Journal of the Korean Society for Geothermal and Hydrothermal Energy (한국지열·수열에너지학회논문집)

Korean Society for Geothermal and Hydrothermal Energy (한국지열·수열에너지학회)
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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 (Graduate School, Seoul National University of Science and Technology) ;
  • Kim, Young Il (School of Architecture, Seoul National University of Science and Technology) ;
  • Park, Seung Tae (ATENG)
  • 양원석 (서울과학기술대학교 일반대학원) ;
  • 김영일 (서울과학기술대학교 건축학부) ;
  • 박승태 ((주)에이티이엔지 기술연구소)
  • Received : 2018.08.28
  • Accepted : 2018.11.22
  • Published : 2018.12.01
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Abstract

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.

Keywords

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Fig. 1. Hot air dryer for testing both electric heater and geothermal source heat pump.

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Fig. 2. Electric heater, heat pump type hot air dryer diagram.

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Fig. 3. Geothermal source heat pump performance data.

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Fig. 4. Measured power consumption and mass.

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Fig. 5. SMER and MER.

Table 1. Hot air dryer specification

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Table 2. Heat pump hot air dryer underground heat exchanger and underground specification

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Table 3. Drying test results of electric heat and geothermal source heat pump type hot air dryers

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References

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