Ceramic Air-to-Air Recuperator for energy recovery in HVAC systems: CFD analysis and comparison with experimental tests

This paper explores the application of a Ceramic Air-to-Air Recuperator (CAAR) as an energy recovery device within HVAC systems. Specifically, the CAAR is analysed through Computational Fluid Dynamics (CFD) techniques. Ansys Fluent has been used as the software for the simulations. The system geometry is meticulously replicated and meshed to generate a three-dimensional model closely mirroring reality. Subsequently, simulations are conducted in both heating and cooling modes. The outcomes of the CFD analysis are compared with data obtained from a dedicated experimental test rig. The observed Prediction Relative Error (PRE), representing the relative error on the device outlet temperatures, is consistently below 15 % for primary air and 10 % for secondary air accross all simulations. These findings substantiate the assertion that the CFD model is robust and offers an effective tool for accurately designing and simulating the CAAR device performance under different operative conditions. In this way, it is possible to open up an important perspective on the widespread utilisation of the CAAR device in HVAC systems, promoting the energy efficiency and decarbonisation of this sector.