Long-term thermal performance analysis of a large-scale water pit thermal energy storage

Large-scale water pit thermal energy storage (PTES) promotes solar district heating (SDH) system as one of the most potential renewable applications for carbon neutrality. PTES needs vast investment and operates in a complicated with numerous components, highlighting need suitable simulation tool tech-economic feasibility investigations. This paper experimentally theoretically investigated long-term performance 60,000 m 3 Dronninglund, Denmark. Five years measurements were analyzed to investigate development temperatures, heat flows, stratification storage. A modified 2D model was proposed calculate large-scale based on XST TRNSYS. The results showed that developed predicts well temperatures flows. For one-year validation, deviations annual charged/discharged energy, internal content, loss between 2.0%/1.8%, 2.8% 1.3%, respectively. Dronninglund 90.1% efficiency five-year investigation due its high utilization cycle 2.16. Even without any insulation sidewall bottom PTES, average from two parts only accounted 32.3% total loss. Meanwhile, soil region needed four stabilize. Approx. 24.4% summer is regained by winter, when there low temperature findings serve good reference designers practitioners • 60000 theoretically. Annual obtained. Trnsys validated. Long term 5 consecutive years. Development around elucidated.