Study of energy-efficient heat resistance and cooling technology for high temperature working face with multiple heat sources in deep mine

In the present research,we proposed a scheme to address the issues of severe heat damage,high energy consumption,low cooling system efficiency,and wastage of cold capacity in mines.To elucidate the seasonal variations of environmental temperature through field measurements,we selected a high-temperature working face in a deep mine as our engineering background.To enhance the heat damage control cability of the working face and minimize unnecessary cooling capac-ity loss,we introduced the multi-dimensional heat hazard prevention and control method called"Heat source barrier and cooling equipment".First,we utilize shotcrete and liquid nitrogen injection to eliminate the heat source and implemented pressure equalization ventilation to disrupt the heat transfer path,thereby creating a heat barrier.Second,we establish divi-sional prediction models for airflow temperature based on the variation patterns obtained through numerical simulation.Third,we devise the location and dynamic control strategy for the cooling equipment based on the prediction models.The results of field application show that the heat resistance and cooling linkage method comply with the safety requirement throughout the entire mining cycle while effectively reducing energy consumption.The ambient temperature is maintained below 30℃,resulting in the energy saving of 10%during the high-temperature period and over 50%during the low-temperature period.These findings serve as a valuable reference for managing heat damage in high-temperature working faces.

Reiner-Rivlin nanomaterial heat transfer over a rotating disk with distinct heat source and multiple slip effects

The thermodynamic features of the Reiner-Rivlin nanoliquid flow induced by a spinning disk are analyzed numerically.The non-homogeneous two-phase nanofluid model is considered to analyze the effect of nanoparticles on the thermodynamics of the Reiner-Rivlin nanomaterial,which also includes a temperature-dependent heat source(THS)and an exponential space-dependent heat source(ESHS).Further,the transfer of heat and mass is analyzed with velocity slip,volume fraction jump,and temperature jump boundary conditions.The finite difference method-based routine is used to solve the complicated differential equations formed after using the von-Karman similarity technique.Limiting cases of the present problem are found to be in good agreement with benchmarking studies.The relationship of the pertinent parameters with the heat and mass transport is scrutinized using correlation,which is further evaluated based on the probable error estimates.Multivariable models are fitted for the friction factor at the disk and heat transport,which accurately predict the dependent variables.The Reiner-Rivlin nanoliquid temperature is influenced comparatively more by the ESHS than by THS.The Nusselt number is decreased by the ESHS and THS,whereas the friction factor at the disk is predominantly decremented by the wall roughness aspect.The increment in the non-Newtonian characteristic of the liquid leads more fluid to drain away in the radial direction far from the disk compared with the fluid nearby the disk in the presence of the centrifugal force during rotation.The increased thermal and volume fraction slip lowers the nanoliquid temperature and nanoparticle volume fraction profiles.

Initiative Optimization Operation Strategy and Multi-objective Energy Management Method for Combined Cooling Heating and Power

This paper proposed an initiative optimization operation strategy and multi-objective energy management method for combined cooling heating and power U+0028 CCHP U+0029 with storage systems. Initially, the initiative optimization operation strategy of CCHP system in the cooling season, the heating season and the transition season was formulated. The energy management of CCHP system was optimized by the multi-objective optimization model with maximum daily energy efficiency, minimum daily carbon emissions and minimum daily operation cost based on the proposed initiative optimization operation strategy. Furthermore, the pareto optimal solution set was solved by using the niche particle swarm multi-objective optimization algorithm. Ultimately, the most satisfactory energy management scheme was obtained by using the technique for order preference by similarity to ideal solution U+0028 TOPSIS U+0029 method. A case study of CCHP system used in a hospital in the north of China validated the effectiveness of this method. The results showed that the satisfactory energy management scheme of CCHP system was obtained based on this initiative optimization operation strategy and multi-objective energy management method. The CCHP system has achieved better energy efficiency, environmental protection and economic benefits. © 2014 Chinese Association of Automation.

Technical and Economic Aspects and Experience from 6 Years of Operating the Technology Using the Waste Heat from the Exhaust Gases of Heat Sources and 3 Years of Operating a Heating Plant in an Autonomous, Island Regime

This article is focused on technical and economic evaluation of more than 6-years experiences of operating the Waste Heat Recovery technology—the manner and system of flue gas processing generated in the combustion process in heat & power plants, cogeneration units, etc., which burn the gaseous fuel, primarily natural gas, or methane, biogas, geothermal gas, or other gaseous mixtures containing hydrogen. The solution proposes a more effective and non-traditional use of gaseous fuel for heating, the flue gases of which are processed in order to extract additional utilisable heat, with potential elimination of CO2 from them. Deploying of the heating plant in an island regime (OFF-GRID) enables definition of the benefits brought by the 3 years of operational experience and presents visions for the future offering the possibility to utilise the support energy services at the municipal as well as regional level.

Design and Analysis of a Small Sewage Source Heat Pump Triple Supply System

Based on the characteristics of sewage from beauty salons,a simulation model of a small sewage source heat pump triple supply system that can be applied to such places is established to optimize the operating conditions of the system.The results show that with the increase of sewage temperature and flow,the performance of the system also increases.In summer conditions,the system provides cooling,recovers waste heat and condensed heat from sewage,with a COP value of 8.97;in winter conditions,the system heats and produces hot water,with a COP value of 2.44;in transitional seasons,only hot water is produced.The COP value is 2.75.Compared with the traditional systems which refers to the air source heat pump and hot water boiler system currently used in beauty salons,this system can save energy by 50.9%.

Transforming Waste Heat into“Renewable Heat”

Introduction:The current worldwide electric power&heat&cool production has a negative impact on the environment by emissions and enormous leaks of low-potential waste heat.Transformation of unused industrial low power heat into“renewable heat”useful to enhance the efficiency of the system is essential and actual innovation in the field of worldwide environmental protection.By introducing and defining the terminology of low-potential,“renewable”,“green heat”has created a new,parallel category of research in the energy sector.Traditional co-generation systems produce heat for space heating and hot water and generate electricity.Moving to tri-generation allows growing demand for air conditioning for homes,offices and commercial spaces such as server rooms and switchboards to be met simultaneously or on a seasonal basis.Tri-generation,or combined cooling,heat and power,is the process by which some of the heat produced by a co-generation plant is used to generate chilled water for air conditioning or refrigeration.Usually an absorption chiller is linked to the plant to provide this functionality.The technical solution is related to the new efficient manner and system of simultaneous generation of heat/cold from multiple heat sources,which has not yet been known,but in practice required.New system also enables advantageous utilization of solar power in supporting of the cooling output.The innovative system can be operated also within the existing central heating distribution systems.

计及热负荷柔性的户用氢能系统运行优化研究

针对风电/光伏出力的随机性和间歇性给户用氢能系统热电联供可靠性带来的挑战,提出基于热负荷柔性松弛运行约束的户用氢能系统热电联供优化策略。首先,搭建包含不同模块的户用氢能系统基础架构,并详细说明该系统的运行原理;其次,建立系统中关键环节的数学模型,确定电解槽平均氢/热比和燃料电池在不同温度下电/热比的范围;然后,为了兼顾用户的舒适度和热负荷的灵活性,根据热感觉平均标度预测指标对户用氢能系统的热负荷需求进行调整;最后,综合考虑储氢罐的容量限制、氢能设备的电/热功率和用户侧柔性热能需求等约束条件,以总投资成本最少和新能源弃电率最低为目标,建立户用氢能系统优化运行模型。仿真结果表明:引入柔性热负荷进行运行调节时,不仅增强了可再生能源的消纳能力,还显著降低了系统的运行成本。

Liquid Air Energy Storage for Decentralized Micro Energy Networks with Combined Cooling,Heating,Hot Water and Power Supply

Liquid air energy storage(LAES)has been regarded as a large-scale electrical storage technology.In this paper,we first investigate the performance of the current LAES(termed as a baseline LAES)over a far wider range of charging pressure(1 to 21 MPa).Our analyses show that the baseline LAES could achieve an electrical round trip efficiency(e RTE)above 60%at a high charging pressure of 19 MPa.The baseline LAES,however,produces a large amount of excess heat particularly at low charging pressures with the maximum occurred at~1 MPa.Hence,the performance of the baseline LAES,especially at low charging pressures,is underestimated by only considering electrical energy in all the previous research.The performance of the baseline LAES with excess heat is then evaluated which gives a high e RTE even at lower charging pressures;the local maximum of 62%is achieved at~4 MPa.As a result of the above,a hybrid LAES system is proposed to provide cooling,heating,hot water and power.To evaluate the performance of the hybrid LAES system,three performance indicators are considered:nominal-electrical round trip efficiency(ne RTE),primary energy savings and avoided carbon dioxide emissions.Our results show that the hybrid LAES can achieve a high ne RTE between 52%and 76%,with the maximum at~5 MPa.For a given size of hybrid LAES(1 MW×8 h),the primary energy savings and avoided carbon dioxide emissions are up to 12.1 MWh and 2.3 ton,respectively.These new findings suggest,for the first time,that small-scale LAES systems could be best operated at lower charging pressures and the technologies have a great potential for applications in local decentralized micro energy networks.

风电-火电-压缩空气储能综合能源系统运行特性研究

为提升电网消纳风电的能力,改善火电机组运行灵活性,本文基于压缩空气储能系统容量大、多能流耦合的特点提出了一种包含两台600 MW燃煤机组的风电-火电-压缩空气储能综合能源系统。首先通过构建系统热力学变工况模型,分析了关键参数对压缩空气储能系统性能的影响,然后以降低弃风率为目标,探究了综合能源系统在典型特征日的能流匹配和运行特性。结果表明,电能分配比由57.3%增加至76.0%时,储能系统输出热电比由0.84下降至0.30,对储能系统输出影响最为显著;典型特征日的仿真场景下,综合能源系统负荷调节能力强,能流匹配良好,弃风率仅为2.28%。通过上述分析,验证了所提出的系统具备可观的风电消纳潜力和运行灵活性。

低热-NaOH联合处理破解浓缩活性污泥释放碳源的试验研究

以低热-NaOH联合处理破解剩余活性污泥,考察NaOH投加量、加热温度、反应时间对污泥破解释放碳源的影响,通过总氮去除率分析污泥破解液代替生物脱氮外加碳源的效率,并研究该方法对污泥减量化的效果。结果表明:SCOD溶出率随NaOH投加量、加热温度和反应时间的增加而增大;当NaOH投加量为3.0g/L、加热温度为70℃、反应时间为24h时剩余活性污泥的破解效果最佳,污泥上清液中SCOD浓度可达1.829×10^(4)mg/L,总氮、氨氮、硝酸盐氮和总磷浓度分别达到943、419、487、204mg/L;污泥破解前后固体残渣中TSS含量由61.70 g/L下降至29.25g/L,VSS含量由31.95g/L下降至6.95g/L,生物减量化效果非常显著;污泥破解前后中值粒度D50分别为30.2、8.7μm,污泥破解过程中产生了大量的粒径为0.15μm左右的超细颗粒;扫描电镜结果显示污泥絮体和微生物细胞被破坏;在反硝化试验中,以最佳破解条件下释放的污泥破解液作为反硝化试验的补充碳源,结果显示COD利用率为83.4%,总氮的去除率为60.1%,脱氮的效果显著。低热-NaOH联合处理可在较低能耗下实现剩余活性污泥的碳源充分释放,且污泥减量化和资源化的效果优异,可为优化热碱法预处理剩余活性污泥提供依据。

土壤源热泵地埋管侧水系统优化运行研究

本文基于江苏无锡某典型厂房土壤源热泵空调项目的实测数据,以地源侧系统总能耗最低为目标,构建设备模型对地源水泵运行工况进行优化,并与两种传统控制策略的运行效果进行对比,据此提出进一步的优化建议。结果表明:基于负荷的优化控制策略,其节能效果要明显优于定频控制策略,冬夏季典型测试日平均节能率分别为28.33%和13.27%,相比于5℃温差变频策略节能了3.61%和2.21%。适当增大地埋管的埋管深度或管径,可以进一步提升该优化控制策略的节能效果。传统的定温差控制策略在负荷率大于60%时,可在5℃基础上将温差增加1~5℃以提升节能效果。

液态空气储能耦合综合能源系统热电联储联供优化配置研究

液态空气储能(LAES)在多能耦合的综合能源系统中极具应用前景,合理的储能容量配置更有利于综合能源系统低碳经济运行,但目前研究未充分考虑LAES热电联储联供强相关的特性和优势。因此,本文提出了一种LAES耦合综合能源系统的热电联储联供优化配置方法,针对综合能源系统的基本架构,构建了各组成单元的热电联储/供调度约束模型,并以设备初始投资成本、设备运维成本、购能成本、弃风弃光成本等为目标函数,考虑了系统能量平衡约束、设备容量约束、设备出力约束、外网交互功率约束以及储能约束,建立了相应的优化配置模型,并基于混合整数线性规划方法进行模型求解。以某实际园区为例,设置了5种场景进行优化结果对比分析,结果表明:考虑LAES热电联储联供特性的综合能源系统能实时有效地满足系统用能需求,同时能实现更好的经济效益和环境效益,相较于传统分供系统,系统总经济成本下降37.1%,实现碳减排71.50%,并在消纳可再生能源和减少弃光弃风方面更具潜力。本研究可为LAES耦合系统热电联储联供优化模型的有效性提供理论依据,有助于推动LAES在综合能源系统中的商业化应用。

热网蓄热特性及其对机组调峰能力的影响研究

为了提高热电联产机组调峰能力,利用热网蓄热实现机组的“热电解耦”。建立了某350 MW热电联产机组及其热网系统的动态仿真模型,研究了热网及其热用户在蓄/放热阶段的动态特性及环境温度对机组调峰能力的影响规律。结果表明:热用户滞后时间随着热用户与换热首站的距离的增加而增加,同时也受自身热负荷的直接影响和其余热用户热负荷的间接影响;热网相对蓄/放热功率在改变抽汽质量流量后先迅速变化再缓慢变化;热用户温度近似呈线性变化,其变化速率随着抽汽质量流量变化幅度的增大而增大,且开始变化时间也随之提前;机组最大调峰能力随着环境温度降低而略有增加,环境温度从0℃下降至-15℃时,机组调峰能力从23.8 MW增加至29.7 MW;增加蓄热时长,提高蓄热温度,降低放热温度均有利于提高机组调峰能力。

配置吸收式热泵的热电联产机组厂级智能运行优化

为提高配置吸收式热泵的热电联产机组的全厂运行经济性,基于案例电厂的运行历史数据,使用滑动窗口法进行数据预处理并提取稳态工况,建立配置吸收式热泵的热电联产机组煤耗预测数学模型。以全厂热电联产机组总煤耗最小为适应度函数,利用粒子群优化算法求解得出配置吸收式热泵的热电机组最佳背压和各台热电机组最佳抽汽量。基于以上研究设计了供热系统智能优化软件,实现供热系统在线监测与优化调节,对各供热单元分别提出优化指导,使机组运行经济性最佳,进而降低整体煤耗。计算结果表明:实行供热系统智能优化策略可为案例电厂供热系统平均每小时节省标准煤约1.81 t,节能效果显著。

计及网络动态特性的电-热互联系统仿射优化法

热网动态特性带来能量传输延时的同时,使得空间上的源荷不确定性对系统造成的影响存在时序上的先后差异,导致电-热互联系统日前调度转变为复杂的时空耦合问题。为此,该文提出一种计及网络动态特性的仿射优化法。首先,利用流量分段法与节点网络模型,构建计及能量传输延时且适用于环网的热网动态模型。在此基础上,利用仿射算法与牛顿-拉夫逊能流计算原理,通过线性化建模方式与模型凸化方法,构建仿射凸优化模型。其次,利用仿射优化法解决电-热互联系统不确定性优化调度问题,实现对源荷不确定性传播轨迹的跟踪及其影响的量化分析。最后,33节点电-热互联系统仿真算例证明,所提方法能够揭示网络动态特性下源荷不确定性影响机理,并获得具有低保守性、高经济性的调度方案。

基于ABAQUS的钛合金管板焊接过程模拟仿真

针对蒸汽发生单元钛合金管板焊接过程中焊接变形预测与控制问题,开展了焊接过程有限元仿真研究。基于顺序耦合的热弹塑性有限元法,采用ABAQUS对典型管板结构进行了不同焊接顺序下的焊接仿真分析,利用校核后的组合热源定义热流密度函数,计算得到焊接温度场、应力场及变形。结果显示,采用高斯热源与椭球体组合热源可以较为精确模拟熔池形貌,管板焊缝区域存在应力集中,且应力峰值位于管板被夹持区域,大小为631.2 MPa,超过材料屈服极限。单个环焊缝在不同路径下的应力分布因受到周围焊缝热输入的影响而出现复杂波动。采用从上至下的对称焊接顺序可以有效减小焊接变形量,最大变形量降幅可达24.3%,为后续工艺优化提供了参考依据。

太阳能空气源热泵联合运行测试与分析

【目的】为了研究太阳能空气源热泵相结合的采暖系统实际运行状况,对实际运行的太阳能空气源热泵联合运行系统进行了测试。【方法】对呼和浩特市使用太阳能空气源热泵系统的2座加油站进行现场测试数据采集和分析,测试数据包括在不同的环境下的耗电量、供热量、温度等。【结果】根据实际的测量结果可知,当环境温度相差不大时,不同年份对应月份的耗电量也相差不大;当环境温度为-20℃时,系统性能系数COP依然能达到2.4以上。随着环境温度的升高,性能系数COP逐渐增大。当环境温度为5℃时,系统性能系数COP达4.0以上。【结论】太阳能辅助加热有助于提高热泵系统整体性能,是一种适合低温环境下运行的空气源热泵采暖系统。

基于预测负荷的暖通空调系统优化调度

随着我国“双碳”目标的提出,公共建筑能耗低碳化成为重点研究领域,其中基于冷热负荷预测结果优化供能系统调度策略是实现“按需供能”的有效技术手段。针对公共建筑,基于热阻法构建了冷热负荷预测模型,根据负荷预测结果,采用改进粒子群优化(PSO)算法对复合冷热源供能系统的负载、水网供回水温度和流量、阀门开度以及泵组启用台数进行迭代寻优,以供能系统运行成本、机组寿命和环保性为优化目标提出全工况最佳运行策略。基于研究成果对某公共建筑冬季供热系统进行节能改造,可在满足建筑热负荷、平衡水力工况和延长机组运行寿命的同时,分别实现降低泵组功耗10.66%、系统运行成本21.52%。结果符合理论实际,证明了所提方法的可行性与有效性,为公共建筑的按需供热、节能运行提供了有效参考。

区域多热源联合供热系统热平衡及运行参数分析

以太原市供热现状为基础,分析多热源联合供热现状,探讨二次网分布式调峰锅炉与集中供热系统串、并联两种运行方式下的系统性能,建立热平衡方程和调节公式,并对相关运行参数进行求解。计算结果表明,相比串联连接,并联连接能耗更低。研究结果对区域多热源联合供热系统的设计及优化运行具有一定的指导价值。

利用冷凝侧回收热调控供液温度特性分析

针对某型液冷源供液温度波动较大以及冷凝侧热无利用排放问题,通过对系统工作原理和冷凝侧换热器结构等方面进行分析,提出可以利用冷凝侧回收热控制供液温度波动或实现供液温度的精确控制。建立了冷凝侧换热器的计算模型,并计算出系统冷凝侧空气进、出口温度、冷凝温度和冷却液出口温度等工作参数,以及在不同工况下的热回收量。结果表明,通过冷凝侧热回收的方式对液冷源供液温度进行调控,能够抑制供液温度波动,避免压缩机频繁启停,提高液冷源工作稳定性;冷凝侧热回收时,最大冷却液旁通流量为总流量的50%左右最为合适,并总结了系统制冷量与总热负荷能够实现平衡的工况区域。研究结论结果可为相关领域冷凝侧热利用提供参考。