• Title/Summary/Keyword: Heat reuse

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Analysis of Phase Change Materials for Production of Changable Mold for Free-form Concrete Segment (FCS 가변형 몰드 생산을 위한 PCM 분석)

  • Lee, Donghoon;Kim, Sunkuk
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.150-151
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    • 2014
  • A mold of free-form concrete segment can be used only one time. Thus, the construction duration and cost are increased. The materials of the mold such as wood and metal have limitations due to the implementation and reuse. The review of the material of the mold for free-form concrete segment is needed to reduce duration and production cost. Phase change material can be used both to implement free-shape by heating and to produce mold after cooling. After using Phase change material can be re-used to mold by heating. The scope of this study is many kind of phase change materials for molding. The aim of this study is to analyze the phase change materials for production of changable mold for free-form concrete segment. In this study, the paraffin wax that is melted at 64℃ was selected by considering both the energy efficiency and the weather of Korea.

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Study on high-Heated according Change of Fireproof Mortar Using Oyster Sell (굴 패각을 활용한 내화모르타르의 고온수열에 따른 성분변화에 관한 연구)

  • Hong, snag-hun;Jung, Ui-In;Kim, Bong-Joo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2017.05a
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    • pp.176-177
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    • 2017
  • IN order to use it for high-temperature fire, Fireproof boards mainly composed of Ca and Mg used. Korea does not have a fireproof board for explosive high temperatuer fire in tunnel, and it is applying existing fireproof coating. However, when a high-temperature fire(1350℃)with explosion occurs, it can not sustain its strength and can not be destroyed to have fire resistance. Each year, more than 100,100tons of wastes are produced by using Ca as an oyster shell. In this study, we try to determine whether or not to reuse the heat-heated fireproof board.

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The effect of heat to remove cement on implant titanium abutment and screw (시멘트 제거를 위해 가한 열이 임플란트 티타늄 지대주와 나사에 미치는 영향)

  • Yi, Hyo-Gyoung;Gil, Ki-Sung;Lee, Jung-Jin;Ahn, Seung-Geun;Seo, Jae-Min
    • The Journal of Korean Academy of Prosthodontics
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    • v.56 no.3
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    • pp.179-187
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    • 2018
  • Purpose: The purpose of this study was to investigate the effect of heat applied to disintegrate cement on the removal torque value and fracture strength of titanium abutment and abutment screw. Materials and methods: Implants, titanium abutments and abutment screws were prepared for each 20 piece. Implant abutments and screws were classified as the control group in which no heat was applied and the experimental group was heated in a vacuum furnace to $450^{\circ}C$ for 8 minutes and cooled in air. The abutments and screws were connected to the implants with 30 Ncm tightening torque at interval 10 minutes and the removal torque value was measured 15 minutes later. And the fracture strength of abutment screw was measured using universal testing machine. Results: The mean removal torque value was $27.84{\pm}1.07Ncm$ in the control group and $26.55{\pm}1.56Ncm$ in the experimental group and showed statistically significant difference (P < .05). The mean fracture strength was $731.47{\pm}39.46N$ in the control group and $768.58{\pm}46.73N$ in the experimental group and showed statistically no significant difference (P > .05). Conclusion: The heat applied for cement disintegration significantly reduced the removal torque value of the abutment screw and did not significantly affect fracture strength of the abutment screw. Therefore, in the case of applying heat to disintegrate cement it is necessary to separate the abutment screw or pay attention to the reuse of the heated screw. However further studies are needed to evaluate the clinical reuse of the heated screw.

An experimental study on performance evaluation for development of compact steam unit applied with hybrid plate heat exchanger (하이브리드 판형 열교환기 적용 컴팩트 스팀 유닛 개발을 위한 성능 평가에 관한 실험적 연구)

  • Park, Jae-Hong;Cho, Sung-Youl;Lee, Jun-Seok;Lee, Sang-Rae;Kim, Seung-Hyun;Lim, Gye-Hun;Seo, Jung-Wan;Kim, Jeung-Hoon
    • Journal of Advanced Marine Engineering and Technology
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    • v.41 no.4
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    • pp.296-301
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    • 2017
  • In various industrial places such as power generation plants, petrochemical and unit factories, the demands of systems that produce hot water by utilizing wasted or surplus steam have been increased. Compact steam unit(CSU) is a system that can meet these demands and produce hot water by using surplus or wasted steam, and it is also one of the good solutions in view of energy reuse. The new CSU with a capacity of 1,600 kW was developed with a hybrid plate heat exchanger of which thermal performances are better than a conventional plate heat exchanger, an improved temperature control valve, a user-friendly control system, and other components in this study. The purpose of this study was to obtain performance data of the new CSU through various experiments and utilize them for the CSU commercialization. The experimental results show that heat balances between the hot side(steam) and the cold side(cold water) were within ${\pm}0.77%$, and the fluctuations of outlet temperature of the secondary side which are one of the most important evaluation factors in the CSU were $(0{\sim}0.3)^{\circ}C$.

An Economic Analysis of the Effluent Heat Supply from Thermal Power Plant to the Farm Facility House (화력발전소 온배수열 활용 시설하우스 열공급 모형 경제성분석 연구)

  • Um, Byung Hwan;Ahn, Cha Su
    • Korean Chemical Engineering Research
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    • v.56 no.1
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    • pp.6-13
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    • 2018
  • Utilizing the heat of cooling water discharge of coal-fired power plant, pipeline investment costs for businesses that supply heat to agricultural facilities near power plants increase in proportion to installation distance. On one hand, the distance from the power plant is a factor that brings difficulties to secure economic efficiency. On the other, if the installation distance is short, there is a problem of securing the heating demands, facility houses, which causes economical efficiency to suffer. In this study, the economic efficiency of 1km length of standard heat pipeline was evaluated. The sensitivity of the heat pipe to the new length variation was analyzed at the level of government subsidy, amount of heating demand and the incremental rate of pipeline with additional government subsidy. As a result of the analysis, it was estimated that NPV 131 million won and IRR 15.73%. The sensitivity analysis showed that NPV was negative when the length of heat pipe facility exceeded 2.6 km. If the government supports 50% of the initial investment, the efficiency is secured within the estimated length of 5.3 km, and if it supports 80%, the length increases within 11.4 km. If the heat demand is reduced to less than 62% at the new length of the standard heat pipe, it is expected economic efficiency is not obtained. If the ratio of government subsidies to initial investment increases, the elasticity of the new bloc will increase, and the fixed investment, which is the cost of capital investment for one unit of heating demand, will decrease. This would result in a reduction in the cost of production per unit, and it would be possible to supply heat at a cheaper price level to the facility farming. Government subsidies will result in the increased economic availability of hot plumbing facilities and additional efficiencies due to increased demand. The greater government subsidies to initial investment, the less farms cost due to the decrease in the price per unit. The results of the study are significant in terms of the economic evaluation of the effectiveness of the government subsidy for the thermal power plant heat utilization project. The implication can be applied to any related pilot to come.

Technical Measures for Improving Energy Efficiency in Historic Buildings -Focused on Researches and Case Studies of the West- (역사적 건축물의 에너지 효율 향상을 위한 계획기법 -서양의 연구동향 및 사례를 중심으로-)

  • Kim, Tai-Young
    • Journal of the Korean Institute of Rural Architecture
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    • v.20 no.1
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    • pp.69-76
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    • 2018
  • This study is to research technical measures for improving energy efficiency in the conservation and reuse of historic buildings focused on the recent research trends and case studies of the west. These measures are broadly classified into three types, the passive measures for saving energy and increasing comfort, the most cost-effective energy saving strategies, and the renewable energy sources. Firstly, the passive measures are divided into the elements and systems. The passive elements are awnings and overhanging eaves, porches, shutters, storm windows and doors, and shade trees. There are also the natural ventilation systems such as the historic transoms, roofs and attics to improve airflow and cross ventilation to either distribute, or exhaust heat. Secondly, the most cost-effective energy efficiency strategies are the interior insulation, airtightness and moisture protection, and the thermal quality improvement of windows. The energy efficiency solutions of modern buildings are the capillary-active interior insulation, the airtightness and moisture protection of interior walls and openings, and the integration of the original historic window into the triple glazing. Beyond the three actions, the additional strategies are the heat recovery ventilation, and the illumination system. Thirdly, there are photovoltaic(PV) and solar thermal energy, wind energy, hydropower, biomass, and geothermal energy in the renewable energy sources. These energy systems work effectively but it is vital to consider its visual effect on the external appearance of the building.

Characterization of Wood Chip Ash Generated from a Power Plant (열병합 발전소에서 발생한 우드칩 분진에 대한 특성 분석)

  • Bang, Jung Won;Kim, Soo-Ryong;Kim, Younghee;Kim, Mido;Kang, Won-Seok;Cho, Kye-Hong;Kwon, Woo-Teck
    • Resources Recycling
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    • v.26 no.1
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    • pp.11-15
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    • 2017
  • The amount of the wood chip ash is expected to increase continuously as demand of wood chip-based heat and electricity increase. Thus, there is increased interest in wood chip ash utilization. In this study, as a program of utilization in wood chip ash, the physical and chemical properties of wood chip ashes generated from a combined heat and power plant were investigated. The chemical analysis showed that the main contents of wood chip ash are composed of silica, alumina and alkali. A possibility of reuse as secondary cementitious materials was investigated by the analysis of strength activity index, and compared with coal ash. The highest value for Strength activity index of wood chip fly ash was 78% at 90 days curing time. This result revealed that wood chip fly ash has the potential to be utilized as the admixture for cementitious material.

Characteristics of Splitting Solid Amount by Friendly Environmental CFB Boiler's Particle Re-circulating Device (환경친화적 CFB 보일러 입자재순환 장치의 고체량 분배 특성)

  • Kim, You-Seok;Hwang, Jae-Dong;Choi, Yong-Joon;Moon, Kil-Ho;Shun, Do-Won;Bae, Dal-Hee
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1756-1760
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    • 2004
  • Circulating Fluidized-Bed (CFB) boilers which have been operated in Korea were manufactured by the design technology of foreign leading companies. As they are not active to transfer their technology, domestic companies don't have the enough ability to design it independently yet. Doosan Heavy Industries & Construction Co. Ltd. and Korean Institute of Energy Research are trying to develop and improve the particle re-circulating device among the components of CFB boiler. Our purpose is to control the amount of particles leaving the re-circulating system by adjusting utility air and reuse the heat of circulating particles. The results of experiments with cold model system show that a fluidization state in the particle re-circulating device is very stable when the amount of utility air is supplied to its wind box with 2.29 times of minimum fluidization velocity. Also the amount of particles entering the riser don't increase linearly when the amount of utility air is supplied over 2.5 times of minimum fluidization velocity. Now we are testing its functional run with the hotstate experiment set-up.

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An Experimental Study of KTP Crystal Growing by TSSG Method (TSSG 법에 의한 KTP 단결정 성장의 실험적 연구)

  • 김형천;윤경구
    • Korean Journal of Crystallography
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    • v.4 no.1
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    • pp.42-48
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    • 1993
  • KTP(KTiOPO4) single crystals were grown by the TSSG(top seeded solution growth) method using the Ksp401s flux. A heat-pipe based growing furnace was used, and the temperature stability and the homogenity of the growing solution in the platinum crucible were within the level of It 0.5℃ and ±0.9℃, respectively. The effects of some operating variables such as operating temperature range, initial cooling rate, forced stirring, reuse of the flux were investigated. As the initial cooling rate was decreased to the degree of 0.1℃/hr and some proper stirring effect by the crystal rotation was introduced to the present experimental condition, bigger and better crystals without inclusion grew. A single crystal with the maximum sixte of 44 ×39 ×17mm3 was obtained and showed the SHG conversion efficiency of 21.39) even without the anti-refilection coating.

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Proteomic Evaluation of Cellular Responses of Saccharomyces cerevisiae to Formic Acid Stress

  • Lee, Sung-Eun;Park, Byeoung-Soo;Yoon, Jeong-Jun
    • Mycobiology
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    • v.38 no.4
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    • pp.302-309
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    • 2010
  • Formic acid is a representative carboxylic acid that inhibits bacterial cell growth, and thus it is generally considered to constitute an obstacle to the reuse of renewable biomass. In this study, Saccharomyces cerevisiae was used to elucidate changes in protein levels in response to formic acid. Fifty-seven differentially expressed proteins in response to formic acid toxicity in S. cerevisiae were identified by 1D-PAGE and nano-liquid chromatography-tandem mass spectrometry (nano-LC-MS/MS) analyses. Among the 28 proteins increased in expression, four were involved in the MAP kinase signal transduction pathway and one in the oxidative stress-induced pathway. A dramatic increase was observed in the number of ion transporters related to maintenance of acid-base balance. Regarding the 29 proteins decreased in expression, they were found to participate in transcription during cell division. Heat shock protein 70, glutathione reductase, and cytochrome c oxidase were measured by LC-MS/MS analysis. Taken together, the inhibitory action of formic acid on S. cerevisiae cells might disrupt the acidbase balance across the cell membrane and generate oxidative stress, leading to repressed cell division and death. S. cerevisiae also induced expression of ion transporters, which may be required to maintain the acid-base balance when yeast cells are exposed to high concentrations of formic acid in growth medium.