變頻器及直接數位控制器在空調系統中之節能應用

The applications and energy savings for variable frequency drives and direct digital controllers in HVAC systems

陳湘中(Shiang-Chung Chen)

指導教授 ： 蕭瑛東

淡江大學/工學院/電機工程學系碩士在職專班/碩士(2006年)

https://doi.org/10.6846/TKU.2006.00676

摘要

本論文主要研究變頻器及直接數位控制器在空調系統中之應用。變頻器係以三相交流60Hz，電壓範圍從380- 500 VAC，驅動馬達以鼠籠式三相感應馬達為基礎，搭配系統控制用的直接數位控制器，並以多組泵與風扇機組，實行系統運作。文中係以泵用直接數位控制器為例，根據系統的壓力設定，利用泵最佳轉速控制進行其加卸載規劃，說明其在泵輸水系統的實際應用。
本文首先比較空調系統中傳統控制系統與變頻控制系統。傳統空調系統係以泵、風機、空調箱等設備為基礎。空調系統的性能及節能可藉由加上變頻器加以改善。
接著，文中說明變頻器的種類、基本原理、配置與結構，以及其資料規劃。傳統上，在空調系統中電氣或氣動組件被用來控制閥件與擋板。傳統控制空調系統的方法存在著問題。利用變頻器改變驅動元件之速度可改善這些問題。在空調系統整合時，直接數位控制器扮演著相當重要的角色。接著本文說明直接數位控制器的結構、功能及系統規劃方法。再者，本文在靜壓控制系統及冷卻水塔風扇轉速控制系統以直接數位控制器的變頻系統作為風扇機組的控制，以說明其在空調系統中的應用。
此外，本文介紹變頻控制系統相關的組件，例如馬達、壓力感測器、流量計等驅動元件及信號擷取元件，以供節能所需之速度驅動及信號傳送，且以一直接數位控制器及一組變頻器系統為基礎，計算電量消耗。最後，文後並以直接數位控制器的變頻系統與傳統馬達系統作比較，計算在不使用變頻器的馬達固定轉速運轉與使用變頻器的可變轉速運轉狀況下，說明其能源使用效率。

關鍵字

變頻器 ； 直接數位控制器 ； 空調系統 ； 可變空氣容量系統

並列摘要

This thesis mainly discloses the applications of variable frequency drives and direct digital controllers in Heating, Ventilating and Air Conditioning (HVAC) systems. The variable frequency drives used herein are three phases 60Hz, voltage ranging from 380 - 500 VAC and the motors are based on squirrel three - phase induction motors associated with the direct digital controllers in the systems to make a multiple sets of pumps and fans to perform. This thesis focus on the pump used direct digital controllers to specify the actual applications thereof in the pump piping system depending on the pressure setting by way of optimal speed control to program the add-shedding processes.

First, this study compares the conventional control systems with the variable frequency control systems in HVAC systems. The conventional control systems are based on the sets of pumps, fans, air handling units, etc. The performances of the HVAC system and energy savings can be improved by adding the variable frequency drives.

Then the types, basic theories, arrangements and structures of the drives, and the data programming thereof are described. Conventionally, the electrical or pneumatic components are utilized to control the valves and dampers in HVAC systems. There are efficiency problems in the conventional control methods of the HVAC systems. Using the drives to vary the speeds of driving elements may improve the problems. For integrating HVAC systems, the direct digital controllers play a important role. This thesis describes the structures, functions and the system programming method of the direct digital controller. However, this work in the static pressure control system and cooling tower control system adopts DDC’s variable speed system to control the fan sets and thereby illustrating their applications in HVAC systems.

Additionally, this thesis introduces variable frequency control systems associated components such as motors, pressure sensors, flow meters, etc, for speed driving and signal transmitting with the energy savings, based on a DDC controller and/or a set of VFDs to compute the energy consumptions. Finally, this work compares the efficiency on energy consumptions within the conditions of constant speed of motors without drives and of variable speed of motors with the drives.

並列關鍵字

VFD ； DDC ； HVAC ； VAV

參考文獻

[4] B. K. Bose, Adjustable speed AC drives systems, New York: IEEE press, 1981.

[6] M. J. Coffin, Direct digital control for building HVAC systems, Norwell: Klumer Academic Publishers, 1999.

[8] Y. Zhang, C. Liu, X. Sun and F. Li , “Optimal selection and simulation software package for fan/pump and AC motor systems,” in Proc. Int. 2001 ICEMS Electrical Machines and Systems Conf., Shenyang, China, vol. 1, Aug. 18-20, 2001, pp. 432 – 435.

[9] D. Stephenson, “Simple Guide for Design of Air Vessels for Water Hammer Protection of Pumping Lines,” Journal of Hydraulic Engineering, vol. 128, no. 8, Aug. 2002, pp. 792–797.

[11] G. Irvine and I. H. Gibson, “The use of variable frequency drives as a final control element in the petroleum industry,” in Conf. Record of the 2000 IEEE Industry Applications Conf., Rome, Italy, vol. 4, Oct. 8-12, 2000, pp. 2749 - 2758.