跨季节复合储热系统储/释热特性

Storage and release characteristics of seasonal composite thermal storage system

太阳能等可再生能源具有间歇性和不稳定性等特点,导致其在供给侧和需求侧存在时间、空间和强度上的不匹配特性和季节性,跨季节储热技术是解决上述问题的最有效方法之一。然而传统的跨季节储热系统存在热损失大、系统效率低等问题。为了解决上述问题,本文提出了由地埋管储热和水箱储热相耦合的新型复合储热系统,采用实验研究和数值计算的方法对该复合储热系统储释热特性和耦合储热体温度场变化规律开展研究。结果表明,该新型复合储热系统技术上是可行的,两种储热方式互为补充、互为协调,热量损失小,系统能效高,效率达67.29%,且耦合储热体温度场相互叠加,更有利于热量的高效存储与释放。此外,复合储热系统经过储热、保温、释热和恢复四个阶段后,耦合储热体温位水平升高,更有利于系统多年运行。本研究有助于拓展和完善地下跨季节储热系统能量传输和传热控制理论,为进一步拓展应用提供理论指导依据。

Renewable energy sources,such as solar energy,have the characteristics of intermittence and instability that lead to their temporal,spatial,and intensity mismatch and seasonal characteristics.The seasonal thermal storage technology is one of the most effective solutions for these problems,but the traditional seasonal thermal storage system encounters problems of large heat loss and low system efficiency.To solve these problems,this study proposes a new type of composite thermal storage system coupled with an underground borehole storage and a water tank thermal storage.This system uses Fluent simulation software to perform research on the thermal storage and release characteristics of the composite thermal storage system and the change law of the temperature field of the thermal storage body.The results show that the new composite thermal storage system is technically feasible with a 67.29%system efficiency.The two thermal storage methods are complementary and coordinate with each other.The temperature fields of the coupled thermal storage bodies are superimposed on each other,thereby showing a significant temperature delay,and are more conducive to the thermal storage and release.In addition,after one operating cycle of the composite thermal storage system,the temperature level of the coupled thermal storage body increases,which is conducive to the system operation for many years.This research will be helpful in expanding and improving the energy transmission and heat transfer control theory of the underground seasonal thermal storage system and provide theoretical guidance for further expansion and application.