A 3D‐Structured Sustainable Solar‐Driven Steam Generator Using Super‐Black Nylon Flocking Materials

Abstract

Solar‐driven evaporation is a promising way of using abundant solar energy for desalinating polluted water or seawater, which addresses the challenge of global fresh water scarcity. Cost‐effectiveness and durability are key factors for practical solar‐driven evaporation technology. The present cutting‐edge techniques mostly rely on costly and complex fabricated nanomaterials, such as metallic nanoparticles, nanotubes, nanoporous hydrogels, graphene, and graphene derivatives. Herein, a black nylon fiber (BNF) flocking board with a vertically aligned array prepared via a convenient electrostatic flocking technique is reported, presenting an extremely high solar absorbance (99.6%), a water self‐supply capability, and a unique salt self‐dissolution capability for seawater desalination. Through a carefully designed 3D structure, a plug‐in‐type BNF flocking board steam generator realizes a high evaporation rate of 2.09 kg m−2 h−1 under 1 kW m−2 solar illumination, well beyond its corresponding upper limit of 1.50 kg m−2 h−1 (assuming 100% solar energy is being used for evaporation latent heat). With the advantages of high‐efficiency fabrication, cost‐effectiveness, high evaporation rate, and high endurance in seawater desalination, this 3D design provides a new strategy to build up an economic, sustainable, and rapid solar‐driven steam generation system.

A Low‐Cost 3D Spherical Evaporator with Unique Surface Topology and Inner Structure for Solar Water Evaporation‐Assisted Dye Wastewater Treatment

“…[ 11 ] A 3D‐structured evaporator, which consisted of multi‐surface black nylon fiber flocking boards, broke the upper limit of energy efficiency because of reduction in heat loss and increment in receiving irradiation. [ 12 ] 3D U‐shaped evaporator was also architected by assembling dual‐phase Cu x S nanorods into Cu foam and bending to desirable geometry with nanoscale light trapping and negligible conduction loss, which achieved a 94.5% energy efficiency. [ 13 ] A high efficiency beyond the theoretical limit was achieved by a 3D photothermal reservoir that was made up of a cotton core wrapped by a reduced graphene oxide‐based aerogel sheet owing to minimized heat conduction loss and maximized energy gain from the surrounding.…”

Structure Architecting for Salt‐Rejecting Solar Interfacial Desalination to Achieve High‐Performance Evaporation With In Situ Energy Generation

“…In another design as shown in Figure 8b, a solar absorbing plate is located at bottom and extra evaporative boards are vertically inserted into it for environmental heat harvesting. [ 119 ] In both these designs, the wet components without light illumination are cooler than the environment due to the evaporative cooling effect, which allows for solar evaporation enhancement with the additional energy input from the warm air. Environmental heat can also be supplemented by solar absorbing surface through reverse convection and radiation.…”

“…Reproduced with permission. [ 119 ] Copyright 2018, Wiley‐VCH. c) Environmental heat harvesting by spatial water supply.…”

Energy Matching for Boosting Water Evaporation in Direct Solar Steam Generation

“…Different from water transport part of other evaporators, the evaporator added a water regulation link. [ 61–64 ] The water on the evaporative surface could be decreased by reducing water transport speed. The RE for evaporation would more closely match the IE.…”