An entransy dissipation resistance-based method for optimization of heat exchanger networks

doi:10.11949/j.issn.0438-1157.20150281

Abstract

Abstract:

Based on the concept of entransy dissipation resistance, this paper analyzes all the heat transfer processes in heat exchanger networks, the characteristics of variable speed pumps (VSPs) and the characteristics of pipeline resistances, to propose a general relationship, which connects the geometrical structures of each heat exchanger and the operating parameters of VSPs directly to the demands of users and the supply of refrigerating unit. To illustrate the applications of the newly proposed optimization method, a simple central variable water volume (VWV) chiller system is taken as an example. Results show that the optimal operating parameters with the lowest energy consumption can be obtained by the entransy dissipation resistance-based method. In variable operating cases, the enlargement of the heat transfer rates bring the increasing of the operating speeds of each VSP with different degrees, which are related with the characteristics of the working fluids and the pipeline resistances.

Key words: heat exchanger network, optimization, entransy dissipation resistance, variable water volume system, operating parameter

摘要：

基于(火积)耗散热阻的概念, 分析了换热器网络中的传热过程, 并结合变频泵的性能分析和管网的阻力分析, 建立了换热器网络中结构参数、运行参数和用户需求之间的直接联系, 完善了换热器网络优化的数学模型。在此基础上, 构建了基于(火积)耗散热阻换热器网络优化的方法。最后以一个典型的有变频水系统的换热器网络为例, 阐释了基于(火积)耗散热阻的换热器网络优化方法。研究结果表明, 在给定换热器网络中各换热器热导的情况下, 通过优化计算可以获得使换热器网络中总泵能耗最小的运行参数。在变工况运行的情况下, 随着换热器网络换热量的增大, 各变频泵的运行参数出现不同程度的增大, 增大的速度与工质的性质和管网的阻力特性等因素有关。

关键词: 换热器网络, 优化, 火耗散热阻, 变频水系统, 运行参数

CLC Number:

TK172

WANG Yifei, CHEN Qun. An entransy dissipation resistance-based method for optimization of heat exchanger networks[J]. CIESC Journal, 2015, 66(S1): 272-276.

王怡飞, 陈群. 基于(火积)耗散热阻的换热器网络优化[J]. 化工学报, 2015, 66(S1): 272-276.

References 17

[1]	Papoulias S A, Grossmann I E. A structural optimization approach in process synthesis (2): Heat-recovery networks [J]. Comput. Chem. Eng., 1983, 7: 707-721.
[2]	Bjork K M, Nordman R. Solving large-scale retrofit heat exchanger network synthesis problems with mathematical optimization methods [J]. Chem. Eng. Process, 2005, 44: 869-876.
[3]	Yee T F, Grossmann I E, Kravanja Z. Simultaneous optimization models for heat integration (1): Area and energy targeting and modeling of multi-stream exchangers [J]. Comput. Chem. Eng., 1990, 14: 1151-1164.
[4]	Dolan W B, Cummings P T, Levan M D. Process optimization via simulated annealing — application to network design [J]. AIChE J., 1989, 35: 725-736.
[5]	Dolan W B, Cummings P T, Levan M D. Algorithmic efficiency of simulated annealing for heat-exchanger network design [J]. Comput. Chem. Eng., 1990, 14: 1039-1050.
[6]	Lewin D R, Wang H, Shalev O. A generalized method for HEN synthesis using stochastic optimization(I): General framework and MER optimal synthesis [J]. Comput. Chem. Eng., 1998, 22: 1503- 1513.
[7]	Lewin D R. A generalized method for HEN synthesis using stochastic optimization(II): The synthesis of cost-optimal networks [J]. Comput. Chem. Eng., 1998, 22: 1387-1405.
[8]	Fesanghary M, Mahdavi M, Minary-Jolandan M, Alizadeh Y. Hybridizing harmony search algorithm with sequential quadratic programming for engineering optimization problems [J]. Comput. Method Appl. M, 2008, 197: 3080-3091.
[9]	Lin B, Miller D C. Solving heat exchanger network synthesis problems with Tabu Search [J]. Comput. Chem. Eng., 2004, 28: 1451-1464.
[10]	Xu Y C, Chen Q. An entransy dissipation—based method for global optimization of district heating networks [J]. Energ. Buildings, 2012, 48: 50-60.
[11]	Chen Q, Xu Y C. An entransy dissipation—based optimization principle for building central chilled water systems [J]. Energy, 2012, 37: 571-579.
[12]	Chen Q. Entransy dissipation—based thermal resistance method for heat exchanger performance design and optimization [J]. Int. J. Heat Mass Tran., 2013, 60: 156-162.
[13]	Xu Y C, Chen Q. Minimization of mass for heat exchanger networks in spacecrafts based on the entransy dissipation theory [J]. Int. J. Heat Mass Tran., 2012, 55: 5148-5156.
[14]	Yang Z Y, Borsting H. Energy efficient control of a boosting system with multiple variable-speed pumps in parallel //IEEE Decis. Contr. P[C]. 2010: 2198-2203.
[15]	Yang Z Y, Borsting H. Optimal scheduling and control of a multi-pump boosting system//IEEE Intl. Conf. Contr. [C]. 2010: 2071-2076.
[16]	Rishel J B. HVAC Pump Handbook[M]. New York: McGraw-Hill, 1996.
[17]	White F M. Fluid Mechanics[M]. 4th ed. Boston, Mass.: WCB/McGraw-Hill, 1999.