• Title/Summary/Keyword: Heat Recovery Unit

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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.

Optimization of three small-scale solar membrane distillation desalination systems

  • Chang, Hsuan;Hung, Chen-Yu;Chang, Cheng-Liang;Cheng, Tung-Wen;Ho, Chii-Dong
    • Membrane and Water Treatment
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    • v.6 no.6
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    • pp.451-476
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    • 2015
  • Membrane distillation (MD), which can utilize low-grade thermal energy, has been extensively studied for desalination. By incorporating solar thermal energy, the solar membrane distillation desalination system (SMDDS) is a potential technology for resolving the energy and water resource problems. Small-scale SMDDS (s-SMDDS) is an attractive and viable option for the production of fresh water for small communities in remote arid areas. The minimum-cost design and operation of s-SMDDS are determined by a systematic method, which involves a pseudo steady state approach for equipment sizing and the dynamic optimization using overall system mathematical models. The s-SMDDS employing three MD configurations, including the air gap (AGMD), direct contact (DCMD) and vacuum (VMD) types, are optimized. The membrane area of each system is $11.5m^2$. The AGMD system operated for 500 kg/day water production rate gives the lowest unit cost of $5.92/m^3$. The performance ratio and recovery ratio are 0.85 and 4.07%, respectively. For the commercial membrane employed in this study, the increase of membrane mass transfer coefficient up to two times is beneficial for cost reduction and the reduction of membrane heat transfer coefficient only affects the cost of the DCMD system.

Development of Carbon Dioxide Emission Factor from Resource Recovery Facility (폐기물자원회수시설의 이산화탄소 배출계수 개발)

  • Kim, Seungjin;Im, Gikyo;Yi, Chi-Yeong;Lee, Seehyung;Sa, Jae-Hwan;Jeon, Eui-Chan
    • Journal of Climate Change Research
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    • v.4 no.1
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    • pp.51-61
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    • 2013
  • To address the problems associated with climate change and energy shortage, Korea has been making efforts to turn waste materials into usable energy. Due to the ongoing efforts to convert waste materials into energy, waste incineration is expanding to utilize the heat generated, and the subsequent greenhouse gas emissions from these waste material incineration are expected to increase. In this study, a municipal waste incineration plant that generates heat and electricity through heat recovery was selected as a subject facility. Methods for estimating the greenhouse gas emissions in the municipal waste incineration plant that was selected as a subject plant were sought, and the greenhouse gas emissions and emission factor were estimated. The $CO_2$ concentrations in discharge gas from the subject facility were on average 6.99%, and the result from calculating this into greenhouse gas emissions showed that the total amount of emissions was $254.60ton\;CO_2/day$. The net emissions, excluding the amount of greenhouse gas emitted from biomass incineration, was shown to be $110.59ton\;CO_2/day$. In addition, after estimating the emissions by separating the heat and electricity generated in the incineration facility, greenhouse gas emission factors were calculated using the greenhouse gas emissions produced per each unit of output. The estimated emission factor for heat was found to be $0.047ton\;CO_2/GJ$ and the emission factor for electricity was found to be $0.652ton\;CO_2/MWh$. The estimated emission factor was shown to be about 17% lower than the $0.783ton\;CO_2/MWh$ emission factor for thermal power plants that use fossil fuels. Waste material types and fossil carbon contents were evaluated as being the factors that have major effects on the greenhouse gas emissions and emission factor.

Investigation on Recuperative Cycle Gas Turbine Engine for Power Generation (발전용 가스터빈에서의 Recuperative 사이클 적용성 검토)

  • Kim SooYong;Son Ho-Jae;Goldenberg Victor
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • v.y2005m4
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    • pp.225-230
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    • 2005
  • It is theoretically known that recuperator can bring a significant increase in thermal efficiency of the gas turbine unit, but it also has disadvantages such as pressure loss in the flow channel, thermal stress and increase in weight. Therefore it is necessary to consider all pros and cons of this equipment in view of economic aspects throughout its life cycle. Recuperator has been applied mostly in the power ranges of $20\sim300kW$ class industrial units but hasn't been used as a larger power generation unit except for naval applications in mid twentieth century. Present paper considered the applicability of a recuperator cycle in term of pressure loss, part load aspects for power generation purpose.

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Performance improvement of BOP Components for 1kW Stationary Fuel Cell Systems to Promote Green-Home Dissemination Project (그린홈 보급확대를 위한 건물용 연료전지 보조기기의 성능 향상)

  • Lee, Sunho;Kim, Dongha;Kim, Minseok;Jun, Heekwon
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.89.1-89.1
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    • 2011
  • According to green growth's policy, green-home dissemination's projects are promoting. Among them, stationary fuel cell systems are receiving attention due to high efficiency and clear energy. But it need absolutely to develop cost down technologies and improve system durability for commercialization of the fuel cell system. To achieve this objectives, in 2009, the Korean Government and "Korea Institute of Energy Technology Evaluation and Planning(KETEP)" launched into the strategic development project of BOP technology for practical applications and commercializations of stationary fuel cell systems, named "Technology Development on Cost Reduction of BOP Components for 1kW Stationary Fuel Cell Systems to Promote Green-Home Dissemination Project". This paper introduces a summary of improved BOP performances that has been achieved through the 2nd year development precesses(2010.06~2011.05) base on 1st year development precesses(2009.06~2010.05). The major elements for fuel cell systems are cathode air blowers, burner air blowers, preferential oxidation air blowers, fuel blowers, cooling water pumps, reformer water pumps, heat recovery pumps, mass flow meters, electrical valves, safety valves and a low-voltage inverter. Key targets of those elements are the reduction of cost, power consumption and noise. Invert's key targets are development the low -voltage technologies in order to reduce the number of unit cell in fuel cell system's stack.

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Analysis of environmental benefit of wood waste recycling processes (폐목재 자원화 방법 환경편익 분석)

  • Kim, Mi Hyung;Hong, Soo Youl;Phae, Chae Gun;Koo, Ja Kong
    • Journal of the Korea Organic Resources Recycling Association
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    • v.20 no.2
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    • pp.15-19
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    • 2012
  • Wood wastes could be renewable resources by recycling as particleboard manufacturing or energy production. Particle board is the most common item of wood waste recycling and energy production from wood wastes has highlighted for energy recovery to reduce greenhouse gas generation in recent years. The aim of this study was to evaluate the environmental benefits of the processes for particle board manufacturing and energy production. The functional unit was one ton of wood wastes and the environmental impact was analyzed by life cycle assessment methodology. The result was that 112kg of carbon dioxide equivalent was produced from particle board manufacturing process and 382kg of carbon dioxide equivalent was produced from combined heat and power generation process. The concept of temporary biomass carbon storage was to applied to this study.

UNCERTAINTY AND SENSITIVITY ANALYSIS OF TMI-2 ACCIDENT SCENARIO USING SIMULATION BASED TECHNIQUES

  • Rao, R. Srinivasa;Kumar, Abhay;Gupta, S.K.;Lele, H.G.
    • Nuclear Engineering and Technology
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    • v.44 no.7
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    • pp.807-816
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    • 2012
  • The Three Mile Island Unit 2 (TMI-2) accident has been studied extensively, as part of both post-accident technical assessment and follow-up computer code calculations. The models used in computer codes for severe accidents have improved significantly over the years due to better understanding. It was decided to reanalyze the severe accident scenario using current state of the art codes and methodologies. This reanalysis was adopted as a part of the joint standard problem exercise for the Atomic Energy Regulatory Board (AERB) - United States Regulatory Commission (USNRC) bilateral safety meet. The accident scenario was divided into four phases for analysis viz., Phase 1 covers from the accident initiation to the shutdown of the last Reactor Coolant Pumps (RCPs) (0 to 100 min), Phase 2 covers initial fuel heat up and core degradation (100 to 174 min), Phase 3 is the period of recovery of the core water level by operating the reactor coolant pump, and the core reheat that followed (174 to 200 min) and Phase 4 covers refilling of the core by high pressure injection (200 to 300 min). The base case analysis was carried out for all four phases. The majority of the predicted parameters are in good agreement with the observed data. However, some parameters have significant deviations compared to the observed data. These discrepancies have arisen from uncertainties in boundary conditions, such as makeup flow, flow during the RCP 2B transient (Phase 3), models used in the code, the adopted nodalisation schemes, etc. In view of this, uncertainty and sensitivity analyses are carried out using simulation based techniques. The paper deals with uncertainty and sensitivity analyses carried out for the first three phases of the accident scenario.

Analysis on the Performance and the Emission of the Integrated Gasification Combined Cycle Using Heavy Oil (중잔사유 가스화 복합발전 사이클의 성능 및 환경배출 해석)

  • Lee, Chan;Yun, Yong-Seong
    • Journal of Energy Engineering
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    • v.10 no.3
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    • pp.188-194
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    • 2001
  • The process simulations are made on the IGCC power plant using heavy residue oil from refinery process. In order to model combined power block of IGCC, the present study employs the gas turbine of MS7001FA model integrated with ASU (Air Separation Unit), and considers the air extraction from gas turbine and the combustor dilution by returned nitrogen from ASU. The exhaust gas energy of gas turbine is recovered through the bottoming cycle with triple pressure HRSG (Heat Recovery Steam Generator). Clean syngas fuel of the gas turbine is assumed to be produced through Shell gasification of Visbreaker residue oil and Sulfinol-SCOT-Claus gas cleanup processes. The process optimization results show that the best efficiency of IGCC plant is achieved at 20% air extraction condition in the case without nitrogen dilution of gas turbine combustor find at the 40% with nitrogen dilution. Nitrogen dilution of combustor has very favorable and remarkable effect in reducing NOx emission level, while shifting the operation point of gas turbine to near surge point.

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The developments of heavy hydrocarbon reformer for SOFC

  • Bae, Jung-Myeon
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2012.05a
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    • pp.58.2-58.2
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    • 2012
  • Heavy hydrocarbon reforming is a core technology for "Dirty energy smart". Heavy hydrocarbons are components of fossil fuels, biomass, coke oven gas and etc. Heavy hydrocarbon reforming converts the fuels into $H_2$-rich syngas. And then $H_2$-rich syngas is used for the production of electricity, synthetic fuels and petrochemicals. Energy can be used efficiently and obtained from various sources by using $H_2$-rich syngas from heavy hydrocarbon reforming. Especially, the key point of "Dirty energy smart" is using "dirty fuel" which is wasted in an inefficient way. New energy conversion laboratory of KAIST has been researched diesel reforming for solid oxide fuel cell (SOFC) as a part of "Dirty energy smart". Diesel is heavy hydrocarbon fuels which has higher carbon number than natural gas, kerosene and gasoline. Diesel reforming has difficulties due to the evaporation of fuels and coke formation. Nevertheless, diesel reforming technology is directly applied to "Dirty fuel" because diesel has the similar chemical properties with "Dirty fuel". On the other hand, SOFC has advantages on high efficiency and wasted heat recovery. Nippon oil Co. of Japan recently commercializes 700We class SOFC system using city gas. Considering the market situation, the development of diesel reformer has a great ripple effect. SOFC system can be applied to auxiliary power unit and distributed power generation. In addition, "Dirty energy smart" can be realized by applying diesel reforming technology to "Dirty fuel". As well as material developments, multidirectional approaches are required to reform heavy hydrocarbon fuels and use $H_2$-rich gas in SOFC. Gd doped ceria (CGO, $Ce_{1-x}Gd_xO_{2-y}$) has been researched for not only electrolyte materials but also catalysts supports. In addition, catalysts infiltrated electrode over porous $La_{0.8}Sr_{0.2}Ga_{0.8}Mg_{0.2}O_3-{\delta}$ and catalyst deposition at three phase boundary are being investigated to improve the performance of SOFC. On the other hand, nozzle for diesel atomization and post-reforming for light-hydrocarbons removal are examples of solving material problems in multidirectional approaches. Likewise, multidirectional approaches are necessary to realize "Dirty energy smart" like reforming "Dirty fuel" for SOFC.

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