Although autocultics are considered to be basic equipment for disinfecting medical equipment in health-care facilities in developed countries, they are often not available in developing countries with limited electricity supply. A new solar autoculsion sterilizer may be the answer to this problem.
The autoculsion sterilizer works by placing the item in high-pressure steam for at least 30 minutes, killing bacteria in the process. This steam comes from water and is heated by electric heating or burning fuel… In poor areas, this fuel may also be scarce.
This is the role of solar autoculsion sterilizers. Designed by MIT in collaboration with the Indian Institute of Technology, it combines a water tank to release water (through gravity) into a set of pipes. The pipes are glued to the bottom of a copper plate with a black coating that absorbs heat. The surface is also covered with a transparent silicon-based aerogel that allows sunlight to pass through — heating the plate — while preventing heat from escaping from the plate. In addition, polished aluminum mirrors on both sides of the plate help to concentrate sunlight on the board.
As a result, the plate becomes very hot, causing liquid water in the pipe to turn into steam. The steam rises to the top of the device, where it is squeezed through another pipe into the actual autoclave itself.
A small version of the device was tested in Mumbai and worked well even under cloudy skies. Depending on its performance, a solar collector of approximately 2 square meters (21.5 square feet) is determined to be sufficient to power a small autoculsion sterilizer, such as one used in a doctor’s office.
The cost of manufacturing aerogels is currently quite high, but it is hoped that once a more economical production method is developed, the entire plant will not cost more than $160 to manufacture. In addition, with the exception of aerogels, most materials may already be user-usable, so they can build their own systems.
A paper on the study was recently published in the journal Joule.