Design and cost comparison of district heating and cooling (DHC) network configurations using ring topology-A case study

District heating systems are evolved from steam systems (1st generation) to low temperature water based systems (4th generation) and pilot projects are coming out on ultra-low temperature systems along with building side heat pumps (5th generation). Some of the notable features of future (4th and 5th generation) district heating and cooling (DHC) networks are the integration of distributed low-temperature sources, combined DHC systems, integrated heat and cold storage, and usage of heat pumps at building side. The design of large-scale DHC networks with all these features poses many challenges. In this paper, a method to design 3-pipe DHC networks and ultra-low temperature DHC networks using a ring network configuration will be described and their network costs are compared. The developed method is implemented as a proof of concept in the DHC design tool, Comsof Heat and a case study is developed to design and compare these two configurations and study the effect on the network cost. Based on the case study results, the network deployment cost of ultra-low temperature DHC ring networks is around 23% costlier than the 3rd generation ring networks. Moreover, the ultra-low temperature (5th generation) networks are economically attractive only if there is a free low temperature waste heat source.

Automated summary

District heating systems are evolving from steam systems to ultra-low temperature systems. Future district heating and cooling networks will integrate low-temperature sources, combined DHC systems, heat and cold storage, and heat pumps at building side. Designing large-scale DHC networks with these features is challenging.