Active Road Rumble Energy Harvesting Panels

Abstract

Vehicles traveling through busy roads and highways waste a huge portion of their kinetic energy. Up to five percent of the car’s energy is lost due to braking. In an effort to save energy it is possible to harvest some of this lost energy through a mechanical device built into the road. With over 1 billion cars, there is a huge potential for a man made untapped energy to be collected and harvested. This presentation focuses on designing a mechanical system that collects the energy of cars passing over a depressible flapping road rumble panel. As the car passes over the flap, the panel depresses and turns a directional shaft. The energy of many panels is collected and is summed up in a continuously turning flywheel. The collected mechanical energy can then be converted into electrical energy. The panels would be located where car drivers encounter deceleration ramps, when approaching a stop sign or entering a toll plaza. The analysis of this active road rumbles concept involved 1) designing a prototype using a computer drawing software such as SolidWorks, then 2) modeling the system mathematically to figure out all the important and intervening parameters factoring in the expression of the equation of motion of such systems, and then finally 3) building a physical prototype to analyzes the performances of such systems. The SolidWorks drawings for the model have been created. The dynamical model used free body diagrams and Newton’s second laws to determine the different loads and the equation of motion of the road rumble system. The mathematical model took into consideration the parameters of a shock absorber with a spring/mass/damper system. The kinematic equations of the shaft and flywheels were used to determine the speed and acceleration of the power train. A physical prototype was tested manually for time and frequency responses. It has been found that the energy collecting flywheel is lightly damped and loses a small part of its energy to friction. A feasibility study was conducted to evaluate the economic viability of such system. The harvested energy was estimated by measuring the RPM of the flywheel, and it was found that such system have an acceptable return on the investment. It is envisioned that such harvesting energy systems can be used in many ways one of them is to empty a huge offshore silo tank filled with sea water and producing peak electrical energy by allowing the sea water back into the silo through a hydraulic turbine.