Thermal energy storage based (TES-based) reverse cycle defrosting control strategy optimization for a cascade air source heat pump

•Experiments were conducted to optimize the control of TES defrosting for CASHPs.•To regulate heat distribution, the LSC and HSC refrigerant flow rates were adjusted.•Optimization included changing the LSC compressor frequency and HSC EEV opening.•LSC compressor frequency of 90 Hz is recommended.•Reducing the HSC EEV opening is recommended.