• 설비공학논문집
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• 제26권12호
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• pp.605-619
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• 2014

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. 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) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

• 설비공학논문집
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• 제20권12호
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• pp.844-861
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• 2008

The papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during the year of 2007 have been reviewed. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro nano fluid, micropump and fuel cell. Traditional CFD was still popular and widely used in research and development. Studies about fans and pumps were performed in the field of fluid machinery. Characteristics of flow and fin shape optimization are studied in the field of piping system. (2) The research works on heat transfer have been reviewed in the field of heat transfer characteristics, heat exchangers, and desiccant cooling systems. The research on heat transfer characteristics includes thermal transport in pulse tubes, high temperature superconductors, ground heat exchangers, fuel cell stacks and ice slurry systems. For the heat 'exchangers, the research on pin-tube heat exchanger, plate heat exchanger, condensers and gas coolers has been cordially implemented. The research works on heat transfer augmenting tubes have been also reported. For the desiccant cooling systems, the studies on the design and operating conditions for desiccant rotors as well as performance index are noticeable. (3) In the field of refrigeration, many papers were presented on the air conditioning system using CO2 as a refrigerant. The issues on the two-stage compression, the oil selection, and the appropriate oil charge were treated. The subjects of alternative refrigerants were also studied steadily. Hydrocarbons, DME and their mixtures were considered and various heat transfer correlations were proposed. (4) Research papers have been reviewed in the field of building facilities by grouping into the researches on heat and cold sources, air conditioning and air cleaning, ventilation and fire research including tunnel ventilation, flow control of piping system, and sound research with drain system. Main focuses have been addressed to the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies were mostly focused on analyzing the indoor environment in various spaces like cars, old tombs, machine rooms, and etc. in an architectural environmental field. Moreover, subjects of various fields such as the evaluation of noise, thermal environment, indoor air quality and development of energy analysis program were researched by various methods of survey, simulation, and field experiment.

• 설비공학논문집
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• 제25권6호
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• pp.346-361
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• 2013

This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2012. 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. The conclusions are as follows : (1) The research works on thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and valves, fuel cells and power plants, ground-coupled heat pumps, and general heat and mass transfer systems. Research issues are mainly focused on new and renewable energy systems, such as fuel cells, ocean thermal energy conversion power plants, and ground-coupled heat pump systems. (2) Research works on the heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer, and industrial heat exchangers. Researches on heat transfer characteristics included the results for natural convection in a square enclosure with two hot circular cylinders, non-uniform grooved tube considering tube expansion, single-tube annular baffle system, broadcasting LED light with ion wind generator, mechanical property and microstructure of SA213 P92 boiler pipe steel, and flat plate using multiple tripping wires. In the area of pool boiling and condensing heat transfer, researches on the design of a micro-channel heat exchanger for a heat pump, numerical simulation of a heat pump evaporator considering the pressure drop in the distributor and capillary tubes, critical heat flux on a thermoexcel-E enhanced surface, and the performance of a fin-and-tube condenser with non-uniform air distribution and different tube types were actively carried out. In the area of industrial heat exchangers, researches on a plate heat exchanger type dehumidifier, fin-tube heat exchanger, an electric circuit transient analogy model in a vertical closed loop ground heat exchanger, heat transfer characteristics of a double skin window for plant factory, a regenerative heat exchanger depending on its porous structure, and various types of plate heat exchangers were performed. (3) In the field of refrigeration, various studies were executed to improve refrigeration system performance, and to evaluate the applicability of alternative refrigerants and new components. Various topics were presented in the area of refrigeration cycle. Research issues mainly focused on the enhancement of the system performance. In the alternative refrigerant area, studies on CO2, R32/R152a mixture, and R1234yf were performed. Studies on the design and performance analysis of various compressors and evaporator were executed. (4) In building mechanical system research fields, twenty-nine studies were conducted to achieve effective design of mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, renewable energy systems, and lighting systems in buildings. New designs and performance tests using numerical methods and experiments provide useful information and key data, which can improve the energy efficiency of buildings. (5) In the fields of the architectural environment, studies for various purposes, such as indoor environment, building energy, and renewable energy were performed. In particular, building energy-related researches and renewable energy systems have been mainly studied, reflecting interests in global climate change, and efforts to reduce building energy consumption by government and architectural specialists. In addition, many researches have been conducted regarding indoor environments.

• 설비공학논문집
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• 제19권1호
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• pp.94-131
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• 2007

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2004 and 2005 has been done. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD and flow visualization(PIV, PTV and LDV methods) technologies were widely applied for developing facilities and their systems. (2) The research trends of the previous two yews are surveyed as groups of natural convection, forced convection, electronic cooling, heat transfer enhancement, frosting and defrosting, thermal properties, etc. New research topics introduced include natural convection heat transfer enhancement using nanofluid, supercritical cooling performance or oil miscibility of $CO_2$, enthalpy heat exchanger for heat recovery, heat transfer enhancement in a plate heat exchanger using fluid resonance. (3) The literature for the last two years($2004{\sim}2005$) is reviewed in the areas of heat pump, ice and water storage, cycle analysis and reused energy including geothermal, solar and unused energy). The research on cycle analysis and experiments for $CO_2$ was extensively carried out to replace the Ozone depleting and global warming refrigerants such as HFC and HCFC refrigerants. From the year of 2005, the Gas Engine Heat Pump(GHP) has been paid attention from the viewpoint of the gas cooling application. The heat pipe was focused on the performance improvement by the parametric analysis and the heat recovery applications. The storage systems were studied on the performance enhancement of the storage tank and cost analysis for heating and cooling applications. In the area of unused energy, the hybrid systems were extensively introduced and the life cycle cost analysis(LCCA) for the unused energy systems was also intensively carried out. (4) Recent studies of various refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and of alternative refrigerants including carbon dioxide. Efficiency of various compressors and expansion devices are also dealt with for better modeling and, in particular, performance improvement. Thermoelectric module and cooling systems are analyzed theoretically and experimentally. (5) According to the review of recent studies on ventilation systems, an appropriate ventilation systems including machenical and natural are required to satisfied the level of IAQ. Also, an recent studies on air-conditioning and absorption refrigeration systems, it has mainly focused on distribution and dehumidification of indoor air to improve the performance were carried out. (6) Based on a review of recent studies on indoor environment and building service systems, it is noticed that research issues have mainly focused on optimal thermal comfort, improvement of indoor air Quality and many innovative systems such as air-barrier type perimeter-less system with UFAC, radiant floor heating and cooling system and etc. New approaches are highlighted for improving indoor environmental condition as well as minimizing energy consumption, various activities of building control and operation strategy and energy performance analysis for economic evaluation.

• KIEAE Journal
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• 제12권4호
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• pp.89-95
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• 2012

At present, many countries are trying to reduce green gas emissions to mitigate the effects of these gases on climate change. Year after year, there have been efforts to cut energy use for heating and cooling. Heating and cooling systems, common in all forms of housing, are increasing due to the constant supply of new housing resulting from improvements in economic growth and the quality of life. Thus, studies related to the design of cooling and heating systems to improve energy efficiency are expanding. Among the new designs, radiant floor cooling and heating systems which use capillary tubes are becoming viable means of reducing energy use. Radiant floor cooling and heating systems which use capillary tubes are creative and sustainable systems in which cool and hot water is circulated into capillary tube which has small diameter. In this study, the cooling and heating performance of this type of capillary tube system is investigated in an experimental study and a simulation using TRNSYS. The results of the experimental study show that under a peak load, a capillary tube radiant floor cooling system using geothermal energy can achieve desired indoor temperature without an additional heat source. The set room air temperature is maintained while the floor surface temperature, PMV and PPD remain within the comfort range. Also, this system is more economic than a packaged air conditioner system due to its higher COP. The results of the simulation show that the capillary tube radiant floor heating system maintains set temperature more stable than a PB pipe radiant floor heating system due to its lower supply temperature of hot water. In terms of energy consumption, the capillary tube radiant floor heating system is more efficient than the PB pipe radiant floor heating system.

• 한국실내디자인학회논문집
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• 제24권6호
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• pp.3-12
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• 2015

Recently, the spatial design of resting spaces in department stores has been changed. The design elements such as colors, materials, lighting, natural elements, furniture arrangement, and VMD are not only providing a pleasant and natural indoor atmosphere in resting spaces but also providing various services to customers. In this study, it aims to analyze how the spatial design characteristics of resting spaces in department stores are appeared. The results are as follows. First, the spatial characteristics of the resting spaces in department sores came up as five factors; accessibility, recognition, comfort, convenience, and esthetics. As the result, the accessibility is the most important factor in resting spaces. Second, the resting spaces was well located near by the elevators and escalators providing easy accessibility to customers to floor. Third, the resting spaces need to improve the spatial design for emphasizing the recognitions by using colors, materials and lighting. Fourth, the resting spaces were provided different atmosphere by their location. Fifth, the various forms of furniture, curved, zigzagged, and cubed, were placed in the resting spaces for comport use. Sixth, the aesthetic was the least important factor of all. To improve this problem, the resting spaces need to provide cultural contents by installing art pieces, moving picture facilities, and VMD. Seven, most of the resting spaces had similar floor plan type that they did not perform their role successfully. The resting spaces need to provide both individual rooms and unique open spaces for giving a choice to use when customers visit them.

• 한국실내디자인학회논문집
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• 제26권2호
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• pp.72-82
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• 2017

Current world population is rapidly ageing and the disabled population is expected to age seriously as well. The concern about the elderly and the disabled is increased largely not just the field of social welfare and service but the housing planning where the physical environment of everyday life is. Recently in Ireland, 'Universal Design Guideline for Homes' is established and proposed in public. It is considered as initial and special national policy for the socially venerable. The purpose of this research is to analyze the User Benefit Characteristics(UBC) of 'Universal Design Guideline for Homes in Ireland' and clearly organize the characteristics for comprehensive communication. The research subjects are 444 guidelines of 'Universal Design Guideline for Homes in Ireland.' The research is conducted by contents analysis technique, and each guideline is analyzed by the 4 main concepts of UBC- 'Behavioral Facilitation(BF)', 'Physiological Maintenance(PhM)', 'Perceptual Maintenance(PM)', 'Social Facilitation(SF).' As results, the User Benefit Characteristic of 'Universal Design Guideline for Homes in Ireland' is ordered by PhM>PM>BF>SF. The design guidelines are supposed to support ageing in place and sustainable living in the existing houses even though people are ageing or being disabled. 'Universal Design Guideline for Homes in Ireland' supports safe behavior and comfort cognition especially in indoor and surrounding outdoor environment. This research is significant for sharing the knowledge and comprehension of decreasing environmental stress of the elderly in specific, and could be utilized for developing new elderly housing in future.

• 한국해양환경ㆍ에너지학회지
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• 제8권1호
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• pp.31-38
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• 2005

본 연구에서는 PMV기반-공조시스템 설계를 위한 기초자료 조사를 목적으로 6가지 물리적/주관적 온열요소의 특성을 평가하였다. 물리적 온열요소의 평가에서는 25톤 함정의 조타실과 통신실, 100톤 함정의 기관실에서 열적 불만족이 발생할 수 있었다. 착의상태 및 활동상태 항목은 육상 실내건축의 내용을 선상 근무에 맞게 수정하여 이용하였다. 주관적 온열요소 중 의닦의 열 저항치는 모든 함정의 선실에서 승조원 사이의 편차가 커서 신진대사량에 비해 온열평가에 미치는 영향이 더 민감한 것으로 나타났다. 주관적 온열요소의 분포는 대체로 표준 정규분포보다 오른쪽으로 꼬리가 긴 비대칭분포를 보였다.

• KIEAE Journal
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• 제14권4호
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• pp.111-117
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• 2014

In South Korea, the government has recently enforced regulations associated with buildings. Temperature restriction in indoor environment is one of the common ways of energy reduction in order not to dissipate heating and cooling energy; however the people who are in restricted temperature feels uncomfortable. Furthermore, occupants cannot feel the same thermal sensation even they are in the same place. For the reason, occupants should express their thermal sensation and HVAC system should be able to apply their demand. It is proved by an adaptive principle. The adaptive model means that people react in ways which tend to restore their comfort, when change occurs such as to produce discomfort. In order to design HVAC control strategies based on adaptive model, we designated an existing office building as a reference building to gather data from actual field. Furthermore, we gathered occupants' thermal sensation and clothing insulation in real-time. We filtered the data with Kalman's filter method. The data was reasonable when there is an alarm messages for asking questionnaire. The response ratio were different in occupants' thermal condition. In conclusion, the filtered occupants' thermal sensation can be used as a real time HVAC control and input value of HVAC control.

• 대한치과기공학회지
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• 제33권4호
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• pp.379-390
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• 2011

Purpose: This study was conducted to improve the working conditions of dental technicians, through survey for working conditions related to perform one's duty, the extent of personal exposure to substances hazardous and complaint rate and factor of job stress and subjective symptom on musculoskeletal disorders. Methods: Using four types of structured questionnaires: social and demographic factor; the actual conditions of working space; working conditions; and characteristics of dental technicians, respondents filled in the questionnaires and the results were analyzed statistically. Results: The evaluation of comfort in working place found that satisfaction level on indoor noise was the lowest with 2.6 on a five-point scale and privacy space followed 2.8 point. In reasons for dissatisfaction with job, over workload ranked the highest by 25.4% and role overload had the highest by 39.5% in job stress factors. Based on the results, we could draw conclusion that dental technicians were unsatisfied with role overload and heavy workload a day. In reasons for musculoskeletal symptom prevalence, long-patient work was the highest by 24.1%. It was thought to cause dental technicians need deep procession and long-patient work due to the nature of their job. Conclusion: In conclusion, noise reduction and privacy space are required to improve job efficiency of dental technicians. In addition; we need to think of ways to increase the job satisfaction with adequate rest while deep procession and long-patient working.