热阻和回热损失对铁电斯特林制冷机的(火用)经济优化性能的影响

应用有限时间Yong分析法，研究热阻及回热损失对铁电斯特林制冷机Yong经济优化性能的影响。利用铁电晶体的热力学特性，考虑传热规律服从牛顿定律，得到铁电斯特林制冷机的基本优化关系。以利润率为目标，导得最大利润率情况时的制冷系数及其他性能参数，所得结论可为铁电斯特林制冷机的研制和设计提供指导。     

斯特林制冷机的最佳火用输出率

研究导热和回热损失对斯特林制冷机火用优化性能的影响，导出制冷机的最佳火用输出率与制冷系数以及与制冷率间的关系。由此揭示了斯特林制冷机火用优化性能的主要特征，并与制冷率优化性能作了比较，获得一些对实际制冷机有指导意义的新结论。     

对《斯特林制冷机的制冷系数与制冷率间的关系》一文的讨论

从斯特林制冷机与卡诺制冷机的主要区别,所设的斯特林制冷机的特性,以及有限时间热力学分析的方法等三个方面讨论了《斯特林制冷机的制冷系数与制冷率间的关系》一文中所存在的主要问题。它将有助于对有限时间热力学的正确认识和进一步了解。     

斯特林制冷机的制冷系数与制冷率间的关系

从热量交换和循环运行两个力面研究了时间对斯特林制冷机的影响;推导出制冷率与制冷系数之间的关系,并且分析了各种因素对这一关系的影响。还对斯特林制冷机进行了有限时间热力学分析,以求在理论与应用的结合方面前进一步。     

斯特林制冷机的最佳制冷系数和制冷率间的关系

讨论了考虑回热损失时斯特林制冷机最佳制冷系数与制冷率之间的关系。     

回热损失对磁斯特林制冷循环制冷率的影响

从铁磁质的磁化强度一般表示式出发，探讨热阻和回热损失对磁斯特林制冷循环性能的影响，导出最大制冷率及其它性能参数。得到了结果适用于以顺磁质为工质的磁斯特林制冷循环。并指出在理想回热条件下的结论也适用于磁卡诺制冷循环。     

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。     

经典极限下量子卡诺制冷机有限时间热力学性能界限和优化准则

研究了量子卡诺制冷机的最优性能和有限时间热力学优化准则，得到了量子制冷机制冷率与致冷系数之间的优化关系以及制冷的有限时间热力学性能界限。     

双级斯特林制冷机的模拟及优化设计

为了获得1.5 W@40 K的制冷性能,设计了一台双级斯特林制冷机。建立了双级斯特林制冷机的Sage一维整机模型,并进行数值模拟。在限制频率和排出器长度条件下,对双级斯特林制冷机的热力学和动力学参数进行了优化设计,优化后的双级斯特林制冷机在达到所要求的1.5 W@40 K的制冷性能时,其膨胀机效率为2.72%。     

斯特林制冷机的最佳Yong输出率

研究导 回热损失对斯特林制冷机Ｙｏｎｇ优化性能的影响，导出制同的最佳Ｙｏｎｇ输出率与制冷系数以及与制冷率间的关系。由此揭示了斯特林制冷机Ｙｏｎｇ优化性能的主要特征，并与制冷优化性能作了比较，获得一些对实际制冷机有指导意义的新结论。     

A model for exergy analysis and thermodynamic bounds of Stirling refrigerators

A thermodynamic model based on exergy flow through a Stirling Refrigerator is developed. Important irreversibilities of the refrigerator due to external heat transfer with the reservoirs, heat leak, flow and heat transfer in regenerator are included in the model. Expansion and compression efficiencies are introduced in the model to account for the losses in these processes. The effect of a control phase shift between the mass flow rate and pressure across regenerator on the performance of the refrigerator is presented. Analytical solutions representing important quantities in the design of Stirling refrigerators such as the load curve, cooling power and efficiency in terms of basic system input parameters are developed. Thermodynamic bounds for the performance of Stirling refrigerators are obtained. Results indicating a compromise between cooling power and efficiency that are dependent on the constraint of the system are presented and discussed.     

Design and performance of a room-temperature hybrid magnetic refrigerator combined with Stirling gas refrigeration effect

The experimental prototype described in this work is a hybrid refrigerator that combines the active magnetic refrigeration effect with the Stirling gas regenerative refrigeration effect. In this prototype, gadolinium sheets are packed in the regenerator matrix for both Stirling and active magnetic regenerative refrigeration. Experimental tests were carried out to measure the cooling performance of this hybrid prototype. The influence of the phase angle on the cooling performance was investigated, and a reasonable phase angle of 90° was determined to obtain optimal cooling performance. By combining the two refrigeration effects, a minimum cooling temperature without heat load of 3.5 °C was reached, which is lower than that of 6.5 °C for the pure Stirling refrigeration effect without the magnetic cooling effect. The results of this study show that the cooling performance is improved by 24% for the hybrid effects compared with that exploiting only the Stirling gas refrigeration effect.     

Cooling capacity of Stirling cryocoolers — the split cycle and nonideal gas effects

The general expression for the cooling capacity of a Stirling cooler operating with a nonideal gas is derived. The result demonstrates that thermodynamic regions of negative Joule-Thomson coefficient should be avoided. It is also shown that heat transfer to the expansion space occurs during three of the four steps of the ideal Stirling cycle.     

一类斯特林制冷机的生态学优化准则

研究存在热阻和回热损失的斯特林制冷机的生态学优化准则,得到一些新的性能参数,可为斯特要制冷机的优化设计和最佳工况的选择提供些新理论指导。     

Optimization of an air-filled Beta type Stirling refrigerator

The Stirling machine has many successful applications mainly thanks to its high efficiency, fast cool-down, small size, light weight, low power consumption and high reliability (heating and cooling). A Beta type Stirling refrigerator is studied experimentally and numerically. The mathematical model takes into account complex phenomena related to compressible fluid mechanics, thermodynamics and heat transfer losses. A special attention is paid to the effect of geometric parameters such as dead and swept volumes respectively in compression and expansion spaces. Regenerator length, diameter and porosity are also discussed and optimal parameters are proposed. The effect of speed on the cold end temperature and refrigerator's performances is also investigated. Net cooling capacity, input power and COP were estimated at different conditions. Results allow understanding the physical processes occurring in the refrigerator and for predicting its performance.     

Analyzing the thermodynamic performance of a hybrid system consisting of a gas turbine and two Stirling engines in series and parallel configurations

Clean Technologies and Environmental Policy - This paper aims to analyze the thermodynamic performance of a gas turbine–Stirling engine hybrid system with series and parallel configurations....     

Optimal performance of regenerative cryocoolers

The key component of a regenerative cryocooler is its regenerative heat exchanger. This device is subject to losses due to imperfect heat transfer between the regenerator material and the gas, as well as due to viscous dissipation. The relative magnitudes of these losses can be characterized by the ratio of the Stanton number St to the Fanning friction factor f. Using available data for the ratio St/f, results are developed for the optimal cooling rate and Carnot efficiency. The variations of pressure and temperature are taken to be sinusoidal in time, and to have small amplitudes. The results are applied to the case of the Stirling cryocooler, with flow being generated by pistons at both sides of the regenerator. The performance is found to be close to optimal at large ratio of the warm space volume to the regenerator void volume. The results are also applied to the Orifice Pulse Tube Refrigerator. In this case, optimal performance additionally requires a large ratio of the regenerator void volume to the cold space volume.     

Performances of the mixed-gases Joule-Thomson refrigeration cycles for cooling fixed-temperature heat loads

Numerous mixed-gases refrigeration cycle configurations based on Joule-Thomson effects were developed in the past several decades. In this paper, comprehensive thermodynamic analyses were made on two typical cycle configurations to learn their performance for cooling fixed-temperature heat loads. One is the single-stage cycle without phase separators; the other is the auto-cascade refrigeration cycle which has at least one phase separator. An exergy model was developed to analyze the thermodynamic performance of those refrigeration cycles. Comprehensive comparisons were made on the performance of the recuperative throttling cycles using multicomponent mixture as refrigerant, including extensive simulations and optimizations of mixtures and cycle configurations. The results show that the auto-cascade cycle can improve thermodynamic performance in the case of using mixtures with increased fraction of high-boiling components, however, degrade the performance when using mixtures with increased fraction of low-boiling components. The results also show that the mixed refrigerant is the most important designing parameter in the design of such mixed-gases refrigeration system. Different cycle configuration has different optimal mixture composition. When using optimal mixtures, both cycles (separation and non-separation) can provide approximately equal performance.