Flue Gas Energy Recovery

The University of Idaho Steam plant switched to a biomass fired boiler in the 1980's which increased steam capacity and replace the existing coal and natural gas boilers. These boilers produce a large amount of waste flue gas heat that our team is tasked with recovering and using to produce electricity.

Problem Definition
Background

The Steam Plant:
 * The University of Idaho Steam plant is full of hot surfaces that constantly put out heat. Our teams goal is to capture this waste heat by utilizing Thermoelectric Generators (TEGs) to produce output power that charges 2 way radios at the steam plant.

Initial Design
Goals
 * Be able to be applied to a wide variety of surfaces
 * Maximize efficiency of the TEG by increasing the ΔT
 * Minimize impact to existing structure or surface it is applied to
 * Operate with little annual maintenance
 * Apply to surfaces with a Temperature that is steady state
 * Design an optimal way to provide the Cold side for the TEG

Specifications
 * Desired TEG Wattage output (estimate): 40W
 * Temperature range (based on applied surface):
 * 1.Wood boiler exhaust: T_out=278°F to 285°F
 * 2.Wood boiler flash hopper: T_out=500°F
 * 3.Wood boiler outlet: T_out=280°F to 300°F
 * 4.Wood boiler bottom ash hopper=250°F to 350°F
 * Q necessary=500 to 800 Watts

Proof of Concept
For our teams initial testing we where able to get some TEGs from a past senior design project, some old heatsinks, and a hotplate from the chemistry department here at the University of Idaho.

Final Design
The wiring diagram below shows how everything will be installed at the steam plant, how the modules are put together, how the battery charger is used, and TB3 and TB4 show the wires run for thermocouples hooked up to 1 module for monitoring temperature.

Document Archive
Meeting Minutes
 * [[Media:Minutes 9-15-16.pdf| September 15th 2016 ]]
 * [[Media:Minutes 9-21-16.pdf| September 21th 2016 ]]
 * [[Media:Minutes 9-28-16.pdf| September 28th 2016 ]]
 * [[Media:Minutes 10-5-16.pdf| October 5th 2016 ]]
 * [[Media:Minutes 10-12-16.pdf| October 12st 2016 ]]
 * [[Media:Minutes 10-19-16.pdf| October 19th 2016 ]]
 * [[Media:Minutes 11-2-16.pdf| September 2nd 2016 ]]

Papers

Schedule

Design Review