• Title/Summary/Keyword: Thermal to Mechanical Energy Electric Conversion System

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An Experimental Study on LTD Stirling Engine (MM-7) for the Development of TM Electric Conversion System (TM발전변환기 개발을 위한 저온도차 스털링엔진(MM-7)의 성능실측 연구)

  • Kim, Yeongmin;Chen, Kuan;Chun, Wongee
    • Journal of Energy Engineering
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    • v.25 no.1
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    • pp.9-14
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    • 2016
  • This study has been carried out to develop TM (Thermal to Mechanical) conversion systems for electric power generation using one of the Low Temperature Differential (LTD) Stirling engines called MM-7 capable of harnessing low temperature waste heat whose temperature is only $20{\sim}30^{\circ}C$ above the ambient. Measurements were made on the torque and rpm for a number of temperature differentials between the engine hot and cold ends, which could be effectively applied in developing the most suitable configuration for the high performance TM (Thermal to Mechanical) conversion system.

Construction and Testing of a radiation-beam powered TA (ThermoAcoustic) washer for grease removal

  • Chen, Kuan;DaCosta, David H.;Kim, Yeongmin;Oh, Seung Jin;Chun, Wongee
    • Journal of the Korean Solar Energy Society
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    • v.35 no.1
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    • pp.21-28
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    • 2015
  • A small washer powered directly and solely by thermal radiation was constructed and tested to explore the feasibility of using solar energy or other types of thermal radiation for washing and cleaning. In principle, TA (ThermoAcoustic) washers have the benefits of simpler design and operation and fewer energy conversion processes, thus should be more energy efficient and cost less than electric washing/cleaning systems. The prototype TA converter we constructed could sustain itself with consistent fluid oscillations for more than 20 minutes when powered by either concentrated solar radiation or an IR (infrared) heater. The frequencies of water oscillations in the wash chamber ranged from 2.6 to 3.6 Hz. The overall conversion efficiency was lower than the typical efficiencies of TA engines. Change in water temperature had little effect on the oscillatory flow in the TA washer due to its low efficiency. On the other hand higher water temperatures enhanced grease removal considerably in our tests. Methods for measuring the overall conversion efficiency, frictional loss, and grease removal of the TA washing system we designed were developed and discussed.

Joining and Performance of Alkali Metal Thermal-to-electric Converter (AMTEC) (알칼리금속 열전기변환장치의 접합과 출력성능)

  • Suh, Min-Soo;Lee, Wook-Hyun;Woo, Sang-Kuk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.7
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    • pp.665-671
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    • 2017
  • The alkali-Metal Thermal-to-electric Converter (AMTEC) is one of the promising static energy conversion technologies for the direct conversion of thermal energy to electrical energy. The advantages over a conventional energy converter are its high theoretical conversion efficiency of 40% and power density of 500 W/kg. The working principle of an AMTEC battery is the electrochemical reaction of the sodium through an ion conducting electrolyte. Sodium ion pass through the hot side of the beta"-alumina solid electrolyte (BASE) primarily as a result of the pressure difference. This pressure difference across the BASE has a significant effect on the overall performance of the AMTEC system. In order to build the high pressure difference across the BASE, hermeticity is required for each joined components for high temperature range of $900^{\circ}C$. The AMTEC battery was manufactured by utilizing robust joining technology of BASE/insulator/metal flange interfaces of the system for both structural and electrical stability. The electrical potential difference between the anode and cathode sides, where the electrons emitted from sodium ionization and recombined into sodium, was characterized as the open-circuit voltage. The efforts of technological improvement were concentrated on a high-power output and conversion efficiency. This paper discusses about the joining and performance of the AMTEC systems.

Solar CO2-Reforming of Methane Using a Double-Layer Absorber (더블 레이어 흡수기를 이용한 고온 태양열 메탄-이산화탄소 개질반응)

  • Kim, Dong-Yeon;Lee, Jin-Gyu;Lee, Ju-Han;Seo, Tae-Beom
    • 한국태양에너지학회:학술대회논문집
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    • 2012.03a
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    • pp.267-273
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    • 2012
  • Solar reforming of methane with CO2 was successfully tested with a direct irradiated absorber on a parabolic dish capable of 5kWth solar power. And the new type of double-layer absorber-the front layer, porous metal foam which absorbs the radiation and transfers the heat from material to gas, and the back layer, catalytically-activated metal foam-was prepared, and its activity was tested by using electric furnace. Ni was applied as the active metal on the gamma-Al2O3 coated Ni metal foam for the preparation of the catalytically-activated metal foam layer. Compared to conventional direct irradiation of the catalytically activated metal foam absorber, this new type of double layer absorber is found to exhibit a superior reaction and thermal storage performance at the fluctuating incident solar radiation. In addition, unlike direct irradiation of the foam absorber, double layer absorber has better thermal resistance, which prevents the emergence of cracks caused by mechanical or thermal shock. The total solar power absorbed reached up to 3.25kW and the maximum CH4 conversion was almost 59%.

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Solar CO2-Reforming of Methane Using a Double-Layer Absorber (더블 레이어 흡수기를 이용한 고온 태양열 메탄-이산화탄소 개질반응)

  • Kim, Dong-Yeon;Shin, Il-Yoong;Lee, Ju-Han;Seo, Tae-Beom
    • 한국태양에너지학회:학술대회논문집
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    • 2011.11a
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    • pp.80-86
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    • 2011
  • Solar reforming of methane with CO2 was successfully tested with a direct irradiated absorber on a parabolic dish capable of 5kWth solar power. And the new type of double-layer absorber - the front layer, porous metal foam which absorbs the radiation and transfers the heat from material to gas, and the back layer, catalytically-activated metal foam - was prepared, and its activity was tested by using electric furnace. Ni was applied as the active metal on the gamma-Al2O3 coated Ni metal foam for the preparation of the catalytically-activated metal foam layer. Compared to conventional direct irradiation of the catalytically activated metal foam absorber, this new type of double layer absorber is found to exhibit a superior reaction and thermal storage performance at the fluctuating incident solar radiation. In addition, unlike direct irradiation of the foam absorber, double layer absorber has better thermal resistance, which prevents the emergence of cracks caused by mechanical or thermal shock. The total solar power absorbed reached up to 3.25kW and the maximum CH4 conversion was almost 59%.

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Production of Hydrogen from Methane by 3phase AC GlidArc Plasma (3상 교류 부채꼴 방전을 이용한 메탄으로부터 수소 생산)

  • Chun, Young-Nam;Kim, Seong-Cheon;Lim, Mun-Seup
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2232-2237
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    • 2007
  • Steam reforming and catalytic reforming of $CH_4$ conversion to produce synthesis gas require both high temperatures and high pressure. Non-thermal plasma is considered to be a promising technology for the hydrogen rich gas production from methane. In this study, three phase AC GlidArc plasma system was employed to investigate the effects of gas composition, gas flow rate, catalyst reactor temperature and applied electric power on the $CH_4$ and $H_2$ yield and the product distribution. The studied system consisted of three electrode and it connected AC generate power system different voltages. In this study, air was used for the partial oxidation of methane. The results showed that increasing gas flow rate, catalyst reactor temperature, or electric power enhanced $CH_4$ conversion and $H_2$ concentration. The reference conditions were found at a $O_2$/C molar ratio of 0.45, a feed flow rate of 4.9 ${\ell}$/min, and input power of 1kW for the maximum conversions of $CH_4$ with a high selectivity of $H_2$ and a low reactor energy density.

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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 2012 (설비공학 분야의 최근 연구 동향 : 2012년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwataik;Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Choi, Jong Min;Park, Jun-Seok;Kim, Sumin
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.25 no.6
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    • pp.346-361
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    • 2013
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2012. 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. The conclusions are as follows : (1) The research works on thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and valves, fuel cells and power plants, ground-coupled heat pumps, and general heat and mass transfer systems. Research issues are mainly focused on new and renewable energy systems, such as fuel cells, ocean thermal energy conversion power plants, and ground-coupled heat pump systems. (2) Research works on the 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 natural convection in a square enclosure with two hot circular cylinders, non-uniform grooved tube considering tube expansion, single-tube annular baffle system, broadcasting LED light with ion wind generator, mechanical property and microstructure of SA213 P92 boiler pipe steel, and flat plate using multiple tripping wires. In the area of pool boiling and condensing heat transfer, researches on the design of a micro-channel heat exchanger for a heat pump, numerical simulation of a heat pump evaporator considering the pressure drop in the distributor and capillary tubes, critical heat flux on a thermoexcel-E enhanced surface, and the performance of a fin-and-tube condenser with non-uniform air distribution and different tube types were actively carried out. In the area of industrial heat exchangers, researches on a plate heat exchanger type dehumidifier, fin-tube heat exchanger, an electric circuit transient analogy model in a vertical closed loop ground heat exchanger, heat transfer characteristics of a double skin window for plant factory, a regenerative heat exchanger depending on its porous structure, and various types of plate heat exchangers were performed. (3) In the field of refrigeration, various studies were executed to improve refrigeration system performance, and to evaluate the applicability of alternative refrigerants and new components. Various topics were presented in the area of refrigeration cycle. Research issues mainly focused on the enhancement of the system performance. In the alternative refrigerant area, studies on CO2, R32/R152a mixture, and R1234yf were performed. Studies on the design and performance analysis of various compressors and evaporator were executed. (4) In building mechanical system research fields, twenty-nine studies were conducted to achieve effective design of mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, renewable energy systems, and lighting systems in buildings. New designs and performance tests using numerical methods and experiments provide useful information and key data, which can improve the energy efficiency of buildings. (5) In the fields of the architectural environment, studies for various purposes, such as indoor environment, building energy, and renewable energy were performed. In particular, building energy-related researches and renewable energy systems have been mainly studied, reflecting interests in global climate change, and efforts to reduce building energy consumption by government and architectural specialists. In addition, many researches have been conducted regarding indoor environments.