Fraunhofer simulates district heating management with a digital twin

06.01.2025

Source: E & M powernews

In the "AD Net Heat" project, Fraunhofer researchers are using new software to simulate heat flows in a network, forecast peak loads and help with the planning of new networks.

District heating networks are becoming increasingly complex due to the feed-in of renewable energies and the trend towards decentralization. Fraunhofer researchers have developed software that simulates heat flows in the entire network, forecasts peak loads and helps with the planning of new networks.

The model is the city of Ludwigshafen (Rhineland-Palatinate). The municipal utilities and heat suppliers are to convert their district heating networks to CO2-free operation in the coming years. However, fluctuations in the pipeline network caused by the feed-in of renewable energies and increasing decentralization make it difficult to control the networks efficiently.

With "AD Net Heat", Fraunhofer researchers have developed simulation software that simulates the heat flows in the grid. "This allows forecasts to be made in live operation about the heat flows and the demand at the consumption stations," explained Matthias Eimer from the Fraunhofer Institute for Industrial Mathematics ITWM. With this data, municipal utilities and energy suppliers can monitor and control the network with all its dynamics in real time. This makes the district heating network more stable overall and makes everyday operation more efficient and cost-effective.

District heating control in real time

The Fraunhofer researchers have developed a digital twin of the physical pipeline network in Ludwigshafen am Rhein. This incorporates basic data such as the topology of the network, the length and cross-section of the pipelines and the number and position of the feed-in points and consumption stations. In addition, factors such as weather data, solar radiation and the typical consumption profile at certain times of the day and year are taken into account.

The actual or planned feed-in data, such as the flow temperature or feed-in power, are also specified. On this basis, AD Net Heat simulates the dynamics of the entire network, provides parameters for points on the periphery of the network - the so-called bad points - and reports critical operating states. In addition, the control of the network can be optimized and fed back to the control station.

Only a few sensors required

By directly modeling the physical processes, the digital twin requires a minimal number of sensors. These are only used to calibrate unknown parameters, such as the pipe properties, which no longer correspond to the original condition due to ageing processes. Additional sensors can then be used to validate the simulation results.

The digital twin offers several advantages for operators of heating networks and municipal utilities: In many cases, optimized operation eliminates the need to switch on energy sources, which are currently very expensive as a result of electricity price fluctuations. In addition, the flow temperature, for example, can be lowered to reduce unnecessary energy losses - without jeopardizing the security of supply.

Major events in the city, such as a concert or trade fair, where large halls need to be supplied with heat, are also included in the operational planning. After entering the location of the customer and the estimated heat requirement, the software simulates the heat transport and returns its consumption forecasts.

Help with planning new networks

The software solution also helps with the planning and commissioning of new networks. Once the topology of a network has been defined, including the feed-in points for fluctuating energy sources such as solar thermal energy and industrial waste heat, the software tool calculates the distribution of heat flows and the expected consumption. Planning offices run through very different scenarios here, such as consumption at certain times of the day or year, different placement of generators or structural changes such as new transport lines.

"On the one hand, the simulation in the digital twin allows the maximum use of renewable energy sources when they are available," said Eimer. Secondly, the heat demand forecasts are very accurate and reliable. "This means that the cross-sections of the pipes can be designed slightly smaller, which saves material," says the scientist. The Fraunhofer researchers are currently working on making the user interface of AD Net Heat even simpler and clearer for users at heating suppliers and planning offices.

As the calculation core is basically designed for all network types, the simulation could also be used for energy networks such as electricity or gas in the future, the researchers explain.

Further information on the AD Net Heat simulation tool is available on the Internet.

Author: Susanne Harmsen