吸湿剂固液汽三相储能/制冷/制热的循环机理研究

空调耗电量不断攀升，在空调季节常会发生用电短缺问题，利用工业余热或太阳能进行储能/制冷/制热，是缓解该问题的有效方法。然而，传统储能密度相对较低、热驱动制冷系统综合效率较低，制约了该技术推广应用。本项目以吸湿剂氯化锂/膨胀石墨-水为研究对象，研究三相（水合物结晶固体、吸湿盐溶液、制冷剂蒸汽共存，吸附/吸收共存）储能/制冷/制热技术。三相储能系统可利用较大的吸湿盐溶液浓度差势能与结晶热化学势能进行储能和制冷/制热，其储能密度可提高到2350kJ/kg。三相循环的吸湿量显著提高,从而可提高系统制冷制热性能。本项目旨在揭示三相储能/制冷/制热系统的基本机理。研究内容包括：复合吸湿盐吸湿和再生特性，以及其储能/制冷/制热的循环机理；吸湿剂物理参数、传热传质因素与系统性能系数的关系等。本项目为有效提高热驱动制冷系统储能效率、系统性能系数，以及以后研制高效低品位热能的综合热利用系统提供理论基础。

The fast economy development in recent decades and the predictable future keeps driving air conditioning vastly employed, which causes electricity shortage accordingly. Energy storage of industrial waste heat or solar energy for cooling and heating has been proved to be an effective way to alleviate the energy consumption pressure theoretically, whilst the low energy storage density and the low Coefficient of Performance of the thermally driven cooling system prevent the methodology from being widely applied. This project investigates the three-phase energy storage/cooling/heating technology, with the coexistence of hydrate crystalline solid, salt solution, refrigerant vapor, adsorption process and absorption process, etc., using the hygroscopic agent -water consisting of LiCl and expanded graphite. The three-phase energy storage system can achieve an energy storage density of 2350kJ/kg for cooling and heating by utilizing two sources of energy: the potential energy of concentration difference due to the salt solution, and the potential energy of chemical crystallization. The resulting cycled moisture absorption can be significantly enhanced; thus the system performance can be improved. This project aims to discover the innate properties and rules of the three-phase system of energy storage/cooling/heating. We will focus on the following aspects: studying the adsorption/absorption/regeneration characteristics of the hygroscopic agent-water and its mechanism for energy storage/cooling/heating; analyzing the relationships between the physical parameters of the absorbent, the heat and mass transfer factors and the system's coefficient of performance; investigating the thermal-dynamics characteristics of the system, etc. This project can help to effectively increase the energy storage efficiency and the coefficient of performance of the thermally driven cooling system. We believe the results of this project can also shade light on the design of highly effective systems utilizing low-grade heat in the future.