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• A hybrid system was designed to achieve simultaneous generation of fresh water and electricity. • A water yield of 1.55 kg m-2 h−1 and an 19.5 % improvement of output power were obtained under 3-sun irradiation. • Night working mode was achieved by recycling the latent heat of condensation. • An additional 6 W m−2 peak electricity output power were obtained at night. The photovoltaic (PV) cooling system based on solar-driven interfacial water evaporation (SIWE) system can effectively reduce the temperature of PV panels and obtain fresh water, but it cannot work at night during which there is no heat source input. In this work, we proposed a novel SIWE-based PV cooling systems with optimized performance that can achieve all-day working. In this hybrid system, the heat generated by the PV panel is extracted as the form of vaporization latent heat through membrane distillation (MD). Then it transferred along with the condensation of water vapor and stored in Phase Change Material (PCM), which is used to achieve electric power generation by thermoelectric effect at night. The hybrid system can achieve an 19.5 % improvement of output power compared with that without cooling method. Additionally, a 1.55 kg m-2 h−1 fresh water output with a salt rejection rate more than 99.9 % are realized under 3-sun irradiation. At the same time, it can also achieve a peak power output of 6 W m−2 at night by the release of latent heat stored in PCM. This hybrid system may provide a new idea to broaden application scenarios of traditional SIWE-based PV cooling systems. [ABSTRACT FROM AUTHOR]

Low-grade heat energy is enormous and widely distributed around the world, but it cannot be effectively converted to electricity owing to the small temperature difference and fluctuating heat source. As a promising technology that can convert low-grade heat energy into electricity while obtaining additional freshwater, thermo-osmotic energy conversion has attracted attentions of numerous researchers. However, traditional thermo-osmotic energy conversion technologies lack the utilization of the accompanying variation in salinity gradients throughout the process. In this study, a hybrid system was presented to achieve simultaneous freshwater production and electricity generation by combining thermo-osmosis system with a salinity gradient power recovery module. Continuous operation of the thermo-osmosis system will naturally produce a range of salinity differences, which will then be converted into electricity by the salinity gradient power recovery module. Our results show that this hybrid system can optimally increase the electricity output by ∼0.99 W m−2 over the conventional thermo-osmotic energy conversion system. Overall, our research demonstrates a promising device to harvest low-grade waste heat for co-generation of electricity and freshwater. This innovative approach has the potential to broaden the application possibilities of thermo-osmosis technology. • Salinity gradient recovery combined thermal-osmosis hybrid system was proposed. • A theoretical model was developed to predict electricity output of the system. • Comparing to traditional TOEC, increasing electricity output by ∼0.99 W m−2. • Co-generation of freshwater and electricity was achieved under real seawater. [ABSTRACT FROM AUTHOR]

• 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]