Akademik Veri Yönetim Sistemi
1st International Conference on Energy Geotechnics (ICEGT), Kiel, Almanya, 29 - 31 Ağustos 2016, ss.513-520, (Tam Metin Bildiri)
Existing analytical solutions for thermal analysis of closed-loop ground heat exchangers systems evaluate temperature change in the heat carrier-fluid and the surrounding ground in the production period of Borehole Heat Exchangers (BHE) only if a continuous heat load is assigned. In the present study, we solve analytically the heat conduction/advection/dispersion equation in porous media, for intermittent heat extraction. We convolute rectangular function or pulses in time domain both for single and multi-BHEs field. The solution includes non-symmetric configurations around the BHEs by considering anisotropic features induced by groundwater convection or intrinsic anisotropy of thermal conductivity. Thermal dispersivity linked to the ground water flow is also considered. The validity of the analytical model is checked through the comparison with results obtained from numerical finite element code. The comparison results agree well with numerical results both for conduction and advection dominated heat transfer systems, and analytical solutions provide significantly shorter runtime compared to numerical simulations. The developed tool allows also to investigate the recovery aspects and the sustainability of closed-loop ground heat exchangers systems in terms of temperature and the energy deficit of the ground.