Development of magnesium oxide/water chemical heat pump

设计了一个实验室规模的氧化镁/水化学热泵系统，其热输出为100 W级。由于反应物材料和系统对重复运行的耐久性是热泵发展的重要问题，因此对重复运行的性能进行了论证，开发了一种具有重复反应耐久性的新型反应物材料。将该材料用于实验室热泵，在热泵实验中，直接同时测量了反应分数和热输出。在前者之后，用称重传感器测量重量变化。后者用安装在反应器中的加热管测量。从第一次重复操作到第三次重复操作，测得反应性下降约20%，但在第十次重复操作之后，反应性稳定。结果表明，该热泵系统在实际重复利用中是可行的，在第一次重复利用中，系统能够储存430 ℃左右的热能，并从70-90 ℃的低温蒸汽中提供75-120 ℃的热能，在最初的60分钟内，每公斤初始氢氧化镁的热功率超过50- 100瓦。采用二维数值模拟方法对反应器内的反应速率和传热过程进行了模拟。实验和模拟结果表明，该热泵系统具有足够的蓄热能力和热功率，可以作为商业系统使用。

A laboratory scale system of Magnesium oxide/water chemical heat pump was designed for the heat output o 100W class. The performance of the repetitive operation was demonstrated because the durability of the reactant material and the system to the repetitive operation was important matter for the heat pump development.A new reactant material which had a durability to repetitive reaction had been developed in this work. The material was used for the laboratory heat pump.On the heat pump experiment, the fraction reacted and heat output were measured directly and simultaneously in the experiment. The former was followed by measurements of weight change with a load cell. The latter was measured with a heating tube installed in the reactor. From the first to the third repetitive operation, the decrease of reactivity about 20% was measured, but after the time to the tenth, the reactivity was stable. The result showed the feasibility of the heat pump for practical repetitive utilization.On the first repetition, it was shown that the system was able to store a thermal energy at about 430ﾟC and to supply a thermal energy at 75-120ﾟC from a low temperature steam at 70-90ﾟC,and that the thermal power exceeded 50-100w per 1kg of initial magnesium hydroxide during the first 60minutes. The profile of reaction rate and heat transfer in the reactor were simulated by two-dimensional numerical analysis. The results of the experiments and the simulations showed that the heat pump had enough thermal storage capacity and thermal power as a commercial system.