**6. Conclusions**

This chapter is presented the boiling process of refrigerant in horizontal microfin tube. Those are related to the understanding of flow patterns and the procedure to build some flow pattern maps. Some of new correlations to calculate heat transfer coefficient and pressure drop of refrigerant during boiling process have been presented. Detailed step by step to calculate heat transfer performance for typical example is also introduced. However, this is still not enough for this topic, with the new structure of microfin tubes, new refrigerants, this just only the general method to estimate the value, it should be confirmed by experimental method and create the new correlation to extend the wide range of application working conditions.

#### **Acknowledgements**

We would like to thank Ho Chi Minh City University of Technology (HCMUT), VNU-HCM for the support of time and facilities for this study.
