Thermodynamic Mapping of a R744 Simple Cycle for HTHPs: Application to a Brewery Process

High Temperature Heat Pumps (HTHPs) are a key technology toward industry decarbonization. Based on the variety of needs and boundaries, significant research efforts are underway to identify the best technical solutions and the most suitable refrigerants. Among natural refrigerants, which offer long-term sustainable options, carbon dioxide (CO2) offers additional safety benefits. This paper conducts a thermodynamic analysis of a simple CO2 cycle, exploring its application limits as HTHP working fluid. It presents a map of the maximum Coefficient of Performance (COP), along with its corresponding operating points, as functions of source and sink inlet temperatures and sink temperature lift. The methodology incorporates pinch point analysis for the gas cooling process, enabling precise optimization of CO2 thermodynamic cycles under varying conditions. The findings serve as preliminary design recommendations to discuss HTHP applicability. The outcomes of this study are applied to the heating processes of a small craft brewery, to quantify the impact of an HTHP as a substitution for gas burners and limiting electric heaters’ contributions, while keeping simplicity in the system layout and complying with safety requirements for indoor installations.