• Journal of Korean Society for Atmospheric Environment
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• v.23 no.E2
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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.

• Journal of the Korean housing association
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• v.16 no.1
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• pp.73-79
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• 2005

The ventilation efficiency of apartment housing bathroom has been measured by the flexible's diameter, length, and installation format to the exhaust In. The gas density attenuation method of Tracer Gas Method has been specifically utilized for this measurement. Full size mock-up of apartment housing bathroom, which was approximately $100 m^2$ in size, has been established for the ventilation emciency measurement. In addition, the ventilation efficiency has been studied by the possibility of air-supply In. The diameters of flexible are 100 mm, 125 mm, and 150mm. It also have the length of 1.0m, and 1.5 m. The installation formats are I shape, L shape, and S shape. As a result of this measurement, the flexible which has the highest ventilation efficiency was the one has bigger diameter, short in length, and I shape installation format.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2001.11a
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• pp.77-82
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• 2001

This paper is contents that measure the ventilation rates and temperature by driving condition of exhaust fan, vapor, contaminant occurrence amount of carbon dioxide etc. In kitchen of apartment house. The ventilation rates in the apartment kitchen measured by Tracer Gas Method. And, temperature of when cook by gas table hood lower part 10cm and floor upside 10cm of kitchen central part, 120cm, 210cm heights measure. As ventilation rates measurement result, ventilation number of times was 0.7(number of times/hour) when did not to operate exhaust fan. but we were measured by 2.3(number of times/hour) when drove strongly. As temperature measurement result at cooking by gas table, temperature showed highest in hood lower part 10cm of case that do not operate exhaust fan. Temperature at kitchen central was most low in 10cm height in talc floor, and 210cm were measured highest. Concentration of carbon dioxide is very high by 4,350ppm after measurement time 10 minutes in state who do not operate exhaust fan at cooking by gas table.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.547-551
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• 1998

Reaeration coefficient is the physical absorption of oxygen from the atmosphere by water. It is the most important natural means by which a stream replaces the oxygen consumed in the biodegradation of organic wastes, and the rate constant describing this process is the reaeration coefficient, It. Reaeration coefficient is the dominant parameter affecting the use of water quality model. Therefore accurate estimation of the reaeration coefficient is essential for optimum water quality management. There is several method to estimate stream reaeration coefficient. In this study, it would be concluded that SI-peak method is of practical use when applied to small stream, and CRI method is adequate to large stream.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.9
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• pp.506-515
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• 2013

The PFT (PerFluorocarbon Tracergas Technique) is of advantage to field surveys for evaluating the ventilation condition, due to its simplicity and convenience. On the other hand, it requires researchers to make some additional considerations that include uncertainties, such as the substance concentration distribution in indoor air, representativeness of a sampler, deviation of emission sources, and analysis error. In this study, the PFT and $CO_2$ tracer gas methods were applied simultaneously, to evaluate the accuracy of PFT on six ventilation conditions in the three-storied detached house. The air exchange and the outdoor air introduction a between and into zones were measured. As the results, deviations of PFT concentration distributions were observed at a sufficiently low level for an accurate determination for a house where the interior height was large, and there were relatively many partition walls. However, when a uniform airflow appeared in the indoor air, it was also validated that the indoor air would be exhausted without sufficient mixing, and consequently the measurement error of the PFT would be large.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.944-949
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• 2006

An infiltration was realized as an important part of ventilation to change fresh air with contaminated air in a house. In this study, it was measured the infiltration in new apartment buildings according to Seasons, height etc. We measured the infiltration by using tracer gas method and did for 24hours. To quantify the infiltration, Sulfur Hexafluoride($SF_6$) gas was used. The Constant Concentration was conducted during experimental process and the concentration of the gas was measured with a gas monitor. In the results of the measurement, the infiltration were appeared over 0.6 ACH in winter and about 0.2 ACH in summer and autumn. Also the infiltration were measured more highly at high and low stories than middle stories in winter.

• Journal of Soil and Groundwater Environment
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• v.16 no.5
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• pp.42-52
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• 2011

In this laboratory study, the changes in gas-exposed perchloroethene (PCE) saturation in sand during a PCE removal process were measured using gaseous tracers. The flux of fresh air through a glass column packed with PCEcontaminated, partially water-saturated sand drove the removal of PCE from the column. During the removal of PCE, methane, n-pentane, difluoromethane and chloroform were used as the non-reactive, PCE-partitioning, water-partitioning, and PCE and water-partitioning tracers, respectively. N-pentane was used to detect the PCE fraction exposed to the mobile gas. At water saturation of 0.11, only 65% of the PCE was found to be exposed to the mobile gas prior to the removal of PCE, as calculated from the n-pentane retardation factor. More PCE than that detected by n-pentane was depleted from the column due to volatilization through the aqueous phase. However, the ratio of gas-exposed to total PCE decreased on the removal of PCE, implying gas-exposed PCE was preferentially removed by vaporization. These results suggest that the water-insoluble, PCE-partitioning tracer (n-pentane in this study), along with other tracers, can be used to investigate the changes in fluid (including nonaqueous phase liquid) saturation and the removal mechanism during the remediation process.

• Journal of the Korean Institute of Gas
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• v.16 no.2
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• pp.31-37
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• 2012

This paper describes to analyze the ventilation performance of a room air conditioner for indoor comfort control. An experimental apparatus consists of a test room, the room air conditioner, a tracer gas measurement system, a supply fan and a controller. Ventilation performance as a function of human occupancy is evaluated with supply ventilation air using a tracer gas technique of CO2 gas in the test room. The ventilation performance is evaluated in a step-down method based on ASTM Standard E741-83 and is found to increase with increasing supply ventilation rate. The CO2 gas concentration is decayed rapidly without human occupancy. The ventilation performance without human occupancy increases up to 55% and the ventilation performance with one person increases up to 25% at the supply air of 570 lpm comparing with a natural reduction after one hour. A modeling for ventilation performance of a room air conditioner in a test room is presented using experimental datum.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.219-222
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• 2014

The flame chemiluminescence is a good tracer of flame statement. In this study, the characteristics of flame chemiluminescence($OH^*$, $CH^*$, ${C_2}^*$) according different measuring locations using photomultiplier(PMT), spectrometer and CCD camera. Measurements are made for $OH^*$, $CH^*$, ${C_2}^*$ radicals in gas & light oil diffusion flames. At turbulent nonpremixed combustion mode, the equivalence ratio is varied. The experimental results showed that measuring location affects the result of flame chemiluminescence.

• Journal of Mechanical Science and Technology
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• v.19 no.4
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• pp.1001-1005
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• 2005

This paper evaluates the performance of ventilation for the removal of indoor pollutants as a function of ventilation rate and the number of occupants in a test room and school classroom. An experimental apparatus consists of a test room, a tracer gas supply system, a gas detector, and a fan for ventilation air supply with a controller. The ventilation performance is evaluated in a step-down method based on ASTM Standard E741-83 using $CO_{2}$ gas as a tracer gas in the test room of 35 $m^{3}.$ For the ventilation air flow rate of 1.0 ACH, a recommended ventilation flow rate of Korea school standard for acceptable indoor air quality in the case of one person, CO_{2}$ gas concentration decreases up to $55{\%}$ within 50 minutes without occupancy and increases up to $75{\%}$ in the case of one occupant. Also indoor air quality at the school classroom is investigated experimentally.