海口市某高级酒店全年运行能耗统计与分析

对海口市某高级酒店的全年运行能耗进行统计分析,结果表明:该酒店单位面积总能耗为167.6k Wh/(m~2·a),其中单位面积总用电量为150.9k Wh/(m~2·a),所占比例为90.1%,在该地区处于中等偏高比例水平。酒店月用电量与月平均气温变化趋势基本一致,月用水量与月平均最低气温变化趋势更为接近,而月用气量与月平均入住率变化趋势基本一致。空调系统用电量占总用电量的比例为50.9%,机组经常处于低负荷运行状态,平均负荷率仅68.6%,是造成空调系统用电量偏高的重要原因之一,且在夏热冬暖地区酒店类建筑能耗中具有普遍性,存在较大的节能潜力,为类似气候地区酒店建筑的综合节能改造与优化运行管理提供有益的技术参考。     

基于K-L信息量法的安徽省工业用电量预测

针对区域工业用电量与经济指标的相关性,运用K-L信息量法,在月度尺度上筛选出能够指示区域工业用电量变化趋势的经济先行指标,并获得各先行指标的先行期数。以经济先行指标为自变量、区域工业用电量为被因变量建立多元回归模型,根据AIC准则和BIC准则选取最佳拟合方程,得到工业用电量预测模型。运用模型预测安徽省2014年5月-12月的月用电量,结果显示预测精度较高,预测方法可以用于工业用电量预测。     

要闻

国家能源局：用电量指标确认经济已企稳回升 10月14日,国家能源局发布9月份全社会用电量等数据。9月份,全社会用电量4448亿千瓦时,同比增长10．4％。继8月份实现同比增长13．7％的最高涨幅后,全社会用电量继续保持了快速增长势头。作为经济的“晴雨表”,自5月份起全社会用电量增速保持连续5个月回升,充分印证经济企稳同升的态势。     

浅谈电梯节能技术

随着现代化生产规模不断扩大，高层建筑的增多，电梯数量飞速增长，而据调查统计，在宾馆、写字楼等的用电情况中，电梯用电量占总用电量的20％-30％以上，仅次于空调用电量．高于照明、供水等的用电量。在日前用电紧张的情况下，节电呼声日益高涨．如何采用节能的电梯主机以及电梯的节能技术，已经成为人们十分关注的事。     

地热盖层中井温梯度与地温梯度的关系及应用

在曲阜市地热地质普查中，发现井温梯度与地温梯度的关系，从理论与实际勘探工作中充分说明和验证了地热盖层地温与井温梯度差的客观存在规律。井温梯度同比于地温梯度，井温梯度与地温梯度存在一固定差值，地温梯度与井温梯度之差为2．6℃/100m。     

基于大工业用户的远程费控系统模型设计及分析

针对大工业用户用电量在不同时期差异明显且传统远程费控系统设计复杂、精确度低的问题,首先对大工业用户用电量进行了对比分析;其次,设计适用于大工业用户不同工作时期的基于开关函数的远程费控开关模型系统;最后,与传统远程费控模型对比验证。实例表明,本文设计的远程费控系统依据开关函数在次月能够对前一月预警情况进行补偿,使得其效果相较于传统远程费控模型更加精确可靠。     

我国与国际能源署用电量指标对比分析

为准确开展我国与世界主要国家用电量及其行业构成的国际比较,从行业用电构成方面为我国产业结构调整提供国际经验借鉴,本文对我国国家统计局与国际能源署用电量统计口径、内涵和终端用电分类进行了对比分析。结果表明,双方在用电量指标的分类和内涵上均有所区别,国家统计局用电量口径大于国际能源署,工业用电比重偏大;2000年到2012年间,国家统计局统计的我国用电量和人均用电量数据约是国际能源署相应数据的1.06~1.07倍,国家统计局统计的2012年我国终端工业用电比重与国际能源署口径相比高3.4个百分点,而居民、商业服务业用电比重相比则分别低1.8和2.3个百分点。建议在开展中外用电量的国际比较时,准确区分中外用电量的统计口径,正确应用统计数据。     

东北振兴以来地区用电量与经济增长相互关系分析

自东北振兴战略实施以来,东北地区经济增长经历了高速发展、断崖式下滑、新常态等多个发展模式。地区用电量作为经济运行的"晴雨表",与经济增长之间的相互关系也呈现出多样性特点。通过对2003～2018年地区GDP增长情况与全社会用电量增长情况的比较分析可知,随着经济增速放缓,用电量下滑更为明显。2012年地区经济进入新常态,特别是当2015年地区经济增速出现明显滑坡时,用电量与经济增长出现了短期背离现象。用电结构变化趋势与产业结构调整趋势基本保持一致。东北地区万元GDP电耗呈波动性下降态势,由2003年的1374.7kW·h下降至2018年的1338.3kW·h,经济发展的质量效益取得一定成果。东北地区用电量与经济发展关系变化的原因包括产业结构调整、高耗能产品去库存以及节能工作的深入开展。分析表明,东北地区用电量与经济发展仍具有较强的相关性,变动趋势基本一致,但用电量变化幅度较GDP更为敏感、显著。随着地区经济进入新常态,对用电量的"晴雨表"作用不应仅从总量增长上进行分析,而应从分产业、分行业等更为细致的方面进行多维度、精细化的研究。     

基于逐步回归分析的用电量预测

文中针对用电量预测的多元线性回归模型，提出了逐步回归分析方法。与传统的多元线性回归模型相比较，逐步回归分析方法无需建立全部变量的回归方程，而是在全部自变量中按对因变量的作用大小，边进行显著性检验，边入选或剔除变量，不重要变量始终不进入回归方程，最后形成重要变量的最优回归方程。实例计算分析表明，与多元线性回归模型预测方法相比较，逐步回归预测模型对用电量的预测是有效的。     

BP网络模型在大型泵站用电量预测中的应用

针对大型泵站年用电量的非线性规律，提出应用BP网络模型的预测方法。该方法采用误差逆传播学习规则，具有较强的非线性拟合能力，实例计算分析表明，与线性回归模型预测方法相比较，BP网络模型对大型泵站年用电量的预测是有效的。     

Weather, the estimation of residential energy demand relationships and the reporting of data

The need for adjusting energy related data, especially weather data, prior to estimating demand relationships is pointed out. A previous study by Rushdi in Energy Economics and other studies are used as examples. The lack of such adjustments could affect greatly the estimated results. The desirability of making data available along with an article is also pointed out.     

Sulfur gas emissions from geothermal power plants in Iceland

Sulfur gas (H₂S and SO₂) emissions from geothermal fields in Iceland have been studied as part of a project, aimed at enhancing environmental research concerning effects of geothermal development. Short-term measurements of the gases have been carried out in several high-temperature geothermal fields in Iceland. In four exploited fields, baseline values for the concentration of sulfur gases have been obtained by long-term measurements. The data strongly reflect the dependence of gas concentrations on climatic factors, especially precipitation. Interpretation of the data by air distribution modeling, and by simple experiment, indicate minor, or at least very slow conversion of H₂S to SO₂ at atmospheric conditions in Iceland.     

Effects of ambient temperature and humidity on the controlled cooling of hot-rolled wire rod of steel

The effects on the controlled cooling of hot-rolled wire rod of steel at different ambient temperature and humidity have been investigated. The results indicate that the convective heat-transfer coefficients and heat flux increase as humidity increase and temperature decrease. And it results in the increase of cooling rate and the decrease of phase transformation temperature of steel. According to the empirical relationship between the isothermal transformation temperature and experimental results of ultimate tensile strength with steel of SWRH82B and diameter of 12.5 mm, the maximum ultimate tensile strength (UTS) is 1206 MPa at −15 °C and humidity level of 100%, and the minimum UTS is 1139 MPa at 55 °C and humidity level of 0%. The predicted results agree well with the inspection results of industrial trials. And then, some references of the optimal outputs of blower have been provided for stabilizing product quality.     

Mathematical representation of a few chosen weather parameters of the capital zone ‘Damascus’ in Syria

This work presents a mathematical representation of a few chosen weather parameters of the capital zone ‘Damascus’ in Syria.Seasonal models, as an alternative to the use of hourly historical weather data, were suggested and used to generate synthetic weather data for the following parameters:

– relative humidity;

– atmospheric pressure;

– wind speed;

– global solar radiation intensity.

Such mathematical models were derived for the heating season (November to April) and for the air-conditioning season (June to September) in the zone involved. Moreover, daily sunshine-hours rate was also represented by single model throughout a year. These models were developed based on long time records of data.The choice of the best model was based on three statistical parameters: the coefficient of determination R², the mean relative error e_m and the t-test.The predicted values along with the recorded data were plotted on the same scale in order to consider a visual comparison between them. It is visually noticeable that good agreement between the predicted and observed data values was obtained.The question of whether both, the stochastic and deterministic components of the analyzed weather parameters have to be included in building thermal performance calculation was investigated. It was demonstrated that on an hour-to-hour basis, the stochastic component may be disregarded in building thermal performance calculations without significantly affecting the results.     

Influence of different outdoor design conditions on design cooling load and design capacities of air conditioning equipments

Outdoor design conditions are important parameters for energy efficiency of buildings. The result of incorrect selection of outdoor design conditions can be dramatic in view of comfort and energy consumption. In this study, the influence of different outdoor design conditions on air conditioning systems is investigated. For this purpose, cooling loads and capacities of air conditioning equipments for a sample building located in Adana, Turkey are calculated using different outdoor design conditions recommended by ASHRAE, the current design data used in Turkey and the daily maximum dry and wet bulb temperatures of July 21st, which is generally accepted as the design day. The cooling coil capacities obtained from the different outdoor design conditions considered in this study are compared with each other. The cost analysis of air conditioning systems is also performed. It is seen that the selection of outdoor design conditions is a very critical step in calculation of the building cooling loads and design capacities of air conditioning equipments.     

A new scheme for cooling tower water conservation in arid-zone countries

Cooling towers (CTs) that are used for heat rejection in water-cooled (WC) systems consume a large quantity of water, which is generally not available naturally. CTs are selected when the maximal cooling load is desired and under the worst design conditions. Typically, CTs operate under partial-load conditions and/or favorable weather conditions. Moreover, for most of the summer season, the dry bulb temperature (DBT) of the incoming ambient air is significantly greater than the incoming hot water temperature, and the air undergoes sensible cooling. Currently, the control scheme that is commonly used in most CTs maintains a constant exiting water temperature for different cooling loads and a different ambient wet bulb temperature (WBT) by regulating the air circulation through the CT. The air circulation is reduced with the help of a variable frequency drive (VFD), which results in a significant reduction in the fan power of the CT. This paper presents an assessment of CT performance with a VFD application using a computer simulation program and illustrates a proposed scheme for maximal water savings. These theoretical results demonstrated that reducing the air flow by applying a VFD in a CT can achieve at least a 25% reduction in water consumption.     

Impact of different weather years on the design of hydrogen supply pathways for transport needs

Renewable energy sources (RES) will play a crucial role in future sustainable energy systems. In scenarios analyzing future energy system designs, a detailed spatial and temporal representation of renewable-based electricity generation is essential. For this, sufficiently representative weather data are required. Most analyses performed in this context use the historical data of either one specific reference year or an aggregation of multiple years. In contrast, this study analyzes the impact of different weather years based on historical weather data from 1980 through 2016 in accordance with the design of an exemplary future energy system. This exemplary energy system consists of on- and offshore wind energy for power-to-hydrogen via electrolysis, including hydrogen pipeline transport for most southwestern European countries. The assumed hydrogen demand for transportation needs represents a hypothetical future market penetration for fuel cell-electric vehicles of 75%. An optimization framework is used in order to evaluate the resulting system design with the objective function of minimizing the total annual cost (TAC) of the system. For each historical weather year, the applied optimization model determines the required capacities and operation of wind power plants, electrolyzers, storage technologies and hydrogen pipelines to meet the assumed future hydrogen demand in a highly spatially- and temporally-detailed manner, as well as the TAC of the system. Following that, the results of every individual year are compared in terms of installed capacities, overall electricity generation and connection to the transmission network, as well as the cost of these components within each region. The results reveal how sensitive the final design of the exemplary system is to the choice of the weather year. For example, the TAC of the system changes by up to 20% across two consecutive weather years. Furthermore, significant variation in the optimization results regarding installed capacities per region with respect to the choice of weather years can be observed.     

基于聚类分析的短历时暴雨雨型研究

暴雨雨型直接影响着洪峰流量的大小及洪水过程,研究暴雨雨型可为防洪排涝、山洪灾害防治提供科学依据.根据陕西省宝鸡气象站1981～2017年自记降雨资料,采用Ward聚类分析法对120场暴雨做了分类研究,从多角度分析了雨型的发生规律,初步探讨了雨型与山洪内涝的关系.结果 表明,聚类分析法在雨型分类中具有较好的适用性;宝鸡气...     

Modeling solar still production using local weather data and artificial neural networks

A study has been performed to predict solar still distillate production from single examples of two different commercial solar stills that were operated for a year and a half. The purpose of this study was to determine the effectiveness of modeling solar still distillate production using artificial neural networks (ANNs) and local weather data. The study used the principal weather variables affecting solar still performance, which are the daily total insolation, daily average wind velocity, daily average cloud cover, daily average wind direction and daily average ambient temperature. The objectives of the study were to assess the sensitivity of the ANN predictions to different combinations of input parameters as well as to determine the minimum amount of inputs necessary to accurately model solar still performance. It was found that 31-78% of ANN model predictions were within 10% of the actual yield depending on the input variables that were selected. By using the coefficient of determination, it was found that 93-97% of the variance was accounted for by the ANN model. About one half to two thirds of the available long term input data were needed to have at least 60% of the model predictions fall within 10% of the actual yield. Satisfactory results for two different solar stills suggest that, with sufficient input data, the ANN method could be extended to predict the performance of other solar still designs in different climate regimes.