Geometry effect of phase change material container on waste heat recovery enhancement

• Main Authors: Qin, Zhen, Ji, Chenzhen, Low, Zheng Hua, Tong, Wei, Wu, Chenlong, Duan, Fei
• Other Authors: School of Mechanical and Aerospace Engineering
• Format: Article
• Language: English
• Published: 2023
• Subjects: Engineering::Mechanical engineering; Phase Change Materials; Storage Container Geometry
• Online Access: https://hdl.handle.net/10356/164667
• Institution: Nanyang Technological University

Waste heat recovery from industrial exhaust gases is a key method to reduce fuel consumption and improve system energy efficiency. Phase change materials (PCMs) are one of the major media in the waste heat storing and recovering processes. The PCM container geometry is a crucial design factor but attracts less attention for its effect on the PCM melting and heat storage operation. This study simulates the melting behaviour and heat storage performance in the PCM storage containers with the same cross area but different configurations with the rectangular shape and ones with concave folded sidewalls and protruding folded sidewalls. The geometry variation on PCM containers influences both the contact area with the hot airflow and natural convection in the melting phase of PCMs. The three-dimensional transient modelling indicates that the natural convection currents enhance the PCM melting and thermal storage rates. The PCM container design angle, α, shows a remarkable impact on the natural convection strength, PCM melting time, and energy storage rate. The protruding-shaped container with α at 133.8∘ presents the least melting time of 4,645 s, reducing 24.9% of the melting time in comparison to the rectangular chamber as the baseline with α= 90 ∘. The study can inspire the design of PCM storage geometries with efficient waste heat recovery in the industrial applications.