【作者】 蒋润花；

【导师】 杨晓西；

【作者基本信息】 华南理工大学 ， 化学工程， 2014， 博士

【摘要】 分布式冷热电联供系统以其高的能源利用率和环保优势成为我国节能减排的首选技术之一，但现有的冷热电联供系统存在变工况运行性能差、中低品位变温余热无法高效回收利用等难题，导致系统热力性能与经济性恶化。因此，研究系统全工况性能调控方法和动力余热驱动除湿循环对提高分布式冷热电联供系统能源利用效率意义重大。本文根据各单元设备的全工况模型，组合成具有特定功能的冷热电联供系统模型，提出改善系统变工况性能的调控方法，对分布式冷热电联供系统性能影响因素进行了定量化的理论分析，建立了冷热电联供系统优化模型。研究了与各种冷热电负荷需求相适应运行模式，采用一次能源利用率和相对节能率作为评价准则，分析了冷电比、发电效率和功率等因素对系统性能的影响，采用蓄能、电压缩式制冷或补燃对系统性能进行调控。结果表明，冷电比是影响系统性能的主要因素，对于“以电定冷”模式，随着冷电比增加，系统一次能源利用率增大，相对节能率先增大后减少，存在着最佳冷电比；对于“以冷定电”模式，随着冷电比增加，系统一次能源利用率和相对节能率先增大后减少，达到最佳冷电比时，系统处于最优运行状态点。本文对内燃机冷热电联供系统性能进行了深入的理论与实验研究，在单元设备和用户冷热电负荷动态特性基础上，分析了变工况条件下系统性能下降的原因，内燃机输出功率改变，制冷机组性能改变，导致整个系统性能发生变化，当内燃机输出功率为40kW，系统性能最佳，验证了冷热电联供系统全工况优化模型的准确性。研究了内燃机冷热电联供系统各单元设备中可用能的利用状况，采用“黑箱”模型对系统进行分析，柴油机发电过程损失最大，换热器的损失最小，且随着内燃机输出功率的增加，各设备过程的损失增加。针对高温高湿地区的气候特点，研究了动力余热驱动的氯化锂溶液吸收式除湿过程及其对地域性分布式冷热电联供系统性能的影响，探悉了冷热电联供系统正逆耦合循环和吸收式除湿逆循环间耦合机理，分析了冷热电联供系统和余热负荷驱动吸收式逆循环的能量输入或输出的比例调控和变工况能量特性。实验研究了利用内燃机缸套水为再生热源液体吸收式除湿特性及其对冷热电联供系统性能的影响，分析了缸套水热负荷以及LiCl溶液吸收式除湿机组变工况特性，探寻了提高冷热电联供系统热力性能的方法。结果表明，带除湿的冷热电联供系统的一次能源利用率相对于常规冷热电联供系统提高了15%左右，相对节能率提高了20%左右。采用全工况性能调控方法和低品位余热驱动吸收式除湿技术，设计了1200kW级工业园区冷热电联供系统，提出了多种正逆循环、多个热力系统耦合集成方案，综合考虑热力性能和经济性能，采用优先考虑系统全工况性能，兼顾用户侧冷热电需求的主动蓄能新思路，带蓄能的冷热电联供系统集成方案优势明显，其一次能源利用率达81.7%，节能率达34.7%，作为工业园区推荐方案。根据冷热电联供系统实际运行测试数据，分析了冷热电联供系统热力性能，系统的一次能源利用率达到77.6%，相对节能率达到25.3%。验证了系统集成与全工况性能调控理论和方法的正确性，为分布式冷热电联供系统集成方案提供理论与实验依据。更多还原

【Abstract】 Distributed energy system with its high energy efficiency and environmental protectionadvantages become one of the preferred technology for energy conservation and emissionreduction. Off-design performance was poor, and waste heat of low grade temperature cannotbe efficiently recycled, it leads to thermal performance and economy of CCHP systemdeteriorated. Therefore, the control methods of off-design performance and dehumidificationcycle driven by waste heat of CCHP system have been investigated in this paper, it is greatsignificance to to improve distributed CCHP system energy efficiency.According to the off-design model of each unit, the model of combined cooling heatingand power cogeneration system with specific features has been explored. The control methodsof improving the system off-design performance were proposed. The influence factors ofCCHP system have been analyzed. The optimization model of CCHP system established. Theoperation modes of all kinds need adopting of cold, heat and power load was investigated.The evaluation criterias of primary energy rate and relative energy saving ratio were adopted.The impact of cooling to power ratio, the efficiency of power generation and power on theCCHP system was analyzed. The performance of CCHP system was controlled by energystorage, electric compression refrigeration or afterburning. The results showed that, thecooling to power ratio was the main factor affecting performance of CCHP system. With thecooling to power ratio increasing, the primary energy rate increased, and relative energysaving ratio increased firstly and then decreased following the cooling load mode, there wasoptimal cooling to power ratio. With the cooling to power ratio increasing, the primary energyrate and relative energy saving ratio increased firstly and then decreased following the powerload mode, there was optimal running point.Combined the off-design model and the experimental platform, the theoretical andexperimental performance of the internal combustion engine CCHP system has beeninvestigated.based on dynamic characteristic of user’s need and each unit. The resons of poorperformance was investigated. The best working state of CCHP system had been explored,when power of combustion engine was40kW. In order to further study the available energyutilization of internal combustion engine CCHP system. Exergy analysis for CCHP systemhad been researched adopting the "black box" model. The distribution and reasons of exergyloss were analyzed. The exergy loss of combustion engine was the largest, and the exergy lossof heat exchange was the least. With output power increasing, the exergy loss of each unitincreased. Since low grade heat would not to be efficiently recovered and the damp climaticcharacteristics of southern China area, low grade waste heat effective utilization mechanismof CCHP system were studied. LiCl solution absorption dehumidification unit was driven bylow grade heat. The experiment platform of dehumidification unit driven by low grade heat ofinternal combustion engine cylinder jacket water was built. The low grade heatdehumidification mechanism and experimental research had been carried out. The off-designperformance of LiCl solution absorption dehumidification unit was investigated in thispaper.The results show that, compared to conventional CCHP system, the primary energy rateof CCHP system with dehumidification increased by about15%, relative energy saving ratioincreased by20%.All kinds of integrated schemes of industrial park1200kW CCHP system wereresearched, which combined internal combustion engine, absorption refrigeration, absoptiondehumidification, energy storage and other integration technologies. Considering thetechnology and economy, the scheme with ice storage had obvious advantages. As therecommended scheme, its primary energy utilization rate was81.7%, relative primaryenergysaving rate was34.7%. According to the actual test data of CCHP system, thermalperformance of CCHP system was analyzed. The primary energy rate was77.6%, and relativeprimary energy saving rate was25.3%. It verified control theory and method correctness ofsystem integration and performance.更多还原