• Title/Summary/Keyword: Night purge

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Night Purge Control Strategies With Outdoor Air Temperature Conditions for Central Cooling System (중앙냉방시스템의 외기온도조건을 고려한 나이트 퍼지 제어방안에 관한 연구)

  • Hwang, Jin-Won;Ahn, Byung-Cheon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.10
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    • pp.6759-6765
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    • 2015
  • In this study, the effects of control strategies of night-purge control system on control characteristics and energy consumption for central cooling system in building are researched by simulation. The start time and set-point temperature for night-purge control with outdoor temperature changes and building cold storage performance are obtained. The system analysis modelling is done by using TRNSYS program package, and the control performances with suggested night-purge control method are compared with the existing control ones. As a result, the suggested night-purge control method shows maximum 16.8% and 28.6% energy saving in comparison with existing control method and conventional one without night-purge control, respectively.

Energy Saving Effect of the Night Purge Control using ERV in a School Building (전열교환형 환기시스템을 이용한 학교건물의 나이트 퍼지 적용 효과 분석)

  • Kim, Su-Yeon;Won, Jung-kwan;Kim, Jae-Hyung;Song, Doo-Sam
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.28 no.11
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    • pp.421-427
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    • 2016
  • The indoor temperature of a building increases during the day due to solar radiation. This behavior is significant in school buildings that are finished with high thermal capacity materials. Moreover, in school buildings, windows cannot be opened until the class has finished owing to the security policy of schools. Consequently, classrooms maintain a high temperature throughout the morning. It is thus important to remove the indoor heat before the commencement of classes in order to reduce the cooling energy needed. The Energy Recovery Ventilator (ERV) system is currently being installed in school buildings for ventilating the classrooms. Night-purge control using ERV can be a good strategy to cool the classroom in advance of the operation of the cooling system. However, the optimal operation method of the ERV for night-purge control has not yet been reported. In this study, the effect of night-purge control with ERV in school buildings is analyzed by simulation method. The results of this study showed that the energy saving effect of night-purge control with ERV is most effective in the case of 2 hours operation prior to the commencement of the first lass and when enthalpy based outdoor air cooling is used.

Night Purge Evaluation Using the RTS-SAREK in Office Buildings (RTS-SAREK을 이용한 사무용 건물의 나이트 퍼지 성능 평가)

  • Shin, Dongshin;Park, Sungkeun;Park, Youngsoo;Park, Jisu;Lee, Jinyoung
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.27 no.12
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    • pp.633-638
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    • 2015
  • This study evaluates the capacity of night purging in office buildings to reduce the cooling load. RTS-SAREK is used to estimate the performance of night purging on the steady state. To overcome steady state RTS program limitations, we added unsteady heat transfer equations. When the ACH (Air Change per Hour) increases, the wall temperature decreases in both the steady and unsteady states. The unsteady heat transfer rate is different from the steady transfer rate, which validates the unsteady calculation. When ACH is low, the heat transfer rate increases continuously with time. When ACH becomes higher, the heat transfer rate increases and decreases with time. When ACH is quite high, there exists a large difference in the heat transfer rate between the steady and unsteady calculations, which emphasizes the importance of the unsteady calculation.

A Study on Energy Saving Performance by Night Purge Cooling with Pressurized Under Floor Air Distribution System (가압식 바닥공조 시스템과 야간 외기냉방의 병용에 따른 에너지저감 성능에 관한 연구)

  • Yoon, Seong-Hoon
    • Journal of the Korean Solar Energy Society
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    • v.40 no.1
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    • pp.25-33
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    • 2020
  • It has been reported about the energy saving performance of UFAD(under floor air distribution) system and NPC(night purge cooling) system respectively which are applied for commercial buildings. However, when two systems are used at the same time, the effect of heat transfer from floor plenum to slab may vary depending on the operating conditions of NPC. In this study, cooling energy demands were analyzed for building models with UFAD and NPC by using TRNSYS 17 program. UFAD was applied as a cooling system of the base building model, and the cooling energy demands were compared for 64 cases in which the operating time, supply airflow rate, and outdoor air temperature(To) of NPC. As a result, it was confirmed that the cooling energy demands were reduced to 30 ~ 80% level compared to UFAD alone, and in particular, the energy demand was reduced in proportion to the supply airflow rate or the operating time while To was 16 ~ 20℃. However, when To was 22℃, the increase in the supply airflow rate or the operating time results in a disadvantage in terms of cooling energy demands. In addition, the cooling energy demands for UFAD+NPC model were analyzed by applying weather data from three regions with different average outdoor air temperatures. As a result, the cooling energy demand of operating NPC only when To was below 20℃ was reduced by 27% compared to that of operating NPC continuously for 8 hours.

A Study on the Effective Adjustment of Building Insulation Performance and the Application of the Night Purge Ventilation System for Low Energy Building Design (저에너지건축물 설계를 위한 건축물 단열성능의 효과적 조정과 야간외기 도입에 따른 에너지 시뮬레이션 연구)

  • Yun, Hyun-Su;Lee, Tae-Kyu;Kim, Jeong-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.10
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    • pp.625-632
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    • 2018
  • This study was done to reduce total energy demand based on resource shortage problems and to provide improvement points for more efficient adjustment of the high insulation standards for saving energy in Korea. The demand sensitivity was fully considered by varying the slope of each building. The energy performance of the building was maximized by the introduction of outdoor air at night. A final low-energy building model was developed with the two measures combined, and the short-term operation of the night-fuzzy ventilation system was simulated. The result showed a reduction of about 6 to 7 percent compared to the base model. The results could have many implications in terms of the need to conduct demand sensitivity analyses in architectural design.

Study on the Subway Platform Thermal Environment for using Natural Energy (자연에너지 활용을 위한 지하철 승강장 열환경에 관한 연구)

  • KIM, Hoe-Ryul;KIM, Dong-Gyu;KUM, Jong-Soo;CHUNG, Yong-Hyun;PARK, Sung-Chul
    • Journal of Fisheries and Marine Sciences Education
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    • v.21 no.2
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    • pp.269-277
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    • 2009
  • Ventilation equipment performs a central role to maintain comfort subway environment. So ventilation equipment of Busan subway line No.1 is required to improve thermal environment. In this study, conditions of thermal environment are presented to improve ventilation equipment at existing subway station platforms by measuring thermal environment of platforms operated ventilation equipment at 14 stations of Busan subway line No.1. AWS of data in comparison with the neighbouring platforms and thermal environment analysis. Thermal environment status of subway platform analysis results are as follows. 1)Daytime platform temperature was higher than outdoor temperature, but night time platform temperature was lower than outdoor temperature. 2)Train wind had effect on improving thermal comfort in platform. 3)When outdoor temperature is below $24^{\circ}C$, inlet air is able to lower than platform temperature. 4)Considering existing ventilation system, night purge systems is useful to improving platform thermal environment.

The study for thermal environment improvement at subway station platform (Part 2: Thermal environment according to supply outdoor temperature) (지하역사 승강장 열환경 개선을 위한 연구 (제2보: 도입외기온도에 따른 승강장 열환경))

  • Kim, Hoe-Ryul;Kim, Dong-Gyu;Kum, Jong-Soo;Chung, Yong-Hyun;Kim, Jong-Ryel;Kim, Min-Soo
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.561-564
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    • 2009
  • This study is to examine the possibility of pre-cooling at platform. Through measurement of the thermal environment of Bujeon Subway platforms, review the potential use of ground-water and night purge. The results of this research can improve the thermal environment pre-cooling of the design.

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Experimental Study of Cooling Energy Saving Verification Using Blinds and Phase Change Material(PCM) (창호 블라인드와 상변화물질 적용에 의한 냉방 에너지 사용량 절감효과에 대한 검토 연구)

  • Song, Young-Hak;Kim, Ki-Tae;Koo, Bo-Kyung;Lee, Keon-Ho
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.1
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    • pp.26-31
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    • 2014
  • This study looks into changing building energy use by application of phase change material (PCM). PCM does not need extra energy for operation and is used for reducing building energy use and, CO2 output by displaying semi-permanent effects after installation. It also is able to avoid the maximum electric power time-zone by inducing a time lag phenomenon of cooling and heating loads with high thermal capacity using latent heat. To verify the efficiency of blinds and PCM, tests about the PCM operation mechanism using air conditioning machinery and nocturnal panel cooling were done. In the test results of the case using PCM installation, a $45^{\circ}$ blind angle with machinery air conditioning and nocturnal panel cooling at the same time shows a 22 percent energy saving effect against general space. The test results of each case were compared and analyzed based on the blind and window opening settings. Finally, the energy reduction of existing buildings using PCM application was reviewed based on the final measurement results.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2016 (설비공학 분야의 최근 연구 동향 : 2016년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.6
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    • pp.327-340
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    • 2017
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2016. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of flow, heat and mass transfer, the reduction of pollutant exhaust gas, cooling and heating, the renewable energy system and the flow around buildings. CFD schemes were used more for all research areas. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results of the long-term performance variation of the plate-type enthalpy exchange element made of paper, design optimization of an extruded-type cooling structure for reducing the weight of LED street lights, and hot plate welding of thermoplastic elastomer packing. In the area of pool boiling and condensing, the heat transfer characteristics of a finned-tube heat exchanger in a PCM (phase change material) thermal energy storage system, influence of flow boiling heat transfer on fouling phenomenon in nanofluids, and PCM at the simultaneous charging and discharging condition were studied. In the area of industrial heat exchangers, one-dimensional flow network model and porous-media model, and R245fa in a plate-shell heat exchanger were studied. (3) Various studies were published in the categories of refrigeration cycle, alternative refrigeration/energy system, system control. In the refrigeration cycle category, subjects include mobile cold storage heat exchanger, compressor reliability, indirect refrigeration system with $CO_2$ as secondary fluid, heat pump for fuel-cell vehicle, heat recovery from hybrid drier and heat exchangers with two-port and flat tubes. In the alternative refrigeration/energy system category, subjects include membrane module for dehumidification refrigeration, desiccant-assisted low-temperature drying, regenerative evaporative cooler and ejector-assisted multi-stage evaporation. In the system control category, subjects include multi-refrigeration system control, emergency cooling of data center and variable-speed compressor control. (4) In building mechanical system research fields, fifteenth studies were reported for achieving effective design of the mechanical systems, and also for maximizing the energy efficiency of buildings. The topics of the studies included energy performance, HVAC system, ventilation, renewable energies, etc. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which could be help for improving the energy efficiency of the buildings. (5) The field of architectural environment was mostly focused on indoor environment and building energy. The main researches of indoor environment were related to the analyses of indoor thermal environments controlled by portable cooler, the effects of outdoor wind pressure in airflow at high-rise buildings, window air tightness related to the filling piece shapes, stack effect in core type's office building and the development of a movable drawer-type light shelf with adjustable depth of the reflector. The subjects of building energy were worked on the energy consumption analysis in office building, the prediction of exit air temperature of horizontal geothermal heat exchanger, LS-SVM based modeling of hot water supply load for district heating system, the energy saving effect of ERV system using night purge control method and the effect of strengthened insulation level to the building heating and cooling load.