不可逆吸收式热泵循环的基本优化关系及性能分析

在恒温热源内可逆四热源吸收式热泵循环的基础上，建立了线性(牛顿)传热定律下考虑泵热空间到环境热源的热漏、工质的内部耗散以及工质与外部热源间的热阻损失的不可逆吸收式热泵循环模型。导出了总换热面积一定的条件下循环的泵热率和泵热系数的基本优化关系、最大泵热率和相应的泵热系数、最大泵热系数和相应的泵热率、以及循环中最佳工质工作温度和最佳换热面积分配关系；并通过数值算例分析了循环参数对循环最优性能的影响规律。     

吸收式热变换器循环热力学模型及优化应用

建立了热源热容量有限时,综合考虑传热热阻、热源与环境的热漏以及循环内不可逆性时的实际四温位不可逆吸收式热变换器循环模型,导出了泵热率和泵热系数的一般特性关系;利用单效溴化锂吸收式热变换器机组的工程数值计算方法,与热力学模型预测结果进行了对比分析,佐证了所建立的热力学模型及导出的特性关系的正确性;并探讨了不同工况时的循环性能,以及通过减小循环内不可逆性、热源热漏和对换热器总传热面积进行优化分配后循环性能可能提高的幅度。     

热阻、热漏和内不可逆性对两级吸收式制冷循环性能的影响

建立考虑工质与外部热源间的传热损失、内不可逆性损失及外部热源热漏损失的不可逆两级吸收式制冷循环模型,给出制冷系数和制冷率的一般关系。在6个换热器总热导率一定时,对循环性能进行优化,导出循环制冷率和制冷系数的基本优化关系,并得到制冷率和制冷系数的极值。通过数值算例,分析热阻、热漏和内不可逆性损失对循环性能的影响规律。     

内可逆四热源吸收式热变换器的基本优化关系及其性能分析

应用内可逆四热源吸收式热变化器循环模型，分析热变换器受传热不可逆性影响时的基本性能。导出了牛顿传热定律下循环的比泵热率和泵热系数的基本优化关系以及工质的最佳工作温度和传热面积的最佳分配关系。由此讨论了循环的各种优化性能，并通过数值算例，得出循环参数对循环特性的影响规律。所得结果对实际四热源吸收式热变换器的优化设计具有一定指导意义。     

基于分析的不可逆变温热源四温位吸收式热变换器循环生态学性能

基于分析的观点,建立变温热源、不可逆、四温位吸收式热变换器的生态学目标,导出其生态学目标、泵热系数、泵热率和基本特性参数的一般关系式。该模型考虑热源热容量有限、热源与环境间的热漏、内部工质循环的不可逆以及热源与循环工质间的传热热阻。给出热导率和传热面积优化分配后循环的生态学性能,并进一步分析基于能量分析的生态学目标和基于分析的生态学目标性能的区别。     

q∝△(T-1)的不可逆吸收式制冷系统的优化

以内可逆吸收式制冷循环模型为基础，建立一个不可逆吸收式制冷循环的模型，该模型的热传导规律为q∝△（T^-1），包括低温热源到制冷空间的热漏及工质内部耗散，工质与外部热源间的有限热传导率的不可逆性，并用于导出制冷系数与制冷率的关系及在优质状态下的传热面积的分配关系。确定了在q∝△（T^-1）规律不可逆吸式制冷系统的主要参数的实际优选范围。     

不可逆卡诺热泵的有限时间热力学最优化

本文在考虑工质与热源间热阻损失的内可逆卡诺热泵模型基础上，用一常数项表示热源间的热漏，用一带系数项表示循环中除热阻和热漏外的其余所有不可逆性（如摩擦,涡流,非平衡等），建立了一个不可逆定常态能量转换卡诺热泵模型，并对此不可逆热泵模型进行有限时间热力学分析，导出了供热率和供热系数之间的优化关系。由此模型可准确描述各种不可逆性对热泵性能的影响，能对实际热泵的工作性能起到精确的指导作用．     

线性唯象传热定律下不可逆四热源制冷循环最优性能

在恒温热源内可逆四热源吸收式制冷循环的基础上，考虑环境热源到制冷空间的热漏、工质的内部耗散以及工质与外部热源问的热阻损失，建立传热服从线性唯象定律的不可逆吸收式制冷循环的模型，导出循环的制冷率和制冷系数的基本优化关系、最大制冷系数及相应的制冷率和最大制冷率及相应的制冷系数，给出了最佳换热面积，并通过数值计算分析了设计参数对循环的制冷率、制冷系数的影响。所得结果对实际吸收式制冷机的设计和运行有一定的指导意义。     

导热规律服用q∞（△T）^n广义不可逆卡诺热机的最优性能

考虑工质与热源间热阻损失,用一常数项表示热漏损失和常系数项表示循环中除热阻和热漏外其余不可逆性，建立不可逆卡诺热机模型。基于另一类较为普遍的导热规律Q∞（△T）^n，导出热机的功率和效率最佳特性关系，由详细数值计算分析了热漏、内不可逆性和导热规律的影响特点。     

变温热源不可逆KCS-34循环的有限时间热力学优化

应用有限时间热力学理论建立了变温热源不可逆KCS-34循环模型,该模型考虑了热源和内部循环工质之间的传热热阻、膨胀机和循环泵的不可逆性、有限热容率热源和有限换热面积;分析了循环工质质量流率、蒸发器出口循环工质干度和冷凝器换热面积比对循环净功率、效率的影响,得到了循环净功率和热效率之间的关系;发现在各部件换热面积一定时,存在最佳的蒸发器出口循环工质干度使得循环效率最大,存在最佳的循环工质质量流率使得循环净功率最大;在蒸发器和冷凝器换热面积变化而总换热面积一定时,存在最佳的冷凝器换热面积比分别使得循环净功率或效率最大。所得结果对KCS-34循环的优化设计有一定的指导意义。     

Irreversible absorption heat-pump and its optimal performance

On the basis of an endoreversible absorption heat-pump cycle, a generalized irreversible four-heat-reservoir absorption heat-pump cycle model is established by taking account of the heat resistances, heat leak and irreversibilities due to the internal dissipation of the working substance. The heat transfer between the heat reservoir and the working substance is assumed to obey the linear (Newtonian) heat-transfer law, and the overall heat-transfer surface area of the four heat-exchangers is assumed to be constant. The fundamental optimal relations between the coefficient of performance (COP) and the heating-load, the maximum COP and the corresponding heating-load, the maximum heating load and the corresponding COP, as well as the optimal temperatures of the working substance and the optimal heat-transfer surface areas of the four heat-exchangers are derived by using finite-time thermodynamics. Moreover, the effects of the cycle parameters on the characteristics of the cycle are studied by numerical examples.     

Performance optimization of an irreversible four-heat-reservoir absorption refrigerator

On the basis of an endoreversible absorption refrigeration cycle model with linear phenomenological heat transfer law of Q∝Δ(T⁻¹), an irreversible four-heat-reservoir cycle model is built by taking account of the heat resistance, heat leak and irreversibilities due to the internal dissipation of the working fluid. The fundamental optimal relation between the coefficient of performance (COP) and the cooling load, the maximum COP and the corresponding cooling load, as well as the maximum cooling load and the corresponding COP of the cycle coupled to constant-temperature heat reservoirs are derived by using finite-time thermodynamics. The optimal distribution relation of the heat-transfer surface areas is also obtained. Moreover, the effects of the cycle parameters on the COP and the cooling load of the cycle are studied by detailed numerical examples. The results obtained herein are of importance to the optimal design and performance improvement of real absorption refrigerators.     

The influence of heat resistance and heat leak on the performance of a four-heat-reservoir absorption refrigerator with heat transfer law of Q∝Δ(T)

On the basis of an endoreversible absorption refrigeration cycle model with Newton's heat transfer law, an irreversible four-heat-reservoir cycle model with another linear heat transfer law of Q∝Δ(T⁻¹) is built by taking account the heat leak and heat resistance losses. The fundamental optimal relation between the coefficient of performance (COP) and the cooling load, the maximum COP and the corresponding cooling load, as well as the maximum cooling load and the corresponding COP of the cycle with another linear heat transfer law coupled to constant-temperature heat reservoirs are derived by using finite-time thermodynamics. The optimal distribution relation of the heat-transfer surface areas is also obtained. Moreover, the effects of the cycle parameters on the COP and the cooling load of the cycle are studied by detailed numerical examples. The results obtained herein are of importance to the optimal design and performance improvement of a four-heat-reservoir absorption refrigeration cycle.     

Optimal performance of an irreversible absorption refrigerator

On the basis of endoreversible absorption refrigeration cycle model with the sole irreversibility of heat transfer between the working fluid and the heat reservoirs, an irreversible model of absorption refrigeration cycle with heat transfer law of q∝Δ(T⁻¹), which includes the heat leak from the heat sink to the cooled space and irreversibilities due to the internal dissipation of the working fluid besides the finite-rate heat transfer between the working fluid and the external heat reservoirs, is established and used to derive the relation between the optimal coefficient of performance and the cooling load and the optimal distribution of the heat-transfer surface areas of the heat exchangers. The practical optimal regions of the cycle are determined and new bounds of the primary performance parameters are given. A numerical example is provided to illustrate the performance characteristic of endoreversible and irreversible cycles.     

热漏对内可逆四热源制冷系统的影响

在恒温热源内可逆四热源吸收式制冷循环的基础上，建立不可逆吸收式制冷循环的模型，考虑环境热源到制冷空间的热漏以及工质与外部热源间的热阻损失，导出牛顿定律下循环的制冷率和制冷系数的基本优化关系、最大制冷系数及相应的制冷率和最大制冷率及相应的制冷系数；并通过数值计算分析了循环参数对循环的制冷率、制冷系数的影响。     

Performance analysis of a closed regenerated Brayton heat pump with internal irreversibilities

This paper analyses the performance of a real heat pump plant via methods of entropy generation minimization or finite‐time thermodynamics. The analytical relations between heating load and pressure ratio, and between coefficient of performance (COP) and pressure ratio of real closed regenerated Brayton heat pump cycles coupled to constant‐ and variable‐temperature heat reservoirs are derived. In the analysis, the irreversibilities include heat transfer‐irreversible losses in the hot‐ and cold‐side heat exchangers and the regenerator, the non‐isentropic expansion and compression losses in the compressor and expander, and the pressure drop loss in the pipe and system. The optimal performance characteristics of the cycle may be obtained by optimizing the distribution of heat conductances or heat transfer surface areas among the two heat exchangers and the regenerator, and the matching between working fluid and the heat reservoirs. The influence of the effectiveness of regenerator, the effectiveness of hot‐ and cold‐side heat exchangers, the efficiencies of the expander and compressor, the pressure recovery coefficient and the temperature of the heat reservoirs on the heating load and COP of the cycle are illustrated by numerical examples. Published in 1999 by John Wiley & Sons, Ltd.     

考虑热漏影响的热泵装置有限时间热力学性能

本文研究热漏对热泵装置最优性能的影响,导出存在热阻和热漏损失的定常态流不可逆卡诺热泵最佳供热系数与供热率关系,所得结果与仅存在热阻损失时的内可逆卡诺热泵供热系数供热率特性关系有量和质的区别。     

Irreversible four-temperature-level absorption refrigerator

A refrigeration cycle is modeled as a demonstration of an irreversible absorption refrigeration cycle. This four-temperature-level model takes into account the heat resistance, heat leakage, and irreversibilities due to internal dissipation of the working fluid. The fundamental optimal relationships between: (1) the coefficient of performance (COP) and the cooling load; (2) the maximum COP and the corresponding cooling load; and (3) the maximum cooling load and the corresponding COP of the cycle, all coupled to constant-temperature heat reservoirs, are derived by using finite-time thermodynamics. The optimal distribution relationships of the heat-transfer surface areas are also presented. Moreover, the effects of the cycle parameters on the COP and the cooling load of the cycle are studied by detailed numerical examples. The results obtained herein are useful for optimal design and performance improvement of absorption refrigeration cycles.