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Reporting period: 2019-10-01 to 2021-03-31

The HEAT-INSYDE project aims to establish an integrated thermal storage system, based on thermochemical storage, in real-scale pilot demonstrations in residential buildings. This will be achieve by gathering end-user feed-backs in three different climatic regions across the European Union. These large-scale pilots will include both rented and privately-owned configurations and these are the easiest use cases both in low temperature heat distribution networks and hybrid application in electricity networks. The pilot demonstrations target an energy reduction of 25% with a very compact system: i.e. with a size less than 1 m3.
The proposal is based on two recent technological breakthroughs accomplished with a large contribution of TNO and TU/e. The first innovation concerns a multicyclic stable thermochemical material with a high energy density that can be produced on (semi-)industrial scale at low costs (one of the results of the CREATE project). The second innovation is related to a patented reactor principle that uses the full potential of the first-generation thermochemical material (Patent no. PCT/EP2018/072574). The effective energy density on a system level surpasses the state-of-the art water storage solutions by a factor of at least 10.
The consortium assembled for the HEAT-INSYDE project is industry dominated and brings together all the relevant stakeholders in the value chain: ranging from basic material production, material manipulation, reactor design and manufacturing, energy system integration to municipalities and real end-users. The consortium also includes the City of Eindhoven, bringing a large-scale pilot opportunity and a national funding multiplier. The knowledge base of the consortium consists of TNO, CEA and Eindhoven Technology University (TU/e), all having an excellent track-record in thermal storage technologies, underlined with their wide participation in EU projects in this area.
In the first 18 months of the project, the consortium has focused on all the aspects of the development of the heat battery (reactor, components unit and thermochemical material) and it began the preparation of the some demo sites.

• In collaboration with an external party, a new design for the heat battery reactor was finalized. This resulted into the manufacturing of a mini-prototype, an optimization of the manufacturing process and in the final design for the reactor. Now the first full prototype is under construction.
• The optimum shape and dimension of the thermo-chemical-material (TCM) was selected and successfully tested. A patent to protect the IP developed during this research is on preparation.
• The component box (that contains heat exchanger, condensor and evaporator) design was finalized and several preliminary tests were carried on. It is now in the manufacturing process. A patent to protect the IP developed during this research on the evaporator is on preparation.
• The project’s website is operative ( and several dissemination material has been prepared.

Moreover, the representatives of the consortium (the project coordinator, the project manager, a presentative from TNO, CEA and TU/e) have met few times the external advisory board, to collect technical and market feedbacks from experts from the renewable energy and energy storage sectors.
HEAT-INSYDE targets four Key Performance Indicators that will be addressed by our multidisciplinary consortium:

• compactness with 0.3-1 m3 heat storage material and system energy density ≥ 10 times state-of-the-art water solutions;
• five times cost reduction of the system compared to storage systems developed in other EU projects;
• system performance fully meets key end-user requirements;
• identification of the winning use cases for first market application through full and user-centric (real-life) validation of technical and economic viability of the heat battery integrated in different architectures in renewable electricity and heat systems.

To achieve these ambitious goals, the consortium has defined the following specific objectives to overcome the main technical and non-technical barriers regarding demonstration of the envisioned integrated heat storage to:

• develop an industrial production technology for guaranteed material performance and quality for at least 25 years;
• advance a closed-loop system to a prototype for real-life demonstration;
• optimize flexibility in application;
• ease maintenance and reduced maintenance costs;
• ensure safe and reliable operation;
• validate the economic viability and user acceptance in real-life demonstration;
• organize and develop the supply and value chain for a heat battery.

HEAT-INSYDE will contribute to the expected impacts in the call “LC-EEB-05-2019-20 Integrated storage systems for residential buildings (IA)” as follows:

• HEAT-INSYDE starts from TRL5 with as input TCM materials developed in CREATE and a validated lab-scale prototype of the closed-loop system (patented by TNO and TU/e). HEAT-INSYDE ends with end-user validation of the heat battery in 3 climates in Europe at TRL 7.
• Besides the end-user demonstrations, the project performs accelerated multi-cyclic tests in an emulation environment at CEA/LAB to prove the system reliability and performance over a period of 25 years. The reactor design will be mostly based on optimizing off-the-shelf components, with durability of at least 25 years. HEAT-INSYDE optimizes the components combination, considering the reactor and humidifier to be the most challenging.
• The delivered system will have a storage compartment below 1 m3 and an expected maximum volume of 1.5 m3. This fits the available space in most single dwellings,
• The heat battery will be installed in a highly insulated row dwelling with an annual tap water usage of 7 GJ and a heating demand of 7 GJ on annual basis. The overall energy reduction will be about 43%. The heat battery and solar collector combination covers the tap water demand for >72%, charging the battery and creating hot tap water in parallel.

The fact that more than 60 % of the energy consumption of a typical European household is in the form of thermal energy (heat and/or cold, with some countries even >80%) underlines the potential of the HEAT-INSYDE heat battery.
The Infographic that collects the key aspects and innovations of the project.