STORM

District heating and cooling (DHC) networks play a crucial role in distributing energy to homes and buildings, yet there is scope for improvements in energy efficiency and market deployment. Johan Desmedt tells us about the H2020 STORM project’s work in developing, deploying and demonstrating a generic DHC network controller, which can be applied across both existing and new networks

A great deal of research attention has focused on district heating networks over recent years, aiming to improve energy efficiency and increase the use of renewable energy. While progress has been made, there is still scope for further improvement, an issue which researchers in the STORM project are addressing. “The project tackles energy efficiency at district level. We aim to develop, demonstrate and implement a smart district heating and cooling network controller, that can reduce the peak in a district heating network by 20 percent,” says Johan Desmedt, the project coordinator. The controller is designed to be applicable in both existing and new systems. “The idea of the STORM controller is that it will be applicable in both what we call third generation network systems and also fourth generation network systems,” explains Desmedt. “So fourth generation network systems are characterised by a lower supply temperature, and also by improved energy efficiency.”

The project is aiming to develop a generic controller, looking towards its wider deployment across Europe in different district heating and cooling networks. The network controller will be demonstrated at two pilot sites; the network of Mijnwater BV in the Dutch city of Heerlen, and Rottne in the Swedish city of Växjö. “In Rottne, we have a third generation district heating system. This type of system is quite common in Europe,” outlines Desmedt. This network makes up about 10,300 metres with a total volume of about 64 m³. The production is based on two wood chip boilers, complemented with a traditional oil boiler. The purpose of the STORM controller here is to minimize the oil usage. The system of Mijnwater BV by contrast is more advanced; the differences between the two sites will help demonstrate the wider applicability of the network controller in Europe. “The network of Mijnwater BV is a highly advanced, innovative fourth generation district heating and cooling network,” says Desmedt. “Flooded mine galleries act as renewable energy sources and provide a total of 500,000 m² floor area connected to a low temperature district heating and cooling network. The purpose of the STORM project is to develop a controller in order to go towards a selfsufficient district in terms of energy.”

A number of different sources are used to generate the energy distributed within these different networks, varying according to the local climate. The network in Rottne utilises a biomass boiler, combined with an additional fuel boiler; Desmedt says the latter is an expensive

form of energy, a prime motivation in the project’s work in developing three specific control strategies, the first of which involves controlling demand. “We want to exclude the fuel boiler by a technique called peak shaving, by reducing peaks in the network system, and controlling the distribution,” he explains. Researchers are also investigating market interaction. In the last control strategy the DHC network provides balancing services to the electrical grid, later called the ‘market interaction’ control strategy. As explained above the clue in smart electrical grids lies in the creation and application of flexibility. When both grids are coupled, for example by means of a heat pump and/ or a CHP, the intrinsic flexibility in the DHC network can be used to control these heat pumps or CHPs depending on prices on the day-ahead and intraday market, and therefore increase the production unit owner’s profit. Another advantage is that this control strategy supports a productionmix with a high share of renewable energy at system level in this way.

The third business feature is that researchers aim to balance the supply and demand of heat in a cluster of buildings. In this way, the use of excess heat or renewable heat in a cluster is maximized, making the cluster self-sufficient and minimizing the consumption of additional primary energy, which Desmedt says is one of the project’s major objectives. “We can do this by using the thermal inertia of the building’s mass, or by demand-side management measures,” he explains. A key element in this work is the use of self-learning algorithms to more closely match supply to demand. “The algorithms learn from data – so the controllers also record the data from the network. Based on that data, you can forecast energy demand,” continues Desmedt. “And there we reached an accuracy of around 7-8 percent, so we are able to predict the total demand on a district heating system with an accuracy of 7-8 percent.”

Researchers also aim to increase the use of waste heat and energy from renewable sources, which is of course a major priority given widespread concerns about energy sustainability. “One of the aims of the project is to increase the amount of energy from renewable sources that is supplied via district heating and cooling network systems. For example, we want to increase biomass use in Rottne,” says Desmedt. Europe is home to a wide variety of district heating and cooling networks, utilising different sources of energy and with different legal frameworks, yet Desmedt says the controller will be widely applicable. “We’re not targeting one specific type of

@Nathalie Belmans - EnergyVille.

energy supply or type of network. It can also be applicable in the geo-thermal area, or solar district heating network systems, or biomass, or many others,” he stresses.

A large amount of data has been gathered so far on not only energy consumption patterns, but also behaviour and network temperatures. This will provide solid foundations for evaluating the performance of the controller. “We measured a whole district heating system. So we looked at the temperature in the network, the flow in the networks, the energy consumption of the buildings, and more. So we measured all the data without the presence of the STORM controller,” explains Desmedt. Soon the smart controller will be implemented at the pilot sites, then its performance and impact on energy efficiency will be assessed. “It will be able to communicate with the district heating and cooling network systems. Then we will evaluate and compare it with measurements before the controller was implemented,” continues Desmedt.

From this, researchers can also look to add further elements to the controller, fully maximising the benefits of increasingly advanced self-learning algorithms. Desmedt and his STORM colleagues are also laying the foundations for further research in this area, with educational activities planned for PhD and Masters students and professionals. “We want to extend this work with additional features, for instance in sub-station control, where quite a lot of work is still needed ,” he says. The project is also working on replication activities, looking towards potentially implementing the controller more widely across Europe. “We are now discussing how we can do this in an easier way, maybe by developing a new concept,” says Desmedt. “With STORM, we want to contribute to the deployment of district heating and cooling networks across Europe, and the controller is one of the features which we can replicate.”

Self-organising Thermal Operational Resource Management (STORM)

The objective of this project is to develop and demonstrate a generic district heating and cooling network controller. Generic in this sense means that the controller will be applicable to all generations of networks, including widely spread 3rd generation networks, but also very innovative 4th generation networks.

1.97 million euros. The STORM project is funded by the European Union’s Horizon 2020 Programme under Grant Agreement no. 649743.

VITO, EnergyVille (EV) [a cooperation between VITO, the University of Leuven and R&D center Imec], Mijnwater, Euroheat & Power, NODA, VEAB, and Zuyd.

Johan Desmedt Unit Energy Technology VITO/EnergyVille Genk, Belgium T: + 32 14 335 841 E: Johan.Desmedt@vito.be W: http://storm-dhc.eu/

Johan Desmedt

Johan Desmedt received his degree in electrical engineering in 1993 from the BME, Belgium. He is currently with the Energy Technology department of the Flemish Institute for Technological Research (VITO) and EnergyVille, Belgium. After conducting research in the field of energy efficiency in buildings, building simulation and modelling, and underground thermal energy storage, he became project manager in 2009. He is currently project manager of national and international research activities in the district heating and cooling.