分布式热电联产中热电比的确定

分布式供能是国际上近几年发展起来的一种新的能源供应概念和方式。在分布式热电联产系统中,余热锅炉补燃是调节热电负荷的有效手段,选择合适的补燃率有助于提高余热锅炉和分布式热电联产系统的效率。本文基于上海理工大学分布式热电联产实验台的数据,通过与购买市电＋单独燃油锅炉供热进行比较,给出了一种确定最佳热电比的方法。     

Capstone展出新生活经验列的微型涡轮

正据《Gas Turbine World》2015年11~12月刊报道,美国Capstone涡轮公司已经展出新系列的微型涡轮,目的在于增加它在CHP(热电联产)市场的份额。1 MW额定功率的C1000S微型涡轮结合了许多系统和设计的升级改进,意图是改进整个产品的质量并增加微型涡轮所有者在市场上的应用份额,积累专门针对CHP(热电联产)和CCHP(冷热电联产)应用方面     

热电联产技术与管理

本书全面系统地探讨了热电联产技术的发展和现状,阐述了热电联产的技术特征。全书突破了传统意义上的热电联产概念,不仅介绍了以蒸汽轮机为主的热电联产形式,还介绍了以燃气轮机为主、以往复式内燃机为主、以微型燃气轮机为主、以燃料电池为主的热电联产形式。本书分析了它们的经济性、可靠性、环保性能,分析了选型特征以及运行维护,还从管理的角度介绍了热电联产的节能分析、环保分析、热负荷分析等。     

小型热电联产蒸汽供热系统的能耗分析

目前,有些小型热电联产系统运行不合理、冷源损失大、节能效果不理想.通过对某小型热电联产系统全年运行状况的凋查,计算了热电机组的发电效率、热效率及汽机冷源能量损失,分析了小型热电联产系统能耗大的主要原因,提出了提高热电联产系统能源利用效率、改进热电联产集中供热形式等措施,为热电联产系统改造和扩建工作提供参考.     

小型热电联产系统能耗分析

针对部分地区小型热电联产系统运行不合理、冷源损失大、节能效果不理想的问题,通过对某小型热电联产系统全年运行状况的调查,计算了热电机组的发电效率、热效率及汽机冷源能量损失,分析了小型热电联产系统能耗大的主要原因,提出了提高热电联产系统能源利用效率、改进热电联产集中供热形式的措施,为热电联产系统改造和扩建工作提供参考。     

Bowman公司和Nedalo公司签署供货协定

英国微型燃气轮机发电系统开发商Bowman公司和小型热电联产装置生产商Nedalo公司签署了一份供货协定。协定的第一阶段，Nedalo将在欧洲范围内销售Bowman电力系统，第二阶段在美国。 两家公司还公开了他们的第一张供货单，英国某处的一整套热电联产装置。 Nedalo是重要的热电联产设备供应商之一，在英国有450个用户，全欧洲有2000个用户。 Nedalo的商业负责人，Dudley McDonald解释说：“我们认为燃气轮机联产是小型热电联产的发展方向。我们非常高兴和这项多用途技术的重要开发商进行合作。” Bowman公司和Nedalo公司签署供货协定…     

热电冷联产的节能分析

随着节能的不断深入发展 ,在热电联产的基础上发展了一种新的形式———热电冷联产联供。本文从火用的角度出发 ,比较了热电冷联产和热电联产电动制冷两种方式的能源利用率 ,指出热电冷联产节能的条件。     

分布式能源

所谓“分布式能源”是指分布在用户端的能源综合利用系统。一次能源以气体燃料为主,可再生能源为辅,利用一切可以利用的资源;二次能源以分布在用户端的热电冷（植）联产为主,其他中央能源供应系统为辅,实现以直接满足用户多种需求的能源梯级利用,并通过中央能源供应系统提供支持和补充;在环境保护上,将部分污染分散化、资源化,争取实现适度排放的目标。     

70 kW燃料电池热电联产系统水热管理研究

质子交换膜燃料电池堆的电效率约为50%,电化学反应剩余的能量要以热量的形式散失,造成巨大能量浪费,开发基于燃料电池的热电联产系统可以高效地产生电力和热水,并显著提高系统的能量效率。在MATLAB/Simulink平台上搭建了70 kW级燃料电池热电联产系统,包括燃料电池电模型、热管理模型和热电联产系统综合动态模型,并开发了一种智能控制算法进行水热管理,将电堆运行温度控制在70℃左右,在保证电堆正常运行的前提下,提升热能回收效率并降低系统寄生功率。结果表明该系统可以有效地回收燃料电池反应所产生的废热,在增大外部负载提高电堆电效率的同时,热电联产效率会逐渐增高然后降低,热电联产最高效率可以达到83.5%。     

热电(冷)联产系统的优化性能

依据有限时间热力学原理导出了不可逆热电联产和热电(冷)联产系统在系统最大火用输出时的基本优化关系,确定了热电(冷)联产系统优化参数和优化构形选取范围,得到了供热(制冷)和发电间的匹配优化特性,通过数值算例得出不同参数对系统性能影响的规律。所得结论可为热电(冷)联产系统的优化设计和最佳工况选择等提供理论依据。     

Micro-CHP: U.S. market potential and complex challenges

The widespread deployment of distributed generation (DG) and CHP technologies is seen as a way to improve the efficiency, quality, and reliability of energy delivery in the future. Micro-CHP products are likely to play a role in the utility of the future - but the extent of this role will vary by region. Dr. Samuel Bernstein and Dr. Stu Knoke, Energy International, Inc., USA focus on U.S. market opportunities for micro-CHP, and the complex challenges that must be addressed in order to gain a foothold in the U.S. market.     

Investigation of a 5 kW micro-CHP PEM fuel cell based system integrated with membrane reactor under diverse EU natural gas quality

This work investigates the techno-economic assessment of a 5 kW micro-cogeneration system based on membrane reactor and PEM fuel cell flexible towards different natural gas qualities. The flexibility of the system is evaluated for four typical natural gas compositions from different European countries featuring an average condition and three extreme cases. The optimal system design conditions are determined together with performance variation as function of NG composition and load. The sweep gas and vacuum pump are explored as options to reduce the membrane surface area, outlining the efficiency advantages of the former (41.21% vs. 39.24%). Simulations at partial load show that the electric efficiency increases until 60–70% of the load in both cases, then quickly drops. Micro-CHP performance are used as input to determine the specific system target cost (€/kW) based on a yearly energy and economic analysis. The first reveals that the primary energy savings is always positive outlining the environmental benefit of FERRET system application respect to the reference separated production. The target cost considering its application to two dwellings is around 2000 €/kW.     

Impact of micro-combined heat-and-power systems on energy flows in the UK electricity supply industry

The effects of applying micro-CHP systems to a single dwelling, and to various dwellings within a group, are investigated by using gas and electricity consumption data recorded on a 1-min time base across a full year. Micro-CHP systems based on Stirling engines and fuel cells are predicted to supply 25–46% of the single dwelling's annual electricity demand. For all days of the year, the daily load factor of the resultant load placed on the electricity network is reduced, suggesting that the overall effect of micro-CHP systems will be to provide highly dispersed base-load generation. Consideration of various penetration levels of a 1 kW Stirling engine micro-CHP system of 15% electrical efficiency indicates that the maximum reduction in the aggregate peak load for a single distribution transformer will be about 44% on a winter's day, but only 3% on a summer's day. An alternative implementation of 3 kW fuel cell systems of 50% electrical efficiency would yield significant reductions (both in the peak load and the daily requirement for network electricity) at low penetration levels, with significant reverse flows occurring at the distribution transformer once the penetration level exceeds approximately 15% on a winter's day.     

The ANU solar thermal steam engine: performance analysis

This paper describes the results of a series of experiments that were performed to define the performance of the uniflow piston-operated valve steam engine developed by the Australian National University (ANU) for solar thermal applications. The results are fitted by least-squares regression to simple power series expressions that correlate the power output and engine inlet pressure to steam temperature, thermal power input and condenser pressure. The performance of the engine is examined by comparison with an idealized frictionless and quasi-static model. The idealized model is used to assess the relative importance of the effects of friction and non equilibrium thermodynamic conditions in the engine. The exergetic performance of the ideal engine is examined to demonstrate the fundamental limitations of this engine technology. It is concluded that high piston/cylinder forces during the first stages of expansion pose a significant barrier to the enhancement of engine efficiency through the use of higher temperatures and expansion ratios. © 1998 John Wiley & Sons, Ltd.     

车用柴油机大小涡轮相继增压系统固定转速切换的试验研究

针对某车用柴油机采用两台不同尺寸涡轮增压器的相继涡轮增压系统进行了试验研究。对柴油机分别采用大增压器、小增压器和大小增压器并联的3种方案进行外特性试验,通过分析试验结果初步确定了系统的两条固定转速切换线。对大小涡轮相继增压系统进行切换试验研究,并对切换过程中发动机转速的波动情况进行了分析,最终确定大增压器与小增压器相互切换的上下行转速分别为1380 r/min和1335 r/min,大增压器与大小两台增压器并联相互切换的上下行转速分别为1970 r/min和1955 r/min。最后,对固定转速切换的可靠性进行了试验验证。     

车用汽油机爆燃与柴油机工作粗暴之异同

分析了汽油机爆燃和柴油机工作粗暴两种非正常燃烧现象产生的机理,指出了两种现象的异同,提出了相应的防治措施。     

汽油机排放性能连续测量研究

使用AVL4000型五气分析仪连续测量了492QBW车用汽油机在多种稳定工况和启动工况下排气中有害成分CO，HC和NO的量。稳定工况试验结果表明：汽油机的转速和负荷都对CO，HC，NO排放产生影响，负荷变化对排放浓度变化的影响大于转速变化带来的影响；同时工况稳定情况下连续测量的一段时间内，各排气成分会产生一定波动，尤其是HC排放波动最大。冷启动、热启动试验结果显示，在启动过程中汽油机的CO和HC排放较高，尤其是冷启动时CO和HC排放出现峰值。     

Thermodynamic analysis of a Stirling engine including dead volumes of hot space, cold space and regenerator

This paper provides a theoretical investigation on the thermodynamic analysis of a Stirling engine. An isothermal model is developed for an imperfect regeneration Stirling engine with dead volumes of hot space, cold space and regenerator that the regenerator effective temperature is an arithmetic mean of the heater and cooler temperature. Numerical simulation is performed and the effects of the regenerator effectiveness and dead volumes are studied. Results from this study indicate that the engine net work is affected by only the dead volumes while the heat input and engine efficiency are affected by both the regenerator effectiveness and dead volumes. The engine net work decreases with increasing dead volume. The heat input increases with increasing dead volume and decreasing regenerator effectiveness. The engine efficiency decreases with increasing dead volume and decreasing regenerator effectiveness.     

The effect of displacer material on the performance of a low temperature differential Stirling engine

In this study, a gamma‐type low temperature differential Stirling engine was designed and manufactured. The displacer and piston of the engine were concentrically situated to each other. The engine was tested by using a liquefied petroleum gas burner at laboratory conditions. The working fluid was ambient air at atmospheric pressure. Test procedure intended to investigate the speed‐torque and speed‐power characteristics of the engine depending on the hot‐end temperature. Two different displacers made of aluminum alloy and medium density fiberboard were used. The maximum torque and power obtained were 0.166 Nm at 125 rpm speed and 3.06 W at 215 rpm speed, respectively, at 160 °C hot‐end temperature with medium density fiberboard displacer. Copyright © 2011 John Wiley & Sons, Ltd.     

直喷式二冲程柴油机超细颗粒物排放特性的试验研究

研究了直喷式二冲程柴油机的超细颗粒物排放特性,考察了负荷、转速、喷油嘴孔径以及燃料对排气中超细颗粒物数量浓度以及质量浓度的影响。研究结果表明:在不同的工况下,超细颗粒物的数量浓度和质量浓度没有明显的相关性;随着负荷的增大,排气中超细颗粒物的质量浓度增大,而数量浓度不一定增大;在低负荷时,排气中颗粒物数量浓度在450r/min时明显高于750 r/min,高负荷时则相反;在选择喷油嘴时,喷孔小的超细颗粒物排放水平不一定好;柴油中加入一定量的DMC,则排气中颗粒物数量浓度在低负荷时明显高于柴油,高负荷时低于柴油;而质量浓度明显低于柴油。