• Journal of Korean Institute of Industrial Engineers
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• v.4 no.2
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• pp.97-105
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• 1978

A mathematical model is developed in order to describe the network configuration and heating distribution to a Central District Heating System for an Urban Residential Community. The purpose of using this model is to optimize operating costs and to distribute heat to the Residential Community efficiently. In particular, because of the inherent nonlinearity and dual optimization of the problem a dyamic programming approach is taken. It is turned out that the optimal cost of the system is a strong non-linear function of the network. In particular, it is found that increasing N, the number of houses, may not necessarily imply increased costs. It is felt that past failure of producing economical systems may be due to the improper attention given to the network.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.99-104
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• 2011

This paper describes a design strategy at conceptual design stage using RETScreen software tool for building application of renewable energy resources. Currently, government and public buildings are required to adopt renewable energy systems with a minimum requirement for the amount of renewable energy supply. Meanwhile, there is a certificate program for private office buildings to enhance propagation of renewable energy systems. When considering application of renewable energy systems to a building, it is worthwhile developing a method to determine optimal design sizes of renewable energy systems. In the paper, a design strategy is introduced with a couple of case studies to determine optimal capacities of each renewable energy system in a building and suggest to use the method to evaluate the system for the building certificate program and the mandatory renewable target program. Objective functions considered in the study are initial system cost and reduction of CO2 emissions from the system. In the optimization study, it is assumed that solar thermal collectors are installed to satisfy solar fraction of 60%. Other renewable energy systems such as ground-source heat pump, solar PV and non-renewable systems such as electric chiller and gas-fired boiler are sized using an optimal sizing method with RETScreen suggested the authors previously.

• Proceedings of the SAREK Conference
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• 2005.06a
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• pp.121-121
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• 2005

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.3
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• pp.103-109
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• 2016

The purpose of this study is to perform comparative economic evaluation for the systems of ground source heat pump (GSHP) and district heating and cooling (DHC) by focusing on the analysis of operation case of GSHP. The adapted research object is a public office building located in Seoul. The capacity of ground source pump is about 3,900 kW. Ground heat exchanger is closed loop type. The analysis period for life cycle cost is 30 years. Economic evaluation is assessed from the viewpoints of the following four parts: initial cost, energy cost, maintenance and replacement cost, and environment cost. The total life cycle cost of GSHP is approximately 8,447 million won. The cost of the DHC System is approximately 3,793 million won. The cost of the DHC is approximately 46% lower than GSHP system under the condition of current rate for GSHP and DHC.

• Journal of Fisheries and Marine Sciences Education
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• v.17 no.1
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• pp.18-25
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• 2005

We have researched 10,811 schools to evaluate the characteristics of school buildings and the conditions of heating and cooling systems at the elementary, middle and high school levels. Air conditioning systems in school buildings are related to school scale, and 35% of the researched schools have less than 10 air conditioned classrooms among all of the schools in Korea. The LOADSYS is used to grasp the characteristics of school buildings heating and cooling load. From the results of this work, the heating load differs by nearly 24% between Seoul and Busan, but other than that there are not so many serious regional differences. Almost 85.4% of the classrooms are equipped with heating facilities and 6.9% of them are equipped with heating and cooling facilities. As a result, it is necessary to make improvements in 31.8% of the classrooms using only heaters and 14.6% of the classrooms not equipped with HVAC. The survey shows that there is a wide gap in the heating equipment status of the classrooms according to the region and school district.

• Journal of Korean Institute of Industrial Engineers
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• v.23 no.1
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• pp.115-127
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• 1997

A GDHS(Geothermal District Heating System) is a heating system supplying a group of districts with heat extracted from geothermal sources. The advantages of GDHS include saving fuel consumption as well as reducing air pollution. This paper presents a case study for the economic feasibility model and analysis of a GDHS with which central/individual heating systems are replaced. Configuring to a simplified GDHS which consisits of subsurface systems, surface systems, and transmission/distribution systems, we find out the properties of the system and the model parameters affecting the initial investment/operating costs in order to develop a classical economic feasibility model given geothermal temperature. Based on our model parameter space, we analyzed the geothermal development project of the Jejoo Island probabilistically given prior information such as the expected geothermal power, the demand size and the length of transmission/distribution pipes.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.214-220
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• 2011

This paper studies about the assessment of thermal performance between wet ondol system and electric ondol system. Electrical ondol systems shows faster warm-up time, higher floor surface temperature distribution and lower power consumption than wet ondol system. However, if we provide heat regularly wet ondol system which has more heat capacity shows greater thermal storage than electric ondol system. Therefore, we could conclude that wet ondol system which keeps temperature regularly by the thermal storage show better energy-efficiency in case of using the central heating and district heating system. However, Electrical ondol system shows better efficiency in case of using the space during short time or individual heating systems which needs to heat quickly. The Experiment says that electric ondol system has more benefits on timing to reach the set temperature and energy-efficiency than wet ondol system.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.2
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• pp.10-16
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• 2019

In this study, the present regulation of heat metering for the ground source heat pump was investigated. The ground source heat pump has been adopting the heat metering system used in the district heating system for estimating the heating and cooling energy production amount. The accuracy of the present heat metering systems for a water to water ground source heat pump is low, because the system for district heating has a relatively high temperature range comparing with the ground source heat pump operating conditions. Even though the heat amount for the building side should be measured, the heat absorption and extraction amount from or to the ground was measured for the water to air ground source heat pump due to the difficulty of estimating the air side heating and cooling capacity in the present regulation. It is highly recommended to validate the heat metering system to have reliability for the ground source heat pump and develop the system to be applicable water to air ground source heat pump.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.226-230
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• 2008

DSM Investment Programs are accomplished by KOGAS and KDHC, based on 'Article 15, Rational Energy Utilization Act'. By this act, suppliers are accomlishing DSM Investment Programs with much budget and contribute national DSM. However, there was no assessment systems for the quantitative evaluation of DSM Investment Programs in natural gas and district heating domains, yet. In order to overcome this problem, we constructed the assessment system which select quantitative programs, analyze impact factors, develop logic and equations and computerize this system. With this system, we can give objective and reliable output of DSM Investment Programs and evaluation tool to promote them efficiently. In this paper, we write the development process, method and utilization of this assessment system.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2010.04a
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• pp.108-111
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• 2010