Thermodynamic Simulation of CCP in Air-Cooled Heat Pump Unit with HFCs and CO₂Trans-Critical

The exergy analysis and finite time thermodynamic methods had been employed to analyze the compound condensation process (CCP). It was based on the air-cooling heat pump unit. The cooling capacity of the chiller unit is about 1 kW, and the work refrigerant is R22/R407C/R410A/CO2. The MATLAB/SIMULINK software was employed to build the simulation model. The thermodynamic simulation model is significant for the optimization of parameters of the unit, such as condensation and evaporation temperature and mass flow of the sanitary hot water and size of hot water storage tank. The COP of the CCP of R410A system is about 3% - 5% higher than the CCP of the R22 system, while CCP of the R407C system is a little lower than the CCP of R22 system. And the CCP of CO2 trans-critical system has advantage in the hot supply mode. The simulation method provided a theoretical reference for developing the production of CCP with substitute refrigerant R407C/R410A/CO2.

基于模糊理论的中央空调冷水机组节能控制方法

中央空调系统的能耗设备主要为制冷机组、水泵、风机。其中,制冷机组是整个系统中能耗最大的设备,因此,对制冷机组进行节能控制具有重要意义。但传统的恒温节能控制和时间节能控制方法往往无法根据环境温度的变化或负载变化进行智能调控,为此,设计基于模糊理论的中央空调冷水机组节能控制方法。设计二维结构的自适应模糊PID节能控制器,定义输入和输出变量的词集,建立模糊PID节能控制器的控制规则,对进入控制器的两个采样输入量实施模糊化处理,输出模糊化处理结果,以温度误差和误差变化作为输入变量,以调整中央空调冷水机组的输出量为最终输出量,对中央空调冷水机组进行节能控制。结果表明,该方法的温度误差仅为0.2℃,湿度误差仅为0.4%,投入后年总耗电量有效降低,具有较好的温度均匀控制效果,对于阶跃扰动响应的反应速度更快。

基于仿真对比的某办公建筑空调系统改造分析

对某办公建筑的老旧空调系统进行改造,比较了冷水机组与多联机2种改造方案,探讨了人员加班情况对系统选择的影响。首先,对建筑改造区域进行了负荷模拟,针对每种方案进行设备选型。然后,对2种方案供冷、供暖季的空调系统能耗进行了仿真和比对,多联机系统能耗更低,投资回收期仅4.6 a。最后,针对不同的加班模式和加班率进行了仿真分析,绘制了能耗-加班率曲线,发现多联机系统更适用于有人员加班情况出现的建筑。当独立办公室加班率为10%时,改造区域多联机系统的供冷季能耗比冷水机组系统低41.7%。

氯乙酸废蒸汽在溴化锂冷水机组中的应用

介绍了将氯乙酸生产过程中产生的废蒸汽作为溴化锂冷水机组的热源制取7℃水的改造措施,及改造后运行效果.

溴化锂吸收式冷水机组吸收器传热管腐蚀特性研究

本文采用挂样试验的方式,通过模拟溴化锂吸收式冷水机组吸收器与发生器中溴化锂溶液浓度45%与61%条件下,氧含量分别为0.5%、1%、5%、10%、20%、30%时对B30传热管的腐蚀情况,研究了B30传热管的有氧腐蚀特性,分析了溴化锂溶液浓度与氧含量的腐蚀影响因素与机理,结果表明当溴化锂溶液浓度为45%时,只要氧含量高于5%,B30传热管就会出现麻点状腐蚀,氧含量高于20%,B30传热管明显点蚀,深度达到0.5mm;当溴化锂溶液浓度为61%时,只有当氧含量达到30%,B30传热管才会出现明显的腐蚀麻坑。

风冷冷水机组隔振设计

风冷冷水机组一般安装在楼宇顶部,在运行时会产生振动,为达到行业规定的隔振效率,需要对机组进行隔振系统设计。文中介绍了隔振相关理论和减振器选用时的一般原则,并以公司某款风冷冷水机组为例,介绍了机组设计时减振器选择的基本步骤。

一种基于物联网的冷水机组数据采集监控系统

针对冷水机组的采集监控需求,设计了一套基于物联网的冷水机组数据采集监控系统。该系统通过专用物联网传输模块DTU(Data Transfer Unit)完成对冷水机组数据的实时采集和控制。采集到的冷水机组数据通过物联网数据传输单元DTU移动通信网,远程上传到云端控制中心,控制中心的软件实现了对冷水机组的数据采集监测和远程控制指令的下发。该系统实现了冷水机组的远程监测和控制,降低了系统运营成本,提高了系统工作效率和自动化水平。

基于优化BP神经网络的冷水机组故障监测研究

为提升冷水机组故障监测的准确性和实时性,结合粒子群优化算法并引入动量因子,提出一种基于优化BP神经网络的实时在线监测模型。主要介绍了BP神经网络的优化方式、冷水机组故障分析及参数选取、在线状态管理,通过Java编程语言和Encog神经网络库构建BP神经网络模型,并部署于某城市智慧运维平台,该模型有效提升了平台对冷水机组故障的监测能力。

风冷冷水机组管路共振分析及改善

某定频风冷冷水机组在半消声室进行整机噪声测试阶段,制冷模式下在机组左侧耳听有低频“嗡嗡声”,观察发现左系统储液罐与壳管的连接管出现振动“重影”现象,采集相关弯位的三向振动加速度响应,发现管路水平方向加速度响应为67.8 m/s2远超企标要求,首先识别管路的频响及相干函数获取了多个参考固有频率,初步判定管路在58 Hz处产生了共振,然后分别对原始管路及施加配重块的管路进行有限元模态分析获取其前四阶模态频率及振型,验证了配重块的移频效果,讨论了配重块位置对各阶模态频率的影响,最后识别施加配重块后的管路系统的频响函数,通过实验的方法确认加配重块后管路的一阶固有频率向低频移动了13.5 Hz,与仿真分析结果类似,最终测试了三种配重块布置方案下的管路振动加速度响应数据,对比确认了最终的减振方案采用方案2弯上侧一个配重块执行。

暖通空调设计研究——以某学院综合性图书馆工程为例

为优化综合性图书馆的暖通空调设计,以某学院图书馆工程为例,对其冷热源及供暖空调系统中模块化螺杆式冷水机组的应用及其优点展开探讨。分析了地下建筑的特点并介绍了HVA-SR热泵式热回收型溶液全空气机组在书库及档案库中的优点。阐述了工程中大空间区域空调系统的设计要点。研究显示,对于功能区域环境要求、空间结构及使用情况各不相同的此类建筑,除了要根据各区域使用环境要求设计系统外,还需综合考虑实际运行情况,合理划分系统、选用设备,从而达到节能、便于管理的目的。

Chiller faults detection and diagnosis with sensor network and adaptive 1D CNN

Computer-empowered detection of possible faults for Heating,Ventilation and Air-Conditioning(HVAC)subsystems,e.g.,chillers,is one of the most important applications in Artificial Intelligence(AI)integrated Internet of Things(IoT).The cyber-physical system greatly enhances the safety and security of the working facilities,reducing time,saving energy and protecting humans’health.Under the current trends of smart building design and energy management optimization,Automated Fault Detection and Diagnosis(AFDD)of chillers integrated with IoT is highly demanded.Recent studies show that standard machine learning techniques,such as Principal Component Analysis(PCA),Support Vector Machine(SVM)and tree-structure-based algorithms,are useful in capturing various chiller faults with high accuracy rates.With the fast development of deep learning technology,Convolutional Neural Networks(CNNs)have been widely and successfully applied to various fields.However,for chiller AFDD,few existing works are adopting CNN and its extensions in the feature extraction and classification processes.In this study,we propose to perform chiller FDD using a CNN-based approach.The proposed approach has two distinct advantages over existing machine learning-based chiller AFDD methods.First,the CNN-based approach does not require the feature selection/extraction process.Since CNN is reputable with its feature extraction capability,the feature extraction and classification processes are merged,leading to a more neat AFDD framework compared to traditional approaches.Second,the classification accuracy is significantly improved compared to traditional methods using the CNN-based approach.

Research and Demonstration of Direct Air-Cooling System for 600-MW Fossil-Fired Power Plants

Given the distribution feature of resources such as coal and water, the requirements for the development of Chinese power industry, and the fact of monopoly by foreign companies, it is very necessary and significant to independently research and develop air-cooling technologies. Through experimental research, simulative calculation, process and equipment development, field tests and a demonstration project, the design and operation technologies for air-cooling system are grasped and relevant key equipment is developed. The results of the demonstration project show that the technical indicators for the air-cooling system have met or exceeded the design requirements. Part of the research results have been incorporated into the relevant national design standards. The technologies developed have been applied to more than 23 sets of thermal power units of or above 600 MW in China.

超高效两级压缩水冷螺杆式冷水机组开发

针对两级压缩技术在中小容量冷水机组中鲜少应用的现状,本文设计了一种名义制冷量为615.48 kW的两级压缩水冷螺杆式冷水机组,采用新型转子型线和结构设计研制了两级变频螺杆制冷压缩机,并依据国家标准对开发的压缩机和冷水机组进行实验测试。结果表明:本文研发的两级变频螺杆制冷压缩机容积效率普遍高于96%,等熵效率最高达84.4%;冷水机组在出水温度为7℃的名义工况下COP达7.01,相比标准GB 19577—2015规定的一级能效水平高16.83%,部分负荷综合性能系数IPLV达到10.45,相比标准GB 19577—2015规定的一级能效水平高39.33%。两级压缩技术能够有效提升水冷螺杆式冷水机组的性能,与无中间冷却相比,中间冷却后冷水机组制冷量和COP分别提升11%和8%以上。

基于全生命周期成本的装配式高效制冷机房设计

为确保装配式高效制冷机房设计获得最优化的节能和经济效益,提出一种通过优化制冷机房布局和机组搭配方式来实现全生命周期成本最低的方法。将同一冷负荷下冷水机组台数、冷水机组摆放位置、冷却(冻)水泵摆放位置、冷水机组进出水口位置、设备进出水口与支管的连接角度以及机组与水泵对应关系作为全生命周期成本的影响因素,并以冷负荷1100RT为例对制冷机房布局与机组搭配进行优化分析。结果表明:在1100RT时,采用2台冷水机组,机组横侧摆放,机组冷冻端和冷却端进出水口位于机身两端,机组与水泵一一对应,冷冻和冷却水泵位于机组两侧,设备与管道成90°连接的方案最优;机组与水泵对应关系是影响全生命周期成本的主要因素,其次为设备进出水口与支管连接角度,其中60°连接虽然能够改善水力工况,但相对90°连接方式增加了35%的机房面积和初投资成本。

SPC and Kalman filter-based fault detection and diagnosis for an air-cooled chiller

Buildings worldwide account for nearly 40%of global energy consumption.The biggest energy consumer in buildings is the heating,ventilation and air conditioning(HVAC)systems.In HVAC systems,chillers account for a major portion of the energy consumption.Maintaining chillers in good conditions through early fault detection and diagnosis is thus a critical issue.In this paper,the fault detection and diagnosis for an air-cooled chiller with air coming from outside in variable flow rates is studied.The problem is difficult since the air-cooled chiller is operating under major uncertainties including the cooling load,and the air temperature and flow rate.A potential method to overcome the difficulty caused by the uncertainties is to perform fault detection and diagnosis based on a gray-box model with parameters regarded as constants.The method is developed and verified by us in another paper for a water-cooled chiller with the uncertainty of cooling load.The verification used a Kalman filter to predict parameters of a gray-box model and statistical process control(SPC)for measuring and analyzing their variations for fault detection and diagnosis.The gray-box model in the method,however,requires that the air temperature and flow rate be nearly constant.By introducing two new parameters and deleting data points with low air flow rate,the requirement can be satisfied and the method can then be applicable for an air-cooled chiller.The simulation results show that the method with the revised model and some data points dropped improved the fault detection and diagnosis(FDD)performance greatly.It can detect both sudden and gradual air-cooled chiller capacity degradation and sensor faults as well as their recoveries.

蒸汽型溴化锂机组代替水冷塔制取低温水技术的应用

针对空分预冷工序中传统的氮水预冷流程,结合项目现场水资源严重匮乏的实际情况,提出了蒸汽型溴化锂冷水机组代替水冷塔制取低温水的新流程,并对新流程和传统流程进行深入比较与分析。结果表明:新流程既能实现节能降耗的目的,又能增强装置的安全运行系数。

2022年国内外制冷空调行业市场分析

通过对2022年全球制冷空调市场统计数据的全面分析,详细阐述中国、美国、加拿大、日本等国家的制冷空调市场发展情况及变化趋势。2022年,在疫情反复冲击下,中国制冷空调行业砥砺前行,全年保持了质的有效提升和量的适度增长。2023年,中国经济将逐步回归到疫情前的常态运行,预计中国制冷空调行业总体将在平稳向好的基础上进一步提质增效。

雄安某社区中心空调冷源方案比选

结合项目当地能源价格,从投资费用、运行费用、维护费用等方面对雄安地区某社区中心的蓄冷空调、水冷螺杆式冷水机组、螺杆式风冷热泵、模块式风冷热泵、双热源多联机的空调冷源方案进行了对比,并结合项目用能特点,选择了双热源多联机冷源方案。

风冷热泵冷热水机组自调整模糊除霜控制研究

回顾了空气热源热泵除霜控制方法 ,提出了自调整模糊除霜控制的思想 ,介绍了系统的基本结构 ,输入论域的确定 ,输入量的模糊化和模糊推理方法。在高位机上实现了模糊除霜控制的仿真 ,并与实验数据进行了对比 ,表明自调整模糊除霜控制方法先进。

增大蒸发器面积对延缓空气源热泵冷热水机组结霜的实验与分析

实验研究了增大室外蒸发器面积对空气源热泵冷热水机组蒸发温度的影响,通过对我国可应用空气源热泵地区主要代表性城市气象资料的整理分析,统计计算了未增大蒸发器面积和蒸发器面积增大一倍时,空气源热泵冷热水机组在各地区的结霜时间。结果表明,当室外蒸发器面积增大一倍后,空气源热泵冷热水机组的蒸发温度平均提高了约2.5℃;在空气源热泵运行季节内,机组在不同地区的结霜时间减少了5.21%～82.96%。