Development of a High-Density Exhaust Heat Storage System and the High-Efficiency Utilization

我们专注于硝酸镁六水合物的混合物作为基础材料和氯化镁六水合物作为添加剂储存，以利用来自新兴的热电联产系统的城市废热，通常在60-90℃的温度下可用。添加5-10重量%的后者导致调制熔点约为80℃，熔化热约为150 kJ/kg。增加混合比可使熔点降至60℃，而熔化热变化不大。重复测试表明，熔化热和熔点在1000次循环后保持其原始值。腐蚀试验结果表明，SUS 316和铝合金可以作为混合物的储槽或换热器，提出了一种高效的PCM/水混合储能太阳能热水供应系统。建造了一个示范设施，提供70个真空太阳能集热管和一个250 L的水箱和一个76 L的PCM水箱。通过计算辅助加热所消耗能量的最小点来再现测量结果。这些点存在于PCM容量与总容量的比率的0.3至0.4左右。在日本的札幌，太阳能集热系统可以满足60%的年热水供应需求，在日本南部的其他城市，太阳能集热系统可以满足70%以上的年热水供应需求。由于自然对流的影响，在使用矩形翅片的条件下表现出最高的性能，而圆形翅片在使用实心PCM的条件下具有优势。使用实际储罐的实验结果表明，在7 L/min的流速下，与水存储相比，PCM存储中可以回收15%的热量。

We focused on a mixture of magnesium nitrate hexahydrate ass base material and magnesium chloride hexahydrate as an additive to store in order to utilize urban waste heat from emerged co-generation systems, typically available at temperatures of 60-90℃ Addition of 5-10 wt% of the latter resulted in a modulated melting point of around 80℃ and a heat of fusion around 150 kJ/kg. Increasing the mix ratio allowed the melting point to be decreased to 60℃, whereas it caused little change of heat of fusion. Repeat tests showed that the heat of fusion and melting point retained their original values after 1000 cycles. Results from corrosion tests showed SUS316 and aluminum can be used as build storage tanks or heat exchangers for the mixture.A high efficient solar hot water supply system with PCM/water hybrid thermal energy storage system was proposed. A demonstration facility which provides 70 evacuated solar collector tubes and a water tank of 250L and a PCM tank of 76L, was constructed. Measurements were reproduced by calculations in terms of minimum points of consumed energy for auxiliary heating. The points existed around 0.3 to 0.4 of the ratio of PCM capacity to total capacity. The solar thermal system could cover 60% of the annual heat demand for hot water supply in Sapporo, Japan Moreover, over 70% of the heat demand can be covered by the system in other southern cities of Japan.Microcapsule Slurry PCM (MCS-PCM) was also applied to the system. The highest performance was shown under conditions with rectangle fins because of the effect of natural convection, whereas round shape fins had the advantage in conditions with a solid PCM. The results of experiments using an actual storage tank showed that 15% larger heat can be recovered in the PCM storage compared to the water storage at the flow rate of 7L/min.