Abstract This study presents a novel dual-temperature air-source heat pump system with an ejector using zeotropic mixture R1270/R600a. The system provides a high-temperature heat source (around 60 °C hot water) and low-temperature heat source (around 35 °C hot water) respectively. The system improves its performance via the application of an ejector. The mathematical model based on the energetic method is established to analyze and compare the performance between the novel dual-temperature air-source heat pump system (DTHP-II and DTHP-III) and the conventional dual-temperature air-source heat pump system (DTHP-I), including the heating coefficient of performance (COPh), the heating capacity per volumes (qv) and the second law efficiency (ηII). The results show that the DTHP-II and DTHP-III systems significantly outperform the DTHP-I system under various operation conditions due to the application of ejector. Compared with the DTHP-I, the COPh, qv and η = 2 \ * ROMAN II of DTHP-II are improved by 20.2%, 19.5% and 18.2%. Again, compared with the DTHP-II, the COPh, qv and ηII of DTHP-III are improved by 36.5%, 37.2% and 38.5% respectively. The heat source temperature affects heat pump system performance significantly. And the DTHP-II and DTHP-III save more energy under the demand for a higher temperature source. Mass fraction of R600a in the zeotropic mixture (z) and the high low-temperature heat source load ratio (LR) show a noticeable effect on the system performance, which should be given attention when designing the DTHP system.

中文翻译：

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R1270/R600a共沸混合物双温空气源热泵复合喷射器的热力学分析

摘要 本研究提出了一种新型双温空气源热泵系统，该系统带有使用共沸混合物 R1270/R600a 的喷射器。系统分别提供高温热源（约60°C热水）和低温热源（约35°C热水）。该系统通过喷射器的应用提高了其性能。建立基于能量法的数学模型，对新型双温空气源热泵系统（DTHP-II和DTHP-III）与传统双温空气源热泵系统（DTHP-II和DTHP-III）的性能进行分析比较（ DTHP-I)，包括加热性能系数 (COPh)、单位体积加热容量 (qv) 和第二定律效率 (ηII)。结果表明，由于喷射器的应用，DTHP-II和DTHP-III系统在各种运行条件下均显着优于DTHP-I系统。与DTHP-I相比，DTHP-II的COPh、qv和η = 2 \ * ROMAN II分别提高了20.2%、19.5%和18.2%。同样，与DTHP-II相比，DTHP-III的COPh、qv和ηII分别提高了36.5%、37.2%和38.5%。热源温度显着影响热泵系统性能。并且DTHP-II和DTHP-III在对更高温度源的需求下更节能。共沸混合物中 R600a 的质量分数 (z) 和高低温热源负载比 (LR) 对系统性能有显着影响，设计 DTHP 系统时应予以注意。