Generation of electrical power

DETAILED DESCRIPTION This invention arises from a radical departure from prior-art thinking that to maintain a substantial temperature difference between the hot and cold junctions of a thermoelectric element, the length of the wire components or couples of the element should be high.
It has been realized in arriving at this invention, that, in fact, the length of these components has substantially no effect on the power output of a thermoelectric element.
The power output of a thermoelectric element is given by the equation: ##EQU1## where: P is the power output, E is the open circuit voltage of the element, R is the resistance of the element.
##EQU2## where: P is the resistivity of the wire components of the element, l is the length of the wire components, A is the cross-sectional area of the wire components.
Then: ##EQU3## That is: P varies inversely as the length.
The heat loss by longitudinal heat flow through a thermoelectric element is given by: ##EQU4## where: H is the heat loss, K is the conductivity of the wire components, .
DELTA.
T is the difference between the hot and cold junction.
##EQU5## where .
alpha.
is the seebech coefficient This ratio is independent of the length.
No appreciable advantage is then achieved by use of thermoelectric elements having long wire components as taught by the prior-art.
The heat flow H of equation (5) is the heat conducted through the thermoelectric wires longitudinal of the element.
Where the elements are wound in spirals of otherwise layered, this is not the only conductive heat loss.
Heat also flows laterally through the elements from layer to layer.
The layering in prior-art heat-to-electricity converters results not alone from the prior-art view that the wire components must be long.
it is also a prior-art teaching that the overall voltage output of the thermoelectric converter should be high.
This output is given for N thermocouples in series, by: V = NE .
DELTA.
T (6) where: V is the total voltage.
Where V is to be 6 volts, as many as 1,200 elements in series are required