SOLAR DESALINATION UNIT

Conversion of Low Grade Heat to Power through closed loop Reverse Electro-Dialysis, RED-Heat-to-Power

Participants: WIP (D) (coordinator), UNIVERSITY OF PALERMO (IT), FUJIFILM (NL), REDSTACK (NL), CIEMAT-PSA (ES), UNIVERSITY OF EDINBURGH (UK), UNIVERSITAT POLITECNICA DE CATALUNYA (ES)

Contact:  Guillermo Zaragoza, guillermo.zaragoza@psa.es

Funding agency: European Commission, Horizon 2020 programme

Background: The concept is based on the generation of electricity from salinity gradient using Reverse Electrodialysis with artificial saline solutions operating in a closed-loop. The original salinity gradient is regenerated by a separation step that uses heat at 40 – 100°C.

Objectives: The overall objective is to prove this revolutionary concept, develop the necessary materials, components and know-how for bringing it to the level of a lab prototype generating electricity from low-grade heat at higher efficiencies and lower costs than ever achieved to date. The specific objective of CIEMAT-PSA is to select the most suitable technologies for the regeneration process and the combinations of salts and solvents that can maximise the system performance.

Achievements in 2018: During this year, a test site was built at PSA to evaluate the combination of a reverse electrodialysis stack with an advanced membrane distillation technology to regenerate the salinity gradient. The results reached a record heat efficiency in the MD process (less than 50 kWh thermal energy consumed per m3 of distillate produced) by using a vacuum-enhanced air-gap configuration with multi-envelopes spiral-wound modules. This design was subsequently used in the pilot plant that was built in the facilities of Fujifilm in Tilburg (The Netherlands) and is currently under demonstration

Pilot-plant for assessment of combined reverse electrodialysis and membrane distillation