Ultrasonic thermophysical enhancement of a novel nanodoped vapour compression fluid for high cooling efficiency

•Ultrasonication of nano-Cu/Si doped compressor oil was done at 40–120 kHz.•Copper and silicon nanoparticles of varying concentrations were used.•The CuNP and SiNP-oils sonicated at 120 Hz, gave cooling effects of −11 and −7 °C respectively.•The best cooling effect and performance were recorded for the 1 M CuNP-oil.•The inherent enthalpies and entropies suggest optimal heat conservation for the 1 M CuNP-oil.