Modelling Thermal Interference and Impacts for Ground Source Heating and Cooling Systems

Abstract

Planning regulations introduced in the London boroughs around 2003 required all new buildings over 10,000 m2 to source 10% of their energy demand from renewable resources (‘renewables’). Ground source heating and cooling (GSHC) systems fall within the definition of renewables, and provide an effective means of meeting these regulations.

This paper provides an overview of numerical and analytical modelling techniques that have been used to evaluate the potential for thermal interference between open loop Ground Source Heating and Cooling (GSHC) system’s injection -abstraction well couplets. Thermal interference between individual well couplets is a key risk for sites where small development footprints limit the spacing between injection and abstraction wells. Assessment of the potential for thermal impacts on other groundwater users is also discussed.

A model validation study has been undertaken to evaluate the accuracy with which thermal interference can be predicted for a GSHC system in a fractured aquifer system, using a relatively limited dataset and simple fracture model. Results indicate that an acceptable level of accuracy is achievable.