There exists a whole class of Direct Energy Conversion Generators in the literature, which, while they work in principle, do not exhibit the kind of efficiencies needed to compete with rotary machines or photovoltaics. A breakthrough with any one of them could end our dependence on oil and coal, and reduce the effects of Global warming.
The Nernst effect generator uses crossed magnetic and thermal fields to produce a voltage.
The Ferroelectric converter employs a capacitor with a special dielectric whose constant varies rapidly around its Curie Point.
The Thermomagnetic converter uses a magnetic material whose permittivity drops above its Curie Point. A variation of this concept employs a shunt made from a superconducting material that completely blocks any magnetic flux when it is in the superconducting mode via the Meissner Effect. This device is amazingly efficient but can only operate at the cold (low energy) levels of superconducting materials, so here’s not a lot of hope of it ever becoming a useful power source.
My work is another variation of the Thermomagnetic Generator which I’m calling a Ferromagnetic Generator. As it works at high temperatures, it can produce usable power levels. As it doesn’t require expensive and rare chemicals like the ferroelectric generator, it should be cheap and safe so people can have their own roof-top solar collector.
My companion website explains the theory and my work. (And yeah, a few asides about life and the frustrations of being a crazy inventor.) My hope is that others will see the generator’s possibilities and examine the ideas in more detail.