共查询到20条相似文献,搜索用时 46 毫秒
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1 引言温室内生产的蔬菜和花卉等作物 ,产量高 ,质量好 ,无污染。因此 ,它是现代化农业的重要标志。几年前 ,上海、北京等地已引进了荷兰、以色列、美国、法国等国外的温室 ,经过一段时间的运行 ,总体上还是比较成功的 ,积累了很多经验。然而 ,引进的温室存在如下的问题 :(1)温室的造价较贵 ,使得温室蔬菜作为商品的成本过高而无法进入普通百姓的家庭。(2 )温室的构造和配套的技术设备没有全面考虑我国的气象特点 ,而是基本照搬了国外技术 ,导致温室的年利用率降低。上海孙桥现代农业开发区与同济大学联手 ,在吸收和消化国外温室产品的基础… 相似文献
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单斜面温室是我国北方农村一种高效益、低成本、具有显著经济效益的生产设施。文章研究了单斜面温室在冬季或早春季节里的供暖问题,通过理论计算,给出了一种确定所需换热器数量的方法。 相似文献
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本文从连栋温室供热系统的节能要求出发,重点研究了常用的热水供热系统光管散热管道的热工性能在涂辐射涂层前后性能变化,及提高散热管道辐射换热特性对温室内热环境的影响,为设计经济合理的连栋温室提供依据。 相似文献
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Greenhouse gas emission savings of ground source heat pump systems in Europe: A review 总被引:2,自引:0,他引:2
Peter Bayer Dominik SanerStephan Bolay Ladislaus RybachPhilipp Blum 《Renewable & Sustainable Energy Reviews》2012,16(2):1256-1267
An overview is presented on the last decade of geothermal heating by ground source heat pumps (GSHPs) in Europe. Significant growth rates can be observed and today's total number of GSHP systems is above 1 million, with an estimate of about 1.25 million mainly used for residential space heating in 2011. These systems are counted among renewable energy technologies, though heat pump operation typically consumes electricity and thus only a fraction of the energy produced is actually greenhouse gas (GHG) emission free. Consequently, only in the most mature markets of the Scandinavian countries and in Switzerland, calculated emission savings reach more than 1% compared to standard heatings. However, Sweden shows that more than 35% is possible, with about one third of these systems in Europe concentrated in this country. Our calculations demonstrate the crucial role of country-specific heating practices, substituted heat mix and primary electricity mix for country-specific emission savings. For the nineteen European countries studied in 2008, 3.7 Mio t CO2 (eq.) are saved in comparison to conventional practice, which means about 0.74% on average. This reveals that many countries are at an early stage with great potential for the future, but even if the markets would be fully saturated, this average would barely climb to about 30%. These numbers, however, take the current conditions as reference, and when extrapolated to the future can be expected to improve by greener electricity production and increased heat pump performance. 相似文献
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地板辐射采暖是一种舒适、环保、节能的现代供暖方式。在诸多供暖技术中,地板辐射供暖技术无疑是热舒适度最好的一种供暖方式。在设计中,不但要对地面构造、热媒、热管系统及分集水器进行合理的设计,还要分别对负荷、散热量和热管水力进行系统的计算,同时加以正确的选材与施工才能充分发挥出地板辐射供暖的技术的优势。 相似文献
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G6135受热负荷零件的温度场测试研究 总被引:4,自引:0,他引:4
过文卿 《柴油机设计与制造》2001,(3):44-47
上海柴油机股份有限公司生产的G6135柴油机在试验考核中,出现第五、六缸拉缸现象。为探究原因,测试人员自行设计,改装设备,运用硬度塞法和热电偶法分别对G6135柴油机活塞和缸套进行温度场测试,这进一步优化和改进零部件设计提供依据。 相似文献
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本文介绍了变频调速器在风机中的具体应用,给出了变频调速在锅炉及加热炉燃烧控制过程中的应用实例,阐明了变频调速的原理。 相似文献
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