Recent developments in solar water heaters and solar collectors: A review on experimental and neural network analyses

Solar water heaters (SWHs) and solar collectors (SCs) are crucial renewable energy technologies that have developed attractiveness in recent years, as a result of their several benefits over traditional energy sources. To further enhance their thermal performances and efficiencies, researchers and engineers have implemented various modifications in the systems. The modifications include integrating SWHs with storage collectors, combining SWHs with photovoltaic cells, integrating thermosyphon and twisted tapes, enriching collectors with nanofluids, phase change materials and using different types of evacuated tube SCs. Furthermore, improvement in materials, design and operating conditions have led to performance enhancement of parabolic trough and linear Fresnel SCs. In addition, the modifications have enabled SWHs to be more cost-effective and resulted to efficient SCs, making them increasingly attractive for several commercial, industrial and residential applications. Recent studies are expected to enhance their performance and economic suitability, making them more viable and sustainable energy devices. Hence, an elaborated discussion on various state-of-the-art modifications in SWHs and SCs to enhance their efficiencies and the application of artificial neural network (ANN) in SWHs and SCs is reported in this comprehensive review, which is lacking in the earlier studies. This compendious article provides the techniques for enhancing both SWHs and SCs to leverage renewable, abundantly available, sustainable and environmentally friendly solar energy. It also expatiates on their future considerations, as a scope for further works and towards advancement in clean energy devices.