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Subproject 8

Sorption heat storage system and thermochemical network integration

Novelty of the solution of the subproject 

WP1: The development of a liquid sorption heat storage system using sodium hydroxide for space heating and domestic hot water is being advanced from a lab demonstrator to a commercially viable product with an energy density of 350 kWh/m3 and a payback period of less than 15 years. This will be a game changer, being highly flexible, compact and affordable, and offering also industrial applications for waste heat recovery.

WP2: Thermochemical (storage) networks (TCN) represent a new topic in research, promising better  exploitation of various thermochemical processes in industry and other sectors. As the chemical potential is maintained, lossless distribution and long-term storage becomes possible.

Research is advanced by:

  • Simulation models for sorption storage, climatization and industrial drying

  • Experimental build of a network section to study sorbent transportation to recognize potential issues such as crystallization

Objectives of the subproject 


  • Accelerate water uptake into aqueous sodium hydroxide by buoyancy forces

  • Operate with source temperatures below 0°C

  • Enable vapour compression to increase temperature gain

  • Advance calibrated simulation models for accurate performance predictions

  • Advance TCN and its potential for renewable heating, cooling and air-conditioning

  • Understand unique selling proposition of TCN


  • Reach pay-off period below 15 years by storage system simplification

  • Determine the long-term and cost perspective for TCNs


  • Understand social and political acceptance/appreciation for sorption STES and TCN

  • Provide alternative STES technology


  • Leverage use of renewable energy, even at building scale through sorption STES


  • Advance sorption heat storage development towards a commercial product

  • Reach an energy density of 350 kWh/m3

  • Demonstration of advanced, low cost sorption heat storage system, ready for field testing

  • Further development of key components of TCN and build of a lab-scale test bench

Research partners

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