• 한국산학기술학회논문지
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• 제16권6호
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• pp.4253-4259
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• 2015

본 연구에서는 자연외기를 활용하여 건물의 에너지절약을 위한 외기냉방제어 시스템에 대하여 다양한 제어방법에 따른 제어특성 및 에너지 소비량에 미치는 영향에 관해 시뮬레이션 연구를 수행하였다. 연구 방법으로는 TRNSYS 프로그램을 활용하여 시스템 해석 모델링을 수행하였으며, 외기 냉방을 하지 않은 경우와 기존의 외기냉방 제어방법들을 적용하였을 경우에 대해 제어성능에 대한 비교 분석이 이루어졌다. 연구 결과로 외기온도 변화에 따라 적절한 외기도입 온도조건을 선정하는 것이 에너지 절감에 효과적이며, 외기와 환기온도를 비교하여 온도제어하는 방법이 에너지 절감효과가 가장 크게 나타남을 알 수 있었다.

• 동력기계공학회지
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• 제18권5호
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• pp.150-155
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• 2014

This paper presents The performance analysis of inverter control type-industrial cooler with respect to refrigeration load and outdoor temperature. Aside from materials about simulations and foundation data regarding inverter control compressors, currently, data about commercial coolers with inverter control still lack information for performance comparison. Thus, in this paper, the experiments are done to see characteristics of condensation capacity, evaporation capacity, compressor power and COP with respect to outdoor temperature and load by using a commercial inverter control cooler model. As a result, COP difference of the inverter control cooler with respect to load is 30% at the outdoor temperature of $35^{\circ}C$, 29% at the outdoor temperature of $30^{\circ}C$, 34% at $25^{\circ}C$, respectively.

• 설비공학논문집
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• 제19권5호
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• pp.394-402
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• 2007

To estimate the cooling load for the following day, outdoor temperature and humidity are needed in hourly base. But the meteorological administration forecasts only maximum and minimum temperature. New methodology is proposed for predicting hourly outdoor temperature and humidity by using the forecasted maximum and minimum temperature. The correlations for normalized outdoor temperature and specific humidity has been derived from the weather data for five years from 2001 to 2005 at Seoul, Daejeon and Pusan. The correlations for normalized temperature are independent of date, while the correlations for specific humidity are linearly dependent on date. The predicted results show fairly good agreement with the measured data. The prediction program is also developed for hourly outdoor dry bulb temperature, specific humidity, dew point, relative humidity, enthalpy and specific volume.

• 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.

• 한국지열·수열에너지학회논문집
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• 제17권4호
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• pp.68-78
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• 2021

In order to solve the increasing deterioration of the energy shortage problem, ground-source heat pump (GSHP) systems have been widely installed. The control method is a significant component for maintaining the long-term performance and for reducing operation cost of GSHP systems. This paper presents the measurement and analysis results of the cooling performance of a GSHP system using capacity control with outdoor air temperature. For this, we installed monitoring equipments including sensors for measuring temperature, flow rate and power consumption, and then monitored operation parameters from July 9, 2021 to October 2, 2021. From measurement results, we analyze the effect of capacity control with outdoor air temperature on the cooling performance of the system. The average performace factor (PF) of the heat pump was 6.95, while the whole system was 5.54 over the measurement period. Because there was no performance data of the existing GSHP system, it was not possible to directly compare the existing control method and the outdoor air temperature method. However, it is expected that the performance of the entire system will be improved by adjusting the temperature of cold water produced by the heat pump, that is, the temperature of cold water on the load side according to the outside air temperature.

• 설비공학논문집
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• 제29권6호
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• pp.289-296
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• 2017

This study aimed to analyze the deck floor heating system of an outdoor swimming pool in terms of the thermal capacity/output and the surface temperature distribution based on the outdoor temperature, to design for anti-freezing during winter. Through the transient heat transfer simulation with PHYSIBEL and theoretical equations, the surface temperature distribution of the floor heating system at two outdoor conditions in Jeju, were calculated and evaluated. The results indicate that the specific thermal output required for maintaining $4^{\circ}C$ surface temperature at the design outdoor temperature of $0.1^{\circ}C$, was about $90W/m^2$. This performance analysis can be applied for future design criteria, including optimizations of system capacity and size.

• 설비공학논문집
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• 제13권9호
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• pp.836-844
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• 2001

For the radiant floor heating system, the possibility of suboptimal prediction control was investigated by computer simulation and experiment. For this study, TRANSYS program was used and an experimental facility consisting of two rooms (3$\times$4.4$\times$2.8m) was built. The facility enabled simultaneous comparison of two different control strategies which implemented in a separate room. Results showed that outdoor air temperature prediction control was superior to the conventional outdoor air temperature compensation control for radiant floor heating system. However, more research for fine prediction of outside air temperature was required in the future.

• KIEAE Journal
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• 제16권6호
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• pp.13-19
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• 2016

Purpose: In this study, we examined outdoor air fraction using historical data of actual Air Handling Unit (AHU) in the existing building during intermediate season and analyzed optimal outdoor air fraction by control types for economizer. Method: Control types for economizer which was used in analysis are No Economizer(NE), Differential Dry-bulb Temperature(DT), Diffrential Enthalpy(DE), Differential Dry-bulb Temperature+Differential Enthalpy(DTDE), and Differential Enthalpy+Differential Dry-bulb Temperature (DEDT). In addition, the system heating and cooling load were analyzed by calculating the outdoor air fraction through existing AHU operating method and control types for economizer. Result: Optimized outdoor air fraction through control types was the lowest in March and distribution over 50% was shown in May. In case of DE control type, outdoor air fraction was the highest of other control types and the value was average 63% in May. System heating load was shown the lowest value in NE, however, system cooling load was shown 1.7 times higher than DT control type and 5 times higher than DE control type. For system heating load, DT and DTDE is similar during intermediate season. However, system cooling load was shown 3 times higher than DE and DEDT. Accordingly, it was found as the method to save cooling energy most efficiently with DE control considering enthalpy of outdoor air and return air in intermediate season.

• 설비공학논문집
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• 제15권6호
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• pp.489-494
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• 2003

"Anmadang" of traditional Korean house is an empty space, surrounded by buildings shaped like the letter, ‘ㅁ’.‘ㅁ’shaped traditional Korean house provides much more comfortable outdoor space for various activities than ‘ㅡ’shaped traditional Korean house. In this paper it has been tried to analyse the dry bulb temperature condition of indoor and outdoor space through measurement of dry bulb temperature in Anmadang, Maru and outdoor space. This paper also analyses the correlation of dry bulb temperature between Anmadang and outdoor space with seasonal variations in traditional Korean houses.

• 설비공학논문집
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• 제11권4호
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• pp.537-541
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• 1999

The system performance of a room air conditioner using R410A was experimentally evaluated and compared with that of R22 system. The results indicated that the cooling EER(energy efficiency ratio) of R410A was 1% higher than that of R22 at the outdoor temperature of $35^{\circ}C$. As outdoor temperature increases above $35^{\circ}C$ ambient, EER of the R410A system decreased more substantially compared with R22 system. R410A showed higher compressor discharge temperature than that of R22 system at the outdoor temperature of higher than $50^{\circ}C$.