共查询到16条相似文献,搜索用时 187 毫秒
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设计了蒸发器盘管排列密度可以改变的直接蒸发冰盘管蓄冷装置,在高、中、低三种盘管排列密度情况下,进行了蓄冷槽内载冷剂在自然对流和强制对流下的静态和动态蓄冷实验,研究了盘管排列密度和蓄冷状态对蓄冷速率的影响。结果显示:高密度系统平均蓄冷速率较低密度系统提高27.9%以上,动态系统平均蓄冷速率较静态系统提高2%左右。 相似文献
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以竖直盘管直接蒸发内融冰式冰蓄冷空调蓄冰槽内的传热过程为基础,利用热阻网络法和能量平衡建立了融冰过程的数学模型,对其融冰机理进行了理论分析。计算结果表明,融冰过程中蓄冰槽盘管出口的制冷剂温度随时间逐渐升高,但在后期存在一个因冰柱碎裂上浮导致自然对流瞬时得到强化从而引起的短时间轻微下降现象。另外,蓄冰槽内的传热系数经历了先骤然降低,然后维持稳定,最后又快速上升的过程。该现象与盘管外由于冰融化所形成的水环直径有关,水环直径越大,释放冷量的速度就越小。通过与实验数据的对比,验证了计算模型的合理性和准确性。 相似文献
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新型气体水合物蓄冷装置及其性能 总被引:8,自引:0,他引:8
1前言蓄冷空调是调峰平谷,缓解电力紧张、提高供电效率的有效途径。目前应用较广的是冰蓄冷。在冰蓄冷系统中,由于蓄冷时制冷机组必须工作在制冰工况,使得机组电耗增加30~40%,同时系统中必须采用不冻液循环。气体水合物能克服这些缺点。气体水合物是水在一种外来气体(如制冷剂、天然气等)的作用下形成的笼状结晶物。这种结晶体可在8~12”C的温度下相变,正适合于空调的制冷温度,且其相变潜热与冰相当,是一种理想的空调蓄冷介质。目前国际上较佳的蓄冷系统是美国开发的Rll气体水合物蓄冷系统,蓄冷温度为8.5”C,实际蓄冷能力… 相似文献
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空调蓄冷材料研究现状及其新进展 总被引:4,自引:0,他引:4
分析了空调蓄冷材料研究现状及存在的一些问题 ,提出研制一种新型空调复合蓄冷材料 ,通过实验 ,分析该蓄冷材料的融点、融解热等热学性能。并通过实验研究寻找到了一种新型空调蓄冷材料 ,测试结果表明该蓄冷材料具有较高的相变潜热、适宜的相变温度和较好的热稳定性 ,因此可被应用于蓄冷空调系统中。 相似文献
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日蒸发率是评价高真空多层绝热杜瓦保冷性能最重要的技术参数。该文对日蒸发率的影响因素进行了总结,重点介绍了储存压力和环境温度对日蒸发率的影响。以充满率为90%的210L小型杜瓦为例,测试了日蒸发率的变化规律。结果表明,杜瓦的日蒸发率与储存压力成正比,同时日蒸发率的波动随着储存压力的升高而增大,且环境温度对日蒸发率的影响出现延迟。 相似文献
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Fedor Gmry Daniela Bettinelli Laura Gherardi Giovanni Crotti 《Physica C: Superconductivity and its Applications》1998,310(1-4):48-51
Magnetic nature of the losses in superconducting wire carrying AC current implies that it should be possible to determine these losses in a contactless way. Ribbon-like samples are quite favorable for such an experiment, because a notable portion of magnetic flux related to losses ‘escapes' the sample volume and can be detected by an appropriate pick-up coil. In this case, a model describing the AC current penetration into the tape, based, e.g., on the critical state model, allows one to derive the losses from the pick-up coil signal. Because this signal is proportional to the number of coil turns, extension of the accessible range of measured voltages (and losses) can be achieved. We demonstrate the data obtained on a 1 cm long portion of a low-loss multifilamentary tape carrying AC current with frequency 35 Hz. The pick-up coil technique allowed us to reach loss level more than one order below the experimental limit for direct measurements. 相似文献
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Zhao-Hui Li 《Applied Surface Science》2010,257(3):776-780
The laser direct patterning technique is one of the new methods of direct etching process to replace the conventional photolithography. In this experiment, a Q-switched diode-pumped Nd:YVO4 (λ = 1064 nm) laser was used to produce the indium-tin oxide (ITO) patterns with a complex T-shaped structure on glass substrate. The results showed that the overlapping rate of laser beam had a major effect on the quality of the edge of the ITO electrode. When the overlapping rate was about 75%, it was possible to obtain optimum linearity in the edge of patterned ITO electrode. By using the optimum conditions of 75% overlapping rate, 500 mm/s scanning speed, and 40 kHz repetition rate, an alternative current plasma display panels (AC PDPs) with T-shaped ITO electrode was fabricated and characterized. The discharging results showed that the AC PDPs with the laser ablated T-shaped ITO electrode had a better discharging characteristics compared to the conventional sample with wet-etched stripe-type ITO electrode. 相似文献
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重力场与静电场特点的比较 总被引:2,自引:1,他引:1
“场”是一种客观存在的物质,但由于“场”具有不易直接感受的特殊存在形态,同学们对“场”的物质性的理解不够深刻,解决“场”的相关问题时也感到棘手.笔者就高中阶段最典型的两种场——“重力场”和“静电场”的力学性质与能量特点进行比较,使同学们对“场”的概念有更深刻的认识. 相似文献