Kelvins Relations

When we derived the formulas for the performance of thermocouples, we stated that the Peltier coefficient, n, was equal to aT. We will now prove this assertion. In addition, in developing the thermocouple formulas, we failed to introduce the Thomson effect discussed in the preceding subsection. Here, we will justify this omission. Heat flows from the hot source to the couple at a rate t'Tc 1

jth 2

^William Thomson was knighted Lord Kelvin in 1866, mainly in recognition of his work in transatlantic telegraphy.

Notice that in this case we have included the Thomson heat convection. The Thomson coefficients of arms A and B are, respectively, ta and tb .

We will consider a hypothetical thermocouple that has neither electric resistance nor heat conductance. It is a reversible device with no losses. Since both A and R are zero, r tc

In the same manner, heat flows from the sink to the couple at a rate

As there are no losses, the power, VLI, delivered to the load is equal to the total heat power input, PH + PC. Moreover, because of the absence of resistance in the thermocouple, the load voltage, VL, is equal to the open-circuit voltage, Voc.

r Th

Pe

Pc

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Solar Stirling Engine Basics Explained

Solar Stirling Engine Basics Explained

The solar Stirling engine is progressively becoming a viable alternative to solar panels for its higher efficiency. Stirling engines might be the best way to harvest the power provided by the sun. This is an easy-to-understand explanation of how Stirling engines work, the different types, and why they are more efficient than steam engines.

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