Performance comparison of an air/water heat pump using a minichannel coil as evaporator in replacement of a fin-and-tube heat exchanger

•The performance of an air/water heat pump is experimentally measured.•Two different evaporators, minichannel and fin-and-tube coil are compared.•Experimental results are used to validate a model developed using a design software.•In all cases the refrigerant charge and the efficiency are lower using a minichannel coil.•The advantage of replacing a fin-and-tube evaporator by a minichannel evaporator is not clear. This paper reports the results of an experimental and numerical study of the use of a minichannel coil and a fin-and-tube coil in an air/water heat pump working as evaporator when the system is working in heating mode. The experimental installation developed to test the heat pump unit is briefly described and then the experimental results are presented. Alternatively, the heat pump is modelled using a refrigeration system design program. The results obtained using this model are compared to experimental results allowing the validation of the model. Once the model is validated, it is used to numerically determine the distribution of refrigeration charge and other interesting parameters not experimentally measured. Finally, an analysis of the numerically obtained results is presented in order to study the influence of several operating conditions on refrigerant charge, system COP and heating power for both types of evaporators tested.