• Journal of Korean Society of Steel Construction
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• v.23 no.5
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• pp.569-579
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• 2011

Heating pipes, which are among the main equipment in district heating systems, can be classified into supply and return pipes. Because when the district heating transmission pipe, which is charged with district heating in small to medium-size cities, is under thermal stress during temperature variances in heating water, it suffers from the fatigue phenomenon caused by the thermal stress, according to the number of its service years. District heatingpipes have shown various characteristics according to the operating condition of the service connections, and the irregular temperature variance has had a bad influence on fatigue heating pipes. Therefore, in this study, a field test on laid heating pipes was performed, and the data for each region were analyzed. Also, the fatigue safety of district heating pipes was evaluated via cycle-based evaluation and stress-based evaluation.

• Journal of the Korean Society for Heat Treatment
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• v.35 no.4
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• pp.193-202
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• 2022

Manholes and underground spaces are installed to manage the buried heat transport pipes of the district heating system, and the corrosion damage of the equipment placed in this space often occurs. The purpose of this work is to identify locations with a high risk of corrosion damage in the air vent and to establish preventive measures based on precise analysis via sampling of heat transport pipes and air vents that have been used for about 30 years. The residual thickness of the air vent decreased significantly by reaching ~1.1 mm in thickness, and locations of 60~70 mm away from a transport pipe were the most vulnerable to corrosion. The energy dispersive X-ray spectroscopy (EDS) analysis was performed in the corroded oxides, and it was found that chloride ion was contained in the corrosion products. Anodic polarization tests were carried out on the air vent materials (SPPS250, SS304) with varying the amounts of chloride ions at two different temperatures (RT, 80℃). The higher concentration of chloride ions and temperature are, the lower corrosion resistances of both alloys are.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.9 s.240
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• pp.1235-1242
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• 2005

A district heating(DH) system supplies environmentally-friend heat and is appropriate for reduction of energy consumption and/or air pollutions. The DH transmission pipe, composed of supply and return pipes, has been used to transmit the heat and prevent heat loss during transportation. The two types of pipes are operated at a temperature of $75\~115^{\circ}C\;and\;40\~65^{\circ}C$, respectively, with an operating pressure of less than 1.568MPa. The objectives of this paper are to systematize data processing of transition temperature and investigate its effects on fatigue life of DH pipes. For the sake of this, about 5 millions temperature data were measured during one year at ten locations, and then available fatigue lift estimation schemes were examined and applied to quantify the specific thermal fatigue life of each pipe. As a result, a relational database management system as well as reliable fatigue lift evaluation procedures is established for Korean DH pipes. Also, since the prototypal evaluation results satisfied both cycle-based and stress-based fatigue criteria, those can be used as useful information in the future fer optimal design, operation and energy saving via setting of efficient condition and stabilization of water temperature.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.143-150
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• 2006

Recently, in proportion to increased demand on environmentally-friendly heat source, efficient management of district heating(DH) system becomes one of important issue. The objectives of this paper are to systematize data processing of transition temperature, investigate the effect of temperature variations on thermal fatigue and find out a way to improve design fractures of Korean DH pipes. For this purpose, reliable fatigue lift evaluation procedures are examined and applied to quantify thermal fatigue lives. Also, as a prototypal optimization analysis results, mean value of original cross sectional area of selected pipes was reduced 18.6% sustaining their sufficient margins against fatigue failure. So, it is anticipated that the output of this research can be used as useful information of optimal design and operation in the future.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.637-642
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• 2008

The concept of district heating involves centralised heat production where heat is distributed to consumer via a piping network. The objective of this work is to identify the Flexible Pipe from an economy, execution, maintenance point of view. Flexible Pipe has in some countries, especially in Europe, been used for many years in district heating. In spite of years of experience, there still exist doubts about the possibilities of using flexible pipes in district heating applications, mostly because of no experiences in domestic market. The advantage of flexible pipe systems is their flexibility. This holds not only for the inner pipe but also for the total pipe system including insulation and jacket. Even for the largest diameter the minimum radius of curvature is given to 1.5m. The most important difference between flexible pipe systems and preinsulated steel pipes is their simple and quick assembly. Such information could provide a basis for making reasonable hypotheses about consumer preferences, to foam a basis for making future marketing more effective.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.581-584
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• 2005

A district heating(DH) system supplies environmentally-friend heat and is appropriate for reduction of energy consumption and/or air pollutions. The objectives of this paper are to systematize data processing of transition temperature, investigate its effects on fatigue life of DH pipes and optimization for size of DH pipes. A relational database management system as well as reliable fatigue life evaluation procedures is established for Korean DH pipes. Also, since the prototypal evaluation results satisfied both cycle-based and stress-based fatigue criteria. Through the optimum design process, the cross section diminished 18.64% and the CUF diminished 23.35%. So, it can be used as useful information in the future for optimal design, operation and energy saving via setting of efficient condition and stabilization of water temperature.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.8 no.3
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• pp.19-28
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• 2012

In a heat only boiler system of a steam power plant, outdoor air required for combustion is made to pass through indoor space for increasing the boiler efficiency. Due to heat generated by various equipments, temperature of the air that enters the boiler will increase resulting in combustion efficiency. If the outdoor air temperature is low, however, this will cause freezing and bursting of pipes which are filled with water. It is especially fatal to small diameter pipes and pipes connected to measuring instruments. The purpose of this study is find operation and outdoor conditions where this phenomena can happen and also establish preventive measures to avoid this problem.

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

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.26 no.5
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• pp.218-223
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• 2014

Korea District heating corp. recently give an attention to combine the district heating and supply pipes as a two pipe system that are in the present system separated with room heating and warm water supply pipe, and the two pipe system is commonly applied for heating service in European countries. In the new two pipe system, only one heat source is supplied to a house and partitioned into room heating and warm water supply by household substation. So the effective distribution of supplied heat source in accordance to user intention is very important. This paper presents the development and performance test of three-way proportional control valve for a combined heat source system in district heating. The proposed valve is controlled to partition heat source into two different directions : hot water distributor for space heating and household substation for warm water supply in response to the pressure drops of tap water caused by the user. The performance investigation is shown within 3% of error compared to the theoretical model of the three-way proportional valve and its controllability is verified.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.127-128
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• 2010

As P-new-city is planned and constructed, district eating utilizing an existing near-by power plant's waste heat is considered as an economic and environment friendly way of providing heating to the new city. Many pipeline diameters and pumping station location and capacity were assumed, investigated and optimized, to satisfy the customers' heat demand considering common district heating pipe-network design and construction practice, and also and construction, pumping station land price and construction and the pumping energy cost during lifetime of DH systems.