• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.3
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• pp.230-239
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• 2012

Ground-coupled heat pump (GCHP) systems utilize the immense renewable storage capacity of the ground as a heat source or sink to provide space heating, cooling, and domestic hot water. The main objective of the present study is to investigate the cooling and heating performance of a small scale GCHP system with horizontal ground heat exchanger (HGHE). In order to evaluate the performance, a water-to-air ground-source heat pump unit connected to a test room with a net floor area of 18.4 m2 and a volume of 64.4 m3 in the Korea Institute of Construction Technology ($37^{\circ}39'N$, $126^{\circ}48'E$) was designed and constructed. This GCHP system mainly consisted of slinky-type HGHE with a total length of 400 m, indoor heat pump, and measuring devices. The peak cooling and heating loads of the test room were 5.07 kW and 4.12 kW, respectively. The experimental results were obtained from March 15, 2011 to August 31, 2011 and the performance coefficients of the system were determined from the measured data. The overall seasonal performance factor (SPF) for cooling was 3.31 while the system delivered heating at a daily average performance coefficients of 2.82.

• Journal of the Korean Solar Energy Society
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• v.26 no.1
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• pp.1-6
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• 2006

This paper presents the heating and cooling load estimations for the library of a cultural center building located in Gwangju Korea by TRNSYS with Type 56 of multi-zone building components. In this study, energy rate control mode is selected and the design temperatures for heating and cooling are specified respectively as 20oC and 26oC. Reading rooms of the library are located on the third floor of the cultural center building, and this third floor space is modeled as the five thermal zones for the TRNSYS simulation. Among the five zones, attention is given to the two zones which are the reading rooms 1 and 2. Since these two zones are to be heated and cooled by the solar thermal system which is planned to be installed in the building, dynamic thermal behaviors of the two zones are analyzed by the heating and cooling load estimations.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2117-2122
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• 2004

The main objective of the present study is to investigate the performance characteristics of a ground source heat pump (GSHP) system with a 130 m vertical 60.5 mm nominal diameter U-bend ground heat exchanger. In order to evaluate the performance analysis, the GSHP system connected to a test room with 90 $m^2$ floor area in the Korea Institute of Construction Technology ($37^{\circ}39'$ N, $126^{\circ}48'$ E) was designed and constructed. This GSHP system mainly consisted of ground heat exchanger, indoor heat pump and measuring devices. The cooling and heating loads of the test room were 5.5 and 7.2 kW at design conditions, respectively. The experimental results were obtained from July to January in cooling and heating season of $2003{\sim}2004$. The cooling and heating performance coefficients of the system were determined from the experimental results. The average cooling and heating COPs for the system were obtained to be 4.82 and 3.02, respectively. The temperature variations in ground and the ground heat exchanger surface at different depths were also measured.

• Journal of Bio-Environment Control
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• v.32 no.3
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• pp.181-189
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• 2023

Hydrogen has gained attention as an environmentally friendly energy source among various renewable options, however, its application in agriculture remains limited. This study aims to apply the hydrogen fuel cell triple heat-combining system, originally not designed for greenhouses, to greenhouses in order to save energy and reduce greenhouse gas emissions. This system can produce heating, cooling, and electricity from hydrogen while recovering waste heat. To implement a hydrogen fuel cell triple heat-combining system in a greenhouse, it is crucial to evaluate the greenhouse's heating and cooling load. Accurate analysis of these loads requires considering factors such as greenhouse configuration, existing heating and cooling systems, and specific crop types being cultivated. Consequently, this study aimed to estimate the cooling and heating load using building energy simulation (BES). This study collected and analyzed meteorological data from 2012 to 2021 for semi-enclosed greenhouses cultivating tomatoes in Jeonju City. The covering material and framework were modeled based on the greenhouse design, and crop energy and soil energy were taken into account. To verify the effectiveness of the building energy simulation, we conducted analyses with and without crops, as well as static and dynamic energy analyses. Furthermore, we calculated the average maximum heating capacity of 449,578 kJ·h^-1 and the average cooling capacity of 431,187 kJ·h^-1 from the monthly maximum cooling and heating load analyses.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2545-2552
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• 2014

This study is aiming to suggest the effective thermal management system design technologies for the high voltage and capacity battery system of the electricity driven vehicles and introduce the theoretical designing methods. In order to investigate the effective operation of the battery system for the electricity driven vehicles, the heat generation model for Li-ion battery system using the chemical reaction while charging and discharging was suggested and the thermal loads of the heat sources (air or liquid) for cooling and heating were calculated using energy balance. Especially, the design methods for the cooling and heating of the battery system for maintaining the optimum operation temperature were investigated under heating, cooling and generated heat (during charging and discharging) conditions. The battery thermal management system for the effective battery operation of the electricity driven vehicles was suggested reasonably depending on the variation of the season and operation conditions. In addition, at the same conditions under summer season, the cooling method using the liquid and active cooling technique showed a relatively high capacity, while cooling method using the passive cooling technique showed a relatively low capacity.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.286-291
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• 2001

This paper describes an optimal scheduling for ice slurry systems for energy cost saving. The optimization technique applied in the study is the dynamic programming method, for which the state variable is the storage in the ice storage tank and the control variable is the state of chiller's on-off switching. Though the costs during charge period is included in optimization by taking the average cost of ice per hour for slurry making, the time horizon for the simulation is limited building cooling period because accurate charge rate from the ice maker into the ice storage tank cannot be estimated during the charge period. In the operating simulation after optimizing procedure, energy consumption and operating cost for the optimal control are calculated and compared with them for a conventional control with one case of cooling load profile.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.5
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• pp.377-384
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• 2002

For economic evaluation of cooling plant equipments, it is necessary to simplify energy Prediction method, which should includes efficiency corrected by part-load ratio. This study proposed simplified method with regression equations of time-average partial loads and refrigerator capacity. DOE-2 Program was used to carry out a parametric study of twelve design variables. Five input variables were considered to be significant and were used in the regression equations. To test accuracy of simplified method, calculated results were compared with DOE-2 simulated results. Test result showes a good agreement with the simulation result with an error of 5.9∼7.6%. It is expected that this method can be used as an easy prediction tool for comparing energy use of different cooling plants during the early design stage.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.4
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• pp.221-229
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• 2008

This study analyze indoor thermal comfort properties such as PMV, PPD and fluid variables when the cooling loads are light, occupant and ventilation. There are 6 cases to study for the indoor unit installation conditions and ventilation rates. Numerical method is used to study the indoor environmental properties and experimental study is adapted to analyze reaching time by variable cooling load conditions.

• Proceedings of the SAREK Conference
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• 2004.11a
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• pp.49-49
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• 2004

• Structural Engineering and Mechanics
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• v.51 no.6
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• pp.1005-1016
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• 2014

Roles of reactor internals are to support nuclear fuel, provide insertion and withdrawal channels of nuclear fuel control rods, and carry out core cooling. In case of functional loss of the reactor internals, it may lead to severe accidents caused by damage of nuclear fuel assembly and deterioration of reactor vessel due to attack of fallen out parts. The present study is to examine fluid flows in reactor internals subjected to hydrodynamic loads. In this context, an integrated model was developed and applied to two kinds of numerical analyses; one is to analyze periodic loading effect caused by pump pulsation and the other is to analyze random loading effect employing different turbulent models. Acoustic pressure distributions and flow velocity as well as pressure and temperature fields were calculated and compared to establish appropriate analysis techniques.