The optimization and energy efficiency analysis of a multi-tank solar-assisted air source heat pump water heating system

This article undertakes an optimization study of a solar-assisted air source heat pump water heating system by harnessing the advantages inherent in a multiple water tank arrangement. The Hooke-Jeeves algorithm was adopted to optimize the system parameters. The optimization variables encompass pivotal parameters such as water tank volume, collector area, dip angle, azimuth angle and heat pump power, while the objective function is the annual value of life cycle cost. By research and analysis of the monthly power consumption, electricity cost, solar fraction, average coefficient of performance (COP) and annual value of carbon emissions of the single-tank, dual-tank, and triple-tank system, it is discovered that the triple-tank system exhibits superior performance in overall aspects. Compared to the pre-optimized version, it achieves an annual energy consumption reduction of approximately 3.9%, leading to a 22.5% decrease in electricity expenses. Furthermore, it brings a 5.2% reduction in the annual lifecycle cost and a 6.3% decrease in carbon emissions, while simultaneously improving exergy efficiency by 4.8%.