【作者】 郭伟杰；

【导师】 徐士鸣；

【作者基本信息】 大连理工大学 ， 制冷及低温工程， 2008， 硕士

【摘要】 本文介绍了一种以氨水溶液为工质的多温级蓄能制冷方法和工作流程,主要用于工业和商业领域内需要多个制冷温度等级的蓄能制冷系统。其工作原理是将用电低谷的电能通过压缩机将其转换成氨水溶液的制冷潜能并储存在溶液储罐内,当用户需要一个或一个以上温度等级的冷能时,采用逐级蒸发、吸收的方法将储存的制冷潜能转换成所需的冷能。蓄能制冷系统充分利用用电低谷的电能对电网起到移峰填谷的作用,能量转换效率高,费用低,工作灵活,设备简单,潜能可长久储存,制冷温度低并可同时提供多个制冷温度等级,特别适用于多温级冷库或多温级工业用冷的场合。在建立氨水物性参数计算程序和系统充、释能过程动态模型的基础上,以长江流域某一典型的两温级冷库作为算例,对多温级蓄能制冷系统在全量蓄能策略下能量转换及储存过程进行数值模拟,得到系统各设备负荷的大小和变化特性、循环工作参数随时间和外部条件的变化规律。研究结果为了解多温级蓄能制冷系统的运行特性,系统设计和设备选型以及制定动态控制方案提供帮助。本文还以全量蓄能策略为例,讨论了回热器对系统COP的影响,循环COP和蓄能密度与溶液质量分数差的关系,以及冷却水进口温度和冷库相对负荷变化时,多温级蓄能制冷系统溶液初始充注参数的变化和系统COP的变化,通过对两种不同工作流程的比较分析,发现充能过程压缩机工作而吸收器不工作的流程较适合于需要更低温度等级的冷库蓄能制冷系统。所得出的这些结论,可以为多温级蓄能制冷系统的深入研究提供一定的理论思考和思路。更多还原

【Abstract】 An introduction dealing with the refrigeration method and the working flow of multistage energy storage system using NH3-H2O as working fluid is presented, which is mainly applied in the industrial and commercial energy storage refrigeration system. The principle of the system states that the off-peak electricity is transformed into the refrigerating potential of aqueous ammonia, and stored in solution storage tank. The stored potential can be transformed into cold energy by means of gradual evaporation or absorption, when needing one or multistage cold energy. The system can be utilized to shift electricity load from on peak periods to off peak periods, and has many advantages such as large energy conversion efficiency, low cost, flexible operating mode, simple storage equipment, and multistage range temperature, which make it especially applicable in multistage cold storage or industrial cooling.Based on the computation of ammonia-water thermodynamic properties and the dynamic models of the system working process, the energy transformation and storage dynamic processes according to a typical two-stage cold storage located near by Yangzi River are numerically simulated under the full storage strategy. The regulations or relationships between the main working parameters during the energy charging or discharging time, and the load capacity and variation characteristics of the devices, are obtained by simulation. All these results are useful for understanding of operation characteristics, design or selection of the devices, and also helpful for designing the dynamic control program of the multistage energy storage refrigeration system.In this paper, the influences of reheater on COP, the relations between the increment of solution concentration and COP or storage density, the influences of inlet cooling water temperature and relative cooling load on the parameters of working solution charged into the system and on COP of the system are also discussed. These conclusions provide some theoretical references for the deep research of the multistage energy storage refrigeration system.更多还原