Modeling and Experimental Validation of a Multifluid Brazed Plate Heat Exchanger for Multi-Circuit Heat Pump Applications
Multi-fluid plate heat exchangers (PHE) enable compact, multifunctional heat management for thermal systems that must dynamically integrate with multiple heat sinks or sources, decarbonized examples of which are solar, air, water and ground-source heat reservoirs, among others. This paper presents a modeling and validation framework for a multifluid brazed PHE designed for a multi-circuit heat pump (HP) system coupled to a shared water loop. A steady-state finite-volume thermal-hydraulic model is developed using Python and a transient dynamic model is implemented in Modelica using the Dymola simulation environment to capture variable-temperature, multi-source and multi-sink operation. The models are validated against experimental data from a dual-circuit HP using R32 as the refrigerant, for water cooling applications. This modelling framework can be extended to natural refrigerants and next-generation low-global warming potential (GWP) refrigerant mixtures, providing a robust foundation for future design, optimization, and control of advanced thermal systems integrating alternative energy sources, waste heat recovery and thermal energy storage.