Abstract: In solar energy heat-collecting system, temperature stratification effect of the storage tank is greatly influenced by different tank structures. A test rig of storage tank was established in order to study the stratification characteristics. Experiments of three different structure tanks (direct import, three layers and stratifier)were carried out. The initial water temperature in the tank is 70℃. Under the same inlet water temperature and different quantities of flow rate, the temperature variation curves of each layer in different structure tanks were drawn according to the experimental data. Results showed that with the increase of influent flow rate, the mixing effect in the storage tank is strengthened and the temperature of each layer tends to be consistent with less time. Based on the law of thermodynamics, the indexes of stratification effect such as extraction efficiency, dimensionless exergy and stratification number of these tanks were analyzed. Results also showed that among these different structure tanks, the stratifier has a best stratification effect and effectively inhibits the mixing effect. Besides, three layers tank has a better stratification effect than the direct import ones.

Key words: water storage tank, stratification effect, extraction efficiency, dimensionless exergy, stratification number

摘要： 在太阳能集热系统中，储热水箱内的温度分层效果受不同水箱结构的影响巨大。为研究这一特性，搭建了一套储热水箱分层特性测试实验台，对直接进口式、三层孔板式和盒状结构水箱进行了测试实验。水箱内初始水温为70℃，在相同的进水温度和不同的流量条件下，根据实验数据绘制了不同结构水箱内的各层温度变化曲线。结果显示，进水流量越大，水箱内混合效应越大，各层温度趋于一致的时间越短。在热力学定律的基础上，计算并分析了3种结构水箱的取出效率、（火用）和Str数等分层特性指标。结果表明，3种结构中，盒状结构水箱内的温度分层效果最好，对热量的利用率最高，盒装结构有效地抑制了冷热水混合效应，其次为三层孔板式水箱，而直接进口式水箱的温度分层效果最差。

关键词: 储热水箱, 分层效果, 取出效率, (火用), 分层数