Development of a novel mop fan

A novel fan that operates as an air moving device as well as a filter has been investigated. The unit utilizes a brush disk, instead of bladed impellers, within a centrifugal fan casing and is known as a ‘mop fan’. The performance of the mop impellers as fans was tested and their characteristic curves were found to be similar to those of centrifugal fans. The characteristics of the mop fan in terms of airflow rate, pressure, and efficiency were tested using a standard method, BS 848. The tests allowed mops of different fibre number and fibre diameter to be constructed and so optimize mop fan performance. Copyright © 2001 John Wiley & Sons, Ltd.     

300MW机组直吹式制粉系统通风量优化试验及分析

为解决直吹式制粉系统一次风机电耗较大、中速辊式磨煤机静环吹损较严重、煤粉细度偏小等问题,通过对磨煤机出口一次风速、磨煤机入口风压等关键点的控制,较系统的优化制粉系统通风量,达到降低能耗、提高锅炉效率的试验目的,对同类型机组的优化试验有一定借鉴意义。     

高温空气发生器冷态实验研究

概述了发展生物质高温空气气化(HTAG)系统的必要性,为进行生物质高温空气气化的研究,研制了关键部件—高温空气发生器实验装置,并在此装置上进行了冷态实验,结果表明：冷态实验条件下,高温空气发生器可以正常稳定运行,并可以进行下一步热态实验研究;通过冷端调节可以实现高温空气的分流,并且分流出口的流量和压力随鼓风机开度的增大和排烟机开度的减小逐渐增大;进入燃烧室的高温空气量及其流速与鼓风机开度无关,是随排烟机开度的增大而增大。     

A comparative study on energy consumption for HVAC systems of high-tech FABs

The unique system dynamics of five different HVAC designs including the RCU (recirculation air unit) system, the MAU (make-up air unit) + RCU system, the MAU + RCU + FCU (fan coil unit) system, the MAU + axial fan system, and the MAU + FFU (fan-filter unit) system for a typical 200 mm DRAM wafer fabrication plant are discussed and compared. The energy performances of the RCU system, the MAU + RCU system, the MAU + RCU + FCU system, and the MAU + axial fan system are 3.8, 1.19, 1.12 and 1.08, respectively, folds that of the most efficient MAU + FFU system. The MAU + axial fan system exhibits slight less efficient in energy performance, compared with the MAU + FFU system. The most influential factor on energy performance between these two systems is the design of the noise abatement system, especially the pressure drop of the silencer, which dominates almost half of the internal static pressure of axial fan. When the static pressure of silencer of the MAU + axial fan system is reduced to 50 Pa, energy consumption of these two systems is comparable. Bypassing a certain portion of FAB return air to mix with make-up air can maximally reduce 50% of energy consumption of the RCU system.     

Using multi‐stack and variable‐speed‐drive systems to reduce laboratory exhaust fan energy

In buildings that contain laboratories, fume hoods are normally used to control contaminant concentrations. Exhaust stacks with a constant exit velocity are required to make sure that dangerous concentrations do not occur in occupied areas near the building or on the roof top. To achieve constant velocity when exhaust flow rates are less than design, makeup air is introduced to the system at the inlet of the exhaust fan. Since laboratory exhaust airflow is often significantly less than the design airflow, exhaust fans consume significantly more energy than is necessary. To reduce exhaust fan energy, techniques involving multiple exhaust stacks and a variable speed drive (VSD) can be applied to laboratory exhaust systems. The potential fan energy savings depend on optimal selection of the number of stacks, the sizes of the stacks, and the exhaust system ductwork design. This paper introduces application principles, describes the optimal methods of stack sizing, and presents an example to demonstrate these methods. Published in 2005 by John Wiley & Sons, Ltd.     

Comparative performance and emission studies for vaporized diesel fuel and gasoline as supplements in swirl-chamber diesel engines

An experimental study has been conducted to evaluate and compare the use of fumigated diesel fuel or gasoline as supplementary fuels for a naturally-aspirated, four-stroke diesel engine with a swirl-combustion chamber. The supplementary diesel fuel or gasoline is introduced together with the aspirated air (fumigation) in various proportions with respect to the main diesel fuel, which is injected in the usual manner. The influence of fuel/feed ratios (supplementary or main feed), for a large range of loads, has been examined on fuel consumption, pressure diagrams, exhaust smokiness and exhaustgas emissions (nitrogen oxides, hydrocarbons and carbon monoxide). Knocking limits have been determined. The differences in the measured performance and exhaust-emission parameters from baseline engine operation, when using either supplementary diesel fuel or gasoline fumigated in the intake air, are determined and compared. Our study shows promise for this approach and indicates that above ˜60% of maximum load, there is high smoke reduction with only a slight change in specific fuel consumption, when using either one of the supplementary fumigated fuels. Examination of gaseous pollutant levels shows involved relations with respect to load and fuel proportions. Theoretical aspects of the supplementary fuel-mode (fumigation) of combustion are used to explain the observed engine behaviour.     

Study and design of a hybrid wind–diesel-compressed air energy storage system for remote areas

Remote areas around the world predominantly rely on diesel-powered generators for their electricity supply, a relatively expensive and inefficient technology that is responsible for the emission of 1.2 million tons of greenhouse gas (GHG) annually, only in Canada [1]. Wind–diesel hybrid systems (WDS) with various penetration rates have been experimented to reduce diesel consumption of the generators. After having experimented wind–diesel hybrid systems (WDS) that used various penetration rates, we turned our focus to that the re-engineering of existing diesel power plants can be achieved most efficiently, in terms of cost and diesel consumption, through the introduction of high penetration wind systems combined with compressed air energy storage (CAES). This article compares the available technical alternatives to supercharge the diesel that was used in this high penetration wind–diesel system with compressed air storage (WDCAS), in order to identify the one that optimizes its cost and performances. The technical characteristics and performances of the best candidate technology are subsequently assessed at different working regimes in order to evaluate the varying effects on the system. Finally, a specific WDCAS system with diesel engine downsizing is explored. This proposed design, that requires the repowering of existing facilities, leads to heightened diesel power output, increased engine lifetime and efficiency and to the reduction of fuel consumption and GHG emissions, in addition to savings on maintenance and replacement cost.     

Air cooling strategy of power battery based on minimum energy consumption

针对目前电动汽车动力电池风冷散热能耗高、散热滞后的问题,提出一种基于最小能耗的动力电池风冷控制策略,根据车载导航系统预报的工况信息预测动力电池的未来温升,在满足动力电池散热需求的前提下以风机能耗最少为目标,运用分段式动态规划算法确定风机在未来路段的开启时机与最优风速。以添加了坡度信息的ARB02、HWFET和UDDSHDV的组合工况为测试工况,对动力电池未来温升的精度进行了硬件在环试验,得出实际路况试验温度与预报工况试验温度的最大差值为0.3℃,最大偏差率为0.7%。与其他两种控制策略进行了Fluent仿真对比,结果表明基于最小能耗控制策略下动力电池的最高温度为39.87℃,最大温差为1.1℃;风机能耗是全程开启型控制策略的77.2%,是温度开关型控制策略的53.7%。该策略能有效控制动力电池的温度且风机能耗最小。     

Co-benefits from energy policies in China

The rapid growth in coal and oil consumption has led to increasing emissions of greenhouse gases as well as air pollutants in China. In response to this, the Chinese government has begun to formulate policies to retard the increasing use of energy consumption and to improve air quality. This paper attempts to quantify the co-benefits of reducing carbon dioxide emissions and improving air quality from policies that are originally formulated to improve energy efficiency and to abate emissions of air pollutants from energy use. The present authors have developed an integrated approach, combining an energy projection model, an emission estimation model, an air quality simulation model, and a health benefit evaluation model, to assess the co-benefits of two different sets of energy policies of China. The modeling results show that significant benefits, including 1469 million tonnes of reduced emissions of CO₂, 12–32% decline in air pollutant concentrations, and more than 100 billion US$ of health benefit, can be achieved around the year 2030 if aggressive energy policies are implemented. The analyses suggest that such energy policies could do a lot of benefit to the environment. Moreover, better industry structure and energy structure is essential for higher air quality.     

固体吸附除湿技术用于民用建筑中央空调系统的经济性分析

针对传统空调冷却除湿方式的高能耗,提出将固体吸附除湿技术应用于民用建筑中央空调系统,并对采用这种除湿方式的干式风机盘管加固体吸附独立除湿新风系统与传统的风机盘管加新风系统在运行能耗方面进行经济性实例分析,结果表明干式风机盘管加固体吸附独立除湿新风系统较传统风机盘管加新风系统其夏季空调工况每天减少约14W/m2,有效降低建筑能耗。     

Thermal storage in an air conditioning system with dual energy storage unit

在自行搭建的双蓄能实验平台上进行了制冷兼蓄热实验研究,对比了制冷兼蓄热模式和一般制冷模式,探讨了不同冷冻水流量和不同风机盘管风量对机组性能的影响.实验结果表明:蓄热对机组制冷端的影响很小,但是由于回收了大量的冷凝热,使得机组的综合能效比得到大幅提高,因此蓄热对空调节能具有较大作用.此外,在制冷兼蓄热模式下,冷冻水流量或风机盘管风量越大,机组的综合能效比越大,当风量为1033 m³/h,冷冻水流量为972 L/h时,机组综合能效比高达7.06.     

钻井平台温控风机研制及节能评价

根据目前钻井平台风机运行中存在的能源浪费的现状,提出了在保障安全前提下的风机温控方案,并开展设备研制,在钻井平台上成功应用。对温控风机系统的能耗监测表明该系统起到了预期的节能效果,为钻井平台技术节能提供了实施案例。     

Air pollutant control and strategy in coal-fired power industry for promotion of China’s emission reduction

Coal-fired power industry has always been the major power source in China. As coal-fired power industry consumes around a half of China’s coal production, it is always thought to be a big air pollutant emission source. As more and more strict legislations in coal-fired power industry have been issued by the government, the emission performance in coal-fired power industry has been drastically reduced recently. Based on a brief review of the development of emission control in China’s coal-fired power industry, the affecting mechanism among the development of installed capacities of emission control device, pollutant emission, and emission performances in coal-fired power industry is studied. According to a systematic study on the development of emissions of classified categories, the role of coal-fired power industry as a pollutant source is reevaluated. It is found that, coal-fired power industry has contributed the most to China’s emission reduction, and the barycenter of air pollutant emission has been transformed to other high energy consumption industries, like heat, iron/steel, and cement. Then some development strategies are suggested, such as maintaining the current emission standard in coal-fired power industry; expending the coal-fired power emission standards to categories of heat generation and supply, nonmetallic mineral production and ferrous metals smelting and processing; and controlling other heavy metal by consulting the method of Hg control.     

Neuro-optimal operation of a variable air volume HVAC&R system

Low operational efficiency especially under partial load conditions and poor control are some reasons for high energy consumption of heating, ventilation, air conditioning and refrigeration (HVAC&R) systems. To improve energy efficiency, HVAC&R systems should be efficiently operated to maintain a desired indoor environment under dynamic ambient and indoor conditions. This study proposes a neural network based optimal supervisory operation strategy to find the optimal set points for chilled water supply temperature, discharge air temperature and VAV system fan static pressure such that the indoor environment is maintained with the least chiller and fan energy consumption. To achieve this objective, a dynamic system model is developed first to simulate the system behavior under different control schemes and operating conditions. A multi-layer feed forward neural network is constructed and trained in unsupervised mode to minimize the cost function which is comprised of overall energy cost and penalty cost when one or more constraints are violated. After training, the network is implemented as a supervisory controller to compute the optimal settings for the system. Simulation results show that compared to the conventional night reset operation scheme, the optimal operation scheme saves around 10% energy under full load condition and 19% energy under partial load conditions.     

Biodiesel as alternative fuel: Experimental analysis and energetic evaluations

This paper presents the first results of an investigation carried out by the authors on the potentialities of biodiesel as an alternative fuel based on strategic considerations and field experiences in boilers and diesel engines.The operation of a biodiesel fuelled boiler has been checked for some months. The engines have been bench-tested and then installed on urban buses for normal operation. Distances, fuel consumption and emissions (CO₂, CO, HC and NO_X) have been monitored; in addition devices wear and tear, oil and air filters dirtiness and lubricant degradation have been checked.Further investigations have also been devoted to assess some environmental aspects of bio-diesel. In particular the benefit of biodiesel to the total net emission of CO₂ during the whole life cycle has been studied and the net energy requirement has been evaluated.Finally, the global environmental support to the production of biodiesel has been studied according to the emergy analysis.     

Optimization of diesel engine performances for a hybrid wind–diesel system with compressed air energy storage

Electricity supply in remote areas around the world is mostly guaranteed by diesel generators. This relatively inefficient and expensive method is responsible for 1.2 million tons of greenhouse gas (GHG) emission in Canada annually. Some low- and high-penetration wind-diesel hybrid systems (WDS) have been experimented in order to reduce the diesel consumption. We explore the re-engineering of current diesel power plants with the introduction of high-penetration wind systems together with compressed air energy storage (CAES). This is a viable alternative to major the overall percentage of renewable energy and reduce the cost of electricity. In this paper, we present the operative principle of this hybrid system, its economic benefits and advantages and we finally propose a numerical model of each of its components. Moreover, we are demonstrating the energy efficiency of the system, particularly in terms of the increase of the engine performance and the reduction of its fuel consumption illustrated and supported by a village in northern Quebec.     

Performance and emission characteristics of turpentine–diesel dual fuel engine and knock suppression using water diluents

In the present work, a normal diesel engine was modified to work in a dual fuel (DF) mode with turpentine and diesel as primary and pilot fuels, respectively. The resulting homogeneous mixture was compressed to a temperature below the self‐ignition point. The pilot fuel was injected through the standard injection system and initiated the combustion in the primary‐fuel air mixture. The primary fuel (turpentine) has supplied most of the heat energy. Usually, in all DF engines, low‐cetane fuels are preferred as a primary fuel. Therefore, at higher loads these fuels start knocking and deteriorating in performances. Usually, DF operators suppress the knock by adding more pilot‐fuel quantity. But in the present work, a minimum pilot‐fuel quantity was maintained constant throughout the test and a required quantity of diluent (water) was added into the combustion at the time of knocking. The advantages of this method of knock suppression are restoration of performance at full load, maintenance of the same pilot quantity through the load range and reduction in the fuel consumption at full load. From the results, it was found that all performance and emission parameters of turpentine, except volumetric efficiency, are better than those of diesel fuel. The emissions like CO, UBHC are higher than those of the diesel baseline (DBL) and around 40–45% reduction of smoke was observed at 100% of full load. The major pollutant of diesel engine, NO_x, was found to be equal to that of DBL. From the above experiment, it was proved that approximately 80% replacement of diesel with turpentine is quite possible. Copyright © 2006 John Wiley & Sons, Ltd.     

水平螺旋槽管油膜燃烧的实验研究

柴油水平螺旋槽管降膜蒸发机理可实现柴油的快速均匀蒸发,应用于燃烧室中可实现燃料与空气的迅速良好混合,有利于提高燃烧室燃烧效率并有效降低污染物排放。实验样机已实现工作过程的自动控制,体现出了优良的性能,与传统的基于转杯雾化机理燃烧室作了对比实验。并对实验结果进行了理论分析。研究结果表明,由于具有更均匀的混合气形成,柴油水平螺旋槽管降膜燃烧比传统燃烧方式具有更高的燃烧效率和更低的CO和NOx排放量。     

热管式定风量换气节能装置的设计及性能分析

主要研究了兼顾火电机组经济性与环保性的负荷优化分配算法,建立了考虑阀点效应的多目标负荷分配模型。应用自主编写的算法,获得了待决策的非支配解集合(Pareto front,PF),其中算法的核心操作是多目标融合、剔除同一层相近个体、保留不同层差异个体。给出了6台机组的负荷优化分配算例,仿真结果验证了模型的合理性,并表明方法可以进一步减少火电机组煤耗成本和污染物排放量。结合逼近理想解排序法(technique for order preference by similarity to an ideel solution,TOPSIS),讨论了不同目标权重下负荷分配方案的区别,证明了基于TOPSIS的多目标负荷分配方案的确定依赖于各自目标在决策中所占的重要程度。     

Available exhaust gas power in different configurations in a pellet stove plant

With a view to finding the best configuration for a small cogeneration system based on the pellet combustion process, exergetic analysis was applied to a small pellet stove. The evaluation focuses on fume exergetic content for power generation purposes. Preheated air, secondary air, fume recirculation and basis configurations were studied. Global exergetic calculation was developed at these configurations based on experimental correlations of energy and emissions. The influences of the pellet feeding rate, excess air, secondary air and fume recirculation were studied. The results for multiple configurations are discussed and the best one is presented. Results show that CO emissions have a major influence on fume exergetic content, although if emissions diminish only a slight thermomechanical exergetic efficiency increase is expected.