Periodic Reporting for period 1 - CharCool (Rethinking the future of clean cooling through a revolutionary class of thermally-driven chiller based on a novel bio-based thermochemical material)
Reporting period: 2024-10-01 to 2025-09-30
Building cooling and industrial waste heat are responsible for >200 Mtons CO2eq annual emissions, and this is expected to grow continuously in the near future due to climate change. Therefore, a 5-10% overall increase in energy efficiency in these sectors would eliminate tens of millions of tons of GHG emissions per year, benefiting the mitigation of the carbon footprint of systems and processes. Increasing renewable energy penetration in the building sector, currently at a modest rate of 10%, is a goal that can be achieved with the contribution of CharCool. On a different note, the total industrial waste energy in the EU through streams flowing at temperatures between 100°C and 200°C reaches 183 TWh. CharCool targets both challenges by proposing a revolutionary technology to exploit the most from low-enthalpy industrial waste heat or renewable sources to provide a novel cooling solution. This initiative aims to revolutionize the cooling industry by offering a flexible, reliable, and environmentally friendly alternative to conventional methods. Hence, CharCool will play a crucial role in the energy transition. Moreover, CharCool will also contribute to achieving UN sustainable development goals: SDG7 (Affordable and Clean Energy), SDG11 (Sustainable Cities and Communities), SDG12 (Responsible Production and Consumption), and SDG13 (Climate Action), and the simultaneous reduction of the carbon footprint at both system and cooling sector levels.
CharCool aims to develop a novel heat-driven sorption cooling system that uses water as an environmentally friendly, abundant, and safe refrigerant. The heat-driven cooling system works with waste heat or renewable heat all year long thanks to a novel groundbreaking bio-based Thermochemical Material (TCM) which constitutes the thermopiles. CharCool targets ambitious objectives: volume reduction of 40% and cost reduction of 50% compared to state-of-the-art sorption chillers. The CharCool project aims to advance the different building blocks required to materialize this concept to TRL4 (Technology validated in the lab).
Four main objectives are defined:
• Materials: Novel bio-based TCMs
• Thermopiles: Modular and rechargeable TCM thermopiles
• Sorption chiller and system integration
• Life cycle and circular thinking
CharCool aims to develop a novel heat-driven sorption cooling system that uses water as an environmentally friendly, abundant, and safe refrigerant. The heat-driven cooling system works with waste heat or renewable heat all year long thanks to a novel groundbreaking bio-based Thermochemical Material (TCM) which constitutes the thermopiles. CharCool targets ambitious objectives: volume reduction of 40% and cost reduction of 50% compared to state-of-the-art sorption chillers. The CharCool project aims to advance the different building blocks required to materialize this concept to TRL4 (Technology validated in the lab).
Four main objectives are defined:
• Materials: Novel bio-based TCMs
• Thermopiles: Modular and rechargeable TCM thermopiles
• Sorption chiller and system integration
• Life cycle and circular thinking
During the first year, the Consortium has been working on the development of Life Cycle Assessment (LCA) and circular design frameworks to support the technology's development, indicating the path for sustainable choices. In fact, the criteria, both technical and environmental according to the KPIs, to select the proper sorption material candidates for the thermopile were identified. These allowed the identification of the most promising TCM candidates to be studied and developed.
Moreover, novel and original methods to study the sorption properties of the TCMs have been developed, allowing the collection of fundamental experimental data to validate the multi-scale numerical model of the sorption processes under development. In parallel, micro- and nano-computed tomography imaging has also been used to reconstruct the structure and surface of the bio-based TCM, providing invaluable information for the CFD simulation of the heat and mass transfer processes.
Finally, a multi-objective optimization framework, which is the first step toward the digital twin of the entire system, has been developed and used to evaluate the potential impacts on energy and GHG emissions savings of the novel sorption technology in two different scenarios: residential applications (multi-apartment buildings) and data center cooling and waste heat recovery.
Moreover, novel and original methods to study the sorption properties of the TCMs have been developed, allowing the collection of fundamental experimental data to validate the multi-scale numerical model of the sorption processes under development. In parallel, micro- and nano-computed tomography imaging has also been used to reconstruct the structure and surface of the bio-based TCM, providing invaluable information for the CFD simulation of the heat and mass transfer processes.
Finally, a multi-objective optimization framework, which is the first step toward the digital twin of the entire system, has been developed and used to evaluate the potential impacts on energy and GHG emissions savings of the novel sorption technology in two different scenarios: residential applications (multi-apartment buildings) and data center cooling and waste heat recovery.
During the first year, the Consortium has achieved remarkable results in the identification of the most promising bio-based TCMs to be used in the novel thermopile. The novel thermopile will be applicable both in cooling using the CharCool technology and in heating to offer a clean solution for space air-conditioning.
The potential impacts the CharCool technology are wide.
When considering the integration in industrial processes to recover waste heat, for example, if we target 20% of the total industrial waste energy in EU through streams flowing at temperatures between 100°C and 200°C. This is 183 TWh of energy wasted every year. If only the 30% of this massive waste heat is recovered, stored, and used to meet the building cooling demand through the sorption chiller, a cooling energy of 35.7 TWh can be produced (COP=0.65 for the sorption chiller from SORP estimations). If the same cooling demand were produced with traditional reverse vapour compression systems (COP=3, primary energy factor for electricity 2.42 and CO2 emissions factor for electricity 229 gCO2/kWh), an electricity use of 11.9 TWh would have been needed. Furthermore, the system proposed could be used in the same way in the heating season (considering another 30%), without the sorption chiller, by replacing natural gas boilers (currently done by fossil fuels, e.g. methane with CO2 emission factor 66.7 ton/TJ; conversion efficiency 90%; primary energy factor 1.05). The GHG emissions reduction in the two cases will be:
GHG emission reduction for building cooling: 2.7 Mton CO2/year
GHG emission reduction for building heating: 35.6 Mton CO2/year
Another example is the application in multi-apartment buildings. Considering a 13-apartment building in Milan (Italy) with the building specifications of a common Italian building (see Tabula project, multi-family houses built after 2006) and with an occupied area of 100 m2 of solar thermal panels (compatible with the building footprint), it can produce enough thermal energy to supply the CharCool sorption chiller (on a typical summer day in Italy, about 160 kWh produced vs. 105 kWh input energy needed with a COP=0.65). The sorption chiller can save about 170 kWh of electric energy for a traditional air conditioning system (COP=3) in such a building during the summer season. Furthermore, the CharCool system has the advantage that the sorption material can be charged with waste heat recovery (not locally), thereby leaving the roof available for other RES installations, such as PV panels. Moreover, CharCool can also be used for storing and providing heating in winter. Knowing that the heating and cooling demand for multi-apartment and commercial buildings in Europe is about 1300 TWh, and comparing the GHG emissions with traditional technologies, i.e. a reversible heat pump with a SCOP=3, the GHG emission reduction for building cooling and heating can be around 99 Mtons CO2/year.
The potential impacts the CharCool technology are wide.
When considering the integration in industrial processes to recover waste heat, for example, if we target 20% of the total industrial waste energy in EU through streams flowing at temperatures between 100°C and 200°C. This is 183 TWh of energy wasted every year. If only the 30% of this massive waste heat is recovered, stored, and used to meet the building cooling demand through the sorption chiller, a cooling energy of 35.7 TWh can be produced (COP=0.65 for the sorption chiller from SORP estimations). If the same cooling demand were produced with traditional reverse vapour compression systems (COP=3, primary energy factor for electricity 2.42 and CO2 emissions factor for electricity 229 gCO2/kWh), an electricity use of 11.9 TWh would have been needed. Furthermore, the system proposed could be used in the same way in the heating season (considering another 30%), without the sorption chiller, by replacing natural gas boilers (currently done by fossil fuels, e.g. methane with CO2 emission factor 66.7 ton/TJ; conversion efficiency 90%; primary energy factor 1.05). The GHG emissions reduction in the two cases will be:
GHG emission reduction for building cooling: 2.7 Mton CO2/year
GHG emission reduction for building heating: 35.6 Mton CO2/year
Another example is the application in multi-apartment buildings. Considering a 13-apartment building in Milan (Italy) with the building specifications of a common Italian building (see Tabula project, multi-family houses built after 2006) and with an occupied area of 100 m2 of solar thermal panels (compatible with the building footprint), it can produce enough thermal energy to supply the CharCool sorption chiller (on a typical summer day in Italy, about 160 kWh produced vs. 105 kWh input energy needed with a COP=0.65). The sorption chiller can save about 170 kWh of electric energy for a traditional air conditioning system (COP=3) in such a building during the summer season. Furthermore, the CharCool system has the advantage that the sorption material can be charged with waste heat recovery (not locally), thereby leaving the roof available for other RES installations, such as PV panels. Moreover, CharCool can also be used for storing and providing heating in winter. Knowing that the heating and cooling demand for multi-apartment and commercial buildings in Europe is about 1300 TWh, and comparing the GHG emissions with traditional technologies, i.e. a reversible heat pump with a SCOP=3, the GHG emission reduction for building cooling and heating can be around 99 Mtons CO2/year.