Thermofluidynamics of colloidal energy system

The international energy agency (IEA) has stated that the global energy consumption by the industrial sector has grown by 61% compared to the levels recorded in the 60s. The increased energy consumption has implied a considerable increase in the levels of C0 2 present in the atmosphere, bringing to global attention the problem of global warming. In this world context, the industrial sector is called to improve the efficiency of its production cycles, in order to reduce emissions that are harmful to humans and the environment. One way is to exploit the energy that is dissipated in the environment, through waste heat recovery systems. Most of the heat produced around the world is at low temperature, ie under 200 C ◦ , and energy recovery from a source of this type is very difficult. The CERES system is an energy harvesting system pointing to recovery of heat in this range of temperatures: the idea was born to respond directly to the challenge of NASA ” Surviving extreme spatial environment and the first step was to create the prototype known as as DOUGHNUT, or rather aDatptive cOloalidal accUmulatinG / HarvestiNg UniT. This system uses an external thermal gradient (generated for example by exhaust gases), combined with a permanent magnetic field, to generate a motion of convection and translation of the ferrofluid inside. With an appropriate configuration of the collection coils, using Faraday’s law it is possible to recover and store energy from these flow motions. After having described the prototype in its basic components, and having provided an overview of the fluid used, we move on to the description of the mathematical model used to describe the motions inside, with a detailed overview of all the forces that play a fundamental role in this context. Then we move on to describe the numerical method used for the discretization of the mathematical model, thanks to which we obtain the fluid dynamic views of what happens in the area of interest. Future developments of this prototype will provide for the use of these results to find the configuration of the collection coils in order to maximize energy recovery.