# Performance Study and Efficiency Improvement of Ice Slurry Production by Scraped-Surface Method
## 1 Introduction
Moreover, the effects of factors such as scraping speed and solution flow rate on the energy consumption during the scraping process have not been reported. Therefore, it is necessary to study the effects of these factors to increase the efficiency of ice slurry production. Improving the crystallization and accelerating the formation of ice crystals are important areas of research in recent years. In previous reports, researchers have pointed out that nanoparticles can reduce the supercooling degree of base fluid and enhance thermal conductivity significantly [21; 22; 23; 24; 25]. The supercooling degree is usually defined as (\(T\)-\(T_{\text{f}}\)) K, where \(T\) is the temperature of the theoretical freezing point and \(T_{\text{f}}\) is the temperature immediately before supercooling dissolution [26]. In this paper, we have followed this definition. [PERSON] et al. [27] investigated the nucleation of nanofluids and found that the supercooling degree was reduced by adding nanoparticles, such as \(\alpha\)-Al\({}_{2}\)O\({}_{3}\), \(\gamma\)-Al\({}_{2}\)O\({}_{3}\) and SiO\({}_{2}\), into pure water. [PERSON] et al. [28] studied the phase transition temperature and latent heat of CuO-oleic acid nanofluids, and concluded that CuO-oleic acid nanofluids can decrease the solidification time and can be recommended as better phase change materials (PCMs) for thermal energy storage applications. [PERSON] et al. [29] investigated the supercooling degree of Al\({}_{2}\)O\({}_{3}\)-H\({}_{2}\)O nanofluids and found that the supercooling degree of 0.2 wt\(\%\) nanofluids was reduced by 70.9\(\%\) and the starting time of freezing was advanced by 32.9\(\%\). [PERSON] et al. [30] investigated TiO\({}_{2}\)-BaCl\({}_{2}\)-H\({}_{2}\)O nanofluids and found that the supercooling degree was reduced by 84.92\(\%\) with volume fraction of 1.13\(\%\). [PERSON] et al. [31] investigated the solidification behavior of TiO\({}_{2}\) nanofluid and deionized water. The experimental results showed that the supercooling degree of TiO\({}_{2}\) nanofluids without surfactants was approximately 11.5\(\%\) lower than that of deionized water, and the values did not change significantly with nanoparticle concentration. [PERSON] et al. [32] reported that the supercooling degree of Cu/pure water nanofluids with 0.1 wt\(\%\) concentration was reduced by 20.5\(\%\). [PERSON] et al. [33; 34] researched the supercooling degree and nucleation behavior of graphene oxide nanofluids and reported that many nucleation sites were found on the surface of graphene oxide nanosheets, which could reduce the supercooling degree of deionized water dramatically. However, these experimental results are based on small sample sizes. At present, few investigations and applications for ice slurry production with nanofluids have been reported. It is not clear whether nanofluids can be applied to large-scale production of ice slurry. In this study, the effects of solution characteristics and system operating parameters on ice-making characteristics and energy consumption were studied. Simultaneously, nanosilica was used as an additive and its effect on enhancing ice crystal formation and improving system energy efficiency was investigated.