Developments in Thermal Pile and Thermal Tunnel Linings for City Scale GSHP systems

Abstract

The city scale development of horizontal trench closed loops and vertical borehole loops for ground source heat pump (GSHP) systems is limited by the lack of ground surface space. This paper discusses the use of thermal piles below city buildings. Consideration is given to the development of standards that maintain compatibility between the M&E, geothermal, and structural designs. The monitoring requirements are discussed. Cities also use tunnels to provide transportation and utility networks. Some of these tunnels must be cooled to meet operational requirements. This paper discusses the use of system-wide thermal tunnels with closed loops embedded in the tunnel segments. Water is circulated through the loops to cool the tunnels. The geothermal design of the loops and the impact on the structural performance is considered. The heat extracted from the tunnel is then used with GSHP systems to heat adjacent buildings via a district heating system. When planning a thermal tunnel system the future use of the heat for buildings must be investigated.