Optimization of a cylindrical thermomagnetic engine for power generation from low‐temperature heat sources

Abstract

A low-grade heat source can be used as an operating fuel to run a thermomagnetic heat engine (TME), whose performance is determined by the interaction of the magnetic field between a permanent magnet and a thermomagnetic material used in the engine. In this paper, we present a cylindrical TME to scavenge low-grade thermal energy and its eventual conversion into mechanical energy. Various models were investigated to optimal performance via COMSOL Multiphysics 5.4, especially in terms of axial torque generation, where experimental validations were made as appropriate. Finally, an optimized model was selected to develop a prototype of the TME. Using hot and cold water at a temperature of 65 C and 22.5 C, the TME produced an average torque and mechanical power of 81.73 N mm and 1.17 W, respectively. The thermal to mechanical conversion efficiency was calculated to be 0.104%. The present mathematical model can be effectively used to design and fabricate a commercially applicable TME in reality, and this, in turn, will allow for the development of a practicable and efficient TME for the exploitation of lowgrade thermal energy.

Design and operation of a thermomagnetic engine for the exploitation of low‐grade thermal energy

“…Rahat used a hybrid coupling of EMG and TENG to produce electricity from the thermomagnetic generator. 27,28 Zeeshan utilized a different design and coupled the thermomagnetic generator with a TENG and EMG hybrid orientation to generate power. [29][30][31] Both of these designs can utilize heat from very low-grade thermal reservoirs to produce electricity.…”

“…Several studies have been conducted to harvest electrical energy from this model of thermomagnetic heat engine. Rahat used a hybrid coupling of EMG and TENG to produce electricity from the thermomagnetic generator 27,28 . Zeeshan utilized a different design and coupled the thermomagnetic generator with a TENG and EMG hybrid orientation to generate power 29‐31 .…”

Magnetic Simulation of a Thermomagnetic Motor Based on an Analytic Model

“…While this approach is useful for many applications, it has several limitations [2] that must be taken into account for more accurate magnetic field simulation. Recent years have witnessed a surge in research on TMD [3], [4], [5], with numerical modeling and simulation techniques playing a crucial role in advancing the understanding of their performance and potential applications. Trapaneze (2011) modeled the stator and rotor of a TMD [6] using direct-axis and quadrature-axis theory of electromagnetic machines [7] , while Alves (2013) [8] propose a magnetic model based on the magnetic circuit procedure developped by Furlani [9].…”

“…Gabrielyan (2015) used ANSYS software to simulate the magnetic attraction force between soft magnetic material and a permanent magnet in a TMD [11]. Similarly, Kaneko [12] (2019) and Ahmed [5] (2021) used COMSOL Multiphysics to perform simulations related to magnetic system of thermomagnetic motors. Existings approachs are based either on experimentation or numerical simulations tools.…”