Operation optimization of variable frequency pumps in compound series‐parallel heat transfer systems based on the power flow method

Abstract

The optimal match of multiple operation parameters in heat transfer systems (HTSs) is the key to trade‐off heat transfer and flow resistance for energy conservation. For a compound series‐parallel HTS, this study applies the power flow model and the driving‐resistance model to build the heat transfer and fluid flow constraints of the whole system directly, instead of individual components. Utilizing these constraints together with the Lagrange multiplier method offers the optimal operating frequencies of each variable frequency pumps (VFP) with the minimum pumping power consumptions under different heat loads. Operating the experiment platform with the optimized parameters shows that the heat load increment in parallel branches only needs to increase the operating frequency of VFP in the related hot‐water loop, whereas the heat load increment in series branches needs to increases the operating frequencies of VSPs in both cold‐water and the corresponding hot‐water loops. When the heat load varies from 10 to 11 kW in the parallel branch, the downstream, and the upstream of the series branch, the total pumping power consumptions of all VFPs increase by 19.45%, 43.86%, and 39.99%, respectively. It means assigning the additional heat load in the parallel branch is more energy efficient.

Heat current method for integrated analysis and optimization of thermodynamic systems

“…由于热量流方法中不对物理过程进行额外的 数学简化, 其分析与计算结果更为准确. 目前, 热量流 法已被应用于多种热力系统的模拟与优化研究中, 如 换热系统 [24] 、蒸汽发电循环 [25] 、有机朗肯循环 [26] 、 吸收式储能系统 [27,28] 与制冷系统 [29] 、超临界CO 2 换 热 [30] 与发电循环 [31] 、水泥回转窑余热回收系统 [32] 和 移动填充床 [33] 等. 由于热系统热量流模型具有电路图 的形式, 热量流法也被应用于电-热综合能源系统的分 析与优化中 [34,35] .…”

An Integrated Three-Level Synergetic and Reliable Optimization Method Considering Heat Transfer Process, Component, and System

“…where H i is the total head, H s,i is the static head, H d,i is the dynamic head of the pipeline network, and H e,i is the head from pressure drops in heat exchangers. Static heads H s,i are controlled by the structure of the pipeline network and can be treated as constants, while the dynamic head H d,i is [19]:…”

“…An effective solution for this problem is the heat current method developed by the authors' group [14], which uses the concept of a re-defined thermal resistance of heat exchangers and reveals the global heat transfer law in HTS. Moreover, combining the heat current model and circuitous philosophy directly gives the governing equations of HTSs without unnecessary intermediate parameters, and hence the optimization can be simplified effectively [15][16][17][18][19].…”

Research on the steady‐state operation optimization technology of oil pipeline

“…At present, computer technology has been applied in many fields to obtain optimal solutions, such as microgrid, solar energy, and renewable energy. [24][25][26][27][28][29][30][31][32] Many scholars have also proposed T A B L E 1 Improvement of process equipment or technology of the oil pipeline system Frequency control technology The output power of the motor is effectively matched with the pipe flow, which reduces energy consumption…”

“…With the continuous development of mathematics and computer science, the continuous updating of artificial intelligence technology and intelligent optimization algorithms makes the process of solving many engineering problems simple, and the solution is better. At present, computer technology has been applied in many fields to obtain optimal solutions, such as microgrid, solar energy, and renewable energy 24‐32 . Many scholars have also proposed different solutions in the hot oil pipeline system, as shown in Table 2.…”