有限热源四温位不可逆吸收式制冷循环模型及性能分析

建立了热源热容量有限、综合考虑热源与环境间的热漏、热源与循环工质问的热阻以及循环内部不可逆性时的不可逆四温位吸收式制冷循环模型，并导出了循环制冷率和制冷系数间的一般关系式；利用数值算例，分析了吸收式制冷机的一般性能和优化性能，得出了热漏、内不可逆性和工质放热量分配率对循环性能的影响规律。所得结论可为吸收式制冷机的设计和优化提供一些新的理论指导。     

磁布雷顿制冷循环性能的优化分析

基于统计力学的性质推导出了顺磁系统的热力学关系,并构建了以满足居里定律的顺磁材料为工作物质的一般磁布雷顿制冷循环模型。研究了内不可逆性和传热不可逆性对循环优化性能的影响。根据该循环模型,推导出了循环的各种优化关系并深刻讨论了循环的性能特性,所得结果将有助于实际的磁制冷机的优化设计和应用。     

氨水吸收式制冷与热泵两用装置的实验分析与研究

吸收式制冷机是正向循环与逆向循环合为一体的系统，它不仅具有制冷的作用，而且稍加变动，还可作为热泵（第一类）使用。本文作者，在同一套氨水吸收式制冷装置上，解决了氨水吸收式制冷与氨水吸收式热泵之间相互转换的实际问题，分别进行了制冷与热泵（第一类）两方面的实验，得出了部分实验结果，为进一步分析两者之间的匹配关系，提供了实验依据。     

三效溴化锂吸收式制冷机的发展概况

本文综述了三效溴化锂吸收式制冷机的发展概况，介绍了三效式溴冷机新工质对、吸收循环方式、传热与传质和新型缓蚀剂的研究状况。同时，展望了三效溴化锂吸收式制冷机的发展趋势。     

磁布雷顿制冷机优化循环性能及参数设计

基于统计力学和磁工质的热力学性质,建立磁布雷顿制冷机循环新模型,探索热漏、有限速率热传导,绝热过程不可逆性和绝热时间等对循环性能的影响,应用对数平均温差及热力学分析方法,导出制冷率、性能系数的数学表式,并应用数值方法分析、评估磁布雷顿制冷循环的优化性能特性,所得结果为磁制冷机的优化设计和性能改善提供参数设计参考。     

蒸汽型溴化锂吸收式冷温水机组的设计与优化

根据溴化锂吸收式制冷机冷却负荷大的特点，本文提出了一种蒸汽型溴化锂吸收式冷温水机组的设计和优化方法，给出了所设计的６００ＫＷ制冷量冷温水机组的工作参数和技术指标，并通过与蒸汽单效溴化锂吸收式制冷机的性能比较和对本机组的节能效益和有效能利用率分析，认为蒸汽型溴化冷温水机组是一种值得大力推广的机型。     

吸收式制冷机的新发展

吸收式制冷机对于环保和平衡负荷都很有用.本文介绍了吸收式制冷机的新发展.其内容包括提高循环COP值和扩大功能的新循环.新循环有高温发生器的复叠驱动;附有发电的制冷循环;非保温热输送和浓度差蓄能.     

单效溴化锂吸收式制冷循环吸收特性与工况关系的研究

以单效溴化锂吸收式制冷机为研究对象,对溴化锂水溶液的热力性质参数进行了计算机模拟。通过模拟计算,得到了求解溴化锂水溶液热力参数的较为精确的计算方法。溴化锂吸收式制冷机是以水为制冷剂,溴化锂为吸收剂,通过消耗热能来实现制冷目的的。通过对单效循环的仿真模拟计算,实现了对机组在不同工作工况下的性能预测。为进一步利用数字和模拟手段深入研究溴化锂吸收式制冷机组奠定了良好的基础。     

不可逆布雷顿制冷循环的性能优化

基于不可逆布雷顿制冷循环模型,导出循环制冷率和性能系数之间优化关系所应满足的方程,利用数值解,研究内不可逆性和传热不可逆性对优化性能的影响.讨论了循环的各种优化性能,所得结果对实际制冷系统的优化设计有一定的指导意义.     

吸收式制冷机典型特性DOE-2模型的修正及其应用

在冷热电等多功能联产子系统中，溴化锂吸收式制冷机是常用的供冷设备，DOE-2关于冷源特性模拟的经验模型是分析其典型变工况特性的解析方法之一。分析了吸收式制冷机特性DOE-2模型的适用范围。为扩展吸收式制冷机特性DOE-2模型的适用范围，以双效蒸汽型溴化锂吸收式制冷机为例，对DOE-2模型中的能量消耗特性引入冷媒水温度变化的修正，给出一个DOE-2模型的修正式，经与实际数据和理论模型对比证明其合理有效。在能源动力系统中的应用案例表明，修正的DOE模型可用于快速分析吸收式制冷机定水流量时的典型变工况特性，对故障诊断、性能预测等具有理论意义，也便于工程上初步进行系统优化配置和经济运行。     

Optimization study of the compression/absorption cycle

For each external situation optimum working conditions for the compression/absorption cycle can be found. The improvement in cycle performance which is gained by optimizing the temperature gradient in the absorber is considerable, particularly for situations with small external temperature gradients. Theoretically, the external and internal temperature gradients should be equal to maximize the cycle performance. The introduction of a solution loop, however, changes this and the optimum internal temperature gradient is always larger than the external gradients. The optimum point of operation is found by studying the changes in the compressor and pump and the heat loss obtained in the solution heat exchanger with the working conditions. A comparison of a compression/absorption cycle, using NH₃-H₂O, and a compression cycle working with pure R12, always results in a higher coefficient of performance for the former. The capacity of the NH₃-H₂O system is also considerably higher.     

Thermodynamic assessment of an integrated molten carbonate fuel cell and absorption refrigerator hybrid system for combined power and cooling applications

A hybrid system is proposed to harvest the waste heat released in MCFC through integrating an absorption refrigerator as a bottoming cycle. A thermo-electrochemical model is used to describe the main irreversible losses in the system. The operating current density interval of the MCFC that enables the bottoming absorption refrigerator to effectively cool is determined. Numerical expressions for the equivalent power output and efficiency are derived to evaluate the performance of the hybrid system under different operating conditions. Compared to the stand-alone MCFC, the maximum power density and the corresponding efficiency of the hybrid system are found to have increased by 3.2% and 3.8%, respectively. The general performance characteristics and optimum operating regions for the hybrid system are revealed. Comprehensive parametric analyses are conducted to investigate how the hybrid system performance depends on various physical properties and working conditions such as working fluid internal irreversibility inside the absorption refrigerator, heat transfer coefficients, some thermodynamic losses related parameters, and the operating current density, temperature and pressure of the MCFC.     

Assessment of condensation heat transfer correlations in the modelling of fin and tube heat exchangers

This is the second paper of a series that assesses the performance of a refrigeration system model by means of cycle parameters. In this case, the condensation temperature is the parameter to study and it is focused on fin and tube condensers. It also studies the influence of the heat transfer models on the estimation of this refrigeration cycle parameter and different correlations for the heat transfer coefficients have been implemented in order to characterise the heat transfer in the heat exchangers. The flow inside the heat exchangers is considered one-dimensional as in previous works. In the cycle definition, other submodels for all the cycle component have been taken into account to complete the system of equations that characterises the behaviour of the refrigeration cycle. This global system is solved by means of a Newton–Raphson algorithm and a known technique called SEWTLE is used to model the heat exchangers. Some experimental results are employed to compare the condensation temperatures provided by the numerical procedure and to evaluate the performance of each heat transfer coefficient. These experimental results correspond to an air-to-water heat pump and are obtained by using R-22 and R-290 as refrigerants.     

Mapping of optimum operating condition for LiBr–water refrigeration cycles

In this work, optimum operating condition maps are generated covering wide ranges of refrigeration and sink temperatures for single- and double-effect LiBr–water vapour absorption refrigeration cycle. These optimum condition maps will be useful to choose optimum operating conditions while designing LiBr–water cycle for desired applications. Methodology for generating such maps is discussed in detail, which can also be used for other absorption refrigeration cycles with various working fluids. Three configurations of LiBr–water absorption refrigeration cycles, single effect, double-effect series flow and double-effect parallel flow, are analysed with the most accurate thermodynamic property correlation available in the literature. Sensitivity of cycle performance to various operating variables such as generator, absorber and condenser temperatures is determined. Second law analysis shows that when a higher temperature heat source is available, double-effect cycles are more effective over single effect as they have higher coefficient of performance.     

Performance of absorption refrigeration cycle at maximum cooling rate

The influence of irreversibility of finite-rate heat transfer on the performance of an absorption refrigerator is investigated using an endoreversible cycle model with continuous flow. The cooling rate is adopted as an objective function for refrigerator optimization. The maximum cooling rate and the corresponding coefficient of performance are derived. The optimal performance with respect to heat transfer areas of the refrigerator is analysed. In addition, certain significant conclusions are reached.     

Cycle analysis of an air-cooled LiBr/H2O absorption heat pump of parallel-flow type

A gas-fired absorption heat pump with cooling capacity of 2 RT was analysed as an air-conditioner for domestic use during the summer. The absorption heat pump considered was an air-cooled, double-effect, LiBr/H₂O system of parallel-flow type. The performance of the absorption heat pump in the cooling mode of operation was investigated through cycle simulation to obtain the system characteristics depending on the inlet temperature of air to the absorber, the working solution concentrations, the solution distribution ratio of the mass of solution into the first generator to the total mass of solution from the absorber, and the LTDs (leaving temperature differences) of the heat-exchanging components. When the predicted results were compared with the measured data for similar design conditions, reasonable agreement was observed. The optimum design and operating conditions of an air-cooled absorption system are suggested based on this cycle simulation analysis.     

套管式冷凝器优化分析及应用

以热流密度为目标函数对套管式冷凝器进行优化分析，得出在不同套管直径下的热流密度最大值与最佳内管直径的关系，将其应用于套管式冷凝器的设计，为选取最佳方案提供一种方便的分析方法。     

Profit rate performance optimization for a generalized irreversible combined refrigeration cycle

Finite-time exergoeconomic performance of a Newtonian heat transfer law system generalized irreversible combined refrigeration cycle model with finite-rate heat transfer, heat leakage and internal irreversibility is presented in this paper. The operation of the generalized irreversible combined refrigeration cycle is viewed as a production process with exergy as its output. The performance optimization of the cycle is performed by taking profit as the objective. The optimal profit rate, optimal COP (coefficient of performance), as well as the relation between the optimal profit rate and COP of the cycle are derived. The focus of this paper is to obtain the compromise optimization between economics (profit rate) and the energy utilization factor (COP) for the cycle, by searching the optimum COP at maximum profit rate, which is termed as the finite time exergoeconomic performance bound. Moreover, the effects of various factors, including heat leakage, internal irreversibility and the price ratio, on the profit rate performance of the cycle are analysed by detailed numerical examples.     

Effect of Heat Transfer on the First and Second Law Efficiency Analysis and Optimization of an Air-standard Atkinson Cycle

In this paper, the first and second-law analysis for the thermodynamic air-standard Atkinson cycle with an account for heat transfer is performed using finite-time thermodynamics. In order to have more accurate evaluations, the effects of thermodynamic and design key parameters on the performance characteristics of Atkinson cycle are shown. Further, artificial neural network and imperialist competition algorithm are employed to predict and optimize the net work output value versus the minimum cycle temperature and also the compression ratio. The results obtained show that the heat loss is an effective factor of the performance of the cycle and it should be considered in the analysis and comparison of practical internal combustion engines.