利用工业余热的单级氨水吸收式制冷机在制冰生产中的应用

本文介绍了以工业余热为热源的单级氨水吸收式制冷机在工业制冰(蓄冰)与冰藏申的应用。通过生产性实验,初步得出了该机在生产中的性能变化规律及效率。并将该机与压缩式制冷机进行了技术经济比较,阐明了其在工业余热升级利用及节能增效中所起的作用。     

纯低温余热发电系统中余热锅炉的热力学分析

以能量平衡模型和能量平衡方程为依据,对某水泥厂纯低温余热发电系统中的余热锅炉进行了热力学分析,同时分析了各种参数变化对余热锅炉(火用)效率的影响.结果表明:余热锅炉的主要外部损失为排烟(火用)损失,占锅炉总(火用)损失的45.72%;主要内部损失为传热(火用)损失,占锅炉总(火用)损失的11.28%.确定了余热锅炉耗能的薄弱环节,并提出了降低余热锅炉(火用)损和提高余热锅炉(火用)效率的途径和改进措施,为水泥厂进一步展开节能工作提供科学依据.     

带吸收式制冷的汽轮机热电联产

<正> 许多工业部门或其他部门既需要一定电力,也需要一部分热能。有些单位设置了背压式汽轮机进行热电联产以满足热和电这两方面的需求。为了提高热电联产的效率,足够的热负荷是很重要的。通常热负荷是用于干燥、蒸煮以及冬季供暖等等。在某种条件下,热电联产的热负荷往往不足。近年来,利用低品位蒸汽作为热源的吸收式制冷机在国外已得到普及,在我国的应用也越来越多。今后不但工业部门或者其他部门(如大型宾馆等)有条件的均可采用带吸收式制冷的热电联产,冷天可利用余热进行供暖,热天则由吸收式制冷机利用余热供空调,以及日常过程冷却和冷藏等用。这样就可以大大节省电力,使背压式汽轮机进     

纯低温余热发电系统的(火用)分析及其主蒸汽参数优化问题

采用.用分析的方法,分析计算了纯低温余热发电系统入口余热的粗(火用)流分布,指出减少出口余热(火用)损和内部换热损是提高余热锅炉(火用)回收的关键,并在此基础上分析了主蒸汽压力参数与余热锅炉最大回收炯及发电系统最大做功的关系,分析论证其进行优化的原因和必要性,为进一步研究提高纯低温余热发电系统的炯回收率提供了参考.     

低品位余热资源利用方式的探讨

<正>近年来,我国工业领域内的余热资源,特别是高温和中温余热资源利用取得显著效果。但是,与发达国家相比,工业领域内的低温余热资源(低品味余热资源)利用还有一定的差距,且行业内不同企业之间也很不均衡。随着节能工作的不断深入,低温余热资源的利用日益成为节能工作的一个热点和难点,本文分析了低品味余热资源的特点,总结了目前的利用方式和技术进展。1余热资源等级划分工业余热主要指工业企业热能转换设     

低品位热能汽轮机在工业余热利用中的地位

本文介绍了低品位工业余热利用的重要性和低品位热能汽轮机在工业余热利用中的使用方式,所具有的特点以及低品位工业余热利用的发展前景。     

利用低位余热的喷射式制冷机性能研究

研究了使用氟利昂作为工质的喷射式制冷机的性能,编制了计算机仿真程序,分析了状态参数对制冷循环性能的影响。计算结果表明这一装置可以用低位余热驱动,适合于空调系统。     

低品位热能汽轮机在工业余热利用中的地位

本文介绍了低品位工业余热利用的重要性和低品位热能汽轮机在工业余热利用中的使用方式,所具有的特点以及低品位工业余热利用的发展前景.     

基于余热回收的热管换热器应用研究

介绍了热管换热器的工作原理和设计优点,并阐述了热管对其工作介质的要求以及工业余热回收中热管换热器的应用问题。结合某钢厂高温冲刷水余热回收的实例,对热管换热器进行了详细的设计与计算,并把余热回收的热量加以利用,即作为冬季供暖的热源,使得该项目获得了较好的经济效益。分析了热管换热器在余热回收中的技术、经济、环境的可行性,为热管换热器在余热回收的应用提供了借鉴。     

石油化工企业装置余热的综合开发利用

结合利用溴化锂吸收式制冷机回收利用石化企业装置余热的具体实施方案,提出在考虑装置余热的利用方案时,不仅要注重装置余热的充分回收利用,而且要注意考虑水资源的回收利用。     

Probabilistic aspects in the technical and economic analysis of the industrial waste heat recovery system generating useful heat and refrigeration

The technical and economic analysis of the industrial waste heat recovery system, considering probabilistic distribution of the input data is presented. A prospect and rationality of the application of the waste heat boiler and absorption refrigerator has been examined as an example, in view of covering integrated heat and refrigeration demands. The influence of changing ambient conditions as well as the exhaust gas temperature and its flow rate on the overall system performance has been simulated and assessed. Copyright © 2005 John Wiley & Sons, Ltd.     

Optimal waste heat recovery and reuse in industrial zones

Significant energy efficiency gains in zones with concentrated activity from energy intensive industries can often be achieved by recovering and reusing waste heat between processing plants. We present a systematic approach to target waste heat recovery potentials and design optimal reuse options across plants in industrial zones. The approach first establishes available waste heat qualities and reuse feasibilities considering distances between individual plants. A targeting optimization problem is solved to establish the maximum possible waste heat recovery for the industrial zone. Then, a design optimization problem is solved to identify concrete waste heat recovery options considering economic objectives. The paper describes the approach and illustrates its application with a case study.     

径向热管换热器在天然气工业炉低温烟气中的应用

当前我国的能源形势紧张,能源利用状况令人担忧.在一些高耗能的企业,工业生产中排放的中低温烟气余热由于回收难度高、回收成本大等问题,一直得不到合理的利用,如何合理回收成为亟待解决的难题之一.简要介绍了一种新型余热利用换热设备——径向热管换热器,提出了计算热管换热器经济性评价指标的方法,并以某工厂低温烟气余热回收工程为实例,对烟气余热的回收利用进行了技术和经济效益分析.实践应用证明,径向热管换热器在工业低温烟气余热回收中有很好的实用性和可行性.     

Performance analysis of a waste‐heat‐powered thermodynamic cycle for multieffect refrigeration

A multieffect refrigeration system that is based on a waste‐heat‐driven organic Rankine cycle that could produce refrigeration output of different magnitudes at different levels of temperature is presented. The proposed system is integration of combined ejector–absorption refrigeration cycle and ejector expansion Joule–Thomson (EJT) cooling cycle that can meet the requirements of air‐conditioning, refrigeration, and cryogenic cooling simultaneously at the expense of industrial waste heat. The variation of the parameters that affect the system performance such as industrial waste heat temperature, refrigerant turbine inlet pressure, and the evaporator temperature of ejector refrigeration cycle (ERC) and EJT cycles was examined, respectively. It was found that refrigeration output and thermal efficiency of the multieffect cycle decrease considerably with the increase in industrial waste heat temperature, while its exergy efficiency varies marginally. A thermal efficiency value of 22.5% and exergy efficiency value of 8.6% were obtained at an industrial waste heat temperature of 210°C, a turbine inlet pressure of 1.3 MPa, and ejector evaporator temperature of 268 K. Both refrigeration output and thermal efficiency increase with the increase in turbine inlet pressure and ERC evaporator temperature. Change in EJT cycle evaporator temperature shows a little impact on both thermal and exergy efficiency values of the multieffect cycle. Analysis of the results clearly shows that the proposed cycle has an effective potential for cooling production through exploitation of lost energy from the industry. Copyright © 2014 John Wiley & Sons, Ltd.     

Determining the best type of heat exchangers for heat recovery

It is a common problem to choose the most appropriate heat exchanger configuration for heat recovery. In this study, a new model has been developed for determining the area and type of the most appropriate waste heat recovery heat exchanger for maximum net gain. A non-dimensional E number has been defined based on known technical and economic parameters such as the life-time, unit area cost of the heat exchanger, lower heating value of the fuel, overall heat transfer coefficient of heat exchanger, boiler efficiency, operation time per year, heat exchanger effectiveness, ratio of heat capacities, annual variation of the temperature of fluids supplied to the heat exchanger and present worth factor. The non-dimensional E numbers has been demonstrated in graphical forms as a function of NTU and ratio of heat capacities and corresponding heat exchanger area giving maximum net gain can easily be obtained from these graphs. The best heat exchanger type and its area can be determined comparing net gains or effectiveness of heat exchangers at NTU_max. Application of the new method has been given with a case study as a sample calculation.     

A review of thermodynamics and heat transfer in solar refrigeration system

Solar energy is one of the most efficient, clean and affordable energy alternatives available today. With the current concerns about global warming and ever increasing energy rates, countries are seriously looking for domestic and industrial usage of solar energy. In the present study, a detail review of the application of solar energy for refrigeration systems has been carried out. The utilization of solar energy for refrigeration systems would help in improvement of energy economics, energy consumption and energy efficiency. The review focuses especially on solar panel, desiccant fluid for icemaker and its components. The study also includes thermodynamic equation and material for making component of refrigeration to improve the coefficient of performance. Study around the economic evaluation and solar performance coefficient in the type of refrigerator, modeling and simulation, mathematical equation of heat transfer and type of absorption used are other topics that could be considered.     

Evaluation of refrigerating and air-conditioning technologies in heat cascading systems under the carbon dioxide emissions constraint: the proposal of the energy cascade balance table

The aim of this study was to evaluate the refrigerating and air-conditioning technologies in cases of introducing both heat cascading systems and thermal recycling systems in industries located around urban areas. It is necessary to introduce heat cascading systems in the industrial sector in Japan to reduce carbon dioxide emissions. The concept of heat cascading is the multi-stage use of thermal energy by temperature level. This paper introduces three energy policies for introducing the heat cascading systems. The author develops an energy cascade model based on linear programming so as to minimize the total system costs with carbon taxes. Five cases are investigated. Carbon dioxide emission constraints result in the enhancement of heat cascading, where high temperature heat is supplied for process heating while low temperature heat is shifted to refrigeration. It was found that increasing the amount of garbage combustion waste heat could reduce electric power for the turbo compression refrigerator by promoting waste heat driven ammonia absorption refrigerator. In addition, this study proposes an energy cascade balance table with respect to the temperature level.     

以SOFC为发电设备的热泵型BCCHP系统

针对目前建筑冷热电联供系统发电设备效率低和余热利用方式不当造成能耗偏高的现状,提出了一种以固体氧化物燃料电池为发电设备的热泵型BCCHP系统,介绍了该系统的运行原理及结构配置特点,通过对系统组件的建模、模拟与集成,以一个80kW电力需求的用户为例进行实例研究,实例表明:在设计工况下,热泵型SOFC-BCCHP系统冬季的发电效率、供热效率分别为46.3%、51.9%,夏季系统的发电效率、供冷效率分别为46.3%、32.5%,系统的综合效率均较传统系统有明显提高,是高效的能源转换方式与高效的能源利用方式的综合,具有一定的推广价值.     

Performance of a combined organic Rankine cycle and vapor compression cycle for heat activated cooling

Heat activated cooling has the potential of utilizing thermal sources that currently go unused such as engine exhaust heat or industrial waste heat. Using these heat sources can provide enhanced energy utilization and reduced fuel usage in applications where cooling is needed. The concept developed here uses waste heat from stationary and mobile engine cycles to generate cooling for structures and vehicles. It combines an organic Rankine cycle (ORC) with a conventional vapor compression cycle. A nominal 5 kW cooling capacity prototype system was developed based on this concept and tested under laboratory conditions. In order to maintain high system performance while reducing size and weight for portable applications, microchannel based heat transfer components and scroll based expansion and compression were used. Although the system was tested off of its design point, it performed well achieving 4.4 kW of cooling at a measured heat activated COP of 0.48. Both the conversion and 2nd law efficiencies were close to the model results, proving it to be an attractive technology. The measured isentropic efficiency of the scroll expander reached 84%, when the pressure ratio was close to the scroll intrinsic expansion ratio. The reduced cooling capacity was attributed to off design operation.     

工业余热跨季节储热系统优化及经济性分析

以工业余热跨季节储热用于区域供热系统为研究对象,在一个已有的1 MW工业余热系统的基础上,搭建工业余热跨季节储热系统设计方案,通过系统模拟对系统储热、取热过程进行分析。分析结果表明:工业余热跨季节储热适合长周期、大规模蓄热;储热体体积和循环流量应根据系统热源和取热装置特性进行合理匹配,在合理匹配范围内可参考系统经济性确定系统最优配置。最后,通过费用年值法分析优化后的系统经济性,分析表明工业余热跨季节储热用于区域供热成本仅略高于燃煤供热,相比燃气供热具有非常可观的经济性。