Abstract The quality of output temperature is one of the key parameters for the reliability of water heating system. In this work a simulation work was done to regulate the output temperature in a novel water heating system using solid graphite as thermal energy storage medium. The effects of water tank on the quality of output temperature was considered. Two different strategies were thus considered: (i) single tank system, and (ii) double-tank system. And two different working conditions were analyzed: (i) standard design condition, and (ii) demand change conditions. The results showed that the application of water tanks can reduce the standard deviation of output temperature by 68.49% and 68.81% under the standard design condition, respectively. And the improvement is highly related to the capacity of hot water tank. For the demand change condition, the regulation strategy was carried out based on the criterion of heat power equilibrium. The results showed that the single tank system will deteriorate the reliability of water heating for demand change condition, though it can reduce the oscillation of the output temperature. For the double-tank system, a two-step adjustment method was applied. The results showed that the average output temperature can be quite close to the target value when demand ratio changes to 0.8 and 0.9. And the standard deviation of temperature has also reduced by 24.19% and 63.06%, respectively.

中文翻译：

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使用固体石墨作为显热蓄热介质的新型水加热系统中输出温度的调节：水箱的影响

摘要 输出温度的好坏是影响热水系统可靠性的关键参数之一。在这项工作中，通过模拟工作来调节使用固体石墨作为热能存储介质的新型水加热系统中的输出温度。考虑了水箱对输出温度质量的影响。因此考虑了两种不同的策略：（i）单罐系统，和（ii）双罐系统。并分析了两种不同的工作条件：（i）标准设计条件，和（ii）需求变化条件。结果表明，在标准设计条件下，水箱的应用可使输出温度的标准偏差分别降低68.49%和68.81%。而这种改进与热水箱的容量密切相关。针对需求变化工况，基于热力均衡判据实施调控策略。结果表明，单水箱系统虽然可以减少输出温度的振荡，但会降低需求变化条件下水加热的可靠性。对于双罐系统，应用了两步调整方法。结果表明，当需量比变为0.8和0.9时，平均输出温度可以非常接近目标值。温度的标准偏差也分别降低了24.19%和63.06%。虽然它可以减少输出温度的振荡。对于双罐系统，应用了两步调整方法。结果表明，当需量比变为0.8和0.9时，平均输出温度可以非常接近目标值。温度的标准偏差也分别降低了24.19%和63.06%。虽然它可以减少输出温度的振荡。对于双罐系统，应用了两步调整方法。结果表明，当需量比变为0.8和0.9时，平均输出温度可以非常接近目标值。温度的标准偏差也分别降低了24.19%和63.06%。