Solar generator heat absorber

How does a solar absorber work?

The copper substrate of the solar absorber serves as a heat concentrator by conducting heat laterally to the thermoelectric elements (Fig. 1d), whereas the bottom copper plates serve as electrodes, heat spreaders, and radiation shields that reduce radiation losses from the rear side of the selective absorber.

Can a stretchable solar absorber be used as a thermoelectric generator?

A facile method to fabricate a mechanically robust, stretchable solar absorber for stretchable heat generation and an enhanced thermoelectric generator (TEG) is demonstrated.

How does a solar absorber reduce heat loss to the environment?

During the heat-up phase, sunlight incident on the device causes it to heat up at a rate of around 2 K/min. Radiation heat losses to the environment are minimized by a spectrally selective absorber material, which has a high solar absorptance αsolar of 0.92 and a low thermal emittance ϵthermal of 0.08 (Supplementary Fig. 8).

What is the thermal absorptance of a solar absorber?

The copper side of the solar absorber is in both thermal and electrical contact with the thermoelectric elements (Fig. 1). The selective surface has a specified solar absorptance of 94.4% and a thermal emittance of ~5% at 100 °C (Supplementary Information).

How much power does a solar absorber produce?

The larger thermal radiation heat loss of the solar absorber limits the peak STEG efficiency to 7.6% and the peak power output to close to 0.3 W at a solar irradiance of ∼ 38 kW m −2 (Fig. 3a,b). The absorber operating temperature at peak STEG performance is approximately 420 ∘ C.

Why do CNT solar absorbers produce heat?

The most plausible reason for this is that water reduces the temperature on the cold side. CNT solar absorbers store solar heat on the hot side and generate thermoelectric power on the basis of the significant temperature differential.