Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.1016/j.enbuild.2026.117612 |
Licence  |
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| Title (Primary) | Impact of load dynamics on ground source heat pumps connected to borehole heat exchanger fields |
| Author | Jaeschke, M.; Shao, H.
; Bucher, A. |
| Source Titel | Energy and Buildings |
| Year | 2026 |
| Department | ENVINF |
| Volume | 365 |
| Page From | art. 117612 |
| Language | englisch |
| Topic | T5 Future Landscapes T8 Georesources |
| Keywords | GSHP; BHE; OpenGeoSys; Building thermal energy |
| Abstract | Ground source heat pump (GSHP) systems coupled with borehole heat exchanger (BHE) arrays are an increasingly important technology for low-carbon heating and cooling of buildings. The design of BHE arrays depends critically on the building thermal load, yet in practice only annual or monthly energy demands are often available, and detailed hourly load profiles are rarely used. This study investigates how the temporal resolution of the building thermal load affects the design-relevant fluid temperatures in BHE arrays and assesses whether simplified load representations are sufficient for reliable system design. An open-source simulation workflow is developed that couples dynamic building energy modeling in OpenModelica with finite element subsurface heat transport simulation in OpenGeoSys. Three levels of load resolution are compared: hourly profiles from building simulation, daily and monthly constant loads obtained by time-integration of the hourly data. Simulations are conducted for 180 combinations of building type, construction year, and weather conditions, using thirty test reference year datasets from five locations across Germany. A load resampling method based on heating and cooling degree days is introduced to generate daily load profiles from annual energy demand alone. Results are further validated against a detailed co-simulation with a heterogeneous subsurface model and a physics-based heat pump model. The results show that reducing load resolution consistently raises the predicted minimum BHE fluid temperatures, with monthly constant loads overestimating the design-critical minimum temperature by up to 0.88 K relative to the hourly reference. Daily aggregation reduces this error to at most 0.11 K and is recommended as a practical minimum resolution for numerical BHE design. The study demonstrates that reliable BHE sizing requires consideration of not only the total annual energy demand but also its temporal distribution and load dynamics. The degree-day resampling method provides a simple way to incorporate load dynamics at the daily level when only annual demand data are available. |
| Jaeschke, M., Shao, H., Bucher, A. (2026): Impact of load dynamics on ground source heat pumps connected to borehole heat exchanger fields Energy Build. 365 , art. 117612 10.1016/j.enbuild.2026.117612 |
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