• 설비공학논문집
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• 제13권8호
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• pp.682-691
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• 2001

Most of radiant floor heating systems are operated in the intermittent heating mode in Korea. The application possibility of predictive suboptimal control for Koran residential house was investigated by computer simulation and experiment. For this study, TRNSYS program was used and an experimental facility consisting of tow rooms ($3\times4.4\times2.8 m$) identical in construction was built. The facility enabled simultaneous comparison of two different control method. And real multi residential hose was investigated. Results showed that outdoor air temperature prediction control was superior to the conventional control for radiant floor heating system operated in the intermittent heating mode. New control system resulted in good thermal environment and les energy consumption.

• 설비공학논문집
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• 제21권11호
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• pp.599-605
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• 2009

This paper presents a numerical evaluation of the flow rate of air conditioner outdoor unit by investigating the effects of fan location and shroud shape. To determine optimal design parameters, we investigated the exhaust flow rate by changing shroud height, fan height, fan guide height, and fan width. The 3rd order central composite design was performed to select three most important parameters affecting the exhaust flow rate. According to the result of response surface method, the exhaust flow rate of the optimum model increased by 6.25% compared to that of the base model.

• 설비공학논문집
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• 제23권5호
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• pp.334-341
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• 2011

In the present study, optimal heat supply algorithm which minimize the heat loss through the distribution pipe line in group energy apartment was developed. Variation of heating load of group energy apartment building in accord with the outdoor air temperature was predicted by the heating load-outdoor temperature correlation. Supply water temperature and mass flow rate were controlled to minimize the heat loss through distribution pipe line. District heating apartment building located in Hwaseong city, which has 1,473 households, was selected as the object building for testing the present heat supply a1gorithm. Compared to the previous heat supply system, 10.4% heat loss reduction can be accomplished by employing the present method.

• 한국태양에너지학회 논문집
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• 제34권4호
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• pp.31-38
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• 2014

This study makes three apartment building complex an object of analyzing representative building types and energy consumption rate of house holds, and effect of outdoor air cooling. Recently created apatrment complex is composed of very various types of building, plan, and orientation etc. But, it is difficult to remark conclusively that these various types of buildings are designed energy-effectively. Because architects are hard to find useful energy design guideline for decision making. By the preceding study, the present condition and problem about this subject is grasped, apartment building types were examined and representative types were extracted. In this study, energy simulation was conducted, and the effect to outdoor air cooling was analyzed about representative types of the subject apartment complex. It is expected that this analysed results will be basic data for the more integrated study. Research consequence can be summarized as follow: 1) Besides solar gain, household layout of building, orientation, and plan etc. effects compositively on energy consumption rate. 2) The effect of ourdoor air cooling in building of tower type can be improved by arranging households appropriately.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1337-1342
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• 2009

This test was progressed in the test house of KICT as sectional research of Center for Sustainable Housing. It included a ventilation rate of hybrid ventilation equipment, temperature, and gas test using the SF-6. The purpose of this test is to demonstrate the performance of viovent by estimating an outdoor air flow rate through viovent which the flimmer filter is installed and decide the leakage after operating the constant airflow fan within a house. First, the outdoor airflow rate through viovent measured $130\;m^3/h$ more than a legal required ventilation rate, $104\;m^3/h$. And then it sufficiently satisfy a legal standard, 0.7 air change/h. Secondly, the result of this test exposes that the leakage in the residence is about $20{\sim}25%$. Especially, the outdoor air flowing through the gate occupies 50% of the total leakage.

• 설비공학논문집
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• 제23권11호
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• pp.726-732
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• 2011

The aerodynamic and aeroacoustic performance of discharge grille of outdoor unit of air-conditioner was investigated in this study. Discharge grille is one of outdoor unit's important parts to affect the flow rate and Overall Sound Pressure Level(OSPL). New type of discharge grille was suggested based on the results of numerical simulation. To simulate the flow pattern near the propeller fan, commercial flow solver FLUENT was used. Sliding mesh method was used for rotating propeller fan and initial condition for unsteady model was calculated by Multiple Reference Frame(MRF) method. To minimize the interaction noise between fan blade wake and discharge grille, new discharge grille has radial rib which is aligned with trailing edge of fan blade. And inclined radial rib was adopted for reducing flow rate drop in discharge grille. The optimization of inclined angle of radial grille was performed experimentally.

• 한국태양에너지학회 논문집
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• 제34권1호
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• pp.72-80
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• 2014

This study proposed a wind power generation system utilizing outdoor air on the rooftop and indoor ventilation, which would increase according to the building height, as a way to help to save energy consumption in a building by using wind power energy of the new renewable energy sources. The study measured the distribution of air currents and power generation according to the usage factor of exhaust pipes in the kitchen and bathroom and identified the elements to consider when applying a wind power generation system to buildings in order to use outdoor air on the rooftop increasing according to the height and the indoor ventilation produced in the facility vertical shafts inside the buildings by installing a wind power generation system on the rooftop. (1) The study measured the ventilation velocity of the kitchen hood and bathroom ventilation fan by changing the zone areas by the households according to the usage factor of [${\alpha}$]=33~100%. As a result, the kitchen ventilation pipe generated the ventilation wind of 3.0m/s or more at the usage factor of [${\alpha}$] 66% or higher, and the bathroom ventilation pipe generated ventilation velocity lower than 3.0m/s, the blade velocity of the wind power generator, even after the usage factor rose to [${\alpha}$]=100%. (2) As the old bathroom ventilation pipe generated the ventilation velocity of 3.0m/s, the blade velocity of the wind power generator, even with the rising usage factor [${\alpha}$], the application of an outdoor air induction module increased the ventilation velocity by 2.9m/s at the usage factor of [${\alpha}$]=33%, 3.8m/s at the usage factor of [${\alpha}$]=66%, and 3.6m/s at the usage factor of [${\alpha}$]=100%. Thus the ventilation velocity of 3.0m/s, the blade velocity of the wind power generator, or higher was secured. (3) The findings prove that the applicability of a wind power generation system using outdoor air on the rooftop and indoor ventilation is excellent, which raises a need for various efforts to increase the possibility of its commercialization such as securing its structural stability according to momentary gusts on the rooftop and typhoons in summer and making the structure light to react to the wind directions of outdoor air on the rooftop according to the seasons.

• 한국대기환경학회지
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• 제6권1호
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• pp.73-84
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• 1990

The study was carried out to investigate the extent of indoor air pollution in living rooms of apartment houses(residential area) and offices(traffic area A : no smoking space, B : smoking space) in Seoul and to determine the health significance of indoor air pollution. Indoor and outdoor concentrations of major air pollutants were observed simultaneously from February 13 to 17, and July 24 to 28, 1988. The concentrations of carbon monoxide(CO), nitrogen oxides(NOx), sulfur dioxide($SO_2$), carbon dioxide($CO_2$) and total suspended particulate(TSP) in living room and offices were measured and the results were summarized as follows: 1. Both in summer and in winter, the indoor concentrations of CO, $CO_2$, and TSP in offices were higher than the outdoor concentrations, on the other hand, $SO_2$ was higher in the outdoors and NOx was lower than the outdoor concentration only in office A where smoking is not permitted. 2. The indoor and outdoor pollution of offices in winter was significantly higher than that in summer, and the concentrations of CO, NOx and $SO_2$ in indoor and outdoor air in living room in winter were also higher than those in summer. These results suggest that indoor levels of air pollutants are affected by smoking and winter heating systems.

• 설비공학논문집
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• 제14권3호
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• pp.240-246
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• 2002

Bypass air conditioning systems are divided into three types; an outdoor air bypass, a mixed air bypass and a return air bypass system. What makes the return air by pass system more effective is that it directs all of moist outdoor air through the cooling coil. The bypass air conditioning system can maintain indoor R.H (Relative Humidity) less than a conventional CAV (Constant Air Volume) air conditioning system by adjusting face and bypass dampers at part load. When a design sensible load (the ratio of sensible load to total sensible load) is 70 percent (at this time, RSHF (Room Sensible Heat Factor) . 0.7), indoor R.H was maintained 59 percent by the return air bypass system, but 65 percent by the conventional CAV air conditioning system (valve control system). The bypass air conditioning system can also improve IAQ (Indoor Air Quality) in many buildings where the number of air change is high.

• 설비공학논문집
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• 제27권3호
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• pp.137-145
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• 2015

In this study, the actual energy consumption of the secondary side of District Heating System (DHS) with different hot water supply temperature control methods are compared. Three methods are Set-point Control, Outdoor Temperature Reset Control and Outdoor Temperature Prediction Control. While Outdoor Temperature Reset Control has been widely used for energy savings of the secondary side of the system, the results show that Outdoor Temperature Prediction Control method saves more energy. In general, Outdoor Temperature Prediction Control method lowers the supply temperature of hot water, and it reduces standby losses and increases overall heat transfer value of heated spaces due to more flow into the space. During actual energy consumption monitoring, Outdoor Temperature Prediction Control method saves about 7.1% in comparison to Outdoor Temperature Reset Control method and about 15.7% in comparison to Set-point Control method. Also, it is found that at when partial load condition, such as daytime, the fluctuation of hot water supply temperature with Set-point Control is more severe than Outdoor Temperature Prediction Control. Therefore, it proves that Outdoor Temperature Prediction Control is more stable even at the partial load conditions.