A self-cleaning device made of wood aims to make small-scale desalination more practical
About a billion people around the world lack access to safe drinking water. Desalinating salty water into drinkable water can help to fill this dangerous gap. But traditional desalination systems are far too expensive to install and operate in many locations, especially in low-income countries and remote areas.
Now researchers at the University of Maryland’s A. James Clark School of Engineering have demonstrated a successful prototype of one critical component for affordable small-scale desalination: an inexpensive solar evaporator, made of wood. The evaporator generates steam with high efficiency and minimal need for maintenance, says Liangbing Hu, associate professor of materials science and engineering and affiliate of the Maryland Energy Innovation Institute.
The design employs a technique known as interfacial evaporation, “which shows great potential in response to global water scarcity because of its high solar-to-vapor efficiency, low environmental impact, and portable device design with low cost,” Hu says. “These features make it suitable for off-grid water generation and purification, especially for low-income countries.”
Interfacial evaporators are made of thin materials that float on saline water. Absorbing solar heat on top, the evaporators continuously pull up the saline water from below and convert it to steam on their top surface, leaving behind the salt, explains Hu, who is senior author on a paper describing the work in Advanced Materials.
However, over time salt can build up on this evaporative surface, gradually degrading performance until it is removed, he says.
Hu and his colleagues minimized the need for this maintenance with a device made out of basswood that exploits the wood’s natural structure of the micron-wide channels that carry water and nutrients up the tree.
The researchers supplement these natural channels by drilling a second array of millimeter-wide channels through a thin cross-section of the wood, says Yudi Kuang, a visiting scholar and lead author on the paper. The investigators then briefly expose the top surface to high heat, which carbonizes the surface for greater solar absorption.
In operation, as the device absorbs solar energy, it draws up salty water through the wood’s natural micron-wide channels. Salt is spontaneously exchanged from these tiny channels through natural openings along their sides to the vastly wider drilled channels, and then easily dissolves back into the water below.
“In the lab, we have successfully demonstrated excellent anti-fouling in a wide range of salt concentrations, with stable steam generation with about 75% efficiency,” says Kuang.
“Using natural wood as the only starting material, the salt-rejecting solar evaporator is expected to be low-cost,” adds research associate Chaoji Chen. The evaporator approach also is effective in other types of wood with similar natural channels. The researchers now are optimizing their system for higher efficiency, lower capital cost, and integration with a steam condenser to complete the desalination cycle.
Hu’s lab also recently developed another solar-heated prototype device that takes advantage of carbonized wood’s ability to absorb and distribute solar energy–this one created to help clean up spills of hard-to-collect heavy oils. “Our carbonized wood material demonstrates rapid and efficient crude oil absorption, as well as low cost and scalable manufacturing potential,” says Kuang, lead author on a paper about the research in Advanced Functional Materials.
“Wood is an intriguing material scaffold, with its unique hierarchically porous structure, and it is a renewable, abundant and cost-effective resource,” Hu says. “In our lab, the fundamental understanding of biomaterials (especially wood) leads us to achieve extraordinary performance that is competitive with widely used but non-sustainable materials.”
Among other projects, his lab has created light and effective “nanowood” insulating materials. It also has engineered “super wood” that is 12 times stronger and 10 times tougher than natural wood, and potentially may replace steel, titanium or carbon fiber in certain applications, he says.
The Latest on: Solar evaporator
via Google News
The Latest on: Solar evaporator
- Bendigo gold miner plans 60MW solar farm on old evaporation ponds on May 21, 2019 at 6:38 pm
An Australian gold mining company has announced plans for a 60MW solar farm to be built on former evaporation ponds used for underground mining near the gold mining centre of Bendigo in central ... […]
- Woodvale evaporation pond solar power plant unveiled by GBM Gold on May 21, 2019 at 6:37 pm
A mining company's $100 million plans for a solar plant at the Woodvale ponds could go ahead regardless of whether its current bid to stay solvent is successful, its CEO says. GBM Gold needs to raise ... […]
- Hanergy changes ME solar landscape with thin film cells on May 12, 2019 at 10:14 pm
Hanergy currently has 5 futuristic thin-film solar power technologies. These are Solibro’s CIGS co-evaporation technology, Alta Device’s GaAs technology, GSE’s CIGS flexible co-evaporation technology, ... […]
- Maharashtra has no plans to prevent evaporation in dams on May 7, 2019 at 4:50 am
AURANGABAD: Even as over 800 irrigation projects from Marathwada lose water to evaporation in a time of drought, the state government has not earnestly attempted to explore using solar panels to ... […]
- Inorganic perovskite absorbers for use in thin-film solar cells on May 6, 2019 at 5:39 pm
Using co-evaporation of caesium-iodide and lead-iodide ... Steve Albrecht, these optimized CsPbI3 layers were used to demonstrate perovskite solar cells with an initial efficiency of more than 12 % ... […]
- New solar still claims near-perfect efficiency in purifying water on May 4, 2019 at 5:00 pm
In a solar still, seawater, dirty water, or even green leaves are set inside a transparent plastic container, which can be as simple as a polythene bag, and set out in the sun. The light heats the air ... […]
- How We Can Dim the Sun to Survive Climate Change on May 1, 2019 at 2:11 am
Solar radiation management, or SRM ... published in Nature Climate Change found that SRM could reduce precipitation in some places, since less evaporation would occur. Using SRM to reduce climate ... […]
- Solar evaporator to enable cheaper small-scale desalination technology on April 17, 2019 at 5:28 am
April 17 (UPI) --The development of a new type of solar evaporator promises to power a new generation of cheaper and more efficient small-scale desalination technology. Roughly a billion people are ... […]
- Wood based solar evaporator could provide safe water on April 16, 2019 at 11:59 pm
An inexpensive solar evaporator made of wood could provide safe drinking water to people in regions where desalination systems are too expensive to install and operate. A self-cleaning device made of ... […]
- Solar evaporator offers a fresh route to fresh water on April 16, 2019 at 6:11 am
Researchers have demonstrated a successful prototype of one critical component for affordable small-scale desalination: an inexpensive solar evaporator, made of wood. About a billion people around the ... […]
via Bing News