this is the 36th issue of our heatbeat Research Newsletter, in which we give an update on recently published research on the topics of district heating, district cooling, and district energy systems. In this issue, we look at strategies to utilize waste heat, institutional inertia holding back progress, arial infrared thermography to estimate heat demands for cities, and the optimal scheduling of heat storages in district heating. And in addition, we share some video links and podcast recommendation featuring heatbeat with you.

Waste Heat Valorization Strategies for Integration into District Heating Networks?

On the one hand, integrating waste heat as a heat source into district heating is a very promising option for the decarbonization of the heating sector. On the other hand, the integration of waste heat is a very complex challenge, because the availibility and temperature level of waste heat varies from case to case. And furthermore, there are many technical options for the integration of waste heat into district heating, ranging from a direct network feed-in to utilizing the waste heat as the source for heat pumps which raise the temperature level at the cost of its electricity input. In this context, it is important to develop systematic strategies for utilizing a given waste heat potential to the greatest benefit of both the environment and the energy system. The paper "Valorisation of Waste Heat in Existing and Future District Heating Systems" by Pakere et al. is an important contribution to this topic.

In this paper, the authors evaluate various potential waste heat source, including for example heat from flue gases of biomass CHPs and boilers, the wood processing industry, data centers, and waste water treatment plants. And they consider different possible network setups into which such waste heat could be integrated, ranging from existing networks with rather high temperatures, to low-temperature district heating and even ultra-low-temperature district heating. For the example of Latvia, the authors show that the waste heat potential increases from around 1,800 GWh/a for high-temperature networks to around 3,400 GWh/a for low-temperature networks. At the same time, they raise the interesting question about how large the impact of ultra-low-temperature district heating will be in countries with already well-developed district heating infrastructure working at higher temperatures. And furthermore, an interesting finding of the study is that integrating waste heat also poses a challenge for already existing solar thermal heat in the same network. As waste heat is often also available during the summer with low heat demands in the network, this can result in competition for solar thermal plants which have their highest feed-in potential during this time. Thus, the paper recommends careful consideration of the local conditions when evaluating the best path to integrate waste heat into district heating.

Institutional Inertia in Real-World District Heating Experiments

When we talk about inertia in district heating from a technical perspective, we often consider the storage effects of the network medium and temperature wave propagations through the network. But beyond that technical view, the decarbonization of district heating also needs to overcome hesitation and slow progress. To better address these challenges, the paper "Too big to succeed? Institutional inertia in low-carbon district heating experiment" by Moilanen et al. explains the useful term of institutional inertia with an example of a real-world district heating experiment in Turku in Finland.

In this experiment, a district in the Skanssi area of Turku was to be supplied by a bi-directional low-temperature network, in which buildings and distributed green heat sources such as ground-source heat pumps and solar thermal could trade excess heat and thus meet their total demand most efficiently. The paper investigates which challenges prevented the experiment from being a full success so far and identifies the different institutional inertias of the various stakeholders holding back innovation. As a key finding, the paper shows that the collaboration between different actors in such an experiment needs to be prepared by a joint vision. If this is not the case, knowledge gaps between actors, temporal mismatches in the implementation, and undefined overall business cases can cause significant intertia and thus slow down the decarbonization of district heating.

Further Reading

In addition to the two papers mentioned above, we saw many other interesting papers being published recently. These include for example the paper "Aerial urban observation to enhance energy assessment and planning towards climate-neutrality: A pilot application to the city of Turin" by Anselmo et al. which demonstrates how aerial infrared thermography can be used to estimate the heat demand and reduction potential of a city's building stock efficiently. And the paper "Optimal scheduling of energy storage in district heating networks using nonlinear programming" takes a deeper look at how to optimize the storage usage in district heating in order to reduce the operating costs.

Some heatbeat News

And to conclude our newsletter, we want to share a few news and links about heatbeat with you: Back in June, we enjoyed participating in the Super Impact Day in Stuttgart. And we are happy, that now some interesting videos from this great event are available online. There's a video of the panel discussion on heat transformation including our CEO Peter. And in addition, we are grateful that NEW's presentation of our joint project Seestadt mg+ also includes an overview of our heatbeat Digital Twin.

Beyond that, if you want to hear more from us, we can recommend the podcast Utility 4.0 where Peter was invited for the latest episode to discuss the potential of digitalization for district heating in depth.

The next issue of our newsletter will be published on November 1, 2023.