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Organic Rankine Cycles (ORC) transform low-temperature heat into electrical power. To exploit the full potential of a low-temperature heat source, the ORC system is tailored to the specific application. Tailoring an ORC system is challenging, since both process and working fluid have to be optimized simultaneously. We present an approach for integrated design of ORC process and working fluid that enables tailoring an ORC process and the working fluid in a single optimization problem. This approach builds upon the continuous-molecular targeting-computer-aided molecular design (CoMT-CAMD) approach presented

Thermo-economically optimal design = optimal molecule + optimal process + optimal equipment.

Knowledge of mixtures' phase equilibria is crucial in nature and technical chemistry. Phase equilibria calculations of mixtures require activity coefficients. However, experimental data on activity coefficients is often limited due...

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Zeotropic mixtures are widely discussed as alternative refrigerants for vapor‐compression cooling appliances and heat pumps. Mixtures can increase efficiency due to their nonisothermal phase change. In theoretical studies, zeotropic mixtures show significant benefits for efficiency if the temperature glide of the mixture matches the temperature change in the heat transfer fluids. Such large benefits have never been observed in experiments. First, this article clarifies the gap between simulations and experiments. Second, it is shown how zeotropic mixtures could increase efficiency in real plants. The analysis is based on experimental results from a heat pump with three zeotropic mixtures and on theoretical studies that also include a physical compressor model. The compressor performance is shown to depend strongly on composition. Therefore, the compressor efficiency is the key parameter for large benefits of zeotropic mixtures beyond well‐matching temperature glides. Based on these findings, a fluid database is screened for fluids with well‐matching temperature glides and high compressor efficiencies, utilizing a physical compressor model. As a result of the screening, the zeotropic mixture R152a/R32 is identified. The corresponding simulations show that zeotropic mixtures can achieve large benefits in heat pump efficiency if the pure components have similar and high compressor efficiencies.