高大空间中辐射地板供冷动态特性研究

In recent years, large space buildings (e.g., airport terminals and railway stations) have been built in many cities. The interior heat sources of these buildings are quite complex, and the adoption of conventional air conditioning systems in large spaces leads to significantly higher energy consumption. Therefore, promoting energy efficiency in these buildings to reduce their energy consumption is tremendously important. A radiant floor is an effective sensible heat removal terminal due to its direct absorption of solar radiation and longwave radiant heat exchange with the wall surfaces. In this project, from the perspective of heat transfer, detail analysis model of heat removal process in the large spaces will be constructed to analyze the suitability of different cooling methods for different types of heat sources. As to the application of radiant floor cooling in large spaces with high-intensity solar radiation, the thermal mechanism of cooling capacity enhancement will be dissected, and proper indicators will be put forward to reflect the dynamic heat transfer performance. On this basis, the analysis method of the overall dynamic performance of radiant floor and building will be established, providing guidance for the choice of radiant floor structure under different application conditions and the performance optimization of radiant cooling system.

近年来航站楼、客站等高大空间建筑蓬勃发展，其室内热源状况复杂、空调系统运行能耗较高，降低其能耗对推进建筑节能工作具有重要意义。对于排除高大空间中的太阳辐射和高温壁面传热，辐射地板供冷具有较大应用潜力。本项目将从热量传递的视角，对高大空间中热量传递过程进行深入研究，明确不同类型热源适合的供冷方式；针对辐射地板供冷在高大空间中的应用，剖析瞬时强太阳辐射下辐射地板换热能力增强的机理并提出能够反映其动态传热性能的指标；在此基础上，建立辐射地板与建筑结合的整体动态分析方法，为不同应用条件下辐射板的选择、辐射供冷系统的整体优化提供指导。

高大空间中热源状况复杂、运行能耗高，采用辐射地板供冷具有显著的节能潜力。本项目针对高大空间的复杂热源情况，研究了辐射地板供冷能力增强的机理、动态传热性能的表征方法以及与建筑结合的整体动态性能。主要成果包括：1）从热量和品位两方面描述高大空间中各类热源特征，建立了从室内多个热源—供冷末端—冷源的传热分析模型，形成了以选取适宜末端方式为基础的高大空间空调系统指导原则，即在满足室内人员体感温度要求的前提下，减少传热量、提高所需的冷源温度；2）定量分析和比较了喷口送风方式和辐射地板方式的热量采集特性，剖析了辐射末端在处理高温壁面传热和瞬时太阳辐射热量方面的优势；3）针对高大空间中瞬时强太阳辐射对辐射末端的影响，根据周期性蓄热-释热过程的分析，定义了辐射末端在太阳辐射期间的等效热阻来反映其动态性能，将太阳辐射的瞬态过程与稳态换热过程统一分析；4）采用状态空间法建立了建筑与辐射供冷末端结合的整体动态传热计算模型，得出了太阳入室辐射得热强度、时间分布对辐射地板的间歇运行特性的影响规律，形成了考虑太阳辐射得热的辐射地板间歇运行策略。研究成果从热量传递的视角审视不同供冷方式的差异，定量分析不同传热过程中传热温度损失和传热量差异，可为构建适宜的末端方式、实现“高温供冷”提供了理论指导；明晰了辐射地板的辐射传热和蓄热特性对于增强其处理太阳辐射热量能力的机理，对辐射地板的动态换热性有更深入的认识；综合考虑室内负荷变化（如太阳辐射）和间歇运行的影响，评价高大空间中辐射地板供冷其在运行周期内的整体性能，为不同应用条件下辐射板的设计选择、辐射供冷系统的性能优化提供理论依据。