Thermal energy harvesting system based on magnetocaloric materials^★

Abstract

We numerically study the design of a thermomagnetic generator aimed to convert a heat flow into electrical energy. The device uses the variation of magnetization of a magnetocaloric material (MCM) along a cyclic transformation between the hot and the cold sources. The magnetic energy is transformed into mechanical energy via the magnetic forces and eventually into electrical energy through an electromechanical transducer. Firstly, we work-out the optimal size of the cantilever in order to achieve the self-oscillation of the MCM between the two heat sources. Eventually, using finite element calculations, we compare the efficiency of a piezoelectric transducer (PZT 5a) with that of a set of coils in order to convert the mechanical into electrical energy. The piezoelectrics and the coils recover 0.025% and 0.018% respectively of the available mechanical energy (116 mJ/cm3). The possible strategies to achieve a better performance are discussed in theconclusion.

A Thermal Energy Harvester Using LaFeSi Magnetocaloric Materials

“…The field source is an Halbach array, built using five NdFeB (1.5 × 1.5 × 10 mm 3 ) parallelepiped magnets. This configuration has been chosen to get a high well confined field [15]. The heat source is a heating electrical resistance while the cold reservoir is made with a water exchanger.…”

Energy Applications of Magnetocaloric Materials

“…The authors stated that the performance of the device was 60% greater than some comparable superlattice thermoelectric generators previously reported. A similar concept but with a theoretical study was recently presented by Ahmim et al Another similar concept, where the spring system is used instead of a cantilever, is shown in the Figure 17 .…”

“…Copyright 2007, AIP Publishing. Adapted under the terms of the Creative Commons Attribution 4.0 license . Copyright 2019, the Authors.…”

“…Schematic approximate example of the system, developed and tested by Ujihara et al, and theoretically studied by Ahmim et al Adapted with permission . Copyright 2007, AIP Publishing.…”

“…However, with the rapid development of caloric (ferroic) materials and technologies for refrigeration and air conditioning, caloric (ferroic) power generation is being revisited and prototype devices are being developed. Caloric power generation draws on specialized fields such as magnetocalorics (an aspect of thermomagnetics or pyromagnetics), electrocalorics (an aspect of pyroelectrics), and mechanocalorics (an aspect of thermoelastics) . Similar to refrigeration, multicaloric (multiferroic) power generation has also attracted research interest .…”