Magnetic heat engines have been known about since 1889, but the success of gas engines has largely prevented research into this technology. Magnetic engines work by converting heat directly into electricity by taking advantage of temperature differentials to change the strength of magnetic fields. Changes in the magnetic field generate electricity.

The growth of semiconductor devices has increased interest in magnetic heat engines because circuits in such devices have to be cooled to stop the chips overheating. Only magnetic heat engines are responsive enough to cope with sudden changes in temperature. Mechanical fluid systems would be too slow or bulky to protect the chip.

Guruprasad's invention in Patent 5714829 has the advantage of being small, and having none of the moving parts that are usually found inside normal engines, which increases its reliability.

Guruprasad believes his devices are best suited for new types of fluid-free refrigerators, heating elements in cookers, and for the cooling of digital circuits.