• 제목/요약/키워드: Thermal output

검색결과 641건 처리시간 0.031초

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

  • 송영학;김기태;구보경;이건호
    • 설비공학논문집
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    • 제26권1호
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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.

An Analysis of Shielding Design of TRIGA Mark-II Reactor

  • Lee, Chang-Kun
    • Nuclear Engineering and Technology
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    • 제3권4호
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    • pp.185-197
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    • 1971
  • 1950년대의 미국 General Atomic사에서 열출력 100 kw로 설계, 제작하여 1962년 3월에 건조완료한 TRIGA Mark-II원자로는 1969년 7월에 250 kw로 출력 증강되었으나 방사선차폐는 보강되지 않았다. 본 논문에서의 계산에 의하면 출력 증강후 현재의 차폐물로도 중성자에 대하여는 확실히 안전하지만 Gamma선에 대해서는 위험하다는 것이 판명되었다. 원자로의 구조와 출입인 및 실험종사자들의 위치로 보아 차폐물의 안전도 검토는 수평방향에 한하였고, 또 정확을 기하기 위하여 중성자와 Gamma선의 투과문제를 나누어 검토하였다. 이를 근거로 하여 이론적인 측면에서 본 콘크리트의 보강을 요하는 두께도 산출하였다.

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습식 압축을 채용한 재생 가스터빈 사이클의 엑서지 해석 (Exergy Analysis of Regenerative Wet-Compression Gas-Turbine Cycles)

  • 김경훈;김세웅;고형종
    • 에너지공학
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    • 제18권2호
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    • pp.93-100
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    • 2009
  • 습식압축으로 압축소요동력을 줄이고 재생기로 배기가스 에너지를 회수함으로써 열효율을 향상시킬 수 있는 습식압축 재생 브레이튼 사이클에 대하여 엑서지 해석을 수행하였다. 해석모델을 통하여 시스템의 엑서지 효율과 요소별 엑서지 파괴비 및 배기가스로 인한 엑서지 손실비에 미치는 압력비와 물분사율의 영향을 조사하였다. 전형적인 운전조건에 대한 계산 결과 습식압축 재생 가스터빈 사이클에 의하여 엑서지 효율을 상당히 향상시킬 수 있음을 확인하였다. 물 분사 효과는 배기가스의 엑서지 손실의 감소와 출력 동력의 증가로 나타난다.

MEMS 기반의 차량용 휨형 유속센서의 제작 및 특성 연구 (Study on the Fabrication and Evaluation of the MEMS Based Curved Beam Air Flowmeter for the Vehicle Applications)

  • 박철민;최대근;이상훈
    • 센서학회지
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    • 제25권2호
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    • pp.116-123
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    • 2016
  • This paper presents the fabrication and evaluation of the novel drag force type air flowmeter using MEMS technologies for the vehicle applications. To obtain the air drag force, the flowmeter utilized the curved beam structure, which was realized by the difference of residual stress between the silicon oxide layer and the silicon nitride layer. The paddle structure was applied for the maximum air drag force, and the dual-beam was adapted to prevent distortion. The basic experiments were performed in the wind tunnel, and the stable outputs were obtained. The device was applied to the internal combustion engine, and the results were compared with the HI-DS output where the convection thermal flowmeter was used as the reference sensor. The results indicated that the comparable resolutions and response times were obtained under the various engine speeds.

Construction of a 40-channel SQUID System and Its Application to Neuromagnetic Measurements

  • Lee, Y.H.;Kim, J.M.;Kwon, H.C.;Park, Y.K.;Park, J.C.;Lee, D.H.;Ahn, C.B.
    • Progress in Superconductivity
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    • 제2권1호
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    • pp.20-26
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    • 2000
  • A 40-channel superconducting quantum interference device (SQUID) system was constructed for measuring neuromagnetic fields. Main features of the system are the use of double relaxation oscillation SQUIDs (DROSs), and planar gradiometers measuring magnetic field components tangential to the head surface. The DROSs with high flux-to-voltage transfers enabled direct readout of the SQUID output by room-temperature dc preamplifiers and simple flux-locked loop circuits could be used for SQUID operation. The pickup coil is an integrated first-order planar gradiometer with a baseline of 40 mm. Average noise level of the 40 channels is around 1.2 $fT/cm/{\surd}Hz$ at 100 Hz, corresponding to a field noise of 5 $fT/{\surd}Hz$, operated inside a magnetically shielded room. The SQUID insert was designed to have low thermal load, minimizing the loss of liquid helium. The constructed system was applied to measure auditory-evoked neuromagnetic fields.

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LNG 냉열을 열싱크로 이용하는 유기랭킨사이클(ORC)의 작동유체에 따른 성능 특성 (Effects of Working Fluids on the Performance Characteristics of Organic Rankine Cycle (ORC) Using LNG Cold Energy as Heat Sink)

  • 김경훈;하종만;김경천
    • 한국수소및신에너지학회논문집
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    • 제25권2호
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    • pp.200-208
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    • 2014
  • This paper presents thermodynamic performance analysis of organic Rankine cycle (ORC) using low temperature heat source in the form of sensible energy and using liquefied natural gas (LNG) as heat sink to recover the cryogenic energy of LNG. LNG is able to condense the working fluid at a very low condensing temperature in a heat exchanger, which leads to an increased power output. Based on the mathematical model, a parametric analysis is conducted to examine the effects of eight different working fluids, the turbine inlet pressure and the condensation temperature on the system performance. The results indicate that the thermodynamic performance of ORC such as net work production or thermal efficiency can be significantly improved by the LNG cold energy.

Combined Economic and Emission Dispatch with Valve-point loading of Thermal Generators using Modified NSGA-II

  • Rajkumar, M.;Mahadevan, K.;Kannan, S.;Baskar, S.
    • Journal of Electrical Engineering and Technology
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    • 제8권3호
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    • pp.490-498
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    • 2013
  • This paper discusses the application of evolutionary multi-objective optimization algorithms namely Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and Modified NSGA-II (MNSGA-II) for solving the Combined Economic Emission Dispatch (CEED) problem with valve-point loading. The valve-point loading introduce ripples in the input-output characteristics of generating units and make the CEED problem as a non-smooth optimization problem. IEEE 57-bus and IEEE 118-bus systems are taken to validate its effectiveness of NSGA-II and MNSGA-II. To compare the Pareto-front obtained using NSGA-II and MNSGA-II, reference Pareto-front is generated using multiple runs of Real Coded Genetic Algorithm (RCGA) with weighted sum of objectives. Furthermore, three different performance metrics such as convergence, diversity and Inverted Generational Distance (IGD) are calculated for evaluating the closeness of obtained Pareto-fronts. Numerical results reveal that MNSGA-II algorithm performs better than NSGA-II algorithm to solve the CEED problem effectively.

주거건물에서의 통합 실내환경평가 가중치 분석을 통한 거주자 특성분석 - 충북지역 주거건물 거주자 설문조사를 바탕으로 (Occupant Characteristics Analysis based on Integrative IEQ Weighting Factor in Residential Buildings - Based on Occupant Survey of Residential Building in Chungbuk Province)

  • 윤성훈;윤희진
    • KIEAE Journal
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    • 제16권5호
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    • pp.87-92
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    • 2016
  • Purpose: The objective of this research is to investigate and analyze the relationship between physical residential conditions and occupants' responses in apartment buildings by POE(Post-Occupancy Evaluation). The analysis results from this research will help to identify the indoor residential problems and find design solutions for improving overall residential indoor residential environment. Method: The occupant survey was conducted at four different apartment complex area at Cheongju City, Chungbuk Province, Korea. Combination of unbalanced indoor environmental conditions in residential building had difference of occupants' responses according to occupants' characteristics, such as gender, age, and so on. The survey collected data regarding the occupants' EQ(Environmental Quality) priorities to determine the weight of each environmental-quality factor (lighting, acoustic, thermal and indoor air quality). A paired comparison method was used to determine the weight by comparing the relative importance of the two factors based on occupant's survey response. Result: The output from this research is useful to understand the residential environment, occupants' satisfaction, preference, and identifies the current residential problems and finds an architectural solution in apartment buildings.

Unison U50 직접구동 영구자석 발전기를 기반으로 한 900kW급 동기발전기 설계 및 최적화 (Design and optimization of 900kW class PMSG, based on Unison U50 model)

  • 김태훈;이상우;김동언;정진화;박현철
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2009년도 추계학술대회 논문집
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    • pp.423-426
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    • 2009
  • POSTECH Graduate School of Wind Energy is trying to upgrade the PMSG used for Unison U50 to 900 kW class. Intensive optimization efforts are carried out the reduce the axial size and total weight of the generator while increasing the rated output to 900 kW. The generator features 3.32m stator inner radius, 671mm stator length, 84 pole, 25 rated rpm and 31.6kN/$m^2$ shear force density. To reduce the gross weight, the stronger magnetic material is applied with optimal magnet size resulting lowest cogging torque. Also, instead of stator skewing the stator, the magnet position along the circumference is optimized to further reduce the cogging torque. This scheme eliminates the stator skewing procedure and may enhance the productivity. This method also reduces the total harmonic distortion. In this report, upgrade method, no-load line to line voltage and phase voltage, cogging torque, loss calculations and thermal analysis are presented.

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자외선 나노초 펄스 레이저를 이용한 경연성(Rigid Flexible) 인쇄전자회로기판(Printed Circuit Board) 고속 절단에 관한 연구 (Study on High Speed Laser Cutting of Rigid Flexible Printed Circuit Board by using UV Laser with Nano-second Pulse Width)

  • 배한성;박희천;류광현;남기중
    • 한국정밀공학회지
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    • 제27권2호
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    • pp.20-24
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    • 2010
  • High speed cutting processes of rigid flexible printed circuit board by making use of high power UV laser with nano-second pulse width have been proposed and investigated experimentally. Also robust laser cutting system has been designed and developed in order to obtain a good cutting quality of rigid and flexible PCB with multi-layers (2-6 layers). Power controller module developed for ourselves is adapted to control the laser output power in the range less than 1%. The systems show the good performance of cutting speed, cutting width and cutting accuracy, respectively. Especially we have confirmed that the short circuit problem due to the carbonized contamination occurred in cross section of multi-layers by thermal effect of high power laser has been improved largely by using multi-pass cutting process with low power and high speed.