共查询到19条相似文献,搜索用时 218 毫秒
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基于能量分析的观点,建立了反映四热源吸收式热变换器泵热率与熵产率之间最佳折衷的生态学准则。导出了线性(牛顿)传热定律下生态学目标与泵热系数的优化关系、最大生态学目标值及其相对应的泵热系数、泵热率和熵产率以及最大泵热率时的生态学目标和熵产率。通过数值算例分析得到了吸收式热变换器的生态学优化准则。计算发现,与最大泵热率目标相比,最大生态学目标牺牲了27.3%的泵热率。使循环熵产率降低了77.0%。泵热系数增加了55.4%,表明生态学准则对吸收式热变换器优化设计是一种具有长期效应的可选优化目标。 相似文献
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Based on an endoreversible four-heat-reservoir absorption-refrigeration-cycle model, the optimal thermo-economic performance of an absorption-refrigerator is analyzed and optimized assuming a linear (Newtonian) heat-transfer law applies. The optimal relation between the thermo-economic criterion and the coefficient of performance (COP), the maximum thermo-economic criterion, and the COP and specific cooling load for the maximum thermo-economic criterion of the cycle are derived using finite-time thermodynamics. Moreover, the effects of the cycle parameters on the thermo-economic performance of the cycle are studied by numerical examples. 相似文献
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The thermo-economic objective function of a heat transformer may include other objective functions such as the coefficient of performance and specific heat pumping load. It is defined as the heat-pumping load divided by the total cost per unit time and its expression is derived from the general cycle model of an irreversible heat-transformer. The general objective function is used to analyze the thermoeconomic and thermodynamic optimum performance of a heat transformer affected by multi-irreversibilities. The bounds of some important parameters are determined. The problem of how to choose optimally these parameters are discussed. The results obtained here can provide some new theoretical guidance for the optimal design and operation of heat transformers and heat engines. 相似文献
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Optimum thermoeconomic and thermodynamic performance characteristics of an irreversible three-heat-source heat pump 总被引:1,自引:0,他引:1
The coefficient of performance and specific heating load of an irreversible three-heat-source heat pump are given by using a general cycle model affected by the finite-rate heat transfer, heat leak and internal irreversibility of the cyclic working fluid. The heat pumping load divided by the total cost per unit time is taken as a new objective function and used to investigate the performance of the heat pump. The thermoeconomic and thermodynamic performance characteristics of the heat pump are discussed in detail. Some important performance parameters such as the thermoeconomic objective function and coefficient of performance are optimized. The optimally operating regions of the heat pump and the bounds of several performance parameters are determined. Finally, it is pointed out that the Carnot heat pump may be taken as a special case of a three-heat-source heat pump and consequently its optimal performance can be directly derived from the results obtained here. 相似文献
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The performance optimization of an endoreversible air refrigerator with variable‐temperature heat reservoirs is carried out by taking the cooling load density, i.e. the ratio of cooling load density to the maximum specific volume in the cycle, as the optimization objective in this paper. The analytical relations of cooling load, cooling load density and coefficient of performance are derived with the heat resistance losses in the hot‐ and cold‐side heat exchangers. The maximum cooling load density optimization is performed by searching the optimum pressure ratio of the compressor, the optimum distribution of heat conductance of the hot‐ and cold‐side heat exchangers for the fixed total heat exchanger inventory, and the heat capacity rate matching between the working fluid and the heat reservoirs. The influences of some design parameters, including the heat capacitance rate of the working fluid, the inlet temperature ratio of heat reservoirs and the total heat exchanger inventory on the maximum cooling load density, the optimum heat conductance distribution, the optimum pressure ratio and the heat capacity rate matching between the working fluid and the heat reservoirs are provided by numerical examples. The refrigeration plant design with optimization leads to a smaller size including the compressor, expander and the hot‐ and cold‐side heat exchangers. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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Irreversible four-temperature-level absorption refrigerator 总被引:2,自引:0,他引:2
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. 相似文献
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Performance optimization of an irreversible four-heat-reservoir absorption refrigerator 总被引:2,自引:0,他引:2
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. 相似文献
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Performance analysis of two stage combined heat pump system based on thermoeconomic optimization criterion 总被引:4,自引:0,他引:4
A thermoeconomic performance analysis based on a new kind of optimization criterion has been performed for a two stage endoreversible combined heat pump cycle model. The optimal performances and design parameters that maximize the objective function (heating load per unit total cost) are investigated. The optimal temperatures of the working fluids, the optimum performance coefficient, the optimum specific heating load and the optimal distribution of the heat exchanger areas are determined in terms of technical and economical parameters. The effects of the economical parameter on the global and optimal performances have been discussed. 相似文献
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Tong Zheng Lingen Chen Fengrui Sun Chih Wu 《International Journal of Thermal Sciences》2004,43(12):4343-1195
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. 相似文献