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Project Goal:

To design and fabricate test equipment to accurately and easily determine efficiency and electrical performance of thermopiles under an imposed temperature gradient. The device must withstand vacuum, apply axial load, and display and record relevant data.

What is a Thermopile?:

A thermopile is a thermoelectric device. It converts heat energy into electrical energy. To do this it relies on two thermoelectric effects, the Seebeck effect and the Peltier effect. When an isolated conductor is exposed to a temperature gradient a voltage is set up in the material, this is known as the Seebeck effect. When two conductors of different composition are connected there is a voltage set up in each, but the voltage realized by each is different, thus there is a change in voltage across the material. When two conductors are connected under a temperature gradient a voltage is set up and current flows through the material. The opposite is also true, when current runs through two connected conductors a temperature gradient is setup up across the conductors. Those are the underlying effects of a thermopile. To further increase the output power of a thermopile many pairs of conductors are connected in series to create a larger change in voltage.

Project Significance:

The purpose of this project is to aid in data acquisition to characterize thermopiles more easily for use in applications in which heat scavenging is important. 

Required Specifications:

General

Specific

Performance

Measuring Electrical Characteristics

Open circuit voltage

Load resistance

Internal impedance

Load Voltage

As accurately as possible

Determine efficiency

Measure heat fluxes

Measure/calculate power output

Calculate an efficiency

The heat flux and temps on both ends of the thermopile must be measured and recorded.

As accurately as possible

Apply load

Apply axial load

Load must be self-centering

Variable axial load, up to 300 lbs, applied to thermopile.

Must be controlled by software.

The load must be self centering to the extent that it does chip or damage the edges.

Display and Record Data

Measure and record relevant data in Excel

Testing in Vacuum

Evacuate chamber before testing

System must withstand repeated application of vacuum

29” Hg or greater Vacuum

No system damage