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The thermoelectric (TE) solar air collector, sometimes known as the hybrid solar collector, generates both thermal and electrical energies simultaneously. A double pass TE solar air collector has been developed and tested. The TE solar collector was composed of transparent glass, air gap, an absorber plate, thermoelectric modules and rectangular fin heat sink. The incident solar radiation heats up the absorber plate so that a temperature difference is created between the thermoelectric modules that generate a direct current. Only a small part of the absorbed solar radiation is converted to electricity, while the rest increases the temperature of the absorber plate.The ambient air flows through the heat sink located in the lower channel to gain heat.The heated air then flows to the upper channel where it receives additional heating from the absorber plate. Improvements to the thermal and overall efficiencies of the system can be achieved by the use of the double pass collector system and TE 2 technology. Results show that the thermal efficiency increases as the air flow rate increases. Meanwhile, the electrical power output and the conversion efficiency depended on the temperature difference between the hot and cold side of the TE modules. At a temperature difference of 22.8°C, the unit achieved a power output of 2.13 W and the conversion efficiency of 6.17%. Therefore, the proposed TE solar collector concept is anticipated to contribute to wider applications of the TE hybrid systems due to the increased overall efficiency.

Thermoelectric generation capable of delivering reliable performance in the low-temperature range (<150 °C) for large-scale deployment has been a challenge mainly due to limited properties of thermoelectric materials. However, realizing interdependence of topological insulators and thermoelectricity, a new research dimension on tailoring and using the topological-insulator boundary states for thermoelectric enhancement has emerged. Here, we demonstrate a promising hybrid nanowire of topological bismuth telluride (Bi2Te3) within the conductive poly­(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) matrix using the in situ one-pot synthesis to be incorporated into a three-dimensional network of self-assembled hybrid thermoelectric nanofilms for the scalable thermoelectric application. Significantly, the nanowire-incorporated film network exhibits simultaneous increase in electrical conductivity and Seebeck coefficient as opposed to reduced thermal conductivity, improving thermoelectric performance. Based on comprehensive measurements for electronic transport of individual nanowires revealing an interfacial conduction path along the Bi2Te3 core inside the encapsulating layer and that the hybrid nanowire is n-type semiconducting, the enhanced thermoelectricity is ascribed to increased hole mobility due to electron transfer from Bi2Te3 to PEDOT:PSS and importantly charge transport via the Bi2Te3–PEDOT:PSS interface. Scaling up the nanostructured material to construct a thermoelectric generator having the generic pipeline-insulator geometry, the device exhibits a power factor and a figure of merit of 7.45 μW m–1 K–2 and 0.048, respectively, with an unprecedented output power of 130 μW and 15 day operational stability at ΔT = 60 °C. Our findings not only encourage a new approach to cost-effective thermoelectric generation, but they could also provide a route for the enhancement of other applications based on the topological nanowire.

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