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
STORM Generic controller spans the generations 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.”
Generic controller 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
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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
The idea of the STORM controller is that it will be applicable in both what we call third generation network systems and also the fourth generation network systems. So fourth generation network systems are characterised by a lower supply temperature, and also by improved energy
efficiency
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.”
Renewable energy 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
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