Periodic Reporting for period 2 - BEST-Storage (BUILDING ENERGY EFFICIENT SYSTEM THROUGH SHORT AND LONG SPECTRUM THERMAL ENERGY STORAGE)
Período documentado: 2024-05-01 hasta 2025-08-31
The BEST Storage project focuses on tackling and providing solutions towards the numerous challenges that lay ahead of the European heating and cooling market. By 2030, considering energy efficiency and environmental targets set out by numerous countries and regions throughout the world, the thermal energy storage market could experience threefold growth, reaching over 800 GWh of installed capacity globally. As the EU looks to fulfill its climate neutrality objectives for 2050, one of the key parts of the energy equation that must be solved is that of the heating and cooling markets in the EU-27 which accounts for 50% of annual energy consumption. For these reasons, energy scenarios often suppose a very substantial contribution of renewable energy penetration in the heating and cooling sector supported by the multiplying effects of cross cutting technologies such as thermal energy storage solutions.
The BEST-Storage project tackles these challenges and aims to use the best possible storage technologies for each specific energy demand.
Three storage concepts will be developed:
• a thermo-chemical loss-free energy storage for long-term applications.
• phase change material (PCM) slurry concepts for cold storage applications to provide load shifting and peak shaving.
• a vacuum insulated (VI) water storage vessel for heating applications such as domestic hot water (DHW) and space heating (SH) allowing also to provide load shifting.
These storage approaches will be integrated into complete heating and cooling building energy management systems and short-term storages (PCM-slurry and VI water storage) will be equipped with model predictive controls (MPC) that will benefit from variable electricity prices to reduce operational costs while helping the electricity grid to be more stable, secure and resilient. The storage solutions are inherently modular providing cost savings, flexibility in design, size and operation.
In total, four storage solutions will be developed and tested at different TRL levels:
• one thermo-chemical material (TCM) storage,
• two PCM slurry solutions (PCM emulsion slurry and PCM slurry with supercooling-crystalilization)
• one sensible water storage with vacuum insolation (VI).
Moreover, the storage concepts will be developed and tested in real conditions in three real demo sites.
• Demo-case in Estonia (Single family home): The TCM as well as the VI-water storages integrated into the building energy management system will be demonstrated for heating and DHW applications bringing the systems to TRL 7.
• Demo-case in Greece (Lab-house): The TCM as well as the VI-water storages integrated into the building energy management system will be demonstrated for heating and cooling applications bringing the systems to TRL 7.
• Demo-case in Spain (office building): A PCM slurry storage of 9 kWh including the Model predictive control (MPC) will be used for cooling shifting in a research center building to bring it to TRL 7.
Additionally, an emulated demo-case in Switzerland (single family house) is also included whereby a system for heating and cooling will be demonstrated in the laboratory using a PCM slurry storage of 9 kWh and a VI-water storage bringing the TRL to 6.
The BEST-Storage project tackles these challenges and aims to use the best possible storage technologies for each specific energy demand.
Three storage concepts will be developed:
• a thermo-chemical loss-free energy storage for long-term applications.
• phase change material (PCM) slurry concepts for cold storage applications to provide load shifting and peak shaving.
• a vacuum insulated (VI) water storage vessel for heating applications such as domestic hot water (DHW) and space heating (SH) allowing also to provide load shifting.
These storage approaches will be integrated into complete heating and cooling building energy management systems and short-term storages (PCM-slurry and VI water storage) will be equipped with model predictive controls (MPC) that will benefit from variable electricity prices to reduce operational costs while helping the electricity grid to be more stable, secure and resilient. The storage solutions are inherently modular providing cost savings, flexibility in design, size and operation.
In total, four storage solutions will be developed and tested at different TRL levels:
• one thermo-chemical material (TCM) storage,
• two PCM slurry solutions (PCM emulsion slurry and PCM slurry with supercooling-crystalilization)
• one sensible water storage with vacuum insolation (VI).
Moreover, the storage concepts will be developed and tested in real conditions in three real demo sites.
• Demo-case in Estonia (Single family home): The TCM as well as the VI-water storages integrated into the building energy management system will be demonstrated for heating and DHW applications bringing the systems to TRL 7.
• Demo-case in Greece (Lab-house): The TCM as well as the VI-water storages integrated into the building energy management system will be demonstrated for heating and cooling applications bringing the systems to TRL 7.
• Demo-case in Spain (office building): A PCM slurry storage of 9 kWh including the Model predictive control (MPC) will be used for cooling shifting in a research center building to bring it to TRL 7.
Additionally, an emulated demo-case in Switzerland (single family house) is also included whereby a system for heating and cooling will be demonstrated in the laboratory using a PCM slurry storage of 9 kWh and a VI-water storage bringing the TRL to 6.
The second reporting period of the BEST-Storage project has focused on developing and scaling the solutions for lab testing before moving on to their implementation in the demonstrators.
During this second reporting period, significant advancement has been reached while also experiencing some delays or deviations in results.
Looking at our main storage approaches and demonstrators, the following main achievements and technical progress has been reached:
i) Thermo-chemical (TCM) Storage (WP3)
Design challenges arose following performance shortcomings identified in the 1 kW A/D unit using ceramic architectures. Updates and subsequent design decisions have been assessed and implemented; the alternative consists in fluid recirculation on smooth tubes. This approach should increase the efficiency of the heat and mass exchanger while being more cost-effective alternative to the use of ceramic coating.
The lab scale combined tank for diluted and concentrated sorbent was successfully tested and will be implemented on the scaled prototype. Compared to an optimized state-of-the-art three-tank storage unit, a storage density improvement of 35% was achieved.
Design of the upscaled TCM Storage unit is finalized and manufacturing is underway.
ii) PCM and VI Water Storage (WP4)
The cost effective vacuum insulation sensible water storage has been tested at laboratory scale and achieved an energy density on the buffer vessel level is around 60 kWh/m3.
For the PCM storages, development of materials for both slurries has been finalized. Sodium formate-water (NaCHO2-water liquid solution forming solid of NaCHO2•3H2O) was selected for the PCM-Crys (supercooling crystallization) and Paraffin RT11/water mixture for PCM-Emulsion. Proposed raw materials (PCM and salts) fit defined specifications in terms of cost, energy density storage capability and stability. The formulation of the slurries (the two concepts) considering the criteria of stability under operation and storage conditions and larger scale are under development.
As elaborated in the Technical Progress, challenges have been encountered in the stability of both the scaled systems. Issues have been identified and are being addressed in order to minimize deviations.
iii) Demonstration (WP5)
Achievements so far are focused on effectively preparing the demonstration sites for the implementation of the project solutions.
Moreover, virtual demonstration cases have been characterized in order to assess the replication potential towards the end of the project.
During this second reporting period, significant advancement has been reached while also experiencing some delays or deviations in results.
Looking at our main storage approaches and demonstrators, the following main achievements and technical progress has been reached:
i) Thermo-chemical (TCM) Storage (WP3)
Design challenges arose following performance shortcomings identified in the 1 kW A/D unit using ceramic architectures. Updates and subsequent design decisions have been assessed and implemented; the alternative consists in fluid recirculation on smooth tubes. This approach should increase the efficiency of the heat and mass exchanger while being more cost-effective alternative to the use of ceramic coating.
The lab scale combined tank for diluted and concentrated sorbent was successfully tested and will be implemented on the scaled prototype. Compared to an optimized state-of-the-art three-tank storage unit, a storage density improvement of 35% was achieved.
Design of the upscaled TCM Storage unit is finalized and manufacturing is underway.
ii) PCM and VI Water Storage (WP4)
The cost effective vacuum insulation sensible water storage has been tested at laboratory scale and achieved an energy density on the buffer vessel level is around 60 kWh/m3.
For the PCM storages, development of materials for both slurries has been finalized. Sodium formate-water (NaCHO2-water liquid solution forming solid of NaCHO2•3H2O) was selected for the PCM-Crys (supercooling crystallization) and Paraffin RT11/water mixture for PCM-Emulsion. Proposed raw materials (PCM and salts) fit defined specifications in terms of cost, energy density storage capability and stability. The formulation of the slurries (the two concepts) considering the criteria of stability under operation and storage conditions and larger scale are under development.
As elaborated in the Technical Progress, challenges have been encountered in the stability of both the scaled systems. Issues have been identified and are being addressed in order to minimize deviations.
iii) Demonstration (WP5)
Achievements so far are focused on effectively preparing the demonstration sites for the implementation of the project solutions.
Moreover, virtual demonstration cases have been characterized in order to assess the replication potential towards the end of the project.
Results are under development, and therefore finalized results with their respective impacts are not reached yet.
Most developments are now in lab scaling and/or testing phases before being implemented in demonstrators.
Some sub-elements of the Thermo-chemical Storage unit have been successfully demonstrated at lab scale and are being scaled. This namely refers to the combined tank for diluted/concentraded sorbent.
The lab tests for the VI water storage with possibility to integrate with a heat pump or solar thermal have been finalized.
Most developments are now in lab scaling and/or testing phases before being implemented in demonstrators.
Some sub-elements of the Thermo-chemical Storage unit have been successfully demonstrated at lab scale and are being scaled. This namely refers to the combined tank for diluted/concentraded sorbent.
The lab tests for the VI water storage with possibility to integrate with a heat pump or solar thermal have been finalized.