In the transition towards a fully sustainable energy system, thermal systems are a key technology to significantly reduce CO2 emissions and local pollution, as well as to integrate residual energy sources and exploit flexibility. 

By 2050, regional, integrated and interconnected thermal networks will offer its users decarbonized, efficient, reliable and affordable energy solutions based on a high share of renewable energy sources, supported by digitalization. Digitalization allows district energy companies to offer diversified products and services that are highly automated, standardized, and personalized. EnergyVille performs top basic, applied and industry-driven research to make thermal networks more intelligent, digitalized, autonomous as well as energy efficient. This leads to generic technologies and methodologies resulting in novel products and services that facilitate optimal design, optimal control, and improved maintenance of thermal networks.

With thermal storage, surpluses of heat or cold are stored to be used when necessary. In other words, the supply of heat or cold is disconnected from the demand. This solves the daily imbalance between the heat demand at household level and the supply of heat from renewable sources (such as solar collectors or PV-coupled heat pumps). EnergyVille conducts research into the development, demonstration and implementation of intelligent control systems for energy storage systems. In addition, intelligent charge status determination of storage, integrated storage concepts and compact thermal energy storage can be counted among the research topics.

Within the conversion technology activity we develop technological solutions that enable an increased recuperation of residual and renewable thermal energy via efficient, flexible, and cost-effective conversion systems and ease the transfer of thermal energy within and between different energy networks carriers. The development of tools for automated component design contributes to the creation of innovative conversion systems by harvesting their full potential.
 

Erik De Schutter

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Erik De Schutter

Business Developer Thermal Energy Systems at EnergyVille/VITO
Johan Van Bael

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Johan Van Bael

Project Manager Energy Technology at EnergyVille/VITO
Thermal networks
Thermal storage
Thermal conversion

Smart District Heating and Cooling Control

thermische systemenEnergyVille works on technologies tackling the energy efficiency of district heating networks. We have developed a smart DHC controller based on self-learning algorithms that enables to maximize the use of waste heat and renewable energy sources in DHC networks. The controller optimises the consumption of the buildings and districts and the demand of the network and optimally uses the potential of activating the building thermal mass as thermal energy storage system. The technology also controls the supply and consumption side (demand side management) of district heating networks and the different components of the energy system (such as storage units, heat pumps, etc.).

Network design

netwerkontwerpThermal networks are an important means to reduce the primary energy use for heating and cooling. Given the many design variables involved, the optimal design of thermal networks is nontrivial. Because manual and intuitive designs will most often lead to sub-optimal solutions, the use of optimisation methods is advised. Within EnergyVille we work towards the next generation network topology optimisation based on geo-spatial information (e.g. energy sources, energy users, installed storage systems). Starting from this input, the optimal routing and temperature level for the thermal network piping and optimal location of storage and conversion units can be determined.

Analysis

Substations in thermal grids make the connection between the grid and the buildings or installations connected to it. Traditionally, they are built with one or more heat exchangers, some piping and valves to regulate the flow and pressures, and a control framework combined with (limited) sensor equipment. Any flaw or fault in these substations results in an increased return temperature of the grid, which is extremely detrimental for low temperature operation and energy efficiency. These flaws and faults occur more than often in practice; studies have shown that up to 75% of all installed substations exhibit some kind of faulty behaviour.

To rapidly identify these faults or flaws, EnergyVille is developing automated methods for fault detection, fault diagnosis and correction for poorly working substations and building installations based on the use of big data. Adding this intelligence to substation and/or network controllers allows an easy and remote detection of inefficiencies in the system, which on their turn reduces the costs for maintenance and operation costs for both service companies and network operators. In addition, EnergyVille works on methods to lower the return temperature of heating networks significantly in order to increase the efficiency of the energy systems.

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EnergyVille also focuses on thermal energy storage technologies. With thermal storage, surpluses of heat or cold are stored to be used when necessary. In other words, the supply of heat or cold is disconnected from the demand. This solves the daily imbalance between the heat demand at household level and the supply of heat from renewable sources (such as solar collectors or PV-coupled heat pumps). Various techniques can be used to store heat or cold, from water tanks to the more exotic sounding PCM (Phase Change Material) and thermochemical storage. The increasing use of renewable energy sources and residual heat from businesses and buildings are driving forces behind the use of energy storage. Furthermore, storage can also add operational flexibility and it contributes to increasing the efficiency of the energy system.

Thermal energy storage systems are mainly used in industrial processes and buildings. In these applications about half of the energy is used in the form of thermal energy. Thermal energy storage systems can help to keep the energy demand and supply in balance in different time frames. For example, a water buffer for domestic hot water stores heat for several hours or days, while underground borehole energy storage can store heat for an entire season.

Thermal storage can also play an important role in connecting thermal and electrical grids. To connect thermal energy storage to an electrical grid, conversion systems such as heat pumps or ORCs are required. With thermal grids, storage can play a balancing role between energy production, conversion systems and users, both on short (day-night) and long-term (winter-summer). EnergyVille conducts research into the development, demonstration and implementation of intelligent control systems for energy storage systems. In addition, intelligent charge status determination of storage, integrated storage concepts and compact thermal energy storage can be counted among the research topics.

Optimal heat recovery

For optimal heat recovery via heat exchanges a lot of parameters need to be optimized at the same time. It is important to have a heat exchanger with a high effectiveness and reduced pressure drop, but from the other side it is also important to minimize the usage of material and in some cases also the size/dimension needs to be minimized (or fit within certain boundary conditions).

Within EnergyVille we focus on the development of software packages for detailed simulation and optimisation of flow and heat transfer in (compact) heat transfer devices. The software is based on  new macro-scale modelling techniques for fast evaluation of ‘average’ flow and temperature in heat transfer devices with fin arrays.

In order to validate new designs of heat exchangers we are equipped with micro-scale testing infrastructure (measurements on arrays of fin structures including flow velocity measurement via Particle Image Velocimetry (PIV) and temperature measurement via Thermographic PIV).>

Low-temperature power generation

Within low-temperature power generation we focus on

  • Steady state modeling and optimization of ORC power systems including thermodynamic optimization, thermo-economic optimization, optimal fluid selection and hybrid cooling systems
  • Dynamic modeling and control of ORC power systems via Modelica (the ThermoCycle library) with focus on fast variations in boundary conditions and opimised start-up and shut-down
  • Evaluation of optimal working fluids for ORCs using the open-source Coolprop library
  • Design of small-scale prototypes of ORCs

Flexible heat pumps

Within flexible heat pumps we focus on

  • Steady state modeling and optimization of ORC power systems including thermodynamic optimization, thermo-economic optimization, optimal fluid selection and hybrid cooling systems
  • Dynamic modeling and control of ORC power systems via Modelica (the ThermoCycle library) with focus on fast variations in boundary conditions and opimised start-up and shut-down
  • Evaluation of optimal working fluids for ORCs using the open-source Coolprop library
  • Design of small-scale prototypes of ORCs

Flexible heat pumps

Within flexible heat pumps we focus on

  • Assessment of control strategy influence on heat pump installations to exploit their energy flexibility including the impact on the heat pump performance, the mutual influence of control strategy and design specifications and the interaction of different energy systems in heat pump installations
  • Design optimisation and compact heat exchangers for charge reduction of heat pumps with environmentally friendly refrigerants
  • Assessment of innovative heat pump technologies (eg high temperature heat pumps for waste heat recovery, absorption cooling with solar energy)
  • Testing of energy flexible heat pumps with heat pump hardware-in-the-loop configuration (testing of different control strategies and system configurations)