量子简并性对气体斯特林制冷循环性能的影响

基于理想量子气体的状态方程，分析了量子气体斯特林制冷循环中的回热特征，推导出循环的制冷系数一般表达式.获得了在强简并和弱简并条件下循环的制冷系数，对全面理解气体斯特林制冷机的性能有所帮助. 关键词： 量子简并性 斯特林制冷循环     

以理想玻色气体为工质的量子Ericsson制冷循环

文中基于理想玻色气体的状态方程 ,分析了以理想玻色气体为工质的量子 Ericsson制冷循环中的回热特征 ,推导出其制冷循环的制冷系数表达式。并在高温和低温条件下对制冷系数进行了讨论。这将对低温气体制冷机的研究提供理论依据。     

以理想费米气体为工质的量子制冷循环

本文基于理想费米气体的状态方程，分析了以理想费米气体为工质的量子Ericsson制冷循环中的回热特征，推导出其制冷循环的制冷系数表达式。并在高温和低温条件下对制冷系数进行了讨论。这将对低温制冷机的研究提供理论依据。     

不可逆费米奥托制冷循环性能分析

基于回热式不可逆奥托制冷循环和理想费米气体的状态方程,导出以费米气体为工质的奥托制冷循环的输入功、制冷量、制冷系数等重要性能参数的表达式,以此讨论费米气体的量子简并性、回热及内不可逆性对循环性能的影响,给出以理想费米气体为工质的回热式不可逆奥托制冷循环的性能特征。所得结果有助于进一步了解经典气体奥托制冷循环与量子气体奥托制冷循环的区别和联系。     

玻色气体的量子简并性对不可逆布雷顿制冷循环性能的影响

基于不可逆布雷顿制冷循环模型和理想玻色气体的状态方程,导出以玻色气体为工质的布雷顿制冷循环的输入功、制冷系数、制冷量等重要参数的表示式,由此讨论玻色气体的量子简并性和不可逆绝热过程对循环性能的影响,揭示以玻色气体为工质的不可逆布雷顿制冷循环的一般性能特性,从而导出一些重要结论．进而给出几种特殊情况下循环的性能特性．得到的结果有助于进一步了解经典布雷顿制冷循环和量子布雷顿制冷循环之间的区别和联系．     

不可逆量子自旋布雷顿制冷机最优性能

本文建立了以无相互作用1/2自旋系统为工质的不可逆量子布雷顿制冷循环模型,循环由两个等磁场过程和两个不可逆绝热过程组成。模型考虑了热阻、内摩擦、旁通热漏三种不可逆损失。应用有限时间热力学理论、量子主方程和量子半群方法,本文导出了该制冷机的循环周期、制冷率和制冷系数。应用数值计算和图例,给出了量子布雷顿制冷机的制冷率和制冷系数最优性能,并分析了量子摩擦和旁通热漏对其最优性能的影响。     

可逆简单空气制冷循环品质因子优化

本文利用经典热力学理论，以可逆简单空气制冷循环为研究对象，借用有限时间热力学提出的品质因子作为优化目标，通过理论分析和数值计算，推导出了品质因子与影响参数间的解析式.通过优化压比给出了制冷循环的最优性能，分析了循环温比对制冷循环最优性能的影响.结果表明，选用品质因子作为优化目标进行性能优化，存在最佳压比使得品质因子取得最大值，而且优化结果保证了制冷率和制冷系数之间的协调，是一种较优的折衷方案.     

不可逆自旋量子制冷循环参数的优化设计

基于量子主方程和半群逼近方法，研究以许多无相互作用的自旋-1/2系统为工质的、由两个绝热和两个等磁场过程组成的不可逆量子制冷循环的一般性能特性。导出循环的性能系数、制冷率和输入功率等重要性能参数的表达式。应用数值求解，对受有限循环时间约束的制冷率进行了优化，计算了最大制冷率和相应的最佳性能参数，确定了性能系数的最佳区域和工质温度及两个等磁场过程时间的优化范围。进而详细分析了高温下循环的优化性能，所得结果被进一步推广，以致可直接用来描述由自旋-J系统为工质的量子制冷循环的性能。     

以一维谐振子势阱中的单粒子为工质的量子热机性能分析

建立了以一维谐振子势阱中的单粒子为工质的量子热机模型.当势阱壁宽度和粒子的量子态缓慢改变时, 该热机类似于经典卡诺热机对外做功.假设势阱壁移动速度非常缓慢并且考虑热漏, 推导出量子热机循环的输出功率和效率等重要性能参数的一般表达式.通过优化分析, 获得了热机循环中各主要性能参数的最佳优化值和优化区间.     

量子斯特林制冷机的回热特性

基于理想玻色气体的状态方程 ,分析以理想玻色气体为工质的量子斯特林制冷机具有非理想回热特性 ,导出循环的制冷系数和制冷量的表达式 ,并对结论进行一些有意义的讨论 ,所得结果将对低温气体制冷机的研究提供一些理论依据     

The performance evaluation of a micro/nano-scaled cooler working with an ideal Bose gas

Based on the size effect of a confined ideal Bose gas, the design concept of a quantum cooler is originally put forward. The cooler consists of two long tubes with the same length but different sizes of cross section, which are filled up with the ideal Bose gas, and is operated between two heat reservoirs. Expressions for the refrigeration rate and coefficient of performance (COP) of the cooler are derived. The effects of the size effect on the refrigeration rate and COP are discussed. The general performance characteristics of the cooler are revealed.     

Performance of an irreversible quantum refrigeration cycle

A new model of a quantum refrigeration cycle composed of two adiabatic and two isomagnetic field processes is established. The working substance in the cycle consists of many non-interacting spin-1/2 systems. The performance of the cycle is investigated, based on the quantum master equation and semi-group approach. The general expressions of several important performance parameters, such as the coefficient of performance, cooling rate, and power input, are given. It is found that the coefficient of performance of this cycle is in the closest analogy to that of the classical Carnot cycle. Furthermore, at high temperatures the optimal relations of the cooling rate and the maximum cooling rate are analysed in detail. Some performance characteristic curves of the cycle are plotted, such as the cooling rate versus the maximum ratio between high and low ``temperatures' of the working substances, the maximum cooling rate versus the ratio between high and low ``magnetic fields' and the ``temperature' ratio between high and low reservoirs. The obtained results are further generalized and discussed, so that they may be directly applied to describing the performance of the quantum refrigerator using spin-$J$ systems as the working substance. Finally, the optimum characteristics of the quantum Carnot and Ericsson refrigeration cycles are derived by analogy.     

Performance characteristic of a Stirling refrigeration cycle in micro/nano scale

The aim of the paper is to present the performance characteristics of a Stirling refrigeration cycle in micro/nano scale, in which the working substance of cycle is an ideal Maxwellian gas. Due to the quantum boundary effect on the gas particles confined in the finite domain, the cycle no longer possesses the condition of perfect regeneration. The inherent regenerative losses, the refrigeration heat and coefficient of performance (COP) of the cycle are derived. It is found that, for the micro/nano scaled Stirling refrigeration cycle devices, the refrigeration heat and COP of cycle all depend on the surface area of the system (boundary of cycle) besides the temperature of the heat reservoirs, the volume of system and other parameters, while for the macro scaled refrigeration cycle devices, the refrigeration heat and COP of cycle are independent of the surface area of the system. Variations of the refrigeration heat ratio r_R and the COP ratio r_ε with the temperature ratio τ and volume ratio r_V for the different surface area ratio r_A are examined, which reveals the influence of the boundary of cycle on the performance of a micro/nano scaled Stirling refrigeration cycle. The results are useful for designing of a micro/nano scaled Stirling cycle device and may conduce to confirming experimentally the quantum boundary effect in the micro/nano scaled devices.     

The performance characteristics of an irreversible quantum Otto harmonic refrigeration cycle

In this paper, an irreversible quantum Otto refrigeration cycle working with harmonic systems is established. Base on Heisenberg quantum master equation, the equations of motion for the set of harmonic systems thermodynamic observables are derived. The simulated diagrams of the quantum Otto refrigeration cycle are plotted. The relationship between average power of friction, cooling rate, power input, and the time of adiabatic process is analyzed by using numerical calculation. Moreover, the influence of the heat conductance and the time of iso-frequency process on the performance of the cycle is discussed.