分户计量时散热器个体调节功能的实现方法

分析和研究了实现分户计量而采取的散热器个体调节的方法。     

地板采暖与采暖分户计量

论述了地板采暖在集中供暖分户计量中占有独特优势，天然适应单户计量、调节与控制。相比之下，散热器采暖却有其不足之处。分析认为，新型的地板采暖更具有发展前景，与分户计量供暖有深缠的纽带关系，是分户计量供暖的最佳选择形式。     

配合分户计量分户控制的换热站调节系统的节能改造

集中供热采用分户计量、分户控制后,换热站必须配合进行自动化调节,只有这样才能保证供热质量,也才能达到节能降耗、提高经济效益的目的。     

浅谈分户计量散热器采暖系统

介绍分户计量散热系统采暖的管道敷设、布置形式,新旧管道布置方式及其特点,采暖系统设计时需要注意的问题.     

分户计量改造后散热器流量对散热量影响变化分析

以烟台市三高校小区节能改造工程为例,阐述了既有住宅建筑供暖分户计量节能的改造过程,通过增加旁通管和温控阀,采暖系统由改造前的单管顺流式变为单管跨越式,随着进入散热器的流量发生变化,散热量有所增加。通过一个供暖期的运行证明,该系统能够有效地调节室内温度,节能效果达到预期的目标。     

供热分户计量在建筑节能中的重要性和可行性分析

中国的能源消费日趋紧张,节能工作迫在眉睫,供热系统分户热计量已经成为必然的趋势.本文对供热系统节能的必要性和可行性进行了分析,提出应大力实施供热分户计量以满足用户的自主温度需求,节省供热费用,提高城市供热质量,减少能源消耗量.     

漏汽率试验时调节级无温度测点的解决方法

针对部分汽轮机调节级后无蒸汽温度测点给高中压缸过桥汽封漏汽率计算带来困难这一问题,分析了调节级后焓误差对高中压缸过桥汽封漏汽率计算精度的影响,提出了调节级后焓的两种估算方法。实例计算表明,漏汽率计算时对中压缸排汽温度、再热蒸汽温度误差要求较高,对调节级后焓的误差要求不高,对高压缸压力级级组效率的误差要求也不高,在无调节级温度测点时,可用调节级焓降、高压缸压力级级组效率来估算调节级后焓,方法简单实用,可供兄弟电厂借鉴。     

汽轮机调节级变工况时焓降和反动度的计算

调节级焓降和反动度的计算是调节级变工况计算的基础和重要内容。介绍了汽轮机调节级变工况时焓降和反动度的计算方法,并以湖南某电厂N600-16.67-538/538-I型汽轮机为例,应用MATLAB语言编制计算软件进行了实例计算,根据计算结果绘制了调节级焓降和反动度的变化曲线。研究成果具有重要的理论意义和应用价值。     

具有负荷跟踪与补偿的水轮机调节方法及其微机实现

本文提出了一种基于频率及负荷扰动的水轮机调节方法。负荷跟踪与补偿的运用显著地改善了调节系统的动态及稳态性能。文中结合某水轮机调节系统对所论调节方法进行了仿真分析。     

采用个体进化能力实时评价和强制更新策略的换热网络优化方法

针对启发式方法在优化换热网络时出现个体进化停滞的现象,提出了一种采用个体进化能力实时评价和强制更新策略的进化算法。首先,建立个体进化能力评价机制,实时考察每个个体进化过程中的性能变化;其次,当个体进化能力退化时,建立强制更新策略,通过随机抽取当前结构中的换热单元,并给予其换热量以随机扰动,提高个体的结构变异能力,促进其整型变量的全局优化,改变个体原先的优化路径从而寻得更优的结构。将该算法应用于无分流换热网络实例中,取得了优于现有文献的结果,表明了该算法具有较强的全局搜索能力。     

单管顺流式系统热计量中风机盘管与散热器组合的探讨

将改良型风机盘管与散热器合理组合运用在常规单管顺流式住宅系统中,可以起到调控、计量作用,使得热计量相关系统改造简单、实用,又可节约大量的资金。     

新型钢制散热器翅片管的传热分析及优化

通过试验测得了翅片管的温度分布 ,得出这种新型散热器翅片管的自然对流换热规律。通过对试验数据的分析整理得到了肋壁平均换热系数的经验公式。分析了翅高比、翅片夹角对平均换热系数、平均辐射换热系数的影响。以金属热强度最大为目标函数 ,采用解多变量最优化问题的坐标轮换法得出了该形式翅片管的最佳结构尺寸。     

基于大数据户间传热对计量收费模型修正研究

采用现场实验测试方法,在典型用户的相邻住户入住率逐渐增加的过程中,对供暖期户间传热问题进行计算,并在运用相应大数据处理分析户间传热对分户热计量影响的基础上,分析供暖用户室内平均温度随时间的变化,并定量地分析户间传热量:邻户由于传热所得的热量约占其总耗热量的9.3%~47.2%。在热计量收费模型的有效可行的校正中,采用实际住户用热系数α和相邻用户间传热利用系数β。     

低温地板辐射供暖节能作用分析

低温地板辐射供暖地板与外围护结构内表面存在辐射换热，散热器供暖房间的散热器附近以及散热器上部热气流与外围护结构存在热流短路。文章在低温地板辐射供暖室比散热器供暖房间室内设计温度降低2℃的情况下，分别对三个典型地区这两种供暖方式在上述情况下造成的房间热负荷和供暖季平均耗热量进行计算。结果表明此条件下，低温地板辐射供暖房间的热负荷可降低10％～15％，节能率约为15％～20％。     

翅片式热管散热器自然对流换热特性分析与多目标结构优化

采用数值计算方法对一种应用于半导体制冷片热端散热的翅片式热管散热器进行模拟,探究自然对流条件下不同翅片参数对散热器换热特性的影响。结合多目标遗传算法(NSGA-Ⅱ),以影响散热器散热的两个主要参数——翅片表面传热系数和肋面效率为优化目标,对散热器整体做出综合优化,并对优化结果进行K均值聚类分析,提出了翅片端优化原则。结果表明,肋面效率对散热器性能的影响有限,提高表面传热系数可显著降低散热器总热阻;与未优化方案相比,所选优化方案可使基板热端面温度下降3.5K,散热器热阻降低18.22%。     

沟槽式散热器水冷服务器基板流动与散热性能的研究

如何在较低功耗下,使服务器基板CPU低于规定温度已成为数据中心冷却问题的关键。研究了沟槽式水冷散热器对服务器基板芯片的散热。首先,通过开展沟槽式散热器冷却一个模拟CPU服务器基板的实验,对散热器水冷却过程的流动特性和传热特性做了研究,并分别获得"压降-流量"和"进口水温-流量"的性能拟合公式。其次,开展采用集成式沟槽散热器冷却含多CPU服务器基板的实验研究,通过实验测试,改变冷却水的流量和入口温度,以期获取芯片温度为70和80℃时所提供的最小能耗。实验结果表明:进口温度为25℃时,芯片温度维持在80℃以下的最佳流量为0.8 L/min;使芯片温度稳定在70℃以下的最佳流量为1.0 L/min。     

Effect of electric field on heat transfer performance of automobile radiator at low frontal air velocity

The effect of electric field on the performance of automobile radiator is investigated in this work. In this experiment, a louvered fin and flat tube automobile radiator was mounted in a wind tunnel and there was heat exchange between a hot water stream circulating inside the tube and a cold air stream flowing through the external surface. The electric field was supplied on the airside of the heat exchanger and its supply voltage was adjusted from 0 kV to 12 kV.From the experiment, it was found that the unit with electric field pronounced better heat transfer rate, especially at low frontal velocity of air. The correlations for predicting the air-side heat transfer coefficient of the automobile radiator, with and without electric field, at low frontal air velocity were also developed and the predicted results agreed very well with the experimental data.     

Investigation of engines radiator heat recovery using different shapes of nanoparticles in H2O/(CH2OH)2 based nanofluids

In this paper, a flat tube of an engine radiator is modeled numerically for improving the cooling process or heat recovery of the engine using nanofluids. Two hydrogen based fluids (water (H₂O) and ethylene glycol or EG ((CH₂OH)₂) and four nanoparticles (CuO, TiO₂, Al₂O₃ and Fe₃O₄) in different shapes (Brick, Cylindrical, Platelet and Spherical) are considered for modeling the nanofluids in four different Reynolds numbers (500, 1000, 1500 and 2000). Hamilton correlation is used to calculate the thermal conductivity of nanofluids in different shapes of nanoparticles. Furthermore, the effect of nanoparticles volume fraction on the Nusselt number for all nanoparticle shapes is discussed in this study. Results show that EG-TiO₂ with platelet shape and larger volume fraction of nanoparticles has the best cooling performance for the engine among other modeled nanofluids.     

Feasibility study on novel hybrid ground coupled heat pump system with nocturnal cooling radiator for cooling load dominated buildings

When the ground coupled heat pump (GCHP) system is utilized for air conditioning in cooling load dominated buildings, the heat rejected into ground will accumulate around the ground heat exchangers (GHE) and results in system performance degradation. A novel hybrid ground coupled heat pump (HGCHP) system with nocturnal cooling radiator (NCR) works as supplemental heat rejecter is proposed in this paper to resolve this problem. The practical analytical model of NCR and novel HGCHP system are established. The computer program based on established model is developed to simulate the system operation performance. The novel HGCHP system is designed and simulated for a sample building located in Hong Kong, and a simple life cycle cost comparisons are carried out between this system and conventional GCHP system. The results indicate that it is feasible to use NCR serves as supplemental heat rejecter of the novel HGCHP system for cooling load dominated buildings even those located in humid subtropical climate areas. This novel HGCHP system provides a new valuable choice for air conditioning in cooling load dominated buildings, and it is especially suitable for buildings with limited surface land areas.