• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.14 no.1
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• pp.1-7
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• 2018

A ground source heat pump system should be equipped with devices to measure the generated heating or cooling heat amount in Korea. Generally, the heat measuring devices have been developed to estimate consumed heat amount in residential or commercial buildings from a central air-conditioning system or a district heating system. In this study, two representive heat measuring devices used for buildings were selected, and the accuracy of them were experimentally estimated at the ground source heat pump operating conditions. The obtained heat amounts from the heat measuring devices were deviated within 4.3% comparing with the precise values calculated from an accredited test facility. Even though the accumulated heat amount values of the heat measuring devices had a small difference comparing with the precise values, the temperatures of heat measuring devices showed greatly different values comparing with the precise temperature. Therefore, it is highly recommended to develop the heat measuring devices which is appropriate for the ground source heat pump systems.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.5
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• pp.459-466
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• 2004

In order to save the energy in apartment houses, it is essential that the energy amount consumed in heating per household should be surveyed and analyzed according to heating method, which can be classified into unit, central and district methods. As a basis, we selected the household with nominal area of 32 py. because it accounts for the most percentage in Korea. It is estimated that the gas amount for cooking is 90 ㎥ and the energy amount for hot water supply is 11.41 GJ for a year, which is necessary to calculate the heating energy. Through the survey of actual energy consumption in Seoul and Gyeonggi, the energy amount used in heating can be obtained according to the heating type: 26.02 GJ/year for the unit heating, 28.09 GJ/year for the central heating and 40.61 GJ/year for the district heating.

• Proceedings of the SAREK Conference
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• 2004.11a
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• pp.28-28
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• 2004

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.205-208
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• 2020

This paper examines the approach, enabled by using SiC power devices, to unify the inverter design for central air conditioning (CAC) system for both single- and 3-phase input, and reduce the PFC inductor size to be PCB-mountable. By using SiC-instead of Si-diode in PFC stage, it is possible to increase the switching frequency from 16kHz to 60kHz to reduce the required PFC inductance from 0.93mH to 0.25mH, thus enable PCB-mounting of inductor. With the next step of using 1200V SiC MOSFET instead of Si-IGBT, the DC link voltage can be boosted from 311Vdc to 550Vdc in PFC stage, allowing the inverter and compressor used in 3-phase input CAC be used for single-phase input as well. Furthermore, using SiC MOSFET in inverter stage can further reduce total loss system total loss to 200.8 W. Simulation and experimental results are presented in the paper.

• Proceedings of the SAREK Conference
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• 2004.06a
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• pp.143-143
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• 2004

• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.139-139
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• 2007

• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.7
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• pp.392-397
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• 2013

To fulfill the demands concerning energy efficiency for zero energy buildings, various technologies of architects and engineers are required. This study aims to estimate the thermal performance of heat source equipment in which part load characteristics are considered in an office building. Overestimation of heat source equipment was reviewed through literature survey, and heating and cooling loads depending on the capacity and division of the equipment were analyzed through a simulation program (DOE-2.1E). The conclusions gained from this study are as follows; 1) The more the division of equipment, the less the heating and cooling energy consumption. 2) When a large item of equipment is divided into two small items of equipment, the optimum application rate showed as 5:5 for chiller, and 7:3 for boiler, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.68-73
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• 2011

In this study, a group of home bus system(HBS) is used to manage difference types of household appliances or many household appliance of the same type. The existing central controller is analyzed, and an independent control system is built to devise new methods to design the PC HBS. The newly designed system is installed in an air-conditioned building; the system can be monitored and controlled from a control room or from an office. By using the system, we can efficiently manage future energy needs and control large-scale integrated electronics and home automation system to an individual manage to build large is expected to contribute.

• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.138-138
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• 2007