• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.301-312
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• 1999

Experiments were carried out to evaluate performance of the cold air distribution systems with an ice storage tank in test room. Cold air distribution systems provide primary air for comfort conditioning or process cooling at coil discharge temperatures$4^{\circ}C$ to$11^{\circ}C$. The application of a cold air distribution system allows for the downsizing of air distribution equipment and central plant equipment when ice storage tank is used. The benefit of a cold air distribution system include a decrease in the floor-to-floor height, increase floor space, reduced building capital costs, reduced energy use and demand. The use of cold air distribution can result in the most cost effective system and is currently being implemented world wise as the new standard in air conditioning systems. In this study, the cold air distribution system is compared with the general ice storage system. Under the same cooling load conditions, experimental results show that the supply air volume of cold air distribution system decrease 38%, and decrease 45% flow rate of brine for the general ice storage system.

• KIEAE Journal
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• v.10 no.6
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• pp.27-32
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• 2010

Approximately 20 percentage of energy consumptions in buildings is consumed as lighting energy. Thus, most of the corporations of lighting fixture have launched low energy products. However, many researchers focused on the only luminous efficacy for energy conservation and used the evaluating tool of study. This can not gauge the precise cooling load related on generated heat of artificial lighting. In order to assess an effect of the temperature variation of lighting resources, the main purpose of this study is to predict the generated heating energy from lighting by measuring the thermal variation in scale model to reduce external noise. Also this paper used MX100 data logger to record at an interval of 1 minute for 60 minutes for the temperature of interior lightings such as incandescent lamp, fluorescent light, halogen lamp and LED lamp. As a result, LED lamp generated the lowest heat. On the other hand, incandescent lamp did the highest.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.2
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• pp.86-96
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• 2010

The paper describes development and evaluation of a simple method for determining gradient of modified linear setpoint variation to reduce peak electrical cooling demand in buildings using building precooling and setpoint adjustment. The method is an approximated approach for minimizing electrical cooling demand during occupied period in buildings and involves modified linear adjustment of cooling setpoint temperature between $26^{\circ}C$ and $28^{\circ}C$. The gradient of linear variation or final time of linear increase is determined based on the cooling load shape in conventional cooling control having a constant setpoint temperature. The potential to reduce peak cooling demand using the simple method was evaluated through building simulation for a calibrated office building model considering four different weather conditions. The simple method showed about 30% and 20% in terms of reducing peak cooling demand and chiller power consumption, respectively, compared to the conventional control.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2007.10a
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• pp.247-256
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• 2007

Accessibility is a field of study that has primarily been applied to urban or transportation problems two dimensionally. However, in large complex buildings as shopping centers or hospitals, inter-spatial accessibility among compartments has to be taken into account such as in building layouts or evacuation planning. This study expands space syntax theory, one of accessibility-related methodologies used for computing connectivity in urban or architectural spaces, into 3D indoor spaces. Although space syntax is basically a topology-based theory that does not consider general costs such as distance or time, this study suggests modification that incorporates different types of impedances in moving between places including distances, turns and transfers between floors. The proposed method is applied to a 3D campus building model in computing and displaying the accessibility to exit doors or cohesive accessibility among similar functions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.1
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• pp.14-19
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• 2013

The present study has been conducted for evaluating and comparing the performance of the underfloor air distribution system(UFAD) and the ceiling based air distribution system(CBAD) under cooling condition. Simulations and experiments were carried out for verifying the model by TRNSYS program about UFAD and CBAD. The results of simulation for various conditions of thermal load are summarized as followings. UFAD had an advantage for making thermal comfort because of lower temperature of the floor surface. Moreover, UFAD showed lower fan power about 30~50% than CBAD under the same conditions of thermal load. The energy saving rates of UFAD were increased to 17.7% in proportion to the thermal load on unoccupied zone(lighting). Ultimately, additional investigations should be done for analyzing optimized operating conditions of UFAD with considering the thermal performance of building envelop and the thermal load.

• Journal of the Korea Concrete Institute
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• v.26 no.1
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• pp.13-21
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• 2014

To quantitatively evaluate the influence of ground granulated blast-furnace slag (GGBS) as a supplementary cementitious material on the life-cycle environmental impact of concrete, a comprehensive database including 3395 laboratory mixes and 1263 plant mixes was analyzed. The life-cycle assesment studied for the environmental impact of concrete can be summarized as follows: 1) the system boundary considered was from cradle to pre-construction; 2) Korea life-cycle inventories were primarily used to assess the environmental loads in each phase of materials, transportation and production of concrete; and 3) the environmental loads were quantitatively converted into environmental impact indicators through categorization, characterization, normalization and weighting process. The life-cycle environmental impacts of concrete could be classified into three categories including global warming, photochemical oxidant creation and abiotic resource depletion. Furthermore, these environmental impacts of concrete was significantly governed by the unit content of ordinary portland cement (OPC) and decreased with the increase of the replacement level of GGBS. As a result, simple equations to assess the environmental impact indicators could be formulated as a function of the unit content of binder and replacement level of GGBS.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.6
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• pp.1-8
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• 2005

The quantity of light available for a space can be translated in term of the amount of energy savings through a process of a building energy simulation. To get significant energy savings in general illumination, the electric lighting system must be incorporated with a daylight - activated dimmer control. A prototype configuration of an once interior has been established and the integration between the building envelope and lighting and HVAC systems is evaluated based on computer modeling of a lighting control facility. First of all, an energy-efficient luminaire system is designed and the lighting analysis program, Lumen-Micro 2000 predicts the optimal layout of a conventional fluorescent lighting future to meet the designed lighting level and calculates unit power density, which translates the demanded met of electric lighting energy. A dimming control system integrated with the contribution of daylighting has been applied to the operating of the artificial lighting. Annual cooling load due to lighting and the projecting saving amount of cooling load due to daylighting under overcast diffuse sky m evaluated by computer software ENER-Win. In brief, the results from building energy simulation with measured daylight illumination levels and the performance of lighting control system indicate that daylighting can save over 70 percent of the required energy for general illumination in the perimeter zones through the year A 25[%] of electric energy for cooling and almost all off heating energy may be saved by dimming and turning off the luminaires in the perimeter zones.

• Journal of Bio-Environment Control
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• v.8 no.2
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• pp.136-146
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• 1999

A series of experiments were carried out in winter to investigate the indoor thermal environment in greenhouses with different kinds of heating systems, and characterize the energy consumption, heat transport and thermal energy efficiency of each system. By the Quantitative calculation of heat losses which transmit through the covers of greenhouse, the fundamental data of energy-saving of the particular heating system were obtained. And from the analysis of air temperature differences between indoor and outside, it was possible to select more effective energy-saving and comfortable heating system in greenhouses. The electric heater was more stable in thermal environment and cheaper in cost, since it could be used during the surplus time of electric power from 10：00 p.M. to 8：00 A.M. But the low air temperature in greenhouses besides these times resulted in a chilling problem of the crops. The heating system by hot air had the advantage to show nearly uniform temperature difference by the height above the ground. But the system had the disadvantage to require more energy consumption than the electric heating system.

• The Journal of Engineering Geology
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• v.22 no.3
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• pp.275-281
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• 2012

Thermal distribution in soils must be considered in engineering designs and constructions, including estimates of frost heave and thaw settlement, infrastructure in cold regions, and geothermal systems. Because thermal conductivity is a key parameter for evaluation of thermal distribution in soils, it must be accurately estimated. The thermal conductivity of fine-grained soils has been widely studied in recent years; however, few studies have reported a reliable method for experimental measurement. The present study presents the results of an experimental investigation of the thermal conductivity of a saturated kaolinite-silica mixture with respect to the variation of dry density. Thermal conductivities were measured in Constant Rate of Strain (CRS) consolidation tests, and the experimental data were analyzed to evaluate the accuracy of the new measurement system. In addition, we present an evaluation method for predicting thermal conductivity in fine-grained soils.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.489-497
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• 2006

The feasibility of the Natural and Ecological Wastewater treatment System (NEWS) was examined for rural wastewater treatment in Korea. The intermittent trickling biofilter with high hydrophilic filter media was used for pretreatment for suspended solids and organic pollutants. The subsequent constructed wetland with porous granule materials was used for promoting nutrient removal. The results show that the removal efficiencies of the system were high with respect to the water quality parameters except COD. Even if the effluent from the biofilter did not meet the guidelines for wastewater treatment plant effluent in Korea in terms of $BOD_5$ and TN, the final effluent of the system meets the guidelines us to good performance of the constructed wetland. The regression analysis between pollutant loading rate and removal rate indicated that the system could have stable removal for SS, $BOD_5$, TN, and TP in the given influent ranges. The analysis in the winter period indicated that the wetland covered with transparent polycarbonate glass had the statble performance during the winter period dus to increase of temperature inside the wetland without any heating system. With the stable performance, effective poilutant removal, low maintenance, and cost-effectiveness, the NEWS could be considered as an alternative treatment system for decentralized regions and rural communities in Korea.