Flue Gas Energy Recovery

The steam plant at the University of Idaho has a large amount of waste heat that is expelled from many different surfaces. This is a common issue that occurs in many different power plants and industrial settings. Our solution is to capture a portion of this waste heat by utilizing Thermoelectric Generators (TEG). This is accomplished by achieving a temperature difference across the TEGs surfaces. As the ΔT across the TEGs increases, the power generation also increases. Flared pin heat sinks and electric fans are used to attain this temperature difference. Therefore, heat that would normally be wasted is now turned into power used 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
Papers

Schedule

Design Review