Research on Energy-Saving Performance of Intermittent Heating for Rooms in Hot Summer&ColdWinter Zone

In the hot summer&cold winter zone in China,intermittent heating space for rooms is widely used.However,in comparison with continuous space heating,the energy-saving performance of intermittent space heating has not been sufficiently investigated.This paper studied the factors influencing the energy performance of intermittent heating for the representativeoffice inhot summer&coldwinter zone.Basedon theheatbalancemethod,adynamic thermalmodel of the intermittent heating roomwas built and tested by experiments.And then,it analyzed the total space heating load,the amount of energy saving and energy saving ratio of the intermittent heating under different preheating hours,occupation hours,required roomtemperatures,air change rates,overall heat transfer coefficients(U-value)of windows and wall materials.If the adjacent rooms were not heated,for a typical room occupied about 10 h a day,the energy-saving ratio of intermittent heating was about 30%compared with continuous heating.But the preheating power was higher than two times of continuous heating.The results also indicated that the occupation hours had a significant effect on energy saving amount and ratio,it should be noted that the energy saving ratio by intermittent heating was much lower than the unoccupied period ratio.Relative to other factors,the heating temperatures,room air change rates and U-value of windows,and room envelope materials had little effect on energy efficiency.If the adjacent rooms were heated in the same manner as the roomin question,the energy-saving ratio of the total load of intermittent heating was heavily reduced to 8.46%.

Analysis on Scale, Level and Structure of China-Kazakhstan Intra-Industry Trade of Energy Products-Based on Silk. Road Economic Zone as Strategic Background

论文依次从规模、水平、结构三个角度,分析1999年-2014年中国与哈萨克斯坦能源产品产业内贸易发展状况D 结果表明：中哈能源产品贸易规模扩大,但以产业间贸易为主,产业内贸易集中于石油产品,其中垂直型产业内贸易占主要地位,能源产品产业内贸易有较大提升空间D 在此基础上对中哈能源产品产业内贸易影响因素进行探究,考察经济规模、收入差异、贸易公平程度、外商直接投资等四个因素对产业内贸易的影响,为发展中哈能源贸易提供实证依据及合理建议.

Vibration analysis of steel structures including the effect of panel zone flexibility based on the energy method

New approximate formulas are proposed to determine the natural frequencies of structures considering the effects of panel zone flexibility and soil-structure interaction. Several structures with various earthquake resisting systems are idealized as prismatic cantilever flexural-shear beams. Floor masses are considered as lumped masses at each story level and masses of columns are evenly distributed along the cantilever beam. Soil-structure interaction is considered as axial and rotational springs, whose potential energy are formulated and incorporated into overall potential energy of the structure. Subsequently, natural frequency equations are derived on the basis of energy conservation principle. The effect of axial forces on natural frequency is also considered in the proposed formulas. Using the method presented in this study, natural frequencies are computed using a simplified method with no complex numerical modeling. The proposed formulas are verified via experimental and numerical methods. Close agreement between the results from these three approaches are observed. Furthermore, the effects of panel zone flexibility, continuity plates and doubler plates on the natural frequencies of buildings are investigated.

Comparative study of surface energy and land-surface parameters in different climate zones in Northwest China

Based on observational data of arid,semi-arid and semi-humid areas in Northwest China,the characteristics of surface-wa ter heat transfer and land-surface parameters were compared and analyzed.The results show that the annual mean net radi ation was largest in the semi-humid area,followed by the semi-arid area,and then the arid area:77.72 W/m^2,67.73 W/m^2,and 55.47 W/m^2,respectively.The annual mean sensible heat flux was largest in the arid area,followed by the semi-arid and semi-humid areas,while latent heat flux showed the reverse.The annual mean sensible heat flux in arid,semi-arid,and semi-humid areas was 85.7 W/m^2,37.59 W/m^2,and 27.55 W/m^2,respectively.The annual mean latent heat flux was 0 W/m^2,26.08 W/m^2,and 51.19 W/m2,respectively.The annual mean soil-heat flux at the 5-cm soil layer in arid,semi-arid,and semi-humid areas was 1.00 W/m^2,0.82 W/m^2,and 1.25 W/m^2,respectively.The annual mean surface albedo was larg est in the arid area,followed by the semi-humid area;and the smallest was in the semi-arid area:0.24,0.21,and 0.18,re spectively.The annual mean Bowen ratio in the semi-arid area was about 2.06,and that in semi-humid area was about 0.03.The annual mean soil thermal conductivity in the arid,semi-arid,and semi-humid areas was 0.26 W/(m k),1.15 W/(m k),and 1.20 W/(m k),respectively.

Assessment of Wind Energy Potential in the Sudanese Zone in Chad

In this study, wind characteristics and wind power potential are analyzed for three meteorological stations in the Sudanese zone of Chad for the period of 35 years (from 1975 to 2010). Assessment of the wind power potential was carried out using the two parameters of Weibull distribution. Results of the study shows that the average annual wind speeds at 10 m above ground for Moundou, Pala and Sarh are 2.69, 2.33 and 1.91 m/s, respectively. The mean annual value of the Weibull shape parameter k and scale parameter c range from 2.376 to 3.255 and 2.099 to 3.007, respectively. The maximum annual power density of 204.85 W/m2 was obtained at Moundou. Results of this study further shows that the selected locations are not suitable for large-scale wind energy production at 10 m altitude. However, by extrapolation, assessment of wind speed at 67 m altitude combines with wind turbine Vestas 2 MW/80 that adapts to the Sudanese local conditions, and the wind power potential can be exploited for water pumping, heating and production of electricity.

Study of Dissipating of Wave Energy in the Breakers Zone of the Gulf of Guinea: Case of Autonomous Port of Cotonou in Benin Coastal Zone

Rapid population growth and major trends of world economy growth have led to significant energy needs in our country. Benin, Gulf of Guinea country, although with a significant coastal network powered by potential energy from breaking waves, has experienced a deficit and a critical energy instability, marked by recurrent power cuts and disruption of the national economy. To ensure the integration of this source of renewable energy in the Benin energy mix and sustainably reduce the energy deficit in progress, this work has aimed to study the dissipation of wave energy at the bathymetric breaking in the breakers zone of Cotonou coast. Sea conditions and the statistics parameters of the breaking waves under perturbation effect of the seabed were evaluated to predict the beginning of the breaking. The modeling is based on the Navier-Stokes equation in which the viscosity and the interactions between the molecules of the oceanic fluid are neglected. The nonlinear wave dispersion relation is also used. The results obtained for this purpose showed that water particles have an almost parabolic motion during their fall;their velocity is higher than those of the early breaking. In this area, the waves dissipate about 80% of their energy: it generates turbulence which leads to a strong setting in motion of sediments.

A Novel Energy Lifting Approach Using J-Function and Flow Zone Indicator for Oil Fields

The X field is located in the southwestern part of block NX89 of Kentan Basin in Libya.This field is produced from Hailan multilayer consolidated sandstone with moderate rock property and a relatively low energy supplying.The reserve of subsurface energy sources is declining with years.Therefore,techniques were combined to achieve the energy optimization and increase hydrocarbon recovery.In order to understand the subsurface formation of the reservoir and facilitate oil production,global hydraulic element technique was used to quantify the reservoir rock types.In addition,stratigraphic modified Lorenz plot was used for reservoir layering.Reservoir heterogeneity was identified using stratigraphic modified Lorenz plot and Dykstra-Parsons coefficient.Leverett J-functionwas used to average the 13 capillary pressure curves into four main curves to represent the whole reservoir based on flow zone indicator values.Capillary pressure was calculated and plotted with normalized water saturation;a single average curve was defined to represent the rest of the curves.Water saturation was calculated using single and multiple J-functions and compared with the available logs.With multiple J-functions,the matching results were good for both high and low-quality layers,whereas using a single J-function,the match was poor,especially for low FZI layers such as H4c and H6a.Four rock types were identified for this reservoir ranging from medium to good reservoir quality and six different layers were obtained.The reservoir was heterogeneous with a Lorenz coefficient value of approximately 0.72 and a Dykstra-Parsons value of 0.70.All approaches used in this paper were validated and showed improved hydrocarbon recovery factor.

The Study on the Relationship between Dynamic Balance Energy Distribution and Spectral Stability with Voltage Change in White Organic Light Emitting Diode

The stable spectrum can be obtained when the voltage changes, which is a necessary condition for the white organic light emitting diode (WOLED) device to be widely used in the field of solid-state lighting. However, with the increase of voltage, the movement of the recombination zone (RZ) is inevitable because the perfect bipolar host material is difficult to obtain, which will redistribute the energy in the light emitting layer (EML) and affect the stability of the spectrum. We fabricate a series of ternary hybrid WOLEDs with a simple structure by inserting ultra-thin PO-T2T into the blue exciplex (TCTA:TPBi) to form the green interface exciplex. Without considering the movement of RZ, device B2 realizes the dynamic balance energy distribution in EML and stable spectrum by controlling two processes of the Dexter energy transfer and exciton capture. By modifying the doping ratio of the host material, we also find that the broadened RZ is helpful to further improve the spectral stability of the device. When the voltage changes from 3 V to 7 V, the change range of color coordinates is only (0.026, 0.025).

Variation of the Energy Field of Longmenshan Fault Zone before the Wenchuan M_S 8. 0 Earthquake

During the process of preparation and occurrence of a large earthquake,the stress-strain state along the fault zone has close relation with the weak seismicity around the fault zone. The seismic energy release near the fault zone before an earthquake can better reflect the dynamic process of earthquake preparation. Thus,in this paper,the method of natural orthogonal function expansion has been adopted to discuss the time variation about the energy field of the seismic activity along the Longmenshan fault zone before the Wenchuan M_S 8. 0 earthquake,2008. The results show that evident short-term rise changes appeared in the time factors of the typical field corresponding to several key eigenvalues of the energy field along the Longmenshan fault zone before the Wenchuan earthquake,probably being the short-term anomaly message for this earthquake. Through contrastive analysis of earthquake examples such as the 1976 Tangshan earthquake,the authors think that the study of time variation of energy field of seismicity along active fault zone will be helpful for conducting intentional and intensive earthquake monitoring and forecast in active fault regions with high seismic risk based on medium- and long-term earthquake trend judgment.

全球天然氢气勘探开发利用进展及中国的勘探前景

在全球能源脱碳背景下,天然氢气作为一种一次能源,因其零碳、可再生的优点而备受关注,但中国目前还未开展专门针对天然氢气的勘探工作。通过介绍全球已知高含量天然氢气(体积分数大于10%)气藏的主要形成地质环境及成因类型,系统总结了天然氢气富集的有利地质条件,并结合国外天然氢气的勘探开发现状,评价了中国天然氢气的勘探前景。研究结果表明:(1)全球高含量天然氢气主要发育于蛇绿岩带、裂谷和前寒武系富铁地层中,且以无机成因为主,富铁矿物的蛇纹石化过程是天然氢气最主要的成因来源,其次为地球深部脱气和水的辐解。(2)优质的氢源与良好的运移通道是氢气富集的前提,而盖层的封盖能力是天然氢气能否成藏的关键要素;天然氢气作为伴生气时,传统盖层对其具备封盖能力,但当其含量较高时,传统盖层可能难以形成有效封盖;裂谷环境、蛇绿岩发育区以及断裂发育的前寒武系富铁地层是富氢气藏的勘探有利区。(3)国外多个国家和地区已制定了天然氢气的勘探开发和利用计划,其中,马里已实现天然氢气的商业开采,美国、澳大利亚也已成功钻探天然氢气勘探井。(4)中国高含量氢气区与富氢地质条件高度匹配,天然氢气勘探前景良好,郯庐断裂带及周缘裂陷盆地区、阿尔金断裂带及两侧盆地区、三江构造带—龙门山断裂带及周缘盆地区的天然氢气勘探潜力较大;中国应尽快开展天然氢气普查工作,加强氢气成藏过程研究和潜力评价,并进行勘探技术、开采分离技术和储运技术的攻关,为天然氢气的大规模开发利用做好技术储备。

大庆喇嘛甸油田低碳示范区建设探索与实践

“双碳”背景下,大庆油田全力构建清洁高效的能源体系,打造千万千瓦级新能源基地。喇嘛甸油田结合特高含水开发及整装油田典型特点,依托资源优势,探索建设喇北北块低碳示范区。以全面能源调查为基础,明确将灰电与天然气作为替代目标,确定了“节能降碳、清洁替碳”两步走建设思路。结合油田用热特点,整体部署油田余热、地热、光热及电热多能互补方案,全面实施工艺流程再造、立体化节能、清洁热能替代、清洁电能替代。根据油田中部地区管网密度大、周边可利用土地多的特点,以最大发电量、最小弃电量为目标,整体优化风光发电建设布局和规模,以实现区域多能互补、供用能平衡及高替代率。低碳示范区将新能源技术与现有生产工艺深化融合,开展了先导性的储能、制氢、微电网、能源管控技术研究。低碳示范区预期2025年全面建成,清洁能源替代率将达到46.4%,将有力推动油田能源变革、绿色低碳转型。

基于内聚力模型的再生沥青混合料低温断裂性能研究

内聚力模型(CZM)在沥青混凝土开裂研究中得到了广泛应用,但采用内聚力模型对再生沥青混凝土断裂的研究还很少。本文采用随机算法和坐标控制法建立包含旧集料和新集料的再生沥青混合料半圆弯拉模型,将模型分为集料同分布模型和集料随机分布模型两类。研究-10℃时不同RAP掺量(0、25%、50%、75%、100%,质量分数)对再生沥青混合料SCB试件应力强度因子K_(IC)、断裂能G_(F)和抗裂指数I_(CR)的影响。研究结果表明:无RAP掺入的SCB试件具有较好的断裂性能;随着RAP掺量增大,应力强度因子K_(IC)、断裂能G_(F)和抗裂指数I_(CR)均减小,表明RAP的掺入会削弱沥青混合料的低温断裂性能;采用有限元模型得到的断裂参数与室内试验结果一致;相比于集料同分布模型,集料随机分布模型各评价指标的变异性系数整体更大,表明集料分布状态对开裂结果有一定影响;当计算样本足够多时,这两类模型获得的抗裂参数变化规律一致,可有效评价再生沥青混合料断裂性能。

夏热冬冷地区居住建筑辐射型反射隔热涂料节能设计方法研究

辐射型反射隔热涂料在夏热冬冷地区居住建筑中的应用案例越来越多,其节能设计方法备受关注。等效热阻法是目前反射隔热涂料热工设计的标准方法,但相关文献研究指出,涂覆于非透明材料上的隔热涂料应采用太阳光直接反射比作为隔热评价指标,不宜用等效热阻来评价。通过上海某6层住宅建筑探讨了夏热冬冷地区居住建筑外墙采用辐射型反射隔热涂料的节能效果及其传热系数、太阳辐射吸收系数和表面发射率之间的关系,对比分析了采用参数直接计算与等效热阻法计算能耗结果,结果表明:1)辐射型反射隔热涂料隔热机理与反射隔热涂料差异明显;2)辐射型反射隔热涂料节能效果不适宜采用等效热阻法进行节能效果评价;3)辐射型反射隔热涂料墙体冬季保温热阻设计应充分考虑其对墙体温度的负面影响。

新能源汽车产业集聚对区域绿色经济效率的影响——基于长江经济带的实证研究

将产业集聚、绿色技术创新和绿色经济效率纳入同一研究框架,聚焦长江经济带,研究新能源汽车产业集聚对绿色经济效率的影响,为我国在“双碳”背景下推进实现制造强国的战略目标及长江经济带新能源汽车发展提供参考。论文基于2012—2020年长江经济带沿线11个省市面板数据,综合利用超效率SBM和区位熵法,构建计量模型,实证研究新能源汽车产业集聚对绿色经济效率的影响,探讨绿色技术创新的中介效应,并进一步分析新能源汽车产业集聚对绿色经济效率的空间溢出效应和区域异质性。研究结果表明:1)长江经济带整个区域已形成“带状”新能源汽车产业集聚区,集聚平均水平随年份波动上升,上中下游产业集聚水平呈递增格局,水平差异较大且有逐渐增加趋势;2)新能源汽车产业集聚通过整合内部网络资源和提升外部整体能力,对长江经济带绿色经济效率具有正向促进作用;3)产业集聚的发展通过竞争效应和合作效应促进绿色技术创新,而绿色技术创新的发展可以提升经济动力和效率,因而绿色技术创新在产业集聚与绿色经济效率之间具有中介作用;4)新能源汽车产业集聚对绿色经济效率具有空间溢出效应,上中下游新能源汽车产业集聚对绿色经济效率的影响存在差异。据此,从加强产业集群建设,发挥新能源汽车产业发展的长效机制、强化发展绿色技术创新体系和推动新能源汽车区域异质性发展三个方面提出对策建议。

基于个人舒适系统杭州住宅冬季热舒适与能耗

为揭示该地区个人舒适系统(PCS)作用下的居民冬季热舒适特征和供暖能耗需求,以杭州市为对象,采用问卷调研和入户现场实测的方式得出冬季住宅开窗、遮阳、使用空调和PCS等典型热环境组合调节模式以及典型供暖模式和居民活动状态组合下的热舒适特征;在此基础上模拟得到冬季室内热舒适和供暖能耗特征。结果表明,冬季“无设备+静坐”、“空调+静坐”、“PCS+静坐”、“无设备+家务劳动”、“空调+家务劳动”、“PCS+家务劳动”等6种工况下的冬季中性温度分别是17.3、18.8、16.4、15.7、15.7、13.9℃,舒适温度区间分别是14.3~20.3℃、17.1~20.5℃、14.4~18.4℃、13.7~17.8℃、13.3~18.1℃、11.0~16.9℃。冬季室内热舒适水平受热环境调节模式影响较大,客厅在室舒适时间占比在43.74%~80.21%之间,卧室在室舒适时间占比均为70%以上。使用空调与PCS供暖时,典型建筑在冬初冬末的供暖能耗强度是1.28 kWh·m^(-2),在严冬的供暖能耗强度是13.06 kWh·m^(-2)。

基于变分模态分解的采空区“三带”微震信号能量衰减规律

为探明微震信号能量在采空区“三带”结构中的衰减规律,拟开展采空区覆岩相似模型试验,采集人工激发微震波经由采空区结构传播的微震信号,通过变分模态分解(variational mode decomposition,VMD)处理微震信号,获取各频率下模态分量。针对采空区微震信号在VMD下各模态分量中心频率与能量之间的关系展开分析。根据中心频率法确定微震信号最佳模态数量,并计算微震信号欠分解状态、最佳分解状态、过分解状态下各分量能量;对各震源下信号最佳分解状态时各模态分量能量与中心频率分布关系进行拟合,分析在“三带”结构中,微震信号不同传播状态下各结构层对信号能量影响作用。研究结果表明:(1)在VMD过程中,人工激发震动信号有效模态数量在6~11范围内,微震信号能量随模态数量变化明显。(2)采用幂函数可实现对微震信号模态能量与频率关系的拟合,且拟合状态良好(决定系数大于0.9),其中低频模态分量包含能量占信号总能量近50%;采用高斯函数可以拟合震源各分量能量在频域上的分布表现,拟合状态较好,且表现出高斯单峰特征。(3)微震信号穿越采空区“三带”结构,微震信号能量随震源位置与传感器距离增加而减小,同时信号能量随震源位置到达传感器穿越岩层数量增加而减小,信号能量在经由垮落带时,能量变化明显,相较于裂隙带和弯曲下沉带,垮落带对信号能量衰减作用明显。

严寒地区被动房室内环境与供暖能耗后评估

对严寒地区某被动房示范项目的室内环境和供暖能耗进行了后评估,并与位于同一小区的普通住宅进行了对比分析。结果表明:被动房高性能的围护结构可有效提高室内操作温度,且由于设置了机械通风系统,可有效稀释室内CO_(2)浓度;被动房供暖季室内PM2.5浓度超标,新风系统对细颗粒物的过滤效率不满足要求;被动房供暖实际运行能耗高于超低能耗建筑年供暖耗热量指标,偏差达到33.6%。

考虑时段校核和季节性储能的多区互联电力系统年度发电计划

随着新能源发电量占比的提高,新能源发电量季节性波动引起的年度电力电量平衡问题更加明显。建立年度发电计划模型,提出一种典型时段校核方法;在年度发电计划制定的过程中引入季节性储能设备,建立季节性储氢模型和考虑水头位置的季节性抽水蓄能线性化模型;为了应对新能源出力的不确定性,提出考虑时段校核和季节性储能的年度发电计划三阶段建模方法。算例结果验证了所提模型的有效性。