• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.433-437
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• 2005

This study was carried out the design and analysis of solar thermal system with preheating of returning district heating water for the Chung-ju district heating and cooling system. Two different types of solar collectors are used for this system. TRNSYS simulation program was used for the analysis. As a results, the solar system efficiency is $35.8\%$ for the plate type and $45.1\%$ for the evacuated type solar collector in the case of $50^{\circ}C$ for the returning district heating water temperature. The returning district heating water temperature is on of the very important factors that is influence on the system efficiency. So the effect of the returning district heating water temperature on the system efficiency is analyzed in this study.

• Proceedings of the SAREK Conference
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• 2007.11a
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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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.4
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• pp.297-302
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• 2011

According to the standards for district heating substation established by Korea District Heating Corporation, water heating supply systems at over 150 Mcal/h capacity must employ the 2-stage heat exchanger that improves the system efficiency by reusing the heat included in the return water of district heating system already used for space heating. In this paper, the operating characteristics of the system in accordance with the load distribution of two heat exchangers for pre-heating and re-heating cold city water are investigated. The results including mass flow rate, return temperature etc. help to manage district heating system economically.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.10
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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.

• Journal of Korean Society for Atmospheric Environment
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• v.6 no.1
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• pp.51-56
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• 1990

This Study shows the effect of the district heating on the $SO_2$ concentration reduction. In order to analyze the effect of the district heating, three alternatives were set up as follows; Alternative I represented present central heating system, and Alternative II and Alternative III represented district heating system of which the scale were different from. The concludions of this study are as follows; In case of the Alternative II and III, annual average $SO_2$ concentration are reduced by 9.0% and 14.6% respectively, and winter season $SO_2$ concentrations are reduced by 12.2% and 15.8% respectively, at the highest points. The average reduction rates of $SO_2$ concentration in the district heating area are about the same as the reduction rates at the highest points. Also, it was found that using the district heating system, the ground level $SO_2$ concentrations could be reduced within the area of 5 to 10 km radius.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.698-701
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• 2017

The district heating system supports currently 1.3 million of houses in South Korea, and it is composed of two main parts: provision and distribution. For the provision part, Korea District Heating Corporation supervises the system with proper devices and experts, whereas for the distribution parts, there is no main supervision system and it depends highly on experts although it is very difficult to find the proper experts. In this paper, we consider IoT based remote management system for district heating distribution to properly supervise heating distribution by experts and/or programs remotely.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.6
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• pp.283-292
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• 2015

A model of apartment heating load in a district heating system could be useful in the management and utilization of energy resources, since it could predict energy usage and so could assist in the efficient use of energy resources. The heating load in a district heating system varies in a highly nonlinear manner and is subject to many different factors, such as heating area, number of people living in that complex, and ambient temperature. Thus there are few published papers with accurate models of heating load, especially in domestic literature. This work is concerned with the modeling of apartment heating load in a district heating system in winter, using the reduced least square support vector machine (LS-SVM), and with the purpose of using the model to predict heating energy usage in domestic city area. We collected 23,856 pieces of data on heating energy usage over a 12-week period in winter, from 12 heat exchangers in five apartments. Half of the collected data were used to construct the heating load model, and the other half were used to test the model's accuracy. The model was able to predict the heating energy usage pattern rather accurately. It could also estimate the usage of heating energy within of mean absolute percentage error. This implies that the model prediction accuracy needs to be improved further, but it still could be considered as an acceptable model if we consider the nonlinearity and uncertainty of apartment heating energy usage in a district heating system.

• Environmental and Resource Economics Review
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• v.10 no.3
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• pp.367-386
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• 2001

In this paper we analyze the environmental advantages of district heating system. We construct three econometric models to analyze the energy consumption and economic cost as well as the emission of the major pollutants like $SO_x$, $NO_x$, DUST, and $CO_2$. As the size of heating supply is larger, the district heating system is evaluated to be better than other heating systems environmentally and costly in the long run. Especially, the district heating reduces $SO_x$ emission significantly when the size of heat production is large. But the advantages of district heating system are very sensitive to the fuel mix and heat source.

• Journal of the Korean Solar Energy Society
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• v.28 no.6
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• pp.64-69
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• 2008

In this study the thermal performance and economic analysis program of solar heating system for district heating was developed. This program, named SOLAN-DHS and based on TRNSYS, consisted of four modules like as user's interface for system input/output, library, and utilities and a calculating engine. SOLAN-DHS simplifies user's input data through the database of most system engineering data including weather data of 17 areas in Korea. Five different types of solar systems which can be applicable to district heating system were presented in this program. Due to the user-friendly layout, all design parameters can be changed quickly and easily for the influence on system efficiency. The reliability of SOLAN-DHS was finally verified by the experiments.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.663-668
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• 2008

This study was carried out solar heating system design for district heating and it's the performance analysis by experiment. This experimental system was installed in Bundang district heating area in the end of 2006. The flat plate and vacuum tube solar collector are combined in one system. So district heating water is heated first by flat plate solar collector and than by vacuum tube solar collector. This solar heating system has not a solar buffer tank and is operating with variable flow rate to obtain a setting temperature of $90{\sim}95^{\circ}C$. As a result, the daily solar thermal collection efficiency is about 30 to 40% for the plate type and 50 to 55% for the vacuum tube solar collector. It varied especially depend on the weather condition like as solar radiation and ambient temperature. This variable flow rate system can be also reduced much pumping power more than 50%.