• Title/Summary/Keyword: 비제습률

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Drying Performance Simulation for the Basic Design of a Heat Pump Dryer (열펌프 건조기의 기본 설계를 위한 건조 성능 해석)

  • Lee, Kong-Roon;Kim, Ook-Joong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.10
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    • pp.860-867
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    • 2007
  • Heat pump drying has a great potential for energy saving due to its high energy efficiency in comparison with conventional air drying. In the present study, the performance simulation for the basic design of a heat pump dryer has been carried out. The simulation includes one-stage heat pump cycle, simple drying process using the drying efficiency. As an example, the heat pump cycle with Refrigerant 134a has been investigated. For the operating conditions such as the average temperature of the condenser, the heat rate released in the condenser, the flow rate of drying air, and drying efficiency, the simulation has been carried out to figure out the performance of the dryer. The parameters considered in the design of the dryer are COP, MER, SMER, the rate of dehumidification, the temperature and humidity of drying air and those parameters are compared for different conditions after carrying out the simulation.

Investigation of Experimental Results Using the Drying Model for a Heat Pump Dryer (열펌프 건조 해석 모델을 이용한 측정 결과의 분석)

  • Lee, Kong-Hoon;Kim, Ook-Joong;Kim, Jong-Ryul;Lee, Sang-Ryoul
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2268-2273
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    • 2008
  • The drying model has been used to obtain the fundamental information required to design the heat pump dryer with the simple thermodynamic model. In the model, the input conditions are crucial to obtain the acceptable results. The model includes one-stage heat pump cycle, simple drying process using the drying efficiency. The drying efficiency is defined with the conditions of inlet and outlet in the dryer. The experiment has been carried out in the pilot dryer with one-stage heat pump cycle. Refrigerant 134a is used in the heat pump cycle. In the dryer, some of drying air flows through the heat pump system and the rest of air bypasses the heat pump system and circulates through the drying chamber. Some operating conditions from the pilot dryer are used as input conditions of the model and the results are compared with experimental results for the validation.

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Analysis on the Drying Performance with the Flow Rate of Circulation Air in a Heat Pump Dryer (순환 공기 유량의 변화를 고려한 열펌프 건조기의 성능 해석)

  • Lee, Kong-Hoon;Kim, Oak-Joong;Lee, Sang-Ryoul
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.21 no.1
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    • pp.1-8
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    • 2009
  • The simulation of a heat pump dryer has been carried out to figure out the effect of air flow rate on the drying performance represented by MER, SMER, and so on. The simulation includes the analyses of one-stage heat pump cycle and simple drying process using the drying efficiency. The heat pump cycle with Refrigerant 134a has been considered. In the dryer, some of drying air from the drying chamber flows through the heat pump system, the rest of air bypasses the heat pump system. The two air flows joins before the drying chamber inlet. The performance parameters considered in the present study are MER, SMER, the temperature and humidity of drying air. Those parameters are compared for different total air flow rate or bypass air flow rate.

Energy Performance Analysis of Electric Heater and Heat Pump Food Dryers (전기히터식 및 히트펌프식 식품 건조기의 에너지 성능 비교)

  • Yu, Young Woo;Kim, Young Il;Park, Seungtae
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.11 no.4
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    • pp.1-6
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    • 2015
  • In this study, energy performance of two types of food dryers which are electric heater and heat pump is studied experimentally. With drying chamber temperatures controlled at 45, 50 and $55^{\circ}C$, sliced radish is dried from an initial mass of 90 to final 7 kg. Moisture content, drying time, total power consumption, MER (moisture extraction rate, kg/h) and SMER (specific moisture extraction rate, kg/kWh) are measured and analyzed. As the drying chamber temperature is increased, drying time is shortened but energy efficiency is reduced for both types. For an electric heater dryer, the effect of chamber temperature on drying time is significant but less significant on energy efficiency. For a heat pump dryer, the dependence of chamber temperature on drying time is weak but strong on energy efficiency. Temperature levels have little effect on electric heater dryer performance but strong effect on heat pump dryer which operates on a vapor compression refrigeration cycle. The energy performance of the heat pump dryer is superior with an average SMER of 2.175 kg/kWh which is 2.22 times greater than that of the electric heater dryer with SMER of 1.224 kg/kWh.

Energy Performance Comparison of Electric Heater and Geothermal Source Heat Pump type Agricultural Hot Air Dryers (전기히터식 및 지열원 히트펌프식 농산물 열풍건조기의 에너지 성능 비교)

  • Yang, Won Suk;Kim, Young Il;Park, Seung Tae
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.14 no.4
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    • pp.7-12
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    • 2018
  • Energy performance of electric heater and geothermal source heat pump type hot air dryers are compared in this study. For set temperatures of $30^{\circ}C$, $35^{\circ}C$ and $40^{\circ}C$, radish is dried from initial mass 60 kg until it gets 5 kg, where the difference equals the amount of water removed. As set temperature is increased, drying time is shortened for both electric heater and heat pump types, however energy efficiency is decreased due to increasing electricity consumption. Moisture extraction rate(MER) of electric heater is 2.58~2.84 kg/h, and for heat pump type 2.56~2.71 kg/h, showing little difference between the two types. Specific moisture extraction rate (SMER) of electric heater is 0.94~0.96 kg/kWh, and for heat pump type 1.72~2.21 kg/kWh. SMER of heat pump type is greater by 0.78~1.25 kg/kWh than the electric heater hot air dryer, which is 1.8~2.3 times better in terms of energy efficiency.

Development of Decompressed Dryer for Mushroom (버섯의 감압건조기 개발)

  • 김영민;김유호;조영길;최희석;조광환
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2003.07a
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    • pp.267-272
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    • 2003
  • 본 연구에서는 버섯의 건조시간을 줄여 건조 후 버섯의 품질을 향상시키기 위하여 버섯의 감압건조기를 개발하였으며 연구 결과는 다음과 같다. 가. 버섯의 감압건조기의 시작기를 제작하였고, 시작기의 구조는 건조실, 감압블로워, 흡ㆍ배기구 솔레노이드 밸브, 제습장치, 송풍기, 전기히터로 구성되어 있으며, 건조실의 내부 압력이 표준대기압-900hPa, 열풍온도는 상온에서 5$0^{\circ}C$까지 조절할 수 있도록 제작하였다. 나. 시작기를 이용하여 표고버섯을 대상으로 건조특성시험을 실시한 결과, 열풍온도 5$0^{\circ}C$, 건조실 내부압력 900-940hPa에서 건조시간은 11.5h으로 대기압과 비교하여 6.5h 단축되는 것으로 나타났다. 또한, 건조 전ㆍ후의 색차, 수축률, 복원률의 품위가 우수한 것으로 나타났으며 F-test 유의성 검증 결과, 5%의 유의수준에서 갓주름의 색차, 갓직경의 수축률, 복원률에서 유의차가 있는 것으로 나타났다. 다. 열풍온도 5$0^{\circ}C$, 건조실 내부압력 900-940hPa로 표고버섯과 아가리쿠스에 대하여 건조성능시험을 실시한 결과, 표고버섯의 경우 건조시간은 13h으로 열풍식 농산물 건조기와 비교하여 건조시간이 4.5h 단축되는 것으로 나타났으며, 아가리쿠스의 경우 건조시간이 17.5h로 나타났다. 라. 성능시험 결과, 시작기가 열풍식 농산물건조기와 비교하여 건감률, 색택, 수축률, 복원률 등의 품위가 전반적으로 우수한 것으로 나타났다. 마. 시작기의 건조비용을 분석한 결과, 건조시간은 단축되었지만 시설투자비가 높아 건조비용이 표고버섯의 경우 2,461원/kg으로 열풍식 농산물건조기 보다 13% 높은 것으로 나타났지만, 추후 고품질 건조버섯 생산을 위한 기초자료로 활용이 가능할 것으로 판단된다.라갈수록 낮은 온도분포를 나타내고 있는 것은 상부에는 외부공기가 유입되면서 온도가 떨어지는 반면 하부에는 외부공기 유입이 적기 때문으로 사료된다. 또한 열풍실의 길이방향 위치별 온도 분포에서도 같은 현상으로 나타났고, 버너쪽과 송풍기쪽의 온도편차는 나타나지 않아 균일 건조를 기대할 수 있다. 마. 열풍온도를 45$^{\circ}C$로 설정하고 조사거리와 방사체 길이를 각각 119, 1,470mm로 하여 벼의 건조성능시험을 열풍건조기(대비구)와 비교시험 결과 시험구에서 건감률, 건조소요에너지가 각각 0.58%(w.b.), 470kcal/kg - water로 대비구보다 각각 건감율은 23% 높았고, 건조소요에너지는 2%의 절감되었다. 바. 건조기에서 발생되는 소음은 버너쪽 근처에서는 대비구 94.12㏈의 87%에 불과하였으나, 거리가 멀어질수록 차이는 크지 않았다. 이것은 버너에서 멀어질수록 외부적인 요인이 소음에 영향을 미쳤기 때문인 것으로 생각된다. 사. 시작기와 대비구간의 경제성에서 시작기의 구입가격이 20% 비싸기 때문에 시간당 고정비가 높았으나, 건조성능이 우수하여 건조비용이 69,350원/톤으로 대비구보다 14% 절감되는 것으로 나타났다.작용하는 것으로 사료된다.된다.정량 분석한 결과이다. 시편의 조성은 33.6 at% U, 66.4 at% O의 결과를 얻었다. 산화물 핵연료의 표면 관찰 및 정량 분석 시험시 시편 표면을 전도성 물질로 증착시키지 않고, Silver Paint 에 시편을 접착하는 방법으로도 만족한 시험 결과를 얻을 수 있었다.째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰 자기폭풍일수록 현저했다. 주상에서 관측된 이러한 특성은 서브스톰 확장기 활동이 자기폭풍의 발달과 밀접한 관계가 있음을 시사한다.se that were all

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A Study on Optimizing Drying Performance of Air Dryer (에어 드라이어 제습성능 최적화 프로그램 개발)

  • Park, Won-Ki;Lee, Hi-Koan;Yang, Gyun-Eui;Mun, Sang-Don
    • Transactions of the Korean Society of Automotive Engineers
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    • v.18 no.6
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    • pp.70-75
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    • 2010
  • Compressed air represents an energy source and an force-transmission medium for brake systems on medium-heavy and heavy-duty commercial vehicles. However, one disadvantage is the tendency of air to absorb moisture in the form of water vapor. This water vapor condenses once the air, which is heated during compression, cools back to ambient temperature upon emerging from the air compressor. The resulting condensation assumes the form of moisture in pneumatic lines, air tanks, cylinders and valve assemblies and can have negative consequences for the brake system and vehicle safety. The pneumatic systems on today's vehicles are equipped with air dryers, in which the supplied air is dried according to the adsorption principle. In the systems, the compressed air flows through a granular desiccant with molecular sieves which captures the water molecules.

A study on the Development of Automatic Drying System of Ginseng (인삼의 자동건조시스템 개발에 관한 연구)

  • Kang, Hyun-Ah;Chang, Kyu-Seob;Chang, Dong-Il
    • Korean Journal of Food Science and Technology
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    • v.25 no.6
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    • pp.764-768
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    • 1993
  • This study was developed a computer-controlled automatic drying system. In order to control automatically the temperature, relative humidity weight of the sample, drying system with computer and connecting parts such as microcomputer, PC-Lab card, Op. Amp., and relay system were developed for controlling the heater, fan, humidifier and dehumidifier. Using this system, drying characteristic mechanism of ginseng were investigated. The increase of drying temperature decreased Hunter L value and increased a and b value. The hardness and shrinkage rate of white ginseng had a increasing tendency with the increase of drying temperature. Crude saponin content was not affected by drying temperature and relative humidity.

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