Long-term Long Term Evaluation of Operation and Design of the Emmaboda BTES. : Operation and Experiences 2010-2015

The large-scale borehole layer (BTES) in Emmaboda was commissioned in 2010. Its aim was to make use of waste heat from the industrial processes at the Xylem plant. During all the years since its inception, additional heat sources have been included, and only now can the predicted annually amount of stored heat (3.6 GWh/year) be achieved. The average storage temperature is now 40-45oC. Very little of the injected heat has so been recovered (200 MWh) because the storage temperature was lower than expected. The reason for this is mainly that the amount of stored heat (12,000 MWh) is less than expected and that this heat also held a lower temperature than expected. Performed simulations based on actual storage data and presumed future operating data, show that the simulation model reasonably well predicts the future storage function. Initial circulation problems in the storage have been solved with the use of vacuum pumps for degassing of the liquid. The BTES has reduced the amount of annually purchased district heating by about 4 GWh. To further improve the system and reduce the heat losses, it is proposed to install a heat pump to heat withdrawal. This would enable the system to deliver high enough supply temperature for heating of the buildings. The system could then be operated according to planned annual heat injection/ extraction (3.6 GWh/2.7 GWh).Godkänd; 2016; 20160204 (bon)