Work Item B.4 of Subtask B in IEA EBC Annex 84 explores how monitoring, sensing, and control technologies can enable demand response (DR) and improve the performance of district heating and cooling (DHC) sys-tems. As DHC networks evolve toward low-temperature operation for decarbonization, accurate and real-time data from buildings and substations becomes essential to unlock flexibility and system optimization.

The report begins by examining the current status of sensors and monitoring systems within DHC networks. While production and distribution systems are typically well-monitored, building-level substations often lack sufficient instrumentation. This deficiency hampers proactive fault detection and contributes to inefficiencies such as high return temperatures. Incorporating standardized sensor sets—including temperature, pressure, flow, and energy meters—enables smarter control and better system diagnostics.

The study highlights the challenges and opportunities presented by digitalization. Key opportunities include the integration of IoT devices, smart meters, and AI/ML algorithms to enable predictive maintenance, dy-namic heat control, and user feedback. However, challenges remain in managing large volumes of data, ensuring interoperability across devices and platforms, and maintaining data privacy and cybersecurity. Reg-ulatory hurdles and varying technical standards also add complexity across different regions.

A major focus is the required sensor technologies for effective DR at the building level. Examples include heat cost allocators, electronic radiator thermostats with return temperature control, and smart IoT-enabled devices such as room temperature collectors and balance valves. These technologies not only support real-time monitoring but also allow decentralized control strategies that enhance energy efficiency and user com-fort.

The report also maps the architecture of IoT systems, breaking them into five functional layers (perception, network, middleware, application, and business) and discussing the key communication protocols (e.g., MQTT, CoAP, LoRaWAN, OPC UA). It emphasizes that IoT-enabled smart control infrastructure allows for dynamic energy management, remote diagnostics, and the scaling of DR strategies across diverse building types.

In conclusion, Work Item B.4 presents a compelling case for modernizing DHC networks through smart sens-ing and control. It offers insights into current technologies, identifies gaps and limitations, and outlines path-ways for future integration—ultimately paving the way for more flexible, efficient, and user-centric district heating systems.

Work Item B.2 under Subtask B of the IEA EBC Annex 84 explores innovative technologies that enable demand response (DR) and flexibility at the building level, focusing on the supply, storage, and distribution of thermal energy and electricity. The objective is to identify, assess, and document technologies and strat-egies that can improve energy efficiency, support sustainability goals, and facilitate integration with district heating and cooling (DHC) systems.

The report concentrates on four main activities:

1. Collection of case studies and best practices

Real-world demonstrations and research projects were gathered across three key domains: supply, storage, and distribution. These examples provide insights into technical and economic performance and the feasibility of DR in buildings connected to DHC networks.

2. Evaluation of storage technologies

Emphasis was placed on less mature technologies (TRL <6), such as phase change materials (PCM), for their potential to store thermal energy and shift demand. A highlighted case study from South Korea demonstrated a 59.9% reduction in peak load deviation through latent heat storage integration in apart-ment buildings.

3. Assessment of distribution technologies

Technologies such as decentralized substations, smart heat interface units (HIUs), and hydronic radia-tors were evaluated. Smart HIUs showed the ability to lower system temperatures and enhance DR potential, while field tests of hydronic radiators in Denmark demonstrated successful room-level load shifting.

4. Analysis of supply technologies

Innovations like electric resistance heaters (as Power-to-Heat systems) and control solutions like the PreHeat system were studied. Electric boosters proved capable of reducing peak loads by up to 48%, and control solutions yielded up to 20% energy savings in monitored buildings.

The report emphasizes that while many high-TRL technologies are already deployed and well-documented, the real value lies in examining novel, field-tested solutions with strong links to control strategies and cross-sector integration. Technologies enabling real-time response to grid signals—supported by Internet of Things (IoT), smart metering, and advanced control algorithms—are pivotal in making buildings active participants in energy flexibility markets.

Overall, Work Item B.2 provides a comprehensive foundation for advancing energy flexibility at the building level, aligning building operation with broader energy system needs through smart thermal and electrical integration.

In the pursuit of more sustainable energy practices, a closer look at the interplay between building typologies and district heating and cooling systems in Europe reveals a complex landscape. This examination emerges from the activities planned under the STB1 initiative, focusing on analyzing heating and cooling systems, reviewing connected buildings, deriving specifics for building types, and evaluating technical options for thermal storage and demand response.

A total of 29 case studies from various research projects have been collected as part of Subtask D of IEA EBC Annex 84, “Demand Management of Buildings in Thermal Networks”

This presentation provides a standardized and categorized summary of each case study,offering valuable insights into different approaches, technologies, and strategies for optimizing demand management in thermal networks.

Slides 2–7 explain the information presented.

Slides 8–10 offer the tables of contents and an overview of all published case studies.

The ongoing digitalisation of the district heating sector, particularly the installation of smart heat meters (SHMs), is generating data with unprecedented extent and temporal resolution. This data offers potential insights into heat energy use at a large scale, supporting policymakers and district heating utility companies in transforming the building sector. Clustering is crucial for representing this wealth of data in human-understandable groups, necessitating consideration of seasonality.

Advancing current research in clustering SHM data, this work applies an established co-clustering approach, FunLBM, considering seasonal variation without fixed season definitions. Furthermore, to enhance the understanding of differentiating factors between clusters, the possibility to understand cluster memberships based on 26 building characteristics was analysed using classification and variable selection methods.

Applying FunLBM on a large-scale hourly dataset from single-family houses revealed six well-separated energy use clusters each distributed over six-temporal clusters, which are correlated with the exterior temperature, yet not following fixed seasons. Variable selection and classification showed that building characteristics describing the building with a high level of detail are insufficient to explain cluster membership (Matthew’s correlation coefficient (MCC) ~0.3).

By merging the energy use clusters based on profile and magnitude similarities, classification performance significantly improved (MCC ~¨0.5). In both cases, simple and readily available building characteristics yield similar insights to detailed ones, emphasising their cost-effectiveness and practicality.

Buildings connected to district heating and cooling (DHC) networks are equipped with a heating/cooling sub-station, where the hot/cold district water loop interfaces with the building’s heating/cooling and domestic hot water (DHW) loops. These in-house substations play a crucial role in supplying thermal energy in line with building demand. They are designed to transfer heat from the (primary) DHC system to the (secondary) building energy system, ensuring the required supply water temperature, pressure, and mass flow to meet the thermal and DHW comfort needs of end-users.

To date, the primary focus of DHC operators has been to secure supply of heat/cold at a maximum temper-ature difference (delta T), in order to minimize mass flow rates and hydraulic effort in the DHC system. Flex-ible operation of substations – considering load management and demand response – has not traditionally been a priority for either DHC or building operators. However, to unlock thermal flexibility at the building level (e.g., through thermal storage capacity or variation in supply and return temperatures) while maintaining end-user comfort, building systems must evolve. This includes enabling third-party access, implementing auto-mated fault detection and remediation, and introducing demand management at the building level.

This report focuses on the following research questions:

• What is the typical equipment used in the most common DHC substations today?


• Are there significant differences across countries, and what are they? This includes national best prac-tices, technical specifications, standards, guidelines, and legal framework.


• Based on the above, what are the minimum design requirements for a DHC substation, and which com-ponents are most commonly used?


• What thermal flexibility potential can be provided by these components?


• What is the flexibility readiness status of a typical DHC substation, and how can it be quantified?

In summary, this document provides an overview of current practices in DHC systems, with a special focus on the role of substations. It serves as a reference and starting point for future demand-side management initiatives, offering insights into where flexibility potential

The transition to smart and decarbonized energy systems calls for active involvement from all energy sectors. To meet the conditions of the 2015 Paris Agreement, the entire energy supply chain, encompassing production, distribution, and consumption, must contribute and collaborate. In the recent energy crisis, resilience and Demand Response (DR) in the District Heating (DH) systems have gained international interest.

Although numerous simulation studies and a few demonstrations, conducted in controlled real-life environments, have documented the potential benefits of DR, there is still limited understanding of the approach DH professionals take toward DR.

This work presents the results of a 17-question survey conducted with DH professionals in seven European countries (Austria, Denmark, Germany, France, Italy, and Switzerland) to gain insights into the existing practices, rationalities, barriers, legal framework and needed developments for the large-scale roll-out of DR in the DH sector.

In total 30 responses were collected. The results show, that DH professionals lack clear evidence of the advantage of distributed storage over centralized solutions. Control, ownership, responsibilities, and security are the topics that hinder the use of DR in everyday operation of DH systems. Moreover, there is a lack of business models for how to price the customers for delivered flexibility. The lack of a well-formulated and clear legal framework is also an additional obstacle.

Contribution to the Smart Energy Systems conference (SESAAU2024).

District heating is recognised as a key technology for the efficient integration of renewable energy and waste heat sources into our energy systems. For district heating management, demand-side management is seen as a promising technical solution. Various research activities show that the application of this technical solution leads to significant cost and emission reductions, thus contributing to the decarbonisation of the heat supply in buildings.

To demonstrate novel concepts and technologies for demand side management in thermal networks, case studies are compiled and analysed. The cases reflect different levels of technology readiness for both new and existing buildings, as well as laboratory systems. For the evaluation, different key parameters are collected. These parameters include, for example, building characteristics, energy storage options, thermal network specification and type of demand side management approaches. Other detailed technical and non-technical information (e.g. energy supply scheme, business model) is also recorded. The publication presents the main findings of the evaluation of the different case studies, the lessons learnt and the recommendations for action.

The lessons learnt from the case studies on technologies, buildings or districts will help to facilitate and improve demand side management in district heating systems in the future. The resulting recommendations for action will support the implementation and transferability of the recommendations to research and industry stakeholders.

The work carried out presents the results of the collaborative research work within the IEA EBC Annex 84 on Demand Management of Buildings in Thermal Networks.

Contribution to the Smart Energy Systems conference (SESAAU2024).

The digital infrastructures of both buildings and the 4th Generation District Heating (4GDH) system are critical for enabling a variety of improved energy management and services across the network. Implementing a digitalization solution requires setting up a comprehensive infrastructure, which includes deploying a large number of sensors throughout the system and establishing their connections in a machine-readable format. This setup is crucial for facilitating automated data management, enabling advanced data analyses, and supporting the development of smart services. Semantic interoperability in buildings and 4GDH is a central theme of this critical review. Semantic Interoperability refers to the ability of different systems and organizations to communicate and operate seamlessly together, which is foundational for optimizing energy efficiency and advancing decarbonization efforts. In the context of digitalized energy systems, semantic interoperability works on the harmonization of digital infrastructures across buildings and 4GDH. This enables not only the real-time exchange of data but also the synchronized management of energy flows to meet dynamic demands efficiently. For instance, through interoperable systems, buildings can adjust their energy consumption based on real-time data from 4GDH, leading to significant enhancements in energy conservation and reductions in carbon emissions. This paper reviews the current state of semantic interoperability in buildings and 4GDH, focusing on how digitalization serves as the backbone for these interactions. It examines various methodologies and technologies that have been developed to enhance interoperability, assesses their effectiveness, and identifies gaps and challenges in current practices. Through this analysis, the review aims to highlight how improved interoperability can lead to better energy management solutions that are crucial for achieving greater energy efficiency and meeting global decarbonization targets.

Contribution to the Smart Energy Systems conference (SESAAU2024).

The decentralized energy techniques like heat pumps and storages are increasingly applied to ensure the balance between supply and demand. However, rather than barely meeting the demand, the need for zero energy buildings in the EU landscape aims to respond to the fluctuations and stabilize the grid by developing sector coupling between thermal and electricity systems. Accordingly, demand side thermal energy flexibility plays a key role in enhancing the stability of the power grid. Moreover, as the district heating transition towards fifth generation, the supply temperature can be reduced to 40 degC, which faces challenge when peak load occurs. Hence, the coupling also contributes to the peak shaving in district heating networks. Due to efficient coupling of the thermal and electricity sectors, power-to-heat (P2H) assets such as heat pumps as well as electric boilers play an increasingly important role in unlocking flexibility, both as boosters of the district heating network or stand-alone devices. However, there is a research gap in comprehensively analyzing the flexibility potential in such sector coupling networks. This study aims to develop a data-driven demand response strategy for such power-heat coupling systems, and the flexibility potential will be analyzed thoroughly through simulation from a district heating connected energy community in Großschönau, Austria. Furthermore, novel midterm storage solutions, such as phase change materials (PCM), will be considered to incorporate with district heating and P2H assets.

Contribution to the Smart Energy Systems conference (SESAAU2024).

This brochure aims to showcase a selection of case studies that illustrate various ways of implementing demand side management in buildings connected to thermal networks. It presents 15 detailed case studies, all integral parts of the comprehensive research project. Each case study is thoroughly examined, covering aspects such as research objectives, collaboration models, and demand response control mechanisms. Furthermore, it describes the results and conclusions of each study, highlighting valuable lessons learned and best practices observed throughout the project duration.