• The microchannel of heat exchanger is optimized based on the configuration theory of thermal resistance and flow resistance minimization. • The heat transfer characteristics and flow characteristics of the optimized structure and the comparative structure under different conditions are studied. • Based on the efficiency evaluation criteria, the comprehensive heat transfer performance of the designed heat exchangers with different structures was evaluated. • The comprehensive efficiency of the optimized structure is 2.81 times that of the contrastive structure in the research range. Under the same working conditions, the optimal design of the heat exchanger is to have the highest heat transfer efficiency with the lowest pump power consumption. In order to achieve this goal, this paper optimized the microchannel element and microchannel array structure of a plate heat exchanger based on the configuration theory of maximum heat transfer efficiency and minimum flow resistance. At the same time, three contrast structures were designed under the same constraints. The heat and mass transfer performance of the optimized structure (OPTS) and the three comparison structures (CS) were studied through experiments. Three evaluation criteria were used for comparative analysis, namely, heat transfer coefficient per unit volume, pump power consumption and comprehensive efficiency evaluation criteria. The experimental results show that, considering the amount of heat transfer and pump power consumption, the OPTS has the best comprehensive heat and mass transfer performance. Within the scope of the study, the comprehensive efficiency of the OPTS can be up to 2.81 times of the CS. [ABSTRACT FROM AUTHOR]