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对螺杆式冷水机组有关问题的讨论 总被引:1,自引:0,他引:1
对螺杆式冷水机组设计选型中常遇到的螺杆形线及齿数、开启式与封闭式、单螺杆与双螺杆、能量调节方法、带与不带节能器、干式蒸发器与满液式蒸发器、热力膨胀阀与电子膨胀阀等问题进行了分析,提出了一些看法。 相似文献
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水冷式冷水机组选型分析 总被引:3,自引:0,他引:3
水冷式离心、螺杆和活塞式冷水机组以其各自鲜明的特点,优良的性能而在大、中和小冷量范围内得到广泛的应用。本文分别对水冷式离心、螺杆和活塞冷水机组所使用不同制冷剂、不同工况和不同污垢系数进行了理论分析和实际性能对比,给出其对水冷离心式、螺杆式和活塞式冷水机组性能影响的大小,为实际选型和使用打下基础。 相似文献
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通过对所使用制冷剂、名义工况和污垢系数的理论分析和实际性能对比,给出其对离心式冷水机组性能影响大小,为实际选型和使用打下基础。 相似文献
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介绍了冷水机组COP现场测量的方法,通过实例对冷水机组COP测量进行了不确定度的评定,分析了COP测量不确定度的主要来源以及各测量参数对COP测量结果的影响程度。 相似文献
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分析了污垢对管壳式换热器的热动力性能及换热器设计计算的影响,讨论了污垢热阻估算方法和流体流动方式的选择。 相似文献
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Broens F Menne D Pothof I Blankert B Roesink HD Futselaar H Lammertink RG Wessling M 《Water research》2012,46(4):1113-1120
Today’s ultrafiltration processes use permeate flow reversal to remove fouling deposits on the feed side of ultrafiltration membranes. We report an as effective method: the opening and rapid closing of a valve on the permeate side of an ultrafiltration module. The sudden valve closure generates pressure fluctuations due to fluid inertia and is commonly known as “water hammer”. Surface water was filtrated in hollow fiber ultrafiltration membranes with a small (5%) crossflow. Filtration experiments above sustainable flux levels (>125 l (m2h)−1) show that a periodic closure of a valve on the permeate side improves filtration performance as a consequence of reduced fouling. It was shown that this effect depends on flux and actuation frequency of the valve. The time period that the valve was closed proved to have no effect on filtration performance. The pressure fluctuations generated by the sudden stop in fluid motion due to the valve closure are responsible for the effect of fouling reduction. High frequency recording of the dynamic pressure evolution shows water hammer related pressure fluctuations to occur in the order of 0.1 bar. The pressure fluctuations were higher at higher fluxes (higher velocities) which is in agreement with the theory. They were also more effective at higher fluxes with respect to fouling mitigation. 相似文献
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建立水源热泵机组数学模型,进行部分负荷下冷冻水侧变流量对机组性能影响模拟。结果表明:变流量时流量变化范围并不与机组负荷变化成线性关系;无论定、变流量,部分负荷下冷凝温度下降,蒸发温度升高,机组COP随着负荷减小先增大后减小;在一定范围内冷冻水变流量对机组本身性能影响并不显著,却会使冷冻水泵功耗有较大幅度下降。 相似文献
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本文旨在说明大型商住综合楼集中热水系统热源选用宅调冷水主机热回收热水设备与风冷式热泵热水机的组合,是经济合理的热源配置方式。 相似文献
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Fouling in membrane coupled photocatalytic reactors was investigated in the case of greywater treatment by establishing the link between product type, dose, irradiation time and fouling rates in a cross flow membrane cell fitted with a 0.4 μm pore sized polyethylene membrane. Rapid fouling occurred only with shower gels and conditioners and was linked to changes in the organo-TiO2 aggregate size postulated to be caused by polymers within the products. Fouling was reduced to a negligible level when sufficient irradiation was applied demonstrating that the membrane component of the process is not the issue and that scale up and implementation of the process relates to effective design of the UV reactor. 相似文献