Characteristics of Plate-Fin Heat Exchanger with Phase Change Material

潜热聚变能系统是有用的，因为它们能够连续地向低温流体提供热能，即使高温流体的热量供应随时间而变化。本文研究了一种相变材料板翅式换热器。目前的热交换器由310根边长为9.5毫米、厚度为0.5毫米、长度为300毫米的铜方管制成，为单道横流型，两种流体（空气）未混合。采用熔合温度为28.0℃的正十八烷作为PCM。将2.13 kg的PCM填充在154管中。进行了三种实验，测量了PCM的进出口温度和内部温度。在第一次实验中，得到了稳态下的效率和总换热系数。板式翅片提高了约10%的效率。通过稳态三维热传导计算，得到了空气的尺寸、热性质和传热系数等参数对整体传热系数的影响。在第二个实验中，由于高温气流停止，低温气流的出口温度保持在恒定温度90-150分钟。在第三个实验中，高温空气以等间隔间歇流动。流速均为4001 /min，空气入口温度分别为70℃和10℃，周期为2小时。低温空气出口温度在20℃<正负> ~ 2.5℃之间。上述瞬态和周期试验表明，该PCM换热器具有良好的潜热储存特性

Latent heat-of-fusion energy systems are useful, because they are able to supply continuously the thermal energy to the lower-temperature fluid even when the supply of heat from the higher-temperature fluid varies with time. In the present report a plate-fin heat exchanger with a phase change material (PCM) was studied. The present heat exchanger, which was made with 310 copper square-tubes with 9.5 mm sides, 0.5 mm thickness, and 300 mm length, was a single-pass cross-flow type, both fluids (air) unmixed. The n-octadecane, of which the fusion temperature is 28.0 C, was used as the PCM. The 2.13 kg PCM was filled in the 154 tubes. three kinds of experiments were carried out and the inlet and outlet temperatures and the temperatures in the PCM were measured. In the first experiments, the effectiveness and the overall heat-transfer coefficient were obtained at steady states. The plate-fin improved the effectiveness by about 10 %. By the calculations of steady three-dimensional heat conduction, the effects of the parameters, --- dimensions, thermal properties, and heat transfer coefficients of air ---, on the overall heat-transfer coefficients were obtained clearly. In the second experiments, since the higher-temperature air-flow was stoped, the outlet temperatures of the lower-temperature air were maintained at the constant temperatures for 90-150 minutes. In the third experiments, the higher-temperature air was flowed intermittently with an equal interval. The flow rates were equally 400 1/min, and the inlet temperatures of air were 70 C and 10 C, and the period was 2 hours. The outlet temperature of the lower-temperature air was between 20 C <plus-minus> 2.5 C. The above transient and periodical experiments showed that the present heat exchanger with PCM had useful characters of latent heat storagf