A numerical framework for optimizing working fluid selection and cycle configurations in high-temperature heat pumps for industrial applications: Methodology and a case study

Renewables, electrification and waste heat recovery are crucial strategies for achieving carbon neutrality in the field of industrial heat supply. Process heating electrification, particularly through high-temperature heat pumps (HTHPs), is a cornerstone for achieving this goal. With the capability to reach temperatures of up to 200 °C, HTHP is considered a promising solution across several industries. Optimizing HTHP requires an assessment strategy that balances thermodynamic performance, environmental impact and economic feasibility. In this paper, a framework for the technical, economic and environmental assessment is presented and a numerical model is developed to design and simulate seven alternative HTHP cycle configurations with a pre-selected list of working fluids to be compared (chosen according to environmental criteria and thermophysical properties values). For each fluid-configuration pair, equipment sizing, energy and mass balances and economic-environmental indicators are evaluated. Model consistency and validation are performed through two approaches: benchmarking against experimental datasets and model results from relevant literature references. The model is then applied to an industrial case, a brewery process, for which pinch analysis has been carried out. Two integration scenarios are evaluated: (i) a single HTHP is employed to fulfill the entire hot utility as steam at T > 105 °C and (ii) two HTHPs are utilized, with one delivering a portion of the hot utility as hot water at T < 55 °C, and the second providing the remaining demand as steam at T > 105 °C.