Membrane-based Moisture Desorption-Absorption with Carbon Quantum Dot-enhanced Ionic Liquid for High-flux Passive PV Cooling and Water Harvesting

Project: Research

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Carbon neutrality is an effective pathway to address global warming. Solar energy plays a leading role in low-carbon energy transition, and PV power will witness a rapid increase around the world. A high PV panel temperature decreases the electric efficiency and shortens the lifetime; thus, PV cooling is critical to improving PV performance. Although active cooling can effectively reduce the PV temperature, the mechanical driving components cause high energy consumption and system complexity. Therefore, passive cooling naturally driven by spontaneous thermal processes is promising due to no moving parts. Besides, passive cooling is especially attractive in remote areas with limited maintenance, energy, and water.There is a growing need to develop energy-free, high-flux, and high-reliability PV cooling technologies. The major problems of existing PV cooling can be addressed for wider promotion by: (1) eliminating the energy consumption via novel passive designs, (2) increasing the cooling power via high heat/mass fluxes, and (3) maintaining high reliability via novel working fluids. This proposal seeks to achieve these goals by developing a novel membrane-based moisture desorption-absorption process with carbon quantum dot-enhanced ionic liquid for passive cooling and water harvesting. The microporous polymeric membrane features high specific areas that contribute to high mass flux in a compact structure. The naturally-driven desorption absorption processes involving large vaporization enthalpy yield high heat flux without energy consumption. The H2O/ionic liquids eliminate crystallization risk exhibited by conventional H2O/salt (crystallization hard to dissolve in passive designs) and intensify the desorption rate due to higher vapor pressures (increasing cooling powers of passive designs). The dispersion of carbon quantum dots into H2O/ionic liquids strengthens heat/mass transfer whilst avoiding deposition risk (increasing reliability). In addition to passive cooling, this module offers the unique ability to harvest water during desorption. Finally, fluid screening and machine learning-based geometry optimization further maximize the comprehensive performance.Numerical and experimental methods will be employed to complete the following project objectives: (1) Model and prototype development of the membrane-based desorption absorption module for passive cooling and water harvesting; (2) Kinetics characterization of the membrane-based desorption-absorption with carbon quantum dot-enhanced ionic liquid under key influential factors; (3) Long-term dynamic performance investigation of cooling/electricity/water output under transient weather conditions; and (4) Fluid screening and geometry optimization of the membrane-based desorption-absorption module to maximize the comprehensive performance. The proposed research is significant for developing advanced passive PV cooling with water harvesting, facilitating efficient, economic, reliable, and versatile solar power technologies in Hong Kong and all over the world. 


Project number9043363
Grant typeGRF
StatusNot started
Effective start/end date1/01/23 → …