螺旋滿液式冰水主機之開發與性能評估

Development and Performance Evaluation of Screw Flooded Chillers

賴進昌(Chin-Chang Lai)

指導教授 ： 柯明村

國立臺北科技大學/機電學院/冷凍空調工程系所/碩士(2005年)

摘要

空調系統之用電量為國內夏季尖峰負載之主要因素，其中冰水主機更佔整體空調用電的60%，因此在節約能源、降低尖峰負載的目標之下，使用較高效率之冰水機是必然的趨勢。本文以R-134a為冰水機系統的冷媒，採用兩級壓縮來取代傳統之單級壓縮，期望以節省壓縮功來達到性能的改善，實際開發了以R-134a為冷媒的兩段壓縮螺旋主機之系統，並發展一套系統性能分析的程式，進行系統模擬來輔助實際系統之分析與設計。本研究在模擬之前預先建立流體流經各元件的數學模式，利用模組化的概念組合成系統模型，應用區域分析架構，以ε-NTU法來分析熱交換器各區段之熱傳；使用Microsoft Excel工作表(Worksheet)作為各種設計條件的輸入與設計輸出的介面，冷媒性質隨實際分析狀態而改變來求得冷媒熱物性，以質量與能量守恆定律為理論基礎，模擬輸出冷卻能力、冷凝能力、耗電量、能源效率比等參數，作為能耗及節能的分析依據。
過去由於滿液式冰水機在技術層面的問題以及製造成本偏高等因素，直膨式機組的選擇在國內仍有其不可撼動的地位，但滿液式系統的效率遠勝於直膨式系統，這是無庸置疑的。本論文亦介紹了滿液式冰水機的開發，克服了技術層面的問題，以及製造成本的合理化，滿液式冰水機將為本國的節能策略開啟嶄新的一頁。

關鍵字

高效率冰水機 ； 滿液式系統 ； 螺旋機

並列摘要

The electricity consumption of air conditioning systems is the main factor of domestic peak load in summer, among which chillers occupy 60% of electricity consumption of the whole system. Therefore, under the goals of saving energy and reducing peak load, using the chillers with higher efficiency is an inevitable trend. This study adopts two-stage compression to replace the traditional single-stage compression to improve the coefficiency of performance by saving the compression work, actually developed the system of two-stage compression screw chillers using R-134a as the refrigerant and established a program for system performance analysis to conduct system simulation for assisting the design and evaluation of real chillers. This research simulated the flow through each component by the previously established mathematical mode and used modularized concept to establish the analysis models, to study the heat transfer of each section of heat exchangers by ε-NTU method. This research also utilized the Microsoft Excel as the interface of input and output of various design parameters, and the refrigerant quality can be changed with actual analysis condition to meet the actual running situations; By solving conservation laws of mass and energy as the theory foundation to simulate various parameters, the cooling capacity, condensation capacity, electricity consumption, and energy efficiency ratios as the analysis basis of energy consumption and energy conservation, where obtained and discussed.
In the past, because technical problems and high manufacturing cost of flooded type chillers, the domestic status of direct expansion machine groups is still unchangeable; however, it’s undoubted that the efficiency of flooded type is much better than that of direct expansion system. This thesis also introduces the development of related technical problems of flooded type chillers and the rationalization of manufacturing cost.

並列關鍵字

High Efficiency Chiller ； Flooded Type Evaporator ； Semi-hermetic Rotary Screw Compressor.

參考文獻

[1] McMullan J.T.,”Refrigeration and the environment – issues and strategies for the future”, International Journal of Refrigeration, Vol. 25, PP.89-99, 2002.

[6] Chen Z.J. and Lin W.H., “Dynamic simulation andoptimal matching of a small-scale refrigeration system”, Int. J Refrig., Vol. 14, PP.329-335 , 1991.

[7] Farzad M. and O’Neal , D.L., ”System performance characteristics of an air conditioner over a range of charging conditions”, Int. J Refrig., Vol.14, PP.321-328, 1991.

[8] Slaim, M. A., Sadasivam, M. and Balakrishnan, A. R., “Transient analysis of heat pump assisted distillation systems-1 The heat pump.”, Int. J. Energy Research, Vol. 15, PP.123-135, 1991.

[9] Ng KC, Bong TY, Chua HT. “Performance evaluation of centrifugal chillers in an air-conditioning plant with the building automation system (BAS).” Proc Inst Mech Engrs, Vol.209, PP.249-55, 1994.