槽式太阳能集热器传热模型及性能分析

槽式太阳能集热器一维和二维传热数学模型是一组非线性代数方程,为改进求解的稳定性和计算精度,将槽式太阳能集热器一维和二维传热模型的求解看作有约束优化问题,建立了集热器传热过程求解的有约束优化数学模型,应用MATLAB软件优化函数fmincon进行求解。分析了传热流体入口温度及太阳能辐射热流密度变化对集热器性能的影响。采用fmincon函数求解集热器传热过程,计算速度快,计算过程稳定。分析表明,传热流体温度变化对集热器效率的影响大于太阳能辐射热流密度对集热器效率的影响。     

基于KPCA-WLSSVM的建筑能耗预测模型

为降低建筑能耗影响因素间复杂相关性对模型性能的影响,建立了一种基于KPCA-WLSSVM的建筑能耗预测模型。利用核主元分析(KPCA)对输入变量进行数据压缩,消除变量之间的相关性,简化模型结构;进一步采用加权最小二乘支持向量机(WLSSVM)方法建立建筑能耗预测模型,同时结合一种新型混沌粒子群-模拟退火混合优化(CPSO-SA)算法对模型参数进行优化,以提高模型的预测性能及泛化能力。通过将KPCA-WLSSVM模型方法应用于某办公建筑能耗的预测中,并与WLSSVM、LSSVM及RBFNN模型相比,实验结果表明,KPCA-WLSSVM模型方法能有效提高建筑能耗预测精度。     

An exergy assessment model of the environmental impacts of building energy use

Buildings, as products of built environment creation made by human kind, consume a substantial amount of energy. Building energy performance attracts much attention from many countries. Two things building energy use affects are fossil energy co     

住宅建筑能耗基准确定及用能评价新方法

针对当前建筑能耗基准确定及用能评价方法仍不完善的现状,提出了一种适用于住宅建筑的新方法。通过灰色关联分析确定了不同影响因素(即特征参数)与建筑能耗的关联度,将关联度作为该因素的权值并结合聚类分析对建筑进行合理分类。在此基础上采用累积频率分布法确定了每类建筑的能耗基准值,并对建筑住户进行用能评价。为验证该方法的可行性,将其应用于日本建筑学会所建立的住宅建筑能耗数据库,为聚类后的每类建筑确定了相应的能耗基准并对住户进行了用能评价。结果表明该方法能够综合考虑不同特征参数的影响大小,科学合理地对建筑细化分类,根据分类后的基准评价能够更好地评估住户的节能潜力并提供可行的节能建议。     

Experiment and analysis of integrated application of solar energy andbuilding in Chongqing

According to the characteristics of the climate and distribution of solar resource in Chongqing, the technology idea of integrated application of solar energy and building is proposed, which is suitable for Chongqing area, i.e. solar assisted indoor ventilation cooling measure, which takes full advantage of the strong solar radiation in summer and strengthens the “chimney effect” to promote natural ventilation inside the building, improve the summer indoor hot and humidity environment, save energy and achieve solar energy passive using. Experiments and analysis show that the 0.16~0.22 m/s indoor air speeds are produced by the thermal effect of solar energy, which is increased by 14%~40%. And the average indoor temperature is 2.6~3.4 ℃ lower than the outdoor average temperature, and the indoor thermal comfortable state is effectively improved.     

气象参数对成都地区办公建筑能耗的影响及预测

气象参数是影响建筑热环境和供暖空调能耗的主要因素之一。基于成都地区1971—2000年共30 a的历史观测数据,生成了建筑能耗模拟软件EnergyPlus所需要的逐时气象数据文件。比较分析了该地区30 a干球温度、太阳辐射等各气象参数月均值的变化,模拟分析了该地区建筑的采暖、制冷及总能耗,利用多元回归建立了建筑能耗与气象参数之间的关系式,并检验了该关系式的准确性。结果表明：成都地区办公建筑能耗变化与各气象参数没有呈现明显的规律性;建筑月总能耗与各气象参数呈纯二次多项式关系,月采暖能耗、月制冷能耗与各气象参数呈交叉二项式关系;建筑月能耗回归模型能够较准确地预测建筑月能耗与各气象参数的关系,且月采暖能耗和月制冷能耗回归模型预测的准确性优于月总能耗模型。     

Water use efficiency of crops cultivated in the Mediterranean region: Review and analysis

Improvement of water use efficiency (WUE) of field crops in the Mediterranean region is an imperative imposed by the critical situation of water resources of the region, as well as by the demographical increment. This review reports the experimental data concerning WUE of 16 species cultivated in the region. The species include cereals, leguminous, horticultural and industrial crops. This review however underlines that WUE data of fruit trees are lacking, despite they represent one of the main productions of the Mediterranean agriculture.

In this region, the large range of WUE values observed, for the same species, can be ascribed mainly to: (i) fertilizers and water management (water regime, mineral supply and water quality); (ii) plant factors (species, variety and sensitivity of growth stage to the stress); and (iii) environmental factors (climate, atmospheric pollution, soil texture and climate change). The conclusion highlights the actual gap concerning WUE in the Mediterranean region. This gap will constitute a field of research designated to ameliorate WUE of agriculture in this region.     

绿色低碳约束下重庆能源DEA效率实证分析

客观评价重庆能源投入产出效益,探究环境污染、能源消费和经济增长之间的关系,进行能源结构优化,是当前重庆能源消耗走向绿色低碳方向发展面临的重大问题,也是重庆制定节能减排政策、能源发展战略和经济规划的重要基础。本文将能源投入和经济社会等产出因子科学分组,运用数据包络分析技术（DEA）,通过构建的能源需求结构方程以及DEA模型,对重庆能源消费进行了一系列DEA实证研究,得到了重庆能源投入产出规模效率在不同历史时期、不同阶段的变化规律,获取了能源冗余投入（径向改进和松驰改进）值、规模效应值、综合技术效率值和纯技术效率值,确定了DEA弱有效、DEA强有效、DEA完全有效的生产前沿面,并在此基础上对2016-2020年重庆能源结构进行了优化。研究成果可以为确定重庆能源绿色低碳发展方向、优化“十三五”重庆能源消费结构提供科学依据。     

A model for volume conduction energy transfer

One of the important technical problems of various implantable devices concerns effectively supplying sufficient energy to allow devices to work for extended periods, steadily and reliably. Presently, batteries and magnetic induction are only power supplies widely used in clinics. Because the capability of batteries is limited, implantable devices have shorter lives and low energy transfer efficiencies. We presented a means of transferring electrical energy into rechargeable batteries in implantable device by using volume conduction of biological organisms. An energy transfer model of volume conduction was created using ANSYS V10. We analyzed the energy transfer efficiency from simulation results and provide reference for further study of energy transfer of volume conduction.     

大型商场建筑夏季冷负荷动态预测模型

夏季建筑冷负荷的正确预测是实现大型复杂中央空调优化运行、节能降耗的关键。笔者探讨了商场建筑冷负荷的主要影响因素,确定了建筑动态冷负荷预测模型的输入,提出了夏季基于新风机组供电频率的商场顾客率间接测量方法,解决了商场内顾客量难以检测的难题。还提出了AFC-HCMAC神经网络预测模型算法,实现了大型商场建筑冷负荷的动态预测。仿真结果表明:顾客率在商场冷负荷预测中占有重要地位,在冷负荷预测模型中增加商场顾客率可显著提高预测精度;AFC-HCMAC神经网络预测算法与传统的HCMAC神经网络算法比较,可有效降低神经网络节点数,提高预测精度。     

围护结构热湿耦合传递模型及简便求解方法

为了预测围护结构内的温度和湿度分布,以连续变量,相对湿度和温度为驱动势,考虑热传递与湿传递之间的耦合作用,建立了围护结构热湿耦合传递非稳态模型,并提出了基于多物理场耦合仿真模拟软件COMSOL的热湿耦合传递模型简便求解方法。通过对比新建模型模拟结果与HAMSTAD标准验证实例,验证了模型及求解方法的准确性。     

Radiation interception and radiation use efficiency of near-isogenic wheat lines with different height

Resistance to Pyrenophora teres Drechs. f. teres Smedeg., the net blotch pathogen, was studied in six 6-row Nordic spring barleys (Hordeum vulgare L.) in the field and in the greenhouse. The barley genotypes were: Arve, Agneta, Artturi, H6221, Pohto and WW7977. Disease progress was monitored in the field (1994 and 1995) in small artificially infected plots, sown at commercial seeding rates, and in infected hill plots (1994). Areas under the disease progress curves (AUDPC) and apparent infection rates (r) were calculated for the uppermost 3 or 4 leaves. Terminal severities (TS) were also recorded. Infection response of seedlings to a range of P. teres isolates was assessed in the greenhouse using a standard scale. In small plots in the field, Arve and Agneta were very susceptible to P. teres infection, as indicated by large values for AUDPC and TS. H6221 and WW7977 were highly resistant, while Artturi and Pohto were moderately resistant. In hill plots the situation was similar, except that Artturi and Pohto appeared less resistant than in the small plots. The relatively greater resistance of H6221 and WW7977 was reflected in seedling infection responses. According to the results of these experiments, H6221 and WW7977 possess adequate levels of quantitative resistance to P. teres to make them useful parents in future crossing programs aimed at improving net blotch resistance in Finnish spring barleys. This revised version was published online in July 2006 with corrections to the Cover Date.     

基于人行为影响的住区建筑多主体集成能耗模型

在城市建筑节能研究中,政府常常依赖城市能源与碳排放模型工具制定并评估节能策略。而当前的城市建筑能耗模型受限于开发技术等因素,尚存在诸多不足,例如,考虑人行为对建筑能耗的影响,建立行为、日常活动及与环境相关的综合能耗模型。关于此类模型合理的数学形式、参数选择的方法以及不同行为的模拟方式等问题还尚待进一步研究。采用多主体（Multi-Agent）建模技术,设计集成建筑能耗模型,以住区中的居民作为模型中活动的主体,模拟使用者行为习惯、活动对建筑能耗的影响;采用ISO 13790标准模拟建筑的供热和降温需求,并在集成环境中设计统一的描述框架,以相对独立的环境模拟、行为模拟模块形式进行交互,实现热环境模拟和基于主体活动的设备能耗模拟的有机结合。研究表明,住区居民的用能行为是影响城市建筑能耗密度变化的重要因素,实现对住区主体行为特征的引导是实现城市建筑节能目标的有效途径。     

Evaluation of globe artichoke and related germplasm for resistance to artichoke latent virus

Summary A total of 280 globe artichoke (Cynara scolymus L.) clones were assessed for reaction to naturally occurring artichoke latent virus (ALV) in field trials. Also, the reaction of 17 seed progenies of crosses which produced ALV-resistant clones in the field, 20 self progenies of parental genotypes common to these crosses, self progenies of 17 artichoke cultivars, and 7 accessions ofC. cardunculus andC. syriaca were evaluated in the glasshouse following mechanical inoculation with ALV. The local and systemic presence of ALV, and the relative virus content in infected plants were determined by ELISA.All cultivars and most of the otherC. scolymus material tested (clones and seed progenies) proved to be highly susceptible to ALV. Ten progenies were less susceptible to mechanical inoculation as shown by the moment the virus could be detected, and a slow rate of accumulation of viral antigen. Some plants in two seed progenies possessed apparently a high resistance as could be concluded from the failure of ALV to spread or to multiply in plant.Accessions ofC. cardunculus andC. syriaca were also highly susceptible to ALV. However, an interspecific hybridC. cardunculus x C. syriaca presented the highest level of resistance, the plants remained free of local and systemic infection. Ratios of resistant to susceptible plants in self progenies of resistant plants suggested that this resistance was dominant.     

京津地区夏季着装行为对办公建筑空调能耗的影响

着装行为通过影响室内空气参数的设定而影响建筑空调能耗。利用能耗模拟软件DeST,计算出该地区典型着装行为下实测运行参数与期望参数对应的建筑空调能耗比推荐标准下能耗分别降低了10.86%和13.16%。而基于典型着装行为的实验热学性能参数下,平均只降低4%,说明由着装热阻关联的主观温度需要按地区着装行为进行修正。提出了控制建筑空调能耗的着装行为调节模型,着装行为节能率ε_c为负值时节能,为正值时不节能。京津地区办公建筑节能率为0的临界服装热阻为0.563 clo,空调系统设计和运行节能的前提是,着装热阻低于临界值。着装行为调节模型为地区着装形式和着装面料提供了量化标准,为精确控制建筑能耗提供了一种方法。     

Contribution of incident solar radiation on leaves and pods to soybean seed weight and composition

The weight and composition of soybean seeds (Glycine Max L. Merrill) depend on changes in carbon and nitrogen assimilate supply during grain filling. Soybean pods and seeds are green, evidencing their capacity to capture light. However, the current physiological knowledge does not consider any effect of incident solar radiation reaching the pods on seed weight and composition. The objective of this work was to investigate the response of seed weight and composition to changes in assimilate supply from leaves, to the incident solar radiation reaching the pods and to the combination of both, changes in assimilate supply from the leaves and incident solar radiation on pods of soybean plants. Field experiments were performed during two growing seasons at Balcarce, Argentina. Treatments modified the amount of assimilates supplied by the leaves (plant shading, defoliation), the solar radiation reaching the pods (pod shading) or both (defoliation and pod shading) during seed filling. Plant shading and defoliation reduced seed weight, oil concentration and oil and protein content and increased the concentration of saturated and poli-unsaturated fatty acids while reduced oleic acid percentage. Pod shading increased the concentration of stearic acid and reduced the concentration of linolenic acid. When pods were shaded on defoliated plants, seed weight and oil and protein content decreased while fatty acid composition was similar to values obtained under defoliation treatment. Based on these results, a conceptual model that considers photoheterotrophic nature of reproductive structures of soybean is proposed. Seed weight, oil and protein content and oil fatty acid composition depended on assimilate availability for the seeds. The response of oil and protein content to assimilate supply depended on whether leaves were present or not. The effect of solar radiation incident on pods depended on the amount of assimilates available for the seeds: (i) when carbon allocated was low (defoliation treatments), pods contributed to seed carbon economy but solar radiation incident on them did not affect fatty acid composition; (ii) when carbon allocated to the seeds was high (intact plants), contribution of pods to seed carbon economy was not significant, but the amount of solar radiation incident on pods produced significant changes in fatty acid composition.     

Determination of the weighing values of meteorological parameters in TMY of building energy consumption simulation

In the generation of the typical meteorological year（TMY）for building energy consumption simulation, the traditional Finkelstein-Schafer statistical method given fixed weighting factors to the meteorological parameters, but the relevant studies showed that there was debate for the curing of weighting factors of meteorological parameters due to the different regional meteorological resources. Aiming at the weighting factors of metorological parameters unity or not in selection of TMY and the impact of building energy consumption simulation, Beijing and Lhasa on behalf of the cold region in building thermal partitions, based on the methods of FS and principal component analysis（PCA）was analyzed. The results showed that the FS statistical method is suitable for the similarity characterization of meteorological parameters for a long time and suitable for the solar energy rich area, there is too much weight given to solar radiation parameters across the country; and the PCA method is suitable for the essential characteristics of the local meteorological resources, choice of meteorological parameters is particularly important when using this method.     

Productivity and radiation use efficiency of lettuces grown in the partial shade of photovoltaic panels

Combining photovoltaic panels (PVPs) and crops on the same land unit were recently proposed as an alternative to the conversion of cropland into photovoltaic plants. This could alleviate the increasing competition for land between food and energy production. In such agrivoltaic systems, an upper layer of PVPs partially shades crops at ground level. The aim of this work was to (i) assess the effect on crop yield of two PVPs densities, resulting in two shade levels equal to 50% and 70% of the incoming radiation and (ii) identify morphological and physiological determinants of the plant response to shade. Experiments were conducted on four varieties of lettuces (two crisphead lettuces and two cutting lettuces), during two seasons. In all cases, the relative lettuce yield at harvest was equal or higher than the available relative radiation. Lettuce yield was maintained through an improved Radiation Interception Efficiency (RIE) in the shade, while Radiation Conversion Efficiency (RCE) did not change significantly. Enhanced RIE was explained by (i) an increase in the total leaf area per plant, despite a decrease in the number of leaves and (ii) a different distribution of leaf area among the pool of leaves, the maximal size of leaves increasing in the shade. Our result provides a framework for the selection of adapted varieties according to their morphological traits and physiological responses to PVP shade, in order to optimize agrivoltaic systems.     

Embodied-carbon analysis of renewable energy utilization system

Based on the energy analysis theory and carbon footprint analysis, it presents the concept of embodied-carbon and sets up the relevant systematical analysis method and assessment indexes such as CO2 payback period, benefit-cost ratio, CO2 emissions reduction transformity to assess the renewable energy utilization system. These indicators can be a comprehensive evaluation of the utilization of renewable energy in the energy saving and CO2 emission reduction. It analyzes and evaluates photovoltaic power generation system by using the embodied-carbon analysis method and evaluates the potential of solar energy utilization in China.     

Dual energy X-ray image analysis for classifying vitreousness in durum wheat

Dual energy X-ray imaging technique is an alternative to simple transmission X-ray imaging. The former has the ability to reveal the internal density changes of a scanned object by exploiting differences in how the scanned material interacts with X-rays at different energies. The feasibility of dual energy X-ray image analysis to classify vitreousness in durum wheat was assessed at 12, 14 and 16% moisture content (m.c.). Algorithms were developed for the logarithmic subtraction of images and for extraction of features. Histogram groups and total gray values were extracted from the dual energy subtracted images. Statistical and neural network classifiers were used for identifying vitreous and non-vitreous kernels from the sample images. Neural network classifiers correctly classified vitreous and non-vitreous kernels with 93% accuracy. The statistical classifiers provided 89% accuracy for vitreous and non-vitreous kernels. The over all classification accuracy for differentiating vitreous and non-vitreous kernels is higher using dual energy X-ray imaging than the simple transmission X-ray imaging.