Carbonized loofah sponge fragments enhanced phase change thermal energy storage: Preparation and thermophysical property analysis

A mixture of polyethylene glycol and stearic acid is developed to extend the working temperature range and improve the heat utilization efficiency, and composited with carbonized loofah sponge fragments using melt impregnation method to improve the thermal conductivity of solid-liquid phase change material and find a solution for its leakage issue. The combination of different components, thermal stability, phase change behavior, thermal conductivity, shape stability, temperature response time and application cost are investigated. The results reveal that the mixture has two phase change temperature peaks including 59.81 degrees C and 68.01 degrees C, latent heat of melting is 215.20 J & sdot;g 1 and latent heat of crystallization is 193.40 J & sdot;g 1. The composites of polyethylene glycol, stearic acid and carbonized loofah sponge fragments is in a physical. Compared to the mixture, the latent heat of the composites gradually decreases, with a maximum decrease of latent heat of melting approximately 12.69 %, a maximum decrease of latent heat of crystallization approximately 10.24 %. For the same content of additives, the latent heat of the proposed composites in this work is greater than that of polyethylene glycolbased and stearic acid -based composites. The thermal conductivity of the composites gradually increases, in a range from 4.47 % to 10.91 %. The thermal conductivity of polyethylene glycol -based and stearic acid -based composites is lower than that of the proposed composites in this work in the case of the same content of additives. The cost of the composites with 2.5 wt% carbonized loofah sponge fragments is with a maximum 33.59 times cheaper than that of the composites with graphene nanoplatelets. Thus, from the perspective of cost, the combination of mixture and carbonized loofah sponge fragments has good economic benefit for thermal energy storage. The proposed composites demonstrate good shape stability, temperature response behavior and good economic benefit, indicating their good application prospects for thermal energy storage.