An inquiry of ground heat storage: Analysis of experimental measurements and optimization of system’s performance
Publication date: 5 February 2019
Source: Applied Thermal Engineering, Volume 148
Author(s): Hafiz M.K.U. Haq, Erkki Hiltunen
One of the imminent challenges in Europe is to increase the use of decentralized energy production with or without backup from the main grid. Heat demand in Europe during winter is evidently higher than the rest of the year. With the development in the fields of solar thermal collectors and ground heat storage system, decentralized energy production enables net zero building implementation. This study investigates thermal response of a ground heat storage system over two consecutive charging period from June 2016 till August 2017. Heat energy (collected from solar collectors) is injected in the ground heat storage during summer season. Experimental measurements are presented in the study. Strategy of charging heat storage is proposed in order to conduct an optimal operation. The collected charging temperature (input signal) and initial conditions are applied in the model and results indicate that temperature of the ground rose from 8 °C to 18 °C within a period of one year. Temperature distribution of ground heat storage is predicted to be 24 °C over five-year period of operation. Thermal response of the ground heat storage is predicted between 18 °C and 34 °C over one-year period with variations in the injection power from 30 kW to 60 kW. Multi-year heat transfer in a standard Finnish soil is estimated to an average of 1.2 GJ.