Water–Energy Co-Production by Coupling Photothermal Membrane Distillation with Thermal-Osmotic Energy Conversion

The shortage of freshwater resources and the depletion of fossil fuels have emerged as two pivotal challenges confronting global development. Photothermal membrane distillation (PMD) technology, a technique that harnesses solar energy for seawater desalination, not only produces freshwater but also mitigates the pressure of energy depletion. However, its sole focus on freshwater production no longer meets the demands of the energy market. Based on this, this study proposes a power–water cogeneration system based on PMD and thermal-osmotic energy conversion (TOEC) technology. The system achieves power–water cogeneration by changing the supply side heat source structure of TOEC technology and coupling it with traditional PMD technology. The experimental results showed that under the illumination condition of solar intensity of 4 kW·m−2 for 3.5 h, the fresh water production and water production rate of the system reached 2.23 g and 1.39 kg·m−2·h−1, respectively. Meanwhile, the fresh water output pressure reached 0.91 bar, and the output power density was 0.0456 W·m−2. This system is expected to provide a new solution to address the global shortage of freshwater resources and the depletion of fossil fuels.