共查询到20条相似文献,搜索用时 15 毫秒
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液体除湿空调中除湿剂再生过程的效率和稳定决定整个系统运行效率和稳定性.对空气与除湿溶液质量流量之比、除湿溶液温度、除湿溶液的溶质浓度对除湿溶液再生系统性能的影响进行了探讨. 相似文献
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《热能动力工程》2017,(9)
正A new technology for utilizing the coal energy has been developed in Japan.It can have much higher power generating efficiency than a conventional coal fired thermal power plant while still keeping the carbon dioxide emissions in check.This technology may potentially swing the global energy source back toward coal,since now coal can be burned in a much cleaner and more efficient way. 相似文献
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针对全社会对绿色动力的需求,提出一种适用于作为备用电源、游览车和微型轿车动力电源的质子交换膜燃料电池发电系统,系统具备自启动、燃料利用率高、可靠性高、结构简单等特点,文中介绍该燃电池发电系统的特点和工艺流程。 相似文献
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The fastest and yet most prudent ways of changing the output power level of a solid oxide fuel cell power plant connected to the ac-grid are explored. The operating state of the fuel cell power plant is examined in term of the concept of feasible operating area of a cell. The utilization factor of the cell stack is maintained constant in steady-state by feeding natural gas to the fuel processor at a rate proportional to the current drawn from the stack. The fluctuations of the utilization factor in the transient state due to a change in operating power level can be constrained to the allowable range by strategically controlling the current drawn by the power conditioning unit. Based on measured variables and dynamic characteristics of the fuel processor, four strategies of controlling current are compared to arrive at the strategy that results in minimum transient time for a given power change. The proposed control schemes are verified through computer simulations. 相似文献
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The operation of proton exchange membrane fuel cell (PEMFC) stacks requires careful thermal and water management for optimal performance. Appropriate placement of cooling plates and appropriate cooling conditions are therefore essential. To study the impact of these design parameters, a two-phase model accounting for the conservation of mass, momentum, species, energy, and charge, a phenomenological model for the membrane, and an agglomerate model for the catalyst layer, is developed and solved. The model is validated for a single cell, in terms of both the local and the global current density, and good agreement is found. Four repetitive computational units are then identified for the number of single cells placed between the coolant plates: (i) one cell; (ii) two cells; (iii) three cells; and (iv) four cells. The flow fields in the single cells and the cooling plates are of a net type. The results show that there is a strong correlation between stack performance and the operating conditions/placement of the coolant plates. For the limiting case of one coolant plate between each unit cell, similar operating conditions can be achieved in every individual cell throughout the stack. As more cells are placed in between coolant plates, the stack performance drops due to an increase in temperature and decrease in water content in the membranes, unless the cooling temperature is lowered. The coolant temperature and inlet velocity need to be monitored carefully and adjusted to the operating conditions of the stack. This model can be employed for design and optimization of liquid water cooling of a PEMFC stack. 相似文献
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阐述30kW质子交换膜燃料电池(PEMFC)动力系统的研制工作;(1)建立30kW级的PEMFC测试站,达到对PEMFC控制运行以及对其性能进行测试改进的目的。(2)组装单电池并建立诊断,测试技术以及改进PEMFC膜电级(三合体)效能的技术;(3)组装5KW级,10kW级的PEMFC组功率模块,建立测试,改进其效能的技术;(4)将三台10KW级的PEMFC组功率模块进行系统集成完成30KW的PEMFC的动力系统。 相似文献
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Fuel Cell Generation System With a New Active Clamping Current-Fed Half-Bridge Converter 总被引:1,自引:0,他引:1
Jang S.-J. Chung-Yuen Won Byoung-Kuk Lee Jin Hur 《Energy Conversion, IEEE Transaction on》2007,22(2):332-340
In this paper, a new active clamping current-fed half-bridge converter is proposed, which is suitable for fuel cell power generation systems. The proposed converter is superior to conventional dc-dc converters in terms of efficiency and component utilization. The overall efficiency is estimated to be 94% at full load. 相似文献
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Masoud Rokni 《能源与动力工程:英文版》2014,(4):596-611
A SOFC (solid oxide fuel cell) cycle running on natural gas was integrated with a ST (steam turbine) cycle. The fuel is desulfurized and pre-reformed before entering the SOFC. A burner was used to combust the remaining fuel after the SOFC stacks. The off-gases from the burner were used to produce steam in a HRSG (heat recovery steam generator). The bottoming steam cycle was modeled with two configurations: (1) a simple single pressure level and (2) a dual pressure level with both a reheat and a pre-heater. The SOFC stacks in the present SOFC-ST hybrid cycles were not pressurized. The dual pressure configuration steam cycle combined with SOFC cycle (SOFC-ST) was new and has not been studied previously. In each of the configuration, a hybrid recuperator was used to recovery the remaining energy of the off-gases after the HRSG. Thus, four different plants system setups were compared to each other to reveal the most superior concept with respect to plant efficiency and power. It was found that in order to increase the plant efficiency considerably, it was enough to use a single pressure with a hybrid recuperator instead of a dual pressure Rankine cycle. 相似文献
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地铁在现在城市交通中扮演着重要作用,已成为改善城市交通压力的首选。为了保证地铁运行的可靠性,提出了基于新型燃料电池供电的地铁供电系统,并通过仿真分析了燃料电池系统的动态特性,验证了燃料电池系统的可靠性。 相似文献
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以燃料重整的固体氧化物燃料电池发电系统为研究对象,通过数值模拟方法对固体氧化物燃料电池发电系统的性能、(火用)损、(火用)效率以及多变量运行参数优化进行了分析。研究结果表明:重整反应中燃料利用系数、电池工作温度、水碳比、电堆电流密度等参数对系统性能影响显著;电堆工作在不同电流密度下都有其对应的最佳工作温度、最佳燃料利用系数工况点;水碳比会改变重整反应产氢量,从而影响电化学反应速率,空气加热器的(火用)损所占份额最大;优化后的系统效率及(火用)效率为0.480 9和0.462 6,效率提升约4%。 相似文献
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为了在有毒、易爆、高温、高压等环境中快速准确检测液体液位,系统以STC89C51单片机为核心,采用超声波测距模块DYP-ME007,利用超声波测距原理,由STC89C51单片机控制DYP-ME007模块发射超声波,遇到被测液面反射后模块接收回波,通过单片机记录超声波经过路径所用时间,计算出超声波走过距离,从而得到液位的高度,本文完成了系统的硬件电路和软件编程的设计.经实验表明:系统测量范围在2~400 cm,测量精度1 cm,符合实际需要. 相似文献
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固体氧化物燃料电池(SOFC)是一种高效低污染的新型能源。建立了以天然气为燃料的固体氧化物燃料电池和燃气轮机(GT)联合发电系统的计算模型,并对具体系统进行计算。结果表明:SOFC与GT组戍的联合发电系统,发电效率可达68%(LHV);加上利用的余热,整个系统的能量利用率可以超过80%。文中还分析了SOFC的工作压力、电流密度等参数对系统性能的影响,提高工作压力,可以增加电池发电量,提高系统的发电效率;而电流密度的增大将使SOFC及整个系统的发电量降低。 相似文献
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This paper intends to propose a novel control algorithm for utilizing a polymer electrolyte membrane fuel cell (PEMFC) as a main power source and batteries as a complementary source, for hybrid power sources for distributed generation system, particularly for future electric vehicle applications. The control, which takes into account the slow dynamics of a fuel cell (FC) in order to avoid fuel (hydrogen and air) starvation problems, is obviously simpler than state machines used for hybrid source control. The control strategy lies in using an FC for supplying energy to battery and load at the dc bus. The structure is an FC current, battery current, and battery state-of-charge (SOC) cascade control. To validate the proposed principle, a hardware system is realized by analogical circuits for the FC current loop and numerical calculation (dSPACE) for the battery current and SOC loops. Experimental results with small-scale devices (a 500 W PEM FC and 33 Ah, 48 V lead-acid battery bank) illustrate the excellent control scheme during motor drive cycles. 相似文献
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本文着眼于产业化实际应用场景,基于20KW固体氧化物燃料电池系统进行建模,并展开系统敏感性分析.敏感性分析范围包括:燃料进口流量对系统性能的影响、汽碳比对系统性能的影响、过量空气系数(λ)对系统性能的影响、燃料利用率对系统性能的影响、电流密度对系统性能的影响、电堆入口温度对系统性能的影响.该工作为系统实际运行及优化提供... 相似文献