Ferrofluid-Based Generator Harvesting Waste Heat and Ambient Vibration

Ferrifluid is a stable colloidal suspension of permanently magnetized nanoparticles, in which Brownian motion keeps the nanoparticles from settling under gravity, and a surfactant is placed around each particle to provide short range steric repulsion between particles to prevent agglomeration. Since magnetic field device has no limitations analogous to electrical breakdown in its electric field counterpart, ferrofluids have become an excellent choice for micro-/nanoelectromechanical systems technology. On the other hand, ferrofluids have applications in the cooling of electronic devices, which has led to several designs of power generators using waste heat. In this work, we study a new version of ferrofluid generator harvesting both heat and vibration energy. A theoretical model based on fundamental physics principles is developed to evaluate the system's energy conversion efficiency (the ratio of generated power and the heat input). Further, we discuss the dependence of the output power on various design parameters (including the scale of the system) and methods to enhance the performance of the ferrofluid generator or potential aerospace applications.