# Study on the Dynamic Generation of Subcooled Water Using a Compact Heat exchanger
## 4 Conclusions  
This paper discussed experiments involving a compact heat exchanger with a high heat transfer performance, small hydraulic diameter, and extremely short heat transfer channels to build a dynamic generation setup for subcooled water. The generation conditions and control methods for high subcooling degrees and long durations were explored using tap water and non-freezing liquid as working fluids. The conclusions are as follows:  
1. The dynamic generation of subcooled water with a high subcooling degree from tap water is feasible. The generation of ice or ice slurry through this processes shows the system's potential for applications in food engineering, indoor snowmaking, ice storage, and other fields. The experiments also proved that the compact heat exchanger is suitable for the dynamic generation of subcooled water. The concept of using the high-efficiency heat transfer performance of the compact heat exchanger for instantaneous heat transfer and shortening the channel length and small hydraulic diameter is also correct. Through the experiments, we achieved the generation of subcooled water at a minimum of \(-3.8\)\({}^{\circ}\)C, and the \(-2.8\)\({}^{\circ}\)C average-temperature subcooled water generation lasted for 108 min.  
2. The deployment of compact heat exchangers can achieve higher inlet water temperatures, greater subcooling degrees, and longer dynamic generation durations than the use of other types of heat exchangers. With the increase in the subcooling degree, the range of specific flux \(i\) suitable for the dynamic generation of subcooled water is narrowed, and a specific flux \(i\) of around 1.5 is more appropriate. The increase in the subcooling degree is more effective in releasing the subcooled water to form ice or ice slurry. The dynamic generation durations of the subcooled water determine the amount of ice produced. 3. Ice blockage also occurs when generating subcooled water with tap water using a compact heat exchanger. The reasons for ice blockage are as follows: (1) the impure particles in the tap water are more likely to promote the formation of ice nuclei at high subcooling degrees; (2) the micro-icing on the surface of the compact heat exchanger may provide ice nuclei for the subcooled water at the outlet; and (3) the two turns at the outlet of the compact heat exchanger may also cause minor energy disturbance affecting the subcooled water flowing out of the heat exchanger for release through subcooling, especially at high subcooling degrees at which ice blockage is more likely to occur. 4. The analysis of the results clarified that compact heat exchangers for the dynamic generation of subcooled water require further design guidelines to shorten the channels, reduce the hydraulic diameter, optimize the shape of the channels, and increase the number of channels. In addition, the heat exchanger's surface structure prevents icing and achieves greater subcooling degrees, laying a foundation for later explorations of the dynamic generation of deep subcooled water.  
Software, S.S.; Investigation, K.W.; Writing--review & editing, P.C. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors are grateful to [PERSON] of Zhejiang Xuebolan Technology Co., Ltd., for his financial and technical support, and [PERSON] for her help in this research.  
The authors declare no conflict of interest.