Modelling of Thermal and Energy Systems Research Group

Study of evaporators and condensers based on minichannel technology for its application in refrigeration equipment, aire conditiioning and heat pump working in steady state (2012-2014)

This is a project funded by the Spanish Ministry of Economy and Competitiveness. It is partially financed by the European FEDER.

This project is oriented to the study and increase our knowledge about the performance of new technology of compact heat exchangers based on minichannels tubes.

The main objective of the project is to have the knowledge about the performance of minichannels heat exchangers working as evaporators and condensers and secondly, to study its integration in refrigeration, air conditioning and heat pump equipment with the objective of minimising refrigerant charge, and to maximising energy efficiency.

Based on previous knowledge and using validated techniques for the study of other heat exchangers type, the project is focused at the beginning on the study of fundamental performance differences between fin and tubes heat exchangers and minichannels heat exchangers. Also, experiments about performance of new refrigerantes able to retrofit the actual high GWP ones. Most of the candidates to retrofit the actual HFCs are Hydrocarbons (HCs) and HydroFluoroOlefins(HFO), fluids that are flammable and one important design constraint is the system charge.

Minichannels technology in evaporators and condensers is the most adequate for minimising refrigerant charge at same capacity and even enhancing efficiency of the refrigeration equipment. The project is mainly based on experimental methodology in order to study of different refrigerants working with different arrangements, geometries and sizes of minichannels compact heat exchangers.

The project is divided into two subproject which are the result of the collaboration of two Universities.

• Subproject 1, to develop at Universidad Politécnica de Valencia, has the objective of developing calculation models of minichannels heat exchangers, validation of heat transfer and pressure drop correlations in the air and refrigerant side and to study its integration in equipment focusing the study in particular problems of the minichannels HX like evaporator water drainage, refrigerant maldistribution, longitudinal conduction effects and use of refrigerant alternatives to the actual HFCs.

• Subproject 2, to develop at Universidad Politécnica de Cartagena, has the objective of studing boiling and condensation heat transfer and pressure drop inside minichannels with new refrigerants. To fulfill this, experimental correlations will be developed and compared to the results obtained with others obtained for traditional refrigerants used by other researchers.