空调冷源系统及其热回收系统的优化设计探讨

本文结合实际工程特点,对空调冷源系统进行了优化设计,同时对冷水机组热回收系统进行了优化设计及探讨。该工程的冷源具有大小主机搭配、可与风冷热泵机组互为备用的特点,较为经济节能。水泵与主机一对一连接,控制简单可靠。空调水系统设计为分区两管制系统,更加符合实际运行需求。冷水机组热回收系统采取热水罐串级连接,依靠热水罐的水温分层作用有效地实现了热水的梯级利用及顺序利用,同时综合考虑了热水管网的回水加热循环,充分地利用了冷水机组的冷凝热,更加节能,而且优化后的热水系统供水温度稳定,安全可靠。     

热回收机组在某酒店大温差空调系统中的应用

基于节能考虑,在某酒店项目的设计中应用了大温差空调系统,并根据热水用量配置空调热回收机组.介绍了空调热回收系统,说明了空调热回收机组优先旁流的技术特点.     

空调设计中的节能措施

通过对办公大楼空调系统的介绍,阐述了建筑中应用到的节能措施,包括加强围护结构保温隔热、排风热回收、选用高COP主机及合理匹配,达到降低空调能耗的目的。重点阐述了热回收系统的经济性。     

适配式热回收热泵空调系统的节能特性分析

在同时需要供暖、制冷的建筑物中，采用适配式热回收热泵空调有使空调机组的制冷、供暖时的总负荷平衡并尽可能地得到热回收，降低运行能耗。与传统的空调系统相比，适配式热回收热泵空调系统具有明显的节能效果。文章分析了适配式热回收热泵空调系统的工作原理和节能运行工况。     

某印刷有限公司空调与供热系统设计

介绍了某印刷有限公司的通风空调系统和热水系统工程概况和特点,总结了印刷车间和部份区域的通风空调、印刷设备的换热、空调热回收与热泵联合供热系统的形式,自动控制系统等方面的综合节能设计情况.     

北方地区地铁高架站热回收型多联机空调适用性分析

基于北方严寒和寒冷地区的地铁高架站,冬季车站站厅及设备管理用房人员房间有供热需求,同时车站设备用房存在大量散热需排除余热的情况,提出设置热回收型多联机,满足站内同一时间供冷和供热,相比与设备房间和人员管理房间分开独立设置空调,具有一定的节能优势。本文以某地铁高架站为例,从投资及运行能耗方面,分析探讨热回收型多联机空调在北方地区高架车站的适用性。     

佛山某商务中心综合楼空调系统设计

介绍了佛山某商务中心综合楼空调系统的设计。为倡导绿色建筑的设计理念,空调系统设计采用冷凝热回收技术、转轮热回收机组、板管蒸发式冷凝全热回收新风空调热泵机组、冷凝水回收等一系列节能措施,大大提高了系统能效比,降低了空调能耗,节能效果显著。     

乙二醇热回收系统节能初探

介绍了一种节能方式——乙二醇热回收系统在空调系统中的应用,阐述了此系统的工作和节能原理,并以某工程为例对此系统进行了节能和经济性分析,经分析后认为增设乙二醇热回收系统不但可节省运行费用,而且不需增加空调系统初投资,在空调节能方面具有广阔的应用前景。     

空调系统热回收影响因素及评价方法

定性分析空调系统热回收的影响因素，在此基础上引入一个新的热回收评价方法。此方法不仅考虑了空调系统热回收的能量，同时还考虑了系统附件配置的能耗。通过工程实例证明用此方法来评价空调系统采用热回收装置是合理可行的，同时对以后实际工程项目中热回收装置的选用有很好的指导意义。     

某会所的空调节能系统设计

本文介绍了某小区会所的空调节能系统设计,包括恒温泳池的三集一体系统、带热回收的变冷媒空调系统和新风全热回收系统。     

Impact of grain boundary junctions on grain growth in polycrystals with different grain sizes

Effect of finite mobility of triple and quadruple grain boundary junctions on grain growth is studied by numerical simulation. They retard the growth process and transform its kinetics from parabolic one into a sequence consisting of exponential, linear and parabolic steps. This relates even to polycrystals with large initial grain sizes. Such junctions can contribute to microstructure stabilization in nanomaterials.     

Three-dimensional virtual grain structure generation with grain size control

A three-dimensional (3D) controlled Poisson Voronoi tessellation (CPVT) model has been developed for generating 3D polycrystalline grain structures for micromechanics simulations. A virtual grain structure generated using the CPVT model has the property that its grain size distribution is statistically equivalent to the actual grain structure in term of the specified physical parameters: the mean grain size, a small grain size, a large grain size, and the percentage of grains within that range. Development of the CPVT model requires three steps: (1) Defining the regularity that specifies the uniformity of a tessellation, and deriving the control parameter based on the regularity, (2) establishing the mapping from the regularity to the distribution parameter of a one-parameter gamma distribution, (3) defining the mapping from the set of physical parameters to the distribution parameter. Relations between the regularity and distribution parameter, for a range of regularity values, are determined by a comprehensive set of statistical experiments, in which data fitting for the grain size distribution model is in each case obtained by an evolutionary optimisation algorithm. A software system (VGRAIN) has been developed for implementing the proposed three-dimensional CPVT model to generate the grain structure for crystal plasticity finite element (CPFE) analysis. To demonstrate the proposed scheme and the VGRAIN system, CPFE analyses of compression of micro-pillars are performed, and the effects of both regularity and grain size on the deformation are studied.     

The role of partial grain boundary dislocations in grain boundary sliding and coupled grain boundary motion

We study the process of grain boundary sliding through the motion of grain boundary dislocations, utilizing molecular dynamics and embedded atom method (EAM) interatomic potentials. For a Σ = 5 [001]{310} symmetrical tilt boundary in bcc Fe, the sliding process was found to occur through the nucleation and glide of partial grain boundary dislocations, with a secondary grain boundary structure playing an important role in the sliding process. While the homogeneous nucleation of these grain boundary dislocations requires shear strain levels higher than 7%, preexisting grain boundary dislocations are shown to glide at applied shear levels of 1.5%. The glide of the dislocations results in coupled motion of the boundary in the directions parallel and perpendicular to itself. Finally, interstitial impurities and vacancies were introduced in the grain boundary to study the effects on the sliding resistance of the boundary. While vacancies and H interstitials act as preferred nucleation sites, C interstitials do not. Both hydrogen and C interstitials stop dislocation glide whereas vacancies do not. A detailed study of the dynamic properties of these dislocations is also presented.     

Shape of grain size distributions during crystal grain nucleation in a-Si

The solid phase crystallization of chemical vapor deposited amorphous silicon films onto oxidized silicon wafers, induced by rapid thermal annealing has been extensively investigated. The morphological evolution of the amorphous towards the polycrystalline phase is investigated by transmission electron microscopy and it is interpreted in terms of a physical model containing few free parameters related to the thermodynamical properties of amorphous silicon and to the kinetic mechanisms of crystal grain growth at the early stages of transformation.     

The role of grain boundary energy in grain boundary complexion transitions

Recent findings about the role of the grain boundary energy in complexion transitions are reviewed. Grain boundary energy distributions are most commonly evaluated using measurements of grain boundary thermal grooves. The measurements demonstrate that when a stable high temperature complexion co-exists with a metastable low temperature complexion, the stable complexion has a lower energy. It has also been found that the changes in the grain boundary energy lead to changes in the grain boundary character distribution. Finally, recent experimental observations are consistent with the theoretical prediction that higher energy grain boundaries transform at lower temperatures than relatively lower energy grain boundaries. To better control microstructures developed through grain growth, it is necessary to learn more about the mechanism and kinetics of complexion transitions.     

Relation between grain boundary segregation and grain boundary character in FCC alloys

An analytical model of segregation at grain boundaries, which takes into account all five macroscopic parameters of grain boundary character, has been developed. The model is based on a combination of previous bond energy treatments of grain boundary energy and of segregation to free surfaces. It is tested by comparing its predictions against previous computations of segregation to symmetrical twist grain boundaries in simple fcc alloys obtained by Monte Carlo simulations in conjunction with embedded atom method potentials. The comparison shows good agreement with the previous computer simulations. Examples of model predictions in the case of asymmetric grain boundaries are also provided.