Experimental study of a miniature organic Rankine cycle unit using ocean thermal energy

•A miniature ocean thermal energy conversion(OTEC) unit is built and experimentally tested.•Experiments are conducted to explore OTEC performance under design and off-design conditions.•The OTEC unit produces a net power of 0.917 kW corresponding to a thermal efficiency of 1.46%.•Response surface method is used to evaluate how operating parameters affect OTEC performance.•Regression models are validated by ANOVA and comparing experimental results with model predictions.