通过大规模跨季节储热系统对工业余热与太阳能进行存储并用于城市集中供热，可以实现“夏热冬用”，提高系统利用率和传统能源替代率，具有广泛的应用前景。但要将其在实际工程中规模化应用，尚需解决以下三个方面的问题：首先，在储热装置设计优化方面，目前缺少基于减少储热装置热量品位损失的优化方法和评价指标；其次，缺少多热源跨季节储热系统的热源整合与参数匹配设计方法；最后，跨季节储热是一种典型的长周期、大空间换热问题，储热装置的出水温度在一个运行周期内随土壤温度的变化而持续变化。而工业余热系统往往对于回水温度的稳定性有较高要求，特别是在涉及到多热源整合的前提下，储热系统出水温度的长周期变化会对热源整合及余热回收产生影响。针对上述问题，本文针对经济性和推广性都较优的地埋管跨季节系统开展了如下几方面的研究：第一，基于火积 分析法，对地埋管跨季节储/取热过程中的各项损失进行拆分和刻画。基于温度-热量（T-Q）图对储/取热过程的不可逆损失进行分析，提出了评价储热系统的热性能的指标，并以此为优化目标给出了地埋管跨季节储热装置的优化原则和方法。 第二，基于夹点分析法和T-Q图，对多热源跨季节储热系统的热源整合及参数匹配进行研究，给出了热源整合的设计原则及方法。提出了利用地埋管储热装置分区控制策略实现储热装置长周期动态特性与热源动态特性匹配的方法。给出了储热系统参数匹配的设计流程及设计方法。第三，设计并搭建了国内首个成功运行的工业余热与太阳能跨季节储热示范工程，并对该示范工程的储热-取热周期运行结果进行了详细测试。工程总储热体积达50万m3, 经过1年左右的预热期运行，平均土壤温度从初始地温（10℃）升高至37℃，核心区域土壤温度升高至40℃。该工程为研究跨季节储热系统的关键技术与工程应用提供了完整的实验平台。
Seasonal thermal energy storage is an effective way for integrating renewable energy and waste heat into urban district heating systems. Among all the technology forms, borehole thermal energy storage (BTES) is a solution with both good economy and applicability. There are three key questions that need to be solved for integrating industrial waste heat and solar energy through the use large scale borehole thermal energy storage. First, for the design and optimization of the borehole thermal energy storage, a thermal performance indicator is needed for evaluating the the loss of energy grade through the heat injection and extraction process. Common performance indicator, such as thermal storage efficiency, could be merely adopted for evaluating the quantity loss of energy. Secondly, an industrial waste heat heating system with seasonal thermal energy storage always contains several heat sources with different energy grade and supply charateristics. The integration of heat sources need to be opitimized with certain principles and methods to improve the thermal performance of the overall system. Third, the long-term heat transfer of the borehole thermal energy storage is an infinite heat transfer problem. The output temperature of the borehole thermal energy storage tends to change continuoursly with the heat injection and extraction operation. How to match the long-term dynamic property of the borehole thermal energy storage with different heat sources is a question need to be solved in system design, or the long-term variation of the output temperature of the borehole thermal storage will affect heat integration and heat recovery.Aiming at these three questions, the following works have been done in this paper:First, the loss energy grade in different system links are studied based on entransy analysis. By depicting the entransy loss in the heat injection/extraction process on the T-Q diagram, the definition of entransy efficiency of seasonal thermal storeage is proposed for design and optimization. Second, based on the pinch analysis method and T-Q diagram, the integration of multiple heat sources and seasonal thermal energy storage is studied. Basic ingtegration principles and method are proposed through case study.Third, as a new attempt to explore the effective utilization of renewable energy and industrial waste heat through seasonal thermal energy storage. A demonstration project of large scale borehole thermal energy storage integrated district heating plant was proposed and built by us. In the demonstration project, solar energy and industrial waste heat are integrated into the city heating network through the use of 500,000m3 borehole thermal energy storage. Long-term monitoring results showed that 33459 GJ heat was stored underground during the first year heat injection operation. The average ground temperature of the storage was elevated from 10 ℃ to around 37 ℃, and the core temperature was improved to around 40 ℃.
