Influence of carbon nanotubes (CNTs) on nucleate pool boiling heat transfer characteristics of refrigerant-oil mixture was investigated experimentally. Four types of CNTs with the outside diameters from 15 nm to 80 nm and the lengths from 1.5 μm to 10 μm were used in the experiments. Test conditions include CNTs mass fractions in the CNTs nanolubricant from 0 to 30 per cent and CNTs nanolubricant mass fractions from 0 to 5 per cent. The experimental results indicate that the presence of CNTs enhances the nucleate pool boiling heat transfer coefficient of R113-oil mixture by a maximum of 61% under the present test conditions. For fixed CNTs physical dimension

the enhancement range changes from 27%~59% to 23%~55% when CNTs nanolubricant mass fraction increases from 1% to 5%; the enhancement range changes from 27%~59% to 33%~61% when CNTs mass fraction in the CNTs nanolubricant increases from 20% to 30%. A correlation for predicting the nucleate pool boiling heat transfer coefficient of refrigerant-oil mixture with CNTs is proposed

and it agrees with 96% of the experimental data within a deviation of ±10%.