Generally, with the help of adding solid materials, the thermophysical behaviors of refrigerant can be modified. In this work, four kinds of organic refrigerants (i.e. ethane R170, 1-fluoroethane R161, 1,1-difluoroethane R152a, and 1,1,1-trifluoroethane R143a) mixed with metal–organic framework UIO-67 nanoparticles are selected as the objects, their thermodynamic energy, adsorption, desorption heat, and energy storage properties are investigated by means of molecular simulations and thermodynamic calculations. The simulation method and calculation details are elaborated. The results illustrate that the relationship between the change of thermodynamic energy and the temperature is linear, and the adsorption of refrigerants in UIO-67 can be reinforced owing to the fluorine atom in the refrigerants. However, R170, the fluorine-free refrigerant, has greater enthalpy variation of desorption than the other three refrigerants containing fluorine atom under some pressures. The thermal energy storage capacity of the refrigerant/UIO-67 mixture is greater than that of the pure refrigerant at low pressure. Meantime, as the refrigerant undergoes phase transition, the weakened improvement of the energy storage property of the refrigerant/UIO-67 mixture is found in some cases. This work can not only enrich the content of researches about metal–organic heat carrier nanofluids (MOHCs), but also provide guidance for the performance improvement and practical application of organic refrigerants.

中文翻译：

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与 UIO-67 纳米粒子混合的制冷剂（R170、R161、R152a 和 R143a）的吸附和热能存储分析的分子模拟研究

通常，在添加固体材料的帮助下，可以改变制冷剂的热物理行为。在这项工作中，选择了四种有机制冷剂（即乙烷 R170、1-氟乙烷 R161、1,1-二氟乙烷 R152a 和 1,1,1-三氟乙烷 R143a）与金属-有机骨架 UIO-67 纳米粒子混合作为制冷剂。通过分子模拟和热力学计算研究了物体的热力学能、吸附、解吸热和储能特性。详细阐述了模拟方法和计算细节。结果表明，热力学能的变化与温度呈线性关系，并且由于制冷剂中的氟原子，UIO-67对制冷剂的吸附作用得到了加强。然而，R170，无氟制冷剂，在一定压力下，其解吸焓变比其他三种含氟制冷剂大。制冷剂/UIO-67混合物的蓄热能力大于低压纯制冷剂的蓄热能力。同时，随着制冷剂发生相变，在某些情况下，制冷剂/UIO-67混合物的储能性能改善减弱。该工作不仅可以丰富金属-有机热载体纳米流体（MOHCs）的研究内容，还可以为有机制冷剂的性能提升和实际应用提供指导。制冷剂/UIO-67混合物的蓄热能力大于低压纯制冷剂的蓄热能力。同时，随着制冷剂发生相变，在某些情况下，制冷剂/UIO-67混合物的储能性能改善减弱。该工作不仅可以丰富金属-有机热载体纳米流体（MOHCs）的研究内容，还可以为有机制冷剂的性能提升和实际应用提供指导。制冷剂/UIO-67混合物的蓄热能力大于低压纯制冷剂的蓄热能力。同时，随着制冷剂发生相变，在某些情况下，制冷剂/UIO-67混合物的储能性能改善减弱。该工作不仅可以丰富金属-有机热载体纳米流体（MOHCs）的研究内容，还可以为有机制冷剂的性能提升和实际应用提供指导。