Development of innovative and high-efficiency air conditioning system using chemical humidity conditioning

当今空调系统最大的问题就是除湿。常规空调需要降温至露点，当目标温度仅为19℃时，需要降温至5℃，导致系统效率较低。为了解决这一问题，我们提出了一种高效的化学湿度调节系统，该系统采用悬浮在惰性溶剂中的十水碳酸钠，并确定了基本的除湿特性。首先，将十水碳酸钠悬浮在正戊醇中制备浆料，并对其进行基本反应检查，测定反应速率。同时，对溶剂进行筛选，综合考虑价格、安全性、气味等特点，聚乙二醇适合我们的目的。对碳酸钠浆料在聚乙二醇中进行重复反应，发现完全脱水成一水合物反应活性降低，但脱水后部分十水合物保持反应活性，导致稳定的重复水化脱水。此外，用聚乙二醇测定了浆料的水化/脱水平衡水浓度。测定了聚乙二醇-水混合物的水蒸气压，确定了UNIQUAC方程的参数。测定了直接决定工艺性能的水化率，确定了水化率方程，从而计算出厨房除湿的理论最小体积。为此，搭建了悬浮式气泡塔反应器，进行了改变空气流速和固体浓度的除湿实验。结果表明，反应速率的决定步骤是水蒸气从气相到液相的传质过程。

The largest problem of today's air conditioning system is the dehumidification. Conventional air conditioning needs cooling down to dew point, and when target temperature is only 19℃, cooling down to 5℃ is needed, which results in low system efficiency. To circumvent this problem, we proposed a high-efficiency chemical humidity conditioning system where sodium carbonate decahydrate suspended in inert solvent is employed, and fundamental dehumidification characteristics were determined. First, we prepared slurry by suspending sodium carbonate decahydrate in n-pentanol, checked the fundamental reaction to proceed, and reaction rate was determined. In parallel, screening of the solvent was conducted, and considering price, safety, smell, and other characteristics, polyethylene glycol was found to be suitable for our purpose. Repetitive reaction was conducted for the sodium carbonate slurry in polyethylene glycol, and it was found that complete dehydration to monohydrate results in decrease in reactivity, but that dehydration leaving some decahydrate maintained reactivity, leading to stable repetition of hydration and dehydration. In addition, equilibrium water concentration for hydration/dehydration was determined for the slurry using polyethylene glycol. The water vapor pressure over polyethylene glycol-water mixture was measured, and parameters of UNIQUAC equation were determined. Hydration rate, that directly determines the process performance, was measured, and the rate equation was determined so that theoretical minimum volume for dehumidification of kitchen was calculated. For demonstration purpose, suspended bubble column reactor was built and dehumidification experiment was conducted with changing air flow rate and solid concentration. From the result, it was found that rate determining step was mass transfer of water vapor from gas phase to liquid phase.