Solar-powered sterilisation of medical equipment in developing nations

The device can be easily put together by users and can generate solar energy even in cloudy conditions

Spotted: A partnership between MIT and the India Institute of Technology has produced a new solar-powered autoclave for sterilising medical equipment in developing nations, where access to electricity is limited. 

Autoclaves use steam to kill bacteria. For this, water needs to be heated either electrically or by burning fuel, which may be scarce in impoverished regions. 

The new solar-powered autoclave incorporates a tank that releases water into a set of pipes. The pipes are attached to a copper plate with a heat-absorbing black coating on its upper surface. That surface is also layered with transparent silica-based aerogel, which allows sunlight to pass through. Polished aluminium mirrors on either side of the plate also help to concentrate the sunlight and when the plate gets hot, the liquid water in the pipes turns to steam and reaches the autoclave.

A small-scale version of the device was tested in Mumbai and performed adequately, even under cloudy skies. Based on this, it was determined that a solar collector measuring about 2 square metres would be enough to power an autoclave equivalent in size to those used in most doctors’ offices.

Whilst the aerogel is still rather expensive to manufacture, with further research the entire device is expected to cost around €132 to make. With the exception of the aerogel, most of the materials are available to users, so they can build the system themselves.

“If we can get the supply of aerogel, the whole thing can be built locally, with local suppliers,” says MIT graduate student Lin Zhao. 

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