On the exploitability of thermo-charged capacitors

Abstract

Recently [Physics Letters A, 374, (2010) 1801] the concept of vacuum capacitor spontaneously charged harnessing the heat from a single thermal reservoir at room temperature has been introduced, along with a mathematical description of its functioning and a discussion on the main paradoxical feature that seems to violate the Second Law of Thermodynamics. In the present paper we investigate the theoretical and practical possibility of exploiting a such thermo-charged capacitor as voltage/current generator: we show that if very weak provisos on the physical characteristics of the capacitor are fulfilled, then a non-zero current should flow across the device, allowing the generation of potentially usable voltage, current and electric power out of a single thermal source at room temperature. Preliminary results show that the power output is tiny but non-zero.Comment: 23 Pages, 10 Figures. Physica A 390/6 (2011) 482 + Addendum (2013

The Demon in a Vacuum Tube

“…Given that and according to the analysis done in [2,5,6,7,11], even without the external static magnetic field, an equilibrium space charge eventually settles inside the bulb due to the thermionic emission. Under such an equilibrium, the electrode with lower work function ends up with an excess of positive charge with respect to the electrode with higher work function (which has an excess of negative charge).…”

“…In a series of recent papers [2,5,6,7], I have described in detail a vacuum spherical capacitor (a special kind of vacuum tube) that generates a macroscopic voltage between its spheres harnessing the heat from a single thermal reservoir at room temperature. It is a kind of demon that sorts electrons rather than molecules.…”

“…As a matter of fact, a quite solid and mature theoretical model of that already exists. As said before, I published a detailed physical/mathematical model of the thermo-charging process due to thermionic emission between electrodes with different work functions in [2,5,6,7]. Let me start saying something about the objections related to the voltage drop (and electric field) that allegedly would build up instantaneously between the free ends of two materials with different work functions just after being joined at one end, and that would prevent any thermionic emitted electron in the gap from spontaneously moving from low work function free electrode surface to high work function one.…”

A Note on Solid-State Maxwell Demon

“…This behavior does not match what happens in laboratory experiments and in the real world. [6][7][8][9] It is already well known that this is not what really happens (see the Volta effect [6,9]). When two metals with different work functions (and similarly, an n-and a p-semiconductor) are joined, the charge drift is only local and the charge displacement remains localized within the thin depletion layer, in equilibrium.…”

“…Far from the depletion region there is no free charge accumulation. A simple laboratory experiment with Cu and Zn plates and a gold-leaf electroscope can confirm such a behavior [6][7][8]. Only when the two metals are removed apart the charges, initially localized within the depletion layer, are free to spread across the surfaces of the metallic plates [7][8][9], satisfying electrostatic equipotentiality, see Fig.…”