In the present study, we experimentally demonstrate the spectrally coherent and diffuse thermal emission by exciting magnetic polaritons in SiC metasurfaces fabricated by the focused ion beam technique. Spectral emittance characterized by using an infrared microscope coupled to a Fourier transform spectrometer clearly shows a wavelength-selective emission peak as high as 0.8. Numerical simulations including emittance spectra and contour plot of electromagnetic field distribution were carried out to verify and understand the underlying mechanism of magnetic polaritons. The metasurfaces were further shown to be direction and polarization independent. The results would facilitate metasurfaces for applications like radiative thermal management and infrared sensing.

The high operating temperatures of photovoltaic (PV) panels negatively affect both electrical efficiency and material degradation rate. Combining both a water-cooling-based photovoltaic/thermal (PV/T) system and a phase-change material (PCM) with/without low concentration (LC) represents a promising solution for boosting the overall energy conversion efficiency of the PV system. This approach needs to be evaluated in harsh weather where the PCM should have a high melting temperature. Therefore, this study experimentally investigates the performance of three PV cooling systems, namely PV-PCM, PV/T-PCM, and LCPV/T-PCM, compared to a reference PV without cooling, under the weather conditions of Riyadh. The results show that the PV/T-PCM attained the highest daily average electrical and overall efficiencies of 14.24% (5% increase) and 42.7%, respectively, compared to 13.56% electrical efficiency of the reference panel. The electrical efficiency of the PV-PCM was 13.64% due to inefficient natural cooling in the afternoon. The LCPV/T-PCM recorded the best performance during the two hours around noon, with an average increase in electrical power and efficiency of 11.06% and a maximum overall efficiency of 70%. Finally, the LCPV/T-PCM system can be only effectively used to support the higher demand for electricity and thermal energy around noon; otherwise, a new design configuration with low concentration is needed to establish a higher electrical efficiency in most hours of sunlight.