US 4,125,122 A · Direct energy conversion device

Abstract

A method and apparatus are described for directly converting heat to electricity within an array of thermoelements and heat pipes. The thermoelectric generator contains two conduits for two fluid streams, and a plurality of thermal bridges connecting points in both fluid streams, placing them in an overall counterflow heat exchange relationship. Each thermal bridge comprises at least one heat exchange surface with the first fluid stream, at least one heat exchange surface with the second fluid stream and at least one heat pipe, delivering heat to and/or from the thermoelectric element. The rapid heat delivery capability of the heat pipes, in combination with the counterflow heat exchange relationship between the two fluid streams within the generator, are responsible for the simultaneous considerable improvement of efficiency and power density of the generator.

Claims11

Dependent claims

A method for directly converting heat to electricity in an electric generator using a plurality of thermoelectric elements and heat pipes comprising the steps of

heating a first fluid stream at a heat source and directing said first fluid stream toward a heat sink;
directing a cool second fluid stream toward said heat source;
locating a plurality of thermal bridges effectively thermally insulated from each other operatively between the first and second fluid streams to effectively place the first and the second fluid streams in counterflow relationship for the direct conversion of heat to electricity by said thermal bridges;
heat exchanging one end of the plurality of thermal bridges with the first fluid stream at successively lower temperatures thereof;
and
heat exchanging respectively the other ends of the thermal bridges with the second fluid stream at respectively successively lower temperatures thereof;
whereby the temperature gradients inside the thermoelectric elements are generally parallel to the direction of the overall temperature drop of the fluid streams for maximization of efficient generation of electricity with high power density.

4 more elements

An electric generator having a hot end and a cool end wherein electricity is produced by the direct conversion of heat to electricity with thermoelectric elements and heat pipes comprising

means for producing a heated first fluid stream flowing to the cool end of the generator;
means for producing a cool second fluid stream flowing to the hot end of the generator;
two conduits containing the first and the second fluid streams respectively;
means for producing a plurality of thermal bridges formed of operatively coupled heat pipes and thermoelectric elements;
said thermal bridges being operatively coupled in heat exchange relationship with said first and second fluid streams to effectively place said streams in counterflow relationship;
said thermal bridges having each one end thereof in heat exchange relationship with the first fluid stream at respectively and successively lower temperatures thereof;
wherein respectively other ends of said thermal bridges are placed in heat exchange relationship with the second fluid stream at respectively successively lower temperatures thereof;
and with successive thermal bridges being effectively thermally insulated from each other
whereby said electric generator has temperature gradients across the thermoelectric elements in generally parallel relationship with the overall temperature gradient of the fluid streams for an efficient generation of electricity with a high power density.

6 more elements

Dependencies are inferred from the claim text.

Direct energy conversion device

Life of this patent

Direct energy conversion device

Life of this patent

Abstract

Claims11