Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
649577 | Applied Thermal Engineering | 2008 | 10 Pages |
This study is performed to investigate the thermal performance of saturated soil around coaxial ground coupled heat exchanger (GCHE). Based on artificial glass micro-balls as porous medium, heat-transfer experiments are conducted. Then a theoretical model with Darcy’s natural convection is developed and some numerical solutions are obtained using Keller-Shooting method. There is a better coincidence between theoretical and experimental results, and theoretical model greatly reduces the limitations of experimental setup and reveals the heat-transfer performance within a wider range. The results indicate that heat transfer mainly happens near the outer wall of coaxial GCHE and inclines to stabilization at far-field. The inlet temperature, initial temperature of porous medium and the flow rate are major factors affecting heat transfer. Compared with operation mode II, the heat-transfer rate in operation mode I are higher for the same flow rate and initial temperature of porous medium. There is a linear relationship between dimensionless temperature gradient along the outer wall of GCHE and the dimensionless height.