Engineering students at Rice University have devised a method of using solar power to sterilize medical instruments. Their device, an autoclave version of a solar cooker called the ‘Capteur Soleil’ (invented three decades ago by Jean Boubour), successfully killed biological specimens left on tools.
Many medical tools are steam-sterilized in autoclaves (essentially metal boxes built to withstand high pressure steam). Medical waste can also be sterilized in autoclaves prior to disposal. Industry standard requires an autoclave to be held at 121 degrees Celsius for at least 30 minutes to achieve sterilization.
The Capteur Soleil consists of a series of curved mirrors that focus the sun’s energy to turn water into steam. The Rice students’ innovation was to force that steam through a modified hot plate, which in turn heats up the instrument-containing autoclave. Once the mirrors are aligned properly, it takes about an hour for the hot plate to reach sterilizing temperature, and another half hour to kill spores.
For their senior capstone design project, the members of Team Sterilize refitted the Capteur Soleil at Rice's Oshman Engineering Design Kitchen to sterilize medical instruments and supplies with the power of the sun. From left, David Luker, William Dunk, professor and team adviser Doug Schuler, Daniel Rist and Sam Major.
Credit: Jeff Fitlow/Rice University.
This device would obviously be a boon to communities without the fuel resources required to sterilize medical equipment. According to the students, any type of autclave can be placed in the system, and of course, everything is reusable.
You can see an explanation by the students below.