The Wax Actuator is a paraffin filled cylinder that extends a piston when the paraffin melts. A paraffin actuator can be made to operate a sun tracker. We have mounted an actuator on a sun shade (see below) and tested in our yard for over 3 months with no problems. Before this we cycled an actuator in a test bed with a 70 lbs load over 35,000 times with any performance degradation.
Wax Actuator with a Sun Shade