Figure 5.
The image shows a three-dimensional cutaway of an urban area with surface buildings and underground infrastructure connected by an ultra-low temperature or ambient loop heat network. At ground level, residential buildings, apartments, roads, and an energy centre connect to a shared heat network. A single building ground source heat pump system links into the network. Below ground, a tunnel heat source captures heat from a rail tunnel, with a ventilation shaft connecting the tunnel to the surface pipework. A station heat source recovers heat from an underground station space. Coloured pipes show heat flow between tunnels, stations, buildings, and the energy centre through the ambient loop heat network.Tunnel energy system with different supply options