Fatigue life prediction and energy conversion efficiency evaluation of a photovoltaic-thermoelectric device subjected to time-varying thermal and wind hybrid loads

The photovoltaic-thermoelectric (PV-TE) device is one of the most promising pollution-free devices along with the booming demand for green electricity. The multilayered PV-TE device has poor interfacial mechanical performance and is subjected to complex cyclic loads. Thus, the interfacial stresses and crack propagation are investigated to deepen understanding of the interfacial fatigue failure mechanism of PV-TE device subjected to the time-varying thermal and wind hybrid loads. The continuity of thermo-electrical-mechanical coupled stress at the interface is fulfilled by employing the modified laminated plate theory. Equations of motion are derived by means of Hamilton's principle and Galerkin method. It is found that the thermally induced interlaminar shear stress is much larger than the wind-induced stress. The fatigue life varies linearly with wind speed and cold side temperature of the substrate layer. The fatigue life can be prolonged by reducing thickness of the TE leg and decreasing the efficiency temperature coefficient of the PV cell. A balance between the improvements of fatigue life and energy conversion efficiency of the device can be achieved by designing a reasonable thickness of PV cell. The fatigue life and energy conversion efficiency of the device without considering heat losses from PV cell are underestimated, especially at high wind speeds. The simple but useful expressions of fatigue life and energy conversion efficiency with respect to the wind speed and environment temperature are given to guide the engineering applications.