Electrically Driven Interfacial Evaporation for High-Efficiency Steam Generation and Sterilization

Abstract

Electrically driven steam generation is a critical process for many heating-related applications such as sterilization and food processing. Current systems, which rely on heating up the bulk water to generate steam, face the dilemma in achieving a large evaporation flux and fast thermal response. Herein, we report a self-floating electrically driven interfacial evaporator for fast high-efficiency steam generation independent of the amount of loaded bulk water in the system. Through localized heating of the wicked water at the air–water interface, the evaporator has achieved an electrical-to-steam energy conversion efficiency of ∼90% at a heating power density of 10 kW/m2 and a fast thermal response of 20 s. The interfacial evaporation design not only achieves a high evaporation efficiency within a broad range of heating power densities by using different wicking materials, but also enables attaining a high evaporation temperature under low heating power densities by tuning the ratio of the vapor outlet area and the evaporation surface area. By integrating an interfacial evaporator within a sanitizer, the resultant system has demonstrated a faster steam temperature rise and superior steam sterilization performance than the commercial bulk heating-based approach.

Effect of Laser Parameters on Laser-Induced Graphene Filter Fabrication and Its Performance for Desalination and Water Purification

“…The performance of IE devices can also be enhanced by using efficient, conductive porous surfaces and can be used in a resistor mode . In a resistor mode, these surfaces act as a Joule heater (JH), and the JH-based evaporators have been demonstrated to work efficiently without restriction due to weather conditions. , The JH-based devices initially needed an additional conductive layer on the polymer, but laser-induced graphene (LIG) fabrication has led to a new dimension of JH-based hybrid evaporators. LIG is a facile, scalable, in situ, and single-step method of graphene formation by laser irradiation on polymeric surfaces. − LIG is reported to have an electrical conductivity of ∼5–25 S cm –1 , a thermal stability of up to ∼900 °C, and a high surface area of around 340 m 2 g –1 .…”

“…13 In a resistor mode, these surfaces act as a Joule heater (JH), and the JH-based evaporators have been demonstrated to work efficiently without restriction due to weather conditions. 14,15 The JH-based devices initially needed an additional conductive layer on the polymer, but laser-induced graphene (LIG) fabrication has led to a new dimension of JH-based hybrid evaporators. LIG is a facile, scalable, in situ, and single-step method of graphene formation by laser irradiation on polymeric surfaces.…”

Boosting the Viable Water Harvesting in Solar Vapor Generation: From Interfacial Engineering to Devices Design

“…[109] SVG system has been exploited for water treatment involving bacteria in line with the main design principles of steam sterilization and disinfectants-assisted sterilization. [110][111][112][113] In terms of steam sterilization, superheated vapor (121 °C) is fundamentally necessary to kill the bacteria. [114] As such, SVG system takes advantage of interfacial-heating-based solar autoclave, enabling fast-response (as short as 8.4 min for a full sterilization cycle) and energy-efficiency (100 J mL −1 for steam reaching 121 °C) sterilization, superior to that of the conventional sterilization techniques relying on electricity.…”

Laser-Induced Graphene (LIG) as a Smart and Sustainable Material to Restrain Pandemics and Endemics: A Perspective

“…Joule heating is a conventional way to sterilize and pasteurize food products. Many different materials ranging from polymers, nanotubes, , minerals, metals, , etc., have been utilized to analyze heat transfer phenomena and sterilization. The sterilization principle lies behind converting an electric current into heat as it passes through a resistance, which leads to the thermal inactivation of microbes.…”