热管在废气直接驱动的溴化锂制冷机中的应用

本文主要就利用废气、废热直接来驱动溴化锂制冷机进行研究和探讨。     

太阳能制冷与供暖系统的设计与比较

根据上海的气候条件，以上海地区某写字楼为对象，提出4种太阳能驱动的溴化锂吸收式与电动蒸汽压缩式热泵联合制冷与供暖系统。这4种系统分别由热管式真空管集热器或抛物面槽形聚光集热器，单效或双效溴化锂吸收式制冷机，以及风冷热泵或水源热泵构成。分析比较这4种系统的节能型和经济性的结果表明，采用抛物面槽形聚光集热器＋双效溴化锂吸收式制冷机＋风冷热泵组成的系统，同时具备较好的节能性与经济性，一次能源利用率可降低约50％。     

溴化锂吸收式制冷机的应用分析

概述了溴化锂吸收式制冷的原理，分析了溴化锂吸收式制冷机的综合效益及其一次能源利用率，以热电厂热电冷三联供系统为例分析了溴化锂吸收式制冷机的节能效益，并指出了溴化锂吸收式制冷机在工程应用中应注意的问题。     

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。     

溴化锂吸收式制冷机动态特性仿真系统

设计并完成了溴化锂吸收式制冷机动态特性的测量试验，通过试验，对溴化锂吸收式制冷机的动态特性进行了分析，求出了被控对象的传递函数，建立了动态数学模型。在此基础上，设计了溴化锂吸收式制冷机动态特性的仿真系统。并对控制器的控制参数进行整定，得到了最佳控制结果。     

热管技术在电石工业开式炉中的应用

热管在废热回收方面具有明显的经济价值。本文着重介绍热管在开式电炉记气废热回收上的应用，为热管在电石行为的广泛应用提供一些经验。     

热管换热器在水泥回转窑上的应用

热管在废热回收方面具有明显的经济价值。本文着重介绍热管在水泥回转窑窑尾烟气废热回收上的应用，为热管在水泥窑上的广泛使用提供一些经验。     

溴化锂吸收式制冷机与蒸汽压缩式制冷机的能耗比较

本文对溴化锂吸收式制冷机与蒸汽压缩式制冷机的能耗进行了比较研究,认为溴化锂吸收式制冷机节电不节能,而溴化锂吸收式制冷机与离心式制冷机联合运行,既可缓解供电紧张,又可提高能量利用效率,应予以充分重视。     

溴化锂水溶液热物性计算可视化程序

根据国内外有关溴化锂水溶液的热物理性数据,编制了溴化锂水溶液的热物性计算程序软件,与实验数据对比显示较好的吻合性,采用混合编程的方法,实现了计算程序的可视化,适用于化锂吸收式制冷的性能分析与计算,以及对溴化锂吸收式制冷机的在线检测。     

二泵系统新流程溴化锂制冷机的研制

一、概述”近年来溴化锂吸收式制冷机在我国取得了迅速发展，这是基于溴化锂吸收式制冷机是一种以低品位热能为动力的制冷设备，特别在我国目前电力供应比较紧张的情况下，具有节电和节能的显著效果，同时为了保护地球臭氧层，蒙特利尔协议书对氟里昂的应用作了限制，而溴化锂对环境无公害，不会破坏大气臭氧层，因此，溴化锂吸收式制冷机受到特别重视。但是纵观我国溴化锂吸收式制冷机的现状，大多采用传统的三泵系统，并联流程，不仅机组装机功率偏大，而且在流程设计上存在着容易产生“结晶”现象的隐患，为此，我们在消化吸收国内外先进…     

充气热管空气预热器的设计分析及应用

对充气热管空气预热器的结构进行分析和应用介绍,采用平界面模型,确定充气热管冷却段的有效长度。在原始参数相同的条件下,对充气和不充气的热管换热器进行试验,分析热管最低控制工作温度、排烟温度和换热面积之间的差异。工业试验和实际应用结果表明：在变工况和高硫煤(5％-7％)的条件下采用充气热管空气预热器具有十分优良的防腐蚀和防积灰的性能。     

浅谈循环流化床锅炉水平烟道热管式省煤器应用

将省煤器安装在锅炉尾部,可解决排烟温度过高的问题。热管技术在余热回收项目的应用是目前比较成熟的方案,通过现场勘察和计算,使用热管式省煤器,能够解决排烟温度过高的问题,同时也可保证锅炉安全运行。     

浅谈循环流化床锅炉水平烟道热管式省煤器应用

将省煤器安装在锅炉尾部，可解决排烟温度过高的问题。热管技术在余热回收项目的应用是目前比较成熟的方案，通过现场勘察和计算，使用热管式省煤器，能够解决排烟温度过高的问题，同时也可保证锅炉安全运行。     

异型高温热管翅的实验研究

对一结构特殊、长为6cm的异型高温热管翅在不同的工况下进行实验研究。通过改变蒸发段长度、绝热段长度、冷凝段长度、散热条件及其放置位置,观察其壁面温度分布情况,掌握其最佳工作状况。结果表明,当热管翅水平放置且在自然环境下散热时,不凝性气体的影响使热管翅冷凝段末端温度偏低;当蒸发段长度太长时,热管翅蒸发段会出现过热点,而冷凝段出现温度回升现象;若使热管翅的冷凝段在有限空间散热,则温度回升现象消失;当热管翅倾斜放置时,热管翅工作性能处于最佳状态。     

Performance Analysis and Optimization of a Single-Barrier Solid-State Thermionic Refrigerator With External Heat Transfer

A model of a single-barrier solid-state thermionic refrigerator with external heat transfer is established in this paper. The performance of the refrigerator is analyzed and optimized by using the combination of finite-time thermodynamics and nonequilibrium thermodynamics. The general expressions for cooling load and coefficient of performance (COP) of the refrigerator are derived. The optimum regions of cooling load and COP are obtained and the effects of the heat reservoir temperature and thermal conductance of the barrier material on the performance of the refrigerator are analyzed by detailed numerical examples. The results obtained are compared with those obtained by using traditional analysis without considering external heat transfer. For the fixed total heat transfer surface area of two heat exchangers, the ratios of the heat transfer surface area of the hot-side heat exchanger to the total heat transfer surface area of the heat exchangers are optimized for maximizing the cooling load and COP of the refrigerator, respectively. The effects of the total heat transfer surface area and the applied voltage on the optimum performance of the refrigerator are analyzed. The results obtained herein may provide some theoretical guidelines for the design and application of practical solid-state thermionic refrigerators.     

Comparisons of thermal performance and pressure drop of counterflow and parallel-flow heat-pipe heat exchangers with aligned/staggered tube rows

This paper presents a numerical calculation and comparison of thermal performance and pressure drop for heat-pipe heat exchangers with aligned/staggered tube rows. In this study, the variations of the number of rows and columns from 1 to 6 for a total 36 arrangements are presented and discussed. From the present results, an optimum arrangement of heat-pipe heat exchangers could be obtained.     

不可逆半导体固态热离子制冷器性能分析和优化

建立了考虑外部有限速率传热过程和热源间热漏的不可逆半导体固态热离子制冷器模型,基于非平衡热力学和有限时间热力学理论导出了热离子制冷器的制冷率和制冷系数的表达式;对比分析了不可逆热离子制冷器与可逆热离子制冷器的发射电流密度特性、电极温度特性以及制冷系数特性;研究了不可逆系统的制冷率与制冷系数最优性能,得到了制冷率和制冷系数的最优运行区间;通过数值计算,详细讨论了外部传热以及内部导热、热源间热漏损失、热源温度、外加电压、半导体材料势垒等设计参数对热离子装置性能的影响。在总传热面积一定的条件下,进一步优化了高、低温侧换热器的面积分配以获得最佳的制冷率和制冷系数特性。结果表明,由于存在内部和外部的不可逆性,热离子装置的发射电流密度及制冷系数都会明显降低;不可逆半导体固态热离子制冷器的制冷率与制冷系数特性呈扭叶型;合理地选外加电压、势垒等参数,可以使制冷器设计于最大制冷率或最大制冷系数的状态。     

Design and optimization of a heat driven thermoacoustic refrigerator

The present paper deals with the design and optimization of a heat driven thermoacoustic refrigerator. A simplified model is developed which enables to pinpoint and examine the most important physical characteristics of a compact traveling wave thermoacoustic refrigerator driven by a traveling wave thermoacoustic engine. The model can explain the so-called traveling standing wave effect in thermoacoustics very well. The position, length and hydraulic radius of the refrigerator are optimized for the maximum total COP. The prime mover efficiency, refrigerator COP and dimensionless dissipation and their impacts on total COP are investigated and discussed. The results indicate that a COP of 28.7% at T_RF,cold = 273 K is achievable.     

联箱式分离型热管实验研究

联箱式分离型热管的多支管并联可能导致流量分配不均,造成部分管道干涸,降低换热效果。搭建了7根管道并联的U型联箱式分离型热管实验平台,以R134a为工质,在800～2 200 W加热功率下,分析热管高效工作的充液率上下限、最佳充液率、热管系统换热特性及管道流量分配。结果表明:热管在充液率为31%～46%时可正常工作,最佳充液率约为42%;确认了各换热支管出现的流量分配不均匀特征,最靠近入口的分支管换热性能最佳,第4～6根换热管流量分配最少、性能最差。     

Maximum exergy input rate from a hot stream in solar‐driven refrigerators

The authors believe that reducing the size of solar‐driven refrigerators and air conditioning systems will make them more attractive to potential users. This paper presents a contribution to understanding the behaviour of such systems with a view to determining the manner in which refrigeration rate, mass flows and heat transfer areas are related. The intention is to make possible the identification of preliminary design rules. The basic thermodynamic problem of how to obtain maximum exergy input rate in a solar‐driven refrigerator is considered. The existence of an optimal refrigerant flow rate for maximum refrigeration is investigated. The analysis proceeds by relating the entropy generation rate, the physical and operating parameters, and the constraints of the system, through well‐established heat transfer relationships. Finally, a thermodynamic analysis determines the optimal characteristics that lead to minimum entropy generation. The second law efficiency is identified as the appropriate figure of merit for the thermodynamic optimum. Copyright © 2001 John Wiley & Sons, Ltd.