下送风辐射供冷房间室内温度非均匀分布特性及优化调控机理研究

Thermal stratification exists in a room with underfloor air supply system and radiant cooling system, and the distribution of indoor temperature is non-uniform. There was a lack of rational method of optimal regulation of indoor temperature for the underfloor air supply system combined with radiant cooling system, which was not benefit for the development of the hybrid system. In order to solve this problem, the hybrid system with underfloor air supply system and ceiling radiant cooling system was selected as the research objective in this program, and the experimental study integrated with numerical simulation and theoretical analysis were used as the research method. Firstly, the quantitative analysis of effect of underfloor air supply parameters and radiant cooling surface temperature on the performance of non-uniform distribution of indoor temperature was performed, then the flow mechanism of indoor air was pointed out and a nodal model to predict the non-uniform distribution of indoor temperature was established. Secondly, the effect of cooling load of building envelop on human thermal comfort was studied, then the comfort ranges of underfloor air supply parameters and radiant cooling surface temperate were obtained. Finally, the interrelation between the flow of indoor air and the heat transfer of building envelope was analyzed, then the relationship between the optimal underfloor air supply parameters and radiant cooling surface temperature and the cooling load of building enveloped was established. The research results of this program can be the theoretical foundation for the optimal regulation of indoor temperature and for the operation of the hybrid system with underfloor air supply system and radiant cooling system, and can be benefit for the extensive application of the hybrid system to solve the problems with regard to energy and environment.

下送风辐射供冷房间室内空气存在明显的热力分层，导致室内温度呈非均匀性分布。至今缺乏合理的非均匀室内温度优化调控相关理论方法，严重阻碍了下送风辐射供冷复合空调技术的发展。针对上述问题，本项目以地板送风与顶板辐射供冷房间为研究对象，拟采用实验研究、数值模拟及理论分析相结合的方法，定量分析送风参数及辐射供冷表面温度变化对室内温度非均匀分布的影响，揭示室内空气热分层流动规律，构建合理的室内温度非均匀分布预测模型；研究不同围护结构负荷条件下人体热舒适性的变化规律，明确送风参数及辐射供冷表面温度的舒适变化范围；阐明室内空气热分层流动与建筑能量传递耦合作用关系，建立最佳送风参数及辐射供冷表面温度与围护结构负荷之间定量关系。本项目的研究成果为下送风辐射供冷房间非均匀室内温度优化调控及复合空调系统高效运行提供理论依据，推动下送风辐射供冷复合空调技术在工程中的广泛应用，对缓解社会能源及环境问题具有重要意义。

至今缺乏合理的下送风辐射供冷房间非均匀室内温度优化调控相关理论方法，严重阻碍了下送风辐射供冷复合空调技术的发展。针对上述问题，本项目以地板送风与顶板辐射供冷房间为研究对象，通过实验研究系统分析了辐射顶板表面温度及送风参数的变化对非均匀室内热环境的影响规律，建立了非均匀室内热环境预测模型；通过分析辐射顶板表面温度及送风参数对人体热舒适的影响，得到了人体热舒适条件下辐射顶板表面温度及送风参数的变化范围；分析了典型建筑气候区室内温度控制参数对室内温度及建筑能耗的影响，确定了不同建筑气候区辐射供冷系统供水温度最佳控制策略。. 主要结论如下：（1）在1.3m以下室内温度沿高度方向呈现正温度梯度，在1.3m以上随着顶板温度升高，室内温度逐渐由正温度梯度转变成负温度梯度。围护结构负荷对室内温度沿高度方向的分布具有较大的影响，在总负荷一定的情况下室内负荷或者围护结构负荷的变化对沿高度方向室内温度分布基本没有影响。（2）不同围护结构负荷下辐射顶板表面温度及送风参数的变化对室内受试者热感觉、热舒适等主观感受及人体生理参数都没有显著的影响，人体热舒适条件下辐射顶板表面温度及送风量的变化范围分别为15~23℃及10~19.2h-1。（3）室内温度控制效果最好的控制策略是以室内操作温度作为反馈量的供水温度PID控制策略，而建筑能耗最小的是供水流量PID控制+启停控制策略。. 本项目的研究成果为下送风辐射供冷房间非均匀室内温度优化调控及复合空调系统高效运行提供理论依据，推动下送风辐射供冷复合空调技术在工程中的广泛应用，对缓解社会能源及环境问题具有重要意义。