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为完善适用于我国严寒地区居住建筑气密性与室内热舒适之间的关系,以沈阳市某小区一户住宅为模拟对象,对严寒地区居住建筑气密性与室内热舒适之间的关系进行探究.模拟分为冬季工况、夏季工况和过渡季工况,针对住宅内南北侧典型房间室内热舒适随气密性等级不同的变化情况进行模拟分析.研究发现,不同季节条件下,室内热舒适度随气密性变化情况... 相似文献
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变频式户式空调的应用探讨 总被引:5,自引:0,他引:5
节能一直是暖通空调的热门话题。近年来,随着人们生活水平的提高,居住环境有了很大的改善,人们对住宅建筑提出了更高的舒适性要求,家用空调市场空前火爆起来,面对如此巨大的家用空调消费群体,本文从节能的角度出发,指出了变频式户式空调方式是一种值得推荐的住宅空调方式。 相似文献
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为探究住宅建筑中装修板材承载率及通风方式对室内甲醛质量浓度的影响,采用EnergyPlus软件建立上海地区典型住宅计算模型,进行室内全年甲醛质量浓度模拟。根据上海地区全年室内甲醛质量浓度的实测数据验证模拟结果的准确性,并采用该模型在3种通风方式(渗透通风、自然通风、机械通风)下检验现行标准中承载率限值及计算方法的可靠性。结果表明,按照现行标准中的板材承载率限值进行装修,在3种通风工况下,上海地区典型住宅室内甲醛质量浓度超标率分别为14.37%~18.30%、8.36%~14.93%、1.92%~7.63%。自然通风和机械通风均能改善超标情况,其中机械通风的改善效果更明显。因此,亟需修正现行标准中板材承载率限值及计算方法,以便更加准确地指导上海地区住宅室内装修。 相似文献
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以满足新的节能设计标准的住宅楼内的44户住户为研究对象,基于住宅采暖耗热量和用电量的数据采集和统计分析,掌握新建住宅楼在实际使用过程中的采暖、空调以及生活用电能耗状况,研究分析住宅建筑的能耗结构。结果表明新建住宅建筑的采暖能耗远未达到、节能标准的要求,其次生活用电的能耗也很大。进一步的问卷调查、测试、模拟计算以及对比分析表明,导致住宅高能耗的主要原因在于居住者不合理的采暖、空调和生活用电行为。因此,在住宅节能的研究工作中,应对建筑中的人行为状况予以足够的重视。 相似文献
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由上海地区住宅冬季夜间卧室门窗关闭时CO_2体积分数现场检测结果得到卧室夜间渗透风换气次数,根据检测住宅的问卷调查结果,运用统计学中相关分析和多元回归分析方法,宏观分析住宅特性与冬季夜间卧室渗透风换气次数的相关性。研究结果表明:所检测的上海地区冬季夜间卧室渗透风换气次数在0.07~0.88 h~(-1)之间,多数住宅仅靠渗透风量不能满足最小新风量的要求。按影响强弱排序,窗户类型、门窗缝隙长度、住宅类型均与渗透风换气次数有显著相关性;利用现场实测的25个住宅实测样本建立预测上海地区冬季夜间卧室渗透风换气次数的多元线性回归模型,其渗透风换气次数预测值与计算值平均绝对百分误差为26.7%,标准差为0.025 h~(-1)。利用未参与建模的5个实测样本对模型进行验证,模型预测值与计算值的相对误差在-20.4%~24.2%。所建模型可为上海地区住宅冬季夜间卧室渗透风换气次数快速评估及建筑能耗预测提供参考。 相似文献
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上海市集合住宅气密性能实测及换气性能分析 总被引:5,自引:0,他引:5
对上海 13户居民住宅气密性能进行了实测调查 ,结果表明近年来随着建筑技术的发展 ,住宅的气密性能有了较大的提高。根据简易算法对住宅的自然通风量进行了预测 ,换气量根本无法达到相关的标准规定。如何采取主动式的通风措施来改善室内的空气环境已经是一个突出的问题 相似文献
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Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden. 相似文献
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《热能动力工程》2014,(5)
正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%. 相似文献
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The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°, −5°, +5°, +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods. 相似文献
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A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified. 相似文献
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As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied. 相似文献
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The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σred = σ1 β + (1 − β)σi, where: σ1-maximal principal stress, σi-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures. 相似文献
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Jaime Massanet-Nicolau Alan Guwy Richard Dinsdale Giuliano Premier Sandra Esteves 《International Journal of Hydrogen Energy》2010
Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H2 kg−1 VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min−1 successfully prevented a decline in hydrogen production and resulted in a yield of 27.0 L H2 kg−1 VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production. 相似文献