Development of CH3COONa·3H2O-Glycine-KCl composite phase change material for the swimming pool heating system

Abstract

With the improvement of modern living standards, the number of indoor and outdoor swimming pools has increased. However, the high energy consumption and heating costs in winter do not align with the requirements of green development. Therefore, in this study, a novel Composite Phase Change Material (CPCM) was developed to be integrated with a solar-air source heat pump swimming pool heating system. This system aims to provide longer heating durations and reduce temperature fluctuations, while also alleviating the pressure on national energy supply during peak energy consumption. Glycine (Gly) and potassium chloride (KCl) were combined with sodium acetate trihydrate (SAT) to prepare a shape-stabilized CPCM (SAT- Gly- KCl CPCM). It was integrated into a swimming pool heating system to justify the impact of the new material. Experimental results have demonstrated some major properties of this material, the melting point, latent heat value and supercooling degree were 40.3 °C, 274.4 J/g and 1.36 °C for the laboratory preparation, and 40.9 °C, 249.5 J/g and 1.42 °C for the large-scale preparation, respectively. The material also exhibited good stability and thermal reliability. When SAT-Gly-KCl CPCM was applied to a swimming pool heating system, it was found that 100 and 200 phase change thermal storage modules increased heating durations by 9.89 and 10.59 times, respectively, compared to the control group. Therefore, the SAT-Gly-KCl CPCM presents a promising solution for swimming pool heating systems. This study contributes to the further development and application of CPCMs in such systems, offering improved energy efficiency and stability.