• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.618-622
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• 2007

In the present study, the cooling and heating operation characteristics of a multi-heat pump have been experimentally investigated for the number of the indoor units(A, B, C) and the operating conditions. The heat pump was controlled by an inverter scroll compressor. The performance of the heat pump was measured by the multi-calorimeter of an air enthalpy method. Cooling and heating capacities and COPs were obtained at the cooling and heating temperature conditions and the setting temperatures of an indoor unit. With increasing the operation frequency of the compressor, the cooling and heating capacities of the heat pump increased linearly. The operation frequency region of the compressor was different as the combination of the indoor unit and the cooling/ heating condition.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.578-583
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• 2006

This paper introduces conceptual design of scroll expander-compressor unit for fuel cell. Since air discharged out of the fuel cell stack after reaction has still high pressure energy, some power can be extracted out of it by directing it to pass through an expanding device so that the extracted power can be used to drive an auxiliary compressor. For this purpose, a scroll type expander coupled to a scroll type compressor was designed: orbiting scroll of the expander and that of the compressor were made to share three of common drive pins installed in the mid frame plate, and central cavity in the mid-plate was used as a back pressure chamber to provide axial compliance for both orbiting scrolls. Performance analysis for the expander showed that the shaft power of the expander could reduce the auxiliary power consumption in the fuel cell by about one third at the scroll clearance of $10{\mu}m$.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.108-113
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• 2009

Buildings with multi-complex spaces designed for architectural values and functional requirements give rise to technical challenges in terms of energy efficiency and thermal comfort. Since spaces in such buildings are connected with openings with geometrical complexity, it is hard to define zoning plan and to control heating/cooling loads effectively. This paper presents a case study on the evaluation of operation strategy for a building with multi-complex spaces using computer simulation. The modelling methodology and the results of the simulations are also described.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.925-930
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• 2008

As office automation appliances and communication equipments are adopted in office buildings, internal heat gains increase gradually. When making simulation model, internal heat gains are usually set up with standard values or ignored. Therefore, the impact of the internal heat gains has been ignored or not been focused although it is recognised as significant contributor to heating/cooling load of buildings. This study focused on the impact of internal heat gains on curtain wall buildings. the amount and schedules of heat internal gains profiles not only affect the profiles of heating/cooling loads, but also make impact on reducing the effectiveness of high performance glazing systems. It is important to identify internal heat gains profiles before considering the installation of high performance glazing systems.

• 융합신호처리학회논문지
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• 제23권3호
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• pp.123-128
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• 2022

에너지를 절약하기 위해 고효율 히트펌프를 개발하기 위한 많은 연구가 이루어지고 있으며, 실외기 코일에 발생하는 서리가 발생하는 현상을 줄이거나 없애기 위한 연구도 동시에 이루어지고 있다. 계절과 관계없이 히트펌프의 실외기에 서리가 발생하지 않는 연구를 진행할 수 있도록 자연 상태와 동일한 조건에서 실험할 수 있는 항온챔버를 구축하였다. 항온챔버 내에 설치된 히트펌프의 실외기에 자연 상태와 같은 환경을 제공하여 실험하였으며, 그 결과 외기온도가 낮을수록 히트펌프의 효율은 낮으며, 히트펌프 시스템의 운전이 안정화 상태에 도달하는 시간은 외기온도가 낮을수록 길어지는 것을 확인하였다.

• 융합신호처리학회논문지
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• 제24권3호
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• pp.140-146
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• 2023

에너지를 절약하기 위해 고효율 히트펌프를 개발하기 위한 많은 연구가 이루어지고 있다. 그 중, 실외기 코일에 발생하는 서리가 발생하는 현상을 줄이거나 없애기 위한 연구도 동시에 이루어지고 있다. 계절과 관계없이 히트펌프의 실외기에 서리가 발생하지 않는 연구를 진행할 수 있도록 자연 상태와 동일한 조건에서 실험할 수 있는 항온챔버를 구축하였다. 항온챔버 내에 설치된 히트펌프의 실외기에 자연 상태와 같은 조건으로 시뮬레이션하였으며, 그 결과 외기온도가 낮을수록 냉매의 질량유량은 감소하였으며, 냉매의 건도 역시 외기온도에 따라 선형적으로 증가함을 확인하였다.

• 대한기계학회논문집B
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• 제29권7호
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• pp.868-877
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• 2005

We performed the experimental and the numerical study on the comparison of thermal comfort performance indices for cooling loads in the lecture room for 4 cases: Fan coil unit(FCU) or 4-way cassette air-conditioner is respectively operated with the ventilation system or without. We measured the velocity, the temperature distribution and predicted mean vote(PMV) value in the lecture room for 4 different air-conditioning methods. Effective draft temperature(EDT) and PMV were investigated to analyze the characteristics of two thermal comfort indices in the lecture room and to compare their values each other. From the results we knew that there is the similarity between PMV values and EDTs when the room is air-conditioned for cooling loads. It turned out that definition of the control temperature is very important when the EDT is calculated. Finally EDT should not be used to predict the accurate thermal comfort in case that the temperature and humidity are suddenly varied and the zone affected by the solar and inner wall radiation.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.323-328
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• 2005

The objective of this study is to analyze the cooling performance of an air- cooling system for telecommunication equipment. Temperature variation and capacity were measured in an actual unit for telecommunication equipment. In addition, the cooling performance was measured by installing a silicon rubber heater as a heat source in a cabinet. The standard thermal load for telecommunication equipment was approximately 293 W, and the maximum temperature of the heated surface was $64.5^{\circ}C$. The average and maximum temperatures of the heated surface were proportional to the inlet air temperature. When the heat load increased from 293 W to 400 W, the maximum temperature of the heated surface was higher than $64.5^{\circ}C$ even though the inlet air temperature decreased from 25 to $11^{\circ}C$.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.70-76
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• 2003

An experimental study was performed to understand the heat transfer and fluid dynamic characteristics of Sub-Cooled Hybrid Condenser (SCHC), which conventional condenser and receiver dryer are integrated into. SCHC also employs a sub-cooled refrigerant passages at the end of the condenser in order to supply perfect liquid refrigerant to the expansion unit. Throughout the present study, it was found that the developed SCHC increases in the degree of sub-cooling by 10~100% compared to conventional condenser. The excessive sub-cooling has improved the cooling performance by 10%, and that leads reduction in evaporator outlet air temperature by $1.5^{\circ}C$. Also found through the study is that the refrigerant pressure drop across SCHC is fairly increased due to insertion of the desiccant cartridge in the receiver tank which is composed of zeolite, filter and supporter plate.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.701-705
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• 2009

After revision of law of architecture in 2006, all houses which have more 100 households must has ventilation unit for the indoor air quality. Optimal design of the natural and the mechanical ventilation has being considered. In this paper, it is carried out about optimal design for airflow distribution of total heat exchanger in houses using CFD. As the result, first design of ventilation has some problem in porch area. Adding diffusers in porch area and changing diffuser schedule make more efficient ventilation than original design.