共查询到18条相似文献,搜索用时 828 毫秒
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作者阐述了在热网设计中,R值的选取直接影响到管网的投资,也影响到热网的运行费用。本文分析了热网设计中R值选取时应考虑到的各种因素,并提出选取办法对热网设计有一定的参考价值。 相似文献
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建筑物蒸汽及凝结水回收系统主要应用于集中供热的蒸汽热网的各建筑物分支,用于供暖,卫生热水,蒸汽型溴化锂冷水机组,厨房及洗衣房等用汽场所。本文介绍了该系统的工作原理,设计参数的选择,系统的构成及施工,使用中需注意的问题。 相似文献
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根据大学体育馆使用的特殊性,提出大学体育馆空调通风系统自监控的设计思想、原则、监控内容和目标,并选择合适的监控系统,采取适当的节能措施,进行空调通风系统监控设计,这里介绍了建筑设备监控系统、系统的构成、本监控系统采取的节能措施。 相似文献
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城市采暖供回水温度的选择 总被引:1,自引:1,他引:0
热网供回水温度是影响机组经济运行的主要因素,其供回水温度的合理选取直接影响到项目的经济性。本文对热网供回水温度选取进行了分析论述,以求得合理的参数,更好的进行设备选型。 相似文献
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对珊瑚树离体叶片光合,蒸腾特性研究结果表明,珊瑚树叶片离体的短时间内(2h),在供水情况下,一年生叶净光合速率有一定程度的下降,二年生叶则几乎没有下降,两种叶片蒸腾速率基本不变,而不供水叶片净光合速率和蒸腾速率为化很大。在低温,黑暗,供水条件下,可延长离体叶片生理活性的保存时间,但至12h,各种光合参数发生了较大的变化。 相似文献
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Four full-sib families of interior spruce (Picea glauca (Moench) Voss) x Picea engelmanii Parry ex Engelm.) with contrasting growth rates (two fast-growing and two slow-growing families) were grown aeroponically with either a 2% relative nitrogen addition rate or free access to nitrogen. Fast-growing families showed greater plasticity in allocating biomass to shoots at high nitrogen supply and to roots at low nitrogen supply than slow-growing families. Compared with the slow-growing families, short-term net ammonium uptake rate measured with an ion selective electrode was significantly greater in fast-growing families at high ammonium supply, but not at low supply. Net nitrate uptake showed the same trend, but differences among families were not significant. Results indicate that differences in seedling growth rate are partly a result of physiological differences in net nitrogen uptake efficiency and nitrogen productivity. 相似文献
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变频调速给水装置,它采用交流变频调速技术,是集机械、电气、微机控制于一体的高科技节 能产品,可以满足恒压变量的需求,供水管网未端保持恒压,使供水系统始终处于高效节能的最佳状态。 相似文献
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Temperature-independent fluctuations in stem CO(2) efflux were measured in Pinus taeda L. seedlings. Stem CO(2) efflux was measured during high and low transpiration rates, high and low net photosynthesis rates, and normal and interrupted substrate supply conditions. Stem CO(2) efflux rates were an average of 6.7% lower during periods of high transpiration compared to periods of low transpiration. This difference in stem CO(2) efflux rates was not due to water stress. The most likely cause was movement of respiratory CO(2) in the transpiration stream. Interruption of substrate supply to the stem by phloem girdling reduced stem CO(2) efflux rates. Increasing net photosynthesis rates from low to high had no effect on stem CO(2) efflux, but decreasing net photosynthesis from high to low caused relatively small reductions in stem CO(2) efflux. These results indicate that diurnal changes in net photosynthesis rate may play a small role in temperature-independent afternoon depressions of stem CO(2) efflux. The transport of respiratory CO(2) by the transpiration stream compromises measurements of woody tissue respiration obtained by commonly accepted gas exchange techniques. This phenomenon could also affect measurement of leaf net photosynthesis and branch woody tissue respiration. 相似文献
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对多级泵形式的供热管网的压力工况做出了分析,基于对不同的多级泵布置方式的循环动力能耗计算,得出了多级泵布置中的一些注意事项。 相似文献