Performance Analysis and Optimization of a Cascade PCM Cold Storage Heat Exchanger

To improve the heat transfer performance and the energy quality of cold storage devices,a cascade phase change cold storage heat exchanger was designed.A mathematical model for the heat exchanger was developed based on the enthalpy method to simulate its heat transfer process,and the model was validated by experimental results.Furthermore,an optimization analysis of the heat exchanger was made according to such indicators as charge time and cold exergy efficiency,under an operating condition of 7 [degrees]Cinlet water at an average speed of 1mm/s.The results show that the heat exchanger has the best performance when three types of phase change materials,with phase change temperature combination of 12.3 [degrees]C,13 [degrees]C and 13.3[degrees]C,are arranged by a mass ratio of 1:1:1.Under this condition,its exergy efficiency is 72.2% and its charge time is 160.4min,which means the exergy efficiency and cold storage rate increase by 1.2% and 1.7% compared with the single phase change cold storage device with a