有效而廉价地降低建筑围护结构负荷是降低空调供暖能耗的重要途径。围护结构的夏季温度较高，冬季温度较低，自然环境的冷热源具有调节围护结构温度的潜力。基于此，本文提出了嵌管式玻璃围护结构的概念，研究了利用自然能源降低建筑围护结构负荷的方法。通过实验与模拟分析了嵌管式围护结构的传热过程、节能效果及对室内环境的影响。内容总结如下：（1）实测了一幢典型玻璃幕墙建筑各朝向房间在各季节的自然室温和负荷。发现房间冷负荷超过80 W/m2，室温可在一小时内升高6 ℃，而降温缓慢；各朝向的负荷差异巨大。传统遮阳和保温等方式效果有限。鉴于此，本文提出了嵌管式玻璃围护结构，结合主被动技术，可利用自然能源降低负荷。为验证其有效性，加工了嵌管窗样品，搭建了可进行全年、不同朝向实验的嵌管式实验舱和传统实验舱。实测表明，嵌管窗冬季可比传统窗温度提高6~15 ℃，夏季可降低8~15 ℃。低于室温的水可在冬季供热，14 ℃的水即可实现外温0 ℃时自然室温不低于11 ℃。高于室温的水可在夏季供冷，28 ℃的水即可降低58%的窗户传热。自然能源的利用范围得到扩展。（2）为探究嵌管式围护结构对室内热环境和空气品质影响，搭建了可模拟不同围护结构的室内环境舱。通过暖体假人、示踪气体及热环境测试发现，采用传统窗户的房间辐射不对称性较大，送风射流被破坏，空气扩散系数低于80%，吹风感风险达30%；置换通风气流组织也被强热羽流破坏。嵌管式窗户可营造更为舒适的室内热环境，如把窗户温度控制在27.5 ℃时工作区温度的标准差仅为0.1 ℃，假人的各区块温度分布均匀；并可与置换通风结合来改善空气品质，人员吸入无量纲污染物浓度低于0.5。（3）为进一步分析嵌管式围护结构的传热过程与节能效果，建立了嵌管式窗户和墙体的数值计算模型，并对方法进行了实验验证。模拟分析表明，夏季嵌管窗通常应关闭开口以避免带入热量，并可减小宽度节省空间。对于墙体，由于保温性能较好，嵌管所引起外壁面传热增加有限，效率较高。水温是嵌管性能的最大影响因素。能耗分析表明，嵌管式空调系统减少了换热环节和掺混损失，总能耗降低32.5%，能效比可达9.7。嵌管式围护结构在我国各气候区应用的负荷降低率在20~70%，节能率在15~50%。
An important approach for improving building energy efficiency is to reduce the load through building envelope effectively. The temperature of envelope is high in summer and low in winter. Thus, natural cooling or heating sources have the potential to regulate the temperature of envelope. Based on this, the idea of a pipe-embedded glass envelope was proposed in this study and the method of utilizing natural energy to reduce the load from building envelope was investigated. The heat transfer process, energy saving performance, and impact on indoor environment of the pipe-embedded envelope were analyzed by experiments and simulation. The main work is summarized as follows:(1) The free-running temperatures and loads of rooms on different orientations in a typical glass building were tested. It was observed that the cooling load of room could be higher than 80 W/m2 and the room temperature rose 6 oC in one hour but decreased slowly. The loads of rooms on different orientations had big difference. The effect of traditional shading and insulation was limited. Thus, a pipe-embedded glass envelope was proposed in this study, which integrated passive and active technologies and aimed to utilize natural energy to reduce load. To verify its effectiveness, a sample of pipe-embedded window was manufactured and the corresponding experimental chambers were built. The experiments showed that, compared with the traditional window, the temperature of the pipe-embedded window was increased by 6~15 oC in winter and decreased by 8~15 oC summer. The water cooler than indoor space was able to heat the room in winter. The water of 14 oC was adequate for maintaining the room over 11 oC when the outdoor temperature was 0 oC. The water warmer than indoor space was able to cool the room in summer. The water of 28 oC was adequate for reducing the load of window by 58%. The range of serviceable natural energy sources were extended.(2) An environmental chamber was built to investigate the influence of a pipe-embedded envelope on indoor thermal environment and air quality. Thermal manikins and tracer gases were employed in the study. The results showed that, in the condition with traditional window, the indoor radiant temperature asymmetry was larger, the supply air jet was disturbed, the air diffusion performance index was less than 80%, and the draft rate was over 20%. The air distribution of displacement ventilation was destroyed. The pipe-embedded window helped to create a better indoor thermal environment. When the window temperature was controlled at 27.5 oC, the standard deviation of occupied zone was only 0.1 oC and the temperature distribution of manikin body segments was uniform. The pipe-embedded window can be integrated well with displacement ventilation to improve air quality. The normalized inhaled containment concentration was less than 0.5.(3) The numerical models of pipe-embedded window and pipe-embedded wall were built to further study the heat transfer process and energy saving performance of pipe-embedded envelope. The accuracy of the models has been verified by experiments. The simulation results showed that the pipe-embedded window should close the openings of external skin to avoid the incoming of additional heat. And the cavity depth can be reduced to save space. For a pipe-embedded wall, owing to the better insulation effect, the increase of heat flux on the external surface was limited and the effectiveness was high. The energy analysis showed that the heat transfer loops and mixing loss in a pipe-embedded air-conditioning system was reduced. Thus, the total energy consumption was decreased by 32.5% and the coefficient of performance was over 9.7. The reduction rate of load was 20~70% when the pipe-embedded envelope was applied in different climatic regions in China. And the energy saving rate was 15~50%.
