Korean Journal of Air-Conditioning and Refrigeration Engineering (설비공학논문집)

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
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Sizing of Vertical Borehole Heat Exchangers using TRNOPT

TRNOPT를 이용한 수직 지중열교환기 길이 산정 방법에 관한 연구

  • Park, Seung-Hoon (Department of Architectural Engineering, Graduate school, Inha University) ;
  • Lee, Hyun-Soo (Department of Architectural Engineering, Graduate school, Inha University) ;
  • Jang, Young-Sung (GS E&C Building Science Research Team) ;
  • Kim, Eui-Jong (Department of Architectural Engineering, Inha University)
  • Received : 2016.08.01
  • Accepted : 2016.09.09
  • Published : 2016.10.10
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Abstract

Ground-coupled heat pump systems have been widely used, as they are regarded as a renewable energy source and ensure a high annual efficiency. Among the system components, borehole heat exchangers (BHE) play an important role in decreasing the entering water temperature (EWT) to heat pumps in the cooling season, and consequently improve the COP. The optimal sizing of the BHEs is crucial for a successful project. Other than the existing sizing methods, a simulation-based design tool is more applicable for modern complex geothermal systems, and it may also be useful since design and engineering works operate on the same platform. A simulation-based sizing method is proposed in this study using the well-known Duct STorage (DST) model in Trnsys. TRNOPT, the Trnsys optimization tool, is used to search for an optimal value of the length of BHEs under given ground loads and ground properties. The result shows that a maximum EWT of BHEs during a design period (10 years) successfully approaches the design EWT while providing an optimal BHE length. Compared to the existing design tool, very similar lengths are calculated by both methods with a small error of 1.07%.

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References

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