Quantification of two-phase refrigerant distribution in brazed plate heat exchangers using infrared thermography

This paper presents a method to quantify two-phase refrigerant flow distribution in brazed plate heat exchangers (BPHEs) from infrared images. In this method, the two-phase length of the refrigerant channels is first estimated from the IR images of the BPHE sidewall. Then, the refrigerant distribution is adjusted in a BPHE evaporator model, to have the predicted two-phase length of the channels match the identified results from the IR images. The overall performance of the BPHE is also predicted in the quantification process. The proposed quantification method is validated by the experimental data: heat exchanger capacities, pressure profiles, and surface temperature profiles of the sidewall. This non-intrusive method can effectively quantify two-phase refrigerant distribution in BPHEs with the premise that all liquid refrigerant has evaporated in the heat exchangers.