Comprehensive review on the development of SAHP for domestic hot water

In this paper, a comprehensive review of the research works regarding the solar assisted heat pump system (SAHP) in the application of domestic hot water will be conducted, starting with the working principle, classification, theoretical analysis and demonstration samples. The overview of the research works was then analysed with respects to five categories, i.e., (1) integrated structure and individual components layout, sizing and optimisation; (2) thermal performance simulation and prediction; (3) laboratory based measurement compared against the modelling prediction; (4) long-term performance evaluation through real time and onsite measurement; and (5) economic and environmental assessment and social acceptance analyses. The opportunities, i.e. developing novel, economically-feasible, energy-efficient systems in combination with advanced technologies, conducting the real time and onsite measurement and assessing the energy, economic and environmental influences and social acceptance, applying standardisation method to design, manufacture, choose, test and utilise the appropriate system, and exploring energy policy and subsidy strategies for market expansion of SAHP, will be provided for the researchers and engineers relevant to this research field. The results of this research will be helpful in indicating the potential research areas for the overseas and domestic researchers, developing potential industries for the worldwide engineers, expanding the global solar market, and providing potential ways of saving energy and reducing carbon emission for the local governments.