Performance of Heat Pump System Using Underground Air as Heat Source

지하공기를 이용하는 농업시설용 난방시스템

  • 강연구 (농촌진흥청 에너지환경공학과) ;
  • 유영선 (농촌진흥청 에너지환경공학과) ;
  • 김영화 (농촌진흥청 에너지환경공학과) ;
  • 성문석 (제주도농업기술원 원예연구팀) ;
  • 김종구 (농촌진흥청 에너지환경공학과) ;
  • 장재경 (농촌진흥청 에너지환경공학과) ;
  • 이형모 (농촌진흥청 에너지환경공학과)
  • Published : 2009.11.25

Abstract

The districts of underground geologic structure in Jeju island where underground air is distributed are lava cave, pyroclastic, open joint, and crushing zone. Such districts are identified to secure an enough airflow when air ventilation layer is to secure 25-35m in depth. In Jeju, Ground air is used for heating greenhouse and fertilizing natural $CO_2$ gas by suppling directly into greenhouse. But the heating method by suppling ground air into greenhouse directly bring about several problem. The occurrence of disease of the crops by high humidity is worried because the underground air which becomes discharge from underground air layer has over 90% relative humidity. The underground air is inadequate in heating for crops which need high temperature heating such as mangos, Hallbong and mandarin orange because the temperature of it is $15{\sim}18^{\circ}C$. Also There is worry where the ventilation loss becomes larger because the air pressure inside greenhouse is high by supplying underground air directly. In this study the heat pump system using underground air as heat source was developed and heating performance of the system was analysed. Heating COP of the system was 2.5~5.0 and rejecting heat into greenhouse and extracting heat from underground air were 40,000~27,000 kcal/h, 30,000~18,000 kcal/h respectively.

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