Utilization of low-grade heat for desalination and electricity generation through thermal osmosis energy conversion process.

• The hybrid system of TOEC and electrokinetic module was designed to obtain co-generation of fresh water and electricity. • Improved water production and promising output power density were obtained by optimizing the parameters of the hybrid system. • Excellent desalination performance of the common salt ions was achieved. Harvesting low-grade heat energy for simultaneous desalination and power generation is a meaningful and valuable work to address the energy and fresh water crisis. Here we report a novel hybrid system for co-generation of fresh water and electricity by coupling thermal osmosis unit and an electrokinetic power generator. Pressured fresh water will be produced in the confined cold side by the temperature difference across the hydrophobic PTFE membrane, based on the principle of membrane distillation. Pressured driven fresh water flows into the electrokinetic module and through the microchannels from one reservoir to the other, electricity will then be generated based on the ion selection effect at the microchannel walls. Fresh water production rate of 18.46 kg m−2 h−1 and output power density of 1.12 W m−2 were simultaneously obtained by this device at a temperature difference of 50 °C. This study combined the recovery of latent heat energy and desalination, which may expand the application approaches of low-grade heat energy recovery. [ABSTRACT FROM AUTHOR]