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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 2014 (설비공학 분야의 최근 연구 동향: 2014년 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.27 no.7
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    • pp.380-394
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    • 2015
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2014. 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 heat and mass transfer, cooling and heating, and air-conditioning, the flow inside building rooms, and smoke control on fire. Research issues dealing with duct and pipe were reduced, but flows inside building rooms, and smoke controls were newly added in thermal and fluid engineering research area. (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 for thermal contact resistance measurement of metal interface, a fan coil with an oval-type heat exchanger, fouling characteristics of plate heat exchangers, effect of rib pitch in a two wall divergent channel, semi-empirical analysis in vertical mesoscale tubes, an integrated drying machine, microscale surface wrinkles, brazed plate heat exchangers, numerical analysis in printed circuit heat exchanger. In the area of pool boiling and condensing, non-uniform air flow, PCM applied thermal storage wall system, a new wavy cylindrical shape capsule, and HFC32/HFC152a mixtures on enhanced tubes, were actively studied. In the area of industrial heat exchangers, researches on solar water storage tank, effective design on the inserting part of refrigerator door gasket, impact of different boundary conditions in generating g-function, various construction of SCW type ground heat exchanger and a heat pump for closed cooling water heat recovery were performed. (3) In the field of refrigeration, various studies were carried out in the categories of refrigeration cycle, alternative refrigeration and modelling and controls including energy recoveries from industrial boilers and vehicles, improvement of dehumidification systems, novel defrost systems, fault diagnosis and optimum controls for heat pump systems. It is particularly notable that a substantial number of studies were dedicated for the development of air-conditioning and power recovery systems for electric vehicles in this year. (4) In building mechanical system research fields, seventeen 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, and renewable energies, piping in the buildings. Proposed designs, performance performance tests using numerical methods and experiments provide useful information and key data which can improve 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 evaluation of work noise in tunnel construction and the simulation and development of a light-shelf system. The subjects of building energy were worked on the energy saving of office building applied with window blind and phase change material(PCM), a method of existing building energy simulation using energy audit data, the estimation of thermal consumption unit of apartment building and its case studies, dynamic window performance, a writing method of energy consumption report and energy estimation of apartment building using district heating system. The remained studies were related to the improvement of architectural engineering education system for plant engineering industry, estimating cooling and heating degree days for variable base temperature, a prediction method of underground temperature, the comfort control algorithm of car air conditioner, the smoke control performance evaluation of high-rise building, evaluation of thermal energy systems of bio safety laboratory and a development of measuring device of solar heat gain coefficient of fenestration system.

Study and Survey of Operating Efficiency with Cool Storage System (빙축열냉방시스템의 운전효율에 관한 조사연구)

  • 손학식;심창호;김강현;김재철
    • Journal of Energy Engineering
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    • v.11 no.1
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    • pp.1-9
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    • 2002
  • The purpose of this study is to maintain high efficiency and reasonable use of cool thermal storage systems operated in the domestic building sector. As the result of efficiency test from the five types of operated cool storage systems on the condition that COP ranges are 2.6 to 3.4 during the day time and 2.1 to 3.0 during the night time and it decreased by more than 30% of rated COP given 3.8 to 3.0. The Analysis of cool storage rate shows that only 3 (21.4%) systems out of 15 buildings hold to over 40% capacity for its total capacity. To prevent the decrease in operating efficiency, it should correct the malfunction of 3-way valve and expansion valve and the mistake of control values for schedule program and increase cooling tower capacity. In order to improve piping line, it needs bypass brine line off refrigerator, separation of chilled water line with Ice Slurry system at day and night time and speed control of chilled and warm water pumps. This study does require the more studies on improving difficulty of increasing cooling load with Ice on Coil system, waterproofing with Ice Ball system, COP drop during the night time with Ice Lens, low operating temperature during the day time with Ice Slurry and increasing of Power loss due to hot gas de-icing with Ice Harvest in the future.

Determination of Design Basis for a Storage System for Spent Fuel in Korea (국내 사용후핵연료 저장시스템의 설계기준 설정 인자 고찰)

  • Yoon, Jeong-Hyoun;Lee, Eun-Yong;Woo, Sang-In;Kim, Tae-Man
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.9 no.2
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    • pp.113-119
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    • 2011
  • Safe operation and maintenance of engineered dry storage systems for spent fuel from nuclear power plants basically depends on adequately adopted design requirements. The most important design target of the system are those which provide the necessary assurances that spent fuel can be received, handled, stored and retrieved without undue risk to health and safety of workers and the public. To achieve these objectives, the design of the system incorporates features to remove spent fuel residual heat, to provide for radiation protection, and to maintain containment over the lifespan of the system as specified in the design specifications. The features also provide for all possible anticipated operational occurrences and design basis events in accordance with the design basis as guided by the designated regulations. The general performance requirements of a projected storage system are introduced in this paper. The storage system is designed to store fuel assemblies in associated with designated regulatory requirements. Small increases/decreases in maximum burnup can be adjusted with cooling time. These variations are compensated for by a corresponding small site-specific increase/decrease in the design basis-cooling period, as long as the maximum heat load and radioactivity of loaded fuel assemblies are met. Generic design basis events considered for the storage system are summarized. Shielding and radiological requirements along with mechanical and structural are derived in this study.

An Experimental Study on the Effect of Longitudinal Ventilation on the Variation of Burning Rate in Tunnel Fires (터널 화재시 종류식 환기가 연소율 변화에 미치는 영향에 관한 실험적 연구)

  • Yang Seung Shin;Kim Sung Chan;Ryou Hong Sun
    • Tunnel and Underground Space
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    • v.15 no.1 s.54
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    • pp.55-60
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    • 2005
  • In this study, the 1/20 reduced-scale experiments using Froude scaling were conducted to investigate the effect of longitudinal ventilation on the variation of burning rate in tunnel fires. The methanol square pool fires with heat release rate ranging from 3.57 kW to 10.95 kW were used. The burning rate of fuel was obtained by measured mass using load cell and temperature distribution were measured by K-type theomocouples in order to investigate smoke movement. The wind tunnel was connected with one side of the tested tunnel, and logitudinal ventilation velocity in the tested tunnel was controlled by power of the wind tunnel. In methanol fire case, the increase in ventilation velocity decreased the turning rate due to the direct cooling of fire plume. For the same dimensionless velocity(V), homing rate decreased as the size of pool fire increased.

Development of SMH Actuator System Using Hydrogen-Absorbing Alloy

  • Kwon, Tae-Kyu;Jeon, Won-Suk;Pang, Du-Yeol;Choi, Kwang-Hun;Kim, Nam-Gyun;Lee, Seong-Cheol
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1328-1333
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    • 2005
  • This paper presents the temperature-pressure characteristics of a new SMH actuator using a Peltier module. The SMH actuator is characterized by its small size, low weight, noiseless operation, and compliance similar to that of the human body. The simple SMH actuator, consisting of the plated hydrogen-absorbing alloys as a power source, Peltier elements as a heat source, and a cylinder with metal bellows as a functioning part has been developed. To improve the thermal conductivity of the hydrogen-absorbing alloy, an assembly of copper pipes has been used. It is well known that hydrogen-absorbing alloys can reversibly absorb and desorb a large amount of hydrogen, more than about 1000 times of their own volume. The hydrogen equilibrium pressure increases when hydrogen is desorbed by heating of the hydrogen-absorbing alloys, whereas by cooling the alloys, the hydrogen equilibrium pressure decreases and hydrogen is absorbed. The new special metal hydride (SMH) actuator uses the reversible reaction between the heat energy and mechanical energy of a hydrogen absorbing alloys. The desirable characteristics of SMH actuator, which makes it suitable for the uses in medical and rehabilitation applications, have been also studied. For this purpose, the characteristics of the new SMH actuator for different temperature, pressure, and external load were explored.

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On/Off-Design/Transient Analysis of a 50KW Turbogenerator Gas Turbine Engine (50KW 터보제너레이터용 가스터빈 엔진의 설계점/ 탈설계/과도성능해석)

  • Kim, Su-Yong;Park, Mu-Ryong;Jo, Su-Yong
    • 연구논문집
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    • s.27
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    • pp.87-99
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    • 1997
  • Present paper describes on/off design performance of a 50KW turbogenerator gas turbine engine for hybrid vehicle application. For optimum design point selection, relevant parameter study is carried out. The turbogenerator gas turbine engine for a hybrid vehicle is expected to be designed for maximum fuel economy, ultra low emissions, and very low cost. Compressor, combustor, turbine, and permanent-magnet generator will be mounted on a single high speed (82,000 rpm) shaft that will be supported on air bearings. As the generator is built into the shaft, gearbox and other moving parts become unnecessary and thus will increase the system's reliability and reduce the manufacturing cost. The engine has a radial compressor and turbine with design point pressure ratio of 4.0. This pressure ratio was set based on calculation of specific fuel consumption and specific power variation with pressure ratio. For the given turbine inlet temperature, a rather conservative value of $1100^\circK$ was selected. Designed mass flow rate was 0.5 kg/sec. Parametric study of the cycle indicates that specific work and efficiency increase at a given pressure ratio and turbine inlet temperature. Off design analysis shows that the gas turbine system reaches self operating condition at N/$N_{DP}$ = 0.53. Bleeding air for turbine stator cooling is omitted considering low TIT and for a simple geometric structure. Various engine performance simulations including, ambient temperature influence, surging at part load condition. Transient analysis were performed to secure the optimum engine operating characteristics. Surge margin throughout the performance analysis were maintained to be over 80% approximately. Validation of present results are yet to be seen as the performance tests are scheduled by the end of 1998 for comparison.

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Improvement Method of Regional Insulation Standard through the Regional Heating Energy Demand Analysis (권역별 난방에너지 요구량 분석을 통한 단열기준 개선방안)

  • Kim, Jeong-Gook;Ahn, Byung-Lip;Jang, Cheol-Yong;Jeong, Hak-Geun;Haan, Chan-Hoon
    • KIEAE Journal
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    • v.13 no.4
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    • pp.43-48
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    • 2013
  • The effect of climate change has influenced humanity and ecosystem with tremendous changes in temperature. For the past 150 years, the national annual average temperature is 0.6 degree increased and the heating degree day reduced from April to November. However, December to January, the climate change was generated and the heating degree day increased. The blackout occured in 2011 and 2012 by increasing electricity consumption of heating and cooling equipment to the effects of climate change. That is because heating load accounted for 20% of building electric use. In this study, strengthening measures to reduce heating energy consumption is presented due to climate change in winter since 1980 to prevent blackout and reliable power supply for the building energy-saving design standards by Meteorological data provided by the National Weather Service were calculated using the heating degree days in order to present eighteen cities from 1980 to 2012. Insulation standards are presented to prevent black-out by the heating degree days. the heating energy demand was reduced almost 6% including 10% in Central, 5% in South and Jeju area based on strengthening of the insulation. It is applied to the entire country an annual economic effect of 250 billion won, and black-out can be prevented.

Verification Experiment of a Water-to-air Ground Source Multi-heat Pump System (물-공기 지열 멀티형 열펌프 시스템 실증연구)

  • Kim, Cheol-Woo;Kim, Byoung-Kook;Lee, Pyeong-Gang;Lim, Hyo-Jae;Kang, Shin-Hyung;Choi, Jong-Min
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.6 no.1
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    • pp.9-16
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    • 2010
  • The aim of this study is to verify the performance of water-to-air multi-heat pump system with a vertical U-tube GLHX(U-tube system) and a double tube GLHX(double tube system), which were installed in a school building located in Asan. For analyzing the performance of the GSHP system, we monitored various operating da~ including the water temperature of inlet and outlet of the ground heat exchanger, mass flow rate, and power consumption. Daily average COP of the single U-tube system and the double tube system were 4.5 and 4.2 at cooling mode and were 3.5 and 3.8 at heating mode. As a result, We know that performance of water-to-air multi-heat pump unit is reliable at actual condition operated in a part load conditions for all day.

A Study on Energy Reduction in an Outdoor Air Conditioning System for Semiconductor Manufacturing Cleanrooms Using Water Spray Humidification (반도체 클린룸용 외기공조시스템의 수분무 가습을 이용한 에너지절감에 관한 연구)

  • Song, Won-Il;Kim, Ki-Cheol;Yoo, Kyung-Hoon;Shin, Dae-Kun;Tae, Kyung-Eung;Kim, Yong-Sik;Park, Dug-Jun
    • Particle and aerosol research
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    • v.13 no.2
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    • pp.65-77
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    • 2017
  • In recent large-scale semiconductor manufacturing cleanrooms, the energy consumption in outdoor air conditioning (OAC) systems to heat, humidify, cool and dehumidify outdoor air(OA) represents about 40~50 % of the total cleanroom power consumption required to maintain cleanroom environment. Therefore, the assessment of energy consumption in outdoor air conditioning systems is essential for reducing the outdoor air conditioning load for a cleanroom. In the present study, an experiment with an outdoor air flow rate of $1,000m^3/h$ was conducted to compare the energy consumption in steam humidification, simple air washer, exhaust air heat recovery type air washer and dry cooling coil(DCC) return water heat recovery type air washer OAC systems. Besides, a numerical analysis was carried out to evaluate the annual energy consumption of the aforementioned four OAC systems. It was shown that the simple air washer, exhaust air heat recovery type air washer and DCC return water heat recovery type air washer OAC systems using water spray humidification were more energy-efficient than the steam humidification OAC system. Furthermore the DCC return water heat recovery type air washer OAC system was the most energy-efficient.

Generation characteristics of transparent BIPV module according to temperature change (건물일체형 투명 모듈의 온도 변화에 따른 발전 특성)

  • Park, Kyung-Eun;Kang, Gi-Hwan;Kim, Hyun-Il;Yu, Gwon-Jong;Jang, Dae-Ho;Lee, Moon-Hee;Kim, Jun-Tae
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.210-211
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    • 2007
  • Amid booming PV(photovoltaic) industry, BIPV(Building Integrated PV) is one of the best fascinating PV application technologies. To apply PV in building, variable factors should be reflected such as installation position, shading, temperature effect and so on. Especially a temperature should be considered, for it affects both electrical efficiency of PV module and heating and cooling load in building. Transparent PV modules were designed as finished material for spandrels are presented in this paper. The temperature variation of the modules with and without air gap and insulation were compared and analyzed. The results showed that the module with air gap and insulation has a much larger temperature variation than another transparent module. The temperature of the module reached by 55degree C under vertical irradiance of lower 500$W/m^2$. And the temperature difference between these modules was about 15degree C. To analyze the output performance of module according to temperature variation, separate module was manufactured and measured by sun-simulator. The results showed that 1 degree temperature rise reduced about 0.45% of output power.

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