Low-cost, high temperature and pressure sterilization at one-sun


  1. Developing an efficient, low-cost autoclave powered by natural sunlight and operate completely passively
  2. Reducing the risks of nosocomial infections in rural clinics

Lack of sanitation in human waste disposal, water purification, and medical facilities lead to infections in millions of Indians each year. Almost all of these infections can be prevented by sterilization using steam at high temperature and pressure. However, producing steam from water is an energy-intensive process due to the high latent heat of water. Conventional sterilization equipment such as electrical autoclaves and concentrating solar-powered autoclaves are complex and expensive, which have prevented their adoption in rural communities.

The aim of this research is to develop a low-costcompletely passive solar autoclave capable of reaching high temperatures and pressures (up to 200 °C, 15 bar) using natural sunlight. The core technology is based on the novel optically transparent, thermally insulating monolithic silica aerogel developed in our lab. The inherent spectrally selective nature of silica aerogels obviates the need for commonly used expensive vacuum tubes or concentrating optics to reach temperatures >200 °C. A 0.5 m2 module can provide 300 W capacity that can meet the needs of a typical household. Individual modules can be connected easily to scale up for different community needs such as in hospitals, public sanitation facilities, and food and water sterilization facilities.

The proposed aerogel solar autoclave have significantly lower cost compared to existing solutions by replacing the expensive components with the low-cost aerogel. The complete passive nature of the device also requires a lower operational cost. The technology is scalable to suit the needs of a variety of end users across India. In addition to sterilization, the same technology can be used to supply steam for industrial processes to reduce their carbon footprint. We are collaborating with researchers at IIT Bombay to explore the process steam applications in India.