热泵驱动的多级中空纤维膜液体除湿系统的能量匹配特性与热力学优化理论研究

Membrane-based liquid desiccant air dehumidification is highly desired in the field of HV&AC because it can overcome the problem of liquid droplet cross over existed in traditional direct-contact liquid desiccant air dehumidification systems. In this project, a heat pump driven multi-stage hollow fiber membrane based liquid desiccant air dehumidification system is proposed. It uses a hydrophobic-hydrophilic composite membrane to realize non-contacting air dehumidification. The problem of droplets cross over is prevented. It uses an air-cooled heat pump to realize salt solution heating/regeneration and cooling/absorption. Thus the solution corrosion of heat exchanger is avoided and the Coefficient of Performance (COP) is improved. It uses a multi-stage heating/regeneration and cooling/absorption process to reduce the irreversible loss of heat and mass transfer. In this project, the energy matching and thermodynamic optimization of the system will be investigated. The research content includes: to set up the thermodynamic model of the system, to realize the influence of operation parameters on system performance, to clarify the heat balance between components, to disclose the energy matching rule of the system. The investigation also includes: to set up the thermodynamic optimization theory of the system based on heat and mass entransy dissipation, to realize the optimal operating points between each stage, to clarify the multi-factor mechanism of optimizing the structural parameters and operating conditions, to disclose the new method of minimizing the thermodynamic irreversible loss of the system. All these efforts will build up the fundamentals of the system for future industrialization.

膜式液体除湿技术可克服传统气液直接接触方式造成的空气带液飞沫对空气污染的弊端，在室内空气控制领域有重大的需求。本项目提出一种热泵驱动的多级中空纤维膜液体除湿系统，采用新型的亲水/憎水中空纤维膜将吸湿溶液与空气分隔，避免空气带液污染。利用热泵对空气侧换热，实现吸湿溶液的冷却除湿与加热再生，避免换热器的溶液腐蚀，提高系统能源综合利用效率。将多级的冷却除湿与加热再生替代传统的单级过程，减少系统热质传递的不可逆损失。项目将对该系统的能量匹配特性和热力学优化进行研究。所涉及内容包括：建立系统的热力学模型，认清各操作参数对系统性能的影响，阐明各组件间的热量平衡关系，揭示系统的能量匹配规律。建立基于热量积与质量积耗散的系统热力学优化理论，确定多级系统每级间的最佳工况点，阐明结构参数和运行条件的多因素优化机理，揭示系统热力学不可逆损失减少的新途径。上述研究为未来系统的实用化研究打下理论的基础。

膜式液体除湿技术可以克服传统气液直接接触方式造成的空气带液飞沫对空气污染的弊端，在室内空气控制领域有重大的需求。本项目提出一种热泵驱动的多级中空纤维膜液体除湿系统，采用一种亲水/憎水的中空纤维膜将吸湿溶液与空气分隔，避免空气带液污染。利用热泵对空气侧换热，实现吸湿溶液的冷却除湿与加热再生，避免换热器的溶液腐蚀，提高系统能源综合利用效率。将多级的冷却除湿与加热再生替代传统的单级过程，减少系统热质传递的不可逆损失。项目首先对系统的能量匹配特性展开研究，建立了系统热质传递的热力学模型，研究了各操作参数对系统性能的影响，阐明各组件间的能量供需关系，揭示系统的能量匹配规律。其次建立了系统的动态热力学模型，研究了系统的非稳态热湿传递规律，阐明了系统的动态响应机理。还进一步对系统的热力学性能进行优化，建立了基于不可逆耗散最小的优化设计模型，揭示减少系统热力学不可逆损失的途径。建立了基于系统能耗最低的优化运行模型，确定多级系统每级间的最佳工况点，阐明操作条件的多因素优化机理。上述研究为未来系统的实用化研究打下理论的基础。