太阳能蓄热式压缩空气储能系统特性分析

为解决传统压缩空气储能系统(CAES)依赖化石燃料以及其他新型CAES透平初温受到限制的问题,提出太阳能蓄热式压缩空气储能(SHS-CAES)系统。对槽式太阳能导热油蓄热式CAES和塔式太阳能熔融盐蓄热式CAES进行热力性能分析,储电折合转化系数分别为78.65%和109.71%,太阳能折算发电效率分别为19.54%和34.43%,说明该系统可有效提高系统储电效率和太阳能利用效率;同时全面揭示系统热力特性随透平初温、储能压力和释能压力的变化规律。     

压缩空气蓄能（CAES）系统综述

介绍了一种新型的大规模蓄能技术——压缩空气蓄能（Compressed Air Energy Storage,CAES）,CAES系统响应快、容量大、成本低、寿命长,逐渐成为了全球第二大蓄能技术。根据CAES系统的容量不同,将CAES系统划分为大型CAES、小型CAES和微型CAES3种,并针对3种不同容量级的CAES,详细介绍了其组成及现状,对技术特点与难点和应用领域及场景进行了分析与概述。对CAES系统的研究方向与发展前景进行了展望。     

耦合喷射制冷的微燃机CCHP系统设计及性能分析

考虑到微燃机在夏季高温环境下性能下降导致CCHP(冷热电三联产系统)运行偏离设计工况,本文提出了利用CCHP系统烟气余热进行喷射制冷,并利用该冷量对微燃机进气进行冷却的研究思路。理论计算发现:以青岛为例,在夏季工况下,对微燃机进气进行冷却可以提高出力16.4%,提高发电效率7.5%左右;对比微燃机进气冷却前后,CCHP系统一次能源效率可提高25%左右,而系统一次能源节约率可提高3%~10%;同时系统单位发电量的CO_2排放量可降低约37%。因此,在夏季高温季节对微燃机进行进气冷却可以改善微燃机和CCHP系统运行性能。     

三种典型的CCHP经济性分析比较

CCHP系统的热电联产设备投资对系统经济性影响很大，通过对应用于特定地区的三种相同功率等级、不同电／热（冷）功率比的CCHP系统进行经济性计算分析，得出选择CCHP热电联产设备的原则。     

太阳能光伏-内燃机发电及余热利用系统热力学分析

对利用太阳能和生物质能的联合冷热电系统(CCHP)进行热力学分析。系统由内燃机和太阳能光伏电池供电，由吸收式制冷及热水系统进行余热回收。太阳能光伏电池采用五参数模型，内燃机为零维、单区模型。分析转速和压比对内燃机输出功率、排气排放物和气缸内传热的影响。结果显示：太阳能光伏电池效率为14%，日发电量500 kWh；内燃机热效率可以达到37%。转速提高后，整体CCHP电效率提高2.8%，余热利用效率提高10%。内燃机的压缩比增大后，CCHP电效率增大0.52%，整体冷热电效率几乎不变。整个CCHP系统电效率为20%，冷热电联合效率可以达到40%。     

等温压缩空气储能系统液气传热特性研究

等温压缩空气储能（I CAES）无需补燃、能源利用率高且碳排放低,在大规模储能领域具有重要应用前景。在建立喷雾的I CAES系统的液气传热模型基础上,通过数值方法分析了喷雾流量对I CAES液气传热特性的影响规律。结果表明：采用喷雾方法能够有效抑制压缩和膨胀过程的温度变化、强化液气传热并实现理想I CAES过程;增大喷雾流量能够降低压缩功耗、提高膨胀做功并降低停机储气过程压损,可提高系统指示效率和储能效率。     

基于TC-CCES的冷热电联供系统热力性能分析

为了更好地理解CO2作为储能工质在热力学方面的特性,基于跨临界压缩二氧化碳储能系统(TC CCES),结合CO2易液化的特性,采用Aspen Plus软件构建了冷热电联产(CCHP)系统热力学模型,分析了回热器热水流量、低压节流阀压降及第一级压缩机出口压力对CCES CCHP系统性能的影响。结果表明：在基础运行工况下,CCES CCHP系统电效率为41%,能量效率为1.16;当回热器热水流量、第一级压缩机出口压力变化时,系统电效率与能量效率变化趋势相反;当低压节流阀压降增大时,系统电效率和能量效率均呈下降趋势;CCES CCHP系统与TC CCES系统相比,能量利用效率提升19.50%。     

利用ORC-VCR回收压缩热的预冷式CAES系统性能分析

常规非绝热压缩空气储能（D-CAES）系统的储能过程通常采用四级以上的压缩机组以减少空气压缩功的消耗,导致产生大量的低品位压缩热直接排放到环境中,能源浪费严重。针对这一问题,本工作提出了一种采用有机朗肯循环-蒸汽压缩制冷（ORC-VCR）回收压缩热的预冷式CAES系统（ORC-VCR-CAES）,通过回收空气压缩阶段压缩机产生的压缩热来对压缩机入口空气进行预冷,可以进一步降低空气压缩功的消耗,提高系统的循环效率。对ORC-VCR-CAES耦合系统进行了热力学分析和经济性分析。结果表明,不同ORC-VCR循环工质对系统性能的影响较大,采用R152a作为循环工质的ORC-VCR-CAES系统综合性能最佳。其系统循环效率可达64.15%,比常规D-CAES系统提高了5.94%;在考虑外部废热能量输入时,ORC-VCR-CAES系统(火用)效率为51.90%,比常规D-CAES系统提高了4.81%。通过压缩热的回收有效减少了冷却器的(火用)损失,但压缩机组的(火用)损失仍然较大,是系统进一步优化的关键部件;经济性分析表明,当峰谷电价为1.26元和0.30元时,ORC-VCR-CAES系统的项目...     

天然气基CCHP与热化学溶液蓄能耦合系统研究

针对天然气CCHP(冷热电分布式)系统供能与负载在时间和强度上不匹配及变工况运行效率低下的问题,提出一种基于热化学溶液蓄能技术的新型天然气基CCHP系统。该新型系统核心部件为热化学溶液制冷/蓄冷/释冷装置,具有制冷、蓄冷与释冷三重工况。采用化工动力流程模拟软件(Aspen plus)进行热力性能计算,以热力学第一、第二定律作为评价准则进行分析,结果表明:与参比系统比较,该新型系统总能系统热效率提高了14.3个百分点,达到80.2%;制冷量提升率最高可以达到61.2%;火用效率最高可以达到33.9%,低温烟气余热回收率达到36%。该新型系统结构简单,只需将传统天然气基CCHP系统补充热化学溶液制冷/蓄冷/释冷装置即可实现,具备提高冷供应量、提高总能系统效率和深度利用低温烟气余热等优势,该系统集成方法为其它能量系统集成研究提供思路,具有较好的市场应用前景。     

压缩空气储能技术现状与发展趋势

在分析传统压缩空气储能（CAES）技术的工作原理和技术特点的基础上,介绍了压缩空气储能技术的发展,包括非绝热压缩空气储能技术（D-CAES）、绝热压缩空气储能技术（A-CAES）、液化空气储能技术（LAES）和超临界压缩空气储能技术（SC-CAES）等,并给出了评价不同系统性能的技术参数。以国际上第一座压缩空气储能电站——德国Huntorf电站的运行参数和相关情况为例,分析了D-CAES技术的应用情况;对压缩空气储能技术在美国及其他国家和地区的应用和发展现状进行分析。通过对比不同的压缩空气储能技术方案,分析了A-CAES、LAES、SC-CAES及LCES储能系统的先进性、竞争优势与不足,分析了未来CAES技术的发展趋势。     

火电厂热力系统Yong分析

应用Yong分析方法,对火电厂热力系统进行了诊断。分析了系统中各主要设备和环节的热力学完善性,找出系统中的薄弱环节,并与使用传统的热平衡法取得的结果进行了比较,为火电厂的运行优化和节能技改提供了较为科学的依据。     

Thermoeconomic analysis of a trigeneration system

In this study a trigeneration plant which produces electrical power with a natural gas fed reciprocating engine and which yields absorption cooling by making use of exhaust gases of the system has been examined. In order to use both energy and financial resources most efficiently, the thermoeconomic analysis method which gives the most accurate and easy results have been applied on the system and its components. Using this method, the amount of available energy (exergy) gained, lost and destroyed have been calculated separately for each component of the system. Taking investment and operation costs of the system into account, recommendations have been given on the subject of which parameters have to be changed in what way so that the system works more efficiently.     

Performance evaluation of a novel CCHP system integrated with MCFC,ISCC and LiBr refrigeration system

This paper proposes a novel combined cooling, heating, and power (CCHP) system integrated with molten carbonate fuel cell (MCFC), integrated solar gas-steam combined cycle (ISCC), and double-effect absorption lithium bromide refrigeration (DEALBR) system. According to the principle of energy cascade utilization, part of the high-temperature waste gas discharged by MCFC is led to the heat recovery steam generator (HRSG) for further waste heat utilization, and the other part of the high-temperature waste gas is led to the MCFC cathode to produce CO₃^2?, and solar energy is used to replace part of the heating load of a high-pressure economizer in HRSG. Aspen Plus software is used for modeling, and the effects of key factors on the system performances are analyzed and evaluated by using the exergy analysis method. The results show that the new CCHP system can produce 494.1 MW of electric power, 7557.09 kW of cooling load and 57,956.25 kW of heating load. Both the exergy efficiency and the energy efficiency of the new system are 61.69% and 61.64%, respectively. Comparing the research results of new system with similar systems, it is found that the new CCHP system has better ability to do work, lower CO₂ emission, and can meet the cooling load, heating load and electric power requirements of the user side at the same time.     

Power conditioning system for grid-connected photovoltaic system

This study develops a new control strategy for an expandable grid-connected photovoltaic (PV) system. The proposed system performs dual functions of a PV generation and an active power filter, or either one. To this end, the grid current, instead of output current of the converter, is shaped to be a sinusoidal current in phase (or opposite phase) with the grid voltage. Furthermore, its reference current is generated in multiplying the voltage loop controller output by the grid voltage waveform, and therefore non-active components analysis for harmonics elimination and reactive power compensation in the conventional design is not necessary. As a result, the algorithm is simple and easy to implement, and only one sensor for current detection plus two voltage sensors are required. Experimental results verified the effectiveness of the proposed method.     

Thermodynamic analysis of a novel energy storage system based on compressed CO2 fluid

Because of rapidly growing renewable power capacity, energy storage system is in urgent need to cope with the reliability and stability challenges. CO₂ has already been selected as the working fluid, including thermo‐electrical energy storage or electrothermal energy storage systems and compressed CO₂ energy storage (CCES) systems. In this paper, a CCES system based on Brayton cycle with hot water as the heat storage medium is proposed and analyzed. Thermodynamic model of the system is established for energy and exergy analysis. Sensitivity analysis is then conducted to reveal effects of different parameters on system performances and pursue optimization potential. At a typical transcritical operation condition, round trip efficiency is 60% with energy density of 2.6 kWh/m³. And for the typical supercritical operation condition, the round trip efficiency can reach 71% with energy density of 23 kWh/m³. High round trip efficiency and energy density, which is comparable with those of compressed air energy storage systems, thermo‐electrical energy storage (electrothermal energy storage) systems, and other CCES systems, lead to promising prospect of the proposed system. Copyright © 2017 John Wiley & Sons, Ltd.     

Thermodynamics analysis of a hybrid system based on a combination of hydrogen fueled compressed air energy storage system and water electrolysis hydrogen generator

In front of the opportunity of the rapid development of renewable energy power generation, energy storage is playing a more important role in improving its utilization efficiency. In this paper, a hybrid energy system based on combination of hydrogen fueled compressed air energy storage system and water electrolysis hydrogen generator is proposed. The superfluous renewable energy power is charged by compressing the air and/or producing hydrogen through water electrolysis. A hydrogen combustor is introduced to raise the air temperature in the discharging process. A thermodynamic model of the proposed system is built. Energy and exergy analysis found that under the design condition, the proposed system can achieve a round trip efficiency of 65.11%, an exergy efficiency of 79.23%, and an energy storage density of 5.85 kWh/m³. The exergy loss of water electrolysis hydrogen generator and hydrogen combustor rank in the top two of all components. Sensitivity analysis indicates that the outlet temperature of hydrogen combustor and specific energy consumption of water electrolysis hydrogen generator are the crucial influencing factor of system performance.     

地源热泵系统动态经济性分析

介绍地源热泵系统的基本原理,分析地源热泵技术的应用背景。利用费用现值法和年值法对地源热泵系统和空气源热泵系统的经济性进行计算,运用动态追加投资回收期公式得出地源热泵系统初投资的动态追加投资回收期。实例分析表明：地源热泵系统比传统空调系统运行费用低,具有明显的节能环保功效。     

五级自动复叠系统制冷剂组分实验研究

基于自动复叠制冷循环设计并搭建了实验系统,针对多级自动复叠制冷系统中混合工质的配比以及实际运行中循环特性的难题,利用气相色谱仪对五级自动复叠制冷系统中混合工质在各级的实际运行的成分进行了取样、检测和分析。经过多次调试,使系统达到-126 ℃的低温工况,并通过实验全面了解循环过程中各级的状态。结果发现,自动复叠制冷循环中制冷剂的配比对系统的运行压力、各级毛细管节流后的温度、各级中间换热器的换热温差等参数影响很大。研究为混合工质的运行成分分析提供了指导与建议。     

PEM fuel cell degradation effects on the performance of a stand-alone solar energy system

After comparing fresh and degraded performances of Polymer Electrolyte Membrane (PEM) based components of a hydrogen cycle with the help of computational fluid dynamics simulations, recently established stand-alone solar energy system producing hydrogen for energy storage is investigated focusing on the effects of degradation of fuel cells on the overall performance of the system. A complete model of the system has been developed using TRNSYS, and a degraded PEM Fuel Cell Subsystem has been incorporated into the model. Then, the effects of the PEM fuel cell degradation on the overall performance of the energy system are estimated. After reviewing the simulation results, the model shows that the PEM Fuel Cell degradation has a substantial impact on the overall system performance causing a system down time of approximately one month in a typical simulation year. Consequently, the stand-alone system is not capable of operating continuously for a complete year when the PEM fuel cells are degraded. Furthermore, an economic analysis is performed for a project lifetime of 25 years and the Levelized Cost of Electricity (LCE) value of the degraded system is found to be 0.08 $/kWh higher than the newly established system. Nevertheless, LCE calculations that are repeated for declining PV panel costs show that the considered hybrid system may be an economically competitive alternative to conventional diesel generators, even when the degradation of PEM based components and their regular maintenance are considered.     

闭式外腔循环太阳能墙集热效果实验研究

文章设计了闭式外腔循环太阳能墙系统,从理论和实验两方面研究太阳能墙传热传质规律。以大连市冬季为研究背景,基于对实验测温点不同时刻的持续监测,从逐时曲线中分析了不同环境下闭式外腔循环系统内部温度以及室内获得热量后室温的变化情况。结果表明,太阳能墙集热效率与太阳辐射强度密切相关,在晴朗天气下,白天部分时段单一太阳能墙就能满足采暖要求,不满足采暖要求时可以选择空气源热泵辅助采暖。