热虹吸型散热器的热量输运机制及其与空气源热泵耦合特性研究

Air source heat pump is a clean and energy efficient space heating equipment. However, its current utilization approach cannot take into account heating thermal comfort while fully utilizing its energy saving potential. Therefore, a thermosiphon-based radiator is proposed in this study to be used as the indoor terminal of air source heat pump. The idea fully utilizes the advantages of thermosiphon cycle, such as high heat transfer efficiency and rapid thermal response, and realizes the complementary advantage of air and hydraulic heating approaches. The study will be carried out focusing on the radiator and its hybrid system with air source heat pump. First, according to the characteristics of the radiator, the boiling heat transfer in the thermosiphon evaporation area caused by inner heat input will be investigated through visualization experiments and numerical simulation. On this basis, relevant heat transfer correlation will also be summarized. By breaking through the modelling difficulties of double-working-fluid and double-phase-transformation phenomenon, the heat transfer model of the radiator will be established to clarify its heat transportation mechanism under complex boundary conditions, which helps to obtain the optimal geometry of the radiator. Second, the coupling operation characteristics of the radiator and the heat pump will be investigated; the system energy efficiency and the balance of irreversibility will also be evaluated. Third, the thermodynamic model of the system will be developed; the basic criterion of system optimization will be established by discussing the influence of different parameters; the control approach of the system will also be established by inverse problem modelling from the standpoint of energy flow, with an aim to achieve an optimal balance between different mass and energy flows as well as the thermosiphon cycle and heat pump cycle. The research results can enrich the theory of thermosiphon, extend the theoretical meaning of heat pump heating, and provide support for promoting the sustainable development of heat pump system.

空气源热泵是一种清洁、高效的供暖设备。但当前基于热风或热水的利用方式却不能很好地兼顾采暖的舒适性和节能性。为此，提出了将一种热虹吸型散热器作为热泵采暖末端的设想。该设想充分利用了热虹吸循环传热效率高、热响应迅速等优点，实现了热风与热水采暖的优势互补。本研究拟围绕该散热器及其与空气源热泵构成的复合供热系统展开。首先，针对该散热器的特点，通过可视化实验和数值模拟探索热虹吸蒸发区在内热源作用下的沸腾换热规律。在此基础上，总结内热源存在时蒸发区工质的换热关联式。进而突破“双工质、双相变”换热体系分析难点，建立散热器传热模型，阐明其在复杂边界条件下的热量输运机制，并由此得到散热器设计的最佳结构方案。其次，通过实验探究散热器与热泵的耦合运行特性，进而获取系统能源利用效率和各部件不可逆度平衡原则。再次，构建系统热力学模型，通过探讨不同参数对其性能的影响，确立系统优化的基本准则，并以能量流为视角，采用反问题求解的手段，建立实现系统中各质量流与能量流以及热泵循环与热虹吸循环之间最优匹配的调控措施。相关研究成果有望进一步完善热虹吸理论，并拓展热泵采暖的理论内涵，对推进热泵系统的可持续发展具有理论指导意义。

在建筑领域“碳达峰、碳中和”的背景下，空气源热泵作为一种低能耗、低排放的供暖设备得到了广泛关注。然而，当前热泵应用却面临着采暖舒适性不足、运行稳定性欠佳等技术难题。为此，本项目提出了将热虹吸技术和热泵技术有机结合的设想。该设想利用了热虹吸循环传热效率高、热响应迅速等优点，通过运用一种新型热虹吸型散热器作为空气源热泵的采暖末端，实现了采暖舒适性、节能性与系统运行稳定性的统筹兼顾。本项目围绕该散热器及其与空气源热泵构成的复合供热系统开展研究。首先，针对该散热器的特点，通过可视化实验探索了热虹吸蒸发区在内热源作用下的沸腾换热规律，进而突破了双工质、双相变换热体系分析难点，建立了散热器传热模型，阐明了其在复杂边界条件下的热量输运机制。其次，通过实验探究了散热器与热泵的耦合运行特性，进而获取了系统性能和各部件不可逆度平衡原则。再次，构建了系统动态仿真模型，通过探讨不同参数对其性能的影响，确立了系统优化的基本准则，并以能量流为视角，采用反问题求解的手段，建立了系统变工况运行控制方法。通过上述研究，本项目发现热虹吸工质在内热源作用下的沸腾换热规律基本符合经典核沸腾理论。然而，采用常见的换热关联式预测其沸腾换热系数却会带来较大误差。同时，针对双工质、双相变换热体系，可采用分布参数法与集总参数法相结合的手段对其进行热力学描述。这样可同时保证数学模型的稳健性和求解结果的准确性。另外，复合供热系统的性能受多个参数共同影响。在系统各部件中，压缩机的㶲损失、㶲损率最大，同时其转速可作为运行控制的主要手段。本项目研究阐明了热虹吸型散热器的热量输运机制；揭示了新型散热器与空气源热泵的耦合运行规律；确立了复合供热系统优化与控制的基本准则。研究成果可提升热泵技术的发展水平，并为建筑领域的绿色低碳发展提供坚实的理论基础和可行的技术路径。