分散式天然气采暖的应用测试

分散式燃气采暖设备———安装在一家一户内的燃气采暖炉，在国外已经有几十年应用的历史。采用这种方式供暖的主要优点是：洁净，燃气产生污染物少；节能，没有供热一次、二次管网及热交换站的热损失，可节省７％左右的热能；舒适，用户可以根据自己的需要随时调节供暖温...     

基于PC实现二次仪表型消光式烟度计的数据实时采集

通过对二次仪表的改造，实现了基于个人计算机的二次仪表型烟度计的数据实时采集，解决了二次仪表型烟度计不能反映摩托车瞬间排烟状况和数据采集不准的问题，并实现了软件的自校功能，弥补了二次仪表的自校缺陷；同时添加了数据的奇异性检验，消除了因试验环境的干扰所造成的奇异数据。采集数据可根据不同的试验方法进行数据处理、存盘与打印相关试验报告。     

超声波流量计在南水北调东线泗阳站的应用

介绍了多声路超声波流量计在南水北调东线泗阳站应用的测点布置和采用的声路，并结合机组模型试验证其测量精度，最大误差为0．52％，说明多声路超声波流量计完全可以满足泗阳站工程需求，同时结合流量测量正反转模型试验分析，为南水北调东线泵站多声路超声波流量计的安装位置、声路选择和测量精度确定提供参考。     

光电型总日射表性能的初步研究

对光电型总日射表与ＰＳＰ型总日射表进行了对比测试。在带有圆柱形余弦修正器时光电型总日射表的灵敏度尚佳。在太阳高度角小型３５°、没有温度补偿或将传感器与二次仪表做成一体时其误差较大     

强直流测量校验仪器的研究

一、概述 在许多冶金、化工企业中,成千上万安培的强大的直流电流常年不断地流进电解槽,其用电量占全国总发电量的20～40％,耗电惊人。国内一般计量直流大电流的直流互感器和分流器精度不高,耗电量大,线性度差,不便于装拆。二次仪表又大都采用板式仪表.精度低、直流大电流不能准确计量,不仅影响电能的有效利用,甚至影响到生产工艺过程的优化控制、电解设备的寿命和产品的质量。因此,对强直流测量校验仪器的研究十分必要,需要解决的关键问题是:①研制精度高、线性度好、耗电量少,防磁能力强、便于现场使用、装拆的一次直流大电流传感器。②研制测量精度高、功能全、体积小、成本低的二次仪表。     

加导流板对燃烧器一、二次风混合位置影响的研究

燃烧器一、二次风混合位置是燃料丰火稳燃的关键。文中介绍了在燃烧器喷口采用加装导流板的方法，推迟二次风混入一次风气流中，并利用正交试验及方差分析研究导流板的结构及安装尺寸对混合位置的影响，得到对混合位置影响最大的因素。对工程设计有重要指导意义。图2表4     

液浸式变压器测温装置两表偏差缺陷的解决方案

分析了液浸式变压器测温装置两表偏差缺陷的主要原因,结合国内外标准要求及试验方法对产生两表偏差的原因进行了测试验证,并通过对不同因素的误差分析,得出采用全天候准确度测温装置能够从源头上消除由于环境温度影响造成的两表偏差缺陷.     

对柴油机活塞裙部椭圆直径测量方法及换算公式的研讨

<正> 由于柴油机活塞裙部椭圆直径的传统测量及换算方法,几乎完全忽视了止口与定位凸台间隙以及环境温度变化等因素对测量值的影响,因此测最结果误差较大,尤其是在止口与定位凸台间隙大、环境温度改变显著的特殊场合,采用传统测量及换算方法很可能将实质上是合格的柴油机活塞误认为是超差的次品(见表1)。为了提高测量精度,精确地反映柴油机活塞裙部椭圆直径的真实     

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柴油机质量的简易鉴别方法有哪些？答：一台新的或大修后的柴油机，鉴别其质量的简易方法通常可包括以下评定项目和要求．1．1＃机性能1．1．l起动性能柴油机在各种环境温度条件下，若准备上作完好和起动方法正确，应能顺利迅速起动．电起动的柴油机，在环境温度不低于OC时，起动次数不应多于3次，累计时间不超过10秒钟．手扶拖拉机由于采用人工手摇起动，因而要求当环境温度不低于5C时，起动时间应不超过2分钟．若低于SC；需按各机型说明书规定的预热方法进行预热，并也应能及时正常起动．如若不然，则说明柴油机起动性能不良．1．1．2空…     

谈采用便携式仪表测量高压用电设备的输入／输出功率

归纳了高压用电设备电压、电流互感器的常见故障现象，并通过在故障情况下对输入便携式仪表所测电流电压之间相位、相量关系的分析，总结出在高压用电设备二次计量端正常及常见故障情况下，采用便携式仪表测量其输入／输出功率的测试与计算方法。     

Attainment of temperature equilibrium in holes during drilling

A fitting function for the time-temperature curve of deep wells was proved, which enables a sufficient accuracy (2–3%) in extrapolation at temperature equilibrium value. This function is based on the study of thermal transients resulting from disturbances induced by drilling operations.Analyses began on the basis of many thermometric measures taken by ENEL during the last 10 years in shallow geothermal holes. They proved that a 3-parameter logarithmic law can be used to interpret the asymptotic behaviour. On the other hand extrapolation from comparatively short measuring times (20–30 hours) with a function of an asymptotically logarithmic type was performed by means of a 4-parameter relation involving the integral exponential function.     

Calibration of pyranometers

Methods currently used for calibrating pyranometers and some probable errors which may arise are discussed. Some important precautions that must be taken which could improve these methods are indicated.Two new calibration methods using a sub-standard pyranometer as reference are described. The first of these methods consists of direct comparison of the outputs of the sub-standard and working pyranometer on a X-Y recorder. The limitations of this method are discussed.The second method is independent of clear sky conditions. The pyranometer to be calibrated is compared with a sub-standard instrument placed in the same aspect and nearby. The output from the two instruments, or more if need be, is fed directly to a computer data acquisition system. The output from the computer, including calibration constant, real solar time, and ambient temperature in the form of BCD information on paper tape is later fed to a larger computer for statistical analysis. Correlations of calibration coefficient against time (position of the sun) and ambient temperature have been made.Results of calibrations carried out by this method for various designs of pyranometers are given for various climatic conditions. The probable limit of accuracy of this method is discussed with special reference to its advantages over more conventional methods. Other meteorological parameters that could be usefully included in the analysis are considered.     

涡街流量计测量系统不确定度的分析

通过分析涡街流量计在液体和气体流量测量应用中的工作原理,讨论了涡街流量计测量系统中仪器尺寸精度、斯特劳哈尔数、涡旋频率测量、温/压测量以及其它环节的系统不确定度分量和不确定度的合成。通过对测量系统不确定度的分析,提出了涡街流量计测量系统的改进方向以及涡街流量计的干标定问题,促进节能减排工作的进展。     

An experimental study of a cross-flow type plate heat exchanger for dehumidification/cooling

The thermal and dehumidification behaviour of a standard cross-flow type plate heat exchanger, intended for use as a dehumidifier/cooler, has been investigated both experimentally and numerically. Three sets of experiments have been carried out where air is blown into the primary and secondary sides of the exchanger, while water and liquid desiccant were being sprayed in a counter flow arrangement. The first set represents the indirect evaporative cooling of the primary stream by the secondary air stream. The second set is with liquid desiccant only and no indirect evaporative cooling. In the third set of experiments the primary air stream is indirectly evaporatively cooled by the secondary air stream and dehumidified by the liquid desiccant sprayed into the primary side of the exchanger. The above experiments indicate that the heat exchanger performs well when used with liquid desiccant. Furthermore, for an exchanger angle of 45°, there is an optimum value of air mass flow rate at which the effectiveness and dehumidification efficiency of the plate heat exchanger are maxima. To investigate the effect of the ambient air conditions on the PHE performance, further experiments were carried out using a heater element and a humidifier. The results show that under laboratory conditions the exchanger effectiveness and dehumidification efficiency increase with increasing primary air inlet temperature and humidity ratio. The experimental results were used to validate a computer model developed for the cross-flow type plate heat exchanger/dehumidifier. Comparison indicates that the numerical results are in good agreement with the experiments.     

Heating and cooling potential of an earth-to-air heat exchanger using artificial neural network

In this article, we use the concept of artificial neural network and goal oriented design to propose a computer design tool that can help the designer to evaluate any aspect of earth-to-air heat exchanger and behavior of the final configuration. The present study focuses mostly on those aspects related to the passive heating or cooling performance of the building. Two models have been developed for this purpose, namely deterministic and intelligent. The deterministic model is developed by analyzing simultaneously coupled heat and mass transfer in ground whereas the intelligent model is a development of data driven artificial neural network model. Six variables influencing the thermal performance of the earth-to-air heat exchangers which were taken into account are length, humidity, ambient air temperature, ground surface temperature, ground temperature at burial depth and air mass flow rate. Furthermore, a sensitivity analysis was carried out in order to evaluate the impact of various factors involved in the energy balance equation at the burial depth. The model was validated against experimental data sets. Moreover, the developed algorithm is suitable for the calculation of the outlet air temperature and therefore of the heating and cooling potential of the earth-to-air heat exchanger system. The Intelligent model predicts earth-to-air heat exchanger outlet air temperature with an accuracy of ±2.6%, whereas, the deterministic model shows an accuracy of ±5.3%.     

Design and optimization of Isochoric Differential Apparatus (IDA) to reduce uncertainty in H2 sorption process measurements

The quantification of hydrogen absorption and desorption in materials is a crucial step for the assessment of proper storage solutions and their applications. Unfortunately, volumetric instruments are in many cases affected by low accuracy due to several factors such as temperature uncertainty and misleading on calibration proceeding.In this work, we report the superior performance of a new kind of instrumental layout to characterize kinetics and thermodynamics properties of hydrogen storage materials. Hereby presented system is based on differential Sievert measurements, defined as Isochoric Differential Apparatus (IDA). IDA includes two coupled identical Sievert apparatus where pressure values are sampled in differential mode to compensate all temperature transient phenomena and nonlinear effects occurring during the gas expansion step that occurs during the measurements. A physical model to evaluate the sorbed gas at non-isothermal condition has been developed and reported. Detailed error analysis of the kinetic and thermodynamic models has been carried out considering a real gas. Palladium and Magnesium has been utilized as benchmark materials, to test the differential apparatus at ambient and high-temperature values > 300 °C). For both materials, kinetic and thermodynamic properties have been acquired by the differential layout in well agreement with reference data and with a higher accuracy than classic Sievert instrument, involving in identical size of expansion volume. This work demonstrates as the differential layout allows to reduce uncertainty in hydrogen sorption measurement exploiting the full accuracy of equipped transducers. At this level of performance, the impact of calibration procedures and the approach for the estimation of compressibility factor become extremely important to further reduce uncertainty on sorption measurements.     

Production of hydrogen-rich gas from plant biomass by catalytic pyrolysis at low temperature

The catalytic pyrolysis of plant biomass was investigated in a dual-particle powder fluidized-bed (PPFB), where the primary decompositions and secondary reactions occurred simultaneously under ambient pressure. The yields and distributions of the pyrolysis products were studied under various operating conditions. In the absence of catalyst, the amount of volatile released from woody biomass depended on the pyrolysis temperature, and only 13.8 g H₂/kg biomass (def: dry ash-free basis) was produced at 1173 K. NiMo/Al₂O₃ catalyst promoted the decomposition of tar and light aromatic hydrocarbon compounds from the primary decomposition reaction, and significantly reduced the temperature required for the secondary phase reaction. With NiMo/Al₂O₃ catalyst at 723 K, clean combustion gas accounted for 91.25 vol% of the total gas products, which was composed of 49.73 vol% of H₂, 34.50 vol% of CO, and 7.03 vol% of low molecular weight hydrocarbon gases. The contents of H₂ and CO were 33.6 g H₂/kg biomass (def) and 326.3 g CO/kg biomass (def), respectively. Therefore, it is critical to control the secondary phase reaction conditions during the catalytic pyrolysis in order to produce hydrogen-rich gas.     

Experimental and thermal analysis of energy efficient novel design wet cooling towers

Waste heat is generally dissipated from process water to atmospheric air in cooling towers. In the present study, a novel design is used to extract more amount of heat without any additional energy input by incorporating secondary ambient air in an induced draft wet cooling tower. In addition, more fresh air is induced in the tower from the rain zone, which increases the effectiveness at any value of the water to air flow rate (L/G ratio). Moreover, tower characteristics, range, and evaporation loss were also increased due to the novel design. It is noteworthy that secondary fresh air increases effectiveness, heat rejection, and tower characteristics by 10.12%, 19.65%, and 26.11%, respectively, and decreases approach by 16.32% at 0.55 L/G ratio, 44°C inlet water temperature, 29.7°C dry bulb temperature, and 18.4°C inlet air wet bulb temperature.     

Influence of the temperature and hydraulic retention time in bioelectrochemical anaerobic digestion of sewage sludge

At ambient temperature (25 °C), bioelectrochemical anaerobic digestion of sewage sludge was investigated with a hydraulic retention time (HRT) of 10 days and compared to that at a mesophilic condition (35 °C). The methane production and methane content in the biogas at ambient temperature were 612.8 mL/L·d and 73.3%, respectively, which were not significantly lower than that of the mesophilic condition. Additionally, the VS removal was 54.5% which was similar for both temperature conditions. However, for a HRT of 20 days, the bioelectrochemical anaerobic digestion at ambient temperature became more stable, and the VS removal improved up to 65.0%. For the HRT of 10 days, the net energy production at ambient temperature was about 168 kJ/L·d, which was similar to the mesophilic condition; however, the apparent energy efficiency at ambient temperature was 249.2% which was significantly higher than 197.7% at the mesophilic condition. The bioelectrochemical anaerobic digestion that can save the thermal energy input at ambient temperature is recommended for the treatment of organic waste including sewage sludge in moderate and cold climate regions.     

State of charge estimation in electric vehicles at various ambient temperatures

The battery state of charge estimation at various ambient temperatures is critical to keep the electric vehicles safety. To solve the problem of battery model parameters vary with temperature, this work proposes a lithium-ion battery model with temperature effect and a state of charge estimation method at various ambient temperatures. The battery capacity and the open circuit voltage are fitted to establish the connection with temperature, respectively. Dual extended Kalman filters estimate the battery impedance. The experiments show that the lithium-ion battery model with temperature effect has high accuracy at different temperatures. Low temperature has a significant impact on battery model parameters. The proposed method does not need to store many battery model parameters' offline data and reduces the amount of experimental calibration for battery model parameters. The proposed method has a maximum error within 2% at various ambient temperatures. Moreover, the proposed method is robust to the initial state of charge value.