Design of High-Performing Hybrid Ground Source Heat Pump (GSHP) System in an Educational Building

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
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Buildings, Volume 13, issue 7
Underground thermal imbalance poses a challenge to the sustainability of ground source heat pump systems. Designing hybrid GSHP systems with a back-up energy source offers a potential way to address underground thermal imbalance and maintain system performance. This study aims to investigate different methods, including adjusting indoor heating and cooling setpoints and dimensioning air handling unit (AHU) cooling coils, heat pump and borehole field, for improving the long-term performance of a hybrid GSHP system coupled to district heating and an air-cooled chiller. The system performance, life cycle cost and CO2 emissions were analyzed based on 25-year simulations in IDA ICE 4.8. The results showed studied methods can significantly improve the hybrid GSHP system performance. By increasing the AHU cooling water temperature level and decreasing indoor heating and cooling setpoints, the ground thermal imbalance ratio was reduced by 12 percentage points, and the minimum borehole outlet brine temperature was increased by 3 °C in the last year. However, ensuring long-term operation still required a reduction in GSHP capacity or an increase in the total borehole length. The studied methods had varying effects on the total CO2 emissions, while insignificantly affecting the life cycle cost of the hybrid GSHP system.
| openaire: EC/H2020/856602/EU//FINEST TWINS Funding Information: This research was funded by China Scholarship Council, Grant No. 202006370019. The research also received further funding from FINEST Twins project which is co-funded by the European Union (Horizon 2020 Program, Grant No. 856602) and the Estonian government. Publisher Copyright: © 2023 by the authors.
borehole free cooling, district heating, hybrid ground source heat pump, long-term performance analysis
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Xue, T, Jokisalo, J, Kosonen, R & Ju, Y 2023, ' Design of High-Performing Hybrid Ground Source Heat Pump (GSHP) System in an Educational Building ', Buildings, vol. 13, no. 7, 1825 .