塑料管单效溴化锂吸收式制冷机系统设计及传热性能分析

溴化锂吸收式制冷机在工业中有着广泛的应用,但传热管腐蚀及其引起的冷量衰减一直以来是人们难以解决的问题,采用塑料传热管代替铜传热管来解决这个难题。进行了塑料换热装置及制冷机系统的结构设计,塑料换热装置的传热管采用聚四氟乙烯塑料管,传热管布置为阿基米德螺线状盘管。通过对塑料换热装置传热性能的分析,在溴化锂吸收式制冷机组中,吸收器使用聚四氟乙烯换热器代替传统的金属换热器具有最大的实用价值。     

塑料管单效溴化锂吸收式制冷机系统设计研究

进行溴化锂吸收式制冷机塑料换热装置及制冷机系统的结构设计,塑料换热装置的传热管采用聚四氟乙烯塑料管,传热管布置为阿基米德螺线状盘管,将实验传热系数与理论计算传热系数进行比较。比较结果表明：冷凝器、蒸发器实验传热系数低于理论计算值,吸收器的实验传热系数高于理论计算值。     

溴化锂吸收式冷暖水机组及投资决策分析

本文简述了溴化锂吸收式冷暖水机组的优点和目前我国国内溴冷机的生产、销售情况，运用了一系列专门的方法对溴冷机生产投资决策作了较为具体的可行性分析，并提出了应注意的有关问题。     

在溴化锂制冷机上应用板式换热器的可行性分析

在溴化锂制冷机上应用板式换热器的可行性分析陈亚平东南大学动力系溴化锂吸收式制冷机（简称溴冷机）具有节能、节电、无公害等优点，是取代氟利昂压缩式制冷机作为中央空调主机的最佳形式。目前溴冷机的结构形式都采用管壳式，大多用铜管作传热面。国外的先进技术也主要...     

用于太阳能空调的板型溴化锂吸收式制冷机

溴化锂吸收式制冷循环用于太阳能空调需要解决的主要问题是循环系统要适合集热器所能提供的热水温度范围，和提高溴冷机本身性能并降低其制造成本。板型(包括板壳式、板式、板翅式)换热器用于溴冷机具有效率高、结构紧凑、轻巧和成本较低等优点，已被本课题组研制的1台3kW板型单效溴冷机实验样机所证实。     

Numerical study on performance enhancement of latent heat storage unit

建立了考虑液态相变材料自然对流的壳管式相变蓄热单元的三维模型,数值分析了自然对流对相变蓄热过程的影响.对比研究了外侧强化传热管和双侧强化传热管对相变蓄热单元蓄热性能的强化效果.结果表明,液态相变材料的自然对流,会引起固-液界面分布不均匀现象,采用外翅片管可以有效削弱这一现象;采用外侧强化传热管和双侧强化传热管,都可以缩短相变材料完全熔化以及整个蓄热过程所需时间.与采用光管时相比,采用外侧强化传热管时,完全熔化时间减少了18.0%;采用双侧强化传热管时,完全熔化时间减少52.5%.可见,采用带有外翅片的强化传热管,不仅可以削弱自然对流引起的固-液界面不均匀性问题,而且可以强化相变蓄热单元的蓄热性能.     

风冷翅片管换热器传热特性研究

以铜铝复合翅片管为研究对象,结合翅片管换热器传热性能分析,给出其传热过程的物理模型.通过流固界面传热耦合,利用计算流体力学(CFD)软件进行模拟,对翅片管在不同风速、风温下的翅片管换热过程中温度场的分布进行数值模拟,得到翅片管的肋片效率,翅片管传热系数等一系列数值.并建立了试验台对其进行验证,结果表明翅片管能满足溴冷机在风冷条件下作为吸收器的散热要求.     

烧结环冷机余热电站运行特性研究

提高吨烧结矿余热发电量是环冷机余热电站优化设计与运行的目标。以唐钢炼铁厂北区烧结环冷机余热电站为例,通过建立以质能平衡为基础的热力计算模型和以发电净功率为目标函数的优化调度模型,研究了发电净功率随热废气温度和主蒸汽压力等参数的变化规律。统计分析了吨烧结矿发电运行指标的变化规律,确定了环冷机余热电站吨烧结矿发电指标的选择范围。其研究结果可为烧结环冷机余热电站运行参数调整和装机容量选择提供参考依据。     

热水余热制冷技术在塔河油田溴冷机中央空调上的应用

对塔河油田发电一厂余热锅炉高温段出水夏季热用户不足,存在热能浪费,难以寻找突破口以增加热用户等问题,通过应用热水余热利用技术,设计热水型溴化锂制冷机中央空调系统,取代已有直燃型溴冷机系统,节约了燃气费、电费等。在夏季热用户锐减形势下增加了热用户,确保余热锅炉平稳运行。完成了中石化"能效倍增计划"2014年立项项目之一。     

废热回收锅炉的改进

日本专利 公昭58—2 采用燃气透平高温排气来加热水,由此产生蒸汽驱动蒸汽透平的废热回收锅炉,由于其传热管的热膨胀会引起各种危害。这种废热回收系统见图1。 传热管有许多根,它们均被支撑板所支撑,汇总为一个接头,该接头接到圆形管座上(见图2,图3),以便穿过锅炉侧壁,即外部管道和传热管之间通过园形管座及接头进行连连(见图1)。由于传热管,接头及图形管座在发电厂运行时会被加热到几百度,传热管簇在长     

塑料管单效溴化锂吸收式制冷机理论研究

分析了塑料管单效溴化锂吸收式制冷机的理论循环，对塑料管单效溴化锂吸收式制冷机进行了热力计算和传热计算，为塑料管单效溴化锂吸收式制冷机的结构设计及实验研究提供理论依据。     

Experimental study of heat and mass transfer on an absorber with several enhancement tubes

An experimental study of the absorption process of water vapor into a lithium bromide solution was performed. For the purpose of the development of a high-performance absorption chiller/heater utilizing a lithium bromide solution as the working fluid, it is the most effective way to improve the performance of the absorber with the largest heat transfer area of the four heat exchangers. This paper considers a bare tube, bumping bare tube, floral tube, and twisted floral tube for the absorber of an absorption chiller/heater. The floral and twisted floral tubes have about 40% higher heat and mass transfer performance than the bare tube conventionally used in an absorber. Therefore, floral and twisted floral tubes are expected to realize high heat and mass transfer performance. © 1999 Scripta Technica, Heat Trans Asian Res, 28(8): 664–674, 1999     

Performance study of a solar-powered air-conditioning system

A solar-powered air-conditioning system was designed, installed and operated in Singapore. The system made use of 32 m² of heat-pipe collectors and a lithium bromide-water absorption chiller of 7 kW cooling capacity. The operation of the system was fully automated. The dynamics of its daily operation and its weekly energy performance is presented. The chiller operation is described by the relationship between its solar and auxiliary heater contributions. The performance of the system over a representative local insolation condition is compared with the reported performances of two systems operating in the USA.     

Optimum hot water temperature for absorption solar cooling

The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide-water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the performance of real chillers. This paper provides an explicit equation for the optimum temperature of vapor generation, in terms of only the external temperatures of the chiller. The additional data required are the four performance parameters of the chiller and essentially a modified stagnation temperature from the detailed model of the thermal collector operation. This paper presents and discusses the results for small capacity machines for air conditioning of homes and small buildings. The discussion highlights the influence of the relevant parameters.     

Design and test results of a low-capacity solar cooling system in Alicante (Spain)

Despite its attractiveness, solar cooling technology is still in an early stage of development. Most installations currently in operation show differences in the collector area per kilowatt of cooling capacity that cannot be explained only by project-specific circumstances. The purpose of this paper was twofold. First, to answer some questions that came up during the design process of the plant by using a TRNSYS system model and statistical tools. Second, to gain knowledge about the plant operation and validate the TRNSYS model through measured data. The system was equipped with a flat-plate collector field of 38.4 m². A lithium bromide-water single-effect absorption chiller (17.6 kW) was selected in order to provide chilled water to fan-coils. Performance data were registered at the solar plant working with a 1000-l heat storage tank and a required temperature of 80 °C to drive the absorption machine. An average of 29% of the solar energy incident on the solar collectors’ surface was transferred to the hot water storage. The registered average COP of the absorption chiller was 0.691. The performance data were compared with the values predicted by the TRNSYS plant model and a high level of agreement was obtained.     

Mathematical modelling of a LiBr–H2O absorption chiller including two-dimensional distributions of temperature and concentration fields for heat and mass exchangers

The paper presents the results of a theoretical analysis performed for a single-stage, water–lithium bromide absorption chiller at steady-state conditions. The model takes into consideration crosscurrent flow of fluids for heat and mass exchangers, two-dimensional distribution of temperature and concentration fields, local values of heat and mass transfer coefficients, thermal-parameter-dependent physical properties of working fluids and operation limits due to the danger of the LiBr–water hydrates and ice crystallisation. The main practical advantage of the model is the possibility to assess the influence of both the geometry parameters and operation parameters on thermal performance of the absorption chiller. The results derived from the implementation of the water vapour absorption process model for a horizontal tube absorber are consistent with the experimental measurements found in the literature.     

A comparison of solar absorption air conditioning systems

A computer simulation of solar powered absorption air conditioning systems is discussed. The results of simulations of various systems composed of conventional flat plate or evacuated tube collectors, wet or dry cooling towers, lithium bromide-water or aqua-ammonia working fluids and hot water, chilled water or refrigerant storage alternatives are obtained over a common operating cycle. Performance of the lithium bromide-water working fluid is shown to be superior to aqua-ammonia. Relative performance gains realized with the evacuated tube collector and relative performance losses associated with the dry cooling tower are presented. Chilled water storage is shown to be advantageous for an evacuated collector, dry cooling tower, lithium bromide-water system.     

从热工学角度探讨国产吸收式制冷机的发展方向

该文从热工学角度探讨了目前我国溴化锂吸收式制冷机整机热力循环及各热质交换设备性能、结构等方面存在的问题;在整机循环方面,指出实现各设备的合匹配、发展新的结构流程及增加新品种、新规格的机组为进一步的发展方向;在各设备性能、结构方面提出应加强吸收机理研究以及表面活化剂、高效强化管的应用研究。