DESIGN AND PERFORMANCE ANALISYS OF SLINKY^TM TYPE FOUNDATION HEAT EXCHANGERS FOR SPACE HEATING AND COOLING IN A COLD CLIMATE

Among the renewable energy technologies, ground source heat pumps (GSHP) offer a sustainable and efficient performance and have gained attraction for space heating and cooling. However, the high cost of the drilling and heat exchanger installation can dim this appeal and hinder their widespread usage. Unlike the vertical counterparts, the horizontal ground heat exchanger (HGHX) avoids the high drilling cost as it can be laid in shallow trenches. Moreover, their installation cost can be reduced by integrating them into the building foundation. Slinky^TM configurations have been popular thanks to their ease of installation, the flexibility of design parameters, and less land requirement due to high pipe density. Although they have been around for more than decades, their analysis is still challenging due to their complicated geometry compared to horizontal, vertical, and even helical configurations. Many studies have focused on studying a few numbers of coils or simplifying the geometry to an array of ring sources to accommodate analytical solutions. Consequently, they fail to precisely capture the thermal interaction between the loops. Moreover, the performance of such foundation heat exchangers coupled with the GSHP has not been studied sufficiently. This work numerically investigates the long-term performance of arrays of slinky heat exchangers integrated into the foundation of a residential building in a heating-dominated climate. Moreover, the impact of design and operational parameters such as the HGHX compactness, depth, and inlet velocity are explored.