007

The introduction of tracer gas techniques to ventilation studies in indoor environments provides valuable information that used to be unattainable from conventional testing environments. Data acquisition systems (DASs) containing analogue-to-digital (A/D) converters are usually used to function the key role that records signals to storage in digital format. In the testing process, there exist a number of components in the measuring equipment which may produce system-based inference to the monitored results. These unwanted fluctuations may cause significant error in data analysis, especially when non-linear algorithms are involved. In this study, a pre-processor is developed and applied to separate the unwanted fluctuations (noise or interference) in raw measurements and to reduce the uncertainty in the measurement. Moving average, notch filter, FIR (Finite Impulse Response) filters, and IIR (Infinite Impulse Response) filters are designed and applied to collect the desired information from the raw measurements. Tracer gas concentrations are monitored during leakage and ventilation tests in the model test room. The signal analysis functions are introduced to carry out the digital signal processing (DSP) work. Overall the FIR filters process the $CO_2$ measurement properly for ventilation rate and mean age of air calculations. It is found that, the Kaiser filter was the most applicable digital filter for pre-processing the tracer gas measurements. Although the IIR filters help to reduce the random noise in the data, they cause considerable changes to the filtered data, which is not desirable.

• 전자공학회논문지SC
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• 제46권4호
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• pp.28-38
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• 2009

본 연구에서는 비분산적외선(NDIR) 방식의 CO$_2$센서를 이용하여 무선 센서 네트워크 기반의 지하 공기질 모니터링 시스템을 구현하고 실제 지하철 승강장에 설치한 후 성능평가를 수행하였다. 서울 지하철은 하루 650만 명이 이용하는 대표적인 대중교통 수단이다. 따라서 승객뿐만 아니라 지하철 역사의 지하 공간에서 근무하는 많은 근로자들의 건강에 대한 관심이 높아짐에 따라 지하철 역사의 공기질 모니터링에 대한 요구가 매우 높아졌다. 현재 이런 요구를 충족하기 위해 환경부와 지하철 운영기관 측에서는 지하철역 공기질 모니터링 시스템을 일부 설치 운영 중이다. 그러나 고가의 수입 센서 이용으로 장비의 규모가 크고 설치 및 상시 운영에 따른 유지보수 비용이 큰 한계점이 있다. 따라서 본 연구에서는 저비용으로 CO$_2$ 농도를 상대적으로 정밀하게 측정할 수 있는 상용화된 CO$_2$ 센서에 대해 이론적으로 분석하고 신뢰성 검증 테스트를 수행하였다. 또한 무선 공기질 측정 센서 노드 및 게이트웨이 시스템을 개발하여 지하철 승강장의 실시간 공기질 데이터를 주기적으로 수집할 수 있고, 효율적으로 모니터링 할 수 있는 웹서버를 구축하였다. 본 연구 결과는 향후 지하 공간 공기질 관리 시스템의 확산 설치를 위하여 기초 연구 자료로 활용될 것이다.

• 한국환경과학회지
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• 제17권11호
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• pp.1195-1201
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• 2008

Enhancing with non-metallic elemental nitrogen(N) is one of several methods that have been proposed to modify the electronic properties of bulk titanium dioxide($TiO_2$), in order to make $TiO_2$ effective under visible-light irradiation. Accordingly, current study evaluated the feasibility of applying visible-light-induced $TiO_2$ enhanced with N element to cleanse aromatic compounds, focusing on xylene isomers at indoor air quality(IAQ) levels. The N-enhanced $TiO_2$ was prepared by applying two popular processes, and they were coated by applying two well-known methods. For three o-, m-, and p-xylene, the two coating methods exhibited different photocatalytic oxidation(PCO) efficiencies. Similarly, the two N-doping processes showed different PCO efficiencies. For all three stream flow rates(SFRs), the degradation efficiencies were similar between o-xylene and m,p-xylene. The degradation efficiencies of all target compounds increased as the SFR decreased. The degradation efficiencies determined via a PCO system with N-enhanced visible-light induced $TiO_2$ was somewhat lower than that with ultraviolet(UV)-light induced unmodified $TiO_2$, which was reported by previous studies. Nevertheless, it is noteworthy that PCO efficiencies increased up to 94% for o-xylene and 97% for the m,p-xylene under lower SFR(0.5 L $min^{-1}$). Consequently, it is suggested that with appropriate SFR conditions, the visible-light-assisted photocatalytic systems could also become important tools for improving IAQ.

• 환경위생공학
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• 제24권4호
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• pp.60-68
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• 2009

The most principal approach to improve indoor air quality(IAQ) of subway was to examine the fine particulate(PM-10) from the emission sources. Therefore, this study was carried on the investigation the fine particulate for comparison with the removal efficiency of PM-10 in divided the PSD(Platform Screen Door) and Non-PSD subway station from July, 2007 to May 2008. In the monitoring results, the range of PM-10 concentration of Non-PSD station was $44.6{\sim}116.5{\mu}g/m^3$ and the range of PM-10 concentration of PSD station was $23.9{\sim}81.1{\mu}g/m^3$. And then the range of PM-2.5 concentration of Non-PSD station was $17.4-56.6{\mu}g/m^3$, and then the range of PM-2.5 concentration of PSD station was $17.9{\sim}34.4{\mu}g/m^3$. In comparison with the results of the PSD and Non-PSD subway station, we found that the PM-10 removal efficiency of PSD was 30-40%. In conclusion, the PSD will be applied the effective facilities of decreasing PM-10 in subway station in Korea.

• 한국안광학회지
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• 제17권2호
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• pp.215-222
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• 2012

목적: 본 연구는 콘택트렌즈 착용 여부와 사무실 실내공기질이 안구건조에 미치는 영향이 있는지 파악하고자 하였다. 방법: 71명의 연구 대상자들의 각 사무실에서 실내공기질이 안구건조에 미치는 영향을 파악하기 위하여 이산화탄소($CO_2$), 온도(temperature), 습도(relative humidity), 총 부유분진(TSP), 미세먼지($PM_{10}$), 포름알데히드(HCHO)를 측정분석 하였고, 안구 건조증을 확인하기 위하여 연구 대상자들의 사무실에서 McMonnies dry eye symptom questionnaire, Schirmer Tear Test-I(S.T.T-I), Schirmer Tear Test-II with anesthetics(S.T.T-II), Tear film break-up time(T.B.U.T) 등을 검사 하였다. 결과: 콘택트렌즈 착용여부에 따라 사무실 실내공기질이 안구건조증에 영향을 미치는 요인으로는 TSP는 $200{\mu}g/m^3$, $PM_{10}$은 $86.7{\mu}g/m^3$, 포름알데히드는 $0.4{\sim}1.0{\mu}g/m^3$을 기준으로 농도가 높게 측정되었을 때 유의한 관련성이 있는 것으로 분석되었다. 그러나 $CO_2$(p=0.146), 온도(p=0.074)와 습도(p=0.053)는 통계적으로 안구건조와 유의한 관련성이 없는 것으로 분석되었다. 결론: 사무실 재실자의 안구 건조에 $CO_2$ 및 온도, 습도는 유의한 영향이 없었으나, TSP, $PM_{10}$, 포름알데히드의 실내 농도와 콘택트렌즈의 착용여부는 관련이 있었다. 콘택트렌즈 착용에 대한 종합적인 관리와 사무실 실내공기의 개별적인 평가가 함께 이루어져야 하겠다.

• 국제학술발표논문집
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• The 2th International Conference on Construction Engineering and Project Management
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• pp.311-317
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• 2007

"Environmentally Sound and Sustainable Development (ESSD)" is a key word in recent years. The construction industry, have put a great influence on ergonomic and sustainable environment. Recently, "green building certifications", such as Indoor Air Quality (IAQ) and eco-friendly material regulation have been established. With this regard, new construction and aged-housing remodeling projects are required to meet these certification criteria. Multi-housing residents have great concern on eco-product, since many cases are reported that Sick Building Syndrome is caused by toxic substance from building materials. Aged-housing remodeling project is very unique in that building residents are selected prior to design phase. Therefore, the analysis of resident's need for building materials in aged-housing remodeling is relatively easy compared to new building construction. As such, it is very important to analyze their preferences for eco-friendly materials prior to project execution. The purpose of this study is to find the needs of residents and priority of their needs. Based on their needs and priority, this paper provides a new strategy in using environment-friendly materials and maximizing their satisfaction level when aged housing remodeling is constructed. In addition, this paper provide new criteria in selecting new developed environmental materials in remodeling projects for the purpose of improving the safety and health level in construction industry.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.919-924
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• 2008

Power consumption in the building thermal load could be the sum of the building fabric conduction load, building ventilation convection load and other such as radiation loss load. Dynamic Breathing Building (DBB) is the state-of-the-art to improve the wall insulation and indoor air quality(IAQ) performance as making air flow through the wall. This heat recovery type DBB contributes the power consumption saving due to the improved dynamic U-value. KIER twin test cell with static insulation(SI) and dynamic insulation(DI) at KIER was developed to test building power consumption at the real outside conditions. Then, the actual results were compared with the theory to predict the power consumption at the KIER twin test cell and introduced the building new radiation loss factor $\alpha$ to explain the difference between the both the theory and the actual case. As the results, the power consumption at the breathing DI wall building could saved 10.8% at the 2ACH(Air change per hour) compared with conventional insulation. The building radiation loss factor $\alpha$ for this test condition to calibrate the actual test was 0.55 in the test condition.

• 한국대기환경학회지
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• 제20권6호
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• pp.715-727
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• 2004

This study was carried out to evaluate non-smoker's exposure levels to environmental tobacco smoke (ETS) in the air of offices in urban areas. A total of 65 offices were selected from two large cities, i.e. Daegu and Daejeon. The field sampling was conducted repeatedly in summer (1999) and winter (1999～2000). The measured ETS markers included respirable suspended particles (RSP as PM$_{40}$ ), vapor and particulate phase ETS markers, including nicotine, 3-ethnyl pyridine (3-EP), ultraviolet absorbing particulate matter (UVPM), fluorescing particulate matter (FPM), and solanseol in ETS particles (SolPM). RSP was measured gravimetrically by a microbalance. The particle samples were then used for the determination of particulate ETS markers by HPLC, while vapor phase markers determined by GC/NPD. The analytical methods were validated for repeatability, linearity, detection limits, and duplication precision. The concentrations of RSP and other ETS markers were significantly higher in smoking offices than non-smoking offices. Despite the similar smoking strength in each office for different seasons, the concentration levels of ETS components appeared to be higher in winter than summer. The contributions of ETS to RSP concentrations based on SolPM, FPM, and UVPM methods were estimated to be in the range of 15.2 ～ 25.3% in smoking offices, whereas 2.4 ～ 15.9% in non-smoking offices. The cooling and heating types did not affect significantly the concentrations of RSP and other ETS markers. Finally, further research issues were suggested to obtain more scientific information on the non-smoker's exposure to ETS with respect to the frame of risk assessment..

• 한국축산시설환경학회지
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• 제18권1호
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• pp.25-34
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• 2012

1. 돈사의 유형별 시간대에 따른 공기품질의 변화패턴을 알아본 결과 돈사 실내의 온 습도, 먼지농도, 실내기체의 조성 등이 주간과 야간의 편차가 크게 나타났으며, 대부분의 돈사는 주간시간대인 12:00경의 실내 환경조건이 가장 양호하였고 00:00~06:00 사이의 공기조성이 가장 불량한 것으로 나타났다. 2. 돈사의 유형별 공기품질이 양호한 곳은 임신돈사와 분만돈사였으며, 불량한 돈사는 육성돈사와 비육돈사 이었다. 공기의 품질이 양호하였던 임신돈사의 경우, 슬러리 형태로서 분과 뇨의 분리가 잘 이루어진 결과였으며, 분만돈사의 경우는 돈사당 사육두수에 비하여 포유자돈의 배설량이 적었기 때문이었다. 반면, 공기품질이 불량한 육성돈사 및 비육돈사는 분뇨배설량이 많을 뿐 아니라 분뇨의 적체시간이 긴 구조적 특성이 작용한 결과였다. 또한 분만돈사의 경우, 심야시간대인 00:00 부터 06:00 사이에 일산화탄소와 이산화탄소의 함량이 크게 증가하는 현상을 보였는데 이것은 이 시간대의 공기품질이 자돈폐사율의 증가요인이 될 수 있음을 시사한다. 3. 그러므로 돈사의 환경을 개선하려면, 실내 악취발생을 최소화할 수 있는 시설구조, 적합한 사육밀도의 조절 및 자동감지 환기 시설 등이 매우 중요한 요소라고 하겠다.

• 설비공학논문집
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• 제19권1호
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• pp.94-131
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• 2007

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2004 and 2005 has been done. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD and flow visualization(PIV, PTV and LDV methods) technologies were widely applied for developing facilities and their systems. (2) The research trends of the previous two yews are surveyed as groups of natural convection, forced convection, electronic cooling, heat transfer enhancement, frosting and defrosting, thermal properties, etc. New research topics introduced include natural convection heat transfer enhancement using nanofluid, supercritical cooling performance or oil miscibility of $CO_2$, enthalpy heat exchanger for heat recovery, heat transfer enhancement in a plate heat exchanger using fluid resonance. (3) The literature for the last two years($2004{\sim}2005$) is reviewed in the areas of heat pump, ice and water storage, cycle analysis and reused energy including geothermal, solar and unused energy). The research on cycle analysis and experiments for $CO_2$ was extensively carried out to replace the Ozone depleting and global warming refrigerants such as HFC and HCFC refrigerants. From the year of 2005, the Gas Engine Heat Pump(GHP) has been paid attention from the viewpoint of the gas cooling application. The heat pipe was focused on the performance improvement by the parametric analysis and the heat recovery applications. The storage systems were studied on the performance enhancement of the storage tank and cost analysis for heating and cooling applications. In the area of unused energy, the hybrid systems were extensively introduced and the life cycle cost analysis(LCCA) for the unused energy systems was also intensively carried out. (4) Recent studies of various refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and of alternative refrigerants including carbon dioxide. Efficiency of various compressors and expansion devices are also dealt with for better modeling and, in particular, performance improvement. Thermoelectric module and cooling systems are analyzed theoretically and experimentally. (5) According to the review of recent studies on ventilation systems, an appropriate ventilation systems including machenical and natural are required to satisfied the level of IAQ. Also, an recent studies on air-conditioning and absorption refrigeration systems, it has mainly focused on distribution and dehumidification of indoor air to improve the performance were carried out. (6) Based on a review of recent studies on indoor environment and building service systems, it is noticed that research issues have mainly focused on optimal thermal comfort, improvement of indoor air Quality and many innovative systems such as air-barrier type perimeter-less system with UFAC, radiant floor heating and cooling system and etc. New approaches are highlighted for improving indoor environmental condition as well as minimizing energy consumption, various activities of building control and operation strategy and energy performance analysis for economic evaluation.