Columbia University Scientists have developed a method of controlling the power of evaporating water to produce electricity.
2 novel devices have been developed that take power from evaporating water. One of them being a floating, piston-driven engine that creates just enough electricity to cause a light to flash and the other a rotary engine that drives a miniature car.
Research conducted by Ozgur Sahin, an associate professor of biological sciences and physics at Columbia University, showed when bacteria spores shrink with changing humidity they push and pull other objects forcefully.
A newer study to build a floating, piston driven engine, the researchers glued bacterial spores to the sides of a thin double sided tape creating a dashed line of spores. They did the same on the opposite sides of the tape but offset the line so that the dashes overlapped with gaps.
As the dry air shrinks the spores, the dashes curve, causing the tape to become wavy and shortening its length so if one or both end of the tape are anchored, the tap will tug whatever it’s attached too. On the other hand when the tape is exposed to moist air the tape extends and releases the force. The result of this is a new type of artificial muscle that is controlled with changing humidity.
In an experiment a dozen such tapes were placed side by side in a floating plastic case topped with shutters. The evaporating water made the air humid inside the case causing the muscle to elongate, opening the shutters and allowing the air to dry out. When the humidity was released from the case, the spores shrunk back and the tapes contracted, pulling the shutters closed and allowing humidity to rebuild thus a self sustaining cycle of motion was created.
The artificial muscles covered with spores function as an evaporation driven piston, joined with a generator, it produced enough electricity to cause a small light to flash.
A small toy car was also successfully powered by The Columbia Team’s other new evaporation-driven system- The Moisture Mill.