• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.3 no.1
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• pp.23-29
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• 2007

For the perfomance test of geothermal system, a large pilot of capacity of 50RT is built and operated in office building. This system is planed hybrid system with cooling tower as asisstance heat sink. From October, 2004 to September, 2005, this system is operated andmonitored. As the result, COP of heating periods is about 3.46 and COP of cooling periods is about 4.1. Therefore, geothermal system is useful and suitable in Korea.

• Journal of Institute of Convergence Technology
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• v.3 no.1
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• pp.19-23
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• 2013

This study is concerned with air-conditioning system in use of thermoelectric device. It is introduced that the well designed structures for better cooling & heating performance with high efficiency. And also it is performed that the system performance test of four types trial products for the use of hybrid commercial vehicle. System performance is affected by many component parts, especially heat sink design & power control method. It is applied that dual extrusive fin tube with buffer zone for the effective radiating of circulating liquid in tube. And also it is applied that power supply method with constant-current system. It is attained that system cooling capacity is 1.2kW, COP is 0.95.

• KIEAE Journal
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• v.5 no.3
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• pp.25-31
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• 2005

Computer simulations were performed for Heating Ventilating and Air-Conditioning (HVAC) systems to figure out more efficient maintenance methods for the building used for adolescent trainees. This study aims at suggesting design alternatives for optimum operation and performing life cycle cost (LCC) for each alternative. First, the capacity of the heat source equipment was determined using annual maximum heating and cooling loads. Annual loads were calculated and applied to the alternative for the purpose of calculating annual energy cost. Second, several types of data were collected to predict energy cost. Finally, the pay back period for each alternative was calculated using total cost estimation during standard duration period. This study indicates that the absorption chiller that does not occupy most part of a mechanical room, and does not need much operation cost was most economical.

• Korean Journal of Agricultural Science
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• v.19 no.1
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• pp.91-96
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• 1992

Diesel engine being used on power tiller has over heating problem while running at the rated power range, The reason for overheating the engine is mainly owing to so small capacity of cooling system. This study was conducted to determine relatively optimum capacity of cooling system for the diesel engine. The results obtained are summarized as follows. 1. The capacity of cooling system for the diesel engine being used in the rural area was not sufficient to cool the engine at the rated power. 2. It is desirable that the cooling water flow rate was $12{\ell}/min$ if we used supplementary pump for increasing the cooling efficiency. 3. As cooling water was circuited $12{\ell}/min$, highest temperature of cooling water was $91^{\circ}C$. This value is within $88^{\circ}C{\pm}5^{\circ}C$ of SAE Standard criterion.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.2
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• pp.9-15
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• 2017

When applying geothermal systems in cities such as seoul where high density development prevails, the selection of geothermal system capable of obtaining a large capacity in the limited grounds is necessary. In this study, an easy-to-use design tool is developed in the form of spreadsheet by applying the calculation theory of existing closed-loop vertical ground heat exchanger that can be used in the early design stage of the open-loop ground heat exchanger. By only using the maximum cooling and heating load, it is possible to calculate optimal design open-loop ground heat exchanger. Further research is needed, we are plan to improve the program considering the heat loss of groundwater flowing in the inner casing, G-Function for Open-Loop, and verification by applying actual projects.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.1091-1095
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• 2005

This study is performed to develop a tripple-tube exchanger which can improve the system efficiency. Three different tube diameters are compacted by one body(tripple-tube) to recover waste heat from heat exchanging among the fluids. With this, the tripple-tube shows higher cooling capacity than the double-tube after comparing between those two systems. The results of this study are basic data to design the optimum tripple-tube heat exchanger.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.13 no.2
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• pp.1-8
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• 2017

Outdoor design temperature is important for selecting proper capacity of heating and cooling systems of a building to implement indoor thermal comfort and save energy consumption. The purpose of this study is to investigate the change of South Korea outdoor design temperature according to the assigned period. When outdoor design temperature of 8 locations calculated with the latest weather data during 2008~2015 years using ASHRAE Bin method are compared to the standard temperature of Ministry of Land, Infrastructure and Transport which is widely used for designing South Korea air-conditioning system at present, the maximum temperature difference becomes $0.97^{\circ}C$ for cooling, and $1.94^{\circ}C$ for heating. Due to wide outdoor temperature variation, update of outdoor design temperature based on recent weather data is recommended.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.6
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• pp.392-399
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• 2011

Ground-coupled heat pump(GCHP) systems have been shown to be an environmentally-friendly, efficient alternative to traditional cooling and heating systems in both residential and commercial applications. Although some work related to performance evaluation of GCHP systems for commercial buildings has been done, relatively little has been reported on the residential applications. The aim of this study is to evaluate the cooling and heating performances of a vertical GCHP system applied to an artificial detached house($117\;m^2$) in Seoul. For this purpose, a typical design procedure was involved with a combination of design parameters such as building loads, heat pump capacity, borehole diameter, and ground thermal properties, etc. The cooling and heating performance simulation of the system was conducted with different prediction times of 8760 hours and 240 months. The performance characteristics including seasonal system COP, average annual power consumption, and temperature variations related to ground heat exchanger were calculated and compared.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.8
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• pp.468-474
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• 2009

Ground water source heat pump system is the oldest one of the ground source heat pump systems. Despite of this, little formal design information has been available until recently. The important design parameters for open system are the identification of optimum ground water flow, heat exchanger selection and well pump. In this study, the capacity of 50 RT system of two well type ground water heat pump system was used. As a result, static water level was -7 m and the level during the heating operation was -32 m, cooling operation was -40 m. The initial static water level recovered within 48 hrs. The temperature of ground water is $15.6^{\circ}C$ for heating season and $16.2^{\circ}C$ for cooling season and does not depend on the outdoor temperature. Operation efficiency of the system shows that, COP 3.1 for heating and COP 4.2 for cooling.

• 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.