• Title/Summary/Keyword: Outdoor air conditioning load

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A Study on the Estimation of Temperature, Humidity and Cooling Load (온도, 습도 및 냉방부하 예측에 관한 연구)

  • Yoo, Seong-Yeon;Han, Seung-Ho;Lee, Je-Myo;Han, Kyou-Hyun;Noh, Kwan-Jong
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.80-85
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    • 2006
  • The peak demand of electricity in summer season mainly comes from the day time cooling loads. Ice thermal Storage System (ITSS) uses off-peak electricity at night time to make ice for the day time cooling. In order to maximize the use of cold storage in ITSS, the estimation of day time cooling load for the building is necessary. In this study, we present a method of cooling load estimation using 5 years of normalized outdoor temperature, relative humidity, and the building construction data. We applied the hourly-based estimation to a general hospital building with relatively less sudden heat exchange and the results are compared with the measured cooling load of the building. The results show that the cooling loads estimation depends on the indoor cooling design temperature of the building.

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Experimental Study on the Performance Improvement of a Simultaneous Heating and Cooling Heat Pump in the Cooling-main Operating Mode (냉방주체 운전모드에서 동시냉난방 열펌프 성능향상에 관한 실험적 연구)

  • Chung, Hyun-Joon;Joo, Young-Ju;Kang, Hoon;Kim, Yong-Chan;Choi, Jong-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.5
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    • pp.314-320
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    • 2008
  • The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the improved wall insulation. Hence, a multi~heat pump is required to cover heating and cooling simultaneously for each indoor unit. In this study, the operating characteristics and performance of a simultaneous heating and cooling heat pump in the cooling-main operating mode were investigated experimentally. The system adopted a variable speed compressor using R410A with four indoor units and one outdoor unit. In the cooling-main mode, the heating capacity decreased due to reduction of flow rate to the indoor unit under heating mode operation. The EEV opening was adjusted to increase flow rate to the indoor unit under heating mode operation. The total capacity and COP in the cooling-main mode increased by 20.5% and 29.2%, respectively, compared with those in the cooling-only mode.

Cooling Performance of a Hybrid Refrigeration System for Telecommunication Equipment (통신기기 냉각용 하이브리드 냉방시스템의 성능특성)

  • Jeon, Jong-Ug;Kim, Yong-Chan;Choi, Jong-Min
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.489-494
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    • 2006
  • Electronic and telecommunication industries are constantly trying to develop compact components having high power density. Therefore, a proper heat dissipation method is very important to allow reliable operation of the telecommunication equipment. In this study, a hybrid refrigeration system for a telecommunication equipment room was designed to save energy consumption and improve reliability of the compressor In addition, the performance of the hybrid refrigeration system was measured with a variation of outdoor load. The designed hybrid refrigeration system for the telecommunication equipment shelter saved the energy approximately 50%e at the mode switch temperature of $8.3^{\circ}C$.

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Cooling and Heating Performance Under the Actual Operating Condition of a Ground Source Heat Pump System in a School Building (학교 건물에 설치된 지열원 열펌프 시스템의 실사용을 통한 냉난방성능 연구)

  • Kim, Eui-Young;Jeong, Young-Man;Song, Jae-Do;Lee, Jae-Keun;Kim, In-Kyu;Lee, Dong-Hyuk
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.586-589
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    • 2009
  • This paper presents the performance of a water-to-refrigerant type ground source heat pump (GSHP) system installed in a school building in Korea. For analyzing the performance of the GSHP system, we monitored various operating conditions, including the outdoor temperature, the ground temperature, and the input power of the GSHP system. The average cooling coefficient of performance (COP) of the heat pump was found to be 8.5 at 60% partial load condition, while the overall system COP was found to be 5.9. The average heating COP of the heat pump was found to be 6.5 at 45% partial load condition, while the overall system COP was found to be 5.0.

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A Study on the Method of Estimating Optimum Supply Water Temperature Considering the Heating Load and the Heat Emission Performance of Radiant Floor Heating Panel (난방부하와 온수온돌의 방열성능을 고려한 적정 공급온수온도 산출방법에 관한 연구)

  • Choi, Jeong-Min;Lee, Kyu-Nam;Ryu, Seong-Ryong;Kim, Yong-Yee;Yeo, Myoung-Souk;Kim, Kwang-Woo
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.795-800
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    • 2006
  • A common approach to achieve better thermal comfort with hydronic radiant floor heating system is supply water temperature control. This is the control method through which supply water temperature is varied with outdoor temperature. In this study, a comprehensive, yet simple calculation method to find optimum supply water temperature is evaluated by combining heat loss from the building and heat emission from the hydronic radiant floor heating system. And then the control performance of suggested calculation method is confirmed through experiment. It is shown that indoor air temperature is stably maintained around the set point.

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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.

Experimental Study on the Performance Improvement of a Simultaneous Heating and Cooling Heat Pump in the Heating-main Operating Mode (난방주체 운전모드에서의 동시냉난방 열펌프 성능향상에 관한 실험적 연구)

  • Kang, Hoon;Jung, Hyen-Joon;Joo, Young-Ju;Kim, Yong-Chan;Choi, Jong-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.4
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    • pp.245-251
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    • 2008
  • The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. Hence, the development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the operating characteristics and performance of a simultaneous heating and cooling heat pump in the heating-main operating mode were investigated experimentally. The system adopted a variable speed compressor with four indoor units and one outdoor unit with R-410A. In the heating-main mode, the cooling capacity was lower than the design cooling capacity due to the reduction of the flow rate in the indoor unit for the cooling, with the increase of the heating capacity. To solve these problems, the performance characteristics of the simultaneous heating and cooling heat pump in the heating-main mode were investigated by varying the flow rate to the indoor unit for the cooling and the compressor rotating speed. In addition, the adequate control methods were suggested to improve the system efficiency.

The Performance of a Simultaneous Heat and Cooling Heat Pump at Various Charging Conditions (동시냉난방 히트펌프의 냉매 충전량과 운전모드 변화에 따른 성능특성에 관한 연구)

  • Song, In-Sik;Choi, Jong-Min;Joo, Young-Ju;Chung, Hyun-Joon;Kang, Hoon;Kim, Yong-Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.7
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    • pp.492-499
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    • 2008
  • The cooling load in winter is significant in many commercial buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. The development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the performance of a multi-heat pump with 3-piping system was investigated as a function of refrigerant charge and its performance was analyzed in cooling mode, heating mode, and heat recovery mode. COP in the heating or cooling mode showed little dependence on refrigerant charge at overcharge conditions, while those were strongly dependent on refrigerant charge at undercharge conditions and outdoor inlet temperature. In the heat recovery mode, the performance of the system was very sensitive to charge amount at all conditions. Optimum charge amount in the heat recovery mode was 14% lower than that in the cooling mode at the standard condition because the refrigerant only passed the indoor units. It is required to store the excessive refrigerant charge in a storage tank to optimize the system performance at operating modes.

Heating Performance of a Ground Source Heat Pump System through Actual Operation (지열원 히트펌프시스템의 실사용을 통한 난방성능연구)

  • Koo, Kyoung-Min;Jeong, Young-Man;Hwang, Yu-Jin;Lee, Jae-Keun;Jang, Se-Yong;Kim, In-Kyu;Jin, Sim-Won;Lee, Dong-Hyuk
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.1341-1346
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    • 2008
  • This paper presents the heating performance of a water-to-refrigerant type ground source heat pump system (GSHP) installed in a school building. The evaluation of the heating performance has been conducted under the actual operating conditions of GSHP system in the winter. Ten units with the capacity of 10 HP each were installed in the building. Also, a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth was constructed for the GSHP system. For analyzing the heating performance of the GSHP system, we monitored various operating conditions, including the outdoor temperature, the ground temperature, and the water temperature of inlet and outlet of the ground heat exchanger. Simultaneously, the heating capacity and the input power were evaluated for determining the heating performance of the GSHP system. The average heating coefficient of performance (COP) of the heat pump was found to be 5.1 at partial load of 46.9%, while the overall system COP was found to be 4.2.

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Heating Performance of a Ground Source Heat Pump System through Actual Operation (지열원 히트펌프시스템의 실사용을 통한 난방성능연구)

  • Koo, Kyoung-Min;Jeong, Young-Man;Hwang, Yu-Jin;Lee, Jae-Keun;Jang, Se-Yong;Kim, In-Kyu;Jin, Sim-Won;Lee, Dong-Hyuk
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.788-793
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    • 2008
  • This paper presents the heating performance of a water-to-refrigerant type ground source heat pump system (GSHP) installed in a school building. The evaluation of the heating performance has been conducted under the actual operating conditions of GSHP system in the winter. Ten units with the capacity of 10 HP each were installed in the building. Also, a closed vertical typed-ground heat exchanger with 24 boreholes of 175 m in depth was constructed for the GSHP system. For analyzing the heating performance of the GSHP system, we monitored various operating conditions, including the outdoor temperature, the ground temperature, and the water temperature of inlet and outlet of the ground heat exchanger. Simultaneously, the heating capacity and the input power were evaluated for determining the heating performance of the GSHP system. The average heating coefficient of performance (COP) of the heat pump was found to be 5.1 at partial load of 46.9%, while the overall system COP was found to be 4.2.

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