HEAT TRANSPORT IN LOW-TEMPERATURE GEOTHERMAL ENERGY DEVELOPMENTS

The use of temperatures to track groundwater flow has grown in popularity in many applications over the past decade. Despite our growing knowledge on this subject, there has been a reluctance to consider advection in the design of low-temperature geothermal developments. Few of these developments have installed monitoring wells or conducted post-audits to assess whether groundwater flow has impacted system operation. Efforts to determine the effect of groundwater flow on these systems has come from modelling, field experiments and natural analogs. Based on these efforts, it appears that groundwater flow is an important consideration where groundwater flow excess 10^-8 m/s. This is consistent with other efforts to use heat flow as a groundwater tracer. In such instances, ignoring advection an result in over design of systems. Where the intent of a system is to store heat, groundwater flow could make this infeasible. Use of simple screening methods should allow for delineation of areas where groundwater will effect low-temperature geothermal systems.