Transportation vehicles traveling on busy roads and highways waste an appreciable amount of their kinetic energy. The lost energy dissipation is due to many factors such as: the friction due to braking, the friction of the tires on the road, the friction of the vehicle body against the surrounding air, and the friction due to the engine’s moving parts. In an effort to save some of this lost energy, it is possible to harvest it through pneumatic and mechanical devices built into the road, especially on highly traffic highways. With over 1 billion cars in the world, there is a huge potential for tapping into the lost energy, and harvesting it for another use. This technical paper focuses on designing a pneumatic and mechanical system that collects the lost kinetic energy of multiple passing cars. A new energy harvesting system utilizing pneumatic and mechanical components has been developed. In this system, a vehicle’s tires pass over a pneumatic manifold system equipped with exciter keys. These keys are depressed and activate a pneumatic system to compress air. Each exciter key is coupled to a connecting rod and piston assembly. The compressed air generated by many exciter keys is then collected in an air tank and channeled to a pneumatic motor. The pneumatic motor transmits then a rotational motion to an electricity generator that produces electric energy. The electric energy can be stored into a series of batteries. The modular pneumatic manifold systems would be located where car drivers encounter deceleration ramps, when approaching a stop sign, or entering a toll booth plaza, etc. The pneumatic system was designed using a computer drawing CAD software. The vehicle’s kinetic energy losses are thoroughly analyzed and their distribution is comprehensively determined using the first principle of thermodynamics, and the thermodynamics theory for compressed air. Energy losses to the system keys and springs, and different friction losses are also determined. A pneumatic model of the manifold, and piping connections to the air tank has been programmed using a pneumatic software for modeling and simulation. An economic viability study of such systems has also been performed. Parameters such as the number of passing cars and the number of strokes on the exciter keys necessary to fill an air tank are determined. A physical prototype of the modular manifold has been built, and experimental measurements are expected to be performed in an upcoming second phase of the project. It is envisioned that such harvesting energy systems can be used to produce energy locally in remote road areas to power stop lights, or street lights. This type of system can also be adapted to be used with other transportation systems such as trains and buses to produce electricity for their respective stations when traffic is heavy.
A Fundamental Study for Design of Electric Energy Harvesting Device using PZT on the Road