COMTES Project Description

The three heat storage technologies that are addressed in the COMTES project are ‘compact thermal storage technologies’, that need less volume and have much lower heat losses over the time (a season) than conventional water based storage systems. Moreover, the new systems demand less collector area compared to water-based seasonal storage systems.

This makes these technologies promising candidates for the next generation of seasonal solar heat storage technologies that will enable the step to nearly fully renewable heat supply of buildings in Europe.
The overall goal of the COMTES project is the technological development and demonstration of three compact thermal energy storage technologies, in three parallel development lines:

Line A
Solid sorption heat storage: Thermal energy storage by adsorption of water vapour in a solid sorption material. As solid sorption material zeolite is used.

Line B
Liquid sorption heat storage: heat storage by absorption of water vapour in a liquid. Sodium hydroxide (NaOH) is used as the liquid sorption material.

Line C
Supercooling PCM heat storage: Storage of heat in a supercooling phase change material. The material used with the required supercooling characteristic is sodium acetate trihydrate – NaCH3COO * 3H2O.