基于干燥剂除湿和蒸发制冷耦合的高效热泵循环研究

Developing high-efficient and energy-saving air conditioners is crucial for China to achieve the target on emission reduction. Based on the thermodynamic analysis of conventional compression air conditioning cycle, desiccant cooling cycle and hybrid desiccant heat pump cycle, a novel integrated desiccant heat pump cycle is proposed to obtain high efficient operation. In this novel cycle, desiccant coated evaporator/condenser is adopted to replace traditional evaporator/condenser, sensible and latent load are handled by desiccant coated evaporator under high evaporation temperature, and meanwhile released condensation heat from desiccant coated condenser is utilized as a stable heat source to regenerate desiccant material. It can be seen that less electrical consumption is required by this new cycle due to high evaporation temperature, also isothermal dehumidification thermodynamic process is realized. Moreover, urban heat island effect causing by condensation heat from conventional air conditioning system can be effectively reduced. In this project, theoretic analysis on thermodynamic principle, optimal combination of refrigerant and desiccant material, dynamic simulation as well as experimental analysis on the system will be conducted. Based on these work, optimal construction and thermodynamic features of this novel cycle will be determined. Eventually, an innovative thermodynamic cycle with high COP and significant energy saving effect is realized, which can provide a new prospective for air conditioner industry.

实现热泵空调循环节能运行是缓解我国能源压力、达到减排目标的重要途径。本项目以高效节能热泵空调循环的建立为出发点，通过对压缩式热泵空调循环、吸附/吸收除湿循环以及复合式除湿热泵循环在热湿负荷处理热力过程中基础问题的分析，提出采用除湿换热器（除湿蒸发/冷凝器）替代传统热泵循环中的蒸发/冷凝器，通过高蒸发温度下制冷剂蒸发制冷和干燥剂吸附除湿实现热湿负荷的耦合处理，并采用冷凝热为干燥剂再生提供稳定热源，从而构建新型的一体式除湿热泵热力循环。新型循环不仅可以在高蒸发温度下运行，达到显著节能，而且实现了等温除湿并利用冷凝废热再生，由此建立的空调系统可以显著减小对城市热岛效应的影响。项目拟通过对新型循环热力学机理分析、制冷剂与干燥剂匹配研究、系统热动力学仿真及实验分析，完成循环的优化构建和热动力学特性研究，实现热泵空调循环COP显著提升和高效节能，通过创新热力循环模式的研究为空调产业发展提供新的方向。

实现热泵空调循环节能运行是缓解我国能源压力、达到减排目标的重要途径。基于此出发点，本项目围绕以除湿（蒸发/冷凝器）换热器替代传统热泵循环蒸发/冷凝器的新型一体化除湿热泵循环展开。在研究过程中，首先明确了一体化除湿热泵循环的优化构建方法，发展了新循环的分析评价方法与理论，揭示了其节能潜力与应用前景。在此基础上，针对循环区别于常规压缩式循环的蒸发/冷凝温度区间，对制冷剂进行了优选。同时，基于干燥剂降温除湿热力过程的传热传质模型建立干燥剂优选准则，明确复合干燥剂的优选方案及制备方法。进一步，对除湿换热器的耦合传热传质性能进行了理论与实验研究，提出了其传热传质弱关联耦合特性。通过构建完整的除湿热泵动态模型，理论上验证系统可行性并揭示了其热力学特性与能耗特点。最后，搭建了除湿热泵实验台，并在夏冬季工况下进行性能测试，探讨系统控制策略并据此优化系统设计，提高了系统能效与适应性。通过上述工作的开展，在理论方面：构建具有温湿度弱关联特性的新型除湿热泵循环，同时提出了新型循环制冷剂与干燥剂的优选原则，即理想的吸附剂在吸附-解吸平衡时有较大的单位质量含水率差和较大的涂敷密度，另外，揭示了循环传热传质弱耦合特性。在技术方面：确定了新型循环在15-20oC蒸发温区、40-50oC冷凝温区下制冷剂（R32和R410A）的选取，发现了吸湿盐修饰多孔物理吸附剂提升循环潜热负荷处理能力，优化了LiCl-介孔硅胶复合吸附剂的制备方法和涂敷工艺。建立了可准确预测除湿蒸发/冷凝器的双热源耦合传热传质数学模型及系统动态热力学模型。搭建了一体式除湿热泵循环的实验测试系统，在上海夏季工况下系统COP达到6.0以上，较传统空调热泵提升近一倍。项目成果发表SCI论文34篇，EI论文9篇，出版英文编著2本，申请我国发明专利15项，申报PCT国际专利2项。作为一种高效的空调热泵，形成了广泛国际影响，做国际大会报告5次。新型循环开拓了热泵空调领域研究的新思路，为空调产业发展提供了新方向。