Enhancing Photovoltaic/Thermal Energy Conversion Efficiency Using Spectral Splitting Techniques: A Comprehensive Review

Solar energy has been identified as an excellent renewable energy source; nonetheless, the photovoltaic/thermal (PV/T) system has the challenge of spectral mismatch, where the sun’s rays do not match the absorptivity of photovoltaics. There have been a considerable number of studies on splitting the sun’s spectrum into several regions to improve the efficiency of PV/T systems by optimizing both electrical and thermal energy. This paper provides a detailed review of spectral splitting techniques, including filters, dichroic mirrors, nanofluids, and concentration-based methods. There is also a thorough comparison of their performance in terms of electrical, thermal, and overall efficiency. Among the various studies on PV/T system efficiencies, it has been established that the nanofluid-based spectral splitter systems are the most efficient in converting energy, with a total efficiency of approximately 86.97%, which surpasses the efficiencies of the other two types: filters and concentrators. Also, it has been found that the nanofluid optical filtration system provides the most balanced electrical efficiency of up to [Formula: see text] alongside the best thermal efficiency ([Formula: see text]). In addition, the paper addresses long-term stability, optical losses, scalability, and techno-economics.