Genetic techno-economical optimisation of alternative industrial heat pump cycles using hydrocarbons refrigerants

Industrial process heat offers substantial potential for electrification through high temperature heat pumps, particularly for steam generation. Natural refrigerants such as hydrocarbons are increasingly relevant due to regulatory pressure on synthetic fluids and their favourable thermophysical behaviour. When applied in two-stage flash cycle architectures, they can overcome temperature-lift limitations and improve economic performance yielding to a viable reduction of the levelized cost of heat for high-lift heat pump applications. In this study a combined thermodynamic and techno-economic assessment of two heat pump configurations operating exclusively with hydrocarbon refrigerants is presented. A systematic optimisation framework is developed and links physics-based property models with a component-resolved cost function and applies genetic optimisation to identify optimal states, refrigerant selection and cycle layouts across twenty industrially relevant operation points under varying exogenous factors e.g.: electricity prices, equivalent full load hours and plant sizes. Existing studies have not provided an integrated optimisation-based performance comparison of two-stage cycles for sole use of alkanes as refrigerants for steam generation across such a broad range of boundary conditions. The results show that alternative configurations tailored to hydrocarbon properties can reduce the levelized cost of heat by 12.6% on average, with maximum reductions of up to 17% compared with a standard industrial heat pump layout. Direct evaporation is consistently more economical than flash-tank steam generation. Overall, the findings demonstrate that appropriately configured hydrocarbon-based heat pumps can significantly improve the economic viability of industrial steam supply.