• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.135-140
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• 2005

Installation of ceiling type unit is achieved by one of efforts for agreeable classroom environment embodiment along with economic growth. But research about changing the position of ceiling type unit is lacking in present. Therefore, this thesis is to study the thermal environment of 5 different position cases of ceiling type, namely Case A, B, C, D, E. Here, Case C is the case that has the position of ceiling type center of the classroom and the other 4 alternatives are 0.7 m away from the Case C according to x and z axis. In this thesis temperature distributions, air current distribution, heat amenities such as PMV of occupants are analyzed as the environmental factors. Through these factors, Case C and Case D are the better position alternatives than the alternatives of Case A, Case B and Case E because the latter cases the air current reaches directly to indoor occupants so that occupants feel chilly. This thesis has a conclusion under the condition of only one inlet air temperature and seat arrangement. But afterwards more inlet air condition and seat arrangement must be considered.

• 설비공학논문집
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• 제15권8호
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• pp.683-689
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• 2003

The thermal comfort of an indoor swimming pool is different from that of general indoor space because of the characteristics of large space and the wear conditions of swimmers. Dew condensation by humid air not only makes mold on the floor, wall and roof but also decreases the durability of buildings by penetrating into their structures. In this study, the characteristics of the flow field, the temperature field and the humidity distribution in an indoor swimming pool have been examined by the numerical method to estimate the level of thermal comfort and the generation rate of dew condensation. The results showed that the dew condensation regions were spread widely at the eastern parts of the swimming pool due to the insufficient air flow rate with low velocity and temperature. To prevent the generation of dew condensation in a region, a sufficient warm air flow rate should be supplied to make an air mixing. The values of PMV at horizontal plane of 1.5 m height have the range of -1.0∼1.2, which means the suitable level for swimmers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.145-147
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• 2005

This paper presents a methodology for satisfying the thermal comfort of Indoor environment and reducing the summer peak demand power by minimizing the power consumption for an Air-conditioner within a space. KEPCO(Korea Electric Power Corporation) use the fixed duty cycle control method regardless of the indoor thermal environment. This method has disadvantages that energy saying depends on the set-point value of the Air-Conditioner and DLC has no net effects on Air-conditioners if the appliance has a lower operating cycle than the fixed duty cycle. A variable duty cycle estimates the PMV(Predict Mean Vote) at the next step with a predicted temperature and humidity coming from the back propagation neural network model. It is possible to reduce the energy consumption by maintaining the Air-conditioner's OFF state when the PMV lies in the thermal comfort range. The proposed methodology uses the historical real data of Sep. 7th, 2001 from a classroom in seoul to verify the effectiveness of the variable duty cycle method comparing with fixed duty cycle. The result shows that the variable duty cycle reduces the peak demand to 2.6times more than fixed duty cycle and increases the load control ratio by 8% more. Based on the variable duty cycle control algorithm, the effectiveness of DLC is much more improved as compared with the fixed duty cycle.

• 한국환경농학회지
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• 제37권4호
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• pp.268-276
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• 2018

본 연구는 일반인에게 안전한 실내공기질 개선수단으로 인식되는 공기정화식물의 효율적 적용을 위해 실내공조에 요구되는 총풍량 확보가 가능한 식생기반 바이오필터 시스템을 제안하고자 했다. 시스템의 정량적 성능평가는 강의실형태의 실험실 체적 $332.73m^3$ 내 16명의 재실자 조건에서 목업단위 시스템의 공조 성능, 실내공기질 및 쾌적지표 개선효과에 대한 시계열 분석으로 진행되었다. 우선, 시스템 구동을 통해 총 $1,411.22m^3/h$의 유출 총풍량을 확보하여, 4.24 ACH의 환기율을 제공할 수 있었다. 실내온도는 $1.6^{\circ}C$, 흑구온도는 $1.0^{\circ}C$ 감소가 확인되었으며, 상대습도는 24.4% 상승한 최대 82.0%까지 증가하였다. 상대습도 급증에 따른 쾌적도 감소현상은 송풍기 구동에 따라 발생되는 실내기류로 상쇄되는 것으로 판단된다. 또한, 시스템 가동에 따른 공기질 개선지표 중 $PM_{10}$은 39.5% 감소한 평균 $22.11{\mu}g/m^3$을 기록하였다. 반면, $CO_2$는 최대 1,329 ppm까지 지속적으로 농도가 상승했는데, 이는 광도조건이 광보상점을 만족하지 못해 적용 식물과 재실자에서 방출되는 $CO_2$가 처리되지 못한 것으로 해석된다. 실내쾌적지표의 경우 PMV는 평균 83.6 % 감소된 -0.082, PPD는 평균 47.0% 감소된 5.41%에 수렴하여 식생기반 바이오필터 구동에 의해 높은 쾌적범위의 실내공간조성이 가능한 것으로 판단되었다. 본 연구의 한계는 소수 참여인원과 단기간 실험으로 인하여 시스템의 성능 규명이 제한적인 부분이었으며, 보다 장기간의 실험을 통해 바이오필터에 도입된 식생의 생육상태에 따른 압력손실 변화, 미세먼지 저감에 대한 구체적인 메커니즘 규명 등의 후속연구가 진행되어야 할 것이다.

• Architectural research
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• 제19권3호
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• pp.71-77
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• 2017

Dynamic pricing refers to a system in which a tariff varies, according to a level of charging and applied time depending on time change. The power billing system used in the Korean Electric Power Corporation (KEPCO) is based on time of use (TOU) pricing, which is one of the dynamic pricing systems. This paper aimed to determine the operational results of a variable refrigerant flow system, to which a new control algorithm was applied, in order to respond to dynamic pricing, in summer and the utility of the new control. To do this, real measured data was acquired from a VRF system installed in a building for educational purposes, where dynamic pricing was applied for about 100 days during summer time. At the maximum load operation time period in TOU, the new control minimized operation within the indoor comfort range, an increase in refrigerant evaporation temperature in the indoor unit and the number of revolutions in a compressor in the outdoor unit was limited. As a result, power usage was decreased by 11%, and the operational cost by 14.6%. Furthermore, measurement results using the Predicted Mean Vote (PMV) model, that represented satisfaction of thermal environment, showed that 82.8% to 90.4% of the occupants of the building were satisfied during operation when the new control was applied.

• 대한기계학회논문집A
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• 제38권9호
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• pp.979-988
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• 2014

자동차를 이용하는 시간이 늘어남에 따라 자동차 실내의 온열쾌적성에 대한 관심이 급증하고 있다. 그러나 아직까진 실제 자동차 중에서 공조시스템의 냉방성능은 자동차 제조사별로 온열쾌적성 지표를 통해 평가되지 않고, 실내의 공기 속도와 온도 등 열환경 기준에 의해 평가되고 있다. 또한 차 실내의 온열쾌적성을 수치해석으로 평가하는 경우 타당한 결과를 도출할 수 있는 수치기법에 대한 기준이 확립되지 않은 상황이다. 본 연구에서는 외부 열원을 모사하기 위하여 태양광선 추적모델을 사용하고, 공조시스템 작동 후 20 분까지 다양한 매개변수(공조시스템의 작동모드와 작동풍량, 인체모델 탑승조건)에 대한 자동차 실내의 온열쾌적성 평가를 수행하였다. 이를 통해 자동차 실내의 온열쾌적성 지표를 예측할 수 있는 평가모델을 도출하였다.