热激活相变复合墙体动态热特性与节能潜力

为提升老旧建筑热工性能，基于中国北方清洁供暖背景，提出一种利用夜间低谷电力制取低品位热水作为热源，进行蓄能的热激活相变建筑系统。建立了典型热激活相变复合墙体传热模型并与参照实验进行验证，在寒冷地区供暖季气候条件下，模拟分析了管间距、相变层厚度和朝向等因素对复合墙体热特性以及节能潜力影响。结果表明：将集成内嵌管的相变夹层置于墙体与外保温之间具备技术可行性，可大幅提升墙体热工性能；以南墙为例，因墙体引起的热负荷和一次能源消耗分别减少105.5%和14.07%；管间距相比相变层厚度影响更为明显，综合考虑热阻及蓄放热特性，管间距100 mm和相变层厚度30 mm较优；朝向对复合墙体影响较大且北墙提升最为明显，与南墙相比其一次能源消耗和运行费用减少率分别高出20.3和9.0个百分点。研究结果为热激活相变围护结构设计及其在清洁供暖和超低能耗建筑应用中提供了参考。

Thermal performance and energy saving potential study on a thermo-activated PCM building system

Based on the clean energy heating context in China, a novel thermo-activated PCM composite building envelope system was proposed to further reduce building energy consumption and improve indoor comfort by utilizing low-grade hot water produced by valley current. A comprehensive heat transfer model was built and validated by comparing with reference test results. Under the condition of heating season in cold area like Tianjin, the effects of pipe spacing, PCM thickness and orientation on thermal behavior and energy saving potential were numerically investigated. The results show that the thermal performance of the composite wall has been changed, and the primary energy as well as the operation cost, taking south wall for example, are reduced by 14.07% and 56.03%, respectively. The pipe spacing shows a more obvious influence than PCM thickness, thereby 100 mm for pipe spacing and 30 mm for PCM thickness seem to be the satisfactory values when taking the thermal resistance and heat charge/discharge into account simultaneously. Orientation has big influence on the performance and the improvement in north orientation is most obvious among the four orientations. The primary energy and operation cost saving ratio in north orientation show a reduction by 20.3 and 9.0 percent respectively compared with that in south. This study can provide reference for pipe-embedded PCM envelope design and its application to buildings of clean heating and low energy consumption.