應用數學規劃法設計冰水網路及冰水主機操作策略

Abstract

本文同時針對冰水網路系統及冰水主機操作策略，提出以數學規劃法的方式進行整體最適化的設計。 首先我們提出一個可以描述所有可能的冰水網路超結構 ，針對超結構中的每一個單元逐步建立規範方程式，即可將冰水網路系統的最適化問題變成一個典型的混合整數非線性規劃(MINLP)數學問題， 再經求解可以獲得冰水網路系統的最適化設計。 目標函數(1)為最小總冰水消耗量，對一個虛擬的例子作不同情境的最適化並比較其結果；接著，基於目標函數(1)的結果，我們為了得到唯一解，所以提出目標函數(2) 為每一冰水使用單元最小通過量。

再者，我們也提出冰水主機之超結構，考慮不同的冰水主機操作上下限，利用目標函數(3)為最少固定及變動操作成本去探討不同網路結構對其操作策略之影響 。接著透過目標函數(4)使得冰水操作方式可以獲得一個唯一解。 最後我們利用一個簡單的冰水網路合成例子， 驗證本研究所提出之數學模型及超結構上可設計出適當的冰水網路設計 與冰水主機操作策略織架構與操作條件。

This work aims to develop a mathematical model for the synthesis of refrigerated water network systems and chiller operating strategy simultaneously. First of all, we proposed one model which includes all possible configurations of refrigerated water network system under all conditions. By setting relevant constraints up for each part of the superstructure, the design problem of refrigerated water network system is formulated as a mixed-integer nonlinear program that can be solved for optimal configuration of refrigerated water network. Objective functions 1 and 2 are considered which involving the mimnimization of refrigerated water supply and obtaining a unique network structure. Furthermore we also proposed a superstructure for chillers' operation, considering different operating upper and lower bounds. In this work, two objective functions are considered to minimize fixed and variable operating cost. Finally, numerical examples are used to show that the proposed approach can provide the optimal design of refrigerated water network system and chiller operating strategy.