A review of water heating systems: A Focus on hybrid technologies prospect in Nigeria

The rising energy demand necessitates a rapid transition to renewable energy and efficient technologies. The Nigerian household sector consumes enormous energy to meet domestic needs such as water heating. Furthermore, rising electricity costs hinders the commercial use of electric water heaters. As a result, energy users rely on conventional methods of heating water. In general, over-reliance on traditional water-heating systems have resulted in envi-ronmental degradation and public health crises. Adopting energy-efficient technologies may improve energy security, mitigate energy crises, reduce costs, and further optimize household energy consumption. This paper provides a comprehensive review of existing and emerging water-heating systems with a summary of recent innovations in water- heating systems. Var-ious types of hybrid and renewable water heating systems, as well as their configurations, are examined. In addition, relevant studies on different water-heating technologies are reviewed and classified according to their contribution, study type, and technology. The review findings are well articulated, and policy recommendations for solar water heating systems are made. This review's findings identify research gaps in the hybrid water-heating technology in Nige-ria. This survey provides insight into solar and hybrid solar systems as an alternative solution to fossil-fuel-based water heating systems.