An integral identification method of characteristic parameters and optimization of parallel connection heat transfer systems based on the power flow method. (October 2018)

• Record Type: Journal Article
• Authors: Zhang, Meng-Qi; Chen, Qun; Shao, Wei; Chen, Xi; Hao, Jun-Hong
• Is Part Of: Applied thermal engineering. Volume 143(2018)
• Page Start: 1057
• Page End: 1067
• Publication Date: 2018-10
• Subjects: Heat transfer system -- Integral identification and optimization -- Power flow method -- Characteristic parameters -- Thermal resistance; Heat engineering -- Periodicals; Heating -- Equipment and supplies -- Periodicals; Periodicals; 621.40205
• DOI: 10.1016/j.applthermaleng.2018.08.016
• Languages: English
• ISSNs: 1359-4311

Abstract

Highlights: Integral identification of heat transfer and fluid flow characteristic parameters. Proposed method can flexibly select proper parameters to measure in identification. Combining power flow and fluid flow models offer an integral optimization model. Results show the limitation of fixed node-temperature method and balanced flow criterion. Abstract: Optimization of heat transfer systems benefits energy conservation, but the conventional fixed node-temperature operation strategy hardly offers the optimal performance under changing working conditions. This paper utilizes the power flow method to construct the integral heat transfer model and combines the overall flow resistance model to set up the integral constraints of heat transfer systems with independent variables. On this basis, we develop an integral identification method to identify the free degree of systems and the characteristic parameters of each component, and propose the corresponding optimization method, which is universal and has been applied to many kinds of heat transfer systems. For the convenience and economy of experiment, a parallel-connected counter-flow heat exchanger network is studied to validate the identification method and the optimization method. The experimental results show that the identified characteristic parameters by the newly proposed method have enough accuracy for practical use; while the optimization method offers the optimal operating parameters with the least power consumption under given conditions. When the operating frequency of the pump in a cold-water loop deviates the optimal one of 10%, the total pumping power consumption of the system increases up to 18.2%. Meanwhile, a bigger deviation will lead to a larger pumping power consumption. Besides, the node temperatures in the optimal cases vary with the heat loads, which illustrates the limitation of fixed node-temperature operation strategy.