• Title/Summary/Keyword: Heat reservoir

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Property Change of Heat-reservoir Refractory Brick With Varying Compositions and Sintering Conditions Utilizing Mill-scale and Red-firing Clay As Raw Materials (밀스케일과 적점토를 원료로한 축열재에서 원료성분과 소성조선에 따른 특성 변화)

  • Kim, Jeong-Seog;Kim, Hong
    • Resources Recycling
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    • v.8 no.1
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    • pp.23-28
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    • 1999
  • Firing characteristics, transverse rupture strength, and heat capacity were studied of the heat-reservoir refractory materials made of red-firing clay, mill scale, and water glass. The firing shrinkage increased with increase of the clay proportion in samples. The volume of fired bodies showed shrinkage by drying up to $300^{\circ}C$, steady expansion in the 300-$700^{\circ}C$ range due to phase transition of iron oxides. and drastic expansion above $1200^{\circ}C$. Flexural strength decreased from 5.6 Mpa to 2.35 Mpa with the decrease of the ratio of clay to mill scale from 1:1 to 1:3 Heat capacities changed from 1.1 Joul/g$^{\circ}$C to 1.35 Joul/g$^{\circ}$C with the ratio of millscale to clay ratio from 1:1 to 1:3. Mill scale in the specimen appears to exist as liquid phase during firing. Firing the specimens in air leads to the eruption of the molten mill scale to the sample surfaces. Contrarily, firing samples in a refractory sagger with a cover suppressed the eruption of the molten mill scale to the surfaces. The addition of mill scale gave rise to porous sintered bodies which would delay cooling rates of heat-reservoir brick.

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Evaluation of Mitigation Effect of Upo-Swamp on the Air temperature Variation with Nighttime Cooling Rate (야간 냉각율을 이용한 우포늪의 기온변화 완화효과 평가)

  • Park, Myung-Hee;Kim, Hae-Dong
    • Journal of Environmental Science International
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    • v.20 no.3
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    • pp.309-319
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    • 2011
  • In this study, we investigated the effects of Upo-swamp upon local thermal environment with nighttime cooling rate. To do this, we set up the AWS(Automatic Weather observation System) over the central part of Upo-swamp on the early October 2007. We conducted the study by comparing the AWS data with another weather data observed by several meteorological observations of the Korea Meteorological Administration located at the vicinity of Upo-swamp for one year. The air temperature of Upo-swamp was higher than that of the surrounding in cold-climate season. But it was opposite in warm-climate season. We confirmed that Upo-swamp roles to mitigate the daily and annual air temperature ranges. And the daily air temperature variation of Upo-swamp lagged behind the land one. This phenomenon represent that the heat reservoir capacity of Upo-swamp is much larger than that of the ground.

Study on the Simulation of Heat Pump Heating and Cooling Systems to Hospital Building (병원 건물의 히트펌프 냉난방 시스템 적용을 위한 시뮬레이션 연구)

  • Choi, Young-Don;Han, Seong-Ho;Cho, Sung-Hwan;Kim, Du-Sung;Um, Chul-Jun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.32 no.4
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    • pp.275-282
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    • 2008
  • In Korea, air source heat pump system is less efficient than conventional heat source facilities, because the air temperature in winter season is so low that COP of air source heat pump system drops below 3.0. Therefore, the study on the application of heat pump heating and cooling systems is crucial for the efficient popularization of heat pump. In this work, we present the dynamic analysis of energy consumption for the large hospital building by heat resistance-capacitance method. The system simulation of water storage air source heat pump is additionally performed by changing sizes and locations of the hospital building. The computed results show that energy cost of water storage air source heat pump is low, so it is more economical than absorption chiller & heater.

Study on the Simulation of Heat Pump Heating and Cooling Systems to Resident Building (숙박업소 건물의 히트펌프 냉난방 시스템 적용을 위한 시뮬레이션 연구)

  • Choi, Young-Don;Han, Seong-Ho;Cho, Sung-Hwan;Kim, Ju-Sung;Um, Chul-Jun
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.915-920
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    • 2006
  • Recently available heat pump system by using air heat-source is not efficient. Because the mean temperature of korean winter season is low, economy of air heat-source heat pump descend, and COP is below 3.0. This paper was practiced the simulation on evaluation criteria for heat pump heating and cooling systems to resident building. As a result, heating and cooling composition heat pump system apply to the building needed to be provided heat source for 24 hours.

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Ortho-to-Para Ratio Studies of Shocked $H_2$ Gas Observed from Two Supernova Remnants IC 443 and HB 21

  • Shinn, Jong-Ho;Lee, Ho-Gyu;Moon, Dae-Sik
    • The Bulletin of The Korean Astronomical Society
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    • v.38 no.1
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    • pp.48.2-48.2
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    • 2013
  • We present the near-infrared spectra (2.5-5.0 um) of shocked $H_2$ gas, observed with the Infrared Camera onboard the satellite AKARI. Two supernova remnants, IC 443 and HB 21, were observed. IC 443 shows a hint of non-equilibrium ortho-to-para ratio (OPR): 2.4 (-0.2, +0.3). HB 21 also shows an indication of a potential non-equilibrium OPR: 1.8-2.0. These non-equilibrium OPRs are first reported for shocked $H_2$ gas at E(v,J) > 7000 K, as far as we are aware. We concluded that the non-equilibrium OPR probably originates from dissociative J-shocks, considering several factors such as the shock combination requirement, the line ratios, and the possibility that $H_2$ gas can form on grains with a non-equilibrium OPR. The difference in the collision energy of H atoms on grain surfaces would give rise to the observed difference between the OPRs of IC 443 and HB 21, if dissociative J-shocks are responsible for the $H_2$ emission. Our study suggests that shocked-then-cooled $H_2$ gas may play as a heat reservoir with the non-equilibrium OPR.

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Study on the Simulation of Heat Pump Heating and Cooling Systems to Resident Building (숙박업소 건물의 히트펌프 냉난방 시스템 적용을 위한 시뮬레이션 연구)

  • Choi, Young-Don;Han, Seong-Ho;Cho, Sung-Hwan;Kim, Du-Sung;Um, Chul-Jun
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.1
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    • pp.65-74
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    • 2008
  • In Korea, air source heat pump system is less efficient than conventional heat source facilities, such as ground source, river water, because the air temperature in winter season is so low that COP of air source heat pump system drops below 3.0. Therefore, the study on the application of heat pump heating and cooling systems is crucial for the efficient popularization of heat pump. In this work, we present the dynamic analysis of energy consumption for the large resident building by heat resistance-capacitance method. The system simulation of water storage air source heat pump is additionally performed by changing of sizes and locations of the hospital building. The computed results show that energy cost of water storage air source heat pump is low, so it is more economical than absorption chiller & heater.