High-temperature heat pumps represent an emerging technology with a great potential in supplying clean heat to energy intensive industries. Suitable refrigerants for high-temperature heat pumps (up to 200 °C) have not been identified yet. This work aims to analyze the performance of binary mixtures as working fluid in high-temperature heat pumps delivering heat up to 200 °C with a special focus on zeotropic mixtures. Three relevant processes with different heat sources and sinks were selected to integrate the heat pump: latent/latent (e.g. distillation processes), latent/sensible (e.g. superheated steam drying), sensible/sensible (e.g. pressurized water production). To determine the best working fluid and cycle configuration for each process, an optimization framework was developed with the maximization of the coefficient of performance as objective function. For the first case with a latent heat sink and heat source, the best performing binary mixtures were near-azeotropic with slightly higher coefficient of performance compared to pure fluids. Moreover, binary mixtures provided several advantages such as the reduction of the compression ratio and compressor outlet temperature compared to pure fluids. A similar behavior was observed for the second case with a latent heat source and a sensible heat sink. For the third case with a sensible heat sink and heat source, binary mixtures resulted in a higher coefficient of performance (10 %) compared to pure fluids. Most of the best performing mixtures were hydrocarbons with high risk of flammability. Water/ammonia was the only mildly-flammable mixture among the top mixtures.

高温热泵是一种新兴技术，在为能源密集型行业提供清洁热能方面具有巨大潜力。尚未确定适用于高温热泵（最高 200 °C）的制冷剂。这项工作旨在分析二元混合物作为工作流体在高温热泵中的性能，可提供高达 200 °C 的热量，特别关注非共沸混合物。选择具有不同热源和汇的三个相关过程来集成热泵：潜/潜（例如蒸馏过程）、潜/显（例如过热蒸汽干燥）、显/显（例如加压水生产）。为每个过程确定最佳工作流体和循环配置，开发了一个以性能系数最大化为目标函数的优化框架。对于具有潜热沉和热源的第一种情况，与纯流体相比，性能最佳的二元混合物接近共沸，性能系数略高。此外，二元混合物提供了几个优点，例如与纯流体相比压缩比和压缩机出口温度降低。对于具有潜热源和显热沉的第二种情况，观察到类似的行为。对于具有显热沉和热源的第三种情况，与纯流体相比，二元混合物产生更高的性能系数 (10%)。大多数性能最好的混合物是具有高易燃性风险的碳氢化合物。