• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.505-510
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• 2001

Advanced Pressurized Reactor 1400(APR1400), which is a standard evolutionary advanced light water reactor(ALWR), has been developed from 1992 as one of long-term Government Project(G-7). The APR-1400 is designed to operate at the rated output of 4000MWt to produce an electric power output of around 1450MWe. Due to the increased electric power, In Nuclear Power plant huge quantities of heat are generated in the thermo-dynamic process used for producing electrical energy. So, There is considerationly additional cooling, Heat transfer area and increased cooling water of Heat Exchanger which take care of the different smaller cooling duties within the nuclear power plant. We review applying to PRE instead of Shell-and-Tube Heat exchanger. In this paper, we describe the major design features of PRE, Comparison between a PHE and a Shell-and-Tube Heat Exchanger, and then Applicability of Plate Heat Exchanger in Nuclear Power Plant Component Cooling water systems.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.471-476
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• 2007

Effluent ground water overflow in deep and broad ground space building. Temperature of effluent ground water is in $12{\sim}20^{\circ}C$ annually and the quality of that water is as good as living water. Therefore if the flow rate of effluent ground water is sufficient as source of heat pump, that is good heat source and heat sink of heat pump. Effuent ground water contain the thermal energy of surrounding ground. So this is a new application of ground source heat pump. In this study open type and c lose type heat pump system using effluent ground water was installed and tested for it church building with large and deep ground space. The effluent flow rate of this building is $800{\sim}1000$ ton/day. The heat pump capacity is 5RT each. The heat pump cooling COP is $4.9{\sim}5.2$ for the open type and $4.9{\sim}5.7$ for close type system. The system cooling COP is $3.2{\sim}4.5$ for open type and $3.8{\sim}4.2$for close type system. This performance is up to that of BHE type ground source heat pump.

• 한국지열·수열에너지학회논문집
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• 제14권4호
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• pp.43-52
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• 2018

This paper presents the cooling performance analysis results of a ground-source heat pump (GSHP) system using hybrid ground heat exchanger (HGHE). In this paper, the HGHE refers to the ground heat exchanger (GHE) using both a vertical GHE and a surface water heat exchanger (SWHE). In order to evaluate the system performance, we installed monitoring sensors for measuring temperatures and power consumption, and then measured operation data with 4 different load burdened ratios of the hybrid GHE, Mode 1~Mode 4. The measurement results show that the system with HGHE mainly operates in Mode 1 and Mode 2 over the entire measurement period. The average cooling coefficient of performance (COP) for heat pump unit was 5.18, while the system was 2.79. In steady state, the heat pump COP was slightly decreased with an increase of entering source temperature. In addition, the parallel use of SWHE and VGHE was beneficial to the system performance; however, further research are needed to optimize the design data for various load ratios of the HGHE.

• 설비공학논문집
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• 제29권9호
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• pp.455-462
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• 2017

The purpose of this study is to analyze heating and cooling load variation due to envelope retrofits in an old school building. In a previous study, envelope retrofit of an old school building resulted in annual energy consumption reduction. However, cooling energy consumption increased with the envelope retrofit. This is because of high internal heat generation rates in school buildings and internal heat cannot escape through windows or walls when the envelope's thermal performance improves. To clarify this assumption, thermal performance changes due to envelope retrofits were analyzed by simulation. Results revealed indoor temperature and inner window surface temperature increased with high insulation level of windows. Indoor heat loss through windows by conduction, convection and radiation decreased and resulted in an increase of cooling load in an old school building. From results of this study, energy saving impact of envelope retrofits in an old school building may not be significant because of high internal heat gain level in school buildings. In case of replacing windows in school buildings, local climate and internal heat gain level should be considered.

• 한국태양에너지학회 논문집
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• 제34권1호
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• pp.58-63
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• 2014

A vertical closed loop ground source heat pump (GSHP) is used to produce heat from the low-grade energy source such as the outside air and ground source. It is known that a heat pump system type has better efficiency comparing to the electric heating system. This study only demonstrates that the vertical closed loop GSHP system is a feasible choice for space cooling of air conditioning. The coefficient of performance (COP) is the ratio of heat output to work supplied to the system in the form of electricity. For the vertical closed loop GSHP system in a cooling mode, the COP is the most commonly used way for judging the efficiency. For the purpose of this experiment, vertical closed loop GSHP system was installed in the laboratory and the experiment was executed. As a result, an average COP of vertical-closed loop GSHP system was 3.62 when the outside average temperature was $33^{\circ}C$.

• 한국지열·수열에너지학회논문집
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• 제12권4호
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• pp.27-32
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• 2016

It is estimated that only heating and cooling take about one third of the total energy consumption worldwide. However, the conventional heating and cooling systems have low efficiencies. Also, boilers and electric heaters that are mostly used to generate both domestic and industrial hot water are inefficient and high energy consumers. For this reason, cascade heat pumps which are known to be very energy efficient and have less environmental impact are being promoted to replace conventional heating, cooling and hot water systems. In this study, a newly designed cascade heat pump by two-stage water heating method has been experimentally investigated. By adopting the auxiliary heat exchanger, the performance of the system was increased. The performance enhancement rate of the system could be maximized by adjusting the low stage compressor speed rather than the high stage compressor speed. The performance of the system with the auxiliary heat exchanger was enhanced by 16.5%.

• 설비공학논문집
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• 제25권1호
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• pp.1-6
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• 2013

This study aims to reduce cooling energy by grasping kinds of heating load in building in order to decrease cooling energy in summer and eliminate efficiently heating load. Lighting heating value was confirmed through examination and experiment concerning lighting heating and reducible exhaustion value was extracted lighting apparatus. The optimal exhaust system by air conditioning type was suggested for applying lighting heat exhaust system and the method contributing to promotion supplying low energy architecture was suggested by predicting reduced cooling load.

• 산업기술연구
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• 제43권1호
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• pp.15-23
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• 2023

Lithium-ion batteries are predominantly employed in electric vehicles and energy storage devices, offering the advantage of high energy density. However, they are susceptible to efficiency degradation when operated at high temperatures due to their sensitivity to the external environment. In this study, we conducted experiments using an indirect cooling method to prevent thermal runaway and explosions in lithium-ion batteries. The results were validated by comparing them with heat transfer simulations conducted through a commercial finite element analysis program. The experiments included single-cell exothermic tests and cooling experiments on a battery pack with 10 cells connected in series, utilizing 21700 lithium-ion batteries. To block external temperature influences, the experimental environment featured an extrusion method insulation in the environmental chamber. The cooling system, suitable for indirect cooling, was constructed with copper tubes and pins. The heat transfer analysis began by presenting a single-cell heating model using commercial software, which was then employed to analyze the heating and cooling of the battery pack.

• 설비공학논문집
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• 제30권4호
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• pp.159-166
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• 2018

The Korean fenestration energy consumption efficiency rating system only considers thermal performance of the heat transfer coefficient (U-value) and airtightness excluding optical characteristics of the solar heat gain coefficient (SHGC). This study analyzed annual heating and cooling energy requirements on the middle floor of apartment by optical and thermal performance of windows to evaluate the suitability of the rating system. One hundred and twenty-eight windows were analyzed using THERM and WINDOW 7.4, and energy simulation for a reference model of an apartment house facing south was performed using TRNSYS 17. The results showed that window performance was the main factor in the heating and cooling load. The heating load of the reference model was 539 kWh to 2,022 kW, and the cooling load was 376 kWh to 1,443 kWh. The coefficient of determination ($R^2$) of the heating and cooling loads driven from the SHGC were 0.7437 and 0.9869, which are more compatible than those from the U-value, 0.0558 and 0.4781. Therefore, it is not reasonable to evaluate the energy performance of windows using only the U-value, and the Korean fenestration energy consumption efficiency rating system requires a new evaluation standard, including SHGC.

• 설비공학논문집
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• 제23권6호
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• pp.449-469
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• 2011

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering during 2010. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) Research trends of thermal and fluid engineering have been surveyed as groups of general thermal and fluid flow, fluid machinery, and new and renewable energy. Various topics were presented in the field of general thermal and fluid flow. Research issues mainly focused on the thermal reliability of axial fan and compressor in the field of fluid machinery. Studies on the design of ground source heat pump systems and solar chemical reactors were executed in the field of new and renewable energy. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics and industrial heat exchangers. Researches on heat transfer characteristics included heat transfer in thermoelectric cooling/power generation systems, combined heat and power systems, carbon nano fluid with PVP, channel filled with metal foam and smoke ventilation in a rescue station of a railroad tunnel. Also the studies on flow boiling of R123/oil mixture in a plain tube bundle and R410A charge amount in an air cooled mini-channel condenser were reported. In the area of industrial heat exchangers, researches on plate heat exchanger, shell and tube heat exchanger, enthalpy exchanger, micro channel PCHE were performed. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics and industrial heat exchangers. Researches on heat transfer characteristics included heat transfer in thermoelectric cooling/power generation systems, combined heat and power systems, carbon nano fluid with PVP, channel filled with metal foam and smoke ventilation in a rescue station of a railroad tunnel. Also the studies on flow boiling of R123/oil mixture in a plain tube bundle and R410A charge amount in an air cooled mini-channel condenser were reported. In the area of industrial heat exchangers, researches on plate heat exchanger, shell and tube heat exchanger, enthalpy exchanger, micro channel PCHE were performed. (3) Refrigeration systems with alternative refrigerants such as hydrocarbons, mixed refrigerants, and CO2 were studied. Performance improvement of refrigeration systems are tried applying various ideas of refrigerant subcooling, dual evaporator with hot gas bypass control and feedforward control. The hybrid solar systems combining the solar collection devices with absorption chillers or compression heat pumps are simulated and studied experimentally as well to improve the understanding and the feasibility for actual applications. (4) Research trend in the field of mechanical building facilities has been found to be mainly focused on field applications rather than performance improvements. Various studies on heating and cooling systems, HVAC facilities, indoor air environments and energy resources were carried to improve the maintenance and management of building service equipments. In the field of heating and cooling systems, papers on a transformer cooling system, a combined heat and power, a slab thermal storage and a heat pump were reported. In the field of HVAC facilities, papers on a cooling load, an ondol and a drying were presented. Also, studies on HVAC systems using unutilized indoor air environments and energy resources such as air curtains, bioviolence, cleanrooms, ventilation, district heating, landfill gas were studied. (5) In the field of architectural environment and energy, studies of various purposes were conducted such as indoor environment, building energy, renewable energy and green building. In particular, renewable energy and building energy-related researches have mainly been studied reflecting the global interest. In addition, many researches which related the domestic green building certification of school building were performed to improve the indoor environment of school.