• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.205-208
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• 2006

This paper proposes a new computational aeroacoustics method for an axial fan analysis. The major aeroacoustic noise source of an outdoor air-conditioner is the axial fan. It was revealed that the dominant noise source is the aerodynamic interactions between the rotating blade and stationary orifice. Many researches were focused on the fan only case. However, it does not fit to a real outdoor unit of air-conditioner. Especially, the inlet part of the axial fan of real system case is complex and not uniform. So, in order to identify the dominant noise source of axial fan, full outdoor unit analysis is important. Transient CFD analysis of full system was performed by commercial CFD code - SC/Tetra. Dominant noise source of the system was calculated by commercial CFN code - FlowNoise. The results show that not only BPF peaks but also broadband noise are similar to the measured data.

• 설비공학논문집
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• 제24권1호
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• pp.70-76
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• 2012

The purpose of this study is to analyze of the operating characteristics of the Gas engine driven Heat Pump(GHP) and to reduce maintenance costs through the most Economical plan. As the zoning modifications that have economic effects were confirmed. Applications should be made with a similar purpose of the space. The combination of a modified space has led to reduced operating hours of the outdoor unit. The reduction of the outdoor unit operating hours, reducing maintenance costs accordingly. When analyzed at six years have elapsed, the amount of savings through zoning modifications is more than an additional construction cost. During the design phase, cost-effective operation of the GHP is required for the proper zoning plan.

• 한국응용과학기술학회지
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• 제37권5호
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• pp.1402-1408
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• 2020

에너지를 절감하기 위해 고효율 히트펌프를 개발하기 위한 많은 연구가 이루어지고 있으며, 실외기 코일에 발생하는 서리가 발생하는 현상을 줄이거나 없애기 위한 연구도 동시에 이루어지고 있다. 계절에 관계없이 히트펌프의 실외기에 서리가 발생하지 않는 연구를 진행할 수 있도록 자연상태와 동일한 조건에서 실험할 수 있는 항온챔버를 구축하였다. 실험장치의 타당성을 검증하기 위해 실험장치인 항온챔버 내의 실외기 앞 덕트의 직선 길이를 3가지 조건으로 나누어 시뮬레이션 하였다. 그 결과 덕트 관경의 10배 길이만큼 직선 공간을 확보해야 한다는 것을 알게 되었다.

• 설비공학논문집
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• 제20권11호
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• pp.718-726
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• 2008

The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. Hence, the development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the performance of a simultaneous heating and cooling heat pump was investigated in the heat recovery mode (HR mode). The system adopted a variable speed compressor using R410A with four indoor units and one outdoor unit. In the HR mode, the capacity and COP were improved as compared with those in the cooling or heating mode because the waste heat in the outdoor unit was utilized as useful heat in the indoor units. However, energy imbalance between heating and cooling capacity of each indoor unit was observed in the 2H-1C HR mode. Therefore, the performance of the system in the 2H-1C HR mode was enhanced by controlling refrigerant flow rate through the outdoor unit.

• 한국의류산업학회지
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• 제16권3호
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• pp.446-455
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• 2014

This study revealed the results related to the functionality of outdoor wear required when man and women in their 30s to 50s engage in outdoor activities. Based on the results of the survey, we proposed composition draft for a smart outdoor jacket with main functions of GPS device and light-emitting device using solar cell and EL. Absorption and release of sweat, functionality regarding rain and wind, and lightweightness, etc. from material functionalities of outdoor wear were found to be important. From function required in clothing for outdoor activity, location tracking, night glow, and lighting functions were found to be most important. For results investigating the necessity of the jacket's location tracking function and lighting function using solar cell, high scores of 3.9~4.0 were given. Purchase intentions for smart outdoor jacket with location tracking and lighting functions devised by this study were fairly positive and most responses indicated that the appropriate purchase price was between 200,000 to 300,000 won while possible problems of this smart outdoor jacket were listed in the order of washing inconvenience, high price, device weight, and discomfort in movement. The draft proposal to integrate with wearable devices for smart outdoor jacket prototype is as follows: Solar cell has been attached to the upper arm but placed inside a transparent pocket which has been detachable for washing convenience while the solar cell and controller have been integrated into a single unit. Using frequent movement exhibited by the arms, EL has been attached along the center line of the raglan sleeve for easy spotting when used as an emergency signal or for night lighting function during outdoor activity. GPS has been attached on the left sleeve so that the person can bend the left arm inward and operate the GPS screen with the right hand while walking or running outdoors.

• 한국생활과학회지
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• 제15권2호
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• pp.209-225
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• 2006

The purpose of this study is to research the actual condition of environment and management of outdoor play at child care centers in Seoul, and to present a planning guideline for outdoor play environment. For this purpose, data were collected by a structured questionnaire and subjects were 164 directors of child care centers located in Seoul. The contents of the questionnaire were composed of general facts about the respondent and facility, environmental condition, managerial condition, and director's understanding about outdoor play. The data were then analyzed using the frequency, percentage, mean and crosstab. The major results have shown the following: 1) Most child care centers in Seoul had some space for outdoor play. 62% of them used front yard and 11 % a rooftop. 2) The space usually included fixed play instruments such as slide and complex unit structures, sand play area, and open area. It also had many natural elements as shrubs and earth. 3) 78% of the centers had a schedule for outdoor play. The schedule operates flexibly according to each center's own day schedule. Generally, a time for outdoor play was 21 to 30 minutes. 4) The directors of child care centers thought highly of outdoor play for it contributes to the balanced development of children. They answered that equipments and spaces, program devices, and teacher's understanding are some of the important factors for active outdoor play. 5) Most of them wanted wood-working area (construction activity area), water play area, and cages.

• 한국산학기술학회논문지
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• 제16권1호
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• pp.762-768
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• 2015

본 연구의 목적은 최근 고층아파트 단지 내에서 주요 계획요소로 자주 채택되고 있는 저층부 필로티 공간과 주요 옥외단위공간들의 통합도 값을 단지별 전체 통합도 평균값과 비교하여 필로티 공간의 통합도 값이 다른 옥외공간들과 비교할 때 어느 정도의 통합도 위상을 갖는지 분석하는 것이며, 또한 다음 단계의 연구인 필로티 공간 이용행태 관찰 및 이용빈도 조사의 기초자료로 삼는데 있다. 본 연구의 결론은 다음과 같다. 첫째, 고층아파트 단지의 필로티 공간을 포함한 주요 옥외단위공간들 중 '단지출입구' 또는 '광장' 공간이 가장 높은 통합도 값을 보이고 있다. 둘째, 고층아파트 단지의 필로티 공간 통합도 값이 다른 주요 옥외단위공간들의 통합도 값보다 대체적으로 낮은 경향을 보이고 있다. 세째, 고층아파트 단지의 필로티 공간들중 동출입구의 기능이 없는 '돌출형 출입 + 필로티 부가형' 유형의 공간일 경우 주민들의 공간이용률이 현격하게 저조하여 음성적 공간화 및 공동화 현상이 발생될 가능성이 크다고 볼 수 있다.

• 한국정밀공학회지
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• 제34권2호
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• pp.133-138
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• 2017

Inverter-Type refrigerators are known to consume less energy by varying the inverter frequency according to indoor temperatures and refrigerant pressure through indoor-outdoor communication. However, many commercial operators cannot afford to replace indoor units with ones capable of communication. In a non-communication configuration, indoor units are connected with an inverter-type outdoor unit without intercommunication abilities. The research goal is finding appropriate operating parameters to achieve energy efficiency. Thus, an operation algorithm with two modes is proposed, i.e., one to search the best operating parameters and one for normal operation with the best parameters. The experimental evaluation showed 11.27% reduction in energy consumption, indicating a good applicability of the algorithm.

• KIEAE Journal
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• 제9권6호
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• pp.27-36
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• 2009

Lately construction companies are differentiating the outdoor spaces of apartment complexes to satisfy the needs of residents by providing underground parking area and variety of outdoor community spaces. Building walking networks through residential unit area, the major passage area and the entrance area of the complexes is very important factor to increase the use of the outdoor environment in the complexes. The purpose of this study is to evaluate the characteristics and the elements for the planning of exterior pedestrian spaces carefully through the analysis of current large-scale apartment complexes. In this study, the utilization of space, the connectivity to other spaces and the application of Universal design were evaluated through site visits in 5 large-scale apartment complexes. As a result, the utilization of space is well applied in the most of complexes especially in residential unit area. The connectivity to other spaces has low application compared to the others. Universal design is also well applied except sub criteria for the blind in most of complexes. This study will be able to help in providing better exterior pedestrian environment for residents in apartment complexes.

• 설비공학논문집
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• 제26권12호
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• pp.572-578
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• 2014

Heating energy was measured in an apartment housing unit with a district heating system, varying the kind of hot water distributors. Ondol coils passing through a living room raised the temperature of the room where the heating was turned off. Including this characteristic of Ondol heating into the modeling, we performed simulations and showed a verification by comparison with the results of measurements. As a result, a main flow control method, which changes hot water flow rate supplied to a housing unit according to the thermal load, can reduce the supplied flow rate and lower the return temperature, compared with a constant flow method. That can result in decreased heat loss in utility-pipe conduits even though the heating energy supplied is almost the same. An outdoor reset control that raises the temperature of the supplied hot water if the outdoor temperature falls has the effect of a quicker response in heating than the reduced flow rate and return temperature.