The comparison of evaporator types and anti-freezing performance of low temperature chiller is an important issue involving the design and performance optimization of refrigeration systems.

1. Comparison of types and performance of evaporators

The processing efficiency of different types of tube evaporators (such as single-tube double-finned tube evaporators, double-finned tube evaporators with cold storage, and single-tube eight-finned tube evaporators) varies at different evaporation temperatures. For instance, the processing efficiency of the single-tube double-finned tube evaporator at evaporation temperatures ranging from -14°C to -6°C is 0.92 to 0.96 respectively, while the processing efficiency of the double-finned tube evaporator with cold storage and the single-tube eight-finned tube evaporator is relatively lower, ranging from 0.88 to 0.92 respectively. This indicates that the performance of evaporators with different structures varies in low-temperature environments, and optimizing the fin structure and adding cold storage materials can enhance heat transfer efficiency.

2. Classification and Characteristics of evaporators

According to and, the types of evaporators include dry type (non-flooded type), recirculation type, flooded type and spray type, etc. Dry evaporators are suitable for cold storage or cold storage air conditioning. They have the advantages of less liquid filling and less cold loss, but their heat transfer coefficient is relatively low. The fin spacing of low-temperature evaporators is usually larger (6-10mm) to enhance heat transfer efficiency, but they are prone to frosting and require regular maintenance. In addition, the evaporation pressure of the low-temperature evaporator is relatively low, and the requirement for the oil return capacity of the refrigerant is high. Anti-freezing protection should be noted.

3. Anti-freezing performance and anti-freezing protection

Low-temperature evaporators are prone to frosting or freezing in low-temperature environments, which affects the refrigeration effect. According to the information, the evaporator of the screw-type low temperature chiller group is usually equipped with anti-freezing protection function to prevent equipment damage in low-temperature environments. In addition, it is mentioned that the fin spacing of the low-temperature evaporator is relatively large to reduce the risk of frosting, but it needs to be cleaned regularly to maintain the heat transfer efficiency.

4. The influence of refrigerant and evaporation temperature

According to different refrigerants (such as R407F, R404A, R407A), their performance (such as evaporation efficiency, refrigeration capacity, and energy efficiency ratio) varies at different evaporation temperatures. For instance, the evaporation efficiency and refrigeration capacity of R407F at low temperatures are lower than those of R404A, but its efficiency is slightly higher. In addition, a decrease in evaporation temperature usually increases the refrigeration capacity, but it may also raise the compression ratio and energy consumption.

5. Comprehensive Analysis of evaporator types and anti-freezing Performance

The anti-freezing performance of a low-temperature evaporator mainly depends on its structural design (such as fin spacing and anti-freezing protection), refrigerant selection, evaporation temperature control, and maintenance. Optimizing the evaporator structure (such as adding cold storage materials and optimizing the fin design) and selecting appropriate refrigerants (such as low-GWP refrigerants) can enhance the anti-freezing performance and overall energy efficiency.

Conclusion

The type of evaporator of low temperature chiller is closely related to its anti-freezing performance. The performance of different types of evaporators varies in low-temperature environments. It is necessary to select the appropriate type of evaporator and refrigerant based on specific application scenarios, and enhance maintenance to ensure anti-freezing performance and long-term stable operation.