Making the most of temperature optimisation for sustainable district heating
Increasing energy efficiency through renewable energy solutions while minimising associated emissions is the main challenge to be resolved for the district heating (DH) industry. The reduction of operational temperatures in heating networks and the exploitation of renewable and excess heat as a heat source is a key approach in this direction. The EU-funded TEMPO project introduced six technological innovations that enable DH networks to operate at lower temperatures. Three of these come in digital form: an automated online supervision platform to detect faults in DH substations, visualisation tools for expert and non-expert users, and a smart DH network controller to optimise the supply and return temperatures. The other three constitute an innovative piping system, building installation optimisation and decentralised storage buffers. The TEMPO solution packages have been implemented, tested and evaluated at two demo sites: in Germany, in a new rural low-temperature DH network, and Italy, in an existing high-temperature DH network. Additionally, TEMPO proposed new business models and demonstrated their replication potential for the roll-out of sustainable and economically viable DH networks across the EU. “This has contributed substantially to the further development and deployment of DH networks in Austria, Flanders, Germany, Italy and at a European scale,” explains project coordinator Johan Desmedt.
Expanding European district energy control technology
One of the technologies developed and tested in the TEMPO project is a smart control system for the real-time operational optimisation of DH systems. This system builds upon work in the STORM project, during which a heat load control system for DH networks was developed using building demand response. In TEMPO, its scope was broadened towards operational optimisation of network temperature levels, both in the return and supply pipes. Since the return temperature is dependent on the customers, the controller optimises the return temperature through the management of the customers’ heat load. In contrast to STORM, where the thermal power profile was optimised, here the return temperature is minimised. The network supply temperature, however, is directly controllable on the production side. The network supply temperature can be lowered as close as possible to the limits determined by customer thermal demands. Moreover, the intrinsic thermal capacity of the piping can be activated to temporarily store heat and thereby shift the heat load in time by increasing the supply temperature of the network.
One step before the DH market
“Important lessons were learned in terms of processes for the future deployment and scaling of the TEMPO innovations – which enabled us to detect and diagnose suboptimal behaviour of specific building heating systems,” Desmedt says. “However, due to legal and organisational hurdles, in most cases it was not possible to share the information with the end consumers and carry out audits of the building installations to ascertain the cause, let alone to remediate the issues rapidly.” Successfully, the TEMPO solution packages could cover 90 % of the DH market and the main target groups are ICT companies with strong links to DH network operators. The team will soon develop and test future developments of the DH controller algorithm, in terms of market interaction, analytics features and more relevant factors. “The demonstration projects show not only the flexibility and adaptiveness but also the actual market demand for this type of technology,” concludes technical coordinator Dirk Vanhoudt.
Keywords
TEMPO, DH networks, return temperature, district heating, heat load, building installation, renewable energy, thermal capacity
