• 한국지열·수열에너지학회논문집
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• 제18권4호
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• pp.33-44
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• 2022

In this study, we analyze the existing heating and cooling operation method for an office-type complex building with a central heating and cooling system, and examine the effects of applying various EMS that can be applied according to the load size to save energy in the building. For this purpose, simulation analysis was performed. As a control method, reset control of chilled water, hot water, cooling water and supply air temperatures, optimal start/stop of heat source, and number of heat source control were applied according to the load size, and energy consumption was analyzed accordingly. In addition, when all of these control methods were applied, the overlapping energy saving effect was finally confirmed. As a result, it was possible to confirm the energy saving effect when EMS for reset control and heat source control were applied compared to the existing control method of the heating and cooling system, and the effect for the case of using all these control methods in combination was also confirmed.

• 한국전자통신학회논문지
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• 제7권3호
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• pp.607-615
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• 2012

본 연구는 대전광역시의 아파트단지 중 150세대이상 128개 아파트단지를 대상으로 2011년 3/4분기에 부과된 관리비 자료를 수집하여 연구하였다. 아파트 관리비는 난방방식에 따라 차이가 발생할 것이다는 가설을 가지고 연구에 접근하였다. 연구 결과를 도출하기 위하여 SPSS를 이용하여 다중회귀분석으로 실시하였다. 그 결과 첫째로 아파트 특성에 따른 관리비에 미치는 영향을 분석한 결과 공통적으로 관리면적, 입주년도, 난방방식이 관리비에 영향을 미치고 있었으며, 둘째로 난방방식에 따른 일반관리비, 경비비, 수선유지비의 경우는 개별난방방식이 유리하고, 청소비는 난방방식과 차이를 보이지 않고 있는 것으로 나타났다.

• KIEAE Journal
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• 제10권1호
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• pp.57-64
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• 2010

Electric energy is indispensible of the development of the industrial and living sector. Among the energy sectors, the building area shares 20% of the produced electric power in Korea. As we plan to supply the apartment, we need to forecast the required amount of the electric energy and supply the infrastructure to apartment for the lighting, cooling. Nonetheless, it is not easy to forecast the required amount of the electric energy, considering the management aspect, building physical aspect and social-geographic aspect. In this paper, it studied the estimation model of the electric energy, reflecting the affecting variables such as total area, number of household, geography and so on. The estimation model is proposed in 3-types which explained in central heating, individual heating and district heating, and each type have two estimation model, reflecting the affecting variable and corelation between variables to eliminate the muticolinearity. The unit of electric energy consumption per area and year is similar in three heating type and the results are as follows; the central heating is $34.446kWh/yr{\cdot}m^2$, individual type is $35.756446kWh/yr{\cdot}m^2$ and district heating is $34.285446kWh/yr{\cdot}m^2$.

• 한국지열·수열에너지학회논문집
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• 제12권4호
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• pp.8-14
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• 2016

In this study, the effects of prediction and reset control of outdoor air temperature on energy consumption for central heating system are researched by using TRNSYS program package, and the control performances with the suggested methods of prediction and reset control of outdoor air temperature are compared with the existing ones. As a result, the value of coefficient of determination $R^2$ for the predicted outdoor temperatures is improved and the suggested control method shows maximum 21.8% energy saving in comparison with existing control ones.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.60-65
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• 2008

The near-optimal control algorithm for central cooling and heating system has been developed for minimizing energy consumption while maintaining the comfort of indoor thermal environment in terms of the environmental variables such as time varying indoor load and outdoor temperatures. The optimal set-points of control parameters with near-optimal control are supply air and chilled or hot water temperatures. The near optimal control algorithm has been implemented by using LabVIEW program in order to analyze energy performance for central cooling and heating control system.

• 대한건축학회논문집:구조계
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• 제36권2호
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• pp.175-180
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• 2020

The purpose of this study was to clarify precautions during the design and operation phases for energy reduction in a public office building. To check the operation status of the building, we measured the indoor temperature and humidity in the office space of the building installed central heating and cooling systems. And we analyzed these data and annual BEMS data. As a result, we found six problems related to decreasing system efficiency. Based on these, we presented the information to improve the efficiency of the system from the design and operation phase. Also, we present the need for a system to support the decision-making of operational managers in real-time for the energy efficiency of the building.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.56-61
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• 2009

Paradigm depending only on fossil fuel for building heat source is rapidly changing. Accelerating the change, as it has been known, is obligation for reducing green house gas coming from use of fossil fuel, i.e. reaction to United Nations Framework Convention on Climate Change. In addition, factors such as high oil price, unstable supply, weapon of petroleum and oil peak, by replacing fossil fuel, contributes to advance of environmental friendly renewable energy which can be continuously reusable. Therefore, current new energy policies, beyond enhancing effectiveness of heat using equipments, are to make best efforts for national competitiveness. Our country supports 11 areas for new renewable energy including sun light, solar heat and wind power. Among those areas, ocean thermal energy specifies tidal power generation using tide of sea, wave and temperature differences, wave power generation and thermal power generation. But heat use of heat source from sea water itself has been excluded as non-utilized energy. In the future, sea water heat source which has not been used so far will be required to be specified as new renewable energy. This research is to survey local heating system in Europe using sea water, central solar heating plants, seasonal thermal energy store and to analyze large scale central solar heating plants in German. Seasonal thermal energy store necessarily need to be equipped with large scale thermal energy store. Currently operating central solar heating system is a effective method which significantly enhances sharing rate of solar heat in a way that stores excessive heat generating in summer and then replenish insufficient heat for winter. Construction cost for this system is primarily dependent on large scale seasonal heat store and this high priced heat store merely plays its role once per year. Since our country is faced with 3 directional sea, active research and development for using sea water heat as cooling and heating heat source is required for seashore villages and building units. This research suggests how to utilize new energy in a way that stores cooling heat of sea water into seasonal thermal energy store when temperature of sea water is its lowest temperature in February based on West Sea and then uses it as cooling heat source when cooling is necessary. Since this method utilizes seasonal thermal energy store from existing central solar heating plant for heating and cooling purpose respectively twice per year maximizing energy efficiency by achieving 2 seasonal thermal energy store, active research and development is necessarily required for the future.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.459-465
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• 2007

This study was conducted to calculate the LCC of a apartment complex with a type of heating system, district heating and cogeneration system. For the purpose of analyzing LCC according to size of apartment complex, 500, 1,500 and 4,000 houses of model apartment selected. This research performs design of heating system and the life cycle cost analysis including an initial cost, energy cost, maintenance and operation cost, replacement cost and renovation cost during the project period(15years). According to the calculated results, 1) Initial cost of cogeneration system with 500, 1500 and 4000 houses is higher than district heating system each of 20%, 13%, 12%. 2) In case of cogeneration system, the payback period by electric generation is 5.21, 4.92 and 4.47 years and saving cost was calculated 29 billion won, 94 billion won and 262 billion won after payback period. 3) Cogeneration system LCC was 1.12, 1.07 and 1.06 times larger than district system with the size of apartment complex. According to the case of this study district heating system is more efficient than cogeneration system in terms of the reduction of LCC. 4) Gas Engine Co-generation System is more efficient than other systems because it can collect progressive part from electric charge progressive stage system. However, the efficiency is decreasing because of raising of fuel bills(LNG) and lowering of power rate for house use. Especially the engine is foreign-made so the cost of maintenance and repair is high and the technical expert is short. 5) District heating is also affected by fuel bills so we should improve energy efficiency through recovering of waste heat(incineration heat, etc.). Also, we should supply district cooling on the pattern of heat using of let the temperature high in winter and low in summer.

• 천문학회보
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• 제38권2호
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• pp.49.2-49.2
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• 2013

We report preliminary results from a radio study of central galaxies in cool and non-cool core clusters. A cooling flow is expected to rapidly form in the center of galaxy clusters unless additional heating mechanisms such as merging with sub clusters are at work. It has been suggested that cool flows can feed the AGN in the central galaxies, increasing their power. On the other hand, the AGN feedback can also affect the surrounding medium, heating back up the gas in the cluster core region. In this study, we investigate the co-evolution of cool flows and the AGN of galaxies located in the cluster center. For this study, we have selected 13 radio bright central galaxies from clusters with a range of cooling time scale. In this work, we present results of our recent observations using the Korean VLBI Network. We discuss the properties of the sample in radio and other wavelengths.

• 설비공학논문집
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• 제27권10호
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• pp.544-551
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• 2015

This study was conducted to determine the LCC of apartment complexes with district heating and a cogeneration system. For the purpose of analyzing LCC according to the size of the apartment complex, 500, 1,500, and 4,000-unit model apartments were selected. Analysis was performed on the design of the heating system and the life cycle cost including total construction cost, maintenance and operation cost for the duration of the project period (15 years). According to the calculated results, 1) The initial cost of the cogeneration system for 500, 1,500, and 4,000-unit apartments is higher than that of the district heating system by 20%, 13%, and 12%, respectively. 2) In the case of the cogeneration system, the payback period by electric generation was found to be 5.21, 4.92 and 4.47 years, and saving cost was calculated to be 29 billion won, 94 billion won and 262 billion won after the payback period for 500, 1,500, and 4,000-unit apartments, respectively. 3) The LCC values of the cogeneration system were 1.12, 1.07 and 1.06 times larger than those of the district system according to the size of the apartment complex. In this study, the district heating system was found to be more efficient than the cogeneration system in terms of LCC reduction. 4) District heating is affected by fuel bills, so energy efficiency should be improved through recovering waste heat (incineration heat, etc.). Also, district cooling should be provided according to heat use to keep the temperature high in winter and low in summer.