• 제목, 요약, 키워드: Outdoor air cooling

검색결과 202건 처리시간 0.036초

부하예측 외기냉방에 의한 건물에너지 절약에 관한 연구 (A Study on Building Energy Saving using Outdoor Air Cooling by Load Prediction)

  • 김태호;유성연;김명호
    • 설비공학논문집
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    • v.29 no.2
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    • pp.43-50
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    • 2017
  • The purpose of this study is to develop a control algorithm for outdoor air cooling based on the prediction of cooling load, and to evaluate the building energy saving using outdoor air cooling. Outdoor air conditions such as temperature, humidity, and solar insolation are predicted using forecasted information provided by the meteorological agency, and the building cooling load is predicted from the obtained outdoor air conditions and building characteristics. The air flow rate induced by outdoor air is determined by considering the predicted cooling loads. To evaluate the energy saving, the benchmark building is modeled and simulated using the TRNSYS program. Energy saving by outdoor air cooling using load prediction is found to be around 10% of the total cooling coil load in all locations of Korea. As the allowable minimum indoor temperature is decreased, the total energy saving is increased and approaches close to that of the conventional enthalpy control.

Investigation on the Reduction Effect on Cooling Power Consumption and Operating Cost of Mist-spray Outdoor Units in Air Conditioner

  • Lee, Keon-ho;Cho, Dong-woo;Kim, Hyemi;Song, Young-hak
    • Architectural research
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    • v.19 no.4
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    • pp.101-108
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    • 2017
  • The use of the air conditioner is increasing due to the rise of the outdoor temperature during summer, and the problems of the fire and the cooling performance deterioration are caused due to lack of maintenance of the outdoor unit. In particular, overall performance of cooling system and efficiency in outdoor units have been degraded due to an intake of high-temperature outdoor air thereby increasing cooling energy and operating cost. Thus, this study aimed to increase efficiency of outdoor units by evaporating and cooling intake air through mist spray at the intake port surface in the outdoor unit. The measurements results showed that total power consumption of misting outdoor unit compared to that of conventional outdoor units was reduced by 21% approximately, and total power consumption of the entire system including pump was reduced by 16.7%. In addition, the operating cost including water use was reduced by 13.5% approximately. In summary, if a mist-spray nozzle kit is installed in air-cooled outdoor units, the reduction in the usage of cooling energy and operating cost will be achieved without replacement of existing cooling systems or a large scale of repairs.

외기냉방을 이용한 냉방부하 절감 연구 (Reduction of Cooling Load using Outdoor Air Cooling)

  • 김민용;김영일;정광섭
    • 한국지열에너지학회논문집
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    • v.7 no.1
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    • pp.51-58
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    • 2011
  • Due to enhanced sealing and insulation of buildings, extensive use of glasses for building envelopes and increased use of heat generating office equipments, energy consumption of modem buildings for cooling is steadily increasing. With outdoor air cooling(ODAC) system, cooling load can be reduced by exchanging indoor air with the cold outdoor air during spring and fall seasons. If ODAC is operated based only on temperature, total cooling load may virtually increase if the outdoor humidity is high. To overcome this problem, ODAC should be controlled based on enthalpy. In this work energy saving characteristics of enthalpy controlled ODAC is studied using dynamic simulation. The result shows that cooling load can be reduced by 27% by adopting ODAC.

외기냉방 시스템의 제어방법이 에너지 소비량에 미치는 영향에 관한 연구 (Effects of Control Methods of Outdoor Air Cooling System on Energy Consumption in Building)

  • 황진원;안병천
    • 한국산학기술학회논문지
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    • v.16 no.6
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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.

외기이용 하이브리드 냉각탑 성능해석 (Numerical Analysis on the Performance of a Outdoor Air Cooled Heat exchanger for Cooling Tower)

  • 김성일;이욱현;이계중;전원표
    • 대한기계학회:학술대회논문집
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    • pp.2322-2327
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    • 2008
  • This paper is to provide analysis model that can be used to investigate the improvement in energy efficiency for cooling tower by using fresh air. Numerical analysis of Air-cooled heat exchanger for single-phase flow with variations of outdoor air temperature has been performed. A complete set of correlations of the heat transfer in both refrigerant and air sides was employed for predicting the heat transfer rate. The numerical results derived from the correlations were verified with experimental results. The energy consumption for a hybrid cooling tower has been compared for variation of a outdoor air temperature. The results showed that the hybrid cooling tower in low outdoor temperature offers a significant improvement in energy efficiency. The thermal analysis aids significantly in the solution of the design problem of hybrid cooling tower.

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Calculation of Outdoor Air Fraction through Economizer Control Types during Intermediate Season

  • Hong, Goopyo;Hong, Jun;Kim, Byungseon Sean
    • KIEAE Journal
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    • v.16 no.6
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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.

중앙 냉방시스템에 대한 외기보상제어의 절약 성능에 관한 실험적 연구 (Experimental Study on Energy Saving Performance of Outdoor Temperature Reset Control Strategy for Central Cooling System)

  • 김동철;송재엽;안병천
    • 한국지열에너지학회논문집
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    • v.7 no.2
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    • pp.30-36
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    • 2011
  • In this study, energy saving performance of outdoor temperature reset control strategy for central cooling system is researched by experiments. Outdoor temperature reset control is the control method to change indoor air set temperature according to outdoor air temperature change. The range of indoor air set temperature is represented by the comfort temperature range of indoor air temperature offered from ASHRAE and indoor air set temperature is programmed between $22^{\circ}C$ and $27^{\circ}C$ by outdoor air temperature $20^{\circ}C{\sim}32^{\circ}C$ in summer. As a result of applying outdoor temperature reset control to central cooling system, the suggested control method shows better performances of energy savings than the conventional method which indoor temperature maintains constantly.

중앙공조 및 개별공조에서의 외조기 적용 (Application of Four-season Dedicated Outdoor Air Handling Unit in Central and Personal Air-conditioning)

  • 박승태;김영일;이태호;최세영
    • 대한설비공학회:학술대회논문집
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    • pp.591-596
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    • 2008
  • The present study has been conducted to study the performance of dedicated outdoor air handling unit in central and personal air-conditioning. With conventional central and personal air-conditioning systems which are designed according to the maximum load, humidity increase above comfort level can not be avoided as the cooling load decreases. The adoption of dedicated outdoor air handling unit, however, can solve this problem. Moreover, the dedicated outdoor air handling unit has the characteristics of anti-bacteria due to dry coil, energy saving and good indoor air quality. During cooling seasons, dedicated outdoor air handling unit can save energy up to 30% than the conventional cooling+reheating system for controlling both temperature and humidity.

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외기 도입에 따른 바닥급기 시스템의 에너지 사용량 분석 (Analysis of the Energy Consumption in Underfloor Air Distribution System depending on Outdoor Air Intake Rates)

  • 김동희;허정호;조동우;유기형;유지용
    • 대한설비공학회:학술대회논문집
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    • pp.826-831
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    • 2006
  • In this paper, we discussed the energy performance of underfloor air distribution(UFAD) and overhead air distribution system according to outdoor air intake rates in a office building. For this, the laboratory(S lab.) is selected for measuring the thermal environments of UFAD system and overhead system. Based on the measured data, the TRNSYS simulation is used to evaluate the energy performance of UFAD system and the overhead system according to outdoor air intake rates. By increasing outdoor air intake rates from required outdoor air intake rates(100CMH) to maximum air intake rates, the energy savings of UFAD system comparing with overhead system are varied $15%{\sim}25.6%$ in summer, $12.8%{\sim}19%$ in fall/spring and not varied in winter(8%). As results of simulations on stratification height and cooling set temperature, the lower the stratification height and the higher cooling set temperature, the larger cooling energy savings of UFAD comparing with overhead system according to outdoor air intake rates.

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외기 전용 공조기의 동특성 시뮬레이션 (Dynamic Simulation of a Dedicated Outdoor Air-conditioning System)

  • 김정민;김영일;정광섭;박승태
    • 대한설비공학회:학술대회논문집
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    • pp.322-327
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    • 2007
  • Dedicated outdoor air-conditioning(DOA) system that utilizes pre-cooling and desiccant dehumidification can be superior to conventional cooling and reheating system with respect to energy consumption and indoor thermal comfort. In this work, simulation has been conducted to study various factors that affect the performance of DOA. Dynamic simulation shows the transient variation of temperature and humidity as the on/off control logic is imposed. Exit humidity of process air and flow rate are varied to study the effect on exit temperature of process air, dehumidification quantity, required regeneration temperature and exit humidity of regeneration air. For an outdoor air condition of $28.5^{\circ}C$ temperature, 16 g/kg humidity ratio and 2000 cmh flow rate, the dehumidification efficiency is increased by 4.6% as the flow rate is doubled.

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