Application of large underground seasonal thermal energy storage in district heating system: a model-based energy performance assessment of a pilot system in Chifeng, China

L. Xu, J.I. Torrens Galdiz, F. Guo, X. Yang, J.L.M. Hensen

Research output: Contribution to journalArticleAcademicpeer-review

11 Citations (Scopus)
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Abstract

Seasonal thermal energy storage (STES) technology is a proven solution to resolve the seasonal discrepancy between heating energy generation from renewables and building heating demands. This research focuses on the performance assessment of district heating (DH) systems powered by low-grade energy sources with large-scale, high temperature underground STES technology. A pilot DH system, located in Chifeng, China that integrates a 0.5 million m3 borehole thermal energy storage system, an on-site solar thermal plant and excess heat from a copper plant is presented. The research in this paper adopts a model-based approach using Modelica to analyze the energy performance of the STES for two district heating system configurations. Several performance indicators such as the extraction heat, the injection heat and the storage coefficient are selected to assess the STES system performance. Results show that a lower STES discharge temperature leads to a better energy performance. A sensitivity analysis of the site properties illustrates that the thermal conductivity of soil is the most influential parameter on the STES system performance. The long-term performance of the STES is also discussed and a shorter stabilization time between one and two years could be achieved by discharging the STES at a lower temperature.

Original languageEnglish
Pages (from-to)319-328
Number of pages10
JournalApplied Thermal Engineering
Volume137
DOIs
Publication statusPublished - Mar 2018

Keywords

  • Building performance simulation
  • District heating
  • Industrial waste heat
  • Modelica
  • Seasonal thermal energy storage
  • Solar thermal collectors

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