Sept. 1, 2011
ANN ARBOR, Mich. – While methods of turning salt water into fresh water are tried and true, two University of Michigan researchers believe the sun offers a better way to power these processes.
U-M Mechanical Engineering Professor Kazuhiro Saitou and Post Doctoral Research Fellow Karim Hamza hope to covert sunlight into sustainable sources of energy to drive the low-temperature distillation and reverse osmosis methods of desalination. Their success could help provide a more efficient model for improving the supply of fresh water for human and agricultural consumption.
“Both processes are pretty energy intensive and costly, ” Hamza said. “The idea here is to bring the costs down. Solar power is abundant, particularly in the area of our studies around the Sinai Peninsula and the Red Sea. We want to explore how we can put it to use in ways that are functional, durable and cost-effective.”
Low-temperature distillation converts a portion of a salty water stream into vapor by heating the water to a sub-boiling temperature and exposing it to a dry air stream. The vapor is then condensed into fresh water by cooling the air stream. Reverse osmosis relies on high-pressure pumps to drive a salty water stream through a membrane. As the stream passes through, modules in the membrane capture the salt ions and fresh water emerges. The investigators will explore how solar thermal and photovoltaic technologies can be used to generate electricity to power pump motors in the reverse osmosis process or to heat water for the distillation method.
With .03 percent of the earth’s water consisting of easily accessible fresh water from rivers and lakes, affordable and efficient desalination processes are critical to leveraging this supply. In Egypt access to fresh water is a very real issue and accounts for the fact that an estimated 95 percent of the nation’s population lives on approximately 6 percent of its land – land that is in close proximately to the freshwater.
Prof. Saitou said he hopes his team’s work can provide the technological basis for a more sustainable, cost-effective means of supplying fresh water and food to a growing population in a changing global climate.
“Proactively working on the solutions to these inter-wound challenges is the urgent responsibility of the engineering discipline,” he said. “Our research on this technology may also help provide U.S. industry with an competitive edge in responding to the demands of regions in need within and outside of the U.S.”
The U-M investigators are working with researchers in Egypt on the project as part of the U.S. – Egypt Joint Science and Technology Fund. The U.S. Department of Agriculture will provide just over one half of the $250,000 grant to the U.S. team members. The Egyptian government will fund the balance for the Egyptian scientists participating in the study.
Contact: Paul Gargaro, Michigan Memorial Phoenix Energy Institute, 734-615-5678, firstname.lastname@example.org.