共查询到20条相似文献,搜索用时 167 毫秒
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为了提高空气调节效果,更有效地利用车间回风,介绍空气调节现状以及空调系统智能化改造后的运行效果;在对比人工控制和自动控制的实际耗电基础上,针对前期空调设计缺陷导致的车间回风量不足问题,再次改造细纱和后纺车间空调。结果表明:采用节能自动控制调节系统改造后,车间温湿度控制稳定可靠,有效降低了空调电耗;细纱和后纺车间4个空调室开启回风窗,进一步提高回风利用率,吨纱用电量降至3150 kW·h;在保证空调效果的前提下,停掉部分或者全部工艺排风和地排风风机,吨纱用电量可保持为3100 kW·h。 相似文献
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《烟草科技》2017,(2)
为解决卷烟厂空调系统能源消耗高等问题,根据卷烟厂热湿负荷特点,采用热水湿膜加湿和温湿度独立控制技术对空调系统进行了节能改造。通过设置新风湿度处理箱对湿度进行处理,采用新型湿膜加湿器进行加湿,采用小型表冷器进行除湿,处理后的新风与回风混合后经AHU(Air handling unit)空调箱温度调节送入车间,从而实现温湿度独立控制。结果表明:1空调热水湿膜的加湿能力和温湿度控制精度能够满足车间运行要求,最大温度差1.07℃,最大湿度差2.06%RH。2改造后空调系统蒸汽节能率50.56%,制冷节能率19.41%,年节省费用210.41万元。该技术有效解决了空调系统在全风量处理中出现的"冷热抵消"现象,满足了全年气候工况的运行要求,节能效果显著。 相似文献
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通过对夏季细纱车间空气调节设计,重点讨论了冷负荷、通风量、深井水量等的计算方法,并结合实践提出了温湿度控制要点。 相似文献
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本实验基于多孔介质热湿传递原理和粮粒吸湿/解吸湿理论,建立了通风过程中粮堆内部热湿耦合传递方程,采用数值预测的方法,研究了吨粮通风量不变、粮堆初始温度与通风空气温度差8℃情况下,粮堆初始平衡湿度与通风空气湿度差分别为-5%、0%和5%时,粮堆内部温度和水分随时间的变化规律。探究了通风湿度对稻谷横向保水降温通风过程中粮堆温度和水分的影响,分析了一定初始粮温和水分时通风空气温湿度对降温保水的效果,得到了稻谷横向降温保水通风的最佳湿度。研究结果可以丰富和完善横向降温保水通风工艺,同时也为横向降温保水通风的操作提供依据。 相似文献
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温湿度是影响粮食安全储存的重要因素,为保证储粮安全,采用机械通风,使粮堆和粮粒的温度和水分含量可以得到有效控制。该文基于多孔介质的传热传质理论,建立了仓储稻谷通风过程中粮堆内部流动和热湿耦合传递的数学模型以及粮粒的热量传递和水分输运模型。采用计算流体力学的方法,从粮堆尺度和粮粒尺度,分析了机械通风过程中仓储粮堆和粮粒内部的温度、水分分布规律。研究发现,通风过程阶段,粮堆内部温度降温显著,粮堆整体平均水分呈降低趋势,且粮堆内部温湿度受外界环境温湿度的影响很大;研究还发现粮粒水分扩散速度远小于温度扩散速度。研究结果可以为储粮横向通风保水降温的工作以及粮堆局部霉变、发热和害虫的发育的预防提供参考。 相似文献
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在广州市南沙区于2018年1月16日~2月7日期间,对装粮高度11 m的稻谷立筒仓(约650 t)采用自然冷空气进行智能化降温通风,分别采用5.5 kW和2.2 kW的离心风机上行式通风,风机运转条件是粮堆与大气温度之差≥3℃,粮堆平衡绝对湿度(EAHg)≦大气平衡绝对湿度(AHa)。结果表明,风机自动化运行时间主要在夜间,采用5.5 kW风机的301号仓粮堆平均温度由19.2℃降到13.8℃,风机运转了72.9h,单位能耗是0.087 kW·h t~(-1)℃~(-1);采用2.2 kW风机的501号仓粮堆平均温度由20.9℃降到12.4℃,风机运转了148.6 h,单位能耗是0.047 kW h t~(-1)℃~(-1),与当地人工控制的吸出式下行降温通风单位能耗比较,显著节约电能54%~75%。两个智能化降温通风仓通风结束后粮堆水分保持不变。与对照仓比较,采用低功率离心风机进行智能化降温通风后的稻谷出米率和加工品质有提高的趋势。这说明稻谷立筒仓智能化通风期间整个粮堆湿热分布均匀,不发生水分迁移。 相似文献
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A.P. Louie J.D. Rowe W.J. Love T.W. Lehenbauer S.S. Aly 《Journal of dairy science》2018,101(11):10230-10247
Heat stress has the potential to adversely affect the physiology, passive immunity, and growth of preweaning dairy calves, increasing their risk of respiratory disease. The effect of heat stress on the risk for bovine respiratory disease (BRD) may be mediated in part through housing, ventilation, and management factors. As a result, differences may exist in meteorological measures recorded in the calf-rearing area (macroenvironment) and within a calf's enclosure (microenvironment). The objective of this prospective cohort study was to evaluate and compare the association between exposure to temperature and humidity measured at the macro- and microenvironment, and BRD in preweaning dairy calves; a secondary objective was to evaluate the correlation between the macro- and microenvironment. A cohort of 252 calves from 4 premises in central San Joaquin Valley, California (CA), was followed and evaluated for development of respiratory disease using the CA BRD scoring system for preweaning dairy calves, a standardized and validated scoring system. During this time, the meteorological conditions of the calf-rearing area and the within-hutch environment were measured and showed a significant correlation with regard to temperature and humidity. Mixed effects logistic regression and survival analysis were used to analyze the association between the exposures daily environmental measures of temperature, humidity, and temperature-humidity index (THI) and the outcome BRD, adjusted for dairy premises, calf age, sex, and breed. Results showed a significant positive association between daily maximum temperature and BRD in both the calf's macroenvironment [odds ratio = 1.121 (95% confidence interval (CI) = 1.029–1.222)] and microenvironment [odds ratio = 1.203 (95% CI = 1.020–1.418)]. Estimated hazard rates also showed a significant positive association between BRD and daily maximum temperature in both the macroenvironment [hazard ratio = 1.127 (95% CI = 1.053–1.206)] and microenvironment [hazard ratio = 1.119 (95% CI = 1.047–1.197)]. In contrast, we found no association between daily maximum humidity in a calf's microenvironment and BRD. Daily maximum THI within the hutch was significantly associated with only the rate of BRD cases [hazard ratio = 1.070 (95% CI = 1.003–1,141)] but not the odds of occurrence of BRD. Maximum THI is estimated using temperature and humidity, which in California's hot and dry summers may limit variability in THI, explaining its weaker significant association with risk of BRD (or lack of association with odds of BRD) compared with models for maximum temperature in this study. Calves exposed to high day temperatures and relatively low humidity may be experiencing heat stress that predisposes to BRD. Results of the current study suggest that heat abatement efforts should address heat stress at the microenvironment level to mitigate BRD in calves. Further research should investigate strategies to improve calf hutch systems, including hutch materials and design that may optimize ventilation, provide ample shade, spacing, cleanliness, and protection from heat. 相似文献