空调制冷及热电冷联产系统的能耗分析

针对溴化锂制冷尤其是在热电冷三联产时是否比压缩式制冷节能的争论，提出了以煤为对象的等效燃料利用系数ＫＳ的概念和计算公式，用以地比分析了三者的ＫＳ值，得出在目前发电效率水平下热电冷三联产在采用高压机组时一般才是节能的，在其他情况下是否节能是有条件的。     

三效压缩吸收式制冷循环的仿真分挝

针对高温发生器发生温度过高而引起的腐蚀影响三效溴化锂吸收式制冷系统推广应用的难题,提出了在基本逆串联三效溴化锂制冷系统中附加一个压缩机的系统方案,并经分析认为在蒸发器和吸收器之间布置压缩机最佳。这种增压吸收式循环,补偿相当于制冷量2％～10％的电能即可使驱动热源温度降低约5～40℃,达到与传统循环相当的制冷系数。     

电压缩式制冷循环与吸收式制冷循环的热力学比较分析

采用效率与损失分析方法,计算比较了电压缩式制冷循环与单效吸收式制冷循环的效率及两种制冷循环在典型工况下各环节的损失。结果表明,当采用合适的发生器温度和热源温度时,两种制冷循环的效率基本相同;电压缩式制冷循环的主要损失发生在压缩机环节,吸收式制冷循环的主要损失发生在吸收器和发生器。讨论了两种制冷循环的改进途径。     

空气源燃气机热泵运行过程的(火用)分析

对空气源燃气机热泵的制冷过程、制热过程进行了火用分析,得出了各设备的火用效率、火用损及系统总热效率,建立了火用流图。采用燃气机热泵,在制冷、制热工况下系统总热效率分别为169.72%、168.17%。为提高燃气机热泵的火用效率,应选用效率高的燃气发动机。燃气发动机余热回收对系统总热效率的提高影响很大。     

Thermodynamic investigation of an integrated DI diesel engine with waste heat operated rankine cycle

ABSTRACT

A DI Diesel Engine has been integrated with a Rankine Cycle for making a proposed ‘integrated power generation cycle’. The heat of engine’s exhaust gases and jacket’s water is as a single heat source to produce additional output power through the Rankine Cycle. In exergy analysis, destruction of input exergy is nearly 64.13% due to irreversibilities. The useful exergy output is about 30.3%. The exhaust exergy lost to atmosphere is 5.39%, which is smaller than 20.83% of exhaust energy loss of its input, whereas the useful energy output is almost 38.02%. Moreover, there is the reduction in the BSFC due to the recovery of the exergy from the waste heat. The average reduction in the BSFC is about 18.42%. The results of this proposed cycle also show that the integration of the Diesel Engine with the Rankine Cycle has drastic effect on the efficiencies based on exergy and energy.     

蒸汽溴化锂机组用于热电厂的效益分析

为便于比较电动压缩式制冷机与蒸汽溴化锂吸收式制冷机的性能,在对现有制冷机性能评价指标分析基础上,提出了修正后的电动压缩式制冷机的性能系数———等效性能系数。结合某热电厂制冷空调系统改造工程实例进行了效益计算,结果表明利用热电厂抽汽驱动蒸汽溴化锂吸收式制冷机制冷具有节电效益。     

热泵回热型热电厂设计模式的比较分析

介绍了热泵回热型热电厂的概念、类型及设计模式。对凝汽式热泵回热型热电厂在2种设计模式下的节能性进行了比较分析,在相同的电厂规模下,第2种设计模式可承担更大的供热负荷,但热泵机组及外部余热回收装置的设备造价也相应提高。     

燃气-蒸汽联合循环与吸收式热泵的综合应用研究

与普通蒸汽轮机相比,燃气轮机在节能环保方面更具优势。尤其是燃气-蒸汽联合循环越来越受到重视。分析了热泵系统和联合循环系统,对热电联供系统进行了能量分析,最后通过案例分析得出结论:以天然气为燃料的热电联供系统能够减少环境污染,提高能量利用率,对我国节能低碳事业有重要意义。     

热电冷联产与热电联产加电制冷能耗比较分析

将热电冷联产与热电联产加电制冷能耗比较分解成供热、供电、供冷三种煤耗差进行分析,建立了以热电联产加电制冷为基准的三种煤耗差数学模型,探讨了煤耗差随冷热负荷的变化情况,给出了目前一般情况下热电冷联产的节能条件、判据及措施。     

Exergetic performance optimization of an endoreversible intercooled regenerated Brayton cogeneration plant. Part 2: Exergy output rate and exergy efficiency optimization

The exergy output rate and exergy efficiency performances of an endoreversible intercooled regenerative Brayton cogeneration plant are optimized based on the model which is established using finite time thermodynamic in Part 1 of this paper. It is found that the optimal heat conductance allocation of the regenerator is almost zero. When the total pressure ratio and the heat conductance allocation of the regenerator are fixed, it is shown that there exist two optimal intercooling pressure ratios, and two optimal groups of the heat conductance allocations among the hot-, cold- and consumer-side heat exchangers and the intercooler, which correspond to a maximum dimensionless exergy output rate and a maximum exergy efficiency. When the total pressure ratio is variable, there exist two optimal total pressure ratios which correspond to a double-maximum dimensionless exergy output rate and a double-maximum exergy efficiency, also the corresponding exergy efficiency and exergy output rate are obtained. The effects of the total heat exchanger conductance and the consumer-side temperature on the double-maximum dimensionless exergy output rate and the double-maximum exergy efficiency are discussed. It is found that there exists an optimal consumer-side temperature which correspond to a thrice- maximum dimensionless exergy output rate, and the intercooling process is not necessary by taking exergy efficiency as the objective when the consumer-side temperature is high.     

热泵循环的(火用)分析与研究

指出了<热泵定义的拓展及其(火用)效率表达式的改进>一文中存在的问题,引证文献证明了热力学与工程领域对热泵的定义是一致的.通过(火用)分析导出热泵(火用)效率的表达式,从而证明原文作者得出ηex＞1的结论的理论缺陷.     

天然气动力能量系统的分析与评价

对以天然气为能源的发动机驱动的热电冷三联供系统进行了技术经济分析，并与电动空气源热泵机组作了比较，工程实例计算结果表明该系统不仅具有较高的一次能源能量利用率和环保效果，而且在技术经济上是合理的。     

海水源热泵系统的经济分析

利用经济分析方法建立了海水源热泵系统的经济分析模型,并对海水源热泵系统流程的成本进行计算,结果表明热泵机房的流成本最高,因此可以通过提高热泵效率等途径来减小流成本。建议以流成本最小作为约束函数,并将经济分析法用于海水源热泵系统的优化设计中。     

燃气锅炉烟气余热回收热泵系统应用与分析

对某烟气余热回收热泵系统进行了实测,结果表明,热泵综合能效比达到4.0以上。针对热泵系统应用过程中遇到的问题提出了改进措施,并从节能、经济和环境效益多角度对热泵系统进行了分析。     

天然气热泵在华南地区的应用前景

天然气热泵在华南地区用于制冷对电网和燃气管网可起到削峰填谷作用。介绍了天然气热泵的工作原理和节能、环保等特点及国内外天然气热泵的应用情况,分析了华南地区推广应用天然气热泵的前景。指出天然气热泵是天然气和空调产业的重要发展方向之一,在华南地区推广应用可以产生显著的经济、社会效益。     

供热方式的技术与经济性分析

对采用热电联产、区域供热锅炉房、燃气热水器、直接用电、电蓄热锅炉、燃气机热泵、电动空气源热泵、电动水源热泵等供热方式的技术及经济性进行了探讨。     

热泵定义的拓展及其(火用)效率表达式的改进

认为热力学理论中定义的热泵与工程领域定义的热泵有所不同 ,按热力学理论中的定义 ,存在热泵效率大于 1的错误。提出了符合分析基本理论原则的效率表达式 ,并将修正的效率及供系数、损系数、损率同时纳入热泵分析过程     

天然气锅炉烟气余热利用节能改造工程实测分析

针对天然气锅炉等热能动力设备排烟温度高,造成能源浪费和环境污染的现状,应用自主研发的高效紧凑防腐型烟气冷凝热能回收利用装置,对一既有锅炉房进行了烟气余热回收利用节能改造和跟踪实测。分析了锅炉耗气量、排烟温度及热效率的变化,结果表明,排烟温度由150～200℃降到50℃以下,仅烟气余热回收装置就使锅炉热效率提高10%以上,且由于该装置提高了锅炉进水温度,从而提高了锅炉本体燃烧效率,使锅炉低热值总效率超过100%,锅炉高热值效率超过95%,锅炉房总节能率达25.6%。     

Study of performance parameter optimisation of resorption cogeneration utilising heat and mass recovery

In the present scenario, one of the global issues is energy crisis, and it is found that effective utilisation of low-grade waste heat energy as potential solution to this crisis, which could be easily used with the cogeneration plant. In this work, an attempt is made to implement a mass and heat recovery system with a basic resorption cogeneration unit. Low-grade solar energy is utilised by the expansion machine and ammonia resorption unit, and the plant produces a dual output of cooling effect and electricity. The problem of variation reaction rate is sorted out by introducing a buffer prior to the expansion machine; similarly, the deficiency of chemisorption is overcome by a pair of resorption cycles. Under various operating conditions, six resorption pairs were analysed and it was found that the SrCl₂–MnCl₂ pair to be the best pair. Exergy analyses were made using the equation solver.     

同时供冷供热双级压缩制冷热泵循环系统分析

同时供冷供热双级压缩制冷热泵循环是1种新型热力循环,它能够同时对制冷、制热量进行调节,以满足用户的冷热量需求。本文建立了该循环系统的分析模型,并对其进行了研究,结果表明:在给定的传热温差下,影响该系统效率的主要因素是室外空气温度、制冷剂流量比;在低制冷剂流量比下,该系统产生损失的主要部位依次为热源侧换热器、热水加热器、第一节流阀、高压压缩机;在高制冷剂流量比下,该系统产生损失的主要部位依次为第二节流阀、热水加热器、高压压缩机、低压压缩机。通过在系统中增加1个经济器对该系统进行了优化,并对比分析了系统优化前后的效率和损失,结果表明:经济器能提高系统的效率,大幅度降低发生在第一节流阀和第二节流阀的损失,但对其他部件损失的影响很小。