Fifth-generation DHC systems

Fifth-generation district heating systems distribute heat at even lower temperatures than 4GDH systems. This requires end users to boost temperatures using additional distributed heat pumps (Lund et al., 2021). Users can thus function as customers (by extracting heat from the network) or generators (by injecting heat into the network). The same principle applies for cooling.

5GDH, which is also known as a neutral loop, should not be seen as a sequential generational advancement over 4GDH, but as a variation of 4GDH or “sibling” (Lund et al., 2021). 5GDH is especially suitable for applications where cooling and heating demands are of similar size, making it an important innovation as the global cooling demand rises. ¹² 5GDH, which is also known as a neutral loop, should not be seen as a sequential generational advancement over 4GDH, but as a variation of 4GDH or “sibling” (Lund et al., 2021).

Fifth-generation systems use bi-directional pipes and a modern control and communications infrastructure (Figure 6.7) to allow users to consume or generate heat, or exchange it among themselves (E.ON, 2022; Kensa Heat Pumps, 2022). Meanwhile, the use of distributed heat pumps allows lower temperatures on the network, thereby reducing transmission heat losses and radically lowering the costs of installing distribution circuits.

FIGURE 6.7 Illustration of a fifth-generation DHC system

Fifth-generation systems can offer benefits beyond fourth-generation systems especially when the levels of heating and cooling demands are similar. They boost efficiency, encourage greater use of renewable sources and can lower overall costs.