• Micro-grid conception for cold and electricity cogeneration

  • Electrical storage within hydrogen.

  • Low-grade wasted heat is used to drive the thermochemical système to produce and store cold.

General presentation of the project


     The core of the project is the integration and the coupling of these two storage technologies in a solar-powered, smart micro-grid for the building and industrial sectors. The approach aims at optimizing the performance of the micro-grid in terms of autonomy, efficiency, energy supply and consumption and solar forecasting. The innovative aspect concerns the development and the optimal integration of a system of storage/production of electricity/cold, by using hydrogen-energy vector and a thermochemical process, and by implementing a smart strategy and managing of this micro-grid facing intermittent resources and a variable load profile.

     The goal is to provide a proof of the technological concept through both a numerical and an experimental approach. Based on a complete dynamic system modeling, a representative small-scale pilot demonstrator will be implemented in Tahiti, which will permit to evaluate the feasibility and performance of the system.

Thermochemical processes are based on reversible chemical reactions between a solid and a gas. They allow the storage of energy in the form of chemical potential for a delayed cold production. They are particularly relevant for cold storage/production, due to their operational flexibility and their high energy density. The chemical reaction can be controlled mechanically by a compressor and/or thermally through heat input.

The electricity storage in the form of hydrogen is competitive with conventional electrochemical technologies, such as lead-acid and lithium-ion batteries (its energy density is 150 times higher). It is even more interesting if the energy used for the electrolysis of water and therefore the production of hydrogen, is of renewable origin. The electricity is then produced through a fuel cell system whose electrical efficiency is generally much higher than that of thermal machines. However, an important part of energy is dissipated in the form of heat during this energy storage and retrieval processes.