Energy storage-integrated ground-source heat pumps for heating and cooling applications: A systematic review

Renewable energy-based ground source heat pump (GSHP) systems have gained traction as cost-effective and environmentally sustainable alternatives for heating and cooling applications in residential, commercial, and civic buildings. However, their prolonged operation may lead to a decline in the geothermal potential of the soil and its thermal imbalance. The integration of thermal energy storage (TES) systems with GSHPs can mitigate these issues by balancing energy supply and demand, providing flexibility to meet heating and cooling demand during peak hours, preserving energy during off-peak hours, and optimising overall system efficiency. In recent years, there has been a significant increase in experimental, numerical, and theoretical studies investigating various TES-assisted GSHP configurations under different operational conditions and climate scenarios. These integrated systems may consider different sensible heat, latent heat, and sensible-latent heat-based TES methods. In this context, this paper presents a comprehensive overview of recent progress in TES-assisted GSHP systems. The main objectives of this work are to bridge the knowledge gap on these integrated systems, provide clarity on the adopted terminology, and highlight advantages and disadvantages of the different configurations presented in the literature. This review is expected to offer valuable insight for researchers and partitioners in the field of TES-assisted GSHPs and guide future research and development efforts in the area—ultimately supporting the path towards decarbonisation of heat (including space cooling) and meeting net-zero targets.