• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.43-50
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• 2007

In recent years the importance of the preservation of cultural artifacts like ancient tombs has been widely accepted domestically and internationally with increasing value of cultural artifacts. However not much technical attention has been paid for the facilities and systems to preserve these artifacts. As a part of the present study, the temperature and relative humidity inside a selected artifact, Shinkwan-ri tomb, have been monitored for a year round to improve the understanding of the indoor thermal environment. In this study, using the Computational Fluid Dynamics calculated the velocity and temperature distribution and offered basic data which are necessary for the best fitted design of tomb air-conditioning device. Through the result of this study, the generation of temperature variation was identified by natural convection. It enables us to get the possibility of humidity variation

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.4
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• pp.213-220
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• 2016

The objective of this study is to investigate the cooling performance of an air-conditioning system for a special purpose vehicle under tropical and severe weather conditions. In order to evaluate and compare the cooling performances, the dual refrigeration cycle using R-134a was tested on a special purpose vehicle with various refrigerant charge amounts and indoor temperatures. The cycle was tested considering indoor cooling speed and compression ratio (discharge pressure), and was optimized at the refrigerant charge amount of 1.5 kg and outdoor temperature of $40.0^{\circ}C$. The time to reach indoor temperature of $15.0^{\circ}C$ increased by 86.5% and 38.1%, at the indoor temperatures from $25.0^{\circ}C$ to $32.5^{\circ}C$ and from $32.5^{\circ}C$ to $40.0^{\circ}C$, respectively. In addition, with the increase in indoor temperature from $25.0^{\circ}C$ to $40.0^{\circ}C$, the cooling capacity increased by 7.3%, from 19.1 kW to 20.5 kW, but decreased by 7.0% from 4.67 to 5.1.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.10
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• pp.4308-4313
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• 2011

The objective of this study is to investigate the cooling performance of the roof mounted air-conditioning system using electric driven scroll compressor for zero emission vehicles. This air conditioner with air source was used R-134a as a refrigerant and tested under various operating conditions such as refrigerant charge amount and indoor temperature, and compressor frequencies. Experimental results revealed that at all tested compressor frequencies, heat transfer rate of the evaporator increased and the cooling COP increased with the indoor temperature. In addition, the heat transfer rate of the evaporator was over 25.0kW sufficient for the cooling loads of an electric bus.

• Journal of the Korean housing association
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• v.27 no.6
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• pp.31-43
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• 2016

The purpose of this paper is to gather information and opinions to better guide the direction for implementing improvements of the senior centers' indoor environments located in Jeonju residential areas, by surveying the users about the level of satisfaction and analyzing the result in relation to the current situation. Senior centers located in Jeonju residential areas were operating the facilities with low financial support from the local autonomous entity. According to the results of the survey, most of the users tend to use the facilities between 12p.m. to 6p.m., and the majority have lunch at the senior centers. Most of the senior centers already have cooking facilities, without a dining room, except one place, and even the facilities they have are very poor. In a thermal environment area, the temperature is mostly above in summer or below in winter the appropriate temperature, especially the temperature of the restroom of all senior centers are below $20^{\circ}C$ in winter. The density of carbon dioxide is above average in most indoor areas. However, the users' level of facilities' satisfaction was positive. To improve the seniors' quality of life, the local autonomous entity has to start regular check-ups and repair of the poor indoor environment and facilities, with more financial support and active supervision by senior center the management.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.77-85
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• 2007

One of the most common approaches to achieve better thermal comfort with the radiant floor heating system is supply water temperature control, which is that supply water temperature is varied with outdoor air temperature. But the application of this control method was not easy, because there has been no way to determine the supply water temperature. So in this study, a comprehensive, yet simple calculation method to find out the required supply water temperature is suggested by combining the building heat loss equation and the heat emission model of hydronic radiant floor heating system for single zone. And then using this calculation method, the multizone control method is suggested and confirmed through the thermal simulation. It is shown that indoor air temperature is stably maintained around the set point.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.210-217
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• 2011

Recently, research on evaluating thermal comfort by using CFD has been vigorously active. This research evaluates not only distribution of temperature and air flow analysing but also thermal comfort in indoor space by applying human model. But research of human model's shape, Grid characteristic and turbulence model has not yet been studied. In this paper, human model's shape, physical characteristic of variable Grid, and change of turbulence model has been studies by CFD. In this study. FLUENT is used for analysis and PMV(predicted Mean Vote), PPD(Predicted Percentage Dissatisfied) and EHT(Equivalent Homogeneous Temperature} are used for evaluation and comparison of thermal comfort. As a result, it shows that shape of CSP and lattice features does not affect on global flow field or evaluation on PMV, PPD. However, it demonstrates more precise result from evaluation of thermal comfort by equivalent temperature when it used detailed human model considering prism grid.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.8
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• pp.325-330
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• 2016

This study was conducted to develop a heating system for a fuel cell-driven electric vehicle. The system consists of a compressor, an expansion device and three heat exchangers. A conventional air source heat exchanger is used as primary heat exchanger of the system, and an additional water source heat exchanger is used as a pre-heater to supply heat to the upstream air of the primary heat exchanger. On the other hand, the third heat exchanger consists of a water-to-refrigerant heat exchanger. The heat source of the pre-heater and the water-refrigerant heat exchanger is the waste heat from the fuel cell's stack. In the experiment, the indoor and the outdoor air temperature were fixed, and the compressor speed, EEV opening and waste heat temperature were varied. The results indicate that the $COP_h$ of the proposed system is 3.01 when the system is operating at a 1,200 rpm compressor speed, 50% EEV opening, and $50^{\circ}C$ waste heat source temperature in air pre-heater operation. However, when the system uses a water-refrigerant heat exchanger, the $COP_h$ increases to up to 9.42 at the same compressor speed and waste heat source temperature with 75% EEV openings.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.8
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• pp.627-635
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• 2012

This study aims at developing an artificial neural network(ANN)-based predictive and adaptive temperature control method to control the openings at internal and external skins, and heating systems used in a building with double skin envelope. Based on the predicted indoor temperature, the control logic determined opening conditions of air inlets and outlets, and the operation of the heating systems. The optimization process of the initial ANN model was conducted to determine the optimal structure and learning methods followed by the performance tests by the comparison with the actual data measured from the existing double skin envelope. The analysis proved the prediction accuracy and the adaptability of the ANN model in terms of Root Mean Square and Mean Square Errors. The analysis results implied that the proposed ANN-based temperature control logic had potentials to be applied for the temperature control in the double skin envelope buildings.

• Journal of Biosystems Engineering
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• v.23 no.6
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• pp.599-606
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• 1998

This study was carried out to develop the control system with PLC and its operating software and to investigate its control ability of greenhouse environments. Two experimental greenhouses were controlled by PLC and ON/OFF controller, respectively. In greenhouse controlled by PLC, target values of air temperature, relative humidity and $CO_2$ concentration were automatically changed. In warm-water heating, the variation of air temperature was reduced to $\pm$ $0.6^{\circ}C$ by the method of proportional-integration(PI) control with an inverter. In ventilation, the variation of air temperature was reduced, since windows open and close with multistage by mutual relation formula among the target, indoor, and outdoor temperature. Relative humidity at daytime was maintained with range of 35% to 55% by PLC controlled fogger. $CO_2$ concentration was automatically controlled from 300 to 800 $\mu$molㆍ$mol^{-1}$ according to amount of solar radiation. The suppling amount and frequency of nutrient solution were controlled by total integrated solar radiation. Difference in the yield of cucumber in the greenhouse controlled by PLC and by ON/OFF controller was not significant at the 5% level.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.708-713
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• 2008

Various kinds of contaminant are generated from many kinds of interior construction materials, furniture and life articles. People of today living indoor most of the time are exposed to these kinds of contaminant. In this connection, people are exerting their efforts to reduce the occurrence of contaminant from the interior finish materials. And it is the actual condition that research is being actively made on the method of reducing contaminant by performing bake-out for newly constructed housings. Bake-out is the method of temporarily increasing the generation of the harmful contaminant quantity including VOCs and Formaldehyde emitting from construction materials or finish materials by increasing the interior temperature of the newly constructed buildings or improved or repaired buildings, and then removing it by mobilizing ventilation system. In this study, the researcher measured the effect of reduced concentration according to ventilation or non-ventilation of the newly constructed but not yet resident public housings during the bake-out in order to grasp the effect of reduced interior air contaminant according to the elapse of timeat the time of bake-out.