新风负荷在建筑热负荷中占有很高的比例。为了高效处理新风负荷，研究人员设计出了一种基于固体除湿的热泵新风机组。为了进一步提高该新风机组的性能，本文研究了复合硅胶在基于固体除湿的热泵新风机组中的应用。首先对固体除湿的核心部件干燥剂涂层进行了研究，实验表明，复合硅胶涂层（CSGC）的吸附速率和平衡吸水量均是硅胶涂层（SGC）的2倍以上。此后，建立了固体除湿热泵新风实验台，分别对基于SGC和CSGC的热泵新风机性能进行了测试。结果表明，在夏季工况下，与基于硅胶涂层的固体除湿热泵新风机组（SGFU）相比，基于复合硅胶的固体除湿热泵新风机组（CSGFU）的平均除湿量和COP分别提高了15%和30%。在冬季工况下，与SGFU相比，CSGFU的平加湿量和COP分别增加了42%和17%。在切换周期为3分钟，压缩机频率为40rps的最佳运行参数下，CSGFU在夏季工况下的COP可达7.6。在不同夏季工况下的实验结果表明，在较高的室外含湿量和温度下，CSGFU和SGFU具有较高的COP和除湿率。 

为了减少传统污泥处理方法对环境的影响，并更有效地利用污泥中的能量，我们提出了一种基于污水污泥气化炉（SSG）、固体氧化物燃料电池（SOFC）、超临界二氧化碳循环（S-CO₂）和有机郎肯循环（ORC）的耦合系统。从污泥气化中获得的清洁合成气与 CH₄ 混合后首先被燃料电池利用。燃料电池排出的废气在后燃烧室中充分燃烧，然后进入由 S-CO₂ 和 ORC 组成的底部循环系统发电。为了解该系统的性能，对该项目进行了热力学和经济学分析。通过对耦合系统的热力学和经济学分析，得出以下结论：该系统的发电量为 37.34 兆瓦，放能效率为 55.62%，净电能效率为 61.48%。气化炉和 SOFC 是主要的耗能设备，占总耗能的 62.45%。新型系统的建设投资仅需 6.13 年即可收回，项目在 20 年的寿命期内可获得 17723.82 千美元的净现值。上述结果表明，新型耦合系统在能源利用和经济性方面具有更好的性能。

燃煤电厂是温室气体排放的主要来源。燃烧后碳捕集技术是一项很有前景的CO₂减排方式，但其捕集过程中的高热量需求是难以承受的。为解决这一问题，本研究将太阳能热能、燃烧后碳捕集与燃煤发电系统耦合集成，利用太阳热能来满足碳捕集过程的热量需求，从而避免电厂因自身驱动CO₂捕集所造成的发电损失。此外，将MgO吸附剂碳酸化反应放热整合到燃煤发电蒸汽朗肯循环中，通过替代汽轮机的部分抽汽用来加热给水，进一步提高了系统的发电量。将设计系统的性能与自驱动CO₂捕集燃煤电厂和光伏发电组成的参考系统相比，设计系统的碳捕集率可达 86.5%，发电量提高了 9.8%。在变工况的条件下，对系统的运行策略实施了优化，选取典型日分析，CO₂减排量相较于之前增加了11.06%。这项工作展示了一种将化石燃料和可再生能源相结合从而实现燃煤发电系统低碳排放和高效发电的方法。

利用低品位热能驱动的功冷并供（CCP）系统有望提高能源利用效率。本文提出了一种将再生有机朗肯循环（RORC）和吸收式制冷机在冷、热流体两侧集成的CCP系统，并基于热量流法建立了系统模型，完整考虑了非线性传热和热功转换约束，实现了系统性能的准确模拟。变工况性能模拟结果表明冷却水和ORC工作流体的入口温度和流速对系统性能影响显著，且由于部件传热能力有限，偏离额定工况较远时模拟计算不可行，凸显了在系统建模中考虑传热约束的重要性。此外还进行了最小化总热导的设计优化，热流体入口温度从100 ℃ 提高到 130 ℃，质量流量从 10 kg s^-1 提高到 30 kg s^-1时，RORC 效率分别提高 7.9% 及降低12.4%，表明了平衡系统成本和性能的必要性。

在能耗、(火用)和经济性分析的基础上，提出了一种带经济器的双温 CO₂制冷系统，并与传统的双温 CO₂制冷系统进行了比较。采用遗传算法多目标优化方法，以 COP、(火用)损失和总经济成本为目标函数，寻找两个系统的最佳设计条件。得到了不同环境温度下的Pareto前沿。采用与理想解决策方法相似的顺序优先技术确定最优状态点。仿真结果表明，在不同环境温度下，引入经济器可以提高双温 CO₂制冷系统的 COP、降低火用损失和总经济成本。此外，经济分析还考虑了二氧化碳排放成本和电价的影响。结果表明，随着 CO₂排放成本和电价的增加，两种制冷系统的小时经济成本都在增加，但带经济器的双温 CO₂制冷系统的小时经济成本始终低于传统的双温 CO₂制冷系统。

The standing-wave thermoacoustic engines (TAE) are applied in practice to convert thermal power into acoustic one to generate electricity or to drive cooling devices. Although there is a number of existing numerical researches that provides a design tool for predicting standing-wave TAE performances, few existing works that compare TAE driven by cryogenic liquids and waste heat, and optimize its performance by varying the stack plate spacing. This present work is primarily concerned with the numerical investigation of the performance of TAEs driven by cryogenic liquids and waste heat. For this, three-dimensional (3-D) standing-wave TAE models are developed. Mesh- and time-independence studies are conducted first. Model validations are then performed by comparing with the numerical results available in the literature. The validated model is then applied to simulate the standing-wave TAEs driven by the cryogenic liquids and the waste heat, as the temperature gradient ΔT is varied. It is found that limit cycle oscillations in both systems are successfully generated and the oscillations amplitude is increased with increased ΔT. Nonlinearity is identified with acoustic streaming and the flow reversal occurring through the stack. Comparison studied are then conducted between the cryogenic liquid-driven TAE and that driven by waste heat in the presence of the same temperature gradient ΔT. It is shown that the limit cycle frequency of the cryogenic liquid system is 4.72% smaller and the critical temperature ΔT_cri =131 K is lower than that of the waste heat system (ΔT_cri=187 K). Furthermore, the acoustic power is increased by 31% and the energy conversion efficiency is found to increase by 0.42%. Finally, optimization studies on the stack plate spacing are conducted in TAE system driven by cryogenic liquids. It is found that the limit cycle oscillation frequency is increased with the decreased ratio between the stack plate spacing and the heat penetration depth. When the ratio is set to between 2 and 3, the overall performance of the cryogenic liquid-driven TAE has been greatly improved. In summary, the present model can be used as a design tool to evaluate standing-wave TAE performances with detailed thermodynamics and acoustics characteristics. The present findings provide useful guidance for the design and optimization of high-efficiency standing-wave TAE for recovering low-temperature fluids or heat sources.

SOFC作为新一代燃料电池，以其独特的优势成为业界的热点。为了提高能量利用率并防止重整炉内积碳，通常利用喷射器回收电池阳极排气。本文综述了喷射器SOFC中的应用，包括喷射器的设计与优化方法、喷射器性能验证实验以及喷射器在SOFC系统中的性能表现。此外，为了适应叠堆的宽功率输出特性，还介绍了扩展引射器工作范围的方法。本文得到了SOFC系统喷射器的优化设计理论，包括喷射器主要结构参数对整个系统性能的影响以及喷射器性能监控的理论模型;另一方面，证明了在SOFC系统中使用喷射器可以防止积碳问题的发生，同时对余热的回收可以提高系统的能量利用率。最后，对未来的相关研究工作提出了建议，旨在推动基于喷射器的SOFC系统在未来能提供更高、更稳定的性能。

本文对在定热源条件下两种不同工质基本有机朗肯循环 (BORC)和带回热的有机朗肯循环 (IHORC)的热力学性能和净输出功率进行研究。研究结果表明，IHORC与BORC的总㶲效率相等，但IHORC的外部㶲效率低于BORC而内部㶲效率高于BORC。以膨胀机的进口压力和温度为独立参数，以㶲效率和热回收效率为目标函数建立循环的多目标优化模型，采用NSGA-II算法得到了其Pareto最优解，在最优条件下，以R236ea为工质的IHORC和BORC循环具有最优的综合性能，其㶲效率分别为40.69% 和 41.38%、热回收效率分别为83.2% 和75.6%，而蒸发器的㶲损最大，可通过降低夹点温差和提高蒸发压力的方法减少该㶲损。

吸附式制冷系统采用低品位热能驱动和天然制冷剂，具备节能环保的优势。然而，它存在效率低和成本高的缺点。吸附式制冷系统内部热量回收是提升其制冷效率（COP）的关键。基于夹点法的分析方法有助于实现系统最优的回热方式。本文建立了吸附式制冷系统的温度-热量图和问题表并进行了夹点分析。结果表明：1）夹点位于吸附床之间，即主要回热集中于吸附床之间；2）系统的动态特性（时间因素）是回热的最大制约；3）夹点温差对系统COP的影响不显著。当驱动热源温度为90℃时，硅胶-水吸附式制冷系统经过优化回热后的COP为0.73，接近于溴化锂-水吸收式制冷系统的COP。本文采用的夹点法可适用于不同类型的吸附式制冷系统（两床型、四床型、回质型等）。

本文旨在寻找一种更通用的制冷性能分析方法，并设计一种高效的模块化水冷板制冷结构。提出了一种新的分析方法，即电流和制冷率密度分析方法，得到了通用的制冷性能计算公式。建立了考虑汤姆逊效应的热电装置有限时间热力学模型，设计了高效的水冷式热电空调的基本结构，给出了具体的计算方法。分析了输入电流密度、填充系数和传热条件对热电空调制冷性能的影响，并与风冷式热电空调制冷性能进行了比较。结果表明，在制冷温差ΔT=5 K的情况时，水冷式热电空调的最大制冷率密度为8.65 kW/m²，最大制冷系数为2.27。与ΔT=5 K相比，在ΔT=15 K时，水冷式热电空调的最大制冷率密度和最大制冷系数分别降低了27.98%和76.65%。当填充系数θ=0.43时，制冷率密度和制冷系数分别为2.57 kW/m²和1.24。搭建了热电空调实验装置，对模型进行了验证，结果表明，采用高效的水冷方式时，输入电流和制冷系数的最大值分别为4A和0.95。实验数据与理论计算结果吻合较好，证明了分析方法和冷却方式的有效性。

蒸汽压缩热泵被认为是航天热控制系统的最佳选择。蒸汽压缩热泵中的换热器是受微重力环境影响较大的部件。润滑油在微重力作用下随制冷剂进入热泵系统，润滑油的进入增加了流动的复杂性。本文在不考虑相变传热的前提下，使用FLUENT 软件研究润滑油 POE RL 68H 和制冷剂 R134a 的两相混合物在换热器中的流动和润滑油沉积；建立了油膜厚度与润滑油的比例、重力加速度、入口流速以及换热器的放置方向之间的函数关系。结果表明，随着重力加速度和润滑油含量的增加，油膜厚度将呈现符合玻尔兹曼函数的S型变化，润滑油沉积量增加；随着流速的增加，油膜的厚度将呈指数下降。

In the present study, the thermodynamic and economic performance of a combined thermodynamic cycle formed by an ORC and a Kalina cycle, which can simultaneously recover waste heat of exhaust gas and cooling water of marine engine, has been analyzed. Two typical marine engines are selected to be the waste heat source. Six economic indicators are used to analyze the economic performance of this combined thermodynamic cycle system with different marine engine load and under practical comprehensive operating condition of marine engine. The results of the present study show that the combined thermodynamic cycle system with R123 as organic working fluid has the best performance. The system with cis-butene has the worst economic performance. Under practical comprehensive operating conditions of ships, R123 has the shortest Payback Periods, which are 8.51 years and 8.14 years for 8S70ME-C10.5 engine and 5G95ME-C10.5 engine, respectively. Correspondingly, payback Periods of Cyclopentane are 11.95 years and 11.90 years. The above values are much shorter than 25 years which are the lifetime of a marine ship. Under practical comprehensive operating conditions of ships, the combined cycle system can provide output power which is at least equivalent to 25% of engine power. Considering that R123 will be phased out in near future, cyclopentane may be its good successor. Cyclopentane can be used safely by correct handling and installing according to manufacturer's instructions.

In order to provide more grid space for the renewable energy power, the traditional coal-fired power unit should be operated flexibility, especially achieved the deep peak shaving capacity. In this paper, a new scheme using the reheat steam extraction is proposed to further reduce the load far below 50% rated power. Two flexible operation modes of increasing power output mode and reducing fuel mode are proposed in heat discharging process. A 600 MW coal-fired power unit with 50% rated power is chosen as the research model. The results show that the power output is decreased from 300.03 MW to 210.07 MW when the extracted reheat steam flow rate is 270.70 t·h−1, which increases the deep peak shaving capacity by 15% rated power. The deep peak shaving time and the thermal efficiency are 7.63 h·d−1 and 36.91% respectively for the increasing power output mode, and they are 7.24 h·d−1 and 36.58% respectively for the reducing fuel mode. The increasing power output mode has the advantages of higher deep peak shaving time and the thermal efficiency, which is recommended as the preferred scheme for the flexible operation of the coal-fired power unit.

将有机朗肯循环引入传统喷射制冷（CER）系统，建立了以异丁烷为制冷剂的低品位热源驱动的冷/电联产喷射制冷（CPC-ER）系统。与循环泵消耗外部功率的CER系统相比，CPC-ER系统优势明显，在实现制冷的同时可以向外输出净功。基于热力学数学模型，对这两种系统进行了能量和㶲比较分析。结果表明，CPC-ER系统的当量COP比CER系统高41.14-71.30%，且㶲效率是CER系统的1.32-1.49倍。发生器温度高达80°C时，CPC-ER系统的膨胀功和总㶲输出都达到最大值。因此，CPC-ER系统的能源利用效率高于CER系统，并且适用于具有低品位热源的冷-电并需场所。

The objective of this paper is to understand the benefits that one can achieve for large-scale supercritical CO₂ (S-CO₂) coal-fired power plants. The aspects of energy environment and economy of 1000 MW S-CO₂ coal-fired power generation system and 1000 MW ultra-supercritical (USC) water-steam Rankine cycle coal-fired power generation system are analyzed and compared at the similar main vapor parameters, by adopting the neural network genetic algorithm and life cycle assessment (LCA) methodology. Multi-objective optimization of the 1000 MW S-CO₂ coal-fired power generation system is further carried out. The power generation efficiency, environmental impact load, and investment recovery period are adopted as the objective functions. The main vapor parameters of temperature and pressure are set as the decision variables. The results are concluded as follows. First, the total energy consumption of the S-CO₂ coal-fired power generation system is 10.48 MJ/kWh and the energy payback ratio is 34.37%. The performance is superior to the USC coal-fired power generation system. Second, the resource depletion index of the S-CO₂ coal-fired power generation system is 4.38 μPR_china,90, which is lower than that of the USC coal-fired power generation system, and the resource consumption is less. Third, the environmental impact load of the S-CO₂ coal-fired power generation system is 0.742 mPE_china,90, which is less than that of the USC coal-fired power generation system, 0.783 mPE_china,90. Among all environmental impact types, human toxicity potential HTP and global warming potential GWP account for the most environmental impact. Finally, the investment cost of the S-CO₂ coal-fired power generation system is generally less than that of the USC coal-fired power generation system because the cost of the S-CO₂ turbine is only half of the cost of the steam turbine. The optimal turbine inlet temperature T₅ becomes smaller, and the optimal turbine inlet pressure is unchanged at 622.082°C/30 MPa.