Assessing the thermal efficiency of energy tunnels using numerical methods and Taguchi statistical approach

The use of ground source heat pump systems (GSHPs) with tunnels (so-called energy tunnels) to provide space heating and cooling is one the latest concepts that has recently raised research interest but not yet been commercially established. This study represents first attempt investigate influence design parameters on efficiency a GSHP using an underground tunnel as geostructure. Seven important parameters, namely absorber fluid diffusivity, concrete pipe thermal conductivity, diameter, length pipe, spacing location were considered. these was studied by experimentally validated 3-D numerical model then deploying Taguchi method efficiently explore space. results show diffusivity total are most influential followed while found be least factor. Hence overall output depends largely available area for exchange properties lining. Results also within range diameter considered, larger in more efficient from power requirements. These can used optimisation guidance both researchers practitioners.