| Abstract |
This research entails an exploration of a special alloy (Ni45Co5Mn40Sn10) to convert waste heat from non- commercial geothermal wells to electricity. The alloy utilizes brine’s heat from non-commercial geothermal wells. In this design, waste heat is directly converted to electricity using Multiferroic Alloys, thereby increasing the power output and efficiency as well as eliminating the need for heat exchangers before recycling the steam. The multiferroic alloy (Ni45Co5Mn40Sn10) is made up of Nickel, Cobalt, Manganese, and Tin. The alloy undergoes a reversible phase transformation from a nonmagnetic martensitic phase to a strong ferromagnetic austenite phase upon heating. When biased by a permanent magnet such as rare earth magnet and then heated, the change in phase from martensite which is nonmagnetic to Austenite which is magnetic causes a sudden increase of the magnetic moment which drives a current in the surrounding circuit as a consequence of Faraday’s law. The alloy undergoes low hysteresis reversible phase transformation and can be used even at small changes in temperatures such as 10Kelvins. In my preliminary studies, I designed a multiferroic (Ni45Co5Mn40Sn10) alloy that utilizes waste heat from brine to generate additional power. The alloy was surrounded by suitably placed coils and then placed adjacent to a permanent magnet. In the design, the steam coming from the well is used to heat the multiferroic alloy. The alloy then undergoes a reversible first order martensitic phase transformation from martensite at low temperature to austenite at high temperature. The martensitic phase is non-ferromagnetic while the austenite phase is highly ferromagnetic. The magnetic field momentum of the alloy increases rapidly when heated. Extreme fluctuation in the magnetic field momentum that cuts through the coil as the alloy transforms from non-ferromagnetic to ferromagnetic phase induces electromotive force into the coil (Faraday's law). Cooling the alloy in the air through natural convection and conduction induces an electromotive force of opposite polarity in the coil. Heating and cooling of the alloy results in continuous power generation. The martensitic transformation is extremely fast due to low magnetic hysteresis, the absence of diffusion and the presence of low energy mode of transformation between the martensitic phase and austenite phase. The speed of interface transformation in the alloy tends to the speed of light in a material. The rapid martensitic phase transformation results in the production of electricity at high frequency. The frequency of power generation is further increased by having several turns of the coil around the magnet. The magnet is placed such that their fields produce multiple phases of current in the coils. The heating process is achieved through the transfer of heat by convection from the steam to the alloy. The cooling process is accomplished through heat transfer from the alloy to the atmosphere by natural convection and conduction. Periodic heating and cooling of the alloy induce an alternating current in the coil. The temperature of the alloy will vary between the upper critical and lower critical temperatures to achieve continuous power generation. An optimized model results in steady and continuous power production through controlled steam flow into the alloy. Simulation studies indicate that the project can generate 15MW of electricity from brine. This will broaden the economic drivers in both developing and industrialized countries through increased and steady power production from geothermal wells which are currently unproductive. |