Thermomagnetic motors (also known as Curie wheels, Curie-motors and pyromagnetic motors) convert heat into
kinetic energy
In physics, the kinetic energy of an object is the energy that it possesses due to its motion.
It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acc ...
using the
thermomagnetic effect,
i.e., the influence of temperature on the magnetic material
magnetization.
Historical background
This technology dates back to 19th century, when a number of scientists submitted patents on the so called "pyro-magnetic generators". These systems operate in a magnetic Brayton cycle, in a reverse way of the
magnetocaloric refrigerators.
Experiments have produced only extremely inefficient working prototypes,
[
] however,
thermodynamic
Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws of the ...
analysis indicate that thermomagnetic motors present high efficiency related to
Carnot efficiency for small temperature differences around the magnetic material
Curie temperature
In physics and materials science, the Curie temperature (''T''C), or Curie point, is the temperature above which certain materials lose their permanent magnetic properties, which can (in most cases) be replaced by induced magnetism. The Cur ...
.
The thermomagnetic motor principle has been studied as a possible actuator in
smart material
Smart materials, also called intelligent or responsive materials, are designed materials that have one or more properties that can be significantly changed in a controlled fashion by external stimuli, such as stress, moisture, electric or magnetic ...
s, being successful in the generation of electric energy from ultra-low
temperature gradients.
See also
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Thermomagnetic convection Ferrofluids can be used to transfer heat, since heat and mass transport in such magnetic fluids can be controlled using an external magnetic field.
B. A. Finlayson first explained in 1970 (in his paper "Convective instability of ferromagnetic flu ...
References
*
Electric motors
Magnetic devices
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