蒸发式冷凝器除垢、防垢方法研究

蒸发式冷凝器具有节水、节能、结构紧凑等特点而在工业制冷等领域得到了广泛应用。而水垢是降低蒸发式冷凝器换热效率和影响其平稳运行的最大天敌。为保证蒸发式冷凝器高效和无故障运行,提高蒸发式冷凝器热交换效率,本文从冷凝器换热盘管除垢清洗和循环冷却水水质管理防垢两个方面进行了研究和探索,分析了现有各种技术的原理和利弊,以期寻找到适用于相关企业实际工况的提高蒸发式冷凝器换热效率的有效途径。     

蒸发式冷凝器在向家坝水电站300拌和楼制冷系统的应用及节能分析

介绍不同类型冷凝器的特点,对向家坝水电站300拌和楼制冷系统分别使用水冷式冷凝器、蒸发式冷凝器进行设备选型,从设备购置成本、建安管道材料成本和运行期成本等方面进行经济性分析,结果显示蒸发式冷凝器比水冷式冷凝器更加节能。     

氨制冷装置用蒸发式冷凝器的实际能耗研究

理论上,蒸发式冷凝器的循环水量小于水冷式冷凝器的10％,因而采用蒸发式冷凝器更加节能。针对不同品牌的蒸发式冷凝器和水冷式冷凝器两种类型的典型产品,对能耗进行了理论计算、产品选型计算和现场测试比较分析。结果表明,蒸发式冷凝器单位排热量能耗的理论计算值、产品选型值和实际运行值差别不大。产品选型中,在相同的排热量下选用不同典型品牌的蒸发式冷凝器,能耗差异很大,如B品牌蒸发式冷凝器的平均能耗约为A品牌平均能耗的2倍。根据实际运行测试,三种典型品牌蒸发式冷凝器的平均能耗约为立式水冷式冷凝器系统的32％,约为卧式水冷式的47％。     

蒸发式冷凝器替代立式冷凝器的节能比较

本文对蒸发式冷凝器替代立式冷凝器后的安全运行和节能效果作了比较，阐明了蒸发式冷凝器的优越性。     

大连地区蒸发式冷凝器冬季不同运行方式的经济性研究

本文介绍了蒸发式冷凝器的结构及运行原理;以大连地区为例,提出了制冷系统蒸发式冷凝器在冬季运行时可以采用几种不同的运行方式,本文对这几种运行方式的耗能及投资进行经济性对比,在考虑系统对环境资源等因素的影响下,得出在冬季使用室内循环水箱水泵,其他季节采用自带循环水泵为蒸发式冷凝器提供循环水这一方案在大连地区制冷系统蒸发式冷凝器设计中占优。     

海底管道检测机器人智能控制器的研制

设计了以嵌入式PC104工控机为核心的海底管道检测机器人智能控制器,以嵌入式Linux操作系统作为该智能控制器的软件运行平台,根据控制任务的实时性和计算量的不同,开发的控制程序分别运行于系统实时内核和原Linux内核,满足了控制系统具有实时性、多任务并行处理等要求。详细介绍了管道检测机器人CAN通信应用层协议的定制规则,通过把报文的内容类别信息和节点信息纳入数据帧标识符来规定报文优先级,保证在多个数据帧同时竞争总线时,优先传送紧急程度高的报文。采用RS232-CAN协议转换器构建了具有检验智能控制器功能的试验平台,方便了控制程序的设计与验证。在实验室模拟油气管道台架上和工程现场的应用结果表明,该智能控制器实现了各种工况下的控制决策等功能,达到了设计要求,所设计的通信协议满足系统通讯要求。     

平行流冷凝器应用于食品冷藏柜的实验研究

新型单、双排平行流冷凝器应用于冷柜制冷系统中,并与原管片式冷凝器冷柜制冷系统进行对比实验分析。结果表明,应用单、双排平行流和管片式冷凝器的冷柜制冷系统分别在充灌量为550g、650g和800g时,周期内压缩机平均功耗最小,其中双排平行流冷凝器周期内压缩机平均功耗最小,单排平行流和管片式冷凝器相当。平行流冷凝器的空气侧换热性能明显优于管片式冷凝器。实验所用单、双排平行流冷凝器仅为管片式冷凝器换热体积的四分之一和二分之一,将平行流冷凝器应用于冷柜系统中将有利于解决冷柜冷凝器在恶劣环境下运行换热量不足的问题和降低成本费用。     

蒸发式冷凝器应用现状及存在问题探讨

本文简要介绍了蒸发式冷凝器结构形式和运行原理,总结了近些年来蒸发式冷凝器在国内的应用情况,针对蒸发式冷凝器在使用中存在的一些问题进行探讨并提出改进途径.     

新型套管蒸发式冷凝器的理论研究

提出一种新型套管蒸发式冷凝器，在蒸发式冷凝器的基础上在换热管中再加入一根内管，使得制冷剂可以在管的内部进行换热，提高冷凝器的传热系数，进而改善换热性能。针对此冷凝器介绍其结构形式和运行原理，并在相同状况下与蒸发式冷凝器进行数值计算比较，指出套管蒸发式冷凝器具有更好的换热性能。     

冷却水压差对离心式冷水机的影响分析

通过对离心式冷水机组冷凝器构造的分析,按管壳式热交换器Kern方程,由管程压降计算出冷却水流速,而后得出冷凝器的传热系数,进而算出冷凝器的热负荷和冷水机组的制冷量;建立冷却水压差和离心式冷水机组制冷量的关系,对冷水机组的设计和运行提供了一些参考。     

蒸发式冷凝器发展和应用

本文介绍了冷凝器型式特点及应用现状，比较了不同型式的冷凝器，着重阐述了蒸发式冷凝器的结构、原理及其优点，分析了蒸发式冷凝器的发展及应用现状，总结了蒸发式冷凝器使用中存在的问题并提出了解决问题的方法，展望了蒸发式冷凝器的发展方向和应用前景。     

A comprehensive design and rating study of evaporative coolers and condensers. Part II. Sensitivity analysis

Sensitivity analysis can be used to identify important model parameters, in particular, normalized sensitivity coefficients; by allowing a one-on-one comparison. Regarding design of evaporative coolers, the sensitivity analysis shows that all sensitivities are unaffected by varying the mass flow ratio and that outlet process fluid temperature is the most important factor. In rating evaporative coolers, effectiveness is found to be most sensitive to the process fluid flow rate. Also, the process fluid outlet temperature is most sensitive to the process fluid inlet temperature. For evaporative condensers, the normalized sensitivity coefficient values indicate that the condensing temperature is the most sensitive parameter and that these are not affected by the value of the mass flow ratio. For evaporative condenser design, it was seen that, for a 53% increase in the inlet relative humidity, the normalized sensitivity of the surface area increased 1.8 times in value and, for a 15 °C increase in the condenser temperature, the sensitivity increased by 3.5 times. The performance study of evaporative condensers show that, for a 72% increase in the inlet relative humidity, the normalized sensitivity coefficient for effectiveness increased 2.4 times and, for a 15 °C increase in the condenser temperature, it doubled in value.     

Mathematical model of heat and mass transfer processes in evaporative condensers

This study presents a new mathematical model of heat and mass transfer processes in evaporative condensers. The model consists of four ordinary differential equations with their boundary conditions and some associated algebraic equations. The model was formulated for steady-state heat and mass transfer conditions. A simulation computer program based on the model was written. It was devised for heat calculations in condensers built from bare tubes. The quality of the model was calculated by comparing the results obtained by running the program with experimental results achieved by other authors. The computed results show a good degree of conformity with experimental results. The differences are less than 20% (but in one case, 30%). The computer program may be used to determine heat performance of evaporative condensers of horizontal in-line and staggered bundle systems (if S_q > 2d_z).     

Investigation of heat, mass transfer and fluid flow characteristics in evaporative condensers

Heat and mass transfer and fluid flow characteristics in evaporative condensers is discussed. A complex pattern of water temperature and air enthalpy change was detected which depended upon elevation above the sump level. The results have indicated that the spray-filled space beneath the coil has a substantial effect of heat rejection in this type of apparatus. On the other hand, the effect of the upper spray nozzle zone is insignificant. It is possible to optimize the combination of various heat and mass transfer spaces, as well as the effect of extended surfaces and spray-filled spaces. Specifically, it will help to design better evaporative condensers with closely spaced staggered tubes, and to optimize the heat transfer and energy efficiency characteristics of such units.     

板式蒸发式冷凝器的性能实验

对板式蒸发式冷凝器进行的性能测试结果表明,在一定的结构形式下,存在最佳的入口风速和喷淋密度。同时根据实验结果拟合出板外水膜一空气间的传质系数关系式。另外,对基于同一蒸气压缩式制冷机组的水平管式和板式蒸发式冷凝器性能进行试验对比。结果表明,在测试条件下,采用板式蒸发式冷凝器的空调冷凝系统能效比提高了2．01％～3．1％,热流密度提高了20％～26％;与管式蒸发式冷凝器相比,板式蒸发式冷凝器换热器体积有所减小,而风机阻力和水泵功率略有增加。     

蒸发式冷凝器和水冷式冷凝器的能耗比较及经济性分析

本文分析了蒸发式冷凝器和水冷式冷凝器在同一冷凝温度下对应于相同冷凝负荷的能耗量。并用实例比较了蒸发式冷凝器、立式水冷式冷凝器和卧式水冷式冷凝器各自对应于900kW冷凝负荷的能耗量和初投资。比较的结果说明了蒸发式冷凝器比水冷式节能，也显示了卧式水冷式冷凝器不管在节省初投资和节能方面，均优于立式水冷式。     

蒸发式冷凝器水质管理

为保证蒸发式冷凝器高效和无故障运行,提高蒸发式冷凝器热交换效率,节约能源,对循环冷却水进行水质管理,对系统水进行除垢、缓蚀、杀菌灭藻处理是十分必要的。     

A comprehensive design and rating study of evaporative coolers and condensers. Part I. Performance evaluation

The mathematical models of evaporative fluid coolers and evaporative condensers are studied in detail to perform a comprehensive design and rating analysis. The mathematical models are validated using experimental as well as numerical data reported in the literature. These models are integrated with the fouling model presented in an earlier paper, using the experimental data on tube fouling. In this paper, we use the fouling model to investigate the risk based thermal performance of these evaporative heat exchangers. It is demonstrated that thermal effectiveness of the evaporative heat exchangers degrades significantly with time indicating that, for a low risk level (p=0.01), there is about 66.7% decrease in effectiveness for the given fouling model. Furthermore, it is noted that there is about 4.7% increase in outlet process fluid temperature of the evaporative fluid cooler. Also, a parametric study is performed to evaluate the effect of elevation and mass flow rate ratio on typical performance parameters such as effectiveness for rating calculations while surface area for design calculations.