Portable combustion device utilizing thermoelectrical generation

• US 8,297,271 B2
• Filed: 10/06/2009
• Issued: 10/30/2012
• Est. Priority Date: 10/07/2008
• Status: Active Grant

• Current Assignee: BioLite Inc.
• Original Assignee: Biolite LLC
• Inventors: Cedar, Jonathan M., Drummond, Alexander H.
• Primary Examiner(s): McAllister, Steven B
• Assistant Examiner(s): MASHRUWALA, NIKHIL P
• Application Number:
  US12/574,647
• Publication Number:
  US 20100083946A1
• Time in Patent Office: 1,120 Days
• Field of Search: 126/25.B, 126/25.A, 126/9.R, 126/15.A, 126/501, 110/1.F
• US Class Current: 126/25.B
• CPC Class Codes: F23B 20/00 Combustion apparatus specially adapted for portability or transportability
• CPC Class Codes: F23B 60/00 Combustion apparatus in which the fuel burns essentially without moving
• CPC Class Codes: F23M 2900/13003 Energy recovery by thermoelectric elements, e.g. by Peltier/Seebeck effect, arranged in the combustion plant
• CPC Class Codes: F24B 1/00 Stoves or ranges
• CPC Class Codes: F24B 5/026 Supply of primary and secondary air for combustion
• CPC Class Codes: H10N 10/13 characterised by the heat-exchanging means at the junction
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

This invention provides a portable combustion device that provides a cleaner combustion, reduces the kindling period, and provides a more efficient overall combustion through the use of a fan that directs a predetermined volume of airflow over the combustible fuel—typically wood or similar cellulose-based biological solids. The combustion device has a combustion chamber into which the fuel source is placed for combustion. Mounted to the side of the combustion chamber is a housing that encloses the TEG, which generates an electrical output based on a difference in temperature on opposing sides. Mounted onto the TEG housing and protruding into the combustion chamber through a small passageway is a heat-conducting probe and heat-conducting probe base unit. The opposing side of the TEG is also in contact with a heat sink to remove heat from the TEG device through interaction with ambient air that passes over the vanes from a port located along the side of the TEG housing. A motor and fan near the heat sink to draw air away the heat sink and aid in the cooling of the heat sink, and force air onto the combusting fuel through a plurality of peripheral ports that connect with an air space located between the inner and outer walls of the combustion chamber.

Claims

1. A combustion device comprising:

a combustion chamber comprising an inner wall defining a combustion space that contains, and is in communication with, a biomass fuel source and an outer wall having a side-mounted interface port allowing access of airflow into the combustion space enclosed within the outer wall;

a thermoelectric generator (TEG) located outside the outer wall and including at least one thermally connected heat-conducting probe on a hot side thereof that extends into the combustion space, the TEG further including a heat sink thermally connected to a cold side thereof; and

a motorized airflow driver electrically connected to the TEG and constructed and arranged to drive air from an ambient source, over the heat sink and into the interface port so as to generate a positive pressure in the combustion space;

wherein the TEG is provided in a TEG housing having a vent thereon upstream from and confronting the heat sink and an airflow interface remote and downstream from the motorized airflow driver, the airflow interface being constructed and arranged to engage the interface port on the outer wall.

2. The combustion device as set forth in claim 1 further comprising an inner wall surrounding the combustion chamber and surrounded by the outer wall, the inner wall defining an airspace with respect to the outer wall, the inner wall including a port structure that provides access for passage of the airflow from the interface port to the combustion chamber.

3. The combustion device a set forth in claim 2 wherein the port structure defines a plurality of ports located about at least a portion of a perimeter of the inner wall adjacent to at least one of an upper end and a lower end of the combustion space.

4. The combustion device as set forth in claim 1 further comprising a plurality of folding legs, and wherein the heat-conducting probe is located at an acute angle with respect to a horizontal plane defining a supporting surface for the legs, at least one of the legs constructed and arranged to move between an engaged and a disengaged orientation with respect to the TEG housing so as to selectively enable engagement and disengagement, respectively, of the TEG housing from the outer wall.

5. The combustion device as set forth in claim 1 wherein the TEG housing is constructed and arranged to be stored within the combustion space.

6. The combustion device as set forth in claim 1 wherein the TEG housing includes a draft located adjacent to the airflow interface so as to provide ambient air to the TEG housing at a location remote from the vent.

7. The combustion device as set forth in claim 6 wherein the draft is adjustable to vary airflow passing therethrough.

8. The combustion device as set forth in claim 1 further comprising a heat shield that extends around at least a portion of the outer wall.

9. The combustion device as set forth in claim 2 wherein the inner wall and the outer wall each define a pot shape with an enclosed bottom and wherein an upper edge of the outer wall is sealed against an outer edge of the inner wall to seal the airspace.

10. The combustion device as set forth in claim 9 wherein the upper edge of the outer wall engages a standoff with slots so as to allow air to pass therethrough when a cooking surface is rested upon the standoff.

11. The combustion chamber as set forth in claim 1 wherein the combustion space is constructed and arranged to receive fuel through at least one of a side port and a top opening.

12. The combustion space as set forth in claim 1 further comprising an energy storage circuit operatively connected to the TEG so as to store energy generated by the TEG.

13. The combustion device as set forth in claim 12 wherein the energy storage circuit is operatively connected to a connector constructed and arranged to electrically connect an electronic or electrical device.