Synergistic enhancement of heat transfer and thermal storage characteristics of shell and tube heat exchanger with hybrid nanoparticles for solar energy utilization

Abstract

Incorporating phase change material and nanoparticle into shell and tube heat exchangers is a common strategy to achieve thermal storage for solar energy utilization. However, the heat transfer and thermal storage characteristics of shell and tube heat exchangers with hybrid nanoparticles are limited. In this paper, twenty representative cases for three kinds of nanoparticles (Al2O3, TiO2, and CuO) and three sets of nanoparticle combination types (mono Nano-PCM, binary Nano-PCM, and ternary Nano-PCM) are considered. The effects of nanoparticle combination types and nanoparticle volume ratios on heat transfer and thermal storage characteristics of shell and tube heat exchangers are analyzed. The results show that the average melting rate of shell and tube heat exchangers with hybrid Nano-PCM is higher than mono Nano-PCM, which is enhanced by 2.3% with binary Nano-PCM and 5.2% with ternary Nano-PCM, respectively. The average energy storage and average energy storage rate of ternary Nano-PCM are the highest, followed by binary Nano-PCM and mono Nano-PCM, respectively. The maximum energy storage increment and enhanced average storage rate of shell and tube heat exchangers with ternary Nano-PCM are 1.13 kJ and 1.7%, compared to mono Nano-PCM. However, the average energy storage density of shell and tube heat exchangers with ternary Nano-PCM is the lowest with the maximum reduction rate of 20.22% compared to pure PCM. The results confirm that optimizing the configuration of hybrid nanoparticles can enhance the efficiency of solar thermal utilization.