Capture of cold energy from liquid nitrogen using a brazed plate heat exchanger

Energy use optimization is one of the numerous way to reduce the impact of the CO₂ on the environment. The work presented in this paper explores the possibility to apply the Brazed Plate Heat Exchanger (BPHE) technology to enhance the heat transfer between an extremely cold liquid gas such as nitrogen or air and low-grade heat media such as hot water. BPHEs are known to be characterised by high turbulent flows and high heat transfer rate and thus are the best candidate to guarantee quick heat transfer between the two fluids. Particular concern in this application is given by the risk of freezing water inside the BPHE. Considering the high complexity in the internal structure of the BPHE, the work is based on its analysis using x-ray tomography and CFD via a commercial software. CFD analysis was carried out using a first simple geometry and physics to verify the feasibility of the study. Given the promising results (quick heat transfer and tempered water temperature), subsequent study will be focused on more complex geometry and realistic physics to acquire a comprehensive and exhaustive view of the problem.