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1.
不可逆制冷机的最优性能   总被引:1,自引:0,他引:1  
陈林根  孙丰瑞 《制冷》1996,(1):28-31
在内可逆制冷机模型的基础上,用一常数项表示热源间的热漏,用一常系数项表示循环中除热阻和热漏外的其余所有不可逆性,建立了一类不可逆制冷机模型,并导出了其制冷率、制冷系数最佳关系和最大制冷系数。  相似文献   

2.
采用有限时间热力学研究了传热热阻,内部摩擦和冷头热漏三种不可逆损失对制冷机最优性能的影响。导出具有传热热阻,内部摩擦和冷头热漏不可逆损失的不可逆卡诺制冷机的最大制冷系数。  相似文献   

3.
建立一类存在热阻,热漏和内部耗散的定常流态联合制冷机循环模型,并研究其性能优化,导出制冷系数,制冷率基本优化关系和最大制冷系数及其相应的制冷率,给出了传热面积的最佳值工质最佳工作温度。所得结果适用于由任意个制冷机串接而成的联合制冷循环。  相似文献   

4.
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。  相似文献   

5.
伍文君  陈林根  孙丰瑞 《制冷》2005,24(2):5-10
以制冷率密度作为热力性能目标,综合考虑热漏、热阻和循环内不可逆性,对不可逆简单空气制冷机进行分析,导出了制冷率密度和制冷系数解析关系式,对制冷率密度进行了优化,并由数值计算分析了热漏、压比、热导率分配等参数对制冷率密度的影响特点.  相似文献   

6.
基于一类较为普遍的导热规律qχΔ(Tn),研究热阻和热漏对制冷机最优性能的影响,导出定常态流不可逆卡诺制冷机的最佳制冷率、制冷系数关系.所得结果包含了牛顿定律(n=-1)和线性唯象定律(n=-1)等条件下的特性关系,且与仅存在热阻损失时的内可逆卡诺制冷机制冷率制冷系数特性有量和质的区别.  相似文献   

7.
陶桂生  陈林根  孙丰瑞 《制冷》2008,27(1):10-16
用有限时间热力学理论和方法分析了热漏、热阻和其它不可逆性对定常流普适制冷循环模型性能的影响,导出了由两个绝热过程、两个等热容吸热过程和两个等热容放热过程组成的不可逆制冷循环的制冷率、制冷系数、炯损失率、炯输出率和生态学性能,并由数值计算分析了循环过程对循环性能的影响特点。所得结是包含了存在热阻、热漏和内不可逆损失的Diesel、Otto、Brayton、Atkinson、Dual、Miller和Camot制冷循环的特性。  相似文献   

8.
在热阻、摩擦和热漏影响下,研究卡诺制冷机传热面积的优化问题。推导出卡诺制冷机的最佳传热面积比以及最小传热面积与制冷系数和制冷率间的关系。  相似文献   

9.
陈林根  孙丰瑞 《制冷》1997,(1):22-25
研究热漏对联合制冷循环最优性能的影响,导出存在热阻和热源间热漏损失时由两个定常态流卡诺制冷机构成的联合制冷循环的最佳制冷率、制冷系数关系,并得到最大制冷系数及其相应的制冷率。给出了数值算例  相似文献   

10.
郑兆平  陈林根  孙丰瑞 《制冷》2007,26(4):10-15
本文研究了牛顿定律系统广义不可逆卡诺制冷机的有限时间[火用]经济性能,导出了存在热阻、热漏和其它内不可逆性时卡诺制冷机的最优利润率解析式以及相应的制冷系数界限,并用数值算例分析了热漏等因素对利润率和[火用]经济性能界限的影响。  相似文献   

11.
低温制冷机的性能评价   总被引:3,自引:0,他引:3  
作为对制冷系数COP概念的补充,建议采用yong效率(Exergy Efficien-cy)的概念来综合评价多级低温制冷机的性能,同时也为其性能优化过程提供理论指导。本文还以yong效率为基础,综合评价了4.2K和80K温区低温制冷机的发展水平,具有一定参考价值。  相似文献   

12.
The present study develops a theoretical model for the optimization of an irreversible Carnot refrigerator subject to a constraint of finite mass flow rate, which includes internal as well as external irreversibilities. By introducing two dimensionless parameters as indicative of the mass flow rates for the refrigerator, the new model allows detailed analyses on the finite mass flow rate allocation problem of working fluids among the hot- and cold-side heat exchangers of Carnot refrigerators. The analytical solutions of the maximum coefficient of performance (COP) for irreversible Carnot refrigerators are obtained under the equivalent of the finite-flow rate constraint. Furthermore, the influences of major parameters on the maximum COP and the corresponding mass flow rate allocation are examined and shown by numerical examples. The obtained results may provide a theoretical guidance for the optimal design and operation of real refrigerators.  相似文献   

13.
广义不可逆卡诺热泵的有限时间(火用)经济性能优化   总被引:1,自引:0,他引:1  
本文研究了牛顿定律系统广义不可逆卡诺热泵的有限时间炯经济性能,导出了存在热阻、热漏和其它内不可逆性时卡诺热泵的最优利润率解析式以及相应的供热系数界限,并用数值算例分析了热漏等因素对利润率和炯经济性能界限的影响。  相似文献   

14.
Finite-time thermodynamics optimization analysis based on the coefficient of performance and the ecological coefficient of performance criteria has been carried out. This was done analytically and numerically for a double-effect parallel flow absorption refrigerator with losses of heat resistance, heat leakage and internal irreversibility. The maximum of the coefficient of performance and the corresponding optimal conditions have been derived analytically. The optimum performance parameters, which maximize the coefficient of performance objective function have been investigated. The effects of irreversibility parameters on the general and optimal performances on the basis of COP and ECOP functions have been discussed. The results obtained may provide the basis for designing real double-effect parallel flow absorption refrigerators.  相似文献   

15.
A model of thermoelectric generator-driven thermoelectric refrigerator with external heat transfer is proposed. The performance of the combined thermoelectric refrigerator device obeying Newton’s heat transfer law is analyzed using the combination of finite time thermodynamics and non-equilibrium thermodynamics. Two analytical formulae for cooling load vs. working electrical current, and the coefficient of performance (COP) vs. working electrical current, are derived. For a fixed total heat transfer surface area of four heat exchangers, the allocations of the heat transfer surface area among the four heat exchangers are optimized for maximizing the cooling load and the coefficient of performance (COP) of the combined thermoelectric refrigerator device. For a fixed total number of thermoelectric elements, the ratio of number of thermoelectric elements of the generator to the total number of thermoelectric elements is also optimized for maximizing both the cooling load and the COP of the combined thermoelectric refrigerator device. The influences of thermoelectric element allocation and heat transfer area allocation are analyzed by detailed numerical examples. Optimum working electrical current for maximum cooling load and COP at different total number of thermoelectric elements and different total heat transfer area are obtained, respectively.  相似文献   

16.
用有限时间热力学方法分析工作在恒温热源TH、TL之间内可逆普适制冷机循环模型的炯经济性能,导出循环利润率与工质温比、制冷系数与工质温比的关系式,和利润率与制冷系数的特性关系。所得结果包含了内可逆Carnot、Diesel、Otto、Atkinson和Brayton制冷循环的有限时间炯经济性能。  相似文献   

17.
杨卓  罗二仓  陈燕燕 《制冷学报》2012,33(5):20-25+31
对一种新型热声制冷系统—双作用行波热声制冷机进行了研究,设计了一台在气液双作用行波热声发动机上使用的行波制冷机,并通过数值模拟优化了制冷机的结构尺寸。在环境温度300K,制冷温度250K的条件下,新型的双作用制冷机的COP达到了2.74,相对卡诺效率接近60%,声功消耗为534W,制冷量为1464.9W。通过对传统的斯特林制冷机及不同结构的行波制冷机计算比较。结果表明:从压比、效率、制冷量等多角度考察,新型的双作用行波制冷机更适合与气液双作用行波热声发动机耦合工作。它具有潜在的高效率、热驱动及无运动部件的优点,非常有潜力成为常规制冷方式的一种替代技术。  相似文献   

18.
The Carnot COP, which assumes a thermodynamically ideal cycle in which no irreversibilities exist, is often considered to be a design goal for actual cycles. However, the Carnot COP does not consider heat transfer mechanisms. Heat transfer at a finite rate is necessarily an irreversible process and unavoidable in a refrigeration cycle. The lack of consideration of rate processes reduces the usefulness of the Carnot COP as a realistic design goal. In this paper, the limitations of both thermodynamics and heat transfer are considered to identify a more realistic design goal for the COP of refrigeration cycles. The consideration of heat transfer limitations leads to a design rule for the optimum distribution of heat exchange area between the low- and high-temperature heat exchangers.  相似文献   

19.
磁布雷顿制冷机优化循环性能及参数设计   总被引:1,自引:0,他引:1  
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。  相似文献   

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