Development and multi-objective optimization of a solar-powered hybrid aerator for aquaculture

Aerator is a crucial equipment in aquaculture production that accounts for over 60 % of equipment energy consumption. So far, two major challenges - high energy consumption and low oxygen mass transfer efficiency, still have not been resolved. To address these issues, this study designed a hybrid energy-saving aerator integrating solar power and conventional power supply. A multi-objective optimization algorithm was employed to analyze the influence of parameters such as aerator rotational speed and impeller submergence depth on dissolved oxygen (DO), diffusion efficiency and energy consumption. In this manner, the optimal combination of rotational speed and impeller submergence depth can be determined. Experimental results showed that under the optimal operating conditions (rotational speed of 90 rpm, impeller submergence of 0.10 m), the standard oxygen transfer rate (SOTR) reached 1.17 kg/h, with the standard aeration efficiency (SAE) of 1.74 kg/(kWh), representing a 32 % improvement compared to the YC-0.75 two-blade waterwheel aerator. Spatial DO distribution analysis indicated that the average DO concentration in the core area (0–10 m) was 8.96 mg/L, and it remained at 6.81 mg/L at 20 m, both meeting the aquaculture safety threshold of 5 mg/L. The hybrid power supply system prioritized solar energy utilization, achieving a daily power saving of 2.87 kWh, annual savings of 1047.55 kWh, and an energy-saving rate of 35.6 %. These findings provide theoretical support for the intelligent and low-carbon development of aquaculture equipment.