Experimental study and validation of heat transfer correlations for plate-fin heat exchangers using cyclopentane as working fluid

• System-level ORC experiments were performed using cyclopentane as the working fluid. • Heat transfer correlations for plate-fin heat exchangers with cyclopentane were developed. • Dynamic simulations verified the correlations with deviations less than 7%. As a key component of the Organic Rankine Cycle (ORC) system, the heat exchanger is responsible for the conversion of thermal energy and directly affects the dynamic behavior of the system. Appropriate heat transfer correlations are essential for both heat exchanger design and dynamic behavior analysis. Owing to its high vapor pressure and temperature, cyclopentane is a promising working fluid for ORC systems. However, studies on heat transfer correlations for cyclopentane-based heat exchangers remain limited. This study conducted experiments on an ORC system. Based on steady-state experimental data, a particle swarm optimization (PSO) algorithm was applied to calibrate and validate heat transfer correlations for cyclopentane plate-fin heat exchangers, and applicable correlations was proposed. Further validation was performed using dynamic modeling combined with dynamic experimental data. The results indicate that the proposed correlations achieve high prediction accuracy, with mean relative deviations of cyclopentane outlet temperature below 7% and pressure deviations below 1.5% for both the plate-fin evaporator and recuperator. This work provides valuable guidance for the design and dynamic analysis of cyclopentane-based plate-fin heat exchangers.