Transient analysis in a plate heat exchanger is an effective method to study its dynamic behavior. It can extract various performance parameters of a heat exchanger, such as heat transfer coefficient, individual channel flow rate, and time constant. The present work studied the transient response of cold-side water temperature in a U-type, chevron-corrugated countercurrent plate heat exchanger with the step changes of the inlet flow rate of hot-side water. During the experimental temperature transients, the time constants varied from69.70 to 95.72 s. The calculated overall heat transfer coefficients from the transient experiment were in the range from 1387.99 to 1925.51 W m^-2 °C^-1. The transient responses of outlet temperatures were optimized through atime-domain model formulation with parameter estimation techniques. The overall heat transfer coefficients were estimated from the optimized simulations based on a simplex optimization and a nonlinear programming solver. The simplex optimization method underpredicted the experimental transient response with lower values of the predicted heat transfer coefficient. The nonlinear programming solver predicted the transient response precisely with lower values of square sum error.