相变材料墙体节能效果的实验

Experimental Study on Energy-Saving Effects of the PCMWall

目的研究相变材料应用于墙体内侧时,墙体在不同条件下传热系数的大小,提出以传热系数减少率作为节能效果的评价指标,考察墙体的节能效果.方法根据相变材料的节能特性,建立节能测试系统,利用变温法对复合墙体进行传热系数的测试,通过升温、恒温、降温实验,对相变墙体的节能效果进行探讨.结果随着墙体热阻的增大、升温速率的减小、相变材料掺量的增加,相变墙体的节能效果增大.保温层厚度为25 mm、升温速率为1.3℃/h时,相变墙体的节能效果最大,即在节能效果为50%的基准墙体基础上节能38.2%.结论提出了墙体的节能性能评价指标,节能效果β=K基准-K实测K基准×100%.墙体的节能效果与墙体热阻、升温速率、相变材料掺量密切相关,墙体热阻大、升温速率慢、相变掺量高其节能效果好.

The aim of this paper is to study heat transfer coefficient of the wall, where the phase change material(PCM) is applied in its inside. The loss rate of heat transfer coefficient as an evalu- ation index was proposed for examining energy saving effects of the wall. According to energy- saving features of PCM, a system for testing and measuring was built. Using the method of variable temperature, the heat transfer coefficient of composite wall was measured. And energy-saving effects of the phase change wall were discussed by tests of warming-up, constant temperature and cooling. A calculating formula for energy saving x 100% was given. It is found that with increase of the wall thermal resistance and the content of PCM, in the case of a small rate of warming-up,energy saving effects is 25 mm,the warming-up rate is 1.3 ℃/h,the maximum energy saving effect is achieved. In compassion with the benchmark wall which has energy saving rate 50% ,the phase change wall can further save energy 38.2%. Conclusion is that the proposed energy conservation performance evaluation index of the wall is reliable. Energy saving effects of the wall are closely related to the thermal resistance, wanning-up rate and the content of PCM. When the thermal resistance is large, the warming-up rate is small and the content of phase change is high, good energy saving effects can be achieved.