Abstract:

Experiments are performed on the effect of local cooling by thermoelectric cooler on triggering solidification of supercooled sodium acetate trihydrate (SAT). Factors such as the water content, the SAT sample mass as well as the input power of the thermoelectric cooler are examined about their effects on the crystallization activation and discharging characteristics. The results showed that with the increase of water content, the overall crystallization induction period increased, the heat release temperature decreased, and the water content of 44% was used as the ideal system ratio. The crystallization induction period was 2 min and the stable exothermic temperature was 52.8℃. The higher the input power(P) is, the faster the unit is cooled and the induction time period for P=280 W is one third of that for P=70 W. The probability of nucleation of samples is increased for higher sample mass and then the induction time is shorter with higher discharging temperature and longer heat release time.

Key words: local cooling, sodium acetate trihydrate, stable supercooling, crystallization, phase change, water content, solar energy

摘要：

利用半导体制冷局部低温诱发稳定过冷的三水醋酸钠溶液凝固，实验研究不同含水量、样品质量、输入功率等条件下过冷溶液结晶诱导期及释热特性。结果表明：随样品含水量增加，整体呈现结晶诱导期增加，释热温度下降的趋势，含水量44%作为较理想的体系配比，结晶诱导期为2 min，稳定放热温度达52.8℃；诱发过程中制冷装置输入功率越大，容器壁面降温越快，较容易触发，功率为280 W的结晶诱导期是功率为70 W的 1/3；样品质量越大，结晶诱导期越短，稳定放热温度相对较高，放热时间趋长。实验结果为稳定过冷水合盐局部低温诱发凝固释能系统设计提供依据。

关键词: 局部低温, 三水醋酸钠, 稳定过冷, 结晶, 相变, 含水量, 太阳能