【正文】 ving effect is remarkable. This paper also for a library design the central air conditioning control system, and discusses the central airconditioning energy saving principles: environmental temperature through the thermostat, and feedback to the inverter frequency changes to adjust by the frequency, the rotation fans and pumps with motor speed changes that the fans and pumps air, flow change, thus to achieve the purpose of saving energy. Keywords: Central airconditioner； Energysaving system； Transducer； PLC 目錄 III 目錄 摘 要 .............................................................................................................................I Abstract....................................................................................................................... II 1 緒論 .......................................................................................................................... 1 ............................................................................................................ 1 ......................................................................................................... 2 ........................................................................................... 2 ...................................................................... 2 2 中央空調系統(tǒng)節(jié)能可行性分析 ................................................................................ 3 ......................................................................... 3 制冷主機： .............................................................................................. 3 冷凍水泵 ： .............................................................................................. 3 冷卻水泵 ： .............................................................................................. 4 冷卻塔： ................................................................................................. 4 風機盤管 ： .............................................................................................. 4 ........................................................................................... 4 ................................................................................ 6 2． 4 本課題的主要研究內容 ................................................................................... 7 節(jié)能的可行性分析 .............................................................................................. 8 3 中央空調系統(tǒng)主控制器 ............................................................................................ 8 PLC的發(fā)展 ......................................................................................................... 9 PLC的特點 ....................................................................................................... 10 (1) 編程方法簡單易學，指令豐富 ................................................................... 10 (2) 功能強，性能價格比高 .............................................................................. 10 (3) 硬件配套齊全，用戶使用方便，適應性強 .................................................. 10 (4) 無觸點面配線，可靠性高，抗干擾能力強 .................................................. 10 (5)系統(tǒng)的設計、安裝、調試工作量少 .............................................................. 10 (6)維修工作量小，維修方便 ............................................................................ 10 (7)體積小，功耗低 .......................................................................................... 11 PLC的應用領域 ................................................................................................ 11 (1) 開關量邏輯控制 ........................................................................................ 11 (2) 運動控制 ................................................................................................... 11 (3) 閉環(huán)過程控制 ............................................................................................ 11 (4) 數(shù)據(jù)處理 ................................................................................................... 11 (5) 通訊聯(lián)網(wǎng) ................................................................................................... 11 PLC的組成 ....................................................................................................... 12 4 基于 PLC 控制的中央空調系統(tǒng) ............................................................................... 13 .......................................................................................................... 13 .................................................................................. 13 ................................................................................................ 15 ................................................................................................ 15 ................................................................................................ 15 （ 1）最大限度地滿足被控對象的控制要求 ................................................... 15 目錄 IV （ 2）保證 PLC控制系統(tǒng)安全可靠 ................................................................. 16 （ 3）力求簡單、經(jīng)濟、使用及維修方便 ....................................................... 16 （ 4）適應發(fā)展的需要 ................................................................................... 16 5 某圖書館中央空調變頻節(jié)能系統(tǒng)設計 ................................................................ 17 概述 ............................................................................................................... 17 負荷計算 ........................................................................................................ 17 中央空調控制系統(tǒng)設計 ................................................................................... 19 6 中央空調控制系統(tǒng)硬件設計 .................................................................................. 21 硬件電路設 計 ................................................................................................. 21 PLC選型 .............................................................................................. 21