结合燃气-蒸汽联合循环的液化天然气冷能发电利用

提出了结合燃气-蒸汽联合循环的利用液化天然气（liquefied natural gas,LNG）冷能的朗肯循环发电系统,实现LNG冷能梯级利用。朗肯循环蒸发器和燃气-蒸汽联合循环凝汽器换热量匹配一致,循环水系统实现闭式且不受环境温度影响。对系统进行模拟并分析了影响系统的主要参数,结果显示：随着朗肯循环冷凝温度的降低,朗肯循环净输出功率和净效率均有提升;随着循环水温度的提高,朗肯循环的净输出功率和净效率都将提高,而蒸汽轮机输出功率减少,但二者总的输出功率降低幅度不大。     

液氮汽车的可行性分析

基于朗肯循环过程，对液氮驱动汽车的可行性进行了理论研究，研究了不同的初始膨胀压力的温度下，分别进行等温膨胀和绝热膨胀时，低温发动机所能获得的单位制冷可用能和相应的Yong效率，并对采用甲烷-液氮两级联合的朗肯循环进行了理论分析，提出了进一步提高其性能的途径。从经济性的角度，认为液氮汽车相对于其它零排放汽车有优势。     

液氮发动机换热器的结霜研究

液氮汽车换热器的性能决定着液氮发动机的工作效率.分析了结霜对换热器性能的影响,阐述了换热器结霜的数学过程,并对如何避免换热器的结霜进行研究.提出了两种新型的避免结霜方法:采用预混和式换热器和改变翅片间距.通过试验发现这两种方法可以有效的防止换热器的结霜,提高换热器的汽化效率.     

利用气体动力循环的LNG双动力汽车

分析了三种清洁排放汽车--压缩空气汽车、液氮汽车和LNG汽车的特点.提出一种利用气体动力循环的LNG双动力汽车系统,将开式朗肯循环与内燃机循环结合,优势互补.结果表明,LNG双动力汽车系统中的天然气开式朗肯循环输出功远高于液氮汽车.LNG双动力气车系统可用能较普通LNG汽车增加9.82%,且对环境没有污染,节能环保效果明显.     

变温热源不可逆布雷顿制冷循环制冷率和制冷系数优化

用有限时间热力学方法分析变温热源不可逆简单布雷顿制冷循环的特性,分别以制冷率和制冷系数为优化目标,优化了循环中换热器的热导分配以及工质和热源间的热容率匹配,并采用数值计算分析了压比、换热器总热导、压缩机和膨胀机效率、工质热容率等参数对最优制冷率和制冷系数的影响特点.所得结果对工程制冷系统设计有一定的指导意义.     

中国先进研究堆(CARR)冷中子源装置设计

对中国在建的核功率为60 MW的中国先进研究堆中冷中子源系统的设计作了总体描述.该冷中子源采用液氢作为慢化剂,主要由两个分系统氢循环系统和氦制冷系统构成.氢循环系统中的冷包设计为带氦助冷通道的液氢层为月牙形的冷包.氢在连接冷包与氢氦换热器的单管内进行两相热虹吸循环.冷包材料和慢化剂氢的核发热通过氦制冷系统产生的冷氦带走,氦制冷系统采用带液氮预冷的逆布雷顿制冷循环.     

回热式布雷顿制冷循环的性能优化

基于回热式不可逆布雷顿制冷循环模型,导出循环的制冷率、性能系数和输入功率等一些重要性能参数的一般表达式及制冷率和性能系数之间优化关系所满足的方程,研究回热和各种不可逆性对其优化性能的影响,讨论了循环的优化运行区间及其性能界限,确定了最佳传热面积。通过数值计算分析了设计参数对循环的制冷率、性能系数和输入功率的影响。     

内可逆闭式中冷回热布雷顿循环功率效率特性

应用有限时间热力学的方法分析了恒温热源条件下内可逆闭式中冷回热布雷顿循环的无因次功率和效率特性．导出了无因次功率及效率的解析式．通过数值计算，得到了分别对应于循环功率和效率的最佳中间压比分配，并研究了中冷度、回热度以及高低温侧换热器有效度对循环性能的影响．     

有机朗肯循环发电系统中换热过程模拟与系统经济性分析

有机朗肯循环发电系统中的能量主要损失在换热设备中。换热设备性能对其发电效率有着直接的影响。为提高有机朗肯循环发电系统的经济性,以最小电力生产成本为目标函数,建立经济性模型,并以实际搭建的有机朗肯循环发电系统对模型进行优化,对安装预热器和过热器的经济性进行分析。研究结果表明:电力生产成本主要受热源介质流量、冷却水流量、系统发电功率、蒸发器节点温差及蒸发温度的影响;在有机朗肯循环发电系统中,尤其是在中大型发电系统中,预热器的安装是经济可靠的;过热器的安装对电力生产成本的增加值较小,而其可提高系统的稳定性、延长系统的使用寿命。     

传热不可逆回热式布雷顿制冷机分析

用有限时间热力学方法分析实际隐态制冷装置性能，导出了恒温和变温热源条件下实际闭式回热式布雷顿制冷循环制冷率与压力比和制冷系数与压力比之间的解析关系。考虑了不可逆性包括高，低温侧换热器和回热器的不可逆传热损失，压缩机和膨胀机中的非等熵压缩和膨胀损失，以及管路系统中的压力损失，通过优化两个换热器和回热器之间的热导率分配或传热面积分配可得循环最优性能，由数值算例给出了各项损失对循环制冷率和制冷系数的影响。     

A theoretical study on a novel combined power and ejector refrigeration cycle

A new combined power and refrigeration cycle is proposed for the cogeneration, which combines the Rankine cycle and the ejector refrigeration cycle by adding an extraction turbine between heat recovery vapor generator (HRVG) and ejector. This combined cycle could produce both power output and refrigeration output simultaneously, and could be driven by the flue gas from gas turbine or engine, solar energy, geothermal energy and industrial waste heats. Parametric analysis and exergy analysis are conducted to examine the effects of thermodynamic parameters on the performance and exergy destruction in each component for the combined cycle. The results show that the condenser temperature, the evaporator temperature, the turbine inlet pressure, the turbine extraction pressure and extraction ratio have significant effects on the turbine power output, refrigeration output, exergy efficiency and exergy destruction in each component in the combined cycle. It is also shown that the biggest exergy destruction occurs in the heat recovery vapor generator, followed by the ejector and turbine.     

The CNPM thermal heat pump. Part 1 — general description and thermodynamic analysis

A research programme, funded by CNR (National Research Council), has been undertaken by CNPM since 1973. The aim of the programme is the construction and testing of a prototype thermal heat pump. The most significant component is an organic Rankine cycle engine, driving the compressor of a heat pump. Since the heat rejected by the engine is supplied to the user — water for domestic heating — the whole system performs as a ‘heat multiplier’, converting the high temperature heat given to the engine into a larger amount of low temperature heat, to be used for domestic heating.In this paper, the selection criteria for the working fluid — a completely fluoro-substituted hydrocarbon — and the main thermodynamic data of both power and heat pump cycles, are discussed; the finally adopted plant configuration is described, with particular emphasis on the influence exterted by the working fluid nature on the heat exchangers and turbo-machinery dimensions and performance. A discussion on the merits of the single fluid solution (ie the same working fluid in the power and the heat pump cycle) and dual fluid solution is also carried out. The feasibility of a low-temperature heat distribution, based on compact-surface, natural-draft convectors, with the relevant advantages on the Rankine and heat-pump cycles, is also investigated.Finally, the expected overal; system performance is given, both at design and part-load conditions. As a premium for the rather complex but efficient thermodynamicscv of the system, significant energy savings are obtained in all situations.     

全封闭式涡旋膨胀机在车用有机朗肯循环中的特性研究

本文针对中低温余热特性搭建了2kW目标发电量的小型有机朗肯循环发电系统。实验研究了全封闭式涡旋膨胀机在有机朗肯循环系统中的参数特性。通过改变膨胀机进出口的状态,研究了运行压比和转速对于膨胀机单体及系统性能的影响。性能参数主要包括等熵效率、容积系数、循环热效率及循环净功。结果表明:膨胀机运行压比是影响系统性能的重要参数,循环净功随压比的增大而增加,循环热效率及膨胀机的等熵效率随压比变化均存在最优值;考虑内泄漏及摩擦损失等影响,最优运行压比一般应略大于膨胀机设计比;提高膨胀机转速能有效减少内泄漏损失。     

低温余热发电技术在煤化工项目上的应用

研究了采用有机朗肯循环(ORC)的低温余热发电技术。为了有效利用煤化工项目的低温凝液余热资源,在计算工艺凝液余热容量的基础上确定了合理的ORC余热利用方案,利用ORC余热发电机组代替原有的循环水冷却器,以便在完成对工艺凝液冷却的同时实现余热资源发电收益。分析结果表明:该余热发电项目的净发电功率为516k W,节约原有冷却塔循环水泵消耗的功率为110k W,年收益电量达500.8万度,年节约标准煤1812.4吨。     

Stirling engine heat pumps

A Stirling engine is a thermal system that may be used to produce power from a high temperature heat source or as a refrigerator and heat pump to deliver energy at a higher temperature than abstracted from the source. A Stirling engine may therefore be used as the driver for natural gas heated air conditioning/heat pump Rankine cycle vapour compression systems or itself be used as the refrigerating/heat pump system requiring an input of work. Two Stirling systems, one acting as the driver, the other as the heat pump may be combined into the Stirling-Stirling or duplex Stirling arrangement. This paper touches briefly on a number of topics about fundamental aspects and recent developments in this field.     

基于PSO算法优化的热水分流式双级ORC系统

以有机朗肯循环的结构优化为基础,建立了热水分流式双级有机朗肯循环数值模型,以粒子群算法为计算方法分析系统设计时最大净输出功,通过理论分析得到了影响系统净输出功的独立变量为热水经过高压蒸发器时换热后的温度和热水出口温度.结果 表明热水分流式双级有机朗肯循环可以对热水进行更好的利用,高压循环蒸发温度随着热水入口温度升高更快...     

过冷度对地热发电非共沸工质有机朗肯循环热力性能的影响

有机朗肯循环（organic Rankine cycle,ORC）是利用中低温地热能（< 150℃）发电的主要途径,在实际运行中,非共沸工质往往会冷凝至过冷状态。分析了冷凝过冷度对非共沸工质ORC热力性能的影响,建立了ORC、内回热（internal heat exchanger,IHE）ORC的热力学模型,以净输出功最大为目标函数优化了工质的蒸发压力,并开展了系统的㶲分析。结果表明：过冷度影响了工质与冷源换热流体间的温度匹配特性,受夹点温差的限制,随着过冷度的增加,工质的冷凝压力上升;过冷度亦改变了预热器和蒸发器的热量分摊,随着过冷度的增加,最佳蒸发压力亦上升。混合工质异丁烷/异戊烷的质量配比为0.4：0.6时,净输出功受过冷度的影响最大,当过冷度为2℃时,净输出功下降了4.36%。IHE回收膨胀机排汽的余热,提高了预热器入口温度,可提高过冷ORC系统净输出功0.55%。过冷度增大了冷凝器的㶲损失;采用内回热冷凝器的㶲损失降低了24.7%。     

Exhaust gas energy recovery system of pneumatic driving automotive engine

Almost the same quantity to net output work of energy has been carried out and wasted by exhaust gas in typical automotive engine. Recovering the energy from exhaust gas and converting to mechanical energy will dramatically increase the heat efficiency and decrease the fuel consumption. With the increasing demand of fuel conservation, exhaust gas energy recovery technologies have been a hot topic. At present, many researches have been focused on heating or cooling the cab, mechanical energy using, and thermo-electronic converting. Unfortunately, the complicated transmission of mechanical energy using and the depressed efficiency of thermo-electronic converting restrict their widely applying. In this paper, a kind of pneumatic driving automotive engine exhaust gas energy recovery system, in which highly compressed air acts as energy storing and converting carrier, has been established. Pneumatic driving motor can produce moderate speed and high torque output, which is compatible for engine using. The feasibility has been certificated by GT-Power simulation and laboratory testes. The technologies about increasing recovery efficiency have been discussed in detail. The results demonstrated that the in parallel exhaust gas energy recovery system, which is similar to the compound turbo-charger structure can recovery 8 to 10 percent of rated power output. At last, a comprehensive system, which includes Rankine cycle based power wheel cycle unit etc, has been introduced.     

Thermal and exergoeconomic analysis of a novel solar driven combined power and ejector refrigeration (CPER) system

In the present study, a novel solar driven combined power and ejector refrigeration system (CPER) of 50 kW power capacity composed of an ORC (organic Rankine cycle) and an ejector refrigeration system is investigated. Solar driven CPER system is composed of two main cycles: collector cycle and refrigeration cycle. The collector cycle is made of a U-tube ETC and circulation pump and the ejector refrigeration cycle consists of generator, turbine, ejector, heat exchanger, condenser, evaporator, expansion valve, and pump. Thermodynamic performance of the proposed CPER system is evaluated and a thermo-economic analysis is conducted using the SPECO (specific exergy costing) method. A parametric study showed the effects of condenser temperature, evaporator temperature, generator pressure, turbine back pressure and turbine extraction ratio. The genetic algorithm optimization analysis is conducted which shows 25.5% improvement in thermal energy, 21.27% in exergy efficiency, and 7.76% reduction in the total cost of the CPER system. The results reveal that the performance of the CPER system is considerably improved at higher temperatures of generator and evaporator.