• Title, Summary, Keyword: Outdoor air cooling

Search Result 202, Processing Time 0.033 seconds

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
    • /
    • v.40 no.1
    • /
    • pp.25-33
    • /
    • 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.

Indoor and Outdoor Distribution of Legionella spp and Microbes on Cooling Towers Water of Central Air Conditioning Facilites (중앙집중식 냉방시설의 냉각탑수중 레지오넬라균과 실내외 미생물 분포에 관한 연구)

  • 방선재;이철민;김윤신;선우영
    • Journal of Environmental Health Sciences
    • /
    • v.28 no.3
    • /
    • pp.39-48
    • /
    • 2002
  • Cooling towers water has frequently been known as a source of infection in outbreaks of Legionnaires' disease and a source of indoor air pollution. However, there have been a few reports on the presence of Legionella in cooling towers water and aerosols of various public facilities. This study was carried out to investigate the indoor and outdoor dis-tribution of Legionella spp and microbe from 132 cooling towers water of public facilities detected 1. pneumophila in Seoul and Gyeonggi-Do areas. The results showed that the Lpneumophila among the selected 132 cooling towers was detected mostly in July (12.0%), followed by August (4.0%) and June, September no-detected. The 1. pneumophiia in public facilities was detected mostly in department store (27.3%), followed by hospital (8.7%), office building (5.9%), big market (5.0%) and hotel, subway no-detected. The pH values of cooling towers water with presence of 1. pneumophila showed mostly 8.0 or higher (9.5%), followed by 7.0~8.0 (6.8%), lower 7.0 no-detected. The tem-perature of cooling towers water with presence of L pnemophila showed mostly 30℃ or higher (9.8%), followed by 26~30℃ (6.9%), lower 25℃ no-detected. The turbidity of cooling towers water with presence of 1. pneumaphila showed mostly 1-2 M (8.8%), followed by above 2 NTU (5.9%), lower 1 NTU no-detected. The correlation coef-ficient between indoor and outdoor concentration of microbes in public facilities showed 0.67 in Legionella spy. (p>0.05), 0.93 in bacteria (p<0.01), 0.94 in fungus (p<0.01), 0.98 in coilform (p<0.01), respectively.

A Study on the Regional Energy Conservation Effects of a Multi-stage Outdoor Air Enabled Cooling System in a Data Center (데이터센터용 멀티 외기이용 냉방시스템의 지역별 에너지 절감효과에 대한 연구)

  • Park, Moon-Ki;Chang, Hyun-Jae
    • Journal of the Korean Solar Energy Society
    • /
    • v.37 no.1
    • /
    • pp.71-80
    • /
    • 2017
  • A Data center houses a large number of server computers, storage and etc in racks. With the rapid increase of heat generation rates per rack in a data center, energy consumption rates for cooling have been increased year by year. In this study, energy conservation effects of a MOA (multi-stage outdoor air enabled) cooling system in a data center has been investigated when it is applied to 5 different locations, Korea. As results, Energy conservation effects of the MOA cooling system was achieved at about 20% to 30%. Humidifier operation time was 40 to 55 days when supply air temperature was maintained at 13, and humidity condition was kept within the allowed range even though humidifier was off. Furthermore, humidification was not needed when supply air temperature was maintained at $25^{\circ}C$. In selected 5 locations in Korea, the difference of regional climatic conditions affected no more than 5% in cooling energy consumption rates.

The performance evaluation of outdoor unit cooling system in a residential apartment complex (주상복합의 실외기 형태에 따른 냉방시스템 성능 평가)

  • Kyung, Seo-Kyung;Kim, Yun-Jin;Lim, Jung-Hee;Kim, Byung-Seon
    • 한국태양에너지학회:학술대회논문집
    • /
    • /
    • pp.263-268
    • /
    • 2008
  • In a residential complex case, the efficiency of land use are maximized, but a variation of external condition such as load in-equality, the increase in wind velocity and solar radiation by a height causes increasing energy in a building. Besides, because of increasing window size for a lighting and a view, it comes heating load in winter and cooling load in summer. A choice of cooling-system is important for this reason. Recently an internal high-rise residential complex installs an air-cooling system and operates individual heating. However, this study applies water-cooling used one public cooling-tower instead of an air-cooling system, also with an efficiency test of an air and a water-cooling system, consider an internal applicability.

  • PDF

A Study on the Performance Improvement of a Simultaneous Heating and Cooling Water Source Heat Pump System by Controlling of the Refrigerant Flow Rate in an Outdoor Unit (수열원 냉난방 동시형 히트펌프 시스템의 실외 열교환기 유량제어를 통한 성능개선에 관한 연구)

  • Bae, Heung Hee;Lee, Dong Hyuk;Lee, Sanghun;Kim, Byengsoon;Ahn, Young Chull
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.25 no.3
    • /
    • pp.131-136
    • /
    • 2013
  • The present study has conducted cycle design and control technology of a water source VRF heat pump system. Previously, study of a simultaneous heating and cooling in an air source VRF heat pump system has been conducted. However, performance data and design methods for simultaneous heating and cooling in a water source VRF heat pump system are limited in the literature, due to various system parameters and operating conditions. In this study, the operating characteristics and performances of a simultaneous heating and cooling heat pump system are carried out, in simultaneous operation modes. Control logics of an EEV are developed for flow rate control to the outdoor unit, and are verified. When the control logics are applied, the simultaneous cooling and heating performances are sufficiently achieved, and system COPs are increased by up to 23.4%.

Performance Characteristics of a Hybrid Air-Conditioner for Telecommunication Equipment Rooms (통신기지국용 하이브리드 냉방기의 성능특성 연구)

  • Kim, Yong-Chan;Choi, Jong-Min;Kang, Hoon;Yoon, Joon-Sang;Kim, Young-Bae;Choi, Kwang-Min;Lee, Ho-Seong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.18 no.11
    • /
    • pp.874-880
    • /
    • 2006
  • The power density and heat dissipation rate per unit area of the telecommunication equipment have been increased with the technology development in the footprint of telecommunication hardware. A proper heat dissipation method from the PCB module is very important to allow reliable operation of its electronic component. In this study, a hybrid air-conditioner for the telecommunication equipment room was designed to save energy and obtain system reliability. For high outdoor temperatures, the hybrid system operates in the vapor compression cycle, while, for low outdoor temperatures, the hybrid system works in the secondary fluid cooling cycle with no operation of the compressor. The performance of the hybrid air-conditioner was measured by varying outdoor and indoor temperatures. The hybrid air-conditioner yielded 50% energy saving compared with the conventional refrigeration system when the mode switch temperature was $8.3^{\circ}C$.

Evaluation of the operating reliability on the concurrent heating-cooling system air conditioner with high-head and long-line conditions (동시냉난방 시스템 에어컨의 고낙차 장배관 운전 신뢰성 평가)

  • Kim, Tae-An;Lee, Seung-Chan;Tae, Sang-Jin;Jung, Gyoo-Ha;Moon, Je-Myung;Kim, Youn-Jea
    • Proceedings of the SAREK Conference
    • /
    • /
    • pp.609-614
    • /
    • 2008
  • The heating and cooling performance of system multi-air conditioner under high-head and long-line conditions are experimentally investigated. The maximum head and tube length were 110 m and 1000 m, respectively. The experimental system was composed of 4 outdoor units with module systems, and 13 indoor units which were joined with the mode change unit by single-tube circuit. Field tests without indoor and outdoor temperature control were performed in a general office building with 22 different working conditions. Experimental results were prepared on the p-h diagram. Also the oil level in the compressor was normally maintained at the safety zone for the system multi-air conditioner with high-head and long-line conditions.

  • PDF

Performance Evaluation of Heat Exchangers due to Air-side Particulate Fouling in the Air Conditioners (공기측 파울링에 의한 에어컨 열교환기의 성능분석 연구)

  • 안영철;조재민;이재근;이현욱;안승표;윤덕현;하삼철;강태욱
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.15 no.6
    • /
    • pp.447-453
    • /
    • 2003
  • The air-side particulate fouling in the heat exchangers of HVAC applications degrades the performance of cooling capacity, pressure drop across a heat exchanger, and indoor air quality. Indoor and outdoor air contaminants foul heat exchangers. The purpose of this study is to investigate the cooling performance and pressure drop on the air-side particulate fouling of heat exchangers for air conditioners. Air conditioners being used in the field such as inn, restaurant, and office are collected in chronological used order. Test results show 15% decrease of the cooling capacity and 44% increase of the pressure drop for the 7 years air conditioners used in the seaside inn.

Comparison of Performance Variation between R-22 and R-410A Refrigeration Systems (운전조건 변화에 따른 R-22 냉동사이클과 R-410A 냉동사이클의 성능변화 비교)

  • 박태준;이민규;정지환;장근선
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.15 no.3
    • /
    • pp.166-176
    • /
    • 2003
  • Experiments have been conducted in order to make comparisons of a alternative refrigerant (R-410A) cycle characteristic with an existing refrigerant (R-22) cycle characteristic in terms of cooling capacity and coefficient of performance (COP). The parameters examined in the present work include air flow rate, indoor/outdoor air temperatures, and indoor relative humidity. These two refrigeration cycles share all components except compressor, accumulator, oil separator, and piping connecting them. The measurements were made using an air-enthalpy calorimeter. The experimental results show that the R-410A cycle has many advantages over indoor conditions while the R-22 cycle has better performance over outdoor conditions.

Energy Saving Potentials of Dedicated Outdoor Air System in a High-rise Apartment Building (외기전담 시스템 기반 초고층 공동주택 중앙 환기시스템의 에너지 절감효과 분석)

  • Kim, Min-Hwi;Kim, Jin-Hyo;Kwon, Oh-Hyun;Jeong, Jae-Weon
    • 한국태양에너지학회:학술대회논문집
    • /
    • /
    • pp.291-296
    • /
    • 2009
  • This paper investigates the energy saving potentials of a dedicated outdoor air system (DOAS) applied to a highrise apartment building. As for a typical $132-m^2$ apartment unit, two different HVAC systems; centralized DOAS-Ceiling Radiant Cooling Panel and decentralized Energy Recovery Ventilator-Packaged Air Conditioner were installed. Transient behavior and control characteristics of each system were modeled numerically using a commercial equation solver program, and annual cooling coil load and heating load reduction potentials were compared. The research shows that DOAS-Ceiling Radiant Cooling Panel system can reduce the cooling coil load over 21% annually compared with the current Energy Recovery Ventilator-Packaged Air Conditioner pair. In addition, over 40% of annual ventilation heating load can be reduced by use of DOAS.

  • PDF