Empirical investigation of the cooling performance of a new designed Trombe wall in combination with solar chimney and water spraying system

This paper presents an experimental study of a new designed Trombe wall in combination with solar chimney and water spraying system in a test room under Yazd(Iran) desert climate.The Trombe wall area is 50% of that of the southern wall of the building that occupies less space and reduces the implementation costs. The new design of the channel has caused the absorber to receive the solar radiation from three directions. Based on the results, the optimum mass flow rate and the nozzle diameter of the water spraying system has been obtained 10 l/h and 30 μm, respectively. The results indicate that the water spraying system decreases indoor temperature and increases indoor relative humidity by about 8 ℃ and 17%, respectively. The most effect of outdoor relative humidity variation is on indoor relative humidity, rather than indoor temperature. When outdoor temperature increases, both indoor relative humidity and the difference between indoor and outdoor relative humidity decreases. The results also showed that theTrombe wall; Solar chimney; Water spraying system(2) Prediction of energy performance of residential buildings:A genetic programming approach, P67-74, by Mauro Castelli,Leonardo Trujillo, Leonardo Vanneschi, Ale觢 Popovic Abstract: Energy consumption has long been emphasized as an important policy issue in today's economies. In particular, the energy efficiency of residential buildings is considered a top priority of a country's energy policy. The paper proposes a genetic programming-based framework for estimating the energy performance of residential buildings. The objective is to build a model able to predict the heating load and the cooling load of residential buildings. An accurate prediction of these parameters facilitates a better control of energy consumption and, moreover, it helps choosing the energy supplier that better fits the energy needs,which is considered an important issue in the deregulated energy market. The proposed framework blends a recently developed version of genetic programming with a local search method and linear scaling. The resulting system enables us to build a model that produces an accurate estimation of both considered parameters. Extensive simulations on 768 diverse residential buildings confirm the suitability of the proposed method in predicting heating load and cooling load. In particular, the proposed method is more accurate than the existing state-of-the-art techniques.

Neural Network Based Feasible Region Approximation Model for Optimal Operation of Integrated Electricity and Heating System

This paper proposes a neural network based feasible region approximation model of a district heating system(DHS),and it is intended to be used for optimal operation of integrated electricity and heating system(IEHS)considering privacy protection.In this model,a neural network is trained to approximate the feasible region of the DHS operation and then is reformulated as a set of mixed-integer linear constraints.Based on the received approximation models of DHSs and detailed electricity system model,the electricity operator conducts centralized optimization,and then sends specific heating generation plans back to corresponding heating operators.Furthermore,subsequent optimization is formulated for each DHS to obtain detailed operation strategy based on received heating generation plan.In this scheme,optimization of the IEHS could be achieved and privacy protection requirement is satisfied since the feasible region approximation model does not contain detailed system parameters.Case studies conducted on a small-scale system demonstrate accuracy of the proposed strategy and a large-scale system verify its application possibility.

Experimental Study on the Thermal Performances of a Tube-Type Indirect Evaporative Cooler

The so-called indirect evaporative cooling technology is widely used in air conditioning applications.The thermal characterization of tube-type indirect evaporative coolers,however,still presents challenges which need to be addressed to make this technology more reliable and easy to implement.This experimental study deals with the performances of a tube-type indirect evaporative cooler based on an aluminum tube with a 10 mm diameter.In particular,the required tests were carried out considering a range of dry-bulb temperatures between 16℃ and 18℃ and a temperature difference between the wet-bulb and dry-bulb temperature of 2℃∼4℃.The integrated convective heat transfer coefficient inside the tube in the drenching condition has been found to lie in the range between 36.10 and 437.4(W/(m^(2)⋅K)).

考虑变掺氧富氧燃烧与利用LNG冷能的LAES的综合能源系统低碳经济调度

为促进风电消纳,减少火电机组的碳排放,解决综合能源系统(Integrated Energy System,IES)低碳经济运行问题,文中引入变掺氧富氧燃烧技术对燃气机组进行改造,并结合利用液化天然气(Liquefied Natural Gas,LNG)冷能的液化空气储能(Liquid Air Energy Storage,LAES),提出了一种电热气冷IES低碳经济优化策略。首先,构建含变掺氧富氧燃烧燃气机组、利用LNG冷能的LAES、电转气(Power To Gas,P2G)设备、中央空调和溴化锂制冷机的IES架构,并建立各设备的数学模型;其次,引入阶梯式碳交易机制,建立了以系统运行成本最小为目标的电热气冷IES低碳经济调度模型;最后,采用MATLAB调用GUROBI求解器对多个场景进行求解,验证了文中提出的低碳经济优化调度策略可以提高系统的风电消纳、有效降低系统运行成本,实现碳减排。

A concept of capillary active,dynamic insulation integrated with heating,cooling and ventilation,air conditioning system

When a historic façade needs to be preserved or when the seismic considerations favor use of a concrete wall system and fire considerations limit exterior thermal insulation,one needs to use interior thermal insulation systems.Interior thermal insulation systems are less effective than the exterior systems and will not reduce the effect of thermal bridges.Yet they may be successfully used and,in many instances,are recommended as a complement to the exterior insulation.This paper presents one of these cases.It is focused on the most successful applications of capillary active,dynamic interior thermal insulation.This happens when such insulation is integrated with heating,cooling and ventilation,air conditioning(HVAC)system.Starting with a pioneering work of the Technical University in Dresden in development of capillary active interior insulations,we propose a next generation,namely,a bio-fiber thermal insulation.When completing the review,this paper proposes a concept of a joint research project to be undertaken by partners from the US(where improvement of indoor climate in exposed coastal areas is needed),China(indoor climate in non-air conditioned concrete buildings is an issue),and Germany(where the bio-fiber technology has been developed).

基于多变量相空间重构和径向基函数神经网络的综合能源系统电冷热超短期负荷预测

为解决能源危机问题,提高能源利用率,综合能源系统(integrated energy system,IES)成为发展创新型能源系统的重要方向。准确的多元负荷预测对IES的经济调度和优化运行有着重要的影响,而借助混沌理论能够进一步挖掘IES多元负荷潜在的耦合特性。提出了一种基于多变量相空间重构(multivariate phase space reconstruction,MPSR)和径向基函数神经网络(radial basis function neural network,RBFNN)相结合的IES超短期电冷热负荷预测模型。首先,分析了IES中能源子系统之间的耦合关系,运用Pearson相关性分析定量描述多元负荷和气象特征的相关性。然后,采用C-C法对时间序列进行MPSR以进一步挖掘电冷热负荷和气象特征在时间上的耦合特性。最后,利用RBFNN模型对电冷热负荷间耦合关系进行学习并预测。实验结果表明,所提方法有效挖掘并学习电冷热负荷在时间上的耦合特性,且在不同样本容量下具有良好且稳定的预测效果。

基于微流道冷却的水卡式量热计结构优化与试验分析

高声速飞行器再入过程中面临严峻的气动加热环境,最高气流温度可达上万摄氏度,常用量热计在如此高的气流温度下,缺乏良好的热流测试性能和热负荷生存能力。为解决地面试验中高超声速飞行器模型表面高热流的连续、精准测量难题,研发了一种基于微流道冷却的新型水卡式量热计,其内部微型流道结构采用3D打印技术构建。通过数值仿真,确定了新型水卡式量热计的微流道尺寸与布局,与同一冷壁热流的传统水卡式量热计相比,其核心区域温升降低近50%,验证了微流道水卡式量热计在极端热环境下的测试能力和生存能力。电弧加热射流试验结果表明:微流道水卡式量热计可以同步测量压力、温度、热流数据,实现了高温流场参数的集成化辨识,并具有良好动态响应特性;最大热流测量值超过18 MW/m^(2),测量绝对偏差和平均偏差分别控制在3.44%与±1.72%以内。

增程式电动汽车动力系统一体化冷却传热分析

以一款增程式轻型卡车为研究对象,对增程式动力系统的发动机和电机采用一体化冷却系统设计。在预设的运行工况,通过试验测试,计算出工况点增程器和电驱系统的散热需求,对冷却液和冷却水泵进行选型匹配。结合试验测试建立了增程器和电驱系统冷却回路一维仿真模型,对比分析了电驱系统冷却管道串联与并联的冷却效果与能耗情况,验证了驱动电机冷却液帮助发动机冷起动的可行性。研究结果表明:通过试验测量散热量选择到的电子水泵,能更加高效准确地控制冷却液流量,冷却效果更好。冷却系统一维仿真分析中能从温升曲线直观看到并联冷却管路冷却效果更好,并联管路中的电磁阀根据工况不同控制开口大小,比串联管路统一控制冷却液流量冷却更高效。并联冷却管路中驱动电机冷却时快速产生热量,在与发动机冷起动时进行热交互可以帮助发动机快速暖机,改善发动机冷起动排放差、动力弱的情况。

火电厂源侧综合能源系统集成及性能评估研究

本文建立了以火电厂为核心,消纳可再生能源并提供冷热电汽综合能源服务的一套能源系统,通过对整体系统及关键子系统热力性能分析,验证了提出模型和方法的有效性。并研究了一些关键运行参数对系统综合性能的影响,验证了提出模型和方法的有效性和优越性。结果表明:通过改变火电厂的源侧参数,可以提高综合能源系统荷侧的输出量;且生物质转化气对汽轮机发电功率的影响最大。热泵系统的负荷随着进入系统中的给水流量的增大而增大,利用汽轮机中的部分抽汽来驱动热泵系统,虽然发电功率下降了10.88%,但是却为用户提供了16.8MW的热负荷和16.2MW的冷负荷以及27.78t/h的蒸汽量。

Thermo-Flow Performances for the Main-Auxiliary Integrated Natural Draft Dry Cooling System

Recently,natural draft dry cooling system with the main-auxiliary integrated air-cooled heat exchangers in the up and lower layers,has drawn attention to the electric power industry.This research firstly develops two physical models for the integrated cooling system,namely Case A and Case B.In Case A,the main air-cooled heat exchanger is arranged in the upper layer and the auxiliary air-cooled heat exchanger arranged in the lower layer,while in Case B,the two heat exchanger systems are arranged in the opposite way.And then,directing at the engineering TMCR and TRL 1 working conditions,the unit-local-overall thermo-flow characteristics of Case A and Case B are obtained and compared by numerical simulation.The findings show that,for the auxiliary air-cooled exchanger,Case A has obviously higher cooling performances than Case B,with the difference varying from 5.46%to 7.55%.Whereas,for the main air-cooled exchanger,Case B shows the recovered cooling performances,with the difference changing from 1.15%to 2.99%.Case A is preferably recommended to the engineering application in consideration of more strict cooling demand of the auxiliary cooling system.Conclusively,this research will provide some theoretical guidelines for the design and construction of the main-auxiliary integrated natural draft dry cooling system.

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。

染整热定形机出布冷却装置研究

阐述了染整热定形机出布冷却的重要性,介绍了定形机常规的冷却装置及其存在的不足,分析了改进后的冷却装置的研究现状,并提出了需要优化的问题,展望了定形机出布冷却研究方向。

含碳捕集及电制热负荷的综合能源系统优化调度

调节控制负荷侧协同消纳新能源是新型电力系统下的关键技术之一。考虑到热电联产机组的以热定电工作方式,加剧了热电耦合效应,提出了利用碳捕集技术辅之电制热负荷为热电联产机组提供辅热的优化调度策略。首先,分析多元系统电力电量平衡关系,建立碳捕集设备和热电联产的运行特性模型;其次,考虑碳捕集和电制热负荷无极调节优势及运行边界,建立了考虑弃风成本、碳交易成本的含CHP-CCS的综合能源系统优化调度模型;最后,以中国北方某城市冬季供暖期为例,利用CPLEX进行数值分析。仿真结果表明,该方法能够提升系统经济性和新能源消纳率,同时达到了减少碳排放量的目的。

考虑多能耦合共享储能的微网多智能体混合博弈协调优化

冷热电耦合的共享储能可以更显著地提高微网多种能源的利用效率与消纳水平。然而,多能耦合的共享储能进一步增加了多微网之间协调运行的难度,故而提出了一种考虑多能耦合共享储能的微网多智能体混合博弈协调优化模型。首先,围绕多能耦合共享储能进行建模,从冷、热、电3个维度构建元件的运行模型。其次,提出了一种计及多能耦合共享储能协作的微网混合博弈双层协调调度模型。上层部分为基于主从博弈的微网运营商日内电价优化模型,以微网运营商的日内收益最大化为目标,综合考虑电价上下限约束和购售电价平均值约束,为下层协作运行提供响应电价;下层部分为基于合作博弈的微网间协作运行策略模型,以产消者和共享储能电站的合作成本为目标,综合考虑机组出力上下限约束和功率平衡约束,为上层反馈合作成本用于指导电价优化调整。然后,在混合博弈模型求解时,以电价变动率为收敛判据,同时采用二分法处理电价约束以加速模型求解。最后,采用多智能体协调优化的微网系统验证了所提方法的有效性。

计及风光储的冷热电联产综合能源系统低碳经济优化

为解决能源危机,中国大力发展综合能源系统,以期进行多能协同互济,实现节能降碳。主要研究计及风光储的冷热电联供系统多目标优化调度问题。首先,从经济和碳排放2个不同的角度出发,建立经济目标函数和环境目标函数,构造考虑风光储的冷热电联供系统多目标优化配置模型以及相应的约束条件;然后,提出增强的非支配排序遗传算法Ⅱ(non-dominated sorting genetic algorithmⅡ,NSGA-Ⅱ),通过引入支配强度和方差因子,提高算法求解效率和求解精度;最后,以辽西某地正在运行的冷热电联供系统为例进行仿真分析,验证本文所提模型和方法的有效性。

某高频段瓦式相控阵天线的热设计与试验分析

随着通信技术的快速发展,瓦式相控阵天线以其小型化、高性能、高集成的特点,已逐渐成为有源相控阵天线发展的新趋势。但随着频段及集成度的不断提高,多功能集成芯片的热流密度也越来越大,随之带来的散热问题也更为突出。针对某高频段瓦式相控阵天线的热设计要求,提出一种强迫风冷条件下“散热风道+扁平热管”的低成本散热方案,通过数值仿真验证阵面发热器件可控温度及多功能集成芯片温度一致性,搭建热测试平台进行热测试,对测试点实测温度与仿真温度进行对比分析。数值仿真和试验结果表明:所设计的热控结构能够满足发热器件的壳温要求以及多功能集成芯片的温度一致性要求,进一步验证了该散热方案的合理性,可为后续同类瓦式相控阵天线的热设计提供一定的参考。

基于多能源需求响应的综合能源系统动态优化控制研究

需求响应(Demand Response,DR)是需求侧参与电网灵活互动的重要途径,其在能源互联网中衍生为综合需求响应(Integrated Demand Response,IDR),利用冷、热、电、气等不同形式能源间的耦合互补关系,在需求侧进行多能源协同优化。文中基于综合能源系统(Integrated Energy System,IES)框架结构和IDR的基本理论,提出考虑多能源需求响应下的综合能源系统动态优化控制方法。依据电力需求和价格弹性理论,综合考虑了能源价格对电力、热力、天然气等能源消耗量的影响,构建了多元化用能价格需求响应模型;以经济和环境成本最小为目标,建立了基于DR机制的IES多目标动态运行优化模型,并采用基于超平面投影方法的改进非劣性遗传算法(HP-NSGA-Ⅱ)进行求解,以典型园区为例进行实例仿真分析,验证了多能源需求响应对促进综合能源系统优化运行的有效性。

考虑冷热电三联供系统耦合特性的区域综合能源系统运行优化

为了加快实现双碳目标,提高能源利用效率、减少碳排放量,通过选取关键供能设备冷热电三联供系统(combined cooling heating and power system,CCHP)构建了综合能源系统模型,并利用改进的二代非支配排序遗传算法(non-dominated sorting genetic algorithm-Ⅱ,NSGA-Ⅱ)研究了引入该设备后园区整体运行方式和运作效率的改变。结果表明:CCHP设备可通过其强耦合特性实现供能侧设备的多能互补和能量梯级利用;可见通过引入CCHP过后,可大大提高综合能源系统的运行效率,在减少运行成本的同时相对控制碳排放量的释放,提高系统总体效益。

高速飞行器减阻降热研究进展

降低飞行阻力、探索更高效的热防护系统是研发高速飞行器过程中至关重要的课题.目前,国内外学者在飞行器减阻降热的机理及应用技术方面进行了大量研究,取得了丰富的成果.本文系统地梳理了在高速飞行器减阻降热领域的研究进展,阐述了主动热防护机理的研究结果,介绍了应用于高速飞行器的前沿减阻降热技术,并简述了基于余热利用的整体热防护系统的发展情况.基于对研究现状的分析,归纳总结了高速飞行器减阻降热技术的发展趋势与实际研究需求;最后针对这些实际研究需求,提出了一些研究思路上的建议.