• Journal of Energy Engineering
• /
• v.21 no.2
• /
• pp.144-151
• /
• 2012

A district heating system produces thermal energy and supplies it to a large region. District heating systems can provide higher efficiencies and better pollution control than localized boilers. The heat generated by a district heating system is distributed to the customer via a network of insulated pipes. For the optimal operation of a district heating system, it is important to predict the distributions of pressure, flow rate and temperature of heating fluid within the network of pipes at various operating conditions. In this work, a mathematical modeling was performed to predict the dynamic hydraulic-thermal behaviors of heating fluid in the network of pipes for a district heating system. The mathematical model accounts for the conservations of mass, momentum and energy. In order to verify the validity of modeling, the modeling results were compared with the monitoring data of Gang-nam Branch of District Heating.

• Proceeding of Spring/Autumn Annual Conference of KHA
• /
• 1994.05a
• /
• pp.45-50
• /
• 1994

The energy consumption in apartment houses is investigated according to the heating systems, that is, district, central, and individual heating systems. And, operating conditions of intermittent heating are surveryed and analysed in the central heating systems. As a result, each annual energy consumption of district, central and individual heating system is 143.56 Mcal/m2year, 216.78 Mcal/m2year and 150.68 Mcal/m2year, Also, the heating is generlly started at 04:00 and 17:00 of each day, and the heating system is operated for 2~3 hours per each time.

• Proceedings of the SAREK Conference
• /
• 2009.06a
• /
• pp.1037-1042
• /
• 2009

In connection with a recent research project dealing with heating system in apartment buildings by district heating, it was realised that in general very little information on the actual performance of heating and hot water systems in apartment buildings has been documented. In order to improve of district heating systems, a prediction of the heat demand first needs to be determined before a production plan. this is hot water heat system developed in this paper. this is also analyzed relation heat load with preheat load in hot water heating exchanger system.

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

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

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.493-498
• /
• 2008

Particles or deposit formed by corrosion of the pipe material bring about bad influences on the heating systems with inconvenience, energy loss and so on. In order to obtain the non-corrosive environments, the circulation hot water should properly be treated in several ways to satisfy one or more conditions of the followings: suitable pH-level, low hardness, low oxygen content, low conductivity, low level of chlorides and sulphur compounds and low level of solid particles. This experimental study was carried out to develope the new guidelines on the optimal water quality and directions for water quality management in heating systems. As results, it was recommended that the heating water be maintained pH-level not less than 8, hardness contents as $CaCO_3$ no more than 50 mg/L, turbidity no more than 10 NTU and T-Fe contents 1 mg/L below.

• Proceedings of the SAREK Conference
• /
• 2006.06a
• /
• pp.245-251
• /
• 2006

The main idea of this study is to turn attention on the question of good cooling ability of customer substations in large district heating networks. The main reason for that is based on our experience that the optimization of district heating very often is directed toward production, whereas questions of optimal distribution are neglected if only the necessary load can be supplied and the customer's request for comfort is met. Our view is that low return temperature(operational temperature differences, ${\Delta}T$) in district heating systems is an Important feature for efficient net operation and gives both economic and operational benefits to the district heating supplier Furthermore, it is as well a prerequisite for meeting the customers demand for reliable supply of the heat load. However, in many practical cases we have seen that district heating return temperatures are higher than necessary. Hence, the aim of the study is to propose and verify a method for detection of the most critical consumers of the net and to identify the reasons for resulting high return temperature. From the results, temperature control system is presented as one of the most important reason of high return temperature in DH networks.

• 한국태양에너지학회:학술대회논문집
• /
• 2008.04a
• /
• pp.190-195
• /
• 2008

This study aims to develop the thermal performance and economic analysis program of solar heating system applied to district heating systems. The program, named SOLAN-DHS, is 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 and can design 5 different types of solar systems. 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.

• Journal of the Korean Solar Energy Society
• /
• v.28 no.6
• /
• pp.64-69
• /
• 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
• /
• 2007.11a
• /
• pp.480-487
• /
• 2007

The experimental implementation for different heating systems, district heating and separate heating and power, is discussed in the analysis of the characteristics of energy-usage in apartment complex. Total 20 families are chosen for the experiment, 10 for the district heating and the others for separate heating and power. Among the 10 families, the operating temperature was forced to be controled within certain range of temperatures for 5 ones, and it was left as usual for the other ones. The configuration and general features of each facilities and data acquisition systems are mentioned in brief and the technical specifications for it are also described. The analysis for the experiment results of this investigation is going to be carried out and published in a subsequent paper.