壓縮式冷凍系統之最適化設計

Abstract

本研究針對壓縮式冷凍系統，提出以數學規劃法進行其最適化的設計。首先提出一個可以描述所有壓縮式冷凍系統需求狀況的系統超結構，再透過對於超結構中每個部份之實際物理意義來建立限制方程式，將壓縮式冷凍系統之最適化設計問題，轉變成為一個混合整數非線性規劃(MINLP)的數學問題，再根據不同的目標函數，經求解後即可獲得最適化設計結果，其中包含冷凍系統整體的架構和系統中各階的操作條件。 文中提出三個例子，用以驗證本研究所提出之系統超結構及其數學模型可以設計出最適化之壓縮式冷凍系統架構與其操作條件。三個例子中，先是以最少壓縮機作功量為目標函數，限制壓縮式冷凍系統為單環的情況下，比較壓縮式冷凍系統結構與冷媒種類對壓縮機作功量的影響，並探討其原因。接著則是以最低年總成本為目標函數，在固定冷凍系統結構之下，分別成功處理單一熱負載和多重熱負載的情況之下的壓縮式冷凍系統設計問題。

This research aims to develop a mathematical model for handling the design problem of a compression refrigeration system. A superstructure is firstly proposed which can be used to describe all possible configurations of a compression refrigeration system. By describing relevant constrains for each part of the superstructure, and adapting total compressor work or total annual cost as the objective function, the problem of designing the compression refrigeration system can be formulated as a mixed-integer nonlinear program (MINLP) that can then be solved ot determine the optimal configurations and operating conditions. Three numerical examples are presented, with simple or multiple refrigeration loads, in this work in order to demonstrate that the proposed superstructure-based MINLP formulation can be used to decide the suitable configuration of a compression refrigeration system.