Background: Solar water heating is a highly sustainable method of extracting thermal energy from the sun for domestic and industrial use. In residential buildings, thermal energy from a Solar Water Heater (SWH) can be used to heat spaces, shower, clean, or cook, either alone or in combination with conventional heating systems such as electricity- and fossil-fuel-based heaters. In the industrial sector, SWHs can be used in various high-temperature fluid processes, including chemical processing, manufacturing, power generation, and construction. Despite the technological advancements in water heating systems, there are still some significant technical and economic challenges that limit their widespread adoption and commercialization. Despite their potential to revolutionize the industry, these systems remain in the shadows of unsustainable water heating solutions. Main body of the This paper reviews recent selected publications on the technical and techno-economic aspects of solar water heating technology. The discussions include the effects of some parameters and components on the overall thermal efficiency of the SWHs as well as the techno-economic prospects of the technology. In addition, the paper provides the existing research gaps and recommendations for future research directions. Short conclusion: The present review paper is unique because it condenses the recent studies carried out on both the technical and techno-economic aspects of the SWHs. It provides a comprehensive framework for interested readers and researchers to gain insights into the technical and economic status of SWHs. However, it is not an exhaustive study. The information presented can aid researchers in conducting further research on the subject, as well as understanding the future of SWHs.

The fusion of the circular economy and industrial symbiosis has several advantages from an economic and developmental standpoint. Cooking energy security issues in Africa can partly be solved by the utilization of waste resources in energy technology decisions such as briquette. However, one of the limitations associated with waste-based briquettes has been identified as a reduction in efficiency when stored for a long period of time under varied storage conditions. The aim of this study was to ascertain the effects of storage time and exposure on the calorific value and mechanical characteristics of a waste-based composite briquette made from oil palm shell and decanter cake after 180 days of storage. The calorific value decreased by 12.99% and 31.40%, respectively, for sealed packaged storage and open-air storage. On the 180th day of the experiment, the packaged storage and the open-air storage registered 1000.48 kg/m³ and 870 kg/m³, 72.34% and 100%, 712% and 895%, and 118% and 143% for relaxed densities, shatter indices, resistance to impact, and hygroscopic properties respectively. Manufacturers within West Africa can adopt the findings in this study as a guide for their processes.

The fusion of the circular economy and industrial symbiosis has several advantages from an economic and developmental standpoint. Cooking energy security issues in Africa can partly be solved by the utilization of waste resources in energy technology decisions such as briquetting. However, one of the limitations associated with waste-based briquettes has been identified as a reduction in efficiency when stored for a long period of time under varied storage conditions. The aim of this study was to ascertain the effects of storage time and exposure on the calorific value and mechanical characteristics of a waste-based composite briquette made from oil palm shell and decanter cake after 180 days of storage. The calorific value decreased by 12.99% and 31.40%, respectively, for sealed packaged storage and open-air storage. On the 180th day of the experiment, the packaged storage and the open-air storage registered 1000.48 Kg/m³ and 870 Kg/m³, 72.34% and 100%, 712% and 895%, and 118% and 143% for relaxed densities, shatter indices, resistance to impact, and hygroscopic properties respectively. Manufacturers within West Africa can adopt the findings in this study as a guide for their processes.