• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제21권2호
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• pp.103-108
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• 2009

Local exhaust system used in toilet and cooking place of low-rise public house installed roof ventilator at terminal of stack. There are many high riser public houses in Korea. These buildings were not viewed as being major contributors to exhaust pollutants producted in indoor. It was because many engineers thought that exhaust in high riser public house depends on stack effect. But Neutral pressure level represents in a terminal of stack with air tightness for the best exhaust efficiency. Thereby, lower floors have the worst indoor air quality. This paper focuses mainly on the exhaust efficiency improved by roof fan with motor installed in high riser public house. It is observed there is higher exhaust efficiency than the existing natural roof ventilator.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제16권7호
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• pp.652-657
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• 2004

Development of underground space in urban area has a huge amount of potential to ease the limitations on the land use and the efficiency especially in urban area. Considering public transportation in urban area, subway system could be one of the most efficient and practical approaches. Subsequently this leads the public to have more chances to experience the indoor air quality (IAQ) in subway systems. In this study, it was aimed to produce useful data for the IAQ control in subway environments, Specifically the train-induced wind has been investigated by means of field survey and analysis. The recent updates including the quantified characteristics of train-induced wind are presented in this paper.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• 제17권3호
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• pp.1-12
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• 2021

In this study, the effects of various operational conditions for floor radiant heating system were researched by experiments. Hot water supply set temperature, indoor air set temperature and supply water flowrate were considered as operational conditions. The control method for this system is On-Off control of automatic thermostatic valve. The purpose of this study is to evaluate indoor thermal control characteristics and energy performance, respectively. As a result, if lower supply water temperature is applied, the supply and return temperature difference is reduced and energy consumption of heat supply is also reduced.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 한국주거학회 2004년도 추계학술대회 논문집
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• pp.319-322
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• 2004

The purpose of this study is to evaluate the reduction effect of bake out on the concentration of indoor air pollutants by measuring the concentration of indoor pollutants(VOCs, HCHO) after the bake out. As a result of the study, bake out was considerably effective in reducing the concentration o( indoor air pollutants, showing relatively high reduction ratio around 40${\sim}$56%. However, continuous attention and control after the bake out is required for the prevention of the rise of the concentration by subsequent emission.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 한국대기환경학회 2007년도 추계학술대회 논문집
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• pp.550-551
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• 2007

• International Journal of Air-Conditioning and Refrigeration
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• 제10권4호
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• pp.211-219
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• 2002

In this study, in-situ performance test of a wet surface finned-tube evaporator of an air source heat pump which has a rating capacity of 20 RT is carried out. Since test conditions, such as indoor and outdoor air conditions cannot be controlled to satisfy the standard test conditions, experiments are done with the inlet air conditions as they exist. From the experimental data, air side heat and mass transfer coefficients were calculated by the well known heat and mass transfer analogy and tube-by-tube method. Since current procedure underpredicted the experimental sensible heat factor (SHF), a proper empirical parameter was introduced to predict the experimental data with satisfactory results. This study provides the method of evaluating the heat and mass transfer coefficients of a wet surface finned-tube evaporator of which in-situ performance test is necessary.

• Journal of the Korean Institute of Rural Architecture
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• 제22권1호
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• pp.1-12
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• 2020

The main purpose of the research is to prevent residents who are using underground parking lot from being exposed to pollusion, and to allow them to enjoy clean indoor environment. The study subject for the research are underground parking lots in 20 different apartments, 4 of them were constructed before 2000, 10 were constructed from 2000-2010, and the rest were constructed after 2010. By analyzing the air quality in these underground parking lots, we found out that O3, NO2, CO, PM10, Radon in all parking lots were not excessive compared to the standard limit. TVOC rate was measured with the value in between 312 ~ 2,137㎍/m3, with CO2 value in between 193~1,824 ppm, and HCHO with the value in between 0.01~1.52ppm. The lightning system in underground parking lots in apartments constructed before 2000 were using manual light control system, while automatic light control system was used in all apartments constructed after 2000, and the brightness of parking lots in apartments constructed before 2000 was quite low. The apartments constructed after 2000 are performing cleaning and ventilation due to management agreement, while the apartments constructed before 2000 are not performing regular cleaning and there was no mechanical ventilation system installed. The difference of indoor air quality was significant seasonally, daily, and yearly (year of construction), while illuminance was significantly different yearly.

• Journal of Bio-Environment Control
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• 제25권4호
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• pp.270-276
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• 2016

This study analysed overall heat transfer coefficient, heat transmission, and rate of indoor air heating provided by water curtain in order to determine the heat transfer characteristic of double-layered greenhouse equipped with a water curtain system. The air temperatures between the inner and outer layers were determined by the water flow rate and inlet water temperature. Higher water flow rate and inlet water temperature resulted in the increased overall heat transfer coefficient between indoor greenhouse air and water curtain. However, it was found that with higher levels of water flow rate and inlet water temperature, indoor overall heat transfer coefficient was converged about $10W{\cdot}m^{-2}{\cdot}^oC^{-1}$. The low correlation of overall heat transfer coefficient between water curtain and air within double layers was likely because the combination of greenhouse shape, wind speed and outdoor air temperature as well as water curtain affected the heat transfer characteristics. As water flow rate and inlet water temperature increased, the heat transferred into the greenhouse by water curtain also tend to rise. However it was demonstrated that the rate of heat transmission from water curtain into greenhouse with water curtain system using underground water was accounted for 22% to 28% for total heat lost by water curtain. The results of this study which quantify heat transfer coefficient and net heat transfer from water curtain may be a good reference for economical design of water curtain system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제13권11호
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• pp.1072-1078
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• 2001

The real time optimal control algorithm of the DDC controller for chilled water and supply air temperature set-point of heating, ventilating, air-conditioning and refrigeration systems has been researched for minimization of the total power which is consumed by the chiller, chilled water pump and air handing unit fan. The study has been done by using TRNSYS program in order to analyze the central cooling system in terms of the environmental variables such as indoor cooling lead and wet-bulb temperature. This optimal control alogorithm saves more energy and is suitable for real time on-line control in comparison with conventional method.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제12권9호
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• pp.810-816
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• 2000

Thermal comfort plays an important role in modern office buildings. Four major factors affecting thermal comfort are air temperature, velocity, humidity and radiation temperature. Distribution of these thermal factors in indoor space depends largely on the air flow which is related to the method of supplying and extracting air. In this study, an experimental analysis on indoor thermal comfort is conducted to study the difference between a ceiling supply cooling system and a floor supply one. The two cooling systems are applied to an office space during summer season and the distributions of temperature, velocity, radiation temperature and PMV are measured. Results show that the floor supply cooling system is superior in terms of thermal comfort and energy saving. Studies need to be done, however, to reduce the vertical temperature difference of a floor supply air conditioning system.