• KIEAE Journal
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• 제13권2호
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• pp.39-46
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• 2013

Recently, the field of construction is putting a variety of effort into reducing CO2, since global warming is being accelerated due to climate changes and the increase of greenhouse gas. For reduction of CO2 in the field of construction, it is required to make plans to cut down heating energy of buildings and especially, it is urgently needed to cut down energy of residential buildings in rural area where occupies the majority of consumption of petroleum-based energy sources. Therefore, this research compared and analyzed the actual energy consumption, by evaluating energy performance of a detached house applying passive house design components for reduction of energy. As the result, energy consumption showed remarkable differences, according to the operation of a heat recovery ventilation unit which is one of passive house design components, and building energy consumption displayed remarkable differences, too, depending on the difference of airtightness performance during building energy simulation conducted in process of design. Based on these results, the importance of airtightness performance of passive house was verified. The result of the actual measurement of energy consumption demonstrated that LNG was most economical amongst several heat resources yielded, on the basis of LPG source energy consumption measured within a certain period of time, and it was followed by kerosene. LPG was analyzed to have a low economic efficiency, when used for heating.

• KIEAE Journal
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• 제14권3호
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• pp.71-77
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• 2014

This study aimed at developing and evaluating performance of the two logics for respectively operating two-position- and variable-heating systems. Both logics control the heating system and openings of the double skin facade buildings in an integrated manner. Artificial neural network models were applied for the predictive and adaptive controls in order to optimally condition the indoor thermal environment. Numerical computer simulation methods using the MATLAB (Matrix Laboratory) and TRNSYS (Transient Systems Simulation) were employed for the performance tests of the logics in the test module. Analysis on the test results revealed that the variable control logic provided more comfortable and stable temperature conditions with the increased comfortable period and the decreased standard deviation from the center of the comfortable range. In addition, the amount of heat supply to the indoor space was significantly reduced by the variable control logic. Thus, it can be concluded that the optimal control method using the artificial neural network model can work more effectively when it is applied to the variable heating systems.

• 한국환경과학회지
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• 제19권1호
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• pp.9-16
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• 2010

This pilot study evaluated fueling feasibility of sewage sludge, which contains a large amount of water content, by applying melting of thermoplastic polyethylene (PE). This study has identified a simultaneous achievement of drying and heating value improvement of the sewage sludge. The sewage sludge collected from a sewage sludge treatment plant during a winter period had a water content of 83.7 wt%, a combustible volatile content of 12.5 wt%, and an ash content of 3.8 wt%. The higher heating value (HHV) of the dried sewage sludge, before impregnation or coating of PE, was 4,600 kcal/kg. The collected sewage sludge was immersed into the melted PE solution, which had a HHV of 11,070 kcal/kg, and kept immersing with increasing reaction time. As the reaction (immersing or coating or impregnation) time increased, the water content of the sludge decreased. However, the HHV of the sludge increased with increasing the reaction time. The HHVs of the sewage sludge immersed or dipped into the melted PE solution for 15 min ranged from 6,780 to 8,170 kcal/kg with water content less than 7 wt%. This result indicates the melted PE solution can be utilized as an improvement technology for dryness and heating value of the sewage sludge with high water content. The sewage sludge impregnated or coated with melted PE can be utilized as potential fuel or energy resources.

• 한국태양에너지학회 논문집
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• 제38권5호
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• pp.37-47
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• 2018

The heating performance of a solar thermal seasonal storage system applied to a glass greenhouse was analyzed numerically. For this study, the gardening 16th zucchini greenhouse of Jeollanam-do agricultural research & extension services was selected. And, the heating load of the glass greenhouse selected was 576 GJ. BTES (Borehole Thermal Energy Storage) was considered as a seasonal storage, which is relatively economical. The TRNSYS was used to predict and analyze the dynamic performance of the solar thermal system. Numerical simulation was performed by modeling the solar thermal seasonal storage system consisting of flat plate solar collector, BTES system, short-term storage tank, boiler, heat exchanger, pump, controller. As a result of the analysis, the energy of 928 GJ from the flat plate solar collector was stored into BTES system and 393 GJ of energy from BTES system was extracted during heating period, so that it was confirmed that the thermal efficiency of BTES system was 42% in 5th year. Also since the heat supplied from the auxiliary boiler was 87 GJ in 5th year, the total annual heating demand was confirmed to be mostly satisfied by the proposed system.

• 대한건축학회연합논문집
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• 제20권6호
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• pp.113-119
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• 2018

Occupancy-based heating control is effective in reducing heating energy by preventing unnecessary heating during unoccupied period. Various technologies on detecting human occupancy have been developed using complicated machine learning algorithm and stochastic methodologies. This study aims at deriving low-cost and simple algorithm of occupancy inference that can be implemented to residential buildings. The core concept of the algorithm is to combine the occupancy probabilities based on indoor CO2 concentration and PIR(passive infrared) signals. The probability was estimated by applying different levels of decrement ratio depending on CO2 concentration change rate and aggregated PIR signals. The developed algorithm was validated by comparing the inference results with the occupancy schedule in a real residential building. The results showed that the inference algorithm can achieve the accuracy of 75~99%, which would be successfully implemented to the control of residential heating systems.

• 한국환경농학회지
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• 제2권2호
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• pp.114-119
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• 1983

채소(菜蔬)의 시설재배(施設栽培)에서 이상한파(異常寒波) 또는 보온(補溫) 및 가온열량(加溫熱量)의 불족(不足)으로 발생(發生)되는 저온장해(低溫障害)를 방지(防止)하고자 파라핀양초, 석유(石油)램프 및 전열선(電熱線)을 공시(供試)하여 보조가온(補助加溫) 시험(試驗)을 수행(遂行)한 결과(結果)는 아래와 같다. 1) 파라핀양초와 전열선(電熱線) 공중가설(空中架設)에 의(依)한 보조가온방법(補助加溫方法)으로 시설내(施設內)의 야간(夜間) 최저기온(最低氣溫) 강하(降下)를 방지(防止)할 수 있었다. 2) 파라핀양초와 전열선(電熱線) 보조가온(補助加溫)은 딸기에 장해(障害)를 보이지 않았고 생육(生育), 개화(開花), 수확(收穫)의 조기화(早期化)를 현저(顯著)히 촉진(促進)하였으나 총수량(總收量)의 증가(增加)는 인정(認定)되지 않았다. 3) 석유(石油)램프 보조가온(補助加溫)은 식물체(植物體)에 gas장해(障害)가 심(甚)하고 점등(點燈)과 소등(消燈)에 노력(努力)이 많이 들어 실화(失火)의 위험(危險)이 많고 연소(燃燒)에 의(依)한 악취(惡臭)가 심(甚)하여 가온재(加溫材)로서는 불적당(不適當)하였다. 4) 파라핀양초 보조가온(補助加溫)은 기상(氣象)의 예측(豫測)이 불정확(不正確)하므로 연료(燃料)의 낭비(浪費) 또는 가온열량(加溫熱量)이 불족(不足)한 경우(境遇)도 있으나 가온(加溫) 소요회수(所要回數)가 적을 때에 효과적(效果的)으로 사용(使用)할 수 있었다. 5) 전열선(電熱線) 보조가온(補助加溫)은 설치(設置)에 비용(費用)과 노력(努力)이 소요(所要)되나 온도(溫度)의 자동조절(自動調節)과 항온유지(恒溫維持)가 가능(可能)하므로 가온(加溫) 소요회수(所要回數)가 많을 때에 효과적(效果的)인 것으로 판명(判明)되었다.

• Environmental Analysis Health and Toxicology
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• 제14권1_2호
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• pp.35-43
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• 1999

A number of disinfection by-products (DBPs) are formed as a result of the addition of chlorine into the public water supply and some of them have been suggested to cause adverse health effects on humans. However, the estimation of human ingestion exposure to each DBP has been performed simply by multiplying the concentration of a chemical in the cold tap water by the volume of water consumed during a given period of time. However, a questionnaire concerning water consumptions administered to sixty people residing in Chunchon showed that the volume of tap water consumed accounted for approximately 70% of the total volume of water consumed and that of heated water represented approximately 94% of tap water ingested. Heating durations for water-containing foods (e. g., soups and pot stews) and heated beverages (e. g., barley tea) were grouped into 10, 20, 30, and 35 minutes. Based on these time frames, an aluminum pot containing one liter of tap water was heated for the above respective time periods using a gas range to determine the variations of the concentrations of individual DBPs by heating. The pH and total residual chlorine were measured before and after heating. Collected water samples were carried to the laboratory and analyzed for eight DBPs and total organic carbon. Chloroform, bromodichloromethane, chloral hydrate, 1, 2-dichloro-2-propanone, 1, 1, 1-trichloropropanone, and dichloroacetonitrile were not detected following heating for 10 minutes and longer. The concentration of dichloroacetic acid (DCAA) was elevated with heating duration, resulting in the averages of 2.0, 3.1, 4.7, and 12 times the initial concentration, respectively, for 10, 20, 30, and 35 minute heating periods. On the other hand, the concentration of trichloroacetic acid (TCAA) decreased with heating duration, with 0.65, 0.40, 0.34, and 0.19 times lower than the initial concentration. Therefore, it is suggested that ingestion exposure to DCAA increases with heating duration but that ingestion exposure to TCAA decreases. In addition, while the amount of DCAA was elevated at the initial time periods (10 or 20 minutes) and then slowly decreased, that of TCAA was rapidly decreased. In conclusion, water-heating processes during cooking influence the concentrations of individual DBPs in the tap water, with lower levels for volatile DBPs and TCAA, and higher levels for DCAA. Therefore, concentration change needs to be taken into consideration in the estimation of human ingestion exposure to DBPs.

• 대한기계학회논문집B
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• 제36권8호
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• pp.803-809
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• 2012

지역난방 시스템의 최적 스케쥴 제어를 위해서는 난방부하 예측이 필요하다. 공동주택의 난방부하는 복잡한 변수들의 영향을 받기 때문에 손쉬운 난방부하 예측을 위해 사용하기 쉬우며 효용성 있는 예측방법의 개발이 필요하다. 본 연구에서는 익일의 시간별 난방부하를 예측하기 위해 단순화된 외기조건 예측방법과 부하 예측방법을 제안하였다. 난방부하 예측을 위해 건물설계서에서 쉽게 얻을 수 있는 간단한 사양과 예측된 온습도가 사용되었다. 제안된 방법의 타당성을 검증하기 위해 지역난방 시스템으로부터 시간별로 실측된 난방부하와 예측된 결과를 비교하였다. 예측된 외기조건은 실측된 값과 비교하여 변화양상이 잘 일치하였다. 예측된 난방부하와 측정된 난방부하를 비교한 결과, 시간별, 일별, 월별 모두 예측과 실측이 비교적 잘 일치하였으며, 난방기간 동안 월별 부하의 평균 오차는 약 4.68%로 비교적 작은 값을 가졌다.

• 아시안잔디학회지
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• 제23권2호
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• pp.279-286
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• 2009

빌딩에서 발생하는 폐열을 활용할 목적으로 동절기 옥상정원에서 푸른 잔디를 유지하기 위한 잔디생육시험을 실시하였다. 옥상정원 지반에 Heating system을 설치하여 시기별 잔디생육상태를 조사한 결과는 다음과 같다. 겨울철 옥상녹화 지반을 heating처리한 결과, 무처리구에 비해 잔디품질 및 피복률이 우수하였으며, 잔디의 뿌리길이, 잔디밀도가 모두 상승하였다. 표면온도를 비교한 결과, heating지반의 온도는 평균 $10.9^{\circ}C$로 $0^{\circ}C$를 유지하였던 무처리 지반에 비해 월등히 높았으나, 수분함량은 평균 1.9% 낮아진 것은 $10.9^{\circ}C$로 유지된 지온으로 인해 수분증발이 계속 이루지는 것으로 사료되었다. 적설량이 15cm 이상 쌓인 상황에서, 히팅 시스템이 설치된 잔디밭에서는 4일만 눈이 완전히 녹았으나 대조구에서는 적설량의 변화가 거의 없었다. Heating system의 보일러 수온을 $55^{\circ}C$에서 $60^{\circ}C$로 높이자, 잔디는 건조 스트레스를 받아 잎끝이 마르는 증상이 나타났다. 앞으로 옥상정원에서의 잔디 재배과 관계된 세부적인 생리적 스트레스에 관한 연구가 필요하다고 판단된다.

• 마이크로전자및패키징학회지
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• 제11권4호
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• pp.37-41
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• 2004

이동 통신 기기의 광대역화에 따라 기존의 인쇄 회로 기판에 비해 양호한 전기적 특성과 수동형 부품을 내장할 수 있는 LTCC(Low Temperature Co-fired Ceramic)에 대한 많은 연구 개발이 진행되고 있으나 불 균일한 수축으로 인해 적용에 한계를 보여 왔다. 본 연구에서는 짧은 시간내에 온도를 균일하게 올릴 수 있는 혼합 가열 방식을 개발하여 하부에서부터 시편의 얇은 층이 순차적으로 소결 되도록 하는 일 방향 소결의 조건을 제공하여 시편 상부 표면의 배선 형상이 종래의 전기로 가열보다 안정적으로 형성되는 결과를 얻었다. 기판의 소결 특성, 배선의 전기적 특성, 그리고 배선의 기계적 특성 등을 비교한 결과, 기판의 소형화와 배선의 고밀도화에 전기로 가열 보다 혼합 가열이 적용 가능성이 높음을 알 수 있었다.