가변풍량제어시스템과 냉복도밀폐시스템의 적용에 의한 데이터센터의 냉방에너지 절감 효과 분석

박병윤,정용호 한국건축친환경설비학회 2013 한국건축친환경설비학회 논문집 Vol.7 No.2

In order to keep the data center server room temperature condition, cooling energy consumption has been rapidly increased as the increasing internal heat gain from the server devices. And the cooling units for server systems are fully operated to satisfy the indoor temperature condition, it results in the excessive energy consumption. There are many wastes of cooling energy which is caused by the structural problems in data center server room. For example, a leakage by the electric cable hole, mixing or recirculation of hot air from the hot aisle to the cold aisle, short circulation of the CRAC(Computer Room Air Conditioning),and others. So there are many strategies to reduce the waste of cooling energy in data center. In this study, cold aisle containment system and variable air volume system were proposed among the various strategies to reduce the energy cosumption. To verify the effectiveness of the energy saving system, test bed which is same with exist server room was set up in IDC(Internet Data Center) building and comparative experiments were carried out in actual conditions. As the result, in case of setting server room temperature 30℃, the server device inlet temperature exceeded 27℃ class 1 condition of the ASHRAE standard. But in case of setting server room temperature below 26℃, the range of inlet temperature of server system was 18~26℃ by cold aisle containment system. In case of variable air volume system and setting server room temperature 26℃, total energy saving was 19.8% to conventional cooling system. After all, variable air volume system and cold aisle containment system were proved to be the effective solution for energy saving cooling system.

Energy Saving Potential and Indoor Air Quality Benefits of Multiple Zone Dedicated Outdoor Air System

Lee, Soo-Jin,Jeong, Jae-Weon Council on Tall Building and Urban Habitat Korea 2019 International journal of high-rise buildings Vol.8 No.1

The purpose of this study is to evaluate the indoor air quality (IAQ) and energy benefits of a dedicated outdoor air system (DOAS) and compare them with a conventional variable air volume (VAV) system. The DOAS is a decoupled system that supplies only outdoor air, while reducing its consumption using an enthalpy wheel. The VAV system supplies air that is mixed outdoor and transferred indoor. The VAV has the issue of unbalanced ventilation in each room in multiple zones because it supplies mixing air. The DOAS does not have this problem because it supplies only outdoor air. That is, the DOAS is a 100% outdoor air system and the VAV is an air conditioning system. The transient simulations of carbon dioxide concentration and energy consumption were performed using a MATLAB program based on the thermal loads from the model predicted by the TRNSYS 18 program. The results indicated that when the air volume is large, such as in summer, the distribution of air is not appropriate in the VAV system. The DOAS however, supplies the outdoor air stably. Moreover, in terms of annual primary energy consumption, the DOAS consumed approximately 40% less energy than the VAV system.

가변풍량제어시스템과 냉복도밀폐시스템의 적용에 의한 데이터센터의 냉방에너지 절감 효과 분석

박병윤(Park Byung-Yoon),정용호(Jung Yong-Ho) 한국건축친환경설비학회 2013 한국건축친환경설비학회 논문집 Vol.7 No.3

In order to keep the data center server room temperature condition, cooling energy consumption has been rapidly increased as the increasing internal heat gain from the server devices. And the cooling units for server systems are fully operated to satisfy the indoor temperature condition, it results in the excessive energy consumption. There are many wastes of cooling energy which is caused by the structural problems in data center server room. For example, a leakage by the electric cable hole, mixing or recirculation of hot air from the hot aisle to the cold aisle, short circulation of the CRAC(Computer Room Air Conditioning), and others. So there are many strategies to reduce the waste of cooling energy in data center. In this study, cold aisle containment system and variable air volume system were proposed among the various strategies to reduce the energy cosumption. To verify the effectiveness of the energy saving system, test bed which is same with exist server room was set up in IDC(Internet Data Center) building and comparative experiments were carried out in actual conditions. As the result, in case of setting server room temperature 30℃, the server device inlet temperature exceeded 27℃ class 1 condition of the ASHRAE standard. But in case of setting server room temperature below 26℃, the range of inlet temperature of server system was 18~26℃ by cold aisle containment system. In case of variable air volume system and setting server room temperature 26℃, total energy saving was 19.8% to conventional cooling system. After all, variable air volume system and cold aisle containment system were proved to be the effective solution for energy saving cooling system.

Energy saving assessment of a desiccant-enhanced evaporative cooling system in variable air volume applications

Lee, Sung-Joon,Kim, Hui-Jeong,Dong, Hye-Won,Jeong, Jae-Weon Elsevier 2017 Applied thermal engineering Vol.117 No.-

<P><B>Abstract</B></P> <P>Desiccant-enhanced evaporative (DEVap) cooling system have been recently introduced as an alternative to conventional air conditioning systems. This system consists of a liquid desiccant dehumidifier and a dew point evaporative cooler. In this research, workable operation strategies for the DEVap system were suggested and applied to an energy simulation for estimating the energy saving potential of the system over the conventional variable air volume (VAV) system. Four different modes of operation determined according to outdoor air conditions were suggested for annual operation of the DEVap system. Energy simulations for both DEVap and VAV systems were performed for a model office building. The results showed that 2–3% of annual primary energy could be saved by using the DEVap cooling system compared with the conventional VAV system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Energy saving potential of the DEVap cooling system was evaluated. </LI> <LI> Workable modes of operation for the DEVap cooling system were suggested. </LI> <LI> The proposed system provides 2–3% annual energy saving over the conventional VAV system. </LI> <LI> The proposed system showed 10–18% primary energy saving potentials over the conventional VAV system in summer. </LI> <LI> The DEVap cooling system can be an energy conservative option for hot and humid climate zones. </LI> </UL> </P>

간접식 및 직접식 증발냉각기를 이용한 100% 외기 공조시스템의 에너지 절감효과 분석

김민휘(Kim Min-Hwi),김진효(Kim Jin-Hyo),권오현(Kwon Oh-Hyun),석윤진(Seok Yoon-Jin),정재원(Jeong Jae-Weon) 대한건축학회 2010 대한건축학회논문집 Vol.26 No.4

The main thrust of this paper is to investigate the energy saving potentials of an 100% outdoor air (OA) system integrated with indirect (IEC) and direct evaporative coolers (DEC). For estimating the energy performance of the proposed system, it was assumed that four typical 60m2 classrooms were served by two different HVAC systems; the 100% outdoor air system and the conventional variable air volume (VAV) system. Transient behavior and control characteristics of each system were modeled numerically using a commercial equation solver program. Annual air conditioning and fan energy consumptions were estimated and then the energy saving potentials of the proposed 100% OA system were predicted. It was found that 100% OA system integrated with IEC and DEC would be able to reduce the annual cooling coil load about 16-25% and the annual heating coil load around 80-87% with respect to the conventional VAV system. Consequently, the overall operating energy saving potentials of the proposed system is 21-51%, while it depends highly on the effectiveness of the IEC unit.

증발냉각 기반 전외기 공조시스템의 적정 제어 방법 및 지역별 에너지 절감효과 분석

김민휘(Kim Min-Hwi),김진효(Kim Jin-Hyo),권오현(Kwon Oh-Hyun),석윤진(Seok Yoon-Jin),정재원(Jeong Jae-Weon) 대한건축학회 2010 대한건축학회논문집 Vol.26 No.12

The purpose of this study is to investigate operable controls and energy saving potentials of an 100% outdoor air system integrated with indirect and direct evaporative coolers in eleven major cities in South Korea. It was assumed that three zones in a university campus building are served by the two different HVAC systems; a variable air volume system(VAV), and a 100% outdoor air system integrated with indirect and direct evaporative coolers. After establishing operable control strategies, energy saving potentials of each system were estimated using a simulation model representing each HVAC system. It was found that the proposed system can reduce the cooling and heating coil loads over 30% to 60% annually compared with the VAV system. It was also found that the energy saving potentials of the evaporative cooling based 100% outdoor air system is not very sensitive to the regional weather conditions.

Energy saving potential of thermoelectric radiant cooling panels with a dedicated outdoor air system

Lim, Hansol,Jeong, Jae-Weon Elsevier 2018 Energy and buildings Vol.169 No.-

<P><B>Abstract</B></P> <P>The objective of this study is to investigate the energy saving potential of a dedicated outdoor air system (DOAS) with a thermoelectric module radiant cooling panel (TEM-RCP) by comparing it with those of both a conventional variable air volume (VAV) system and a DOAS with hydraulic ceiling radiant cooling panels (CRCP) via a detailed energy simulation. The theoretical and empirical models for each component were used to estimate the energy performance of a VAV system and a DOAS with CRCP. Additionally, the TEM-RCP was analyzed by using the developed simulation models based on the semi-black box model. Hourly simulations were conducted to measure the annual energy performance. The results indicated that the DOAS with a TEM-RCP consumed 40.7% less operating energy annually when compared with that of the conventional VAV system while the proposed system exhibited only 1.0% more annual energy consumption when compared with the DOAS with hydraulic CRCP given the relatively low dimensionless figure of merit (ZT) of the TEMs (i.e., 0.73) that is used in the TEM-RCP. However, the average coefficient of performance (COP) of the TEM-RCP for cooling was 8.3, which is significantly higher than that of the conventional CRCP (4.6) during the operation period. This is because the TEM-RCP uses a cooling tower for heat removal, and its cooling water temperature is sufficiently low without requiring additional cooling of the TEM except during summer. Therefore, TEM maintains radiant panel temperature with low electric energy consumption. The study also indicated that if the ZT value of TEMs exceeded 0.75, then the proposed system exhibited lower annual energy consumption when compared to that of the DOAS with CRCP.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Water-cooled TEM-RCP was proposed for parallel cooling in DOAS. </LI> <LI> Energy saving potential of DOAS with TEM-RCP was examined. </LI> <LI> VAV system and DOAS with CRCP were compared with DOAS with TEM-RCP. </LI> <LI> DOAS with TEM-RCP showed 40.7% reduction in the annual energy compared with VAV system. </LI> <LI> TEM-RCP consumed 1.0% more annual energy than that using the CRCP in DOAS. </LI> </UL> </P>

멀티존 변풍량 터미널 유닛의 풍량 제어 방안에 관한 연구

김효준(Kim, Hyo-Jun),조영흠(Cho, Young-Hum) 한국건축친환경설비학회 2017 한국건축친환경설비학회 논문집 Vol.11 No.5

The increasing social interests for energy saving has highlighted the need for more buildings with variable air volume (VAV) systems. In order to control the VAV system at multi-zone, it is essential to control terminal unit installed in each zone. This research proposes control method with ventilation requirement of VAV terminal unit in multi-zone. And the conventional and proposed control algorithms were compared through a TRNSYS simulation program. The proposed VAV terminal unit control method satisfies all the conditions of indoor thermal comfort and indoor air quality. An energy comparison with the conventional control method showed that, the method satisfies not only the indoor thermal comfort and IAQ, but also reduces the energy consumption.

외기전담 시스템과 고성능 제습-증발냉각 시스템의 성능 비교 연구

김희정(Kim, Hui-Jeong),윤동섭(Yoon, Dong-Seob),정재원(Jeong, Jae-Weon) 대한건축학회 2015 대한건축학회 학술발표대회 논문집 Vol.2015 No.-

VAV 터미널 유닛 시스템의 데이터 기반 센서 보정 방법

김효준(Kim Hyo-Jun),조영흠(Cho Young-Hum) 한국태양에너지학회 2022 한국태양에너지학회 논문집 Vol.42 No.5

The objective of this study is to develop a data-driven prediction model and sensor calibration method in variable air volume (VAV) terminal unit systems. Based on the operational data of VAV terminal unit systems, indoor loads and carbon dioxide (CO₂) concentrations were predicted, and a Bayesian markov chain monte carlo (MCMC)-based sensor calibration method was used. The operational data of a VAV terminal unit used for data-driven model analysis and development were collected using the dynamic energy simulation tool, TRNSYS 17. Data analysis and Bayesian MCMC algorithms were analyzed and developed using R Studio. The indoor comfort and energy consumption were analyzed for the offset error effect of supply air flow rate in VAV terminal units. A sensor error distance function was developed using a prediction model. The sensor calibration method was developed using the Bayesian MCMC algorithm. The performance evaluation of sensor calibration methods utilized simulations data. It is confirmed that sensor calibration was confirmed to be possible in case of supply air flow rate sensor errors.