New solarclave uses nanoparticles to create steam

Jul 09, 2013 by Bob Yirka report
(A) Schematic and photograph of the closed-loop solar autoclave showing (I) the steam generation module, (II) the connection module, and (III) the sterilizationmodule. The components of the systemare (a) sterilization vessel, (b) pressure sensor, (c) thermocouple sensor, (d) relief valve, (e and f) control valves, (g) solar collector containing the nanoparticle-based heater solution, (h) check valve, and (k) solar concentrator (a plastic Fresnel lens of 0.67-m2 surface area). (B) Schematic and photograph of the open-loop solar autoclave: the components of the system are (i) solar concentrator (44-in dish mirror), (ii) heat collector containing metallic nanoparticles, and (iii) sterilization vessel that contains a pressure sensor, two thermocouple sensors, a steamrelief valve, and two hand pumps and valves that control the input and output of waste. The solar concentrator dish system has a dual tracking system powered by a small car battery recharged by a solar cell unit. Credit: (c) PNAS, doi: 10.1073/pnas.1310131110

( —A team of researchers at Rice University has developed a solar powered autoclave based on solar energy and metal and carbon nanoparticles. In their paper published in the journal Proceedings of the National Academy of Sciences, describing their device, the group explains how it was designed and ways it can be used in areas without electricity.

An autoclave is a device that uses steam to sterilize surgical tools—most models use electricity to generate the steam and as a result are heavy energy users. Such devices are not practical in remote areas with no electricity and because of that people all over the world in remote regions are at a high risk of developing infections from surgical procedures performed with unsterilized tools. To address this problem, the team at Rice has developed an autoclave based on solar power—a solarclave—with a major difference. Other autoclaves simply attempt to boil water using solar power, but there are limitations due to inefficient capture of radiated energy when using plain water. To get around this problem, the team added metal and carbon to the water.

The nanoparticles absorb solar radiation far more efficiently than water—that heat is then transferred directly to the water in which the nanoparticles reside. The result is a device that can make water hotter than can be done using traditional solar heaters and works faster as well. The steam that is created is routed to a pressure cooker where the tools are placed. After 30 minutes the tools are clean enough to pass U.S. FDA sterilization tests. Also, because the nanoparticles are too heavy to rise into the air with the steam that is created, they remain in the water, for use over and over again.

The team built two models of their device. One was a closed loop system where the water in the steam was recaptured and returned to the boiler after it cooled. Such a system they report would be ideal for tool sterilization. The second model was built to demonstrate the feasibility of using the same technique to treat water sewage waste. In such a system, waste water is heated and turned to to create sterile clean enough to drink.

Explore further: Solar Kettle allows for boiling water off the grid

More information: Compact solar autoclave based on steam generation using broadband light-harvesting nanoparticles, PNAS, Published online before print July 8, 2013, doi: 10.1073/pnas.1310131110

The lack of readily available sterilization processes for medicine and dentistry practices in the developing world is a major risk factor for the propagation of disease. Modern medical facilities in the developed world often use autoclave systems to sterilize medical instruments and equipment and process waste that could contain harmful contagions. Here, we show the use of broadband light-absorbing nanoparticles as solar photothermal heaters, which generate high-temperature steam for a standalone, efficient solar autoclave useful for sanitation of instruments or materials in resource-limited, remote locations. Sterilization was verified using a standard Geobacillus stearothermophilus-based biological indicator.

Related Stories

Solar Kettle allows for boiling water off the grid

May 23, 2013

( —A company called Contemporary Energy has unveiled a new device it calls the Solar Kettle. It looks very much like a normal coffee thermos, but has flaps on one side that open to allow for collecting ...

Recommended for you

US urged to drop India WTO case on solar

14 hours ago

Environmentalists Wednesday urged the United States to drop plans to haul India to the WTO to open its solar market, saying the action would hurt the fight against climate change.

Is nuclear power the only way to avoid geoengineering?

21 hours ago

"I think one can argue that if we were to follow a strong nuclear energy pathway—as well as doing everything else that we can—then we can solve the climate problem without doing geoengineering." So says Tom Wigley, one ...

Finalists named in Bloomberg European city contest

Apr 23, 2014

Amsterdam wants to create an online game to get unemployed young people engaged in finding jobs across Europe. Schaerbeek, Belgium, envisions using geothermal mapping to give households personalized rundowns of steps to save ...

Bloomberg invests $5M in solar-powered lamp

Apr 22, 2014

Former New York Mayor Michael Bloomberg's foundation has announced a $5 million investment in an artsy-looking solar-powered lamp designed for use in off-grid populations in Africa.

User comments : 0

More news stories

SK Hynix posts Q1 surge in net profit

South Korea's SK Hynix Inc said Thursday its first-quarter net profit surged nearly 350 percent from the previous year on a spike in sales of PC memory chips.

FCC to propose pay-for-priority Internet standards

The Federal Communications Commission is set to propose new open Internet rules that would allow content companies to pay for faster delivery over the so-called "last mile" connection to people's homes.

Brazil enacts Internet 'Bill of Rights'

Brazil's president signed into law on Wednesday a "Bill of Rights" for the digital age that aims to protect online privacy and promote the Internet as a public utility by barring telecommunications companies ...

Phase transiting to a new quantum universe

( —Recent insight and discovery of a new class of quantum transition opens the way for a whole new subfield of materials physics and quantum technologies.

Imaging turns a corner

( —Scientists have developed a new microscope which enables a dramatically improved view of biological cells.